[ttml2] move snapshots up one to preserve image references
authorGlenn Adams <glenn@skynav.com>
Wed, 14 Jan 2015 09:53:09 -0700
changeset 833 cfdbb163c700
parent 832 2460a4dbe6f9
child 834 848606260c44
[ttml2] move snapshots up one to preserve image references
ttml2/spec/snapshots/ttml2-20150114-pre-fpwd-review-1.html
ttml2/spec/ttml2-20150114-pre-fpwd-review-1.html
--- a/ttml2/spec/snapshots/ttml2-20150114-pre-fpwd-review-1.html	Wed Jan 14 09:49:06 2015 -0700
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,10430 +0,0 @@
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-  PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
-<html lang="en-us"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>Timed Text Markup Language 2 (TTML2) -- (Editor's copy)</title><style type="text/css">
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-</style><link rel="stylesheet" type="text/css" href="https://www.w3.org/StyleSheets/TR/W3C-ED.css"></head><body>Last Modified: $Date: 2015/01/14 16:45:15 $<div id="revisions"></div><div class="head">
-<h1><a id="title"></a>Timed Text Markup Language 2 (TTML2)</h1>
-<h2><a id="w3c-doctype"></a>Editors' copy $Date: 2015/01/14 16:45:15 $ @@ @@@@ @@@@</h2><dl><dt>This version:</dt><dd>
-<a href="ttml2.html">ttml2.html</a>
-</dd><dt>Latest version:</dt><dd><a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml2/spec/ttml2.html?content-type=text/html;charset=utf-8">https://dvcs.w3.org/hg/ttml/raw-file/default/ttml2/spec/ttml2.html?content-type=text/html;charset=utf-8</a></dd><dt>Previous version:</dt><dd>
-<a href="http://www.w3.org/TR/2013/REC-ttml1-20130924/">http://www.w3.org/TR/2013/REC-ttml1-20130924/</a>
-</dd><dt>Editor:</dt><dd>Glenn Adams, Skynav, Inc.</dd><dt>Contributing Authors:</dt><dd>Mike Dolan, Invited Expert</dd><dd>Sean Hayes, Microsoft</dd><dd>Frans de Jong, European Broadcasting Union</dd><dd>Pierre-Anthony Lemieux, MovieLabs</dd><dd>Nigel Megitt, British Broadcasting Corporation</dd><dd>Dave Singer, Apple Computer</dd><dd>Jerry Smith, Microsoft</dd><dd>Andreas Tai, Invited Expert</dd></dl><p>Please refer to the <a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml10/spec/ttml-issues.html">errata</a> for this document, which may
-      include normative corrections.</p><p>See also <a href="http://www.w3.org/2003/03/Translations/byTechnology?technology=ttml2"><strong>translations</strong></a>.</p><p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>&nbsp;©&nbsp;@@@@&nbsp;<a href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>, <a href="http://ev.buaa.edu.cn/">Beihang</a>), All Rights Reserved. W3C <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p></div><hr><div>
-<h2><a id="abstract"></a>Abstract</h2><p>This document specifies the Timed Text Markup Language (TTML), Version 2, also known as TTML2,
-in terms of a vocabulary and semantics thereof.</p><p>The Timed Text Markup Language is a content type that represents
-timed text media for the purpose of interchange among authoring
-systems. Timed text is textual information that is intrinsically or
-extrinsically associated with timing information.</p><p>It is intended to be used
-for the purpose of transcoding or exchanging timed text information
-among legacy distribution content formats presently in use for
-subtitling and captioning functions.</p><p>In addition to being used for interchange among legacy distribution content
-formats, TTML Content may be used directly as a distribution format,
-for example, providing a standard content format to reference from a <code>&lt;track&gt;</code>
-element in an HTML5 document, or a <code>&lt;text&gt;</code> or 
-<code>&lt;textstream&gt;</code> media element in a <a href="#smil3">[SMIL 3.0]</a> document.</p></div><div>
-<h2><a id="status"></a>Status of this Document</h2><p><strong>This document is an editor's copy that has
-        no official standing.</strong></p><p></p></div><div class="toc">
-<h2><a id="contents"></a>Table of Contents</h2><p class="toc">1 <a href="#intro">Introduction</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;1.1 <a href="#model">System Model</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;1.2 <a href="#example">Document Example</a><br>
-2 <a href="#definitions">Definitions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;2.1 <a href="#acronyms">Acronyms</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;2.2 <a href="#terms">Terminology</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;2.3 <a href="#conventions">Documentation Conventions</a><br>
-3 <a href="#conformance">Conformance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;3.1 <a href="#conformance-content">Document Conformance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;3.2 <a href="#conformance-processor">Processor Conformance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.2.1 <a href="#conformance-generic-processor">Generic Processor Conformance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.2.2 <a href="#conformance-transformation-processor">Transformation Processor Conformance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.2.3 <a href="#conformance-presentation-processor">Presentation Processor Conformance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;3.3 <a href="#claims">Claims</a><br>
-4 <a href="#doctypes">Document Types</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;4.1 <a href="#ttml-content-doctype">TTML Content Document Type</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;4.2 <a href="#ttml-intermediate-doctype">TTML Intermediate Document Type</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;4.3 <a href="#ttml-profile-doctype">TTML Profile Document Type</a><br>
-5 <a href="#vocabulary">Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;5.1 <a href="#vocabulary-namespaces">Namespaces</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;5.2 <a href="#vocabulary-profiling">Profiling</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.1 <a href="#vocabulary-profile-introduction">Introduction</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.2 <a href="#semantics-profile-examples">Profile Examples</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.3 <a href="#vocabulary-profile-designators">Profile Designators</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.3.1 <a href="#vocabulary-profile-standard-designators">Standard Designators</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.4 <a href="#semantics-profile-semantics">Profile Semantics</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.4.1 <a href="#semantics-profile-state">Profile State Object Concepts</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.4.2 <a href="#semantics-content-profile-processing">Content Profile Semantics</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.4.3 <a href="#semantics-processor-profile-processing">Processor Profile Semantics</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;5.3 <a href="#vocabulary-overview">Catalog</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.3.1 <a href="#core-vocabulary-overview">Core Catalog</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.3.2 <a href="#extension-vocabulary-overview">Extension Catalog</a><br>
-6 <a href="#profile">Profile</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;6.1 <a href="#profile-element-vocabulary">Profile Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.1 <a href="#profile-vocabulary-profile">ttp:profile</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.2 <a href="#profile-vocabulary-features">ttp:features</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.3 <a href="#profile-vocabulary-feature">ttp:feature</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.4 <a href="#profile-vocabulary-extensions">ttp:extensions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.5 <a href="#profile-vocabulary-extension">ttp:extension</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;6.2 <a href="#profile-attribute-vocabulary">Profile Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.1 <a href="#profile-attribute-contentProfiles">ttp:contentProfiles</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.2 <a href="#profile-attribute-contentProfileCombination">ttp:contentProfileCombination</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.3 <a href="#profile-attribute-inferProcessorProfileMethod">ttp:inferProcessorProfileMethod</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.4 <a href="#profile-attribute-inferProcessorProfileSource">ttp:inferProcessorProfileSource</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.5 <a href="#profile-attribute-permitFeatureNarrowing">ttp:permitFeatureNarrowing</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.6 <a href="#profile-attribute-permitFeatureWidening">ttp:permitFeatureWidening</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.7 <a href="#profile-attribute-profile">ttp:profile</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.8 <a href="#profile-attribute-processorProfiles">ttp:processorProfiles</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.9 <a href="#profile-attribute-processorProfileCombination">ttp:processorProfileCombination</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.10 <a href="#profile-attribute-validation">ttp:validation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.11 <a href="#profile-attribute-validationAction">ttp:validationAction</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.12 <a href="#profile-attribute-version">ttp:version</a><br>
-7 <a href="#parameter">Parameter</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;7.1 <a href="#parameter-element-vocabulary">Parameter Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;7.2 <a href="#parameter-attribute-vocabulary">Parameter Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.1 <a href="#parameter-attribute-cellResolution">ttp:cellResolution</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.2 <a href="#parameter-attribute-clockMode">ttp:clockMode</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.3 <a href="#parameter-attribute-dropMode">ttp:dropMode</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.4 <a href="#parameter-attribute-frameRate">ttp:frameRate</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.5 <a href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultiplier</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.6 <a href="#parameter-attribute-markerMode">ttp:markerMode</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.7 <a href="#parameter-attribute-mediaDuration">ttp:mediaDuration</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.8 <a href="#parameter-attribute-mediaOffset">ttp:mediaOffset</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.9 <a href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.10 <a href="#parameter-attribute-storageAspectRatio">ttp:storageAspectRatio</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.11 <a href="#parameter-attribute-subFrameRate">ttp:subFrameRate</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.12 <a href="#parameter-attribute-tickRate">ttp:tickRate</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.13 <a href="#parameter-attribute-timeBase">ttp:timeBase</a><br>
-8 <a href="#content">Content</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;8.1 <a href="#content-element-vocabulary">Content Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.1 <a href="#document-structure-vocabulary-tt">tt</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.2 <a href="#document-structure-vocabulary-head">head</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.3 <a href="#document-structure-vocabulary-body">body</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.4 <a href="#content-vocabulary-div">div</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.5 <a href="#content-vocabulary-p">p</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.6 <a href="#content-vocabulary-span">span</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.7 <a href="#content-vocabulary-br">br</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;8.2 <a href="#content-attribute-vocabulary">Content Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.1 <a href="#content-attribute-condition">condition</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.2 <a href="#content-attribute-xlink-arcrole">xlink:arcrole</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.3 <a href="#content-attribute-xlink-href">xlink:href</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.4 <a href="#content-attribute-xlink-role">xlink:role</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.5 <a href="#content-attribute-xlink-show">xlink:show</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.6 <a href="#content-attribute-xlink-title">xlink:title</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.7 <a href="#content-attribute-xml-id">xml:id</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.8 <a href="#content-attribute-xml-lang">xml:lang</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.9 <a href="#content-attribute-xml-space">xml:space</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;8.3 <a href="#content-value-expressions">Content Value Expressions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.1 <a href="#content-value-arguments">&lt;arguments&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.2 <a href="#content-value-bound-parameter">&lt;bound-parameter&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.3 <a href="#content-value-condition">&lt;condition&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.4 <a href="#content-value-condition-function">&lt;condition-function&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.5 <a href="#content-value-expression">&lt;expression&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.6 <a href="#content-value-media-function">&lt;media-function&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.7 <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.8 <a href="#content-value-parameter-function">&lt;parameter-function&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.9 <a href="#content-value-supports-function">&lt;supports-function&gt;</a><br>
-9 <a href="#embedded-content">Embedded Content</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;9.1 <a href="#embedded-content-element-vocabulary">Embedded Content Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.1 <a href="#embedded-content-vocabulary-audio">audio</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.2 <a href="#embedded-content-vocabulary-chunk">chunk</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.3 <a href="#embedded-content-vocabulary-data">data</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.4 <a href="#embedded-content-vocabulary-font">font</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.5 <a href="#embedded-content-vocabulary-image">image</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.6 <a href="#embedded-content-vocabulary-resources">resources</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.7 <a href="#embedded-content-vocabulary-source">source</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;9.2 <a href="#embedded-content-attribute-vocabulary">Embedded Content Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.1 <a href="#embedded-content-attribute-encoding">encoding</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.2 <a href="#embedded-content-attribute-format">format</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.3 <a href="#embedded-content-attribute-src">src</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.4 <a href="#embedded-content-attribute-type">type</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;9.3 <a href="#embedded-content-value-expressions">Embedded Content Value Expressions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.1 <a href="#embedded-content-value-audio">&lt;audio&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.2 <a href="#embedded-content-value-audio-format">&lt;audio-format&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.3 <a href="#embedded-content-value-data">&lt;data&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.4 <a href="#embedded-content-value-data-format">&lt;data-format&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.5 <a href="#embedded-content-value-font">&lt;font&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.6 <a href="#embedded-content-value-font-format">&lt;font-format&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.7 <a href="#embedded-content-value-image">&lt;image&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.8 <a href="#embedded-content-value-image-format">&lt;image-format&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.9 <a href="#embedded-content-value-unicode-range">&lt;unicode-range&gt;</a><br>
-10 <a href="#styling">Styling</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;10.1 <a href="#styling-element-vocabulary">Styling Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.1.1 <a href="#styling-vocabulary-initial">initial</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.1.2 <a href="#styling-vocabulary-style">style</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.1.3 <a href="#styling-vocabulary-styling">styling</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;10.2 <a href="#styling-attribute-vocabulary">Styling Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.1 <a href="#style-attribute-style">style</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.2 <a href="#style-attribute-backgroundColor">tts:backgroundColor</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.3 <a href="#style-attribute-backgroundImage">tts:backgroundImage</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.4 <a href="#style-attribute-backgroundPosition">tts:backgroundPosition</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.5 <a href="#style-attribute-backgroundRepeat">tts:backgroundRepeat</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.6 <a href="#style-attribute-border">tts:border</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.7 <a href="#style-attribute-color">tts:color</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.8 <a href="#style-attribute-direction">tts:direction</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.9 <a href="#style-attribute-display">tts:display</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.10 <a href="#style-attribute-displayAlign">tts:displayAlign</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.11 <a href="#style-attribute-extent">tts:extent</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.12 <a href="#style-attribute-fontFamily">tts:fontFamily</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.13 <a href="#style-attribute-fontKerning">tts:fontKerning</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.14 <a href="#style-attribute-fontSelectionStrategy">tts:fontSelectionStrategy</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.15 <a href="#style-attribute-fontShear">tts:fontShear</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.16 <a href="#style-attribute-fontSize">tts:fontSize</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.17 <a href="#style-attribute-fontStyle">tts:fontStyle</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.18 <a href="#style-attribute-fontVariantPosition">tts:fontVariantPosition</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.19 <a href="#style-attribute-fontWeight">tts:fontWeight</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.20 <a href="#style-attribute-height">tts:height</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.21 <a href="#style-attribute-letterSpacing">tts:letterSpacing</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.22 <a href="#style-attribute-lineHeight">tts:lineHeight</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.23 <a href="#style-attribute-opacity">tts:opacity</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.24 <a href="#style-attribute-origin">tts:origin</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.25 <a href="#style-attribute-overflow">tts:overflow</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.26 <a href="#style-attribute-padding">tts:padding</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.27 <a href="#style-attribute-position">tts:position</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.28 <a href="#style-attribute-ruby">tts:ruby</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.29 <a href="#style-attribute-rubyAlign">tts:rubyAlign</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.30 <a href="#style-attribute-rubyOffset">tts:rubyOffset</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.31 <a href="#style-attribute-rubyPosition">tts:rubyPosition</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.32 <a href="#style-attribute-showBackground">tts:showBackground</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.33 <a href="#style-attribute-textAlign">tts:textAlign</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.34 <a href="#style-attribute-textCombine">tts:textCombine</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.35 <a href="#style-attribute-textDecoration">tts:textDecoration</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.36 <a href="#style-attribute-textEmphasis">tts:textEmphasis</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.37 <a href="#style-attribute-textOrientation">tts:textOrientation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.38 <a href="#style-attribute-textOutline">tts:textOutline</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.39 <a href="#style-attribute-textShadow">tts:textShadow</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.40 <a href="#style-attribute-unicodeBidi">tts:unicodeBidi</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.41 <a href="#style-attribute-visibility">tts:visibility</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.42 <a href="#style-attribute-width">tts:width</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.43 <a href="#style-attribute-wrapOption">tts:wrapOption</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.44 <a href="#style-attribute-writingMode">tts:writingMode</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.45 <a href="#style-attribute-zIndex">tts:zIndex</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;10.3 <a href="#styling-style-value-expressions">Styling Value Expressions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.1 <a href="#style-value-alpha">&lt;alpha&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.2 <a href="#style-value-borderColor">&lt;borderColor&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.3 <a href="#style-value-borderStyle">&lt;borderStyle&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.4 <a href="#style-value-borderWidth">&lt;borderWidth&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.5 <a href="#style-value-color">&lt;color&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.6 <a href="#style-value-digit">&lt;digit&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.7 <a href="#style-value-emphasisColor">&lt;emphasisColor&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.8 <a href="#style-value-emphasisStyle">&lt;emphasisStyle&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.9 <a href="#style-value-emphasisPosition">&lt;emphasisPosition&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.10 <a href="#style-value-familyName">&lt;familyName&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.11 <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.12 <a href="#style-value-hexDigit">&lt;hexDigit&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.13 <a href="#style-value-integer">&lt;integer&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.14 <a href="#style-value-length">&lt;length&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.15 <a href="#style-value-measure">&lt;measure&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.16 <a href="#style-value-namedColor">&lt;namedColor&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.17 <a href="#style-value-non-negative-integer">&lt;non-negative-integer&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.18 <a href="#style-value-number">&lt;number&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.19 <a href="#style-value-percentage">&lt;percentage&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.20 <a href="#style-value-position">&lt;position&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.21 <a href="#style-value-shadow">&lt;shadow&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;10.4 <a href="#semantics-styling">Styling Semantics</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1 <a href="#semantics-style-association">Style Association</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1.1 <a href="#semantics-style-association-inline">Inline Styling</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1.2 <a href="#semantics-style-association-referential">Referential Styling</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1.3 <a href="#semantics-style-association-chained-referential">Chained Referential Styling</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1.4 <a href="#semantics-style-association-nested">Nested Styling</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.2 <a href="#semantics-style-inheritance">Style Inheritance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.2.1 <a href="#semantics-style-inheritance-content">Content Style Inheritance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.2.2 <a href="#semantics-style-inheritance-region">Region Style Inheritance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.2.3 <a href="#semantics-style-inheritance-root">Root Style Inheritance</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.3 <a href="#semantics-style-resolution-value-categories">Style Resolution Value Categories</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.3.1 <a href="#semantics-style-resolved-value-category-specified">Specified Values</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.3.2 <a href="#semantics-style-resolved-value-category-computed">Computed Values</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.3.3 <a href="#semantics-style-resolved-value-category-actual">Actual Values</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4 <a href="#semantics-style-resolution-processing">Style Resolution Processing</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4.1 <a href="#semantics-style-resolution-processing-definitions">Conceptual Definitions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4.2 <a href="#semantics-style-resolution-processing-sss">Specified Style Set Processing</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4.3 <a href="#semantics-style-resolution-processing-css">Computed Style Set Processing</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4.4 <a href="#semantics-style-resolution-process-overall">Style Resolution Process</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.5 <a href="#semantics-style-automatic-measure-calculation">Automatic Measure Calculation</a><br>
-11 <a href="#layout">Layout</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;11.1 <a href="#layout-element-vocabulary">Layout Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.1.1 <a href="#layout-vocabulary-layout">layout</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.1.2 <a href="#layout-vocabulary-region">region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;11.2 <a href="#layout-attribute-vocabulary">Layout Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.2.1 <a href="#layout-attribute-region">region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;11.3 <a href="#semantics-layout">Layout Semantics</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1 <a href="#semantics-region-layout">Region Layout and Presentation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.1 <a href="#semantics-default-region">Default Region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.2 <a href="#semantics-inline-regions">Inline Regions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.3 <a href="#semantics-region-layout-step-1">Intermediate Synchronic Document Construction</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.4 <a href="#semantics-region-layout-step-2">Synchronic Flow Processing</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.5 <a href="#semantics-region-layout-example">Elaborated Example (Non-Normative)</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.2 <a href="#semantics-line-layout">Line Layout</a><br>
-12 <a href="#timing">Timing</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;12.1 <a href="#timing-element-vocabulary">Timing Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;12.2 <a href="#timing-attribute-vocabulary">Timing Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.1 <a href="#timing-attribute-begin">begin</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.2 <a href="#timing-attribute-dur">dur</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.3 <a href="#timing-attribute-end">end</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.4 <a href="#timing-attribute-timeContainer">timeContainer</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;12.3 <a href="#timing-time-value-expressions">Time Value Expressions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.3.1 <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;12.4 <a href="#semantics-timing">Timing Semantics</a><br>
-13 <a href="#animation">Animation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;13.1 <a href="#animation-element-vocabulary">Animation Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.1.1 <a href="#animation-vocabulary-animate">animate</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.1.2 <a href="#animation-vocabulary-animation">animation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.1.3 <a href="#animation-vocabulary-set">set</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;13.2 <a href="#animation-attribute-vocabulary">Animation Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.2.1 <a href="#animation-attribute-animate">animate</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;13.3 <a href="#animation-value-expressions">Animation Value Expressions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.1 <a href="#animation-value-animationValue">&lt;animationValue&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.2 <a href="#animation-value-animationValueList">&lt;animationValueList&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.3 <a href="#animation-value-calcMode">&lt;calcMode&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.4 <a href="#animation-value-fill">&lt;fill&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.5 <a href="#animation-value-keySplines">&lt;keySplines&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.6 <a href="#animation-value-keyTimes">&lt;keyTimes&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.7 <a href="#animation-value-repeatCount">&lt;repeatCount&gt;</a><br>
-14 <a href="#metadata">Metadata</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;14.1 <a href="#metadata-element-vocabulary">Metadata Element Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.1 <a href="#metadata-vocabulary-metadata">metadata</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.2 <a href="#metadata-vocabulary-actor">ttm:actor</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.3 <a href="#metadata-vocabulary-agent">ttm:agent</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.4 <a href="#metadata-vocabulary-copyright">ttm:copyright</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.5 <a href="#metadata-vocabulary-desc">ttm:desc</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.6 <a href="#metadata-vocabulary-item">ttm:item</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.7 <a href="#metadata-vocabulary-name">ttm:name</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.8 <a href="#metadata-vocabulary-title">ttm:title</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;14.2 <a href="#metadata-attribute-vocabulary">Metadata Attribute Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.2.1 <a href="#metadata-attribute-agent">ttm:agent</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.2.2 <a href="#metadata-attribute-role">ttm:role</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;14.3 <a href="#metadata-value-expressions">Metadata Value Expressions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.3.1 <a href="#metadata-value-item-name">&lt;item-name&gt;</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.3.2 <a href="#metadata-value-named-item">&lt;named-item&gt;</a><br>
-</p>
-<h3><a id="appendices"></a>Appendices</h3><p class="toc">A <a href="#concrete-encoding">Concrete Encoding</a><br>
-B <a href="#reduced-infoset">Reduced XML Infoset</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;B.1 <a href="#reduced-infoset-document">Document Information Item</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;B.2 <a href="#reduced-infoset-element">Element Information Item</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;B.3 <a href="#reduced-infoset-attribute">Attribute Information Item</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;B.4 <a href="#reduced-infoset-character">Character Information Item</a><br>
-C <a href="#schemas">Schemas</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;C.1 <a href="#ttml-schema-rnc">Relax NG Compact (RNC) Schema</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;C.2 <a href="#ttml-schema-xsd">XML Schema Definition (XSD) Schema</a><br>
-D <a href="#media-types-registration">Media Type Registration</a><br>
-E <a href="#features">Features</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;E.1 <a href="#feature-designations">Feature Designations</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.1 <a href="#feature-animation">#animation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.2 <a href="#feature-backgroundColor">#backgroundColor</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.3 <a href="#feature-backgroundColor-block">#backgroundColor-block</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.4 <a href="#feature-backgroundColor-inline">#backgroundColor-inline</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.5 <a href="#feature-backgroundColor-region">#backgroundColor-region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.6 <a href="#feature-bidi">#bidi</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.7 <a href="#feature-border">#border</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.8 <a href="#feature-cellResolution">#cellResolution</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.9 <a href="#feature-clockMode">#clockMode</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.10 <a href="#feature-clockMode-gps">#clockMode-gps</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.11 <a href="#feature-clockMode-local">#clockMode-local</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.12 <a href="#feature-clockMode-utc">#clockMode-utc</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.13 <a href="#feature-color">#color</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.14 <a href="#feature-content">#content</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.15 <a href="#feature-core">#core</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.16 <a href="#feature-direction">#direction</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.17 <a href="#feature-display">#display</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.18 <a href="#feature-display-block">#display-block</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.19 <a href="#feature-display-inline">#display-inline</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.20 <a href="#feature-display-region">#display-region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.21 <a href="#feature-displayAlign">#displayAlign</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.22 <a href="#feature-dropMode">#dropMode</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.23 <a href="#feature-dropMode-dropNTSC">#dropMode-dropNTSC</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.24 <a href="#feature-dropMode-dropPAL">#dropMode-dropPAL</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.25 <a href="#feature-dropMode-nonDrop">#dropMode-nonDrop</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.26 <a href="#feature-extent">#extent</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.27 <a href="#feature-extent-region">#extent-region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.28 <a href="#feature-extent-root">#extent-root</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.29 <a href="#feature-fontFamily">#fontFamily</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.30 <a href="#feature-fontFamily-generic">#fontFamily-generic</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.31 <a href="#feature-fontFamily-non-generic">#fontFamily-non-generic</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.32 <a href="#feature-fontSize">#fontSize</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.33 <a href="#feature-fontSize-anamorphic">#fontSize-anamorphic</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.34 <a href="#feature-fontSize-isomorphic">#fontSize-isomorphic</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.35 <a href="#feature-fontStyle">#fontStyle</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.36 <a href="#feature-fontStyle-italic">#fontStyle-italic</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.37 <a href="#feature-fontStyle-oblique">#fontStyle-oblique</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.38 <a href="#feature-fontWeight">#fontWeight</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.39 <a href="#feature-fontWeight-bold">#fontWeight-bold</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.40 <a href="#feature-frameRate">#frameRate</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.41 <a href="#feature-frameRateMultiplier">#frameRateMultiplier</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.42 <a href="#feature-layout">#layout</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.43 <a href="#feature-length">#length</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.44 <a href="#feature-length-cell">#length-cell</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.45 <a href="#feature-length-em">#length-em</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.46 <a href="#feature-length-integer">#length-integer</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.47 <a href="#feature-length-negative">#length-negative</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.48 <a href="#feature-length-percentage">#length-percentage</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.49 <a href="#feature-length-pixel">#length-pixel</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.50 <a href="#feature-length-positive">#length-positive</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.51 <a href="#feature-length-real">#length-real</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.52 <a href="#feature-lineBreak-uax14">#lineBreak-uax14</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.53 <a href="#feature-lineHeight">#lineHeight</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.54 <a href="#feature-markerMode">#markerMode</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.55 <a href="#feature-markerMode-continuous">#markerMode-continuous</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.56 <a href="#feature-markerMode-discontinuous">#markerMode-discontinuous</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.57 <a href="#feature-metadata">#metadata</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.58 <a href="#feature-nested-div">#nested-div</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.59 <a href="#feature-nested-span">#nested-span</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.60 <a href="#feature-opacity">#opacity</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.61 <a href="#feature-origin">#origin</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.62 <a href="#feature-overflow">#overflow</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.63 <a href="#feature-overflow-visible">#overflow-visible</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.64 <a href="#feature-padding">#padding</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.65 <a href="#feature-padding-1">#padding-1</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.66 <a href="#feature-padding-2">#padding-2</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.67 <a href="#feature-padding-3">#padding-3</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.68 <a href="#feature-padding-4">#padding-4</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.69 <a href="#feature-pixelAspectRatio">#pixelAspectRatio</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.70 <a href="#feature-presentation">#presentation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.71 <a href="#feature-profile">#profile</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.72 <a href="#feature-showBackground">#showBackground</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.73 <a href="#feature-structure">#structure</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.74 <a href="#feature-styling">#styling</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.75 <a href="#feature-styling-chained">#styling-chained</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.76 <a href="#feature-styling-inheritance-content">#styling-inheritance-content</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.77 <a href="#feature-styling-inheritance-region">#styling-inheritance-region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.78 <a href="#feature-styling-inline">#styling-inline</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.79 <a href="#feature-styling-nested">#styling-nested</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.80 <a href="#feature-styling-referential">#styling-referential</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.81 <a href="#feature-subFrameRate">#subFrameRate</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.82 <a href="#feature-textAlign">#textAlign</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.83 <a href="#feature-textAlign-absolute">#textAlign-absolute</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.84 <a href="#feature-textAlign-relative">#textAlign-relative</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.85 <a href="#feature-textDecoration">#textDecoration</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.86 <a href="#feature-textDecoration-over">#textDecoration-over</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.87 <a href="#feature-textDecoration-through">#textDecoration-through</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.88 <a href="#feature-textDecoration-under">#textDecoration-under</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.89 <a href="#feature-textOrientation">#textOrientation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.90 <a href="#feature-textOutline">#textOutline</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.91 <a href="#feature-textOutline-blurred">#textOutline-blurred</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.92 <a href="#feature-textOutline-unblurred">#textOutline-unblurred</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.93 <a href="#feature-tickRate">#tickRate</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.94 <a href="#feature-timeBase-clock">#timeBase-clock</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.95 <a href="#feature-timeBase-media">#timeBase-media</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.96 <a href="#feature-timeBase-smpte">#timeBase-smpte</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.97 <a href="#feature-timeContainer">#timeContainer</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.98 <a href="#feature-time-clock">#time-clock</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.99 <a href="#feature-time-clock-with-frames">#time-clock-with-frames</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.100 <a href="#feature-time-offset">#time-offset</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.101 <a href="#feature-time-offset-with-frames">#time-offset-with-frames</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.102 <a href="#feature-time-offset-with-ticks">#time-offset-with-ticks</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.103 <a href="#feature-timing">#timing</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.104 <a href="#feature-transformation">#transformation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.105 <a href="#feature-unicodeBidi">#unicodeBidi</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.106 <a href="#feature-version">#version</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.107 <a href="#feature-visibility">#visibility</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.108 <a href="#feature-visibility-block">#visibility-block</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.109 <a href="#feature-visibility-inline">#visibility-inline</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.110 <a href="#feature-visibility-region">#visibility-region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.111 <a href="#feature-wrapOption">#wrapOption</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.112 <a href="#feature-writingMode">#writingMode</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.113 <a href="#feature-writingMode-vertical">#writingMode-vertical</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.114 <a href="#feature-writingMode-horizontal">#writingMode-horizontal</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.115 <a href="#feature-writingMode-horizontal-lr">#writingMode-horizontal-lr</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.116 <a href="#feature-writingMode-horizontal-rl">#writingMode-horizontal-rl</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.117 <a href="#feature-zIndex">#zIndex</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;E.2 <a href="#feature-support">Feature Support</a><br>
-F <a href="#extensions">Extensions</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;F.1 <a href="#extension-designations">Extension Designations</a><br>
-G <a href="#standard-profiles">Standard Profiles</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;G.1 <a href="#profile-ttml2-full">TTML2 Full Profile</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;G.2 <a href="#profile-ttml2-presentation">TTML2 Presentation Profile</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;G.3 <a href="#profile-ttml2-transformation">TTML2 Transformation Profile</a><br>
-H <a href="#time-expression-semantics">Time Expression Semantics</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;H.1 <a href="#time-expression-semantics-clock">Clock Time Base</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;H.2 <a href="#time-expression-semantics-media">Media Time Base</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;H.3 <a href="#time-expression-semantics-smpte">SMPTE Time Base</a><br>
-I <a href="#isd">Intermediate Document Syntax</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;I.1 <a href="#isd-vocabulary">ISD Vocabulary</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I.1.1 <a href="#isd-vocabulary-sequence">isd:sequence</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I.1.2 <a href="#isd-vocabulary-isd">isd:isd</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I.1.3 <a href="#isd-vocabulary-css">isd:css</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I.1.4 <a href="#isd-vocabulary-region">isd:region</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;I.2 <a href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;I.3 <a href="#isd-interchange">ISD Interchange</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;I.4 <a href="#isd-examples">ISD Examples</a><br>
-J <a href="#references">References</a><br>
-K <a href="#other-references">Other References</a> (Non-Normative)<br>
-L <a href="#requirements">Requirements</a> (Non-Normative)<br>
-M <a href="#derivation">Vocabulary Derivation</a> (Non-Normative)<br>
-&nbsp;&nbsp;&nbsp;&nbsp;M.1 <a href="#d3e37582">Element Derivation</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;M.2 <a href="#d3e38099">Attribute Derivation</a><br>
-N <a href="#qa">QA Framework Compliance</a> (Non-Normative)<br>
-&nbsp;&nbsp;&nbsp;&nbsp;N.1 <a href="#d3e39092">Requirements</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;N.2 <a href="#d3e39256">Guidelines</a><br>
-O <a href="#streaming">Streaming TTML Content</a> (Non-Normative)<br>
-P <a href="#common-styling">Common Caption Style Examples</a> (Non-Normative)<br>
-&nbsp;&nbsp;&nbsp;&nbsp;P.1 <a href="#pop-on-example">Pop-On Caption Example</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;P.2 <a href="#roll-up-example">Roll-Up Caption Example</a><br>
-&nbsp;&nbsp;&nbsp;&nbsp;P.3 <a href="#paint-on-example">Paint-On Caption Example</a><br>
-Q <a href="#cea708-mapping">CEA708 Mapping Considerations</a> (Non-Normative)<br>
-R <a href="#acknowledgments">Acknowledgments</a> (Non-Normative)<br>
-</p></div><hr><div class="body"><div class="div1">
-<h2><a id="intro"></a>1 Introduction</h2><p><em>Unless specified otherwise, this section and its sub-sections are non-normative.</em></p><p>The Timed Text Markup Language (TTML), Version 2, also referred to as TTML2,
-provides a standardized representation of a particular subset of
-textual information with which stylistic, layout, and timing semantics are associated by
-an author or an authoring system for the purpose of interchange and processing.</p><p>TTML is expressly designed to meet only a limited set of requirements
-established by <a href="#ttaf1-req">[TTAF1-REQ]</a>, and summarized in <a href="#requirements"><b>L Requirements</b></a>. In particular, only those requirements which service the
-need of performing interchange with existing, legacy distribution systems are
-satisfied.</p><p>In addition to being used for interchange among legacy distribution content
-formats, TTML Content may be used directly as a distribution format, providing, for
-example, a standard content format to reference from a <code>&lt;track&gt;</code>
-element in an HTML5 document, or a <code>&lt;text&gt;</code> or 
-<code>&lt;textstream&gt;</code> media element in a <a href="#smil3">[SMIL 3.0]</a> document. Certain properties of TTML support
-streamability of content, as described in <a href="#streaming"><b>O Streaming TTML Content</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>While TTML is not expressly designed for direct (embedded) integration into an
-HTML or a SMIL document instance, such integration is not precluded.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>In some contexts of use, it may be appropriate to employ
-animated content to depict sign language representations of the same content
-as expressed by a Timed Text <a href="#terms-document-instance">document instance</a>. This use case is not
-explicitly addressed by TTML mechanisms, but may be addressed by some
-external multimedia integration technology, such as SMIL.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>In previous drafts of this specification, TTML was referred to as DFXP (Distribution
-Format Exchange Profile). This latter term is retained for historical reasons in
-certain contexts, such as profile names and designators, and the short name
-<code>ttaf1-dfxp</code> used in URLs to refer to this specification.</p></div><div class="div2">
-<h3><a id="model"></a>1.1 System Model</h3><p>Use of TTML is intended to function in a wider context of Timed Text
-Authoring and Distribution mechanisms that are based upon the system
-model depicted in <a href="#model-graphic"><b>Figure 1 – System Model</b></a>, wherein the Timed Text Markup Language
-serves as a bidirectional interchange format among a heterogeneous collection of
-authoring systems, and as a unidirectional interchange format to a
-heterogeneous collection of distribution formats after undergoing transcoding
-or compilation to the target distribution formats as required, and where one
-particular distribution format is TTML (labeled as "DFXP" in the figure).</p><a id="model-graphic"></a><table class="example-images"><caption>Figure 1 – System Model</caption><tbody><tr><td><img src="images/model.png" alt="System Model"></td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Revise System Model"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Revise System Model</b></td><td align="right" valign="top">2014-11-27</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Update system model diagram to reflect current and expected usage. Eliminate reference to DFXP.</td></tr></table></div><div class="div2">
-<h3><a id="example"></a>1.2 Document Example</h3><p>A TTML <a href="#terms-document-instance">document instance</a> consists of a <code>tt</code> document element that contains
-a header and a body, where the header specifies document level metadata, styling
-definitions and layout definitions, and the body specifies text content intermixed
-with references to style and layout information and inline styling and timing information.</p><a id="ttml-example-document-structure"></a><table class="example"><caption>Example Fragment – TTML Document Structure</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head&gt;
-    &lt;metadata/&gt;
-    &lt;styling/&gt;
-    &lt;layout/&gt;
-  &lt;/head&gt;
-  &lt;body/&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p>Document level metadata may specify a document title, description,
-and copyright information. In addition, arbitrary metadata drawn from
-other namespaces may be specified.</p><a id="ttml-example-metadata"></a><table class="example"><caption>Example Fragment – TTML Metadata</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-  &lt;ttm:title&gt;Timed Text TTML Example&lt;/ttm:title&gt;
-  &lt;ttm:copyright&gt;The Authors (c) 2006&lt;/ttm:copyright&gt;
-&lt;/metadata&gt;
-</pre></div>
-</td></tr></tbody></table><p>Styling information may be specified in the form of style specification
-definitions that are referenced by layout and content information,
-specified inline with content information, or both.</p><p>In <a href="#ttml-example-styling"><b>Example Fragment – TTML Styling</b></a>, four style sets of specifications
-are defined, with one set serving as a collection of default styles.</p><a id="ttml-example-styling"></a><table class="example"><caption>Example Fragment – TTML Styling</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;styling xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;!-- s1 specifies default color, font, and text alignment --&gt;
-  &lt;style xml:id="s1"
-    tts:color="white"
-    tts:fontFamily="proportionalSansSerif"
-    tts:fontSize="22px"
-    tts:textAlign="center"
-  /&gt;
-  &lt;!-- alternative using yellow text but otherwise the same as style s1 --&gt;
-  &lt;style xml:id="s2" style="s1" tts:color="yellow"/&gt;
-  &lt;!-- a style based on s1 but justified to the right --&gt;
-  &lt;style xml:id="s1Right" style="s1" tts:textAlign="end" /&gt;     
-  &lt;!-- a style based on s2 but justified to the left --&gt;
-  &lt;style xml:id="s2Left" style="s2" tts:textAlign="start" /&gt;
-&lt;/styling&gt;
-</pre></div>
-</td></tr></tbody></table><p>Layout information defines one or more regions into which content
-is intended to be presented. A region definition may reference one or
-more sets of style specifications in order to permit content flowed in the
-region to inherit from these styles.
-In <a href="#ttml-example-layout"><b>Example Fragment – TTML Layout</b></a>, the region definition makes
-reference to style specification <code>s1</code> augmented by specific inline
-styles which, together, allow content flowed into the region to inherit
-from the region's styles (in the case
-that a style is not already explicitly specified on content or inherited
-via the content hierarchy.)</p><a id="ttml-example-layout"></a><table class="example"><caption>Example Fragment – TTML Layout</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;layout xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;region xml:id="subtitleArea"
-    style="s1"
-    tts:extent="560px 62px"
-    tts:padding="5px 3px"
-    tts:backgroundColor="black"
-    tts:displayAlign="after"
-  /&gt;
-&lt;/layout&gt;  
-</pre></div>
-</td></tr></tbody></table><p>The content of a <a href="#terms-document-instance">document instance</a> is expressed in its
-body, which is organized in terms of block and inline text elements.
-The hierarchical organization of content elements serves a primary role in
-determining both spatial and temporal relationships. For example, in
-<a href="#ttml-example-body"><b>Example Fragment – TTML Body</b></a>, each paragraph (<code>p</code> element)
-is flowed into its target region in the specified lexical order; furthermore,
-the active time interval of each paragraph is timed in accordance to its
-parent or sibling according to the applicable time containment semantics —
-in this case, the division parent is interpreted (by default) as a parallel time
-container.</p><a id="ttml-example-body"></a><table class="example"><caption>Example Fragment – TTML Body</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;body region="subtitleArea"&gt;
-  &lt;div&gt;
-    &lt;p xml:id="subtitle1" begin="0.76s" end="3.45s"&gt;
-      It seems a paradox, does it not,
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle2" begin="5.0s" end="10.0s"&gt;
-      that the image formed on&lt;br/&gt;
-      the Retina should be inverted?
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle3" begin="10.0s" end="16.0s" style="s2"&gt;
-      It is puzzling, why is it&lt;br/&gt;
-      we do not see things upside-down?
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle4" begin="17.2s" end="23.0s"&gt;
-      You have never heard the Theory,&lt;br/&gt;
-      then, that the Brain also is inverted?
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle5" begin="23.0s" end="27.0s" style="s2"&gt;
-      No indeed! What a beautiful fact!
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle6a" begin="28.0s" end="34.6s" style="s2Left"&gt;
-      But how is it proved?
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle6b" begin="28.0s" end="34.6s" style="s1Right"&gt;
-      Thus: what we call
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle7" begin="34.6s" end="45.0s" style="s1Right"&gt;
-      the vertex of the Brain&lt;br/&gt;
-      is really its base
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle8" begin="45.0s" end="52.0s" style="s1Right"&gt;
-      and what we call its base&lt;br/&gt;
-      is really its vertex,
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle9a" begin="53.5s" end="58.7s"&gt;
-      it is simply a question of nomenclature.
-    &lt;/p&gt;
-    &lt;p xml:id="subtitle9b" begin="53.5s" end="58.7s" style="s2"&gt;
-      How truly delightful!
-    &lt;/p&gt;
-  &lt;/div&gt;    
-&lt;/body&gt;
-</pre></div>
-</td></tr></tbody></table><p>The first subtitle <a href="#ttml-example-subtitle-1"><b>Subtitle 1 – Time Interval [0.76, 3.45)</b></a> is
-presented during the time interval 0.76 to 3.45 seconds.
-This
-subtitle inherits its font family, font size,
-foreground color, and text alignment from the region into which it is
-presented. Since no region is explicitly specified on the paragraph,
-the nearest ancestor that specifies a region determines the
-targeted region. Note also that content is presented
-at the bottom (after edge) of the containing region due to the <code>tts:displayAlign="after"</code>
-being specified on the region definition.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The notation "[<em>X</em>,<em>Y</em>]" denotes a closed
-interval from <em>X</em> to <em>Y</em>, including
-<em>X</em> and <em>Y</em>;
-"[<em>X</em>,<em>Y</em>)" denotes a right half-open
-interval from <em>X</em> to <em>Y</em>, including
-<em>X</em> but not including <em>Y</em>;
-"(<em>X</em>,<em>Y</em>]" denotes a left half-open
-interval from <em>X</em> to <em>Y</em>, not including
-<em>X</em> but including <em>Y</em>;
-"(<em>X</em>,<em>Y</em>)" denotes an open
-interval from <em>X</em> to <em>Y</em>, not including
-<em>X</em> or <em>Y</em>.
-</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>In this example, the <code>p</code> element is used as a presentational
-element rather than as a semantic element, i.e., as a linguistic paragraph.
-It is up to an author to determine which TTML elements are used to convey
-the intended meaning. For instance, this example could be written to use
-timing on <code>span</code> elements in order to preserve the integrity of
-semantic paragraphs.</p></div><a id="ttml-example-subtitle-1"></a><table class="example-images"><caption>Subtitle 1 – Time Interval [0.76, 3.45)</caption><tbody><tr><td><img src="images/subtitle1.png" alt="Subtitle 1"></td></tr></tbody></table><p>The second subtitle continues with the default style, except that it contains
-two lines of text with an intervening author-specified line break. Note the effects of
-the use of <code>tts:textAlign="center"</code> to specify the paragraph's alignment
-in the inline progression direction.</p><a id="ttml-example-subtitle-2"></a><table class="example-images"><caption>Subtitle 2 – Time Interval [5.0, 10.0)</caption><tbody><tr><td><img src="images/subtitle2.png" alt="Subtitle 2"></td></tr></tbody></table><p>The third subtitle continues, using a variant style which overrides the default style's
-foreground color with a different color.</p><a id="ttml-example-subtitle-3"></a><table class="example-images"><caption>Subtitle 3 – Time Interval [10.0, 16.0)</caption><tbody><tr><td><img src="images/subtitle3.png" alt="Subtitle 3"></td></tr></tbody></table><p>The fourth subtitle reverts to the default style.</p><a id="ttml-example-subtitle-4"></a><table class="example-images"><caption>Subtitle 4 – Time Interval [17.2, 23.0)</caption><tbody><tr><td><img src="images/subtitle4.png" alt="Subtitle 4"></td></tr></tbody></table><p>The fifth subtitle continues, again using a variant style which
-overrides the default style's foreground color with a different color.</p><a id="ttml-example-subtitle-5"></a><table class="example-images"><caption>Subtitle 5 – Time Interval [23.0, 27.0)</caption><tbody><tr><td><img src="images/subtitle5.png" alt="Subtitle 5"></td></tr></tbody></table><p>During the next active time interval, two distinct subtitles are simultaneously active, with
-the paragraphs expressing each subtitle using different styles that override color and paragraph
-text alignment of the default style. Note that the flow order is determined by the lexical
-order of elements as they appear in the content hierarchy.</p><a id="ttml-example-subtitle-6"></a><table class="example-images"><caption>Subtitles 6a and 6b – Time Interval [28.0, 34.6)</caption><tbody><tr><td><img src="images/subtitle6.png" alt="Subtitles 6a and 6b"></td></tr></tbody></table><p>The next subtitle is specified in a similar manner using
-a style override to give the paragraph right (end) justification in the
-inline progression direction.</p><a id="ttml-example-subtitle-7"></a><table class="example-images"><caption>Subtitle 7 – Time Interval [34.6, 45.0)</caption><tbody><tr><td><img src="images/subtitle7.png" alt="Subtitles 7a and 7b"></td></tr></tbody></table><p>The eighth subtitle uses the same style override as the previous
-subtitle in order to maintain the right (end) justification of the
-paragraph.</p><a id="ttml-example-subtitle-8"></a><table class="example-images"><caption>Subtitle 8 – Time Interval [47.3, 49.0)</caption><tbody><tr><td><img src="images/subtitle8.png" alt="Subtitle 8"></td></tr></tbody></table><p>During the final (ninth) active time interval, two distinct
-subtitles are again simultaneously active, but with a different
-style applied to the second paragraph to override the default color.
-Note that the flow order is determined by the lexical order of
-elements as they appear in the content hierarchy.</p><a id="ttml-example-subtitle-9"></a><table class="example-images"><caption>Subtitles 9a and 9b – Time Interval [53.5, 58.7)</caption><tbody><tr><td><img src="images/subtitle9.png" alt="Subtitles 9a and 9b"></td></tr></tbody></table><p>The examples shown above demonstrate the primary types of information that may
-be authored using TTML: metadata, styling, layout, timing, and content. In typical cases,
-styling and layout information are separately specified in a <a href="#terms-document-instance">document instance</a>. Content information
-is expressed in a hierarchical fashion that embodies the organization of both spatial (flow) and
-timing information. Content makes direct or indirect references to styling and layout information
-and may specify inline overrides to styling.</p></div></div><div class="div1">
-<h2><a id="definitions"></a>2 Definitions</h2><div class="div2">
-<h3><a id="acronyms"></a>2.1 Acronyms</h3><table class="acronyms" summary="Glossary List"><tr><td class="label"><b>DFXP</b></td><td class="def"><p>Distribution Format Exchange Profile</p></td></tr><tr><td class="label"><b>ISD</b></td><td class="def"><p>Intermediate Synchronic Document</p></td></tr><tr><td class="label"><b>TT</b></td><td class="def"><p>Timed Text</p></td></tr><tr><td class="label"><b>TTML</b></td><td class="def"><p>Timed Text Markup Language</p></td></tr><tr><td class="label"><b>TTAF</b></td><td class="def"><p>Timed Text Authoring Format</p></td></tr><tr><td class="label"><b>TTWG</b></td><td class="def"><p>Timed Text Working Group</p></td></tr></table></div><div class="div2">
-<h3><a id="terms"></a>2.2 Terminology</h3><dl><dt class="label"><a id="terms-abstract-document-instance"></a>[abstract document instance]</dt><dd><p>An instance of an abstract data set as represented by a
-<a href="#terms-reduced-xml-infoset">reduced xml infoset</a>.</p></dd><dt class="label"><a id="terms-abstract-document-type"></a>[abstract document type]</dt><dd><p>A set of constraints that defines a class of <em>XML Information
-Sets</em> <a href="#infoset">[XML InfoSet]</a>.</p></dd><dt class="label"><a id="terms-anonymous-profile"></a>[anonymous profile]</dt><dd><p>See <a href="#terms-undesignated-profile">undesignated profile</a>.</p></dd><dt class="label"><a id="terms-attribute-information-item"></a>[attribute information item]</dt><dd><p>Each specified or defaulted attribute  of an XML document corresponds with an attribute information
-item as defined by <a href="#infoset">[XML InfoSet]</a>, §2.3.</p></dd><dt class="label"><a id="terms-audio-defining-context"></a>[audio defining context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element is specified to serve as
-a sharable definition to be referenced by another <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element
-in an <a href="#terms-audio-presentation-context">audio presentation context</a>.</p></dd><dt class="label"><a id="terms-audio-presentation-context"></a>[audio presentation context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element is specified for the
-purpose of being presented (rendered). Such an <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element
-may specify the audio data inline by using a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element within
-a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element child, or it may reference another
-<a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element specified in a 
-<a href="#terms-audio-definition-context">audio definition context</a>, or it may do both.</p></dd><dt class="label"><a id="terms-audio-resource"></a>[audio resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> that contains coded or unencoded audio samples.</p></dd><dt class="label"><a id="terms-authoring-viewport"></a>[authoring viewport]</dt><dd><p>A <a href="#terms-viewport">viewport</a> employed at authoring (content encoding) time.</p></dd><dt class="label"><a id="terms-baseline-profile"></a>[baseline profile]</dt><dd><p>A <a href="#terms-profile">profile</a> referenced by the <code>use</code> attribute of a <code>ttp:profile</code> element,
-which serves as a baseline (initial) set of specifications with which to populate the referencing profile.</p></dd><dt class="label"><a id="terms-block-display"></a>[block display]</dt><dd><p>Block display is a set of layout semantics that may be applied to a <a href="#terms-content-element">content element</a> in
-certain contexts, wherein child areas are composed sequentially in the block progression direction. In <a href="#css2">[CSS2]</a>,
-block display is indicated when a CSS <code>display</code> property with the value <code>block</code> is applied to a
-<a href="#terms-content-element">content element</a> during presentation processing. In <a href="#xsl11">[XSL 1.1]</a>, a block display
-occurs when composing a <code>fo:block</code> element.</p></dd><dt class="label"><a id="terms-character-information-item"></a>[character information item]</dt><dd><p>Each data character appearing in an XML document corresponds with a character information
-item as defined by <a href="#infoset">[XML InfoSet]</a>, §2.6.</p></dd><dt class="label"><a id="terms-chunked-data-embedding"></a>[chunked data embedding]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element that directly embeds a representation of the actual bytes
-of an <a href="#terms-embedded-data-resource">embedded data resource</a> by making use of a
-child <a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a> element.</p></dd><dt class="label"><a id="terms-computed-cell-size"></a>[computed cell size]</dt><dd><p>The size (extent) of a cell computed by dividing the width of the <a href="#terms-root-container-region">root container region</a>
-by the column count, i.e., the number of cells in the horizontal axis, and by dividing
-the height of the <a href="#terms-root-container-region">root container region</a> by the row count, i.e., the number of cells in the vertical
-axis, where the column and row counts are determined by the <code>ttp:cellResolution</code> parameter attribute.</p></dd><dt class="label"><a id="terms-content-element"></a>[content element]</dt><dd><p>Any of the element types defined by the <a href="#element-vocab-type-content">Content Module</a>.</p></dd><dt class="label"><a id="terms-content-image"></a>[content image]</dt><dd><p>An <a href="#terms-image-resource">image resource</a> that contains semantically significant content, e.g., a raster image
-representing the rendering of a caption.</p></dd><dt class="label"><a id="terms-content-processor"></a>[content processor]</dt><dd><p>A processing system capable of importing (receiving) Timed Text Markup Language
-content for the purpose of transforming, presenting, or otherwise processing the content.</p></dd><dt class="label"><a id="terms-content-profile"></a>[content profile]</dt><dd><p>A collection of <a href="#terms-feature">features</a> and <a href="#terms-extension">extensions</a> that must not, must, or may be employed by
-Timed Text Markup Language content.</p><p></p></dd><dt class="label"><a id="terms-content-region"></a>[content region]</dt><dd><p>A logical region into which rendered content is placed when modeling or
-performing presentation processing.</p><table border="1" class="ednote" summary="Editorial note: Content Region vs Region"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Content Region vs Region</b></td><td align="right" valign="top">2014-12-10</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Clean up terminology regarding content region vs region, which difference is vague at best.</td></tr></table><p></p></dd><dt class="label"><a id="terms-data-binding-context"></a>[data binding context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-data"><code>data</code></a> element is specified for the
-purpose of semantic binding (association). Such a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element
-may specify the data inline by using a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element within
-a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element child, or it may reference another
-<a href="#embedded-content-vocabulary-data"><code>data</code></a> element specified in a 
-<a href="#terms-data-definition-context">data definition context</a>, or it may do both. No presentation (rendering)
-semantics are implied by the mere presence of a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element in this (or any) context.</p></dd><dt class="label"><a id="terms-data-binding-context-for-metadata"></a>[data binding context for metadata]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element the parent of which is a
-<a href="#metadata-vocabulary-metadata"><code>metadata</code></a> element.</p></dd><dt class="label"><a id="terms-data-binding-context-for-source"></a>[data binding context for source]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element the parent of which is a
-<a href="#embedded-content-vocabulary-source"><code>source</code></a> element.</p></dd><dt class="label"><a id="terms-data-defining-context"></a>[data defining context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-data"><code>data</code></a> element is specified to serve as
-a sharable definition to be referenced by another <a href="#embedded-content-vocabulary-data"><code>data</code></a> element
-in an <a href="#terms-data-binding-context">data binding context</a>, namely, a
-<a href="#embedded-content-vocabulary-data"><code>data</code></a> element the parent of which is a
-<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element.</p></dd><dt class="label"><a id="terms-data-element"></a>[data element]</dt><dd><p>Any of the element types defined by the <a href="#element-vocab-type-data">Data Module</a>.</p></dd><dt class="label"><a id="terms-data-resource"></a>[data resource]</dt><dd><p>An arbitrary data resource represented or referenced using a <a href="#terms-data-element">data element</a>. For example,
-a data resource may be used to embed or refer to an audio clip, a font, an image, or arbitrary application data in a
-<a href="#terms-timed-text-content-document-instance">timed text content document instance</a>.</p></dd><dt class="label"><a id="terms-default-profile"></a>[default processor profile]</dt><dd><p>A default <a href="#terms-processor-profile">processor profile</a> used to compute an
-<a href="#terms-effective-processor-profile">effective processor profile</a> in the absence of a declared or inferred
-<a href="#terms-processor-profile">processor profile</a>, where this default processor profile is determined by
-the <a href="#semantics-procedure-construct-default-processor-profile"><span class="strong">construct default processor profile</span></a>
-procedure.</p></dd><dt class="label"><a id="terms-default-region"></a>[default region]</dt><dd><p>A default <a href="#terms-out-of-line-region">out-of-line region</a> that is implied in the absence of
-an explicitly specified out-of-line <a href="#layout-vocabulary-region"><code>region</code></a> element, i.e.,
-when no <a href="#layout-vocabulary-region"><code>region</code></a> element is specified as a child of
-a <a href="#layout-vocabulary-layout"><code>layout</code></a> element.</p></dd><dt class="label"><a id="terms-designated-profile"></a>[designated profile]</dt><dd><p>A <a href="#terms-profile">profile</a> that is associated with a <a href="#terms-profile-designator">profile designator</a> by
-means of a <code>designator</code> attribute or prose text in a specification of profile.</p></dd><dt class="label"><a id="terms-display-aspect-ratio"></a>[display aspect ratio]</dt><dd><p>The ratio between the horizontal dimension and vertical dimension of a displayed image, video frame,
-viewport or region, display device, etc. Equal to the product of <a href="#terms-storage-aspect-ratio">storage aspect ratio</a>
-and <a href="#terms-pixel-aspect-ratio">pixel aspect ratio</a>.</p></dd><dt class="label"><a id="terms-display-region-target"></a>[display region target]</dt><dd><p>A <a href="#terms-viewport">viewport</a> targeted to a rectangular region of a display device, i.e., not in full-screen mode.</p></dd><dt class="label"><a id="terms-display-target"></a>[display target]</dt><dd><p>A <a href="#terms-viewport">viewport</a> targeted to a display device as a whole, i.e., in full-screen mode.</p></dd><dt class="label"><a id="terms-document-coordinate-space"></a>[document coordinate space]</dt><dd><p></p><table border="1" class="ednote" summary="Editorial note: Document Coordinate Space Definition"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Document Coordinate Space Definition</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Either define or express in terms of (some) viewport.</td></tr></table><p></p></dd><dt class="label"><a id="terms-document-instance"></a>[document instance]</dt><dd><p>A <a href="#terms-timed-text-document-instance">timed text document instance</a>.</p></dd><dt class="label"><a id="terms-document-interchange-context"></a>[document interchange context]</dt><dd><p>The implied context or environment external to a <a href="#terms-content-processor">content processor</a> in
-which document interchange occurs, and in which out-of-band protocols or specifications
-may define certain behavioral defaults, such as an implied profile.</p></dd><dt class="label"><a id="terms-document-processing-context"></a>[document processing context]</dt><dd><p>The implied context or environment internal to a <a href="#terms-content-processor">content processor</a> in
-which document processing occurs, and in which out-of-band protocols or specifications
-may define certain behavioral defaults, such as the establishment or creation of a
-<a href="#terms-synthetic-document-syncbase">synthetic document syncbase</a>.</p></dd><dt class="label"><a id="terms-dot-pitch"></a>[dot pitch]</dt><dd><p>Depending upon display device technology, the distance between holes in the shadow mask, the distance between wires in the aperture grill,
-the distance between sub-pixels of the same color, etc.</p></dd><dt class="label"><a id="terms-effective-content-profile"></a>[effective content profile]</dt><dd><p>The <a href="#terms-content-profile">content profile</a> computed from the set of all <a href="#terms-content-profile">content profiles</a>
-explicitly or implicitly referenced by or assigned to a TTML <a href="#terms-document-instance">document instance</a> after applying any
-explicit or implicit profile and profile specification combination methods. When performing validation on a given <a href="#terms-document-instance">document instance</a>,
-then this validation is performed by making use of a document's <a href="#terms-effective-content-profile">effective content profile</a>.</p></dd><dt class="label"><a id="terms-effective-processor-profile"></a>[effective processor profile]</dt><dd><p>The <a href="#terms-processor-profile">processor profile</a> computed from the set of all <a href="#terms-processor-profile">processor profiles</a>
-explicitly or implicitly referenced by or assigned to a TTML <a href="#terms-document-instance">document instance</a> after applying any
-explicit or implicit profile and profile specification combination methods. When determining if a <a href="#terms-content-processor">content processor</a>
-can or cannot process a given <a href="#terms-document-instance">document instance</a>, then this determination is performed
-by making use of a document's <a href="#terms-effective-processor-profile">effective processor profile</a>.</p></dd><dt class="label"><a id="terms-element-information-item"></a>[element information item]</dt><dd><p>Each element appearing in an XML document corresponds with an element information
-item as defined by <a href="#infoset">[XML InfoSet]</a>, §2.2.</p></dd><dt class="label"><a id="terms-embedded-content-element"></a>[embedded content element]</dt><dd><p>Any of the element types defined by the <a href="#element-vocab-type-audio">Audio Module</a>,
-<a href="#element-vocab-type-data">Data Module</a>,
-<a href="#element-vocab-type-font">Font Module</a>, or
-<a href="#element-vocab-type-image">Image Module</a>.</p></dd><dt class="label"><a id="terms-embedded-data-resource"></a>[embedded data resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> embedded in a
-<a href="#terms-timed-text-content-document-instance">timed text content document instance</a>, represented by means of
-a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element, whether or not that
-<a href="#embedded-content-vocabulary-data"><code>data</code></a> element represents the actual bytes of the <a href="#terms-data-resource">data resource</a>
-or refers to an <a href="#terms-external-data-resource">external data resource</a>
-</p></dd><dt class="label"><a id="terms-enclosing-document-instance"></a>[enclosing document instance]</dt><dd><p>The <a href="#terms-document-instance">document instance</a> that encloses or otherwise contains
-an enclosed feature or component.</p></dd><dt class="label"><a id="terms-exchange-profile"></a>[exchange profile]</dt><dd><p>A profile of content that serves a set of needs for content interchange.</p></dd><dt class="label"><a id="terms-extension"></a>[extension]</dt><dd><p>A syntactic or semantic expression or capability that is defined and
-labeled (using a extension designation) in another (public or private)
-specification.</p></dd><dt class="label"><a id="terms-extension-specification"></a>[extension specification]</dt><dd><p>A specification of a constraint or requirement that relates to an
-<a href="#terms-extension">extension</a>, typically expressed by
-an <a href="#profile-vocabulary-extension"><code>ttp:extension</code></a> element.</p></dd><dt class="label"><a id="terms-external-data-resource"></a>[external data resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> external to a
-<a href="#terms-timed-text-content-document-instance">timed text content document instance</a>, referenced by means
-of a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element or a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute
-of a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element or <a href="#terms-embedded-content-element">embedded content element</a>.</p></dd><dt class="label"><a id="terms-external-source"></a>[external source]</dt><dd><p>Either (1) a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element or a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute
-that refers to an <a href="#terms-external-data-resource">external data resource</a> or (2) the referenced
-<a href="#terms-external-data-resource">external data resource</a>.</p></dd><dt class="label"><a id="terms-feature"></a>[feature]</dt><dd><p>A syntactic or semantic expression or capability that is defined and
-labeled (using a feature designation) in this specification (or a past or
-future revision of this specification).</p></dd><dt class="label"><a id="terms-feature-specification"></a>[feature specification]</dt><dd><p>A specification of a constraint or requirement that relates to an
-<a href="#terms-feature">feature</a>, typically expressed by
-an <a href="#profile-vocabulary-feature"><code>ttp:feature</code></a> element.</p></dd><dt class="label"><a id="terms-forced-subtitle"></a>[forced subtitle]</dt><dd><p>A subtitle (or caption) that is intended to always be displayed even if subtitles (captions) are not enabled. Forced subtitles (captions)
-are used to prevent open captioning of, i.e., burning in, subtitles (captions) related to foreign or alien language or translation of text
-that appears in media, such as in a sign.</p></dd><dt class="label"><a id="terms-font-defining-context"></a>[font defining context]</dt><dd><p>The context in which a <a href="#embedded-content-vocabulary-font"><code>font</code></a> element is specified to serve as
-a sharable definition to be referenced indirectly by a <a href="#terms-font-selection-process">font selection process</a>.</p></dd><dt class="label"><a id="terms-font-selection-process"></a>[font selection process]</dt><dd><p>An internal process used by a <a href="#terms-presentation-processor">presentation processor</a> which purpose is to select
-a set of author defined fonts and platform fonts for use during layout and presentation processing, where input parameters to this
-process include the computed values of font related properties, the capabilities of individual fonts, and the text content being presented.</p></dd><dt class="label"><a id="terms-font-resource"></a>[font resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> that contains font information, such as character to glyph mapping data, glyph outlines or images,
-glyph metrics, and other data used in the character to glyph mapping and rendering process.</p></dd><dt class="label"><a id="terms-fragment-identifier"></a>[fragment identifier]</dt><dd><p>A syntactic expression that adheres to the fragment identifer syntax defined by <a href="#uri">[URI]</a>,
-Section 4.1.</p></dd><dt class="label"><a id="terms-image-defining-context"></a>[image defining context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element is specified to serve as
-a sharable definition to be referenced by another <a href="#embedded-content-vocabulary-image"><code>image</code></a> element
-in an <a href="#terms-image-presentation-context">image presentation context</a>.</p></dd><dt class="label"><a id="terms-image-presentation-context"></a>[image presentation context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element is specified for the
-purpose of being presented (rendered). Such an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element
-may specify the image data inline by using a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element within
-a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element child, or it may reference another
-<a href="#embedded-content-vocabulary-image"><code>image</code></a> element specified in a 
-<a href="#terms-image-definition-context">image definition context</a>, or it may do both.</p></dd><dt class="label"><a id="terms-image-resource"></a>[image resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> that contains a raster image.</p></dd><dt class="label"><a id="terms-implied-inline-region"></a>[implied inline region]</dt><dd><p>An anonymous (unidentified) <a href="#terms-inline-region">inline region</a> that is implied in the context of a block level
-<a href="#terms-content-element">content element</a>
-due the presence of a <a href="#style-attribute-extent"><code>tts:extent</code></a> or <a href="#style-attribute-origin"><code>tts:origin</code></a>
-style attribute on the <a href="#terms-content-element">content element</a>.</p></dd><dt class="label"><a id="terms-inline-animation"></a>[inline animation]</dt><dd><p>An <a href="#animation-vocabulary-animate"><code>animate</code></a> or <a href="#animation-vocabulary-set"><code>set</code></a> element
-that is defined inline as an immediate child of
-a <a href="#terms-content-element">content element</a> or <a href="#layout-vocabulary-region"><code>region</code></a> element associated with the animation.
-There is a one-to-one relation between
-an inline animation element and its parent <a href="#terms-content-element">content element</a> or <a href="#layout-vocabulary-region"><code>region</code></a> element.</p></dd><dt class="label"><a id="terms-inline-block-display"></a>[inline block display]</dt><dd><p>Inline block display is a set of layout semantics that may be applied to a <a href="#terms-content-element">content element</a> in
-certain contexts, wherein a generated block area is treated as an an atomic area to be composed in an inline layout context, i.e., the block
-area is treated as if it were itself an inline area when considered externally, but as a block area which considered internally. In <a href="#css2">[CSS2]</a>,
-inline block display is indicated when a CSS <code>display</code> property with the value <code>inline-block</code> is applied to a
-<a href="#terms-content-element">content element</a> during presentation processing. In <a href="#xsl11">[XSL 1.1]</a>, an inline block display
-occurs when block content appears in an inline content context, e.g., when a <code>fo:block</code> appears as a child of <code>fo:inline</code>.</p></dd><dt class="label"><a id="terms-inline-display"></a>[inline display]</dt><dd><p>Inline display is a set of layout semantics that may be applied to a <a href="#terms-content-element">content element</a> in
-certain contexts, wherein child areas are composed sequentially in the inline progression direction. In <a href="#css2">[CSS2]</a>,
-inline display is indicated when a CSS <code>display</code> property with the value <code>inline</code> is applied to a
-<a href="#terms-content-element">content element</a> during presentation processing. In <a href="#xsl11">[XSL 1.1]</a>, an inline display
-occurs when composing a <code>fo:inline</code> element.</p></dd><dt class="label"><a id="terms-inline-region"></a>[inline region]</dt><dd><p>A <a href="#terms-region">region</a> that is defined in an inline manner with respect to some
-<a href="#terms-content-element">content element</a>  to be selected into (targeted to) the region.
-An inline region is specified either explicitly by a <a href="#layout-vocabulary-region"><code>region</code></a> element child of
-a <a href="#terms-content-element">content element</a> or implicitly by specifying a <a href="#style-attribute-extent">tts:extent</a>
-or <a href="#style-attribute-origin">tts:origin</a> style attribute on a <a href="#terms-content-element">content element</a>.
-There is a one-to-one relation between an inline <a href="#layout-vocabulary-region"><code>region</code></a> element and its
-parent <a href="#terms-content-element">content element</a>. An inline region is assigned its parent element's time interval as its active
-time interval. No <code>region</code> attribute makes reference to an inline region.</p></dd><dt class="label"><a id="terms-intermediate-synchronic-document"></a>[intermediate synchronic document]</dt><dd><p>A <a href="#terms-timed-text-intermediate-document">timed text intermediate document</a> or a
-<a href="#terms-timed-text-intermediate-document-instance">timed text intermediate document instance</a>, according to the context of use,
-where the root (document) element is an <code>isd:isd</code> element, and which represents a
-non-overlapping temporal interval that intersects with the content, styling, layout, and timing of a source
-<a href="#terms-timed-text-content-document">timed text content document</a>.</p></dd><dt class="label"><a id="terms-intermediate-synchronic-document-sequence"></a>[intermediate synchronic document sequence]</dt><dd><p>A <a href="#terms-timed-text-intermediate-document">timed text intermediate document</a> or a
-<a href="#terms-timed-text-intermediate-document-instance">timed text intermediate document instance</a>, according to the context of use,
-where the root (document) element is an <code>isd:sequence</code> element, and which represents a
-sequence of <a href="#terms-intermediate-synchronic-document">intermediate synchronic document</a> instances
-that effectively represent the content, styling, layout, and timing of a source <a href="#terms-timed-text-content-document">timed text content document</a>.</p></dd><dt class="label"><a id="terms-intermediate-document-syntax"></a>[intermediate document syntax]</dt><dd><p>A formalism for use in the concrete representation of an <a href="#terms-intermediate-synchronic-document-sequence">intermediate synchronic document sequence</a> or
-an <a href="#terms-intermediate-synchronic-document">intermediate synchronic document</a>.</p></dd><dt class="label"><a id="terms-nested-profile"></a>[nested profile]</dt><dd><p>A constituent <a href="#terms-profile">profile</a> of a <a href="#terms-nesting-profile">nesting profile</a>, i.e., one of the
-descendant <code>ttp:profile</code> element(s) of a higher level (ancestor) <code>ttp:profile</code> element. A given <code>ttp:profile</code> may serve
-as both a <a href="#terms-nested-profile">nested profile</a> and a <a href="#terms-nesting-profile">nesting profile</a>.</p></dd><dt class="label"><a id="terms-nesting-profile"></a>[nesting profile]</dt><dd><p>A <a href="#terms-profile">profile</a> defined by making reference to one or more child <code>ttp:profile</code> element(s), wherein a
-profile combination method determines how profile specifications from the multiple child <code>ttp:profile</code> element(s) are combined.</p></dd><dt class="label"><a id="terms-nested-embedded-source"></a>[nested embedded source]</dt><dd><p>A <a href="#embedded-content-vocabulary-source"><code>source</code></a> element that specifies a child 
-<a href="#embedded-content-vocabulary-data"><code>data</code></a> element which embeds the actual bytes of the
-<a href="#terms-embedded-data-resource">embedded data resource</a>, whether by 
-<a href="#terms-simple-data-embedding">simple data embedding</a> or <a href="#terms-chunked-data-embedding">chunked data embedding</a>.</p></dd><dt class="label"><a id="terms-non-content-image"></a>[non-content image]</dt><dd><p>An <a href="#terms-image-resource">image resource</a> that does not contain semantically significant content, e.g., a raster image
-representing a background design, which, if not presented, would not affect the presentation of semntically significant content.</p></dd><dt class="label"><a id="terms-non-nested-embedded-source"></a>[non-nested embedded source]</dt><dd><p>A <a href="#embedded-content-vocabulary-source"><code>source</code></a> element that specifies a child 
-<a href="#embedded-content-vocabulary-data"><code>data</code></a> element which does not embed a representation of the actual bytes of the
-<a href="#terms-embedded-data-resource">embedded data resource</a>.</p></dd><dt class="label"><a id="terms-non-nesting-profile"></a>[non-nesting profile]</dt><dd><p>A <a href="#terms-profile">profile</a> defined without making reference to one or more child <code>ttp:profile</code> element(s); that is,
-by including only child <code>ttp:features</code> and <code>ttp:extensions</code> element(s).</p></dd><dt class="label"><a id="terms-out-of-line-animation"></a>[out-of-line animation]</dt><dd><p>An <a href="#animation-vocabulary-animate"><code>animate</code></a> or <a href="#animation-vocabulary-set"><code>set</code></a> element that is defined out-of-line from
-the <a href="#terms-content-element">content element</a> or <a href="#layout-vocabulary-region"><code>region</code></a> element associated with the animation.
-An out-of-line animation appears as a child of an <a href="#animation-vocabulary-animation"><code>animation</code></a> element in the header
-(<a href="#document-structure-vocabulary-head"><code>head</code></a> element)
-of a <a href="#terms-document-instance">document instance</a>, and specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute
-which value is referenced by an <a href="#animation-attribute-animate"><code>animate</code></a> attribute
-on the associated element to be animated. There is a one-to-many relation between
-a referenced out-of-line animation element and referencing <a href="#terms-content-element">content elements</a> and
-<a href="#layout-vocabulary-region"><code>region</code></a> elements.</p></dd><dt class="label"><a id="terms-out-of-line-region"></a>[out-of-line region]</dt><dd><p>A <a href="#layout-vocabulary-region"><code>region</code></a> element that is defined out-of-line from
-a <a href="#terms-content-element">content element</a> associated with (to be selected into) the region.
-An out-of-line region appears as a child of a <a href="#layout-vocabulary-layout"><code>layout</code></a> element in the header
-(<a href="#document-structure-vocabulary-head"><code>head</code></a> element)
-of a <a href="#terms-document-instance">document instance</a>, and specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute
-which value is referenced by a <a href="#layout-attribute-region"><code>region</code></a> attribute
-on the associated element to be selected into the region. There is a one-to-many relation between
-a referenced out-of-line region element and referencing <a href="#terms-content-element">content elements</a>.
-A <a href="#terms-default-region">default out-of-line region</a> is implied if no
-<a href="#terms-out-of-line-region">out-of-line region</a> is specified explicitly.</p></dd><dt class="label"><a id="terms-pixel-aspect-ratio"></a>[pixel aspect ratio]</dt><dd><p>The ratio between the horizontal dimension and vertical dimension of a displayed pixel. Note that the dimensions of a display pixel may or may not
-correspond to the <a href="#terms-dot-pitch">dot pitch</a> of the display device on which it is rendered.</p></dd><dt class="label"><a id="terms-presentation-context-coordinate-space"></a>[presentation context coordinate space]</dt><dd><p></p><table border="1" class="ednote" summary="Editorial note: Presentation Context Coordinate Space Definition"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Presentation Context Coordinate Space Definition</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Either define or express in terms of (some) viewport.</td></tr></table><p></p></dd><dt class="label"><a id="terms-presentation-processor"></a>[presentation processor]</dt><dd><p>A <a href="#terms-content-processor">content processor</a> which purpose is to layout, format, and render,
-i.e., to present, <a href="#terms-timed-text-markup-language">Timed Text Markup Language</a> content by applying the presentation semantics
-defined in this specification.</p></dd><dt class="label"><a id="terms-presentation-viewport"></a>[presentation viewport]</dt><dd><p>A <a href="#terms-viewport">viewport</a> employed at presentation (content decoding) time.</p><p>Note well that the characteristics of a <a href="#presentation-viewport">presentation viewport</a> may or may not
-match the characteristics of the <a href="#authoring-viewport">authoring viewport</a> used when content was authored (encoded).
-In particular, the <a href="#terms-storage-aspect-ratio">storage aspect ratio</a> and (or) the <a href="#terms-pixel-aspect-ratio">pixel aspect ratio</a>
-of the former may differ from that of the latter.</p></dd><dt class="label"><a id="terms-processor"></a>[processor]</dt><dd><p>See <a href="#terms-content-processor">content processor</a>.</p></dd><dt class="label"><a id="terms-processor-profile"></a>[processor profile]</dt><dd><p>A collection of <a href="#terms-feature">features</a> and <a href="#terms-extension">extensions</a> that must or may be implemented (supported) by
-a content processor.</p></dd><dt class="label"><a id="terms-profile"></a>[profile]</dt><dd><p>A <a href="#terms-content-profile">content profile</a> or <a href="#terms-processor-profile">processor profile</a>.</p></dd><dt class="label"><a id="terms-profile-definition-document"></a>[profile definition document]</dt><dd><p>A <a href="#terms-timed-text-profile-document">timed text profile document</a> or a
-<a href="#terms-timed-text-profile-document-instance">timed text profile document instance</a>, according to the context of use.</p></dd><dt class="label"><a id="terms-profile-designator"></a>[profile designator]</dt><dd><p>An absolute URI used to label or reference an externally defined <a href="#terms-profile">profile</a>, where
-external refers to being external to a <a href="#terms-document-instance">document instance</a>.</p></dd><dt class="label"><a id="terms-profile-fragment-identifier"></a>[profile fragment identifier]</dt><dd><p>A <a href="#terms-fragment-identifier">fragment identifier</a> used to label or reference an internally defined <a href="#terms-profile">profile</a>, where
-internal refers to being internal to a <a href="#terms-document-instance">document instance</a>.</p></dd><dt class="label"><a id="terms-profile-specification"></a>[profile specification]</dt><dd><p>A <a href="#terms-feature-specification">feature specification</a> or an <a href="#terms-extension-specification">extension specification</a>
-or the internal state representation thereof.</p></dd><dt class="label"><a id="terms-region"></a>[region]</dt><dd><p>A logical construct that models authorial intention regarding
-desired or potential presentation processing, and which is represented as
-a rectangular area of a presentation surface into which content
-is composed and rendered during presentation processing.</p></dd><dt class="label"><a id="terms-reduced-xml-infoset"></a>[reduced xml infoset]</dt><dd><p>An XML Information Set <a href="#infoset">[XML InfoSet]</a> that satisfies the
-constraints specify by <a href="#reduced-infoset"><b>B Reduced XML Infoset</b></a>.</p></dd><dt class="label"><a id="terms-related-media-object"></a>[related media object]</dt><dd><p>A (possibly null) media object associated with or otherwise related
-to a <a href="#terms-document-instance">document instance</a>. For example, an aggregate audio/video media
-object for which a <a href="#terms-document-instance">document instance</a> provides caption or subtitle
-information, and with which that <a href="#terms-document-instance">document instance</a> is associated.</p></dd><dt class="label"><a id="terms-related-media-object-region"></a>[related media object region]</dt><dd><p>When a non-null <a href="#terms-related-media-object">related media object</a> exists, the region of this media object,
-expressed in the coordinate system that applies to the <a href="#terms-document-instance">document instance</a> that is associated with the
-related media object.</p><table border="1" class="ednote" summary="Editorial note: Update Definition of Related Media Object Region"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Update Definition of Related Media Object Region</b></td><td align="right" valign="top">2014-12-02</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Untangle definition from use of document coordinate space.</td></tr></table><p></p></dd><dt class="label"><a id="terms-related-media-object-region-target"></a>[related media object region target]</dt><dd><p>A <a href="#terms-viewport">viewport</a> targeted to a <a href="#terms-related-media-object-region">related media object region</a>.</p></dd><dt class="label"><a id="terms-root-container-region"></a>[root container region]</dt><dd><p>A logical region that establishes a coordinate system into which
-<a href="#terms-content-region">content regions</a> are placed and optionally clipped.</p></dd><dt class="label"><a id="terms-root-temporal-extent"></a>[root temporal extent]</dt><dd><p>The temporal extent (interval) defined by the temporal beginning and ending of a <a href="#terms-document-instance">document instance</a>
-in relationship with some external application or presentation context.</p></dd><dt class="label"><a id="terms-simple-data-embedding"></a>[simple data embedding]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element the directly embeds a representation of the actual bytes
-of an <a href="#terms-embedded-data-resource">embedded data resource</a> without making use of a
-child <a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a> element.</p></dd><dt class="label"><a id="terms-smpte-time-code"></a>[smpte time code]</dt><dd><p>A time code whose format and semantics are established by <a href="#smpte12m">[SMPTE 12M]</a>,
-which may be embedded into or otherwise associated with media content, such
-as a broadcast audio/video stream.</p></dd><dt class="label"><a id="terms-sourced-data-embedding"></a>[sourced data embedding]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element that indirectly references the content
-of an <a href="#terms-embedded-data-resource">embedded data resource</a> by making use of a
-child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element.</p></dd><dt class="label"><a id="terms-storage-aspect-ratio"></a>[storage aspect ratio]</dt><dd><p>The ratio between the number of horizontal samples and the number of vertical samples of a two-dimensional
-representation of an image, a video frame, a viewport or region, etc.</p></dd><dt class="label"><a id="terms-synthetic-document-syncbase"></a>[synthetic document syncbase]</dt><dd><p>A document level <a href="http://www.w3.org/TR/2008/REC-SMIL3-20081201/smil30.html#smil-timing-q158">syncbase</a>
-<a href="#smil3">[SMIL 3.0]</a>, § 5.7.1, synthesized or otherwise established by
-the <a href="#terms-document-processing-context">document processing context</a> in accordance with the
-<a href="#terms-related-media-object">related media object</a> or other processing criteria.</p></dd><dt class="label"><a id="terms-synthetic-smpte-document-syncbase"></a>[synthetic smpte document syncbase]</dt><dd><p>A <a href="#terms-synthetic-document-syncbase">synthetic document syncbase</a> constructed from <a href="#terms-smpte-time-code">smpte time code</a>
-values embedded in or associated with the <a href="#terms-related-media-object">related media object</a> or
-otherwise determined by the <a href="#terms-document-processing-context">document processing context</a>.</p></dd><dt class="label"><a id="terms-temporally-active"></a>[temporally active]</dt><dd><p>A syntactic or semantic feature, e.g., an element or the presentation of an element, is
-<em>temporally active</em> when the current time of selected time base intersects with the
-active time interval of the feature.</p></dd><dt class="label"><a id="terms-temporally-active-region"></a>[temporally active region]</dt><dd><p>A <a href="#terms-region">region</a> that is <a href="#terms-temporally-active">temporally active</a>.</p></dd><dt class="label"><a id="terms-timed-text"></a>[timed text]</dt><dd><p>Textual information that is intrinsically or extrinsically
-associated with timing information.</p></dd><dt class="label"><a id="terms-timed-text-authoring-system"></a>[timed text authoring system]</dt><dd><p>A content authoring system capable of importing and exporting
-Timed Text Markup Language content.</p></dd><dt class="label"><a id="terms-timed-text-content-document"></a>[timed text content document]</dt><dd><p>An abstract document that is purported or confirmed to be a
-<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> of
-the <a href="#ttml-content-doctype">TTML Content Document Type</a>.</p></dd><dt class="label"><a id="terms-timed-text-content-document-instance"></a>[timed text content document instance]</dt><dd><p>A concrete realization of a <a href="#terms-timed-text-content-document">timed text content document</a>,
-about which see <a href="#concrete-encoding"><b>A Concrete Encoding</b></a>.</p></dd><dt class="label"><a id="terms-timed-text-document-instance"></a>[timed text document instance]</dt><dd><p>A concrete realization of a
-<a href="#terms-timed-text-markup-language-document">timed text markup language document</a>,
-where  the concrete form is specific to the context of reference.
-Also referred to as a <a href="#terms-document-instance">TTML document instance</a>
-or simply <a href="#terms-document-instance">document instance</a>.</p></dd><dt class="label"><a id="terms-timed-text-intermediate-document"></a>[timed text intermediate document]</dt><dd><p>An abstract document that is purported or confirmed to be a
-<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> of
-the <a href="#ttml-intermediate-doctype">TTML Intermediate Document Type</a>.</p></dd><dt class="label"><a id="terms-timed-text-intermediate-document-instance"></a>[timed text intermediate document instance]</dt><dd><p>A concrete realization of a <a href="#terms-timed-text-intermediate-document">timed text intermediate document</a>,
-about which see <a href="#concrete-encoding"><b>A Concrete Encoding</b></a>.</p></dd><dt class="label"><a id="terms-timed-text-markup-language"></a>[timed text markup language]</dt><dd><p>A content type that represents timed text content, intermediate representations of this content, or profiles of this content or content processors.</p></dd><dt class="label"><a id="terms-timed-text-markup-language-document"></a>[timed text markup language document]</dt><dd><p>An abstract document that is purported or confirmed to be a
-<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a>.</p></dd><dt class="label"><a id="terms-timed-text-profile-document"></a>[timed text profile document]</dt><dd><p>An abstract document that is purported or confirmed to be a
-<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> of
-the <a href="#ttml-profile-doctype">TTML Profile Document Type</a>.</p></dd><dt class="label"><a id="terms-timed-text-profile-document-instance"></a>[timed text profile document instance]</dt><dd><p>A concrete realization of a <a href="#terms-timed-text-profile-document">timed text profile document</a>,
-about which see <a href="#concrete-encoding"><b>A Concrete Encoding</b></a>.</p></dd><dt class="label"><a id="terms-top-level-profile"></a>[top-level profile]</dt><dd><p>A <a href="#terms-profile">profile</a> defined by a <code>ttp:profile</code> element that appears as a child
-of the <code>head</code> element.</p></dd><dt class="label"><a id="terms-transformation-processor"></a>[transformation processor]</dt><dd><p>A <a href="#terms-content-processor">content processor</a> which purpose is to transform or otherwise rewrite
-<a href="#terms-timed-text-markup-language">Timed Text Markup Language</a> content to either <a href="#terms-timed-text-markup-language">Timed Text Markup Language</a>
-or to another (arbitrary) content format. An example of the first is a processor that removes
-or rewrites TTML features so as to conform to a profile of TTML. An example of the latter is
-a processor that translates TTML into a completely different timed text format. Because this
-specification does not otherwise define a target profile or format for transformation processing,
-no further transformation semantics are defined by this specification.</p></dd><dt class="label"><a id="terms-undesignated-profile"></a>[undesignated profile]</dt><dd><p>A <a href="#terms-profile">profile</a> that is not associated with a <a href="#terms-profile-designator">profile designator</a>, and which is
-referred to implicitly in the context of the profile's definition. Also referred to as an <em>anonymous profile</em>.</p></dd><dt class="label"><a id="terms-valid-abstract-document-instance"></a>[valid abstract document instance]</dt><dd><p>An <a href="#terms-abstract-document-instance">abstract document instance</a> which has been assessed for validity
-and found to be valid as defined by <a href="#doctypes"><b>4 Document Types</b></a>.</p></dd><dt class="label"><a id="terms-viewport"></a>[viewport]</dt><dd><p>A logical, rectangular area with respect to which content is encoded or decoded for the purpose of presentation, where such area
-may be employed by or for the authoring or presentation of a <a href="#terms-related-media-object">related media object</a> or
-the <a href="#terms-root-container-region">root container region</a> and its constituent <a href="#terms-region">regions</a>.</p></dd><dt class="label"><a id="terms-viewport-target"></a>[viewport target]</dt><dd><p>An implied or explicit target or mapping of a <a href="#viewport">viewport</a> to some logical or physical entity, of which this
-specification identifies three such targets:
-<a href="#terms-display-target">display target</a>,
-<a href="#terms-display-region-target">display region target</a>, and
-<a href="#terms-related-media-object-region-target">related media object region target</a>.
-</p></dd></dl></div><div class="div2">
-<h3><a id="conventions"></a>2.3 Documentation Conventions</h3><p>Within normative prose in this specification, the words
-<em>may</em>, <em>should</em>, and <em>must</em> are
-defined as follows:</p><dl class="conformance-keywords"><dt class="label">may</dt><dd><p>Conforming documents and/or TTML processors are permitted to,
-but need not behave as described. </p></dd><dt class="label">should</dt><dd><p>Conforming documents and/or TTML processors are strongly
-recommended to, but need not behave as described.</p></dd><dt class="label">must</dt><dd><p>Conforming documents and/or TTML processors are required
-to behave as described; otherwise, they are in error. </p></dd></dl><p>If normative specification language takes an imperative form,
-then it is to be treated as if the term <span class="strong">must</span>
-applies. Furthermore, if normative language takes a declarative form,
-and this language is governed by <span class="strong">must</span>,
-then it is also to be treated as if the term <span class="strong">must</span>
-applies.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, the phrases "treat X as an error" and "consider X
-as an error" are to be read as mandatory requirements in the context of use. Similarly, if the specification
-prose is "X must apply", "X applies", or "X is mandatory", and "X" is further defined as "X is Y and Z",
-then, by transitive closure, this last declarative phrase is to be read as "Y is mandatory" and
-"Z is mandatory" in the context of use.</p></div><p>All normative syntactic definitions of XML representations and
-other related terms are depicted with a light yellow-orange background color
-and labeled as "XML Representation" or "Syntax Representation", such
-as in the following:</p><a id="elt-syntax-example"></a><table class="syntax"><caption>XML Representation – Element Information Item: example</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;example
-  <span class="reqattr">count</span> = <a href="http://www.w3.org/TR/xmlschema-2/#integer">xsd:integer</a>
-  size = (<em>large</em>|<em>medium</em>|<em>small</em>|<em><span class="deprecated">tiny</span></em>|<em><span class="obsoleted">micro</span></em>) : medium&gt;
-  <em>Content:</em> (all | any*)
-&lt;/example&gt;
-</pre></div>
-</td></tr></tbody></table><p>In an XML representation, bold-face attribute names (e.g. <span class="strong">count</span> above) indicate a required attribute
-information item, and the rest are optional. Where an attribute
-information item has an enumerated type definition, the values are
-shown separated by vertical bars, as for <code>size</code> above; if
-there is a default value, it is shown following a colon. Where an
-<a href="#terms-attribute-information-item">attribute information item</a> has a built-in simple type definition
-defined in <a href="#xsd-2">[XML Schema Part 2]</a>, a hyperlink to its definition
-therein is given.</p><p>In an XML representation, the expression <em>{any attribute not in default or any TT namespace}</em> applies
-only to namespace qualified attributes; unqualified attributes are not permitted unless explicitly defined in this specification.</p><p>An information item depicted with a <span class="deprecated">light yellow orange</span> background color is deprecated (e.g.,
-the <span class="deprecated">tiny</span> value of the <code>size</code> attribute shown above).
-An information item that is <span class="deprecated">deprecated</span> may but should not appear in a TTML document instance,
-and a validating processor should report a warning if it does appear.
-An information item depicted with a <span class="obsoleted">light magenta red</span> background color is obsoleted (e.g.,
-the <span class="obsoleted">micro</span> value of the <code>size</code> attribute shown above).
-An information item that is <span class="obsoleted">obsoleted</span> must not appear in a TTML document instance,
-and a validating processor should report an error if it does appear.
-These designations of an item
-are also explicitly called out in specification text.</p><p>The allowed content of the information item is shown as a grammar
-fragment, using the Kleene operators <code>?</code>, <code>*</code>
-and <code>+</code>. Each element name therein is a hyperlink to its
-own illustration.</p><p>The term linear white-space (LWSP) is to be interpreted as a non-empty sequence of
-SPACE (U+0020), TAB (U+0009), CARRIAGE RETURN (U+000D), or LINE FEED (U+000A),
-which corresponds to production [3] <code>S</code> as defined by <a href="#xml10">[XML 1.0]</a>.</p><p>All content of this specification that is not explicitly marked as
-non-normative is considered to be normative. If a section or appendix
-header contains the expression "Non-Normative", then the entirety
-of the section or appendix is considered non-normative.</p><p>All paragraphs marked as a <span class="strong">Note</span> are considered non-normative.</p><p>Example code fragments are depicted with a light blue-green
-background color and labeled as "Example Fragment", such as in
-the following:</p><a id="example-fragment-1"></a><table class="example"><caption>Example Fragment – Sample</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head&gt;
-    &lt;metadata/&gt;
-    &lt;styling/&gt;
-    &lt;layout/&gt;
-  &lt;/head&gt;
-  &lt;body/&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p>Unless specified otherwise, the vocabulary defining sections of this specification define vocabulary in alphabetical order rather than logical order.</p></div></div><div class="div1">
-<h2><a id="conformance"></a>3 Conformance</h2><p>This section specifies the general conformance requirements for
-TTML documents and processors.</p><div class="div2">
-<h3><a id="conformance-content"></a>3.1 Document Conformance</h3><p>A <a href="#terms-timed-text-document-instance">timed text document instance</a> conforms to this specification if the following criteria are
-satisfied:</p><ol class="enumar"><li><p>When transporting a <a href="#terms-document-instance">document instance</a> in a <a href="#terms-document-interchange-context">document interchange context</a> in which a
-Media Type <a href="#media-types">[MIME Media Types]</a> identifies the content type of the interchanged <a href="#terms-document-instance">document instance</a>, then the specified media type is
-<code>application/ttml+xml</code> in conformance with <a href="#xml-media">[XML Media Types]</a> § 7, with which an optional
-<code>profile</code> parameter may appear, the value of which
-conforms to
-a profile designator as
-defined by
-<a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>.</p></li><li><p>The <a href="#terms-document-instance">document instance</a> is or can be represented as a <a href="#terms-reduced-xml-infoset">reduced xml infoset</a>
-as defined by <a href="#reduced-infoset"><b>B Reduced XML Infoset</b></a>.</p></li><li><p>The <a href="#terms-reduced-xml-infoset">reduced xml infoset</a> that
-corresponds to the <a href="#terms-document-instance">document instance</a> is or can
-be associated with one of the <a href="#terms-abstract-document-type">abstract document types</a> defined by
-<a href="#doctypes"><b>4 Document Types</b></a>.</p></li><li><p>The <a href="#terms-reduced-xml-infoset">reduced xml infoset</a> that corresponds to the <a href="#terms-document-instance">document instance</a> is a
-<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> of the associated
-<a href="#terms-abstract-document-type">abstract document type</a>.</p></li><li><p>The <a href="#terms-reduced-xml-infoset">reduced xml infoset</a> satisfies all additional mandatory syntactic and
-semantic constraints defined by this specification. In addition, this infoset
-should satisfy the web content accessibility guidelines specified by
-<a href="#wcag">[WCAG]</a>.</p></li></ol></div><div class="div2">
-<h3><a id="conformance-processor"></a>3.2 Processor Conformance</h3><div class="div3">
-<h4><a id="conformance-generic-processor"></a>3.2.1 Generic Processor Conformance</h4><table border="1" class="ednote" summary="Editorial note: Profile Processing"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Profile Processing</b></td><td align="right" valign="top">2014-05-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add requirement to invoke <span class="strong">abort if unsupported processor profile</span> procedure.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Validation Processing"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Validation Processing</b></td><td align="right" valign="top">2014-05-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add requirement to invoke validation processing procedure. Add and use definition of 'validating processor'.</td></tr></table><p>A TTML <a href="#terms-content-processor">content processor</a> conforms to this specification if the following
-generic processor criteria are
-satisfied:</p><ol class="enumar"><li><p>The processor provides at least one mechanism for notionally
-instantiating a <a href="#terms-reduced-xml-infoset">reduced xml infoset</a>
-representation of a conformant <a href="#terms-document-instance">document instance</a>.</p></li><li><p>If a processor does or can perform validation of a candidate 
-<a href="#terms-document-instance">document instance</a>, then it provides at least one mechanism to
-implicitly or explicitly associate the
-<a href="#terms-reduced-xml-infoset">reduced xml infoset</a> representation
-of a conformant <a href="#terms-document-instance">document instance</a> with one of the
-<em>Abstract Document Types</em> defined by
-<a href="#doctypes"><b>4 Document Types</b></a>.</p></li><li><p>The processor does not <em>a priori</em> reject or abort the
-processing of a conformant <a href="#terms-document-instance">document instance</a>
-unless the processor does not support some required
-(mandatory) feature specified or implied by a TTML profile
-declared to apply to the <a href="#terms-document-instance">document instance</a>.</p></li><li><p>The processor supports all mandatory processing semantics defined by this specification.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The phrase <em>mandatory semantics</em> refers to all explicit use of the conformance
-key phrases <span class="strong">must</span> and <span class="strong">must not</span> as well as any
-declarative statement that can be reasonably inferred from such key phrases. For example, these
-mandatory semantics include support for all features marked as mandatory in <a href="#feature-support"><b>E.2 Feature Support</b></a>.</p></div></li><li><p>If the processor supports some optional processing semantics defined by this specification,
-then it does so in a manner consistent with the defined semantics.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The phrase <em>optional semantics</em> refers to all explicit use of the conformance
-key phrases <span class="strong">should</span>, <span class="strong">should not</span>,
-<span class="strong">may</span>, and <span class="strong">may not</span>,
-as well as any declarative statement that can be reasonably inferred from such key phrases. For example, these
-optional semantics include support for all features marked as optional in <a href="#feature-support"><b>E.2 Feature Support</b></a>.</p></div></li></ol></div><div class="div3">
-<h4><a id="conformance-transformation-processor"></a>3.2.2 Transformation Processor Conformance</h4><p>A TTML <a href="#terms-content-processor">content processor</a> is a conformant TTML <a href="#terms-transformation-processor">transformation processor</a> if
-the following criteria are satisfied:</p><ol class="enumar"><li><p>The processor satisfies all requirements specified by
-<a href="#conformance-generic-processor"><b>3.2.1 Generic Processor Conformance</b></a>.</p></li><li><p>The processor supports the TTML Transformation profile as specified
-by <a href="#profile-ttml2-transformation"><b>G.3 TTML2 Transformation Profile</b></a>.</p></li></ol><table border="1" class="ednote" summary="Editorial note: Mandatory Support for DFXP Transformation Profile"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Mandatory Support for DFXP Transformation Profile</b></td><td align="right" valign="top">2014-07-31</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Should we also require support for DFXP Transformation Profile?</td></tr></table></div><div class="div3">
-<h4><a id="conformance-presentation-processor"></a>3.2.3 Presentation Processor Conformance</h4><p>A TTML <a href="#terms-content-processor">content processor</a> is a conformant TTML <a href="#terms-presentation-processor">presentation processor</a> if
-the following criteria are satisfied:</p><ol class="enumar"><li><p>The processor satisfies all requirements specified by
-<a href="#conformance-generic-processor"><b>3.2.1 Generic Processor Conformance</b></a>.</p></li><li><p>The processor supports the TTML Presentation profile as specified
-by <a href="#profile-ttml2-presentation"><b>G.2 TTML2 Presentation Profile</b></a>.</p></li></ol><table border="1" class="ednote" summary="Editorial note: Mandatory Support for DFXP Presentation Profile"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Mandatory Support for DFXP Presentation Profile</b></td><td align="right" valign="top">2014-07-31</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Should we also require support for DFXP Presentation Profile?</td></tr></table></div></div><div class="div2">
-<h3><a id="claims"></a>3.3 Claims</h3><p>Any claim of compliance with respect to the conformance of a TTML <a href="#terms-document-instance">document instance</a> or
-<a href="#terms-content-processor">content processor</a> must make
-reference to an implementation compliance statement (ICS).</p><p>An implementation compliance statement must identify all mandatory
-and optional features of this specification that are satisfied by the
-document instance or the content processor implementation. In particular, the statement must
-identify the utilized or supported TTML vocabulary profile(s) as
-defined by <a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>, and, if a subset or
-superset profile is used or supported, then what features are excluded
-or included in the subset or superset profile.</p><p>A <a href="#terms-document-instance">document instance</a> for which a compliance claim is made
-must specify
-either (1)
-a <code>ttp:profile</code> attribute on its root
-<code>tt</code>
-element
-as defined by <a href="#profile-attribute-profile"><b>6.2.7 ttp:profile</b></a>
-or (2)
-a <code>ttp:profile</code> element as a child of the
-<code>head</code> element as defined by
-<a href="#profile-vocabulary-profile"><b>6.1.1 ttp:profile</b></a>. In addition, it must specify a
-<code>ttp:version</code> attribute on its root <code>tt</code> element if it requires
-support for a <a href="#terms-feature">feature</a> not defined by <a href="#ttml1">[TTML1]</a>.</p></div></div><div class="div1">
-<h2><a id="doctypes"></a>4 Document Types</h2><p>This section defines the following TTML <em>Abstract Document Types</em>:</p><ul><li><p><a href="#ttml-content-doctype"><b>4.1 TTML Content Document Type</b></a></p></li><li><p><a href="#ttml-intermediate-doctype"><b>4.2 TTML Intermediate Document Type</b></a></p></li><li><p><a href="#ttml-profile-doctype"><b>4.3 TTML Profile Document Type</b></a></p></li></ul><p>Each <a href="#terms-abstract-document-type">abstract document type</a> consists of the following constraints:</p><ul><li><p>a non-empty collection of element types, where each element type consists of a name,
-a (possibly empty) collection of attributes, and a content specification</p></li><li><p>a non-empty collection of element types that may appear as the document element</p></li></ul><p>An <a href="#terms-abstract-document-instance">abstract document instance</a> may be assessed in terms of validity,
-and is considered to be a <a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> if it
-satisfies the following condition: if after</p><ol class="enumar"><li><p>pruning all element information
-items whose names are not members of the collection of element types defined
-by the associated <a href="#terms-abstract-document-type">abstract document type</a>, then</p></li><li><p>pruning character
-information item children from any remaining element in case that all
-character children of the element denote XML whitespace characters and the element's type
-is defined as empty in the associated <a href="#terms-abstract-document-type">abstract document type</a>, and then</p></li><li><p>pruning all attribute
-information items having expanded names such that the namespace URI of the
-expanded names are not listed in <a href="#namespace-vocab-table"><b>Table 5-1 – Namespaces</b></a>,</p></li></ol><p>then the document element is one of the document
-element types permitted by the associated <a href="#terms-abstract-document-type">abstract document type</a>,
-the descendants of the document
-element satisfy their respective element type's content
-specifications, all required attributes are present, and the declared
-value of each attribute satisfies the type declared by the
-associated <a href="#terms-abstract-document-type">abstract document type</a>.</p><div class="issue"><p class="prefix"><a id="issue-362"></a><b>Issue (issue-362):</b></p><p class="prefix"><b>Attribute Forward Compabitility</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/362">http://www.w3.org/AudioVideo/TT/tracker/issues/362</a></p><p>Enhance step (3) to handle forward compatibility of new attributes introduced into TT namespaces.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>While a conformant processor may not <em>a priori</em> reject a
-conformant <a href="#terms-document-instance">document instance</a>, a given <a href="#terms-document-instance">document instance</a> may be
-constrained by the author or authoring tool to satisfy a more
-restrictive definition of validity.</p></div><div class="div2">
-<h3><a id="ttml-content-doctype"></a>4.1 TTML Content Document Type</h3><p>The TTML Content Document Type is an <a href="#terms-abstract-document-type">abstract document type</a> of a profile
-of the Timed Text Markup Language intended to be used for interchange among distribution systems. This document type
-is defined in terms of the element and attribute vocabulary specified in <a href="#vocabulary"><b>5 Vocabulary</b></a>.</p><p>This specification references two types of schemas that may be used to validate a superset/subset
-of <a href="#terms-timed-text-content-document-instance">timed text content document instances</a>:</p><ul><li><p><a href="#ttml-schema-rnc"><b>C.1 Relax NG Compact (RNC) Schema</b></a></p></li><li><p><a href="#ttml-schema-xsd"><b>C.2 XML Schema Definition (XSD) Schema</b></a></p></li></ul><p>The (root) document element of a TTML Content <a href="#terms-document-instance">document instance</a> must be a
-<code>tt</code> element, as defined by <a href="#document-structure-vocabulary-tt"><b>8.1.1 tt</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The schemas referenced by this specification do not validate all syntactic constraints
-defined by this specification, and, as such, represent a superset of conformant
-TTML Content. In particular, performing validation with one of the above
-referenced schemas may result in a <em>false positive</em> indication of validity.
-For example, both the RNC and XSD schemas specify
-that a <code>tts:fontFamily</code> attribute must
-satisfy the <code>xsd:string</code> XSD data type; however, this data type is a superset
-of the values permitted to be used with the <code>tts:fontFamily</code> attribute.</p><p>In addition, the RNC schema may produce a <em>false negative</em>
-indication of validity when using the <code>xml:id</code> attribute with an element in
-a foreign namespace, thus representing a subset of conformant TTML Content. This is
-due to a specific limitation in expressing wildcard patterns involving <code>xsd:ID</code>
-typed attributes in Relax NG schemas. Note that this specification defines the
-formal validity of a <a href="#terms-document-instance">document instance</a> to be based on an <a href="#terms-abstract-document-instance">abstract document instance</a> from
-which all foreign namespace elements and attributes have been removed. Therefore, the
-exceptional reporting of this false negative does not impact the formal assessment
-of <a href="#terms-document-instance">document instance</a> validity.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>A conforming <a href="#conformance-generic-processor">Generic Processor</a> is required to support the ingestion and processing
-of a <a href="#terms-timed-text-content-document">timed text content document</a>.</p></div></div><div class="div2">
-<h3><a id="ttml-intermediate-doctype"></a>4.2 TTML Intermediate Document Type</h3><p>The TTML Intermediate Document Type is an <a href="#terms-abstract-document-type">abstract document type</a> intended
-to be used to represent the content of a
-<a href="#terms-timed-text-content-document">timed text content document</a>
-in such a manner that all discrete animation, styling, and timing information is denoted in
-a non-hierarchical (flat), temporally linear manner. This document type is defined in terms of the element and attribute vocabulary
-specified in <a href="#isd"><b>I Intermediate Document Syntax</b></a> and <a href="#vocabulary"><b>5 Vocabulary</b></a>.</p><p>This specification references two types of schemas that may be used to validate
-<a href="#terms-timed-text-intermediate-document-instance">timed text intermediate document instances</a>:</p><ul><li><p><a href="#ttml-schema-rnc"><b>C.1 Relax NG Compact (RNC) Schema</b></a></p></li><li><p><a href="#ttml-schema-xsd"><b>C.2 XML Schema Definition (XSD) Schema</b></a></p></li></ul><p>The (root) document element of a TTML Intermediate Synchronic <a href="#terms-document-instance">document instance</a> must be an
-<code>isd:sequence</code> or <code>isd:isd</code> element, as defined by <a href="#isd"><b>I Intermediate Document Syntax</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A conforming <a href="#conformance-generic-processor">Generic Processor</a> is not required to support the ingestion or processing
-of a <a href="#terms-timed-text-intermediate-document">timed text intermediate document</a>.</p></div></div><div class="div2">
-<h3><a id="ttml-profile-doctype"></a>4.3 TTML Profile Document Type</h3><p>The TTML Profile Document Type is an <a href="#terms-abstract-document-type">abstract document type</a> intended
-to be used for defining and communicating constraints on the support or use of TTML features or extensions. This document type
-is defined in terms of the element and attribute vocabulary specified in <a href="#vocabulary"><b>5 Vocabulary</b></a>.</p><p>This specification references two types of schemas that may be used to validate
-<a href="#terms-timed-text-profile-document-instance">timed text profile document instances</a>:</p><ul><li><p><a href="#ttml-schema-rnc"><b>C.1 Relax NG Compact (RNC) Schema</b></a></p></li><li><p><a href="#ttml-schema-xsd"><b>C.2 XML Schema Definition (XSD) Schema</b></a></p></li></ul><p>The (root) document element of a TTML Profile <a href="#terms-document-instance">document instance</a> must be a
-<code>ttp:profile</code> element, as defined by <a href="#profile-vocabulary-profile"><b>6.1.1 ttp:profile</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A conforming <a href="#conformance-generic-processor">Generic Processor</a> is recommended, but not required to support the ingestion or processing
-of a <a href="#terms-timed-text-profile-document">timed text profile document</a>. However, a <a href="#terms-content-processor">content processor</a>
-that claims to support the <code>http://www.w3.org/ns/ttml/feature/#profile</code> feature is required to support this (ingestion and processing of
-a <a href="#terms-timed-text-profile-document">timed text profile document</a>).</p></div></div></div><div class="div1">
-<h2><a id="vocabulary"></a>5 Vocabulary</h2><p>This section defines the
-namespaces, profiles, and vocabulary (as an element and attribute
-catalog) of the Timed Text Markup Language (TTML) as follows:</p><ul><li><p><a href="#vocabulary-namespaces"><b>5.1 Namespaces</b></a></p></li><li><p><a href="#vocabulary-profiling"><b>5.2 Profiling</b></a></p></li><li><p><a href="#vocabulary-overview"><b>5.3 Catalog</b></a></p></li></ul><div class="div2">
-<h3><a id="vocabulary-namespaces"></a>5.1 Namespaces</h3><p>The Timed Text Markup Language (TTML) employs a number of
-XML Namespaces <a href="#xmlns10">[XML Namespaces 1.0]</a> for elements and certain
-global attributes. The following table specifies this set of namespaces
-and indicates the default prefix used within this specification and the
-normative URI that denotes each namespace.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In a specific <a href="#terms-document-instance">document instance</a>, it is not required that the default
-prefixes shown below are used. Any prefix or namespace binding that satisfies the constraints
-of XML Namespaces <a href="#xmlns10">[XML Namespaces 1.0]</a>  may be used that is associated with the specified namespace URI.</p></div><a id="namespace-vocab-table"></a><table class="common"><caption>Table 5-1 – Namespaces</caption><col width="30%" span="1"><col span="1"><col span="1"><tbody><tr><th>Name</th><th>Prefix</th><th>Value</th></tr><tr><td>TT</td><td><code>tt:</code></td><td><code>http://www.w3.org/ns/ttml</code></td></tr><tr><td>TT Parameter</td><td><code>ttp:</code></td><td><code>http://www.w3.org/ns/ttml#parameter</code></td></tr><tr><td>TT Style</td><td><code>tts:</code></td><td><code>http://www.w3.org/ns/ttml#styling</code></td></tr><tr><td>TT Metadata</td><td><code>ttm:</code></td><td><code>http://www.w3.org/ns/ttml#metadata</code></td></tr><tr><td>TT Intermediate Synchronic Document</td><td><code>isd:</code></td><td><code>http://www.w3.org/ns/ttml#isd</code></td></tr><tr><td>TT Profile</td><td><em>none</em></td><td><code>http://www.w3.org/ns/ttml/profile/</code></td></tr><tr><td>TT Feature</td><td><em>none</em></td><td><code>http://www.w3.org/ns/ttml/feature/</code></td></tr><tr><td>TT Extension</td><td><em>none</em></td><td><code>http://www.w3.org/ns/ttml/extension/</code></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>If a reference to an element type is used in this specification and the name
-of the element type is not namespace qualified, then the TT Namespace applies.</p><p>If a reference to an attribute is used in this specification and the name
-of the attribute is not namespace qualified, then the attribute is implicitly qualified by
-the element type with which it is used. That is, the attribute resides in the so-called
-<a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/#ns-breakdown"><em>per-element-type namespace partition</em></a>
-<a href="#nsoriginal">[NSOriginal]</a>, the members of which are interpreted in accordance with the definition of the element type on which they appear.</p><p>For certain namespaces defined above, the default prefix
-is specified as <em>none</em> if no XML vocabulary is defined in
-the namespace by this specification (nor expected to be defined in a
-future version of this specification). In such cases, the use of the
-namespace URI is for purposes other than defining XML vocabulary,
-e.g., for designating profiles, features, extensions and for
-dereferencing standard profile definitions.</p></div><p>All TTML Namespaces are <a href="http://www.w3.org/2001/tag/doc/namespaceState#namespacedef"><em>mutable</em></a>
-<a href="#nsstate">[NSState]</a>; all undefined names in these namespaces are reserved for future
-standardization by the W3C.</p></div><div class="div2">
-<h3><a id="vocabulary-profiling"></a>5.2 Profiling</h3><p>This section describes the TTML profiling sub-system and high level requirements that apply to this sub-system. At the end of this section
-appears a sub-section containing examples of profile specifications and examples of how these specifications are referenced and used.</p><div class="div3">
-<h4><a id="vocabulary-profile-introduction"></a>5.2.1 Introduction</h4><p><em>This sub-section is non-normative.</em></p><p>A given profile may be used by a Timed Text Markup Language content author for one of two functions: (1) to declare that a
-<a href="#terms-document-instance">document instance</a> adheres to a collection of constraints on what
-vocabulary is used and how it is used, or (2) to declare that a <a href="#terms-processor">processor</a> must satisfy certain conditions on how
-content is processed. The first of these functions is termed a <a href="#terms-content-profile">content profile</a>, while
-the second is termed a <a href="#terms-processor-profile">processor profile</a>.</p><p>A <a href="#terms-content-profile">content profile</a> is used to allow an author to declare, at authoring time,
-what constraints the author intends to apply to a <a href="#terms-document-instance">document instance</a>. Such a
-declaration permits downstream processors to perform content validation or verification, as well as to guide or limit subsequent
-transformation or editing of content in order to maintain adherence to an author specified content profile. In addition, a
-downstream processor may use a content profile declaration to perform an early determination of its ability to process the features
-implied by the content profile.</p><p>Content profiles are declared by using (1) the <a href="#parameter-attribute-contentProfiles"><code>ttp:contentProfiles</code></a>
-attribute on the root <code>tt</code> element, (2) one or more top-level <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a>
-elements of type <code>content</code>, or (3) a combination of these two mechanisms. If not declared, no content profile is implied.</p><p>A <a href="#terms-processor-profile">processor profile</a> is used to allow an author to declare, at authoring time,
-what processing must be supported when processing a <a href="#terms-document-instance">document instance</a>, such that, if a
-processor is not able to perform the indicated processing, then processing should be aborted. Such a declaration permits downstream
-processors to avoid processing content that cannot be processed in a manner that meets the requirements of the content author.</p><p>Processor profiles are declared by using (1) the <a href="#parameter-attribute-processorProfiles"><code>ttp:processorProfiles</code></a>
-attribute on the root <code>tt</code> element, (2) one or more <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a>
-elements of type <code>processor</code>, or (3) a combination of these two mechanisms.
-If not declared, a processor profile is inferred from a declared content profile or from a
-<a href="#terms-default-profile">default profile</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>It is not a requirement on a conformant <a href="#terms-document-instance">document instance</a> that a processor profile be internally
-declared by use of a <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element or internally referenced by a
-<a href="#parameter-attribute-processorProfiles"><code>ttp:processorProfiles</code></a> attribute. More specifically, it is
-permitted that the <a href="#terms-document-interchange-context">document
-interchange context</a> determines the applicable processor profile through private
-agreement, out-of-band protocol, or common use (between sender and receiver) of a processor profile defined
-by an external specification.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>It is intended that the <code>ttp:processorProfiles</code> attribute be used when
-the author wishes to reference one (or more) of the standard, predefined processor profiles of
-TTML Content, and does not wish to modify (by supersetting or subsetting)
-that profile. This attribute may also be used by an author to indicate the use
-of a non-standard profile, in which case the specified profile designator expresses
-a URI that denotes an externally defined <a href="#terms-profile-definition-document">profile definition document</a>.
-However, it is not required that a conformant TTML <a href="#terms-content-processor">content processor</a> be able
-to dereference such an externally specified profile definition.</p><p>In contrast, it is intended that the <code>ttp:profile</code> element be
-used when the author wishes to make use of a modified predefined profile or
-wishes to include in the <a href="#terms-document-instance">document instance</a> a non-standard profile definition
-not based upon one of the predefined profiles.</p><p>A predefined profile is supersetted by specifying some feature or extension to
-be <code>required</code> (mandatory) that was either not specified in the underlying, baseline
-profile or was specified as <code>optional</code> (voluntary) in the baseline profile.
-A predefined profile is subsetted by specifying some feature or extension to
-be <code>optional</code> (voluntary) that was specified as <code>required</code> (mandatory)
-in the underlying, baseline profile.</p><p>When a baseline profile is modified by subsetting, the resulting, derived profile
-is referred to as a <em>subtractive</em> profile; when modified by supersetting, the result
-is referred to as an <em>additive</em> profile.
-It is also possible to define a derived profile that is simultaneously subtractive
-and additive.</p></div><p>A content author is not limited to using a single profile, but may make reference to multiple profiles of either type, i.e.,
-multiple content profiles and/or multiple processor profiles. When multiple profiles are referenced, their respective specifications
-are combined to form a single effective content profile that applies to the document and a single effective processor profile
-that applies to a processor when processing the document. In addition, an author is not limited to making reference to externally
-defined profiles, but may define one or more profiles inline within a document.</p></div><div class="div3">
-<h4><a id="semantics-profile-examples"></a>5.2.2 Profile Examples</h4><p><em>This sub-section is non-normative.</em></p><table border="1" class="ednote" summary="Editorial note: More profile examples."><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: More profile examples.</b></td><td align="right" valign="top">2014-05-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add more examples depicting new profiling features defined in TTML2.</td></tr></table><p>An example of an author defined
-additive, derived profile of the TTML Presentation
-profile is shown
-below in <a href="#ttml-example-sub-profile"><b>Example Fragment – TTML Additive Profile</b></a>.</p><a id="ttml-example-sub-profile"></a><table class="example"><caption>Example Fragment – TTML Additive Profile</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
- &lt;head&gt;
-   &lt;profile use="ttml2-presentation" xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
-     &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-       &lt;feature value="required"&gt;#fontStyle-italic&lt;/feature&gt;
-     &lt;/features&gt;
-   &lt;/profile&gt;
- &lt;/head&gt;
- &lt;body/&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the baseline profile is declared to be
-the TTML Presentation profile, which is then additively modified by making the
-<code>#fontStyle-italic</code> feature required (rather than
-optional as it is defined
-in <a href="#profile-ttml2-presentation"><b>G.2 TTML2 Presentation Profile</b></a>). Note also the resetting of the
-default XMLNS binding on the <code>profile</code> element to the TT Parameter Namespace.</p></div></div><div class="div3">
-<h4><a id="vocabulary-profile-designators"></a>5.2.3 Profile Designators</h4><table border="1" class="ednote" summary="Editorial note: Reference by designator to internally defined profile."><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Reference by designator to internally defined profile.</b></td><td align="right" valign="top">2014-05-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Handle case where a designator refers to an internally defined profile.</td></tr></table><p>A profile is referenced in one of two ways according to whether the profile is defined externally to the referring document or
-is defined inline within the referring document. When defined externally, a profile is referenced by means of a
-<a href="#terms-profile-designator">profile designator</a>. When defined internally (inline), a profile is referenced either implicitly
-or by means of <a href="#terms-profile-fragment-identifier">profile fragment identifier</a>.</p><table border="1" class="ednote" summary="Editorial note: Profile Fragment Identifiers."><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Profile Fragment Identifiers.</b></td><td align="right" valign="top">2014-05-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Update following to account for use of profile fragment identifier as a profile designator.</td></tr></table><p>A profile designator must adhere to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17. If the profile designator is expressed as a relative URI,
-then it must be absolutized by using the TT Profile Namespace value as
-the base URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, if a profile designator is expressed as
-<code>ttml2-presentation</code>, then the absolutized profile designator
-would be
-<code>http://www.w3.org/ns/ttml/profile/ttml2-presentation</code>.</p></div><p>All profile designators which have the TT Profile Namespace as a prefix but are otherwise not listed in
-<a href="#profile-vocab-table"><b>Table 5-2 – Profiles</b></a> are reserved for future standardization, and must not appear in a conformant
-<a href="#terms-document-instance">document instance</a>. Nothwithstanding this constraint, a profile designator is not restricted to the set of designators enumerated
-in <a href="#profile-vocab-table"><b>Table 5-2 – Profiles</b></a>, but may be any URI that feasibly dereferences a TTML <a href="#terms-profile-definition-document">profile definition document</a>
-provided it does not use the TT Profile Namespace as a prefix.</p><div class="div4">
-<h5><a id="vocabulary-profile-standard-designators"></a>5.2.3.1 Standard Designators</h5><p>The Timed Text Markup Language (TTML) employs a number of
-standard, predefined profiles of its
-vocabulary and associated semantics.</p><p>The following table specifies this set of
-profiles, indicating
-a normative name
-and designator for each
-predefined profile,
-and where each of these profiles is formally elaborated in
-<a href="#standard-profiles"><b>G Standard Profiles</b></a>, in <a href="#ttml1">[TTML1]</a>,
-or in another TTWG specification.</p><a id="profile-vocab-table"></a><table class="common"><caption>Table 5-2 – Profiles</caption><col width="25%" span="1"><col span="1"><tbody><tr><th>Name</th><th>Designator</th></tr><tr><td>DFXP Full</td><td><code>http://www.w3.org/ns/ttml/profile/dfxp-full</code></td></tr><tr><td>DFXP Presentation</td><td><code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code></td></tr><tr><td>DFXP Transformation</td><td><code>http://www.w3.org/ns/ttml/profile/dfxp-transformation</code></td></tr><tr><td>SDP US</td><td><code>http://www.w3.org/ns/ttml/profile/sdp-us</code></td></tr><tr><td>TTML2 Full</td><td><code>http://www.w3.org/ns/ttml/profile/ttml2-full</code></td></tr><tr><td>TTML2 Presentation</td><td><code>http://www.w3.org/ns/ttml/profile/ttml2-presentation</code></td></tr><tr><td>TTML2 Transformation</td><td><code>http://www.w3.org/ns/ttml/profile/ttml2-transformation</code></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>For definitions of the DFXP profiles, see <a href="#ttml1">[TTML1]</a>. For definition of the SDP US profile, see <a href="#sdpus">[SDP US]</a>.</p></div></div></div><div class="div3">
-<h4><a id="semantics-profile-semantics"></a>5.2.4 Profile Semantics</h4><div class="div4">
-<h5><a id="semantics-profile-state"></a>5.2.4.1 Profile State Object Concepts</h5><p>This section defines a number of conceptual state objects used by subsequently defined algorithms (procedures and functions). It is not required that an
-implementation create such objects in the form specified here, but may use any convenient, internal representation that represents equivalent information.</p><dl><dt class="label"><a id="semantics-profile-state-profile-specification"></a>[profile specification]</dt><dd><p>a <a href="#semantics-profile-state-profile-specification"><span class="strong">profile specification</span></a>
-represents the following internal state information that corresponds with
-a <a href="#profile-vocabulary-feature"><code>ttp:feature</code></a> or <a href="#profile-vocabulary-extension"><code>ttp:extension</code></a>
-element</p><dl><dt class="label"><a id="semantics-profile-state-profile-specification-designator"></a>designator</dt><dd><p>an absolute xsd:anyURI denoting a feature or extension designator depending upon the <em><code>type</code></em></p></dd><dt class="label"><a id="semantics-profile-state-profile-specification-type"></a>type</dt><dd><p><code>feature|extension</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-specification-value"></a>value</dt><dd><p><code>optional|required|prohibited</code></p></dd></dl></dd><dt class="label"><a id="semantics-profile-state-combined-profile-specification-set"></a>[combined profile specification set]</dt><dd><p>a <a href="#semantics-profile-state-combined-profile-specification-set"><span class="strong">combined profile specification set</span></a>
-represents the following internal state information
-that corresponds with a set of <a href="#semantics-profile-state-profile-specification"><span class="strong">profile specifications</span></a>,
-additionally recording the constituent
-profiles from which these specifications were obtained (or derived)</p><dl><dt class="label"><a id="semantics-profile-state-combined-profile-specification-set-constituents"></a>constituents</dt><dd><p>ordered list of absolute profile designators, where each designator denotes a constituent profile, i.e.,
-a profile from which this combined profile specification set is composed</p></dd><dt class="label"><a id="semantics-profile-state-combined-profile-specification-set-specifications"></a>specifications</dt><dd><p>ordered list of <a href="#semantics-profile-state-profile-specification"><span class="strong">profile specifications</span></a></p></dd></dl></dd><dt class="label"><a id="semantics-profile-state-empty-profile-specification-set"></a>[empty profile specification set]</dt><dd><p>a <a href="#semantics-profile-state-combined-profile-specification-set"><span class="strong">combined profile specification set</span></a> which 
-<a href="#semantics-profile-state-combined-profile-specification-set-constituents"><span class="strong">constituents</span></a> and
-<a href="#semantics-profile-state-combined-profile-specification-set-specifications"><span class="strong">specifications</span></a> fields are empty sets</p></dd><dt class="label"><a id="semantics-profile-state-profile"></a>[profile]</dt><dd><p>a <a href="#semantics-profile-state-profile"><span class="strong">profile</span></a> represents the following internal state information
-that corresponds with a <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element, whether specified explicitly or implied</p><dl><dt class="label"><a id="semantics-profile-state-profile-designator"></a>designator</dt><dd><p>an absolute profile designator that is associated with (and uniquely labels) this profile</p></dd><dt class="label"><a id="semantics-profile-state-profile-type"></a>type</dt><dd><p><code>content|processor</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-combine"></a>combine</dt><dd><p><code>leastRestrictive|mostRestrictive|replace</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-use"></a>use</dt><dd><p>either <code>null</code> or an absolute profile designator denoting a profile that serves as the baseline profile for this profile</p></dd><dt class="label"><a id="semantics-profile-state-profile-constituents"></a>constituents</dt><dd><p>if profile is a <a href="#terms-nesting-profile">nesting profile</a>, then an ordered list of absolute profile designators, where each designator denotes a
-constituent <a href="#terms-nested-profile">nested profile</a>; otherwise, <code>null</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-specifications"></a>specifications</dt><dd><p>if profile is a <a href="#terms-non-nesting-profile">non-nesting profile</a>, then an ordered list of
-<a href="#semantics-profile-state-profile-specification"><span class="strong">profile specifications</span></a>; otherwise, <code>null</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-combined-specification-set"></a>combined specification set</dt><dd><p>a <a href="#semantics-profile-state-combined-profile-specification-set"><span class="strong">combined profile specification set</span></a> that
-represents the results of combining the specifications specified or referenced by this profile</p></dd></dl></dd></dl></div><div class="div4">
-<h5><a id="semantics-content-profile-processing"></a>5.2.4.2 Content Profile Semantics</h5><table border="1" class="ednote" summary="Editorial note: Validation Processing"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Validation Processing</b></td><td align="right" valign="top">2014-05-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add validation processing procedures.</td></tr></table><dl><dt class="label"><a id="semantics-procedure-construct-effective-content-profile"></a>[construct effective content profile]</dt><dd><p>Every TTML <a href="#terms-document-instance">document instance</a> is associated with an
-<a href="#terms-effective-content-profile">effective content profile</a> which may be used by
-a <a href="#terms-content-processor">content processor</a> to perform any (or all) of the following:</p><ol class="enumar"><li><p>infer an effective processor profile;</p></li><li><p>perform validation processing on the <a href="#terms-document-instance">document instance</a>;</p></li><li><p>constrain transformation processing on the <a href="#terms-document-instance">document instance</a>
-in order to maintain content profile invariants.</p></li></ol><p>The <a href="#terms-effective-content-profile">effective content profile</a> is determined according to the
-<a href="#semantics-procedure-construct-effective-content-profile"><span class="strong">construct effective content profile</span></a> procedure
-defined as follows:</p><ol class="enumar"><li><p>if a <code>ttp:contentProfiles</code> attribute is specified on the root <code>tt</code> element, then</p><ol class="enumla"><li><p>if the <code>ttp:contentProfiles</code> attribute is specified using the <code>all(...)</code> function syntax or
-using no function syntax, i.e., as only a list of designators, then the
-<a href="#terms-effective-content-profile">effective content profile</a> is the combined profile specification set
-produced by combining the combined profile specification sets of the designated profiles, where the <code>mostRestrictive</code>
-content profile combination method applies;</p></li><li><p>otherwise, if the <code>ttp:contentProfiles</code> attribute is specified using the <code>any(...)</code> function syntax, then the
-<a href="#terms-effective-content-profile">effective content profile</a> is the combined profile specification set
-produced by combining the combined profile specification sets of the designated profiles, where the <code>leastRestrictive</code>
-content profile combination method applies;</p></li></ol></li><li><p>otherwise, if one or more <a href="#terms-top-level-profile">top-level</a> <a href="#terms-content-profile">content profiles</a>
-are defined, then the
-<a href="#terms-effective-content-profile">effective content profile</a> is the combined profile specification set
-produced by combining the combined profile specification sets of all such
-<a href="#terms-top-level-profile">top-level</a> <a href="#terms-content-profile">content profiles</a>, where the
-content profile combination method specified by (or the default value of) the <code>ttp:contentProfileCombination</code>
-attribute on the root <code>tt</code> element applies;
-</p></li><li><p>otherwise, the <a href="#terms-effective-content-profile">effective content profile</a> is <code>null</code>;</p></li></ol></dd></dl></div><div class="div4">
-<h5><a id="semantics-processor-profile-processing"></a>5.2.4.3 Processor Profile Semantics</h5><dl><dt class="label"><a id="semantics-procedure-abort-if-unsupported-processor-profile"></a>[abort if unsupported processor profile]</dt><dd><ol class="enumar"><li><p>set <em>EPP</em> to the <a href="#terms-effective-processor-profile">effective processor profile</a> obtained by performing the
-<a href="#semantics-procedure-construct-effective-processor-profile"><span class="strong">construct effective processor profile</span></a> procedure;</p></li><li><p>for each profile specification <em>S</em> in the combined profile specification set of <em>EPP</em>, perform the following steps:</p><ol class="enumla"><li><p>if the <span class="strong">value</span> field of <em>S</em> is <code>required</code>, and the <a href="#terms-content-processor">content processor</a>
-does not support <em>S</em>, then abort processing of the <a href="#terms-document-instance">document instance</a> unless overridden
-by the end-user or some implementation specific parameter traceable to an end-user or to a user or system configuration setting;</p></li></ol></li></ol></dd><dt class="label"><a id="semantics-procedure-construct-effective-processor-profile"></a>[construct effective processor profile]</dt><dd><p>Every TTML <a href="#terms-document-instance">document instance</a> is associated with an
-<a href="#terms-effective-processor-profile">effective processor profile</a> which is used by
-a <a href="#terms-content-processor">content processor</a> to determine whether it meets the
-minimum processing requirements signaled by the content author, and if not, then must abort further
-processing unless overridden by the end-user or an implementation specific parameter traceable to
-an end-user or to a user or system configuration setting.
-The <a href="#terms-effective-processor-profile">effective processor profile</a> is determined according to the
-<a href="#semantics-procedure-construct-effective-processor-profile"><span class="strong">construct effective processor profile</span></a> procedure
-defined as follows:</p><ol class="enumar"><li><p>if a <code>ttp:processorProfiles</code> attribute is specified on the root <code>tt</code> element, then</p><ol class="enumla"><li><p>if the <code>ttp:processorProfiles</code> attribute is specified using the <code>all(...)</code> function syntax or
-using no function syntax, i.e., as only a list of designators, then the
-<a href="#terms-effective-processor-profile">effective processor profile</a> is the combined profile specification set
-produced by combining the combined profile specification sets of the designated profiles, where the <code>mostRestrictive</code>
-processor profile combination method applies;</p></li><li><p>otherwise, if the <code>ttp:processorProfiles</code> attribute is specified using the <code>any(...)</code> function syntax,
-then, for each designated profile, the 
-<a href="#terms-effective-processor-profile">effective processor profile</a> is the combined profile specification set
-of the first profile in the list of designated profiles that is supported by the
-<a href="#terms-content-processor">content processor</a>;</p></li></ol></li><li><p>otherwise, if one or more <a href="#terms-top-level-profile">top-level</a> <a href="#terms-processor-profile">processor profiles</a>
-are defined, then the
-<a href="#terms-effective-processor-profile">effective processor profile</a> is the combined profile specification set
-produced by combining the combined profile specification sets of all such
-<a href="#terms-top-level-profile">top-level</a> <a href="#terms-processor-profile">processor profiles</a>, where the
-processor profile combination method specified by (or the default value of) the <code>ttp:processorProfileCombination</code>
-attribute on the root <code>tt</code> element applies;
-</p></li><li><p>otherwise, if a <code>ttp:profile</code> attribute is specified on the root <code>tt</code> element, then the
-<a href="#terms-effective-processor-profile">effective processor profile</a> is the combined profile specification set
-of the profile designated by this attribute;
-</p></li><li><p>otherwise, the <a href="#terms-effective-processor-profile">effective processor profile</a> is the
-result of performing the <a href="#semantics-procedure-construct-inferred-processor-profile"><span class="strong">construct inferred processor profile</span></a>
-procedure;</p></li></ol></dd><dt class="label"><a id="semantics-procedure-construct-inferred-processor-profile"></a>[construct inferred processor profile]</dt><dd><ol class="enumar"><li><p>set <em>ECP</em> to the <a href="#terms-effective-content-profile">effective content profile</a>;</p></li><li><p>if <em>ECP</em> is not <code>null</code>, then perform the following steps:</p><ol class="enumla"><li><p>if the computed value of the <code>ttp:inferProcessorProfileSource</code> parameter is <code>combine</code>, then
-the <a href="#terms-inferred-processor-profile">inferred processor profile</a> is the result of applying the
-<a href="#semantics-procedure-infer-processor-profile"><span class="strong">infer processor profile</span></a> function
-to the combined profile specification set of <em>ECP</em>;</p></li><li><p>otherwise, if the computed value of the <code>ttp:inferProcessorProfileSource</code> parameter is <code>first</code>, then
-the <a href="#terms-inferred-processor-profile">inferred processor profile</a> is the first inferred processor profile, <em>IPP</em>, produced by applying the
-<a href="#semantics-procedure-infer-processor-profile"><span class="strong">infer processor profile</span></a> function
-to the combined profile specification set of each constituent of <em>ECP</em> such that
-<em>IPP</em> is supported by the <a href="#terms-content-processor">content processor</a>;</p></li></ol></li><li><p>otherwise, the <a href="#terms-inferred-processor-profile">inferred processor profile</a> is the
-result of performing the <a href="#semantics-procedure-construct-default-processor-profile"><span class="strong">construct default processor profile</span></a>
-procedure;</p></li></ol></dd><dt class="label"><a id="semantics-procedure-infer-processor-profile"></a>[infer processor profile](content profile <em>CP</em>)</dt><dd><ol class="enumar"><li><p>initialize inferred processor profile <em>IPP</em> to the empty combined profile specification set;</p></li><li><p>for each profile specification, <em>S</em>, in the combined profile specification set of content profile <em>CP</em>:</p><ol class="enumla"><li><p>map content profile specification <em>S</em> to processor profile specification <em>S'&nbsp;</em> according to the computed
-value of the <code>ttp:inferPresentationProfileMethod</code> parameter and <a href="#infer-processor-profile-method-table"><b>Table 6-2 – Infer Processor Profile Method</b></a>;</p></li><li><p>add <em>S'&nbsp;</em> to the combined profile specification set of <em>IPP</em>;</p></li></ol></li><li><p>return <em>IPP</em> as the inferred processor profile;</p></li></ol></dd><dt class="label"><a id="semantics-procedure-construct-default-processor-profile"></a>[construct default processor profile]</dt><dd><ol class="enumar"><li><p>if the <a href="#terms-document-interchange-context">document interchange context</a> is associated with a
-<a href="#terms-processor-profile">processor profile</a> or with a <a href="#terms-content-profile">content profile</a>
-from which a <a href="#terms-processor-profile">processor profile</a> can be inferred, then the
-<a href="#terms-default-processor-profile">default processor profile</a> is that <a href="#terms-processor-profile">processor profile</a>;</p></li><li><p>otherwise, if the <a href="#terms-content-processor">content processor</a> is primarily characterized as a
-<a href="#terms-presentation-processor">presentation processor</a>, then:</p><ol class="enumla"><li><p>if the <a href="#parameter-attribute-version"><code>ttp:version</code></a> attribute is not specified on the root <code>tt</code> element or
-if the computed value of its parameter property is <code>1</code> (one), then the <a href="#terms-default-processor-profile">default processor profile</a> is
-the <a href="#semantics-profile-state-profile">profile</a> constructed by interning the DFXP Presentation profile
-(<code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code>);</p></li><li><p>otherwise,
-if the computed value of the <a href="#parameter-attribute-version"><code>ttp:version</code></a> parameter property is <code>2</code> (two),
-the <a href="#terms-default-processor-profile">default processor profile</a> is
-the <a href="#semantics-profile-state-profile">profile</a> constructed by interning the TTML2 Presentation profile
-(<code>http://www.w3.org/ns/ttml/profile/ttml2-presentation</code>);</p></li><li><p>otherwise,
-the <a href="#terms-default-processor-profile">default processor profile</a> is
-the <a href="#semantics-profile-state-profile">profile</a> constructed by interning a TTML presentation profile
-associated with the computed value of <a href="#parameter-attribute-version"><code>ttp:version</code></a>,
-if one is known, or, if not known, then the most recently defined presentation profile;</p></li></ol></li><li><p>otherwise, if the <a href="#terms-content-processor">content processor</a> is primarily characterized as a
-<a href="#terms-transformation-processor">transformation processor</a>, then:</p><ol class="enumla"><li><p>if the <a href="#parameter-attribute-version"><code>ttp:version</code></a> attribute is not specified on the root <code>tt</code> element or
-if the computed value of its parameter property is <code>1</code> (one), then the <a href="#terms-default-processor-profile">default processor profile</a> is
-the <a href="#semantics-profile-state-profile">profile</a> constructed by interning the DFXP Transformation profile
-(<code>http://www.w3.org/ns/ttml/profile/dfxp-transformation</code>);</p></li><li><p>otherwise,
-if the computed value of the <a href="#parameter-attribute-version"><code>ttp:version</code></a> parameter property is <code>2</code> (two),
-the <a href="#terms-default-processor-profile">default processor profile</a> is
-the <a href="#semantics-profile-state-profile">profile</a> constructed by interning the TTML2 Transformation profile
-(<code>http://www.w3.org/ns/ttml/profile/ttml2-transformation</code>);</p></li><li><p>otherwise,
-the <a href="#terms-default-processor-profile">default processor profile</a> is
-the <a href="#semantics-profile-state-profile">profile</a> constructed by interning a TTML transformation profile
-associated with the computed value of <a href="#parameter-attribute-version"><code>ttp:version</code></a>,
-if one is known, or, if not known, then the most recently defined TTML transformation profile;</p></li></ol></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>A <a href="#terms-content-processor">content processor</a> intended to be used with
-one or more distinct versions of TTML greater than version 2 (TTML2) may choose a
-<a href="#terms-default-processor-profile">default processor profile</a> based upon
-a future version of a TTML presentation or transformation profile.</p></div></dd></dl></div></div></div><div class="div2">
-<h3><a id="vocabulary-overview"></a>5.3 Catalog</h3><p>The vocabulary of the Timed Text Markup Language (TTML) is
-defined in the following major catalogs (divisions of vocabulary):</p><ul><li><p><a href="#core-vocabulary-overview"><b>5.3.1 Core Catalog</b></a></p></li><li><p><a href="#extension-vocabulary-overview"><b>5.3.2 Extension Catalog</b></a></p></li></ul><p>The core catalog defines the baseline, core vocabulary of TTML,
-and, in particular, the vocabulary of TTML Content. The extension catalog
-serves as a placeholder for extensions to the core vocabulary defined
-by TTML.</p><div class="div3">
-<h4><a id="core-vocabulary-overview"></a>5.3.1 Core Catalog</h4><p>The core vocabulary catalog is intended to satisfy the needs of
-TTML while providing a baseline vocabulary for future profiles. This vocabulary
-is divided into distinct categories, specified in detail
-in the following sections:</p><ul><li><p><a href="#profile"><b>6 Profile</b></a></p></li><li><p><a href="#parameter"><b>7 Parameter</b></a></p></li><li><p><a href="#content"><b>8 Content</b></a></p></li><li><p><a href="#embedded-content"><b>9 Embedded Content</b></a></p></li><li><p><a href="#styling"><b>10 Styling</b></a></p></li><li><p><a href="#layout"><b>11 Layout</b></a></p></li><li><p><a href="#timing"><b>12 Timing</b></a></p></li><li><p><a href="#animation"><b>13 Animation</b></a></p></li><li><p><a href="#metadata"><b>14 Metadata</b></a></p></li></ul><p>The core element vocabulary specified for use with a <a href="#terms-document-instance">document instance</a> is enumerated in
-<a href="#element-vocab-table"><b>Table 5-3 – Element Vocabulary</b></a>.</p><a id="element-vocab-table"></a><table class="common"><caption>Table 5-3 – Element Vocabulary</caption><col width="25%" span="1"><col span="1"><tbody><tr><th>Module</th><th>Elements</th></tr><tr id="element-vocab-type-animation"><td>
-Animation
-</td><td>
-<a href="#animation-vocabulary-animate">animate</a>,
-<a href="#animation-vocabulary-animation">animation</a>,
-<a href="#animation-vocabulary-set">set</a>
-</td></tr><tr id="element-vocab-type-audio"><td>
-Audio
-</td><td>
-<a href="#data-vocabulary-audio">audio</a>
-</td></tr><tr id="element-vocab-type-content"><td>
-Content
-</td><td>
-<a href="#document-structure-vocabulary-body">body</a>,
-<a href="#content-vocabulary-br">br</a>,
-<a href="#content-vocabulary-div">div</a>,
-<a href="#content-vocabulary-p">p</a>,
-<a href="#content-vocabulary-span">span</a>
-</td></tr><tr id="element-vocab-type-data"><td>
-Data
-</td><td>
-<a href="#data-vocabulary-data">chunk</a>,
-<a href="#data-vocabulary-data">data</a>,
-<a href="#data-vocabulary-resources">resources</a>,
-<a href="#data-vocabulary-source">source</a>
-</td></tr><tr id="element-vocab-type-document"><td>
-Document
-</td><td>
-<a href="#document-structure-vocabulary-tt">tt</a>
-</td></tr><tr id="element-vocab-type-font"><td>
-Font
-</td><td>
-<a href="#data-vocabulary-font">font</a>
-</td></tr><tr id="element-vocab-type-head"><td>
-Head
-</td><td>
-<a href="#document-structure-vocabulary-head">head</a>
-</td></tr><tr id="element-vocab-type-image"><td>
-Image
-</td><td>
-<a href="#data-vocabulary-image">image</a>
-</td></tr><tr id="element-vocab-type-layout"><td>
-Layout
-</td><td>
-<a href="#layout-vocabulary-layout">layout</a>,
-<a href="#layout-vocabulary-region">region</a>
-</td></tr><tr id="element-vocab-type-metadata"><td>
-Metadata
-</td><td>
-<a href="#metadata-vocabulary-metadata">metadata</a>
-</td></tr><tr id="element-vocab-type-metadata-items"><td>
-Metadata Items
-</td><td>
-<a href="#metadata-vocabulary-actor">ttm:actor</a>,
-<a href="#metadata-vocabulary-agent">ttm:agent</a>,
-<a href="#metadata-vocabulary-copyright">ttm:copyright</a>,
-<a href="#metadata-vocabulary-desc">ttm:desc</a>,
-<a href="#metadata-vocabulary-item">ttm:item</a>,
-<a href="#metadata-vocabulary-name">ttm:name</a>,
-<a href="#metadata-vocabulary-title">ttm:title</a>
-</td></tr><tr id="element-vocab-type-profile"><td>Profile</td><td>
-<a href="#profile-vocabulary-features">ttp:features</a>,
-<a href="#profile-vocabulary-feature">ttp:feature</a>,
-<a href="#profile-vocabulary-extensions">ttp:extensions</a>,
-<a href="#profile-vocabulary-extension">ttp:extension</a>,
-<a href="#profile-vocabulary-profile">ttp:profile</a>
-</td></tr><tr id="element-vocab-type-styling"><td>
-Styling
-</td><td>
-<a href="#styling-vocabulary-initial">initial</a>,
-<a href="#styling-vocabulary-styling">styling</a>,
-<a href="#styling-vocabulary-style">style</a>
-</td></tr></tbody></table><p></p><p>Element vocabulary groups that are used in defining content models
-for TTML element types are enumerated in <a href="#element-vocab-group-table"><b>Table 5-4 – Element Vocabulary Groups</b></a>.</p><a id="element-vocab-group-table"></a><table class="common"><caption>Table 5-4 – Element Vocabulary Groups</caption><col width="25%" span="1"><col span="1"><tbody><tr><th>Group</th><th>Elements</th></tr><tr id="element-vocab-group-animation"><td>
-Animation.class
-</td><td>
-<a href="#animation-vocabulary-animate">animate</a> |
-<a href="#animation-vocabulary-set">set</a>
-</td></tr><tr id="element-vocab-group-block"><td>
-Block.class
-</td><td>
-<a href="#content-vocabulary-div">div</a> |
-<a href="#content-vocabulary-p">p</a>
-</td></tr><tr id="element-vocab-group-data"><td>
-Data.class
-</td><td>
-<a href="#data-vocabulary-data">data</a>
-</td></tr><tr id="element-vocab-group-embedded"><td>
-Embedded.class
-</td><td>
-<a href="#data-vocabulary-audio">audio</a>,
-<a href="#data-vocabulary-image">image</a>
-</td></tr><tr id="element-vocab-group-font"><td>
-Font.class
-</td><td>
-<a href="#data-vocabulary-font">font</a>
-</td></tr><tr id="element-vocab-group-inline"><td>
-Inline.class
-</td><td>
-<a href="#content-vocabulary-span">span</a> |
-<a href="#content-vocabulary-span">br</a> |
-<code>#PCDATA</code>
-</td></tr><tr><td>
-Layout.class
-</td><td id="element-vocab-group-layout">
-<a href="#layout-vocabulary-region">region</a>
-</td></tr><tr id="element-vocab-group-metadata"><td>
-Metadata.class
-</td><td>
-<a href="#metadata-vocabulary-metadata">metadata</a> |
-<a href="#metadata-vocabulary-copyright">ttm:agent</a> |
-<a href="#metadata-vocabulary-copyright">ttm:copyright</a> |
-<a href="#metadata-vocabulary-desc">ttm:desc</a> |
-<a href="#metadata-vocabulary-desc">ttm:item</a> |
-<a href="#metadata-vocabulary-title">ttm:title</a>
-</td></tr><tr id="element-vocab-group-profile"><td>Profile.class</td><td><a href="#profile-vocabulary-profile">ttp:profile</a></td></tr></tbody></table><p></p><p>The attribute vocabulary specified for use with the core vocabulary
-catalog is enumerated in
-<a href="#attribute-vocab-table"><b>Table 5-5 – Attribute Vocabulary</b></a>.</p><a id="attribute-vocab-table"></a><table class="common"><caption>Table 5-5 – Attribute Vocabulary</caption><col width="25%" span="1"><col span="1"><tbody><tr><th>Module</th><th>Attributes</th></tr><tr id="attribute-vocab-group-animation-binding"><td>
-Animation Binding Attribute
-</td><td>
-<a href="#animation-attribute-animate">animate</a>
-</td></tr><tr id="attribute-vocab-group-core"><td>
-Core Attributes
-</td><td>
-<a href="#content-attribute-xml-id">xml:id</a>,
-<a href="#content-attribute-xml-lang">xml:lang</a>,
-<a href="#content-attribute-xml-space">xml:space</a>
-</td></tr><tr id="attribute-vocab-group-data"><td>
-Data Attributes
-</td><td>
-<a href="#embedded-content-attribute-encoding">encoding</a>,
-<a href="#embedded-content-attribute-format">format</a>,
-<a href="#embedded-content-attribute-src">src</a>,
-<a href="#embedded-content-attribute-type">type</a>
-</td></tr><tr id="attribute-vocab-group-layout-binding"><td>
-Layout Binding Attribute
-</td><td>
-<a href="#layout-attribute-region">region</a>
-</td></tr><tr id="attribute-vocab-group-metadata"><td>
-Metadata Attributes
-</td><td>
-<a href="#metadata-attribute-agent">ttm:agent</a>,
-<a href="#metadata-attribute-role">ttm:role</a>
-</td></tr><tr id="attribute-vocab-group-parameters"><td>
-Parameter Attributes
-</td><td>
-<a href="#parameter-attribute-cellResolution">ttp:cellResolution</a>,
-<a href="#parameter-attribute-clockMode">ttp:clockMode</a>,
-<a href="#parameter-attribute-dropMode">ttp:dropMode</a>,
-<a href="#parameter-attribute-frameRate">ttp:frameRate</a>,
-<a href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultipler</a>,
-<a href="#parameter-attribute-markerMode">ttp:markerMode</a>,
-<a href="#parameter-attribute-mediaDuration">ttp:mediaDuration</a>,
-<a href="#parameter-attribute-mediaOffset">ttp:mediaOffset</a>,
-<a href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</a>,
-<a href="#parameter-attribute-storageAspectRatio">ttp:storageAspectRatio</a>,
-<a href="#parameter-attribute-subFrameRate">ttp:subFrameRate</a>,
-<a href="#parameter-attribute-tickRate">ttp:tickRate</a>,
-<a href="#parameter-attribute-timeBase">ttp:timeBase</a>,
-</td></tr><tr id="attribute-vocab-group-profile"><td>
-Profile Attributes
-</td><td>
-<a href="#profile-attribute-contentProfiles">ttp:contentProfiles</a>,
-<a href="#profile-attribute-contentProfileCombination">ttp:contentProfileCombination</a>,
-<a href="#profile-attribute-inferProcessorProfileMethod">ttp:inferProcessorProfileMethod</a>,
-<a href="#profile-attribute-inferProcessorProfileSource">ttp:inferProcessorProfileSource</a>,
-<a href="#profile-attribute-permitFeatureNarrowing">ttp:permitFeatureNarrowing</a>,
-<a href="#profile-attribute-permitFeatureWidening">ttp:permitFeatureWidening</a>,
-<a href="#profile-attribute-profile">ttp:profile</a>,
-<a href="#profile-attribute-processorProfiles">ttp:processorProfiles</a>,
-<a href="#profile-attribute-processorProfileCombination">ttp:processorProfileCombination</a>,
-<a href="#profile-attribute-validation">ttp:validation</a>,
-<a href="#profile-attribute-validationAction">ttp:validationAction</a>,
-<a href="#profile-attribute-version">ttp:version</a>
-</td></tr><tr id="attribute-vocab-group-style-binding"><td>
-Style Binding Attribute
-</td><td>
-<a href="#style-attribute-style">style</a>
-</td></tr><tr id="attribute-vocab-group-style"><td>
-Styling Attributes
-</td><td>
-<a href="#style-attribute-backgroundColor">tts:backgroundColor</a>,
-<a href="#style-attribute-backgroundImage">tts:backgroundImage</a>,
-<a href="#style-attribute-backgroundPosition">tts:backgroundPosition</a>,
-<a href="#style-attribute-backgroundRepeat">tts:backgroundRepeat</a>,
-<a href="#style-attribute-border">tts:border</a>,
-<a href="#style-attribute-color">tts:color</a>,
-<a href="#style-attribute-direction">tts:direction</a>,
-<a href="#style-attribute-display">tts:display</a>,
-<a href="#style-attribute-displayAlign">tts:displayAlign</a>,
-<a href="#style-attribute-extent">tts:extent</a>,
-<a href="#style-attribute-fontFamily">tts:fontFamily</a>,
-<a href="#style-attribute-fontKerning">tts:fontKerning</a>,
-<a href="#style-attribute-fontSelectionStrategy">tts:fontSelectionStrategy</a>,
-<a href="#style-attribute-fontShear">tts:fontShear</a>,
-<a href="#style-attribute-fontSize">tts:fontSize</a>,
-<a href="#style-attribute-fontStyle">tts:fontStyle</a>,
-<a href="#style-attribute-fontVariantPosition">tts:fontVariantPosition</a>,
-<a href="#style-attribute-fontWeight">tts:fontWeight</a>,
-<a href="#style-attribute-height">tts:height</a>,
-<a href="#style-attribute-letterSpacing">tts:letterSpacing</a>,
-<a href="#style-attribute-lineHeight">tts:lineHeight</a>,
-<a href="#style-attribute-opacity">tts:opacity</a>,
-<a href="#style-attribute-origin">tts:origin</a>,
-<a href="#style-attribute-overflow">tts:overflow</a>,
-<a href="#style-attribute-padding">tts:padding</a>,
-<a href="#style-attribute-position">tts:position</a>,
-<a href="#style-attribute-ruby">tts:ruby</a>,
-<a href="#style-attribute-rubyAlign">tts:rubyAlign</a>,
-<a href="#style-attribute-rubyOffset">tts:rubyOffset</a>,
-<a href="#style-attribute-rubyPosition">tts:rubyPosition</a>,
-<a href="#style-attribute-showBackground">tts:showBackground</a>,
-<a href="#style-attribute-textAlign">tts:textAlign</a>,
-<a href="#style-attribute-textCombine">tts:textCombine</a>,
-<a href="#style-attribute-textDecoration">tts:textDecoration</a>,
-<a href="#style-attribute-textEmphasis">tts:textEmphasis</a>,
-<a href="#style-attribute-textOrientation">tts:textOrientation</a>,
-<a href="#style-attribute-textOutline">tts:textOutline</a>,
-<a href="#style-attribute-textShadow">tts:textShadow</a>,
-<a href="#style-attribute-unicodeBidi">tts:unicodeBidi</a>,
-<a href="#style-attribute-visibility">tts:visibility</a>,
-<a href="#style-attribute-width">tts:width</a>,
-<a href="#style-attribute-wrapOption">tts:wrapOption</a>,
-<a href="#style-attribute-writingMode">tts:writingMode</a>,
-<a href="#style-attribute-zIndex">tts:zIndex</a>
-</td></tr><tr id="attribute-vocab-group-timing"><td>
-Timing Attributes
-</td><td>
-<a href="#timing-attribute-begin">begin</a>,
-<a href="#timing-attribute-dur">dur</a>,
-<a href="#timing-attribute-end">end</a>,
-<a href="#timing-attribute-timeContainer">timeContainer</a>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>Only those attributes defined as either (1) global, i.e., namespace qualified, or
-(2) shared element-specific, i.e., not namespace qualified but shared across multiple
-element types, are listed in <a href="#attribute-vocab-table"><b>Table 5-5 – Attribute Vocabulary</b></a> above.
-</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>All vocabulary defined by TTML consistently makes use of
-the so-called <em>lowerCamelCase</em> naming convention. In some cases, this results in the
-change of a name when the name was based upon another specification
-that used a different naming convention.</p></div></div><div class="div3">
-<h4><a id="extension-vocabulary-overview"></a>5.3.2 Extension Catalog</h4><p>The extension vocabulary catalog is intended for use by future
-profiles of TTML, and is not further defined
-by this version of this specification.</p><p>In addition to standardized extension vocabulary, a conforming 
-<a href="#terms-document-instance">document instance</a> may contain arbitrary namespace qualified
-elements that reside in any namespace other than those namespaces
-defined for use with this specification. Furthermore, a conforming 
-<a href="#terms-document-instance">document instance</a> may contain arbitrary namespace qualified
-attributes on TTML defined vocabulary where such attributes reside in
-any namespace other than those defined for use with this
-specification.</p></div></div></div><div class="div1">
-<h2><a id="profile"></a>6 Profile</h2><p>This section specifies the <em>profile</em> matter of the
-core vocabulary catalog, where profile matter is to be understood as information that expresses requirements or optionality related to authoring or processing
-a <a href="#terms-timed-text-content-document">timed text content document</a>.</p><div class="div2">
-<h3><a id="profile-element-vocabulary"></a>6.1 Profile Element Vocabulary</h3><p>The following elements, all defined in the TT Parameter
-Namespace, specify parametric information that applies to a <a href="#terms-document-instance">document instance</a>
-or <a href="#terms-content-processor">content processor</a>:</p><ul><li><p><a href="#profile-vocabulary-profile"><b>6.1.1 ttp:profile</b></a></p></li><li><p><a href="#profile-vocabulary-features"><b>6.1.2 ttp:features</b></a></p></li><li><p><a href="#profile-vocabulary-feature"><b>6.1.3 ttp:feature</b></a></p></li><li><p><a href="#profile-vocabulary-extensions"><b>6.1.4 ttp:extensions</b></a></p></li><li><p><a href="#profile-vocabulary-extension"><b>6.1.5 ttp:extension</b></a></p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>The sub-sections of this section are ordered logically (from highest to lowest level construct).</p></div><div class="div3">
-<h4><a id="profile-vocabulary-profile"></a>6.1.1 ttp:profile</h4><p>The <code>ttp:profile</code> element is used to specify a
-<a href="#terms-processor-profile">processor profile</a> or a
-<a href="#terms-content-profile">content profile</a>.
-A <a href="#terms-processor-profile">processor profile</a> specifies a
-collection of required (mandatory) and optional (voluntary) features and extensions that must or
-may be supported by a <a href="#terms-content-processor">content processor</a> in order to process a
-<a href="#terms-document-instance">document instance</a> that makes (or may make) use of such features and
-extensions.
-A <a href="#terms-content-profile">content profile</a> specifies a
-collection of prohibited, required, and optional features and extensions that, respectively,
-must not, must, and may be present in a <a href="#terms-document-instance">document instance</a> that declares its
-adherence to the profile.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The difference between a <em>feature</em> and an
-<em>extension</em> is where it is defined and how it is labeled:
-if defined in this specification (or a future revision thereof) and
-labeled with a feature designation in <a href="#features"><b>E Features</b></a>, then
-it is considered to be a feature; if defined in another specification
-and labeled there with an extension designation, then it is considered
-to be an extension. In general, features are expected to be defined by
-the W3C standards process, while extensions are expected to be defined by
-third parties.</p></div><p>This specification defines two distinct contexts of use for the <code>ttp:profile</code> element:</p><ul><li><p>as a child of the <code>head</code> element or a <code>ttp:profile</code> element within a TTML <a href="#terms-document-instance">document instance</a>;</p></li><li><p>as the root element of a TTML <a href="#terms-profile-definition-document">profile definition document</a>
-instance;</p></li></ul><p>When a <code>ttp:profile</code> element appears within a TTML <a href="#terms-document-instance">document instance</a>,
-its purpose is to express authorial intentions about (1) which
-features and extensions must or may be supported by a recipient
-content processor in order to process that document or (2) which features and extensions must not, must, or may be
-included or otherwise used in that <a href="#terms-document-instance">document instance</a>.</p><p>When a <code>ttp:profile</code> element is used by a TTML <a href="#terms-profile-definition-document">profile definition document</a> instance,
-it serves to publish a machine
-readable specification of a specific TTML profile that may be referenced by TTML <a href="#terms-document-instance">document instances</a>.
-This specification defines a number of standard <em>Profile Definition Documents</em> in
-<a href="#standard-profiles"><b>G Standard Profiles</b></a>.</p><p>The <code>ttp:profile</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by either (1)
-zero or more <code>ttp:features</code> elements followed by
-zero or more <code>ttp:extensions</code> elements or (2)
-zero or more <code>ttp:profile</code> elements.
-When a <code>ttp:profile</code> element contains a child <code>ttp:profile</code> element, then the child is referred to as
-a <a href="#terms-nested-profile">nested profile</a> and the parent is referred to as a <a href="#terms-nesting-profile">nesting profile</a>;
-otherwise it is referred to as a <a href="#terms-non-nesting-profile">non-nesting profile</a>.</p><a id="elt-syntax-profile"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:profile</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttp:profile
-  combine = (leastRestrictive|mostRestrictive|replace) : replace
-  designator = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  type = (processor|content) : processor
-  use = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, ((<a href="#profile-vocabulary-features">ttp:features</a>*, <a href="#profile-vocabulary-extensions">ttp:extensions</a>*)|<a href="#profile-vocabulary-profile">ttp:profile</a>*)
-&lt;/ttp:profile&gt;
-</pre></div>
-</td></tr></tbody></table><p>The <code>type</code> attribute is used to determine whether a profile is a
-<a href="#terms-processor-profile">processor profile</a> or a
-<a href="#terms-content-profile">content profile</a>. If not specified,
-the profile is considered to be a <a href="#terms-processor-profile">processor profile</a>.
-If a <code>ttp:profile</code> element references a <a href="#terms-baseline-profile">baseline profile</a> or a
-<a href="#terms-nested-profile">nested profile</a>, then the type of the referenced profile must be the same as the type of the referencing profile. For
-example, a <code>ttp:profile</code> element that defines a <a href="#terms-processor-profile">processor profile</a> may only make reference to other
-<a href="#terms-processor-profile">processor profiles</a>, and may not reference a <a href="#terms-content-profile">content profile</a>.</p><p>The <code>combine</code> attribute is used to specify how
-feature or extension specifications are combined in the case that
-multiple specifications apply to the same feature or extension, respectively.</p><p>If the value of the <code>combine</code> attribute is <code>replace</code>, then a
-lexically subsequent feature or extension specification replaces a lexically prior
-specification, where specification elements are ordered as follows:</p><ol class="enumar"><li><p>specifications defined by a <a href="#terms-baseline-profile">baseline profile</a> referenced by a <code>use</code>
-attribute;</p></li><li><p>specifications defined by descendant <code>ttp:profile</code> elements in post-order
-traversal order;</p></li><li><p>specifications defined as descendant <code>ttp:feature</code> or <code>ttp:extension</code>
-elements in post-order traversal order.</p></li></ol><p>If the value is <code>leastRestrictive</code>, then the least restrictive specification value applies;
-if the value is <code>mostRestrictive</code>, then the most restrictive specification value
-applies. The order of restrictiveness is as follows (from least to most):
-<em>optional</em>, <em>required</em>, <em>prohibited</em>.</p><p>If the <code>combine</code> attribute is not specified, then replacement semantics apply.</p><p>If specified, the <code>designator</code> attribute must (1) adhere to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17 and (2) express an absolute URI that denotes a profile designator in
-accordance with <a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>. A <code>designator</code> attribute may
-be specified on a <code>ttp:profile</code> element that appears in a TTML
-<a href="#terms-document-instance">document instance</a>, and, if not specified,
-the defined profile is considered to be an undesignated profile.
-A <code>designator</code> attribute should
-be specified on a <code>ttp:profile</code> element that appears in a TTML
-<a href="#terms-profile-definition-document">profile definition document</a> instance,
-and, if not specified, the defining context (e.g., an external specification) must specify
-a designator in its accompanying definition text.</p><p>If specified, the <code>use</code> attribute must adhere to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17, and, furthermore, must denote a profile designator in
-accordance with <a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>. In this case,
-the profile designator must refer to (1) a standard, predefined
-<a href="#terms-profile-definition-document">profile definition document</a> as defined by <a href="#profile"><b>6 Profile</b></a>,
-or (2) a feasibly dereferenceable resource representing a valid <em>Profile Definition
-Document</em> instance. In either case, the referenced profile serves as the
-<a href="#terms-baseline-profile">baseline profile</a> of the specifying <code>ttp:profile</code> element.</p><p>If the <code>use</code> attribute is not specified, then the <a href="#terms-baseline-profile">baseline profile</a>
-of the <code>ttp:profile</code> element must be considered to be
-the empty (null) profile, i.e., a profile definition containing no
-feature or extension specifications.</p><p>The combined specification set <em>CSS</em> of features and extensions of a profile <em>P</em>
-is determined according to the following ordered rules, where merging a specification <em>S</em>
-into <em>CSS</em> entails applying a combination method in accordance with the specified
-(or default) value of the <code>combine</code> attribute, and where merging a combined specification set <em>CSS'&nbsp;</em> into
-<em>CSS</em> entails merging each ordered specification of <em>CSS'&nbsp;</em> into <em>CSS</em>:</p><ol class="enumar"><li><p>initialize <em>CSS</em> to the empty set;</p></li><li><p>if a <code>use</code> attribute is present, then merge
-the combined specification set of the referenced <a href="#terms-baseline-profile">baseline profile</a> into <em>CSS</em>;</p></li><li><p>for each <code>ttp:profile</code> child of the <em>P</em>,
-using a post-order traversal, merge the combined specification set of the child profile
-into <em>CSS</em>;</p></li><li><p>for each <code>ttp:feature</code> and <code>ttp:extension</code> child of the <code>ttp:profile</code> element,
-using a post-order traversal, merge the feature or extension specification
-into <em>CSS</em>.</p></li></ol><p>A conformant TTML processor is not required to be able to
-dereference a <a href="#terms-profile-definition-document">profile definition document</a> that is not one of the
-standard, predefined profiles defined by <a href="#standard-profiles"><b>G Standard Profiles</b></a>.  Furthermore,
-a conformant TTML processor may make use of a built-in, static
-form of each standard, predefined profile so as not to require
-dereferencing a network resource.</p><p>If a TTML processor is unable to dereference a non-standard
-<a href="#terms-profile-definition-document">profile definition document</a>, then it must not further process the
-document without the presence of an explicit override from an end-user
-or some implementation specific parameter traceable to an end-user or
-to a user or system configuration setting. If a TTML processor aborts
-processing of a <a href="#terms-document-instance">document instance</a> due to the inability to
-reference a non-standard <a href="#terms-profile-definition-document">profile definition document</a>, then some
-end-user notification should be given unless the end-user or system
-has disabled such a notification, or if the processor does not permit
-or entail the intervention of an end-user.</p><p>The <code>ttp:profile</code> element is illustrated by the following example.</p><a id="profile-vocabulary-profile-example-1"></a><table class="example"><caption>Example Fragment – ttp:profile</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttp:profile use="ttml2-presentation"&gt;
-  &lt;ttp:features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-    &lt;ttp:feature&gt;#text-outline&lt;/ttp:feature&gt;
-  &lt;/ttp:features&gt;
-&lt;/ttp:profile&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the TTML presentation profile is used as the
-baseline profile. This baseline profile is then supersetted (thus
-creating an additive derived profile) by requiring support for
-<code>#text-outline</code> feature.</p></div></div><div class="div3">
-<h4><a id="profile-vocabulary-features"></a>6.1.2 ttp:features</h4><p>The <code>ttp:features</code> element is a container element used to group
-infomation about feature support and usage requirements.</p><p>The <code>ttp:features</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by
-zero or more <code>ttp:feature</code> elements.</p><a id="elt-syntax-features"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:features</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttp:features
-  xml:base = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a> : <em>TT Feature Namespace</em>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#profile-vocabulary-feature">ttp:feature</a>*
-&lt;/ttp:features&gt;
-</pre></div>
-</td></tr></tbody></table><p>If specified, the <code>xml:base</code>
-attribute must (1) adhere to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17, (2) express an absolute URI that
-adheres to <a href="#xmlbase">[XML Base]</a> and,
-(3) express a feature namespace as defined by
-<a href="#feature-designations"><b>E.1 Feature Designations</b></a>. If not specified, the
-<code>xml:base</code> attribute's default
-value applies, which is the TT Feature Namespace.</p><p>The <code>xml:base</code> attribute is
-used to permit the abbreviation of feature designation URIs expressed
-by child <code>ttp:feature</code> elements.</p></div><div class="div3">
-<h4><a id="profile-vocabulary-feature"></a>6.1.3 ttp:feature</h4><p>The <code>ttp:feature</code> element is used to specify
-infomation about support and usage requirements for a particular feature.</p><a id="elt-syntax-feature"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:feature</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttp:feature
-  extends = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  restricts = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  value = (optional|required|<span class="obsoleted">use</span>|prohibited) : <em>see prose below</em>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA
-&lt;/ttp:feature&gt;
-</pre></div>
-</td></tr></tbody></table><p>The children of the <code>ttp:feature</code> element must express a non-empty
-sequence of <a href="#terms-character-information-item">character information items</a> the concatenation of which adheres to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17.</p><p>If specified, the <code>extends</code> attribute and/or the <code>restricts</code>
-attribute must (1) adhere to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17, and
-(2) express a feature designation as defined by
-<a href="#feature-designations"><b>E.1 Feature Designations</b></a>.</p><p>The <code>extends</code> attribute may be used to indicate that the feature being defined
-is, from either (or both) a syntactic or (and) semantic perspective, a proper superset of the
-feature referenced by the <code>extends</code> attribute.
-The <code>restricts</code> attribute may be used to indicate that the feature being defined
-is, from either (or both) a syntactic or (and) semantic perspective, a proper subset of the
-feature referenced by the <code>restricts</code> attribute.
-If an <code>extends</code> attribute is specified, then a <code>restricts</code> attribute must
-not be specified on a <code>ttp:feature</code> element; likewise, if a <code>restricts</code> attribute
-is specified, then an <code>extends</code> attribute must not be specified.</p><p>If the URI expressed by (1) the content of the <code>ttp:feature</code>
-element, (2) the <code>extends</code> attribute, or (3) the <code>restricts</code> attribute
-is a relative URI, then, when combined with the
-feature namespace value expressed by the
-<code>xml:base</code> attribute of the
-nearest ancestor <code>ttp:features</code> element, it must express an
-absolute URI.  In either case (original absolute URI or resulting
-absolutized URI), the URI expressed by the <code>ttp:feature</code>
-element must further adhere to the syntax of a feature designation as
-defined by <a href="#feature-designations"><b>E.1 Feature Designations</b></a>, and, furthermore,
-the specific designation that appears in this URI, i.e., the portion of the feature designation
-that starts with the fragment identifier separator '#', must
-be defined by this specification or some published version thereof (that
-has achieved REC status).</p><p>If the URI expressed by the content of the <code>ttp:feature</code> element,
-by the <code>extends</code> attribute, or by the <code>restricts</code> attribute
-is a relative URI, then an <code>xml:base</code> attribute should be
-specified on the nearest ancestor <code>ttp:features</code> element.</p><p>The <code>value</code> attribute specifies constraints on support for or use of
-the designated feature according to the profile type.</p><p>If the profile is a <a href="#terms-processor-profile">processor profile</a>
-then the following semantics apply:</p><ul><li><p>
-if the value of the <code>value</code> attribute
-is <code>optional</code>, then a processor may but need
-not implement or otherwise support the feature in order to process the document;
-</p></li><li><p>if the value is <code>required</code>, then perform the following steps:</p><ol class="enumar"><li><p>if the feature is implemented or otherwise supported by a processor, then continue processing
-the document;</p></li><li><p>otherwise, if
-(1) the <code>extends</code> attribute is specified on the root <code>tt</code> element,
-(2) the value of the <code>extends</code> attribute designates a feature that is implemented or otherwise supported by
-a processor, and
-(3) the computed value of the <a href="#profile-attribute-permitFeatureNarrowing"><code>ttp:permitFeatureNarrowing</code></a>
-profile property of the root <code>tt</code> element is not <code>false</code>,
-then continue processing the document;</p></li><li><p>otherwise, if
-(1) the <code>restricts</code> attribute is specified on the root <code>tt</code> element,
-(2) the value of the <code>restricts</code> attribute designates a feature that is implemented or otherwise supported by
-a processor, and
-(3) the computed value of the <a href="#profile-attribute-permitFeatureWidening"><code>ttp:permitFeatureWidening</code></a>
-profile property of the root <code>tt</code> element is not <code>false</code>,
-then continue processing the document;</p></li><li><p>otherwise, abort processing the document unless overridden by the end-user or some implementation specific parameter
-traceable to an end-user or to a user or system configuration setting.</p></li></ol></li><li><p>
-if the value attribute is not specified, then the feature specification
-must be interpreted as if the value <code>required</code> were specified;
-</p></li></ul><p>If the profile is a <a href="#terms-content-profile">content profile</a>
-then the following semantics apply:</p><ul><li><p>
-if the value of the <code>value</code> attribute
-is <code>optional</code>, then the feature may but need not appear in a document that
-claims conformance with that profile;
-</p></li><li><p>
-if the value of the <code>value</code> attribute
-is <code>required</code>, then the feature must appear in a document that
-claims conformance with that profile;
-</p></li><li><p>
-if the value of the <code>value</code> attribute
-is <code>prohibited</code>, then the feature must not appear in a document that
-claims conformance with that profile;
-</p></li><li><p>
-if the value attribute is not specified, then the feature specification
-must be interpreted as if the value <code>optional</code> were specified;
-</p></li></ul><p>The value <span class="obsoleted"><code>use</code></span> of the <code>value</code> attribute is <span class="obsoleted">obsoleted</span>. If it
-appears in a profile specification, then it must be interpreted as if <code>required</code>
-had been specified.</p><p>If some defined (i.e., standardized) or otherwise well known feature is not specified by
-a <code>ttp:feature</code> element in a content profile, then it must be interpreted as if the feature were specified
-with the <code>value</code> attribute equal to <code>optional</code>. However, if not specified in a processor profile, no claim
-about support or absence of support for the feature is implied.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In particular, if some feature is not present in a content profile definition, then
-it is not to be interpreted as meaning the use of that feature (in a <a href="#terms-document-instance">document instance</a>)
-is disallowed or otherwise prohibited. If a feature is intended to be disallowed by a content profile, then
-it should be specified using the <code>prohibited</code> value.</p></div><p>If a <a href="#terms-document-instance">document instance</a> makes use of a feature defined by
-<a href="#feature-designations"><b>E.1 Feature Designations</b></a> and if the intended use of the
-document requires the recognition and processing of that feature, then
-the document must include a <em>required</em> feature specification in one of its declared or
-referenced profiles.</p><p>The <code>ttp:feature</code> element is illustrated by the following example.</p><a id="profile-vocabulary-feature-example-1"></a><table class="example"><caption>Example Fragment – ttp:feature</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttp:profile use="http://www.w3.org/ns/ttml/profile/ttml2-presentation"&gt;
-  &lt;ttp:features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-    <span class="strong">&lt;ttp:feature value="required"&gt;#fontStyle-italic&lt;/ttp:feature&gt;</span>
-    <span class="strong">&lt;ttp:feature value="required"&gt;#textDecoration-under&lt;/ttp:feature&gt;</span>
-    <span class="strong">&lt;ttp:feature value="prohibited"&gt;#textOutline-blurred&lt;/ttp:feature&gt;</span>
-  &lt;/ttp:features&gt;
-&lt;/ttp:profile&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the TTML presentation profile is used as the
-baseline profile. This baseline profile is then modified by three
-<code>ttp:feature</code> elements in order to (1)
-superset the baseline profile (since neither
-<code>#fontStyle-italic</code> nor <code>#textDecoration-under</code>
-are required by the TTML presentation profile), and
-(2) prohibit use of the <code>#textOutline-blurred</code> feature
-(which is optional in the TTML presentation profile).</p><p>The effect of this example is to express authorial intentions that
-italic font style and text underlining must be
-supported, and that text outline blurring must not be used by a document.</p></div></div><div class="div3">
-<h4><a id="profile-vocabulary-extensions"></a>6.1.4 ttp:extensions</h4><p>The <code>ttp:extensions</code> element is a container element used to group
-infomation about extension support and usage requirements.</p><p>The <code>ttp:extensions</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by
-zero or more <code>ttp:extension</code> elements.</p><a id="elt-syntax-extensions"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:extensions</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttp:extensions
-  xml:base = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a> : <em>TT Extension Namespace</em>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#profile-vocabulary-extension">ttp:extension</a>*
-&lt;/ttp:extensions&gt;
-</pre></div>
-</td></tr></tbody></table><p>If specified, the <code>xml:base</code>
-attribute must (1) adhere to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17, (2) express an absolute URI that
-adheres to <a href="#xmlbase">[XML Base]</a> and,
-(3) express an extension namespace as defined by
-<a href="#extension-designations"><b>F.1 Extension Designations</b></a>. If not specified, the
-<code>xml:base</code> attribute's default
-value applies, which is the TT Extension Namespace.</p><p>The <code>xml:base</code> attribute is
-used to permit the abbreviation of feature designation URIs expressed
-by child <code>ttp:extension</code> elements.</p></div><div class="div3">
-<h4><a id="profile-vocabulary-extension"></a>6.1.5 ttp:extension</h4><p>The <code>ttp:extension</code> element is used to specify
-infomation about support and usage requirements for a particular extension.</p><a id="elt-syntax-extension"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:extension</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttp:extension
-  extends = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  restricts = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  value = (optional|required|<span class="obsoleted">use</span>|prohibited) : <em>see prose below</em>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA
-&lt;/ttp:extension&gt;
-</pre></div>
-</td></tr></tbody></table><p>The children of the <code>ttp:extension</code> element must express a non-empty
-sequence of <a href="#terms-character-information-item">character information items</a> the concatenation of which adheres to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17.</p><p>If specified, the <code>extends</code> attribute and/or the <code>restricts</code>
-attribute must (1) adhere to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17, and
-(2) express a feature designation or extension designation as defined by
-<a href="#feature-designations"><b>E.1 Feature Designations</b></a> or <a href="#extension-designations"><b>F.1 Extension Designations</b></a>, respectively.</p><p>The <code>extends</code> attribute may be used to indicate that the extension being defined
-is, from either (or both) a syntactic or (and) semantic perspective, a proper superset of the
-feature or extension referenced by the <code>extends</code> attribute.
-The <code>restricts</code> attribute may be used to indicate that the extension being defined
-is, from either (or both) a syntactic or (and) semantic perspective, a proper subset of the
-feature or extension referenced by the <code>restricts</code> attribute.
-If an <code>extends</code> attribute is specified, then a <code>restricts</code> attribute must
-not be specified on a <code>ttp:extension</code> element; likewise, if a <code>restricts</code> attribute
-is specified, then an <code>extends</code> attribute must not be specified.</p><p>If the URI expressed by (1) the content of the <code>ttp:extension</code>
-element, (2) the <code>extends</code> attribute, or (3) the <code>restricts</code> attribute
-is a relative URI, then, when combined with the
-extension namespace value expressed by the
-<code>xml:base</code> attribute of the
-nearest ancestor <code>ttp:extensions</code> element, it must express an
-absolute URI.  In either case (original absolute URI or resulting
-absolutized URI), the URI expressed by the <code>ttp:extension</code>
-element must further adhere to the syntax of an extension designation as
-defined by <a href="#extension-designations"><b>F.1 Extension Designations</b></a>,
-while the URI expressed by the <code>extends</code> attribute and/or the
-<code>restricts</code> attribute must adhere to the syntax of a feature designation
-or an extension designation as defined by <a href="#feature-designations"><b>E.1 Feature Designations</b></a> or
-<a href="#extension-designations"><b>F.1 Extension Designations</b></a>, respectively.</p><p>If the URI expressed by the content of the <code>ttp:extension</code> element,
-by the <code>extends</code> attribute, or by the <code>restricts</code> attribute
-is a relative URI, then an <code>xml:base</code> attribute should be
-specified on the nearest ancestor <code>ttp:extensions</code> element.</p><p>The <code>value</code> attribute specifies constraints on support for or use of
-the designated extension according to the profile type.</p><p>If the profile is a <a href="#terms-processor-profile">processor profile</a>
-then the following semantics apply:</p><ul><li><p>
-if the value of the <code>value</code> attribute
-is <code>optional</code>, then a processor may but need
-not implement or otherwise support the extension in order to process the document;
-</p></li><li><p>if the value is <code>required</code>, then perform the following steps:</p><ol class="enumar"><li><p>if the extension is implemented or otherwise supported by a processor, then continue processing
-the document;</p></li><li><p>otherwise, if
-(1) the <code>extends</code> attribute is specified on the root <code>tt</code> element,
-(2) the value of the <code>extends</code> attribute designates an extension that is implemented or otherwise supported by
-a processor, and
-(3) the computed value of the <a href="#profile-attribute-permitFeatureNarrowing"><code>ttp:permitFeatureNarrowing</code></a>
-profile property of the root <code>tt</code> element is not <code>false</code>,
-then continue processing the document;</p></li><li><p>otherwise, if
-(1) the <code>restricts</code> attribute is specified on the root <code>tt</code> element,
-(2) the value of the <code>restricts</code> attribute designates an extension that is implemented or otherwise supported by
-a processor, and
-(3) the computed value of the <a href="#profile-attribute-permitFeatureWidening"><code>ttp:permitFeatureWidening</code></a>
-profile property of the root <code>tt</code> element is not <code>false</code>,
-then continue processing the document;</p></li><li><p>otherwise, abort processing the document unless overridden by the end-user or some implementation specific parameter
-traceable to an end-user or to a user or system configuration setting.</p></li></ol></li><li><p>
-if the value attribute is not specified, then the extension specification
-must be interpreted as if the value <code>required</code> were specified;
-</p></li></ul><p>If the profile is a <a href="#terms-content-profile">content profile</a>
-then the following semantics apply:</p><ul><li><p>
-if the value of the <code>value</code> attribute
-is <code>optional</code>, then the extension may but need not appear in a document that
-claims conformance with that profile;
-</p></li><li><p>
-if the value of the <code>value</code> attribute
-is <code>required</code>, then the extension must appear in a document that
-claims conformance with that profile;
-</p></li><li><p>
-if the value of the <code>value</code> attribute
-is <code>prohibited</code>, then the extension must not appear in a document that
-claims conformance with that profile;
-</p></li><li><p>
-if the value attribute is not specified, then the extension specification
-must be interpreted as if the value <code>optional</code> were specified;
-</p></li></ul><p>The value <span class="obsoleted"><code>use</code></span> of the <code>value</code> attribute is <span class="obsoleted">obsoleted</span>. If it
-appears in a profile specification, then it must be interpreted as if <code>required</code>
-had been specified.</p><p>If some well known extension is not specified by
-a <code>ttp:extension</code> element in a content profile, then it must be interpreted as if the extension were specified
-with the <code>value</code> attribute equal to <code>optional</code>. However, if not specified in a processor profile, no claim
-about support or absence of support for the extension is implied.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In particular, if some extension is not present in a content profile definition, then
-it is not to be interpreted as meaning the use of that extension (in a <a href="#terms-document-instance">document instance</a>)
-is disallowed or otherwise prohibited. If an extension is intended to be disallowed by a content profile, then
-it should be specified using the <code>prohibited</code> value.</p></div><p>If a <a href="#terms-document-instance">document instance</a> makes use
-of an extension designatable by <a href="#extension-designations"><b>F.1 Extension Designations</b></a> and if the intended use of the document
-requires the recognition and processing of that extension, then the
-document must include a <em>required</em> extension specification
-in one of its declared or referenced profiles.</p><p>The <code>ttp:extension</code> element is illustrated by the following example.</p><a id="profile-vocabulary-extension-example-1"></a><table class="example"><caption>Example Fragment – ttp:extension</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttp:profile use="http://www.w3.org/ns/ttml/profile/ttml2-transformation"&gt;
-  &lt;ttp:extensions xml:base="http://example.org/ttml/extension/"&gt;
-    <span class="strong">&lt;ttp:extension value="use"&gt;#prefilter-by-language&lt;/ttp:extension&gt;</span>
-  &lt;/ttp:extensions&gt;
-&lt;/ttp:profile&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the TTML transformation profile is used as
-the baseline profile. This baseline profile is then supersetted by
-specifying that support and use is required for a private extension
-defined in a third party namespace.</p><p>The effect of this example is to express authorial intentions that
-a recipient processor must support the TTML transformation profile and
-must also support and enable an extension defined by a third party.</p></div></div></div><div class="div2">
-<h3><a id="profile-attribute-vocabulary"></a>6.2 Profile Attribute Vocabulary</h3><p>The following attributes are defined in the TT Parameter Namespace.</p><ul><li><p><a href="#profile-attribute-contentProfiles"><b>6.2.1 ttp:contentProfiles</b></a></p></li><li><p><a href="#profile-attribute-contentProfileCombination"><b>6.2.2 ttp:contentProfileCombination</b></a></p></li><li><p><a href="#profile-attribute-inferProcessorProfileMethod"><b>6.2.3 ttp:inferProcessorProfileMethod</b></a></p></li><li><p><a href="#profile-attribute-inferProcessorProfileSource"><b>6.2.4 ttp:inferProcessorProfileSource</b></a></p></li><li><p><a href="#profile-attribute-permitFeatureNarrowing"><b>6.2.5 ttp:permitFeatureNarrowing</b></a></p></li><li><p><a href="#profile-attribute-permitFeatureWidening"><b>6.2.6 ttp:permitFeatureWidening</b></a></p></li><li><p><a href="#profile-attribute-profile"><b>6.2.7 ttp:profile</b></a></p></li><li><p><a href="#profile-attribute-processorProfiles"><b>6.2.8 ttp:processorProfiles</b></a></p></li><li><p><a href="#profile-attribute-processorProfileCombination"><b>6.2.9 ttp:processorProfileCombination</b></a></p></li><li><p><a href="#profile-attribute-validation"><b>6.2.10 ttp:validation</b></a></p></li><li><p><a href="#profile-attribute-validationAction"><b>6.2.11 ttp:validationAction</b></a></p></li><li><p><a href="#profile-attribute-version"><b>6.2.12 ttp:version</b></a></p></li></ul><p>Unless explicitly stated otherwise, linear white-space (LWSP) must
-appear between adjacent non-terminal components of a TT Parameter value
-unless some other delimiter is permitted and used.</p><div class="div3">
-<h4><a id="profile-attribute-contentProfiles"></a>6.2.1 ttp:contentProfiles</h4><p>The <code>ttp:contentProfiles</code> attribute may be used by a content author
-to express one or more <a href="#terms-content-profile">content profiles</a> of
-the Timed Text Markup Language (TTML) where the
-<a href="#terms-enclosing-document-instance">enclosing document instance</a> claims conformance to any or all of the
-specified <a href="#terms-content-profile">content profiles</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax,
-where each <code>profile-designator</code> item adheres to the <code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17, and, further, adheres to constraints defined on a profile designator in accordance with
-<a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>.</p><a id="profile-attribute-contentProfiles-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:contentProfiles</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:contentProfiles
-  : designators
-  | "all(" designators ")"
-  | "any(" designators ")"
-
-designators
-  : designator (lwsp designator)*
-
-designator
-  : xsd:anyURI
-
-lwsp
-  : ( ' ' | '\t' | '\n' | '\r' )+
-</pre></div>
-</td></tr></tbody></table><p>If the list of designators is enclosed in the function syntax <code>all(...)</code> or no function syntax is used,
-then conformance is claimed with all designated <a href="#terms-content-profile">content profiles</a>. If the list
-of designators is enclosed in the function syntax <code>any(...)</code>, then conformance is claimed with at least one
-of the designated <a href="#terms-content-profile">content profiles</a>.</p><p>A <code>ttp:contentProfiles</code>
-attribute is considered to be significant only when specified on the
-<code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-contentProfileCombination"></a>6.2.2 ttp:contentProfileCombination</h4><p>The <code>ttp:contentProfileCombination</code> attribute is used to specify the
-method for combining multiple <a href="#terms-content-profile">content profiles</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-contentProfileCombination-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:contentProfileCombination</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:contentProfileCombination
-  : "leastRestrictive"
-  | "mostRestrictive"
-  | "replace"
-</pre></div>
-</td></tr></tbody></table><p>Given two ordered profile specification values, <em>arg1</em> and <em>arg2</em>, and a content profile combination method,
-<a href="#content-profile-combination-table"><b>Table 6-1 – Content Profile Combination</b></a> specifies the result of combining the two specification values, where the order
-of arguments is determined in accordance with the lexical order of
-<a href="#terms-content-profile">content profiles</a> in a <a href="#terms-document-instance">document instance</a>.</p><a id="content-profile-combination-table"></a><table class="common"><caption>Table 6-1 – Content Profile Combination</caption><col width="16.67%" span="1"><col width="16.67%" span="1"><col width="22%" span="1"><col width="22%" span="1"><col width="22%" span="1"><tbody><tr><th><em>arg1</em></th><th><em>arg2</em></th><th><code>leastRestrictive</code></th><th><code>mostRestrictive</code></th><th><code>replace</code></th></tr><tr><td>optional</td><td>optional</td><td>optional</td><td>optional</td><td>optional</td></tr><tr><td>optional</td><td>required</td><td>optional</td><td>required</td><td>required</td></tr><tr><td>optional</td><td>prohibited</td><td>optional</td><td>prohibited</td><td>prohibited</td></tr><tr><td>required</td><td>optional</td><td>optional</td><td>required</td><td>optional</td></tr><tr><td>required</td><td>required</td><td>required</td><td>required</td><td>required</td></tr><tr><td>required</td><td>prohibited</td><td>required</td><td>prohibited</td><td>prohibited</td></tr><tr><td>prohibited</td><td>optional</td><td>optional</td><td>prohibited</td><td>optional</td></tr><tr><td>prohibited</td><td>required</td><td>required</td><td>prohibited</td><td>required</td></tr><tr><td>prohibited</td><td>prohibited</td><td>prohibited</td><td>prohibited</td><td>prohibited</td></tr></tbody></table><p>A <code>ttp:contentProfileCombination</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-inferProcessorProfileMethod"></a>6.2.3 ttp:inferProcessorProfileMethod</h4><p>The <code>ttp:inferProcessorProfileMethod</code> attribute is used to specify the
-method for mapping a content profile specification value to a corresponding processor
-profile specification value.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-inferProcessorProfileMethod-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:inferProcessorProfileMethod</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:inferProcessorProfileMethod
-  : "loose"
-  | "strict"
-</pre></div>
-</td></tr></tbody></table><p>If this parameter's value is <code>loose</code>, then, when inferring a processor profile specification from a content profile specification,
-a loose (liberal) mapping applies.</p><p>If this parameter's value is <code>strict</code>, then, when inferring a processor profile specification from a content profile specification,
-a strict (conservative) mapping applies.</p><p>If not specified, the value of this parameter must be considered
-to be <code>loose</code>.</p><p>Given an input content profile specification value, <em>input</em>, and an infer processor profile method,
-<a href="#infer-processor-profile-method-table"><b>Table 6-2 – Infer Processor Profile Method</b></a> specifies the result of mapping the input specification value.</p><a id="infer-processor-profile-method-table"></a><table class="common"><caption>Table 6-2 – Infer Processor Profile Method</caption><col width="33%" span="1"><col width="33%" span="1"><col width="33%" span="1"><tbody><tr><th><em>input</em></th><th><code>loose</code></th><th><code>strict</code></th></tr><tr><td>optional</td><td>optional</td><td>required</td></tr><tr><td>required</td><td>required</td><td>required</td></tr><tr><td>prohibited</td><td>optional</td><td>optional</td></tr></tbody></table><p>A <code>ttp:inferProcessorProfileMethod</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-inferProcessorProfileSource"></a>6.2.4 ttp:inferProcessorProfileSource</h4><p>The <code>ttp:inferProcessorProfileSource</code> attribute is used to specify the
-source for mapping a content profile specification value to a corresponding processor
-profile specification value.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-inferProcessorProfileSource-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:inferProcessorProfileSource</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:inferProcessorProfileSource
-  : "combined"
-  | "first"
-</pre></div>
-</td></tr></tbody></table><p>If this parameter's value is <code>combined</code>, then, when inferring a processor profile, the combined profile specification
-set of the <a href="#terms-effective-content-profile">effective content profile</a> is used as the source of inference.</p><p>If this parameter's value is <code>first</code>, then, when inferring a processor profile, the first constituent profile of
-the <a href="#terms-effective-content-profile">effective content profile</a>, where the processor profile inferred from that
-constituent profile is supported by the <a href="#terms-content-processor">content processor</a>, is used as the source of inference.</p><p>If not specified, the value of this parameter must be considered
-to be <code>combined</code>.</p><p>A <code>ttp:inferProcessorProfileSource</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-permitFeatureNarrowing"></a>6.2.5 ttp:permitFeatureNarrowing</h4><p>The <code>ttp:permitFeatureNarrowing</code> attribute is used to specify whether
-requirements related to a feature or extension may be satisfied by a (syntactically or semantically) narrower interpretation
-of the feature or extension.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-permitFeatureNarrowing-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:permitFeatureNarrowing</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:permitFeatureNarrowing
-  : <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:boolean</a>                             // see <a href="#xsd-2">[XML Schema Part 2]</a>, §3.2.2
-</pre></div>
-</td></tr></tbody></table><p>If this parameter's value is <code>true</code>, then, a requirement for support of a feature or extension may be satisfied
-if the definition of the feature or extension specifies an <code>extends</code> attribute, and the feature or extension referenced
-by that attribute is supported by a processor.</p><p>If this parameter's value is <code>false</code>, then, a requirement for support of a feature or extension can not be satisfied
-by a more narrowly defined feature or extension specified by an <code>extends</code> attribute.</p><p>If not specified, the value of this parameter must be considered
-to be <code>false</code>.</p><p>A <code>ttp:permitFeatureNarrowing</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-permitFeatureWidening"></a>6.2.6 ttp:permitFeatureWidening</h4><p>The <code>ttp:permitFeatureWidening</code> attribute is used to specify whether
-requirements related to a feature or extension may be satisfied by a (syntactically or semantically) wider interpretation
-of the feature or extension.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-permitFeatureWidening-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:permitFeatureWidening</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:permitFeatureWidening
-  : <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:boolean</a>                             // see <a href="#xsd-2">[XML Schema Part 2]</a>, §3.2.2
-</pre></div>
-</td></tr></tbody></table><p>If this parameter's value is <code>true</code>, then, a requirement for support of a feature or extension may be satisfied
-if the definition of the feature or extension specifies an <code>restricts</code> attribute, and the feature or extension referenced
-by that attribute is supported by a processor.</p><p>If this parameter's value is <code>false</code>, then, a requirement for support of a feature or extension can not be satisfied
-by a more widely defined feature or extension specified by an <code>restricts</code> attribute.</p><p>If not specified, the value of this parameter must be considered
-to be <code>false</code>.</p><p>A <code>ttp:permitFeatureWidening</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-profile"></a>6.2.7 ttp:profile</h4><p>The <code>ttp:profile</code> attribute is <span class="deprecated">deprecated</span>. If creating a TTML document instance for TTML2 (or later versions),
-then the <code>ttp:profile</code> attribute should not be used; instead, the content author should use the <code>ttp:processorProfiles</code>
-attribute, specified at <a href="#profile-attribute-processorProfiles"><b>6.2.8 ttp:processorProfiles</b></a>.</p><p>If used in a document, the <code>ttp:profile</code> attribute
-denotes a <a href="#terms-processor-profile">processor profile</a>
-of the Timed Text Markup Language (TTML) that applies when processing
-a <a href="#terms-document-instance">document instance</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For information on signaling content profile(s), see <a href="#profile-attribute-contentProfiles"><b>6.2.1 ttp:contentProfiles</b></a>.</p></div><p>If specified, the value of this attribute must adhere to the following syntax
-where the <code>designator</code> adheres to the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17, and, further, must specify a
-profile designator in accordance with
-<a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>.</p><a id="profile-attribute-profile-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:profile</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-<span class="deprecated">ttp:profile</span>
-  : designator
-
-designator
-  : xsd:anyURI
-</pre></div>
-</td></tr></tbody></table><p>A <code>ttp:profile</code>
-attribute is considered to be significant only when specified on the
-<code>tt</code> element.</p><p>If a <a href="#terms-top-level-profile">top-level</a> <a href="#terms-processor-profile">processor profile</a>
-is defined in a <a href="#terms-document-instance">document instance</a>, then the
-<a href="#profile-attribute-profile"><code>ttp:profile</code></a>
-attribute should not be specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-processorProfiles"></a>6.2.8 ttp:processorProfiles</h4><p>The <code>ttp:processorProfiles</code> attribute may be used by a content author
-to express one or more <a href="#terms-processor-profile">processor profiles</a> of
-the Timed Text Markup Language (TTML) where the
-<a href="#terms-enclosing-document-instance">enclosing document instance</a> requires support for each and all
-specified <a href="#terms-processor-profile">processor profiles</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax,
-where each <code>profile-designator</code> item adheres to the <code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§3.2.17, and, further, adheres to constraints defined on a profile designator in accordance with
-<a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>.</p><a id="profile-attribute-processorProfiles-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:processorProfiles</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:processorProfiles
-  : designators
-  | "all(" designators ")"
-  | "any(" designators ")"
-
-designators
-  : designator (lwsp designator)*
-
-designator
-  : xsd:anyURI
-
-lwsp
-  : ( ' ' | '\t' | '\n' | '\r' )+
-</pre></div>
-</td></tr></tbody></table><p>If the list of designators is enclosed in the function syntax <code>all(...)</code> or no function syntax is used,
-then support is required for all designated <a href="#terms-processor-profile">processor profiles</a>. If the list
-of designators is enclosed in the function syntax <code>any(...)</code>, then support is required for at least one
-of the designated <a href="#terms-processor-profile">processor profiles</a>.</p><p>A <code>ttp:processorProfiles</code>
-attribute is considered to be significant only when specified on the
-<code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-processorProfileCombination"></a>6.2.9 ttp:processorProfileCombination</h4><p>The <code>ttp:processorProfileCombination</code> attribute is used to specify the
-method for combining multiple <a href="#terms-processor-profile">processor profiles</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-processorProfileCombination-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:processorProfileCombination</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:processorProfileCombination
-  : "leastRestrictive"
-  | "mostRestrictive"
-  | "replace"
-</pre></div>
-</td></tr></tbody></table><p>Given two ordered profile specification values, <em>arg1</em> and <em>arg2</em>, and a processor profile combination method,
-<a href="#processor-profile-combination-table"><b>Table 6-3 – Processor Profile Combination</b></a> specifies the result of combining the two specification values, where the order
-of arguments is determined in accordance with the lexical order of
-<a href="#terms-processor-profile">processor profiles</a> in a <a href="#terms-document-instance">document instance</a>.</p><a id="processor-profile-combination-table"></a><table class="common"><caption>Table 6-3 – Processor Profile Combination</caption><col width="16.67%" span="1"><col width="16.67%" span="1"><col width="22%" span="1"><col width="22%" span="1"><col width="22%" span="1"><tbody><tr><th><em>arg1</em></th><th><em>arg2</em></th><th><code>leastRestrictive</code></th><th><code>mostRestrictive</code></th><th><code>replace</code></th></tr><tr><td>optional</td><td>optional</td><td>optional</td><td>optional</td><td>optional</td></tr><tr><td>optional</td><td>required</td><td>optional</td><td>required</td><td>required</td></tr><tr><td>required</td><td>optional</td><td>optional</td><td>required</td><td>optional</td></tr><tr><td>required</td><td>required</td><td>required</td><td>required</td><td>required</td></tr></tbody></table><p>A <code>ttp:processorProfileCombination</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-validation"></a>6.2.10 ttp:validation</h4><p>The <code>ttp:validation</code> attribute is used to specify whether validation processing
-may or must be performed on a <a href="#terms-document-instance">document instance</a> by a
-<a href="#terms-validating-content-processor">validating content processor</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-validation-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:validation</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:validation
-  : "required"
-  | "optional"
-  | "prohibited"
-</pre></div>
-</td></tr></tbody></table><p>If this parameter's value is <code>required</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
-must perform validation processing on a TTML <a href="#terms-document-instance">document instance</a> prior to performing
-other types of processing, e.g., presentation or transformation processing.</p><p>If this parameter's value is <code>optional</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
-may, but need not, perform validation processing on a TTML <a href="#terms-document-instance">document instance</a> prior to performing
-other types of processing, e.g., presentation or transformation processing.</p><p>If this parameter's value is <code>prohibited</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
-must not perform validation processing on a TTML <a href="#terms-document-instance">document instance</a> prior to performing
-other types of processing, e.g., presentation or transformation processing, unless the end-user or application overrides this prohibition.</p><p>If validation processing is performed on a TTML <a href="#terms-document-instance">document instance</a> and validation fails, then the computed value of
-the <code>ttp:validationAction</code> parameter property is used to determine what action to take before performing further processing.</p><p>If not specified, the value of this parameter must be considered
-to be <code>optional</code>.</p><p>A <code>ttp:validation</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-validationAction"></a>6.2.11 ttp:validationAction</h4><p>The <code>ttp:validationAction</code> attribute is used to specify what action is to be taken
-by a <a href="#terms-validating-content-processor">validating content processor</a> when
-validation of a <a href="#terms-document-instance">document instance</a> fails.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-validationAction-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:validationAction</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:validationAction
-  : "abort"
-  | "warn"
-  | "ignore"
-</pre></div>
-</td></tr></tbody></table><p>If this parameter's value is <code>abort</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
-must abort processing of a TTML <a href="#terms-document-instance">document instance</a> when validation processing fails.</p><p>If this parameter's value is <code>warn</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
-should warn the end-user when validation processing fails, and, give the end-user the option to continue or abort processing.</p><p>If this parameter's value is <code>ignore</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
-should not abort and should not warn the end-user when validation processing fails.</p><p>If not specified, the value of this parameter is determined as follows:
-if the computed value of the <a href="#profile-attribute-validation"><code>ttp:validation</code></a> parameter property is <code>required</code>,
-then the value must be considered to be <code>abort</code>;
-if it is <code>optional</code>,
-then the value must be considered to be <code>warn</code>;
-otherwise, if it is <code>prohibited</code>,
-then the value must be considered to be <code>ignore</code>.</p><p>A <code>ttp:validationAction</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="profile-attribute-version"></a>6.2.12 ttp:version</h4><p>The <code>ttp:version</code> attribute is used to specify which version of the
-<a href="#terms-timed-text-markup-language">Timed Text Markup Language</a>
-specification was used in authoring a TTML <a href="#terms-document-instance">document instance</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-version-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:version</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:version
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+                                // <em>value</em> &gt; 0
-</pre></div>
-</td></tr></tbody></table><p>A <code>ttp:version</code> attribute must be specified on the root <code>tt</code>
-element of a <a href="#terms-document-instance">document instance</a> if it
-requires support for a <a href="#terms-feature">feature</a> not defined by <a href="#ttml1">[TTML1]</a>.</p><p>If not specified, the version must be considered to be
-equal to one (1). If specified, then the version must be greater than zero (0). The version associated
-with this version of the <a href="#terms-timed-text-markup-language">Timed Text Markup Language</a>
-specification is two (2).</p><p>A <code>ttp:version</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <a href="#terms-content-processor">content processor</a> typically uses the
-declared version to perform a preliminary assessment of whether it is capable of
-processing a given <a href="#terms-document-instance">document instance</a>.
-However, it does not assume that the <a href="#terms-document-instance">document instance</a>
-actually uses or requires support for a <a href="#terms-feature">feature</a>
-not defined in prior versions. In other
-words, a <a href="#terms-content-processor">content processor</a> does not reject
-a <a href="#terms-document-instance">document instance</a> simply because it declares
-it was authored against a version of the <a href="#terms-timed-text-markup-language">Timed Text Markup Language</a>
-specification that was not yet published at the time the processor was implemented.</p><p>The computed value of the parameter property expresssed by the <code>ttp:version</code> attribute is used by the
-<a href="#semantics-procedure-construct-default-processor-profile"><span class="strong">construct default processor profile</span></a>
-procedure to determine the <a href="#terms-default-processor-profile">default processor profile</a>.</p></div></div></div></div><div class="div1">
-<h2><a id="parameter"></a>7 Parameter</h2><p>This section specifies the <em>parameter</em> matter of the
-core vocabulary catalog, where
-parameters are to be understood as information that is either (1)
-essential or (2) of significant importance for the purpose of
-interpreting the semantics of other types of information expressed by
-core vocabulary items or for establishing a <a href="#terms-document-processing-context">document processing context</a> by means
-of which TTML Content can be related to an external environment.</p><div class="div2">
-<h3><a id="parameter-element-vocabulary"></a>7.1 Parameter Element Vocabulary</h3><p>No parameter element vocabulary is defined in this specification.</p></div><div class="div2">
-<h3><a id="parameter-attribute-vocabulary"></a>7.2 Parameter Attribute Vocabulary</h3><p>The following attributes are defined in the TT Parameter Namespace.</p><ul><li><p><a href="#parameter-attribute-cellResolution"><b>7.2.1 ttp:cellResolution</b></a></p></li><li><p><a href="#parameter-attribute-clockMode"><b>7.2.2 ttp:clockMode</b></a></p></li><li><p><a href="#parameter-attribute-dropMode"><b>7.2.3 ttp:dropMode</b></a></p></li><li><p><a href="#parameter-attribute-frameRate"><b>7.2.4 ttp:frameRate</b></a></p></li><li><p><a href="#parameter-attribute-frameRateMultiplier"><b>7.2.5 ttp:frameRateMultiplier</b></a></p></li><li><p><a href="#parameter-attribute-markerMode"><b>7.2.6 ttp:markerMode</b></a></p></li><li><p><a href="#parameter-attribute-mediaDuration"><b>7.2.7 ttp:mediaDuration</b></a></p></li><li><p><a href="#parameter-attribute-mediaOffset"><b>7.2.8 ttp:mediaOffset</b></a></p></li><li><p><a href="#parameter-attribute-pixelAspectRatio"><b>7.2.9 ttp:pixelAspectRatio</b></a></p></li><li><p><a href="#parameter-attribute-storageAspectRatio"><b>7.2.10 ttp:storageAspectRatio</b></a></p></li><li><p><a href="#parameter-attribute-subFrameRate"><b>7.2.11 ttp:subFrameRate</b></a></p></li><li><p><a href="#parameter-attribute-tickRate"><b>7.2.12 ttp:tickRate</b></a></p></li><li><p><a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a></p></li></ul><p>Unless explicitly stated otherwise, linear white-space (LWSP) must
-appear between adjacent non-terminal components of a TT Parameter value
-unless some other delimiter is permitted and used.</p><div class="div3">
-<h4><a id="parameter-attribute-cellResolution"></a>7.2.1 ttp:cellResolution</h4><p>The <code>ttp:cellResolution</code> attribute may be used by an author
-to express the number of horizontal and vertical cells into which the <a href="#terms-root-container-region">root container region</a>
-area is divided for the purpose of expressing presentation semantics in terms of
-a uniform grid.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-cellResolution-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:cellResolution</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:cellResolution
-  : columns rows                            // <em>columns</em> != 0; <em>rows</em> != 0
-
-columns | rows
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-</pre></div>
-</td></tr></tbody></table><p>If not specified, the number of columns and rows must be considered
-to be 32 and 15, respectively. If specified, then columns or rows must not be zero (0).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The choice of values 32 and 15 are based on this being the
-maximum number of columns and rows defined by <a href="#cea608e">[CEA-608-E]</a>.</p></div><p>A <code>ttp:cellResolution</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of a uniform grid is employed only for the purpose of
-measuring lengths and expressing coordinates. In particular, it is not
-assumed that the presentation of text or the alignment of individual
-glyph areas is
-coordinated with this grid. Such alignment is possible, but
-requires the use of a monospaced font and a font size whose EM square exactly
-matches the cell size.</p></div><p>Except where indicated otherwise, when a <a href="#style-value-length">&lt;length&gt;</a> expressed in
-cells denotes a dimension parallel to the inline or block progression dimension,
-the cell's dimension in the inline or block progression dimension applies, respectively.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, if padding (on all four edges) is specified as 0.1c, the cell resolution
-is 20 by 10, and the extent of the <a href="#terms-root-container-region">root container region</a> is 640 by 480, then, assuming top to bottom,
-left to right writing mode, the start and end padding will be (640 / 20) * 0.1 pixels and the
-before and after padding will be (480 / 10) * 0.1 pixels.</p></div></div><div class="div3">
-<h4><a id="parameter-attribute-clockMode"></a>7.2.2 ttp:clockMode</h4><p>The <code>ttp:clockMode</code> attribute is used to specify the
-interpretation of time expressions as real-time time coordinates when
-operating with time base of <code>clock</code> as defined by <a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#timing-time-value-expressions"><b>12.3 Time Value Expressions</b></a> for the
-specification of time expression syntax and semantics.</p></div><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-clockMode-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:clockMode</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:clockMode
-  : "local"
-  | "gps"
-  | "utc"
-</pre></div>
-</td></tr></tbody></table><p>If the time base, defined by <a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>, is designated as
-<code>clock</code>, then this parameter applies as follows: if the
-parameter's value is <code>local</code>, then time expressions are
-interpreted as local wall-clock time coordinates;
-if <code>utc</code>, then time expressions are
-interpreted as UTC time coordinates
-<a href="#utc">[UTC]</a>;
-if <code>gps</code>, then time expressions are
-interpreted as GPS time coordinates
-<a href="#gps">[GPS]</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The primary difference between GPS time and UTC time is that GPS
-time is not adjusted for leap seconds, while UTC time is adjusted as
-follows: UTC = TAI (<em>Temp Atomique International</em>) + <em>leap seconds
-accumulated since 1972</em>. TAI is maintained by the <em>Bureau
-International des Poids et Mesures</em> (BIPM) in Sevres, France.
-The GPS system time is steered to a Master Clock (MC) at the US Naval
-Observatory which is kept within a close but unspecified
-tolerance of TAI.</p></div><p>If not specified, the value of this parameter must be considered
-to be <code>utc</code>.</p><p>A <code>ttp:clockMode</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="parameter-attribute-dropMode"></a>7.2.3 ttp:dropMode</h4><p>The <code>ttp:dropMode</code> attribute is used to specify
-constraints on the interpretation and use of frame counts
-that correspond with <a href="#smpte12m">[SMPTE 12M]</a> time coordinates when operating
-with time base of <code>smpte</code> as defined by
-<a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-dropMode-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:dropMode</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:dropMode
-  : "dropNTSC"
-  | "dropPAL"
-  | "nonDrop"
-</pre></div>
-</td></tr></tbody></table><p>If the time base, defined by <a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>, is designated as
-<code>smpte</code>, then this parameter applies as follows: if the
-parameter's value is <code>nonDrop</code>, then, within any given
-second of a time expression, frames count from 0 to
-<em>N−1</em>, where <em>N</em> is the value specified by
-the <code>ttp:frameRate</code> parameter, but while ignoring any value
-specified by the <code>ttp:frameRateMultiplier</code> parameter.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When operating in <code>nonDrop</code>
-mode, a second of a time expression may or may not be equal to a
-second of real time during normal (1x speed) forward playback. If the
-<code>ttp:frameRateMultiplier</code> parameter is specified and is not
-equal to 1:1, then a second of a time expression will either be
-shorter or longer than a second of elapsed play in real
-time.</p></div><p>If this parameter's value is <code>dropNTSC</code>, then, within any
-given second of a time expression except the second <code>00</code>,
-frames count from 0 to <em>N−1</em>, where <em>N</em> is
-the value specified by the <code>ttp:frameRate</code> parameter, but
-while ignoring any value specified by the
-<code>ttp:frameRateMultiplier</code> parameter. If the second of a time
-expression is <code>00</code> and the minute of the time expression is
-not <code>00</code>, <code>10</code>, <code>20</code>, <code>30</code>,
-<code>40</code>, or <code>50</code>, then frame codes <code>00</code>
-and <code>01</code> are dropped during that second; otherwise, these
-frame codes are not dropped.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, when operating in <code>dropNTSC</code>
-mode with <code>ttp:frameRate</code> of <code>30</code>, a discontinuity
-in frame count occurs between consecutive frames as shown in the
-following sequence of time expressions: <code>01:08:59:28</code>,
-<code>01:08:59:29</code>, <code>01:09:00:02</code>,
-<code>01:09:00:03</code>.</p></div><p>If this parameter's value is <code>dropPAL</code>, then, within any
-given second of a time expression except the second <code>00</code>,
-frames count from 0 to <em>N−1</em>, where <em>N</em> is
-the value specified by the <code>ttp:frameRate</code> parameter, but
-while ignoring any value specified by the
-<code>ttp:frameRateMultiplier</code> parameter. If the second of a time
-expression is <code>00</code> and the minute of the time expression is
-even but not <code>00</code>, <code>20</code>, or <code>40</code>,
-then frame codes <code>00</code> through <code>03</code> are dropped
-during that second; otherwise, these frame codes are not dropped.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, when operating in <code>dropPAL</code>
-mode with <code>ttp:frameRate</code> of <code>30</code>, a discontinuity
-in frame count occurs between consecutive frames as shown in the
-following sequence of time expressions: <code>01:09:59:28</code>,
-<code>01:09:59:29</code>, <code>01:10:00:04</code>,
-<code>01:10:00:05</code>.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The <code>dropPAL</code> mode is also known as the
-<em>M/PAL</em> or <em>PAL (M)</em> drop-frame
-code, which uses PAL modulation with the NTSC frame rate of ~29.97
-frames/second. The M/PAL system is used primarily in Brazil.</p></div><p>If not specified, then <code>nonDrop</code> must be assumed to apply.</p><p>A <code>ttp:dropMode</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="parameter-attribute-frameRate"></a>7.2.4 ttp:frameRate</h4><p>The <code>ttp:frameRate</code> attribute is used to specify the frame rate of a related
-media object or the intrinsic frame rate of a <a href="#terms-document-instance">document instance</a> in case it is intended
-to function as an independent media object.</p><div class="issue"><p class="prefix"><a id="issue-333"></a><b>Issue (issue-333):</b></p><p class="prefix"><b>Defaulting Frame Rate Multiplier, Sub Frame Rate</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/333">http://www.w3.org/AudioVideo/TT/tracker/issues/333</a></p><p>If frame rate is defaulted to processing environment, then frame rate multiplier and sub frame rate should be as well.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-frameRate-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:frameRate</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:frameRate
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+                                // <em>value</em> &gt; 0
-</pre></div>
-</td></tr></tbody></table><p>The frame rate that applies to a <a href="#terms-document-instance">document instance</a> is used to
-interpret time expressions that are expressed in <em>frames</em>
-as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>If the <code>media</code> time base applies and the effective frame rate is
-integral, then a frame is interpreted as a division of a second of media
-time, such that if the frame rate is specified as <em>F</em>, then
-a second of media time is divided into <em>F</em> intervals of
-equal duration, where each interval is labeled as frame <em>f</em>,
-with <em>f</em> ∈ [0…<em>F−1</em>].</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> for further details
-on the interpretation of time expressions for the <code>media</code> time base.</p></div><p>If not specified, the frame rate must be considered to be equal to some
-application defined frame rate, or if no application defined frame rate applies,
-then thirty (30) frames per second. If specified, then the frame rate must
-be greater than zero (0).</p><p>A <code>ttp:frameRate</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="parameter-attribute-frameRateMultiplier"></a>7.2.5 ttp:frameRateMultiplier</h4><p>The <code>ttp:frameRateMultiplier</code> attribute is used to
-specify a multiplier to be applied to the frame rate specified by a
-<code>ttp:frameRate</code> attribute in order to compute the effective
-frame rate.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-frameRateMultiplier-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:frameRateMultiplier</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:frameRateMultiplier
-  : numerator denominator                   // <em>numerator</em> != 0; <em>denominator</em> != 0
-
-numerator | denominator
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-</pre></div>
-</td></tr></tbody></table><p>A frame rate multiplier is used when the desired frame rate cannot
-be expressed as an integral number of frames per second.</p><p>If not specified, the frame rate multiplier must be considered to be equal to one (1:1).
-Both numerator and denominator must be non-zero.</p><p>A <code>ttp:frameRateMultiplier</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The frame rate multiplier used for synchronizing with NTSC <a href="#smpte170m">[SMPTE 170M]</a>
-formatted video objects at 30 frames per second is nominally
-1000:1001. The nominal frame rate of NTSC video is defined as the chrominance
-sub-carrier frequency of 3,579,545.45…Hz (= 5.0MHz × 63/88) times the ratio 2/455 divided by
-the number of horizontal lines per frame of 525, which yields a frame
-rate of 29.970029970029… (= 30 × 1000/1001) frames per
-second. Other frame rate multipliers apply to different regions of
-usage and video format standards.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Except in the case of PAL/M, the frame rate multiplier used for synchronizing with PAL
-formatted video objects at 25 frames per second is nominally 1:1.</p></div></div><div class="div3">
-<h4><a id="parameter-attribute-markerMode"></a>7.2.6 ttp:markerMode</h4><p>The <code>ttp:markerMode</code> attribute is used to specify
-constraints on the interpretation and use of time expressions
-that correspond with <a href="#smpte12m">[SMPTE 12M]</a> time coordinates when operating
-with time base of <code>smpte</code> as defined by
-<a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-markerMode-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:markerMode</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:markerMode
-  : "continuous"
-  | "discontinuous"
-</pre></div>
-</td></tr></tbody></table><p>If the time base, defined by <a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>, is designated as
-<code>smpte</code>, then this parameter applies as follows: if the
-parameter's value is <code>continuous</code>, then <a href="#smpte12m">[SMPTE 12M]</a> time coordinates
-may be assumed to be linear and either monotonically increasing or
-decreasing; however, if <code>discontinuous</code>, then any assumption
-must not be made regarding linearity or monotonicity of time coordinates.</p><p>If not specified, the value of this parameter must be considered
-to be <code>discontinuous</code>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The default value for this parameter was originally specified
-(in <a href="http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/">TTML 1.0 First Edition</a>)
-as <code>continuous</code>; however, further evaluation of the state of the industry indicated this
-choice was incorrect, and that the most common default is <code>discontinuous</code>.</p></div><p>A <code>ttp:markerMode</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p><p>If a value of <code>continuous</code> applies, then time
-expressions may be converted to real time
-coordinates by taking into account the computed frame rate
-and drop mode as expressed by the <code>ttp:dropMode</code> parameter.
-In this case, the <a href="#terms-content-processor">content processor</a> must create and maintain a
-<a href="#terms-synthetic-smpte-document-syncbase">synthetic smpte document syncbase</a> within which these time
-expressions are interpreted as further described in
-<a href="#semantics-timing"><b>12.4 Timing Semantics</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When operating with <code>smpte</code> time base and
-<code>continuous</code> marker mode, there is an implied time coordinate
-space, the <a href="#terms-synthetic-smpte-document-syncbase">synthetic smpte document syncbase</a>,
-defined by the monotonically increasing (or decreasing) 
-<a href="#smpte12m">[SMPTE 12M]</a> time coordinates, while taking into account
-the computed frame rate and drop mode. All time expressions are interpreted
-in relationship to this time coordinate space based upon
-<a href="#terms-smpte-time-code">smpte time code</a> synchronization events (markers),
-where the <a href="#terms-document-processing-context">document processing context</a> emits these events with implied constraints
-regarding time coordinate monoticity and resynchronization in
-the presence of dropped frames.</p><p>Use of <code>continuous</code> marker mode with the <code>smpte</code>
-time base is different from using the <code>media</code> time base
-because (1) the semantics of the <code>ttp:dropMode</code> parameter
-apply to the former, but not the latter, and (2) <a href="#smpte12m">[SMPTE 12M]</a>
-time coordinates may be applied monotonically to media which has been
-subjected to dilation in time, constriction in time, or reversal in
-time.</p></div><p>If a value of <code>discontinuous</code> applies, then time
-expressions must not be converted to real time
-coordinates, arithmetical operators (addition, multiplication) are not
-defined on time expressions, and, consequently, any (well-formed)
-expression of a duration must be considered to be invalid.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When operating with <code>smpte</code> time base and
-<code>discontinuous</code> marker mode, there is no effective time coordinate
-space; rather, all time expressions are interpreted as labeled
-synchronization events (markers), where the <a href="#terms-document-processing-context">document processing context</a>
-emits these events, which, when they correspond with time
-expressions that denote the same label, cause a temporal interval to
-begin or end accordingly.</p><p>An additional side-effect of operating in <code>discontinuous</code>
-mode is that time expressions of children have no necessary
-relationship with time expressions of their temporal container; that
-is, temporal containers and children of these containers are
-temporally activated and inactivated independently based on the
-occurrence of a labeled synchronization (marker) event.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The notion of marker discontinuity as captured by this parameter
-is logically independent from the method used to count frames as
-expressed by the <code>ttp:dropMode</code> parameter. In particular,
-even if the <code>ttp:dropMode</code> parameter is specified as
-<code>dropNTSC</code> or <code>dropPAL</code>, the marker mode may be
-specified as <code>continuous</code>, even in the presence of frame count
-discontinuities induced by the frame counting method, unless there
-were some other non-linearity or discontinuity in marker labeling, for
-example, two consecutive frames labeled as <code>10:00:00:00</code>
-and <code>10:00:01:00</code>.
-</p></div></div><div class="div3">
-<h4><a id="parameter-attribute-mediaDuration"></a>7.2.7 ttp:mediaDuration</h4><p>The <code>ttp:mediaDuration</code> attribute is used to specify the
-temporal extent (simple duration) of a <a href="#terms-related-media-object">related media object</a>.</p><p>If the temporal extent (simple duration) of the <a href="#terms-related-media-object">related media object</a> is known at authoring time, then this
-attribute should be specified; otherwise, if no <a href="#terms-related-media-object">related media object</a> applies or its
-temporal extent is unknown, then this attribute should not be specified.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-mediaDuration-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:mediaDuration</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:mediaDuration
-  : <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>                        // restricted to <em>offset-time</em> form
-  | "indefinite"
-</pre></div>
-</td></tr></tbody></table><p>If specified, the value of this parameter must either (1) adhere to the <em>offset-time</em> form of
-a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> or (2) take the value <code>indefinite</code>.</p><p>If the value <code>indefinite</code> is specified, then there is no <a href="#terms-related-media-object">related media object</a>,
-the temporal extent (simple duration) of the
-<a href="#terms-related-media-object">related media object</a> is not known at the time this attribute is
-encoded, or the <a href="#terms-related-media-object">related media object</a> has no temporal end point.</p><p>If not specified, the value of this parameter must be considered
-to be <code>indefinite</code>.</p><p>A <code>ttp:mediaDuration</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#timing-time-value-expressions"><b>12.3 Time Value Expressions</b></a> for the
-specification of time expression syntax and semantics.</p></div></div><div class="div3">
-<h4><a id="parameter-attribute-mediaOffset"></a>7.2.8 ttp:mediaOffset</h4><p>The <code>ttp:mediaOffset</code> attribute is used to specify the
-temporal offset between the begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a>
-and the begin time of a <a href="#terms-related-media-object">related media object</a> when operating in a
-<a href="#time-expression-semantics-media">Media Time Base</a>
-or a <a href="#time-expression-semantics-smpte">SMPTE Time Base</a>. It does not apply and
-must not be specified when operating in a <a href="#time-expression-semantics-clock">Clock Time Base</a>.</p><div class="issue"><p class="prefix"><a id="issue-270"></a><b>Issue (issue-270):</b></p><p class="prefix"><b>Media Time Offset</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/270">http://www.w3.org/AudioVideo/TT/tracker/issues/270</a></p><p>Tie up loose ends with respect to definition of media time offset, particulary regarding the definition of the origin and beginning of
-the document temporal extent.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><div class="issue"><p class="prefix"><a id="issue-335"></a><b>Issue (issue-335):</b></p><p class="prefix"><b>Media Time Offset</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/335">http://www.w3.org/AudioVideo/TT/tracker/issues/335</a></p><p>Tie up loose ends with respect to definition of media time offset, particulary regarding the definition of the origin and beginning of
-the document temporal extent.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-mediaOffset-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:mediaOffset</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:mediaOffset
-  : sign? <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>                  // restricted to <em>offset-time</em> form
-
-sign
-  : "+" | "-"
-</pre></div>
-</td></tr></tbody></table><p>If specified, the value of this parameter must adhere to the <em>offset-time</em> form of
-a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> optionally expressed with a sign.
-If not specified, the value of this parameter must be considered
-to be <code>0s</code>.</p><p>If no sign is specified or it is specified as <code>+</code>, then the begin time of the
-<a href="#terms-root-temporal-extent">root temporal extent</a> follows the begin time of the
-<a href="#terms-related-media-object">related media object</a>; otherwise (sign is present and
-specified as <code>-</code>), the begin time of the
-<a href="#terms-root-temporal-extent">root temporal extent</a> precedes the begin time of the
-<a href="#terms-related-media-object">related media object</a>.</p><p>A <code>ttp:mediaOffset</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#timing-time-value-expressions"><b>12.3 Time Value Expressions</b></a> for the
-specification of time expression syntax and semantics.</p></div></div><div class="div3">
-<h4><a id="parameter-attribute-pixelAspectRatio"></a>7.2.9 ttp:pixelAspectRatio</h4><p>The <code>ttp:pixelAspectRatio</code> attribute may be used to express the <a href="#terms-pixel-aspect-ratio">pixel aspect ratio</a> associated with the
-<a href="#terms-authoring-viewport">authoring viewport</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-pixelAspectRatio-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:pixelAspectRatio</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:pixelAspectRatio
-  : numerator demoninator                   // <em>numerator</em> != 0; <em>demoninator</em> != 0
-
-numerator | demoninator
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-</pre></div>
-</td></tr></tbody></table><p>If not specified, then square pixels (i.e., aspect ratio 1:1) must be assumed to apply.
-If specified, then both numerator and demoninator must be non-zero.</p><p>A <code>ttp:pixelAspectRatio</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="parameter-attribute-storageAspectRatio"></a>7.2.10 ttp:storageAspectRatio</h4><p>The <code>ttp:storageAspectRatio</code> attribute may be used to express the <a href="#terms-storage-aspect-ratio">storage aspect ratio</a> associated with the
-<a href="#terms-authoring-viewport">authoring viewport</a>.</p><div class="issue"><p class="prefix"><a id="issue-201"></a><b>Issue (issue-201):</b></p><p class="prefix"><b>Maintaining Display Aspect Ratio</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/201">http://www.w3.org/AudioVideo/TT/tracker/issues/201</a></p><p>Tie up loose ends with respect to support for retaining display aspect ratio. See also new values of <a href="#style-attribute-extent"><code>tts:extent</code></a>:
-<code>contain</code> and <code>cover</code>.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-storageAspectRatio-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:storageAspectRatio</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:storageAspectRatio
-  : numerator demoninator                   // <em>numerator</em> != 0; <em>demoninator</em> != 0
-
-numerator | demoninator
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-</pre></div>
-</td></tr></tbody></table><p>If specified, then both numerator and demoninator must be non-zero.
-If not specified, then the storage aspect ratio of the <a href="#terms-authoring-viewport">authoring viewport</a> is undefined.</p><p>A <code>ttp:storageAspectRatio</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="parameter-attribute-subFrameRate"></a>7.2.11 ttp:subFrameRate</h4><p>The <code>ttp:subFrameRate</code> attribute is used to specify the sub-frame rate of a related
-media object or the intrinsic sub-frame rate of a <a href="#terms-document-instance">document instance</a> in case it is intended
-to function as an independent media object.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-subFrameRate-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:subFrameRate</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:subFrameRate
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+                                // <em>value</em> &gt; 0
-</pre></div>
-</td></tr></tbody></table><p>The sub-frame rate that applies to a <a href="#terms-document-instance">document instance</a> is used to
-interpret time expressions that are expressed in <em>sub-frames</em>
-as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>If the <code>media</code> time base applies and the effective frame rate is
-integral, a sub-frame is interpreted as a division of a frame of media
-time, such that if the sub-frame rate is specified as <em>S</em>, then
-a frame of media time is divided into <em>S</em> intervals of
-equal duration, where each interval is labeled as sub-frame <em>s</em>,
-with <em>s</em> ∈ [0…<em>S−1</em>].</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> for further details
-on the interpretation of time expressions for the <code>media</code> time base.</p></div><p>If not specified, the sub-frame rate must be considered to be
-equal to one (1). If specified, then the sub-frame rate must be greater than zero (0).</p><p>A <code>ttp:subFrameRate</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The sub-frame is sometimes referred to as a <em>field</em> in
-the context of synchronization with an interlaced video media object.</p></div></div><div class="div3">
-<h4><a id="parameter-attribute-tickRate"></a>7.2.12 ttp:tickRate</h4><p>The <code>ttp:tickRate</code> attribute is used to specify the tick rate of a related
-media object or the intrinsic tick rate of content of a <a href="#terms-document-instance">document instance</a> in case it is intended
-to function as an independent media object.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-tickRate-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:tickRate</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:tickRate
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+                                // <em>value</em> &gt; 0
-</pre></div>
-</td></tr></tbody></table><p>The tick rate that applies to a <a href="#terms-document-instance">document instance</a> is used to
-interpret time expressions that are expressed in <em>ticks</em> by
-using the <code>t</code> metric as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>If the <code>media</code> time base applies,
-a tick is interpreted as an integral division of a second of media
-time, such that if the tick rate is specified as <em>T</em>, then
-a second of media time is divided into <em>T</em> intervals of
-equal duration, where each interval is labeled as tick <em>t</em>,
-with <em>t</em> ∈ [0…<em>T−1</em>].</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> for further details
-on the interpretation of time expressions for the <code>media</code> time base.</p></div><p>If not specified, then if a frame rate is specified, the tick rate
-must be considered to be the effective frame rate multiplied by the
-sub-frame rate (i.e., ticks are interpreted as sub-frames); or, if no
-frame rate is specified, the tick rate must be considered to be one (1)
-tick per second of media time. If specified, then the tick rate
-must not be zero (0).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>There is no predefined relationship between ticks and frames or
-sub-frames. Ticks are an arbitrary division of seconds that permit
-use of fixed point arithmetic rather than fractional (and potentially
-inexact) expressions of seconds.</p></div><p>A <code>ttp:tickRate</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p></div><div class="div3">
-<h4><a id="parameter-attribute-timeBase"></a>7.2.13 ttp:timeBase</h4><p>The <code>ttp:timeBase</code> attribute is used to specify the
-temporal coordinate system by means of which time expressions are
-interpreted in a <a href="#terms-document-instance">document instance</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-timeBase-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:timeBase</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttp:timeBase
-  : "media"
-  | "smpte"
-  | "clock"
-</pre></div>
-</td></tr></tbody></table><p>If the time base is designated as <code>media</code>, then a time
-expression denotes a coordinate in some media object's time line,
-where the media object may be an external media object with which the
-content of a <a href="#terms-document-instance">document instance</a> is to be synchronized, or it may
-be the content of a <a href="#terms-document-instance">document instance</a> itself in a case where
-the timed text content is intended to establish an independent time
-line.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When using a media time base, if that time base is paused or
-scaled positively or negatively, i.e., the media play rate is
-not unity, then it is expected that the
-presentation of associated Timed Text content will be similarly
-paused, accelerated, or decelerated, respectively. The means for
-controlling an external
-media time base is outside the scope of this specification.</p></div><p>If the time base is designated as <code>smpte</code>,
-then a time expression denotes a <a href="#smpte12m">[SMPTE 12M]</a> time
-coordinate with which the content of a <a href="#terms-document-instance">document instance</a> is to
-be synchronized.  In this case, the value of the <code>ttp:markerMode</code> 
-and <code>ttp:dropMode</code> parameters apply, as defined by <a href="#parameter-attribute-markerMode"><b>7.2.6 ttp:markerMode</b></a> and <a href="#parameter-attribute-dropMode"><b>7.2.3 ttp:dropMode</b></a>, respectively.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When the time base is designated as <code>smpte</code>,
-every time expression denotes a media marker value akin to that
-defined by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3, except instead
-of using an opaque marker name, a structured <a href="#smpte12m">[SMPTE 12M]</a>
-time coordinate serves as the marker name.</p></div><p>If the time base is designated as <code>clock</code>, then the time
-expression denotes a coordinate in some real-world time line as
-established by some real-time clock, such as the local wall-clock time
-or UTC (Coordinated Universal Time) or GPS (Global Positioning System)
-time lines.</p><p>If not specified, the default time base must be considered to be
-<code>media</code>.</p><p>A <code>ttp:timeBase</code> attribute is considered to be significant only
-when specified on the <code>tt</code> element.</p><p>When operating with either <code>media</code> or <code>smpte</code>
-time bases, a diachronic presentation of a <a href="#terms-document-instance">document instance</a> may
-be subject to transformations of the controlling time line, such as
-temporal reversal, dilation (expansion), or constriction
-(compression); however, when operating with the <code>clock</code>
-time base, no transformations are permitted, and diachronic
-presentation proceeds on a linear, monotonically increasing time line
-based on the passage of real time.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Due to there being only one time base parameter that applies to a
-given <a href="#terms-document-instance">document instance</a>, the interpretation of time expressions
-is uniform throughout the <a href="#terms-document-instance">document instance</a>.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#time-expression-semantics"><b>H Time Expression Semantics</b></a> for further details
-on the interpretation of time expressions according to the designated time base.</p></div></div></div></div><div class="div1">
-<h2><a id="content"></a>8 Content</h2><p>This section specifies the <em>content</em> matter of the core
-vocabulary catalog.</p><div class="div2">
-<h3><a id="content-element-vocabulary"></a>8.1 Content Element Vocabulary</h3><p>The following elements specify the structure and principal content aspects of a
-<a href="#terms-document-instance">document instance</a>:</p><ul><li><p><a href="#document-structure-vocabulary-tt"><b>8.1.1 tt</b></a></p></li><li><p><a href="#document-structure-vocabulary-head"><b>8.1.2 head</b></a></p></li><li><p><a href="#document-structure-vocabulary-body"><b>8.1.3 body</b></a></p></li><li><p><a href="#content-vocabulary-div"><b>8.1.4 div</b></a></p></li><li><p><a href="#content-vocabulary-p"><b>8.1.5 p</b></a></p></li><li><p><a href="#content-vocabulary-span"><b>8.1.6 span</b></a></p></li><li><p><a href="#content-vocabulary-br"><b>8.1.7 br</b></a></p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>The sub-sections of this section are ordered logically (from highest to lowest level construct).</p></div><div class="div3">
-<h4><a id="document-structure-vocabulary-tt"></a>8.1.1 tt</h4><p>The <code>tt</code> element serves as the root document element of a <a href="#terms-document-instance">document instance</a>.</p><p>The <code>tt</code> element accepts as its children zero or one <code>head</code> element followed by
-zero or one <code>body</code> element.</p><a id="elt-syntax-tt"></a><table class="syntax"><caption>XML Representation – Element Information Item: tt</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#style-attribute-extent">tts:extent</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#style-attribute-position">tts:position</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang"><span class="reqattr">xml:lang</span></a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>) : default
-  {<em>any attribute in TT Parameter namespace</em>}
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#document-structure-vocabulary-head">head</a>?, <a href="#document-structure-vocabulary-body">body</a>?
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p>The <a href="#terms-root-temporal-extent">root temporal extent</a>, i.e., the time interval over which a <a href="#terms-document-instance">document instance</a> is active, has an implicit duration that is equal to the
-implicit duration of the <code>body</code> element of the document, if the <code>body</code> element is present, or zero, if the <code>body</code> element is absent.</p><p>If the <a href="#style-attribute-extent"><code>tts:extent</code></a> attribute is specified on the <code>tt</code>
-element, then it must adhere to <a href="#style-attribute-extent"><b>10.2.11 tts:extent</b></a>, in which case it
-specifies the spatial extent of the <a href="#terms-root-container-region">root container region</a> in
-which <a href="#terms-content-region">content regions</a> are located and presented. If no <code>tts:extent</code>
-attribute is specified, then the spatial extent of the <a href="#terms-root-container-region">root container region</a> is
-considered to be determined by the <a href="#terms-document-processing-context">document processing context</a>.
-The origin of the <a href="#terms-root-container-region">root container region</a> is determined by the <a href="#terms-document-processing-context">document processing context</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In the absence of other requirements, and if a <a href="#terms-related-media-object">related media object</a> exists, then it is recommended
-that the <a href="#terms-document-processing-context">document processing context</a> determine that:</p><ul><li><p>if no <code>tts:extent</code> is specified on the root <code>tt</code> element, the extent of the <a href="#terms-root-container-region">root container region</a> be
-established as equal to the extent of the <a href="#terms-related-media-object-region">related media object region</a>; and</p></li><li><p>the origin of the <a href="#terms-root-container-region">root container region</a> be established so that this region is centered in the
-<a href="#terms-related-media-object-region">related media object region</a>.</p></li></ul></div><div class="note"><p class="prefix"><b>Note:</b></p><p>If an author desires to signal the (storage or image) aspect ratio of the <a href="#terms-root-container-region">root container region</a>
-without specifying its resolution, then this may be accomplished by using metadata specified
-in an external namespace, such as <code>m708:aspectRatio</code> as defined in <a href="#smpte2052">[SMPTE 2052-11]</a>, §5.4.4.
-This would permit, for example, the interchange of information that reflects the
-the semantics of <a href="#cea708e">[CEA-708-E]</a> , §4.5 “Caption Service Metadata”, “ASPECT RATIO”.</p></div><p>If the <a href="#style-attribute-position"><code>tts:position</code></a> attribute is specified on the <code>tt</code>
-element, then it must adhere to <a href="#style-attribute-position"><b>10.2.27 tts:position</b></a>, in which case it
-specifies the position of the <a href="#terms-root-container-region">root container region</a> relative to a reference positioning area.</p><p>Except for the <code>tts:extent</code> and <code>tts:position</code> attributes described above, an attribute in the TT Style Namespace should not
-be specified on the <code>tt</code> element unless it denotes an inheritable style property, in which case such inheritable style property is available
-for <a href="#semantics-style-inheritance-root">root style inheritance</a>. If a non-inheritable style property is specified, then
-it must be ignored for the purpose of non-validation processing. In the case of validation
-processing, such usage should be reported as a warning, or, if strict validation is performed, as an error.</p><p>An <code>xml:lang</code> attribute must be specified on the <code>tt</code> element.
-If the attribute value is empty, it signifies that there is no default language that applies
-to the text contained within the <a href="#terms-document-instance">document instance</a>.</p><p>If no <code>xml:space</code> attribute is specified upon the <code>tt</code> element, then it must
-be considered as if the attribute had been specified with a value of <code>default</code>.</p></div><div class="div3">
-<h4><a id="document-structure-vocabulary-head"></a>8.1.2 head</h4><p>The <code>head</code> element is a container element used to group header matter, including metadata,
-profile, embedded content resources, styling, and layout information.</p><p>The <code>head</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more elements in the
-<a href="#element-vocab-group-profile"><code>Profile.class</code></a> element group,
-followed by zero or one <a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element,
-followed by zero or one <a href="#styling-vocabulary-styling"><code>styling</code></a> element,
-followed by zero or one <a href="#layout-vocabulary-layout"><code>layout</code></a> element,
-followed by zero or one <a href="#animation-vocabulary-animation"><code>animation</code></a> element.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
-element group applies semantically to the <a href="#terms-document-instance">document instance</a> as a
-whole, and not just the <code>head</code> element.</p><p>Any parameters specified by children in the <code>Parameters.class</code>
-element group applies semantically to the <a href="#terms-document-instance">document instance</a> as a
-whole, and not just the <code>head</code> element.</p><p>A <code>resources</code> child element is used to specify embedded content constructs
-that are referenced from certain style constructs and
-<a href="#terms-embedded-content-element">embedded content elements</a>.</p><p>A <code>styling</code> child element is used to specify style constructs
-that are referenced from other style constructs, by layout constructs, and by
-<a href="#terms-content-element">content elements</a>.</p><p>A <code>layout</code> child element is used to specify layout constructs that
-are referenced by <a href="#terms-content-element">content elements</a>.</p><p>An <code>animation</code> child element is used to specify animation constructs that
-target animatable <a href="#terms-content-element">content element</a>
-or <a href="#element-vocab-type-layout">Layout</a> elements.</p><a id="elt-syntax-head"></a><table class="syntax"><caption>XML Representation – Element Information Item: head</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;head
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-profile">Profile.class</a>*, <a href="#embedded-content-vocabulary-resources">resources</a>?, <a href="#styling-vocabulary-styling">styling</a>?, <a href="#layout-vocabulary-layout">layout</a>?, <a href="#animation-vocabulary-animation">animation</a>?
-&lt;/head&gt;
-</pre></div>
-</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
-<code>head</code> element, the implied time interval of this element is
-defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div><div class="div3">
-<h4><a id="document-structure-vocabulary-body"></a>8.1.3 body</h4><p>The <code>body</code> element functions as a logical container and a temporal
-structuring element for a sequence of textual content units represented as
-logical divisions.</p><p>The <code>body</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more
-elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
-followed by
-zero or more <code>div</code> elements.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
-element group applies semantically to the <code>body</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
-element group apply semantically to the <code>body</code> element.</p><a id="elt-syntax-body"></a><table class="syntax"><caption>XML Representation – Element Information Item: body</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;body
-  <a href="#animation-attribute-animate">animate</a> = IDREFS
-  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#layout-attribute-region">region</a> = IDREF
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Metadata namespace</em>}
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, <a href="#content-vocabulary-div">div</a>*
-&lt;/body&gt;
-</pre></div>
-</td></tr></tbody></table><p>An author may specify a temporal interval for a <code>body</code> element using
-the <code>begin</code>, <code>dur</code>, and <code>end</code> attributes. If the begin point
-of this interval remains unspecified, then the begin point is interpreted as the beginning
-point of the <a href="#terms-root-temporal-extent">root temporal extent</a>. Similarly, if the end point of this interval remains unspecified, then the
-end point is interpreted as the ending point of the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <a href="#terms-document-instance">document instance</a> referenced from a SMIL presentation
-is expected to follow the same timing rules as apply to other SMIL media
-objects.</p></div><p>If relative begin or end times are specified on the <code>body</code>
-element, then these times are resolved by reference to the beginning and
-ending time of the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p><p>If the <a href="#terms-root-temporal-extent">root temporal extent</a> is shorter than the computed duration of the
-<code>body</code> element, then the active time interval of a <code>body</code> element is
-truncated to the active end point of the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p><p>An author may associate a set of style properties with a
-<code>body</code> element by means of either the <code>style</code>
-attribute or inline style attributes or a combination thereof.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Style properties that are associated with a <code>body</code> element
-in a <a href="#terms-document-instance">document instance</a> are available for style inheritance by
-descendant <a href="#terms-content-element">content elements</a> such as <code>div</code>, <code>p</code>,
-<code>span</code>
-and <code>br</code>.</p></div><p>If no <code>timeContainer</code> attribute is specified on a
-<code>body</code> element, then it must be interpreted as having
-<em>parallel</em>
-time containment semantics.</p></div><div class="div3">
-<h4><a id="content-vocabulary-div"></a>8.1.4 div</h4><p>The <code>div</code> element functions as a logical container and a temporal
-structuring element for a sequence of textual content units represented as
-logical sub-divisions or paragraphs.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When rendered on a continuous (non-paged) visual presentation medium,
-a <code>div</code> element is expected to generate
-one or more block
-areas
-that contain zero or more child block areas
-generated by the <code>div</code> element's
-descendant
-<code>p</code> elements.
-</p><p>If some
-block area generated by a <code>div</code> element does
-not contain any child areas, then it is not expected to be presented.</p></div><p>The <code>div</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more
-elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
-followed by zero or one
-element in the <a href="#element-vocab-group-layout"><code>Layout.class</code></a> element group,
-followed by zero or more elements in the <a href="#element-vocab-group-block"><code>Block.class</code></a> or
-<a href="#element-vocab-group-embedded"><code>Embedded.class</code></a> element groups.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
-element group applies semantically to the <code>div</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
-element group apply semantically to the <code>div</code> element.</p><a id="elt-syntax-div"></a><table class="syntax"><caption>XML Representation – Element Information Item: div</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;div
-  <a href="#animation-attribute-animate">animate</a> = IDREFS
-  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#layout-attribute-region">region</a> = IDREF
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Metadata namespace</em>}
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, <a href="#element-vocab-group-layout">Layout.class</a>?, (<a href="#element-vocab-group-block">Block.class</a>|<a href="#element-vocab-group-embedded">Embedded.class</a>)*
-&lt;/div&gt;
-</pre></div>
-</td></tr></tbody></table><p>An author may associate a set of style properties with a <code>div</code> element by means of either
-the <code>style</code> attribute or inline style attributes or a combination thereof.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Style properties that are associated
-with
-a <code>div</code> element in a <a href="#terms-document-instance">document instance</a>
-are available for style inheritance by descendant <a href="#terms-content-element">content elements</a> such as
-<code>div</code>, 
-<code>p</code>,
-<code>span</code>, and
-<code>br</code>.</p></div><p>If a
-<a href="#style-attribute-position"><code>tts:extent</code></a>,
-<a href="#style-attribute-position"><code>tts:origin</code></a>, or
-<a href="#style-attribute-position"><code>tts:position</code></a>
-style attribute is specified on a <code>div</code> element, then that specification must be considered to be
-equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>div</code> element, where the
-extent, origin, or position of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
-value of the respective attribute. If any of these style attributes are specified,
-then they apply to the same <a href="#terms-implied-inline-region">implied inline region</a>.
-If both <a href="#style-attribute-position"><code>tts:origin</code></a> and <a href="#style-attribute-position"><code>tts:position</code></a> attributes
-are specified and <a href="#style-attribute-position"><code>tts:position</code></a> is a supported property,
-then the <a href="#style-attribute-position"><code>tts:origin</code></a> attribute must be ignored when constructing the associated
-<a href="#terms-implied-inline-region">implied inline region</a>.</p><p>If no <code>timeContainer</code> attribute is specified on
-a <code>div</code> element, then it must be interpreted as having
-<em>parallel</em> time containment semantics.</p></div><div class="div3">
-<h4><a id="content-vocabulary-p"></a>8.1.5 p</h4><p>A <code>p</code> element represents a logical paragraph, serving as
-a transition between block level and inline level formatting semantics.</p><p>The <code>p</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more
-elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
-followed by zero or one
-element in the <a href="#element-vocab-group-layout"><code>Layout.class</code></a> element group,
-followed by zero or more elements in the <a href="#element-vocab-group-inline"><code>Inline.class</code></a> or
-<a href="#element-vocab-group-embedded"><code>Embedded.class</code></a> element groups.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
-element group applies semantically to the <code>p</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
-element group apply semantically to the <code>p</code> element.</p><a id="elt-syntax-p"></a><table class="syntax"><caption>XML Representation – Element Information Item: p</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;p
-  <a href="#animation-attribute-animate">animate</a> = IDREFS
-  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#layout-attribute-region">region</a> = IDREF
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Metadata namespace</em>}
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, <a href="#element-vocab-group-layout">Layout.class</a>?, (<a href="#element-vocab-group-inline">Inline.class</a>|<a href="#element-vocab-group-embedded">Embedded.class</a>)*
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p>An author may associate a set of style properties with a
-<code>p</code> element by means of either the <code>style</code>
-attribute or inline style attributes or a combination thereof.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Style properties that are associated with a <code>p</code> element
-in a <a href="#terms-document-instance">document instance</a> are available for style inheritance by
-descendant <a href="#terms-content-element">content elements</a> such as <code>span</code> and
-<code>br</code>.</p></div><p>If a
-<a href="#style-attribute-position"><code>tts:extent</code></a>,
-<a href="#style-attribute-position"><code>tts:origin</code></a>, or
-<a href="#style-attribute-position"><code>tts:position</code></a>
-style attribute is specified on a <code>p</code> element, then that specification must be considered to be
-equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>p</code> element, where the
-extent, origin, or position of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
-value of the respective attribute. If any of these style attributes are specified,
-then they apply to the same <a href="#terms-implied-inline-region">implied inline region</a>.
-If both <a href="#style-attribute-position"><code>tts:origin</code></a> and <a href="#style-attribute-position"><code>tts:position</code></a> attributes
-are specified and <a href="#style-attribute-position"><code>tts:position</code></a> is a supported property,
-then the <a href="#style-attribute-position"><code>tts:origin</code></a> attribute must be ignored when constructing the associated
-<a href="#terms-implied-inline-region">implied inline region</a>.</p><p>If no <code>timeContainer</code> attribute is specified on
-a <code>p</code> element, then it must be interpreted as having
-<em>parallel</em> time containment semantics.</p><p>If a sequence of children of a <code>p</code> element
-consists solely of <a href="#terms-character-information-item">character information items</a>, then that sequence must
-be considered to be an <em>anonymous span</em> for the purpose of
-applying style properties that apply to <code>span</code> elements.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The presentation semantics of TTML effectively
-implies that a <code>p</code> element constitutes a line break. In particular,
-it is associated with a block-stacking constraint both before the first
-generated line area and after the last generated line area. See
-<a href="#semantics-region-layout-step-2"><b>11.3.1.4 Synchronic Flow Processing</b></a> for further details.</p></div></div><div class="div3">
-<h4><a id="content-vocabulary-span"></a>8.1.6 span</h4><p>The <code>span</code> element functions as a logical container and a temporal
-structuring element for a sequence of textual content units having inline
-level formatting semantics.</p><p>When presented on a visual medium, a <code>span</code> element is intended to
-generate a sequence of inline areas, each containing one or more glyph areas.</p><p>The <code>span</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more
-elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
-followed by zero or more elements in the <a href="#element-vocab-group-inline"><code>Inline.class</code></a> or
-<a href="#element-vocab-group-embedded"><code>Embedded.class</code></a> element groups.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
-element group applies semantically to the <code>span</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
-element group apply semantically to the <code>span</code> element.</p><a id="elt-syntax-span"></a><table class="syntax"><caption>XML Representation – Element Information Item: span</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;span
-  <a href="#animation-attribute-animate">animate</a> = IDREFS
-  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#layout-attribute-region">region</a> = IDREF
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
-  <a href="#content-attribute-xlink-arcrole">xlink:arcrole</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>+
-  <a href="#content-attribute-xlink-href">xlink:href</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-  <a href="#content-attribute-xlink-role">xlink:role</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>+
-  <a href="#content-attribute-xlink-show">xlink:show</a> = (<em>new</em>|<em>replace</em>|<em>embed</em>|<em>other</em>|<em>none</em>) : new
-  <a href="#content-attribute-xlink-title">xlink:title</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Metadata namespace</em>}
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, (<a href="#element-vocab-group-inline">Inline.class</a>|<a href="#element-vocab-group-embedded">Embedded.class</a>)*
-&lt;/span&gt;
-</pre></div>
-</td></tr></tbody></table><p>An author may associate a set of style properties with a
-<code>span</code> element by means of either the <code>style</code>
-attribute or inline style attributes or a combination thereof.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Style properties that are associated with a <code>span</code> element
-in a <a href="#terms-document-instance">document instance</a> are available for style inheritance by
-descendant <a href="#terms-content-element">content elements</a> such as <code>span</code> and
-<code>br</code>.</p></div><p>If no <code>timeContainer</code> attribute is specified on
-a <code>span</code> element, then it must be interpreted as having
-<em>parallel</em> time containment semantics.</p><p>The linking attributes <code>xlink:*</code> may be used to link a <code>span</code> element with related content, using the
-specified location (<code>href</code>), roles, and title. The behavior of link activation is affected by the <code>xlink:show</code> attribute,
-the precise meaning of which is determined by the <a href="#terms-document-processing-context">document processing context</a>.</p><p>If a <code>span</code> element specifies an <code>xlink:href</code> attribute, then a nested <code>span</code> element descendant must not specify
-an <code>xlink:href</code> attribute, and, if it does, then the latter must be ignored for the purpose of presentation or activation processing.</p></div><div class="div3">
-<h4><a id="content-vocabulary-br"></a>8.1.7 br</h4><p>The <code>br</code> element denotes an explicit line break.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
-element group applies semantically to the <code>br</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
-element group apply semantically to the <code>br</code> element.</p><a id="elt-syntax-br"></a><table class="syntax"><caption>XML Representation – Element Information Item: br</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;br
-  <a href="#animation-attribute-animate">animate</a> = IDREFS
-  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#layout-attribute-region">region</a> = IDREF
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Metadata namespace</em>}
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*
-&lt;/br&gt;
-</pre></div>
-</td></tr></tbody></table><p>When presented on a visual medium, the presence of a <code>br</code> element must be
-interpreted as a forced line break.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The visual presentation of a <code>br</code> element is
-intended to produce the same effect as the control character
-<code>CR</code> (U+000D)
-followed by the control code <code>LF</code> (U+000A) when presented on a teletype device.
-Therefore, two <code>br</code> elements in sequence will produce a
-different effect than a single <code>br</code> element.</p></div><p>If no <code>timeContainer</code> attribute is specified on
-a <code>br</code> element, then it must be interpreted as having
-<em>parallel</em> time containment semantics.</p></div></div><div class="div2">
-<h3><a id="content-attribute-vocabulary"></a>8.2 Content Attribute Vocabulary</h3><p>This section defines the following common attributes used with many or all element types
-in the core vocabulary catalog:</p><ul><li><p><a href="#content-attribute-condition"><b>8.2.1 condition</b></a></p></li><li><p><a href="#content-attribute-xml-id"><b>8.2.7 xml:id</b></a></p></li><li><p><a href="#content-attribute-xml-lang"><b>8.2.8 xml:lang</b></a></p></li><li><p><a href="#content-attribute-xml-space"><b>8.2.9 xml:space</b></a></p></li></ul><p>In addition, this section defines the following linking vocabulary used by certain element types
-in the core vocabulary catalog:</p><ul><li><p><a href="#content-attribute-xlink-arcrole"><b>8.2.2 xlink:arcrole</b></a></p></li><li><p><a href="#content-attribute-xlink-href"><b>8.2.3 xlink:href</b></a></p></li><li><p><a href="#content-attribute-xlink-role"><b>8.2.4 xlink:role</b></a></p></li><li><p><a href="#content-attribute-xlink-show"><b>8.2.5 xlink:show</b></a></p></li><li><p><a href="#content-attribute-xlink-title"><b>8.2.6 xlink:title</b></a></p></li></ul><div class="div3">
-<h4><a id="content-attribute-condition"></a>8.2.1 condition</h4><p>The <code>condition</code> attribute is used to conditionally exclude an element from semantic processing.</p><p>The <code>condition</code> attribute may be used with any element in the core vocabulary catalog
-except profile matter, i.e., elements of the <a href="#element-vocab-type-profile">Profile Module</a>.</p><p>The value of a <code>condition</code> attribute must adhere to a
-<a href="#content-value-condition">&lt;condition&gt;</a> expression.</p><p>For the purpose of presentation processing, if an element specifies a <code>condition</code> attribute, and the
-its <a href="#content-value-condition">&lt;condition&gt;</a> expression value evaluates to <code>false</code>,
-then the semantics of the element and its descendant elements must be ignored.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, if a <a href="#content-vocabulary-p"><code>p</code></a> element specifies a <code>condition</code>
-attribute that evaluates to <code>false</code>, then the content of that element is ignored for presentation purposes.</p></div></div><div class="div3">
-<h4><a id="content-attribute-xlink-arcrole"></a>8.2.2 xlink:arcrole</h4><p>The <code>xlink:arcrole</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:arcrole</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
-<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
-<h4><a id="content-attribute-xlink-href"></a>8.2.3 xlink:href</h4><p>The <code>xlink:href</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:href</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
-<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
-<h4><a id="content-attribute-xlink-role"></a>8.2.4 xlink:role</h4><p>The <code>xlink:role</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:role</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
-<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
-<h4><a id="content-attribute-xlink-show"></a>8.2.5 xlink:show</h4><p>The <code>xlink:show</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:show</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
-<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
-<h4><a id="content-attribute-xlink-title"></a>8.2.6 xlink:title</h4><p>The <code>xlink:title</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:title</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
-<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
-<h4><a id="content-attribute-xml-id"></a>8.2.7 xml:id</h4><p>The <code>xml:id</code> attribute is used as defined by
-<a href="#xmlid">[XML ID]</a>.</p><p>The <code>xml:id</code> attribute may be used with any element in the core vocabulary catalog.</p></div><div class="div3">
-<h4><a id="content-attribute-xml-lang"></a>8.2.8 xml:lang</h4><p>The <code>xml:lang</code> attribute is used as defined by
-<a href="#xml10">[XML 1.0]</a>, §2.12, <em>Language Identification</em>.</p><p>The <code>xml:lang</code> attribute must be specified on the <code>tt</code>
-element and may be specified by an instance of any other element type
-in the core vocabulary catalog except parameter vocabulary.</p></div><div class="div3">
-<h4><a id="content-attribute-xml-space"></a>8.2.9 xml:space</h4><p>The <code>xml:space</code> attribute is used as defined by
-<a href="#xml10">[XML 1.0]</a>, §2.10, <em>White Space Handling</em>.</p><p>The <code>xml:space</code> attribute may be used with any element in
-the core vocabulary catalog except parameter vocabulary.</p><p>The semantics of the value <code>default</code> are fixed to mean that
-when performing presentation processing of a <a href="#terms-document-instance">document instance</a> as
-described by <a href="#semantics-region-layout-step-2"><b>11.3.1.4 Synchronic Flow Processing</b></a>,
-processing must occur as
-if the following properties were specified on the affected
-elements of an equivalent intermediate XSL-FO document:</p><ul><li><p><code>suppress-at-line-break="auto"</code></p></li><li><p><code>linefeed-treatment="treat-as-space"</code></p></li><li><p><code>white-space-collapse="true"</code></p></li><li><p><code>white-space-treatment="ignore-if-surrounding-linefeed"</code></p></li></ul><p>Similarly, the semantics of the value <code>preserve</code> are fixed to mean that
-when performing presentation processing, processing must occur as
-if the following properties were specified on the affected
-elements of an equivalent intermediate XSL-FO document:
-</p><ul><li><p><code>suppress-at-line-break="retain"</code></p></li><li><p><code>linefeed-treatment="preserve"</code></p></li><li><p><code>white-space-collapse="false"</code></p></li><li><p><code>white-space-treatment="preserve"</code></p></li></ul><p>When performing other types of processing intended to eventually
-result in a visual presentation by means other than those described
-in this specification, the semantics of space collapsing and
-preservation as described above should be respected. For other types
-of processing, the treatment of the <code>xml:space</code> attribute
-is processor dependent, but should respect the semantics described
-above if possible.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the above four cited XSL-FO properties are defined by
-by <a href="#xsl11">[XSL 1.1]</a>, § 7.17.3, 7.16.7, 7.16.12, and 7.16.8, respectively.</p></div></div></div><div class="div2">
-<h3><a id="content-value-expressions"></a>8.3 Content Value Expressions</h3><p>Core vocabulary may make use of the following expressions:</p><ul><li><p><a href="#content-value-arguments"><b>8.3.1 &lt;arguments&gt;</b></a></p></li><li><p><a href="#content-value-bound-parameter"><b>8.3.2 &lt;bound-parameter&gt;</b></a></p></li><li><p><a href="#content-value-condition"><b>8.3.3 &lt;condition&gt;</b></a></p></li><li><p><a href="#content-value-condition-function"><b>8.3.4 &lt;condition-function&gt;</b></a></p></li><li><p><a href="#content-value-expression"><b>8.3.5 &lt;expression&gt;</b></a></p></li><li><p><a href="#content-value-media-function"><b>8.3.6 &lt;media-function&gt;</b></a></p></li><li><p><a href="#content-value-parameter-function"><b>8.3.8 &lt;parameter-function&gt;</b></a></p></li><li><p><a href="#content-value-quoted-string"><b>8.3.7 &lt;quoted-string&gt;</b></a></p></li><li><p><a href="#content-value-supports-function"><b>8.3.9 &lt;supports-function&gt;</b></a></p></li></ul><div class="div3">
-<h4><a id="content-value-arguments"></a>8.3.1 &lt;arguments&gt;</h4><p>A &lt;arguments&gt; value is a sub-expression used with a <code>function-expression</code> non-terminal of an
-<a href="#content-value-expression">&lt;expression&gt;</a> value.</p><a id="arguments-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;arguments&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;arguments&gt;
-  : "(" ")"
-  | "(" argument-list ")"
-
-argument-list
-  : <a href="#content-value-expression">&lt;expression&gt;</a>
-  | argument-list "," <a href="#content-value-expression">&lt;expression&gt;</a>
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="content-value-bound-parameter"></a>8.3.2 &lt;bound-parameter&gt;</h4><p>A &lt;bound-parameter&gt; value is one of an enumerated collection of named parameters bound to a value by the
-<a href="#terms-content-processor">content processor</a>.</p><a id="bound-parameter-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;bound-parameter&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;bound-parameter&gt;
-  : forced
-  | mediaAspectRatio
-  | mediaLanguage
-  | userLanguage
-</pre></div>
-</td></tr></tbody></table><dl><dt class="label"><a id="bound-parameter-forced"></a><code>forced</code></dt><dd><p>Evaluates to a boolean value that denotes if the <a href="#terms-content-processor">content processor</a> is operating with
-<a href="#terms-forced-subtitle">forced subtitles</a> enabled.</p></dd><dt class="label"><a id="bound-parameter-mediaAspectRatio"></a><code>mediaAspectRatio</code></dt><dd><p>Evaluates to a numeric value equal to the aspect ratio of the <a href="#terms-related-media-object">related media object</a>.</p></dd><dt class="label"><a id="bound-parameter-mediaLanguage"></a><code>mediaLanguage</code></dt><dd><p>Evaluates to a string value equal to the (primary) language of the <a href="#terms-related-media-object">related media object</a>.</p></dd><dt class="label"><a id="bound-parameter-userLanguage"></a><code>userLanguage</code></dt><dd><p>Evaluates to a string value equal to the (primary) language of the user as determined by the
-<a href="#terms-document-processing-context">document processing context</a>.</p></dd></dl></div><div class="div3">
-<h4><a id="content-value-condition"></a>8.3.3 &lt;condition&gt;</h4><p>A &lt;condition&gt; value is used to specify an expression that evaluates to a binary value
-which is used to determine if the semantics of a
-<a href="#terms-conditionalized-element">conditionalized element</a> is respected or ignored during content processing.</p><a id="condition-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;condition&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;condition&gt;
-  : <a href="#content-value-expression">&lt;expression&gt;</a>
-</pre></div>
-</td></tr></tbody></table><p>If a &lt;condition&gt; value contains a <code>function-expression</code> non-terminal, then it must take the form
-of a <a href="#content-value-condition-function">&lt;condition-function&gt;</a> expression.</p></div><div class="div3">
-<h4><a id="content-value-condition-function"></a>8.3.4 &lt;condition-function&gt;</h4><p>A &lt;condition-function&gt; value is a sub-expression that may be used in a <a href="#content-value-condition">&lt;condition&gt;</a> value expression.</p><a id="condition-function-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;condition-function&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;condition-function&gt;
-  | <a href="#content-value-media-function">&lt;media-function&gt;</a>
-  | <a href="#content-value-parameter-function">&lt;parameter-function&gt;</a>
-  | <a href="#content-value-supports-function">&lt;supports-function&gt;</a>
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="content-value-expression"></a>8.3.5 &lt;expression&gt;</h4><p>An &lt;expression&gt; value is a sub-expression of a <a href="#content-value-condition">&lt;condition&gt;</a> value.</p><a id="expression-value-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;expression&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;expression&gt;
-  : logical-or-expression
-
-logical-or-expression
-  : logical-and-expression
-  | logical-or-expression "||" logical-and-expression
-
-logical-and-expression
-  : equality-expression
-  | logical-and-expression "&amp;&amp;" equality-expression
-
-equality-expression
-  : relational-expression
-  | equality-expression "==" relational-expression
-  | equality-expression "!=" relational-expression
-
-relational-expression
-  : additive-expression
-  | relational-expression "&lt;" additive-expression
-  | relational-expression "&gt;" additive-expression
-  | relational-expression "&lt;=" additive-expression
-  | relational-expression "&gt;=" additive-expression
-
-additive-expression
-  : multiplicitive-expression
-  | additive-expression "+" multiplicitive-expression
-  | additive-expression "-" multiplicitive-expression
-
-multiplicitive-expression
-  : unary-expression
-  | multiplicitive-expression "*" unary-expression
-  | multiplicitive-expression "/" unary-expression
-  | multiplicitive-expression "%" unary-expression
-
-unary-expression
-  : primary-or-function-expression
-  | "+" unary-expression
-  | "-" unary-expression
-  | "!" unary-expression
-
-primary-or-function-expression
-  : primary-expression
-  | function-expression
-
-primary-expression
-  : identifier
-  | literal
-  | "(" expression ")"
-
-function-expression
-  : identifier <a href="#content-value-arguments">&lt;arguments&gt;</a>
-
-identifier
-  : <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
-
-literal
-  : boolean-literal
-  | numeric-literal
-  | string-literal
-
-boolean-literal
-  : "true"
-  | "false"
-
-numeric-literal
-  : decimal-literal
-
-decimal-literal
-  : decimal-integer-literal "." decimal-digits? exponent-part?
-  | "." decimal-digits exponent-part?
-  | decimal-integer-literal exponent-part?
-
-decimal-integer-literal
-  : "0"
-  | non-zero-digit decimal-digits?
-
-decimal-digits
-  : decimal-digit
-  | decimal-digits decimal-digit
-
-decimal-digit
-  : "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8"
-
-non-zero-digit
-  : "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8"
-
-exponent-part
-  : exponent-indicator signed-integer
-
-exponent-indicator
-  : "e" | "E"
-
-signed-integer
-  : decimal-digits
-  | "+" decimal-digits
-  | "-" decimal-digits
-
-string-literal
-  : <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="content-value-media-function"></a>8.3.6 &lt;media-function&gt;</h4><p>A &lt;media-function&gt; value is a sub-expression that may be used in a <a href="#content-value-condition">&lt;condition&gt;</a> value expression
-in order to perform a media query on the <a href="#terms-related-media-object">related media object</a> or the
-<a href="#terms-document-processing-context">document processing context</a>.</p><a id="media-function-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;media-function&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;media-function&gt;
-  : "media" "(" media-query ")"
-
-media-query
-  : <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
-</pre></div>
-</td></tr></tbody></table><p>The <code>media-query</code> argument of a &lt;media-function&gt; value expression must adhere to
-the syntax of the <code>media_query_list</code> defined by <a href="#media-queries">[Media Queries]</a>, § 3.</p><p>A &lt;media-function&gt; value expression evaluates to <code>true</code> if the specified media query
-evaluates to <code>true</code>, otherwise, the value expression evaluates to <code>false</code>.</p></div><div class="div3">
-<h4><a id="content-value-quoted-string"></a>8.3.7 &lt;quoted-string&gt;</h4><p>A &lt;quoted-string&gt; value expression is used to specify a double or single quoted string.</p><a id="quoted-string-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;quoted-string&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;quoted-string&gt;
-  : double-quoted-string
-  | single-quoted-string
-
-double-quoted-string
-  : '"' ( [^"\\] | escape )+ '"'
-
-single-quoted-string
-  : "'" ( [^'\\] | escape )+ "'"
-
-escape
-  : '\\' <em>char</em>
-</pre></div>
-
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="content-value-parameter-function"></a>8.3.8 &lt;parameter-function&gt;</h4><p>A &lt;parameter-function&gt; value is a sub-expression that may be used in a <a href="#content-value-condition">&lt;condition&gt;</a> value expression
-in order to obtain a named parameter of the <a href="#terms-document-processing-context">document processing context</a>.</p><a id="parameter-function-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;parameter-function&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;parameter-function&gt;
-  : "parameter" "(" parameter-name ")"
-
-parameter-name
-  : <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
-</pre></div>
-</td></tr></tbody></table><p>When de-quoted, the <code>parameter-name</code> argument of a &lt;parameter-function&gt; value expression must adhere to an
-<a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>, which must, in turn, be one of the values enumerated
-by <a href="#content-value-bound-parameter">&lt;bound-parameter&gt;</a>.</p><p>A &lt;parameter-function&gt; value expression evaluates to the value associated with (bound to) the
-specified paramater name.</p></div><div class="div3">
-<h4><a id="content-value-supports-function"></a>8.3.9 &lt;supports-function&gt;</h4><p>A &lt;supports-function&gt; value is a sub-expression that may be used in a <a href="#content-value-condition">&lt;condition&gt;</a> value expression
-in order to obtain a boolean value that denotes whether a specified <a href="#terms-feature">feature</a> or <a href="#terms-extension">extension</a>
-is supported or not.</p><a id="supports-function-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;supports-function&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;supports-function&gt;
-  : "supports" "(" feature-or-extension-designator ")"
-
-feature-or-extension-designator
-  : <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
-</pre></div>
-</td></tr></tbody></table><p>The <code>feature-or-extension-designator</code> argument of a &lt;supports-function&gt; value expression must express
-a feature designation or an extension designation as defined by
-<a href="#feature-designations"><b>E.1 Feature Designations</b></a> and <a href="#extension-designations"><b>F.1 Extension Designations</b></a>, respectively, and where the
-<code>feature-namespace</code> or <code>extension-namespace</code> component of the designation is optional, and, if
-not specified, is considered to be equal to the <em>TT Feature Namespace</em> or <em>TT Extension Namespace</em>,
-respectively.</p><p>A &lt;supports-function&gt; value expression evaluates to <code>true</code> if the specified feature or extension
-designator is (semantically) supported by the <a href="#terms-content-processor">content processor</a>.</p></div></div></div><div class="div1">
-<h2><a id="embedded-content"></a>9 Embedded Content</h2><p>This section specifies the <em>embedded content</em> matter of the core
-vocabulary catalog, where, in this context,
-<em>content</em> is to be understood as data of an arbitrary content type (format)
-and <em>embedded</em> refers to the embedding (inlining) of this data or the embedding
-of a reference to external data.</p><div class="div2">
-<h3><a id="embedded-content-element-vocabulary"></a>9.1 Embedded Content Element Vocabulary</h3><p>The following elements may be used to specify embedded content:</p><ul><li><p><a href="#embedded-content-vocabulary-audio"><b>9.1.1 audio</b></a></p></li><li><p><a href="#embedded-content-vocabulary-chunk"><b>9.1.2 chunk</b></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><b>9.1.3 data</b></a></p></li><li><p><a href="#embedded-content-vocabulary-font"><b>9.1.4 font</b></a></p></li><li><p><a href="#embedded-content-vocabulary-image"><b>9.1.5 image</b></a></p></li><li><p><a href="#embedded-content-vocabulary-resources"><b>9.1.6 resources</b></a></p></li><li><p><a href="#embedded-content-vocabulary-source"><b>9.1.7 source</b></a></p></li></ul><p>The <a href="#embedded-content-vocabulary-data"><b>9.1.3 data</b></a> element serves as
-a generic container element for an <a href="#terms-embedded-data-resource">embedded data resource</a>, which may or may not be fragmented into chunks,
-in which case a data fragment is represented using the <a href="#embedded-content-vocabulary-chunk"><b>9.1.2 chunk</b></a> element.
-The <a href="#embedded-content-vocabulary-audio"><b>9.1.1 audio</b></a>,
-<a href="#embedded-content-vocabulary-font"><b>9.1.4 font</b></a>, and
-<a href="#embedded-content-vocabulary-image"><b>9.1.5 image</b></a> elements are specialized elements used to
-to reference specific types of embedded content.
-The <a href="#embedded-content-vocabulary-resources"><b>9.1.6 resources</b></a> element is used to
-group definitions of embedded content for reference by subsequent elements.
-The <a href="#embedded-content-vocabulary-source"><b>9.1.7 source</b></a> element may be used to
-express the source of embedded content.</p><div class="div3">
-<h4><a id="embedded-content-vocabulary-audio"></a>9.1.1 audio</h4><p>The <code>audio</code> element is used to define an author supplied <a href="#terms-audio-resource">audio resource</a>.</p><p>An <code>audio</code> element may appear in two contexts: (1) as a child of a <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element and
-(2) as a child of an element in the <a href="#element-vocab-group-block">Block.class</a> element group, namely, as a child of a
-<a href="#content-vocabulary-div"><code>div</code></a> or <a href="#content-vocabulary-p"><code>p</code></a> element, or
-as a child of a <a href="#content-vocabulary-span"><code>span</code></a> element. The former is referred to as an
-<a href="#terms-audio-defining-context">audio defining context</a>, the latter as an <a href="#terms-audio-presentation-context">audio presentation context</a>.</p><p>When an <code>audio</code> element appears in an <a href="#terms-audio-defining-context">audio defining context</a>, it
-serves as a sharable definition of an <a href="#terms-audio-resource">audio resource</a> that may be referenced by other <code>audio</code> elements in the
-<a href="#terms-enclosing-document-instance">enclosing document instance</a>. In this case, the active time interval of the <code>audio</code> element
-is the same as the active time interval of its parent <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A sharable definition of an <a href="#terms-audio-resource">audio resource</a> specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute in order to be referenced
-by <code>audio</code> elements in an <a href="#terms-audio-presentation-context">audio presentation context</a>.</p></div><p>When an <code>audio</code> element appears in an <a href="#terms-audio-presentation-context">audio presentation context</a>, it
-serves as a non-sharable definition of an <a href="#terms-audio-resource">audio resource</a> that implies presentation (rendering) semantics, i.e., that it is intended to be played.
-In this case, the active time interval of the <code>audio</code> element is the same as the active time interval of its parent
-<a href="#terms-content-element">content element</a>.
-</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A non-sharable definition of an <a href="#terms-audio-resource">audio resource</a> may or may not specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute, but this
-identifier is not referenced by other <code>audio</code> elements, or, if it is, the reference is ignored.</p></div><p>The <code>audio</code> element accepts as its children
-zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by zero or more
-<a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><a id="elt-syntax-audio"></a><table class="syntax"><caption>XML Representation – Element Information Item: audio</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;audio
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-audio-format">&lt;audio-format&gt;</a>
-  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-audio">&lt;audio&gt;</a>
-  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute in TT Metadata namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-source">source</a>*
-&lt;/audio&gt;
-</pre></div>
-</td></tr></tbody></table><p>An <code>audio</code> element defines an <a href="#terms-audio-resource">audio resource</a> either (1) by referring to an <a href="#terms-external-data-resource">external data resource</a>
-or (2) defining or referring to an <a href="#terms-embedded-data-resource">embedded data resource</a>, where the <a href="#terms-data-resource">data resource</a>
-contains audio content.</p><p>If an <code>audio</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must not specify a
-child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element. Conversely,
-if an <code>audio</code> element does not specify a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must specify one or more
-child <a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><p>If an <code>audio</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute and its value does not refer to a fragment of the
-<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then it should specify a
-a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute, in which case the value of the
-<a href="#embedded-content-attribute-type"><code>type</code></a> attribute must correspond with the media (content) type
-of the referenced resource. Otherwise, a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must not be specified.</p><p>If a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute is not specified or is specified as a generic type, such as <code>application/octet-stream</code>,
-and additional format information is known about a referenced <a href="#terms-audio-resource">audio resource</a>, then a <a href="#embedded-content-attribute-format"><code>format</code></a> attribute should be specified as a hint to the
-content processor.</p><p>If an <code>audio</code> element includes a child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element, then
-the <a href="#embedded-content-attribute-format"><code>format</code></a> attribute of the <code>source</code> child, if specified, must adhere to the <a href="#embedded-content-value-audio-format">&lt;audio-format&gt;</a>
-value expression.</p><p>The use of the <code>audio</code> element is illustrated by the following example.</p><a id="embedded-content-vocabulary-audio-example-1"></a><table class="example"><caption>Example Fragment – External Audio Resource</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;audio src="http://example.com/audio/description.mp3" type="audio/mp3"/&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p></div><div class="div3">
-<h4><a id="embedded-content-vocabulary-chunk"></a>9.1.2 chunk</h4><p>The <code>chunk</code> element is used to represent a distinct chunk (fragment) of data.</p><p>A <code>chunk</code> element may appear as a child of a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element.</p><a id="elt-syntax-chunk"></a><table class="syntax"><caption>XML Representation – Element Information Item: chunk</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;chunk
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#embedded-content-attribute-encoding">encoding</a> = (base16|base32|base32hex|base64|base64url) : base64
-  length = <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA
-&lt;/chunk&gt;
-</pre></div>
-</td></tr></tbody></table><p>If an <a href="#embedded-content-attribute-encoding"><code>encoding</code></a> attribute is specified, then it must denote the actual encoding of the byte sequence represented by the
-<code>chunk</code> element. If no <a href="#embedded-content-attribute-encoding"><code>encoding</code></a> attribute is specified, then the encoding must be considered to be <code>base64</code>.</p><p>If a <code>length</code> attribute is specified, then it must denote the number of decoded bytes in the byte sequence represented by the
-<code>chunk</code> element. When decoding, if a specified length value does not match the number of decoded bytes, then the chunk and its container <code>data</code>
-element must return a zero length byte sequence.
-If no <code>length</code> attribute is specified, then the chunk is considered to have a length equal to the actual number of decoded bytes.</p><p>The use of chunked data is illustrated by the following example.</p><a id="embedded-content-vocabulary-chunk-example-1"></a><table class="example"><caption>Example Fragment – Chunked Data</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;data type="text/plain; charset=us-ascii" length="44"&gt;
-  &lt;chunk length="19"&gt;
-    VGhlIHF1aWNrIGJyb3duIGZveA==
-  &lt;/chunk&gt;
-  &lt;chunk length="25"&gt;
-    IGp1bXBzIG92ZXIgdGhlIGxhenkgZG9nLg==
-  &lt;/chunk&gt;
-&lt;/data&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p></div><div class="div3">
-<h4><a id="embedded-content-vocabulary-data"></a>9.1.3 data</h4><p>The <code>data</code> element functions as a generic container for or reference to arbitrary data.</p><p>A <code>data</code> element may appear in three contexts:
-(1) as a child of a <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element,
-referred to as a <a href="#terms-data-defining-context">data defining context</a>,
-(2) as a child of a <a href="#metadata-vocabulary-metadata"><code>metadata</code></a> element,
-referred to as a <a href="#terms-data-binding-context-for-metadata">data binding context for metadata</a>, or
-(3) as a child of a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element,
-referred to as a <a href="#terms-data-binding-context-for-source">data binding context for source</a>,
-and where these latter two contexts are referred to collectively as <a href="#terms-data-binding-context">data binding contexts</a>.</p><p>When a <code>data</code> element appears in a <a href="#terms-data-defining-context">data defining context</a>, it
-serves as a sharable definition of a data resource that may be referenced by the <a href="#embedded-content-attribute-src"><code>src</code></a> attribute of
-(1) another <code>data</code> element,
-(2) an <a href="#terms-embedded-content-element">embedded content element</a>, or
-(3) a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element.
-In this case, the contextualized active time interval of the <code>data</code> element is the intersection of
-the active time interval of its parent <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element and
-the active time interval of its referring element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A sharable definition of a data resource specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute in order to be referenced
-by a fragment identifier used in a <a href="#terms-data-binding-context">data binding context</a>.</p></div><p>When a <code>data</code> element appears in a <a href="#terms-data-binding-context">data binding context</a>, it
-serves as a non-sharable definition of a data resource that implies binding semantics, i.e., that it is intended to bound to (associated with) its immediate context
-of reference. In this case, the active time interval of the <code>data</code> element is the same as the active time interval of its closest ancestor timed element.
-</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A non-sharable definition of a data resource may or may not specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute, but this
-identifier is not referenced in other <a href="#terms-data-binding-context">data binding contexts</a>, or, if it is, has no binding semantics.</p></div><p>The <code>data</code> element accepts one of the following three content models:
-(1) one or more text nodes (i.e., <code>#PCDATA</code>),
-(2) zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by one or more
-<a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a> elements, or
-(3) zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by one or more
-<a href="#embedded-content-vocabulary-source"><code>source</code></a> elements, where
-the first is referred to as <a href="#terms-simple-data-embedding">simple data embedding</a>,
-the second as <a href="#terms-chunked-data-embedding">chunked data embedding</a>, and
-the third as <a href="#terms-sourced-data-embedding">sourced data embedding</a>.</p><p>When <a href="#terms-simple-data-embedding">simple data embedding</a> is used, the data resource is obtained by decoding the <code>#PCDATA</code> content.
-When <a href="#terms-chunked-data-embedding">chunked data embedding</a> is used, the data resource is obtained by concatenating the byte sequences obtained by decoding each
-child <a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a> element.
-When <a href="#terms-simple-data-embedding">sourced data embedding</a> is used, the data resource is obtained from the the first resolvable
-child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element. Furthermore,
-a child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element must not
-contain a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element, but may refer to a
-<a href="#embedded-content-vocabulary-data"><code>data</code></a> element in a <a href="#terms-data-defining-context">data defining context</a>.</p><a id="elt-syntax-data"></a><table class="syntax"><caption>XML Representation – Element Information Item: data</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;data
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#embedded-content-attribute-encoding">encoding</a> = (base16|base32|base32hex|base64|base64url) : <em>see prose below</em>
-  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-data-format">&lt;data-format&gt;</a>
-  length = <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>
-  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-data">&lt;data&gt;</a>
-  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a> : <em>see prose below</em>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA | (<a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-chunk">chunk</a>+) | (<a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-source">source</a>+)
-&lt;/data&gt;
-</pre></div>
-</td></tr></tbody></table><p>If simple data embedding is used, i.e., the content of the <code>data</code> element is one or more text nodes, then an
-<a href="#embedded-content-attribute-encoding"><code>encoding</code></a> attribute
-may be specified, and, if not specified, must be considered to be <code>base64</code>.
-If chunked or sourced data embedding is used, i.e., the content of the <code>data</code> element contains any child
-<a href="#embedded-content-vocabulary-chunk">chunk</a> or <a href="#embedded-content-vocabulary-source">source</a> element, then
-an <a href="#embedded-content-attribute-encoding"><code>encoding</code></a> attribute must not be specified, and, if specified, must be ignored
-for the purpose of content processing.</p><p>If a <code>length</code> attribute is specified, then it must denote the number of decoded bytes in the byte sequence represented by the
-<code>data</code> element. When decoding, if a specified length value does not match the number of decoded bytes, then a zero length byte sequence must be returned.
-If no <code>length</code> attribute is specified, then the data resource is considered to have a length equal to the actual number of decoded bytes.
-A <code>length</code> attribute must not be specified when using sourced data embedding.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The intention of the <code>length</code> attribute is to provide a means to perform a simple integrity check on decoded data. Note that this check does not guarantee
-data integrity during transport, i.e., the data could be modified without modifying the length.</p></div><p>If simple or chunked data embedding is used, a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must be specified,
-and must correspond with the media (content) type of the data resource. In these cases, if there is no defined type, the type <code>application/octet-stream</code>
-should be used. In the case of sourced data embedding, the media (content) type of the resolved <a href="#embedded-content-vocabulary-source">source</a> element
-is used as the type.</p><p>If a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute is not specified or resolved or is specified as a generic type,
-such as <code>application/octet-stream</code>, and additional format information is known about a referenced data resource,
-then a <a href="#embedded-content-attribute-format">format</a> attribute should be specified as a hint to the content processor.</p><p>The use of simple data embedding is illustrated by the following examples.</p><a id="embedded-content-vocabulary-data-example-1"></a><table class="example"><caption>Example Fragment – Simple Data Embedding in Data Defining Context</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;head&gt;
-  &lt;resources&gt;
-    &lt;data xml:id="sharedImageData" type="image/png" length="119"&gt;
-      iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
-      YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
-    &lt;/data&gt;
-    &lt;image xml:id="sharedImage"&gt;
-      &lt;source src="#sharedImageData"/&gt;
-    &lt;/image&gt;
-  &lt;/resources&gt;
-&lt;/head&gt;
-...
-&lt;body xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;div tts:backgroundImage="#sharedImage"/&gt;
-  &lt;div tts:backgroundImage="#sharedImage"/&gt;
-&lt;/body&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-data-example-2"></a><table class="example"><caption>Example Fragment – Simple Data Embedding in Data Binding Context for Metadata</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;div&gt;
-  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-    &lt;ttm:desc&gt;caption with metadata containing tunneled CEA-608 data&lt;/ttm:desc&gt;
-    &lt;data format="http://www.smpte-ra.org/schemas/2052-1/2013/smpte-tt#cea608"&gt;
-      gIAVLJQsnSAcIJ0sHCyAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICA
-      gICAgICAgICAgICAgICAgIAVIJQgE/QT9Jehl6FU5VTlc/Rz9CBDIENhcGFw9On06e9u725zgHOA
-      lNCU0Jehl6HEVMRU1iDWIMHjwePj5ePlc3NzcyDQINDy7/Lv6uXq5eP04/QsICwgV8dXx8LIwsit
-      zq3OQ8FDwc2AzYCUcJRwlyOXI6jyqPJ1bnVubulu6W5nbmcg9CD06W3pbeW65bogNCA0IG0gbelu
-      6W6uIK4gMbUxtSBzIHPl4+XjrimuKRUslCwVL5QvgIA=
-    &lt;/data&gt;
-  &lt;/metadata&gt;
-  &lt;p&gt;Test Captions&lt;br/&gt;DTV Access Project, WGHB-NCAM&lt;br/&gt;(running time: 4min. 15sec.)&lt;/p&gt;
-&lt;/div&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-data-example-3"></a><table class="example"><caption>Example Fragment – Simple Data Embedding in Data Binding Context for Source</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;div&gt;
-  &lt;image&gt;
-    &lt;source&gt;
-      &lt;data type="image/png" length="119"&gt;
-        iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
-        YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
-      &lt;/data&gt;
-    &lt;/source&gt;
-  &lt;/image&gt;
-&lt;/div&gt;
-</pre></div>
-</td></tr></tbody></table><p></p></div><div class="div3">
-<h4><a id="embedded-content-vocabulary-font"></a>9.1.4 font</h4><p>The <code>font</code> element is used to define an author supplied <a href="#terms-font-resource">font resource</a>.</p><p>A <code>font</code> element may appear as a child of a <a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element, referred to as a
-<a href="#terms-font-defining-context">font defining context</a>.</p><p>The <code>font</code> element accepts as its children
-zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by zero or more
-<a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><a id="elt-syntax-font"></a><table class="syntax"><caption>XML Representation – Element Information Item: font</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;font
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  family = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-font-format">&lt;font-format&gt;</a>
-  range = <a href="#embedded-content-value-unicode-range">&lt;unicode-range&gt;</a>
-  style = (normal|italic|oblique)
-  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-font">&lt;font&gt;</a>
-  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  weight = (normal|bold)
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-source">source</a>*
-&lt;/font&gt;
-</pre></div>
-</td></tr></tbody></table><p>A <code>font</code> element defines a <a href="#terms-font-resource">font resource</a> either (1) by referring to an <a href="#terms-external-data-resource">external data resource</a>
-or (2) defining or referring to an <a href="#terms-embedded-data-resource">embedded data resource</a>, where the <a href="#terms-data-resource">data resource</a>
-contains font content.</p><p>If a <code>font</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must not specify a
-child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element. Conversely,
-if a <code>font</code> element does not specify a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must specify one or more
-child <a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><p>If a <code>font</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute and its value does not refer to a fragment of the
-<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then it should specify a
-a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute, in which case the value of the
-<a href="#embedded-content-attribute-type"><code>type</code></a> attribute must correspond with the media (content) type
-of the referenced resource. Otherwise, a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must not be specified.</p><p>If a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute is not specified or is specified as a generic type, such as <code>application/octet-stream</code>,
-and additional format information is known about a referenced <a href="#terms-font-resource">font resource</a>, then a <a href="#embedded-content-attribute-format"><code>format</code></a> attribute should be specified as a hint to the
-content processor.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A font format hint might be useful to a content processor to avoid accessing a <a href="#terms-font-resource">font resource</a> it knows it cannot decode.</p></div><p>If a <code>font</code> element includes a child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element, then
-the <a href="#embedded-content-attribute-format"><code>format</code></a> attribute of the <code>source</code> child, if specified, must adhere to the <a href="#embedded-content-value-font-format">&lt;font-format&gt;</a>
-value expression.</p><p>If any of the <code>family</code>, <code>range</code>, <code>style</code>, or <code>weight</code> attributes are specified, then
-they override the family name, supported character ranges, style, and weight of the actual <a href="#terms-font-resource">font resource</a>. In particular,
-if the specified attribute value(s) differ from the value(s) of these font characteristics as encoded in the <a href="#terms-font-resource">font resource</a>, then
-the specified attribute value(s) are to be used instead of the font characteristics encoded in the <a href="#terms-font-resource">font resource</a>.</p><p>If any of the <code>family</code>, <code>range</code>, <code>style</code>, or <code>weight</code> attributes are not specified, then their values
-must be considered to be equal to the value(s) of the same named font characteristics encoded in the <a href="#terms-font-resource">font resource</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Authors are advised to use subset fonts wherever possible. A subset font is a syntactically valid <a href="#terms-font-resource">font resource</a> that
-removes unreferenced glyphs and unreferenced glyph metrics. In general, a subset font is tied to a specific document, since it may have been generated
-based on the actual character content of that document.</p></div><table border="1" class="ednote" summary="Editorial note: Font Loading Semantics"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Loading Semantics</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Specify font loading semantics, making as much use as possible (by reference) of material found at
-<a href="http://dev.w3.org/csswg/css-fonts/#font-face-loading">CSS Font Module Level 3, Font Loading Guidelines</a>.</td></tr></table><p>The use of the <code>font</code> element is illustrated by the following example.</p><a id="embedded-content-vocabulary-font-example-1"></a><table class="example"><caption>Example Fragment – Font</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;head&gt;
-  &lt;resources&gt;
-    &lt;data xml:id="lastResortFont" type="application/font-woff"&gt;
-      ... <em>base64 encoded data</em> ...
-    &lt;/data&gt;
-    &lt;font family="MyFont" range="u+20-7f,u+90-9f"&gt;
-      &lt;source src="http://example.com/fonts/myfont.otf" format="opentype"/&gt;
-      &lt;source src="#lastResortFont"/&gt;
-    &lt;/font&gt;
-  &lt;/resources&gt;
-&lt;/head&gt;
-...
-&lt;p tts:fontFamily="MyFont"&gt;use my font or last resort font&lt;/p&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p></div><div class="div3">
-<h4><a id="embedded-content-vocabulary-image"></a>9.1.5 image</h4><p>The <code>image</code> element is used to define an author supplied <a href="#terms-image-resource">image resource</a>.</p><p>An <code>image</code> element may appear in two contexts: (1) as a child of a <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element and
-(2) as a child of an element in the <a href="#element-vocab-group-block">Block.class</a> element group, namely, as a child of a
-<a href="#content-vocabulary-div"><code>div</code></a> or <a href="#content-vocabulary-p"><code>p</code></a> element, or
-as a child of a <a href="#content-vocabulary-span"><code>span</code></a> element. The former is referred to as an
-<a href="#terms-image-defining-context">image defining context</a>, the latter as an <a href="#terms-image-presentation-context">image presentation context</a>.</p><p>When an <code>image</code> element appears in an <a href="#terms-image-defining-context">image defining context</a>, it
-serves as a sharable definition of an <a href="#terms-image-resource">image resource</a> that may be referenced by another <code>image</code> element or by
-a <a href="#style-attribute-backgroundImage"><code>tts:backgroundImage</code></a> style attribute
-in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>. In this case, the active time interval of the <code>image</code> element
-is the same as the active time interval of its parent <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A sharable definition of an <a href="#terms-image-resource">image resource</a> specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute in order to be referenced
-by an <code>image</code> element or by a <a href="#style-attribute-backgroundImage"><code>tts:backgroundImage</code></a> style attribute
-in an <a href="#terms-image-presentation-context">image presentation context</a>.</p></div><p>When an <code>image</code> element appears in an <a href="#terms-image-presentation-context">image presentation context</a>, it
-serves as a non-sharable definition of an <a href="#terms-image-resource">image resource</a> that implies presentation (rendering) semantics.
-In this case, the active time interval of the <code>image</code> element is the same as the active time interval of its parent
-<a href="#terms-content-element">content element</a>.
-</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A non-sharable definition of an <a href="#terms-image-resource">image resource</a> may or may not specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute, but this
-identifier is not referenced by other <code>image</code> elements, or, if it is, the reference is ignored.</p></div><p>When an <code>image</code> element appears as a child of a <a href="#contentt-vocabulary-div"><code>div</code></a> element, then its presentation
-produces a block area in which the image is rendered; i.e., a block boundary is implied before and after the <code>image</code> element. In contrast,
-when an <code>image</code> element appears as a child of a <a href="#contentt-vocabulary-p"><code>p</code></a> or <a href="#contentt-vocabulary-span"><code>span</code></a>
-element, then its presentation produces an inline area in which the image is rendered; i.e., no block boundary is implied before and after the <code>image</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In <a href="#css2">[CSS2]</a>, these semantics would correspond to an <code>image</code> element being associated with a <code>display</code> style property with a
-value of <code>block</code> or <code>inline</code>, respectively.</p></div><p>The presentation of an <a href="#terms-image-resource">image resource</a> referenced by a
-<a href="#style-attribute-backgroundImage"><code>tts:backgroundImage</code></a> style attribute must not affect content layout.</p><p>The <code>image</code> element accepts as its children
-zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by zero or more
-<a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><a id="elt-syntax-image"></a><table class="syntax"><caption>XML Representation – Element Information Item: image</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;image
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-image-format">&lt;image-format&gt;</a>
-  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-image">&lt;image&gt;</a>
-  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xlink-arcrole">xlink:arcrole</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>+
-  <a href="#content-attribute-xlink-href">xlink:href</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-  <a href="#content-attribute-xlink-role">xlink:role</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>+
-  <a href="#content-attribute-xlink-show">xlink:show</a> = (<em>new</em>|<em>replace</em>|<em>embed</em>|<em>other</em>|<em>none</em>) : new
-  <a href="#content-attribute-xlink-title">xlink:title</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute in TT Metadata namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-source">source</a>*
-&lt;/image&gt;
-</pre></div>
-</td></tr></tbody></table><p>An <code>image</code> element defines an <a href="#terms-image-resource">image resource</a> either (1) by referring to an <a href="#terms-external-data-resource">external data resource</a>
-or (2) defining or referring to an <a href="#terms-embedded-data-resource">embedded data resource</a>, where the <a href="#terms-data-resource">data resource</a>
-contains image content.</p><p>If an <code>image</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must not specify a
-child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element. Conversely,
-if an <code>image</code> element does not specify a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must specify one or more
-child <a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><p>If an <code>image</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute and its value does not refer to a fragment of the
-<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then it should specify a
-a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute, in which case the value of the
-<a href="#embedded-content-attribute-type"><code>type</code></a> attribute must correspond with the media (content) type
-of the referenced resource. Otherwise, a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must not be specified.</p><p>If a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute is not specified or is specified as a generic type, such as <code>application/octet-stream</code>,
-and additional format information is known about a referenced <a href="#terms-image-resource">image resource</a>, then a <a href="#embedded-content-attribute-format"><code>format</code></a> attribute should be specified as a hint to the
-content processor.</p><p>If an <code>image</code> element includes a child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element, then
-the <a href="#embedded-content-attribute-format"><code>format</code></a> attribute of the <code>source</code> child, if specified, must adhere to the <a href="#embedded-content-value-image-format">&lt;image-format&gt;</a>
-value expression.</p><p>An <code>image</code> element may specify either (both)
-<a href="#style-attribute-width"><code>tts:width</code></a> or (and) 
-<a href="#style-attribute-height"><code>tts:height</code></a> style attributes in order to specify the presentation width or height of the image when
-intrinsic width or height information is not available or is intended to be overridden. If (either or both of) these attributes are specified on both an
-<code>image</code> element in an <a href="#terms-image-presentation-context">image presentation context</a> and on the
-<code>image</code> element in an <a href="#terms-image-defining-context">image defining context</a> to which the former refers, then
-these attributes specified on the former take precedence over those specified on the latter.</p><p>The linking attributes <code>xlink:*</code> may be used to link an <code>image</code> element with related content, using the
-specified location (<code>href</code>), roles, and title. The behavior of link activation is affected by the <code>xlink:show</code> attribute,
-the precise meaning of which is determined by the <a href="#terms-document-processing-context">document processing context</a>.</p><p>The use of the <code>image</code> element is illustrated by the following examples.</p><a id="embedded-content-vocabulary-image-example-1"></a><table class="example"><caption>Example Fragment – External Image Resources</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;div&gt;
-  &lt;p&gt;This division has a content image that appears as a block area after this paragraph.&lt;/p&gt;
-  &lt;image src="http://example.com/images/caption.png" type="image/png"/&gt;
-&lt;div&gt;
-...
-&lt;div tts:backgroundImage="http://example.com/images/background.png"&gt;
-  &lt;p&gt;This division has a background image that appears under this paragraph.&lt;/p&gt;
-&lt;div&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-image-example-2"></a><table class="example"><caption>Example Fragment – Sharable Embedded Image Resource</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;head&gt;
-  &lt;resources&gt;
-    &lt;data xml:id="caption" type="image/png" length="119"&gt;
-      iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
-      YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
-    &lt;/data&gt;
-  &lt;/resources&gt;
-&lt;/head&gt;
-&lt;body&gt;
-  &lt;div&gt;
-    &lt;p&gt;
-      &lt;image&gt;
-        &lt;source src="#caption"/&gt;
-      &lt;/image&gt;
-    &lt;p&gt;
-    ...
-    &lt;p&gt;
-      &lt;image&gt;
-        &lt;source src="#caption"/&gt;
-      &lt;/image&gt;
-    &lt;p&gt;
-  &lt;/div&gt;
-&lt;/body&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-image-example-3"></a><table class="example"><caption>Example Fragment – External Image Resource with Non-Sharable Image Fallback</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;div&gt;
-  &lt;image&gt;
-    &lt;source src="http://example.com/images/caption.png" type="image/png"/&gt;
-    &lt;source&gt;
-      &lt;data type="image/png" length="119"&gt;
-        iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
-        YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
-      &lt;/data&gt;
-    &lt;/source&gt;
-  &lt;/image&gt;
-&lt;/div&gt;
-</pre></div>
-</td></tr></tbody></table><p></p></div><div class="div3">
-<h4><a id="embedded-content-vocabulary-resources"></a>9.1.6 resources</h4><p>The <code>resources</code> element is a container element used to group
-definitions of embedded content, including metadata that applies to this embedded content.</p><p>The <code>resources</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more elements in the
-<a href="#element-vocab-group-data"><code>Data.class</code></a>,
-<a href="#element-vocab-group-data"><code>Embedded.class</code></a>, or
-<a href="#element-vocab-group-data"><code>Font.class</code></a> element groups.</p><a id="elt-syntax-resources"></a><table class="syntax"><caption>XML Representation – Element Information Item: resources</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;resources
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, (<a href="#element-vocab-group-data">Data.class</a>|<a href="#element-vocab-group-embedded">Embedded.class</a>|<a href="#element-vocab-group-font">Font.class</a>)*
-&lt;/resources&gt;
-</pre></div>
-</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
-<code>resources</code> element, the implied time interval of this element is
-defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div><div class="div3">
-<h4><a id="embedded-content-vocabulary-source"></a>9.1.7 source</h4><p>The <code>source</code> element is used to specify the source of an <a href="#terms-embedded-content-resource">embedded content resource</a>.</p><p>The <code>source</code> element accepts as its children
-zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by zero or one
-<a href="#embedded-content-vocabulary-data"><code>data</code></a> element.</p><p>If a <code>source</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must not specify a
-child <a href="#embedded-content-vocabulary-data"><code>data</code></a> element, in which case it is referred to as
-an <a href="#terms-external-source">external source</a> if the <a href="#embedded-content-attribute-src"><code>src</code></a> attribute refers to an external resource, or
-a <a href="#terms-non-nested-embedded-source">non-nested embedded source</a>
-if the <a href="#embedded-content-attribute-src"><code>src</code></a> attribute refers to an embedded resource
-in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p><p>If a <code>source</code> element does not specify a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must specify a
-child <a href="#embedded-content-vocabulary-data"><code>data</code></a> element, in which case it is referred to as
-a <a href="#terms-nested-embedded-source">nested embedded source</a>.</p><p>A <code>source</code> element must not have an ancestor <code>source</code> element.</p><a id="elt-syntax-source"></a><table class="syntax"><caption>XML Representation – Element Information Item: source</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;source
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-data-format">&lt;data-format&gt;</a>
-  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-data">&lt;data&gt;</a>
-  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-data">data</a>?
-&lt;/source&gt;
-</pre></div>
-</td></tr></tbody></table><p>If a <a href="#embedded-content-attribute-format"><code>format</code></a> attribute is specified, then it provides additional hint information about the format (i.e., formal syntax) of the
-embedded content. Such information may be useful in cases where no standard media (content) type label has been defined. Depending on the
-context of use of a <code>source</code> element, the values of this attribute may be further constrained.</p><p>If a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute is specified and its value refers to a fragment of the <a href="#terms-enclosing-document-instance">enclosing document instance</a>,
-then there must be a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element child of a <a href="#document-structure-vocabulary-resources"><code>resources</code></a>
-element which is identified by that fragment, i.e., has an <code>xml:id</code> attribute the value of which matches the fragment identifier.</p><p>If a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute is specified and its value does not refer to a fragment of the
-<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then
-a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute should be specified, in which case it must correspond with the media (content) type
-of the referenced resource.</p><p>If a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute is specified and its value does refer to a fragment of the
-<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then
-a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must not be specified; rather, the content type of the embedded resource is determined by
-the value of the <a href="#embedded-content-attribute-type"><code>type</code></a> attribute on the referenced or embedded
-<a href="#embedded-content-vocabulary-data"><code>data</code></a> element.</p><p>The use of the <code>source</code> element is illustrated by the following examples.</p><a id="embedded-content-vocabulary-source-example-1"></a><table class="example"><caption>Example Fragment – External Source</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;image&gt;
-  &lt;source src="http://example.com/images/caption.png" type="image/png"/&gt;
-&lt;/image&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-source-example-2"></a><table class="example"><caption>Example Fragment – Non-Nested Embedded Source</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;data xml:id="caption" type="image/png" length="119"&gt;
-  iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
-  YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
-&lt;/data&gt;
-...
-&lt;image&gt;
-  &lt;source src="#caption"/&gt;
-&lt;/image&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-source-example-3"></a><table class="example"><caption>Example Fragment – Nested Embedded Source</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;image&gt;
-  &lt;source&gt;
-    &lt;data type="image/png" length="119"&gt;
-      iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
-      YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
-    &lt;/data&gt;
-  &lt;/source&gt;
-&lt;/image&gt;
-...
-</pre></div>
-</td></tr></tbody></table></div></div><div class="div2">
-<h3><a id="embedded-content-attribute-vocabulary"></a>9.2 Embedded Content Attribute Vocabulary</h3><p>This section defines the following attributes for use with certain <a href="#terms-embedded-content-element">embedded content elements</a>
-and <a href="#terms-embedded-data-element">data elements</a>:</p><ul><li><p><a href="#embedded-content-attribute-encoding"><b>9.2.1 encoding</b></a></p></li><li><p><a href="#embedded-content-attribute-format"><b>9.2.2 format</b></a></p></li><li><p><a href="#embedded-content-attribute-src"><b>9.2.3 src</b></a></p></li><li><p><a href="#embedded-content-attribute-type"><b>9.2.4 type</b></a></p></li></ul><div class="div3">
-<h4><a id="embedded-content-attribute-encoding"></a>9.2.1 encoding</h4><p>The <code>encoding</code> attribute is used to specify the encoding format of data.</p><p>The <code>encoding</code> attribute may be specified by an instance of the following
-element types:</p><ul><li><p><a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><code>data</code></a></p></li></ul><p>If specified, the value of an <code>encoding</code> attribute must take one of the following values as defined by
-<a href="#data-encodings">[Data Encodings]</a>:</p><ul><li><p><code>base16</code></p></li><li><p><code>base32</code></p></li><li><p><code>base32hex</code></p></li><li><p><code>base64</code></p></li><li><p><code>base64url</code></p></li></ul><p>If not specified, then <code>base64</code> semantics apply.</p></div><div class="div3">
-<h4><a id="embedded-content-attribute-format"></a>9.2.2 format</h4><p>The <code>format</code> attribute is used to specify hints about the media (content) format of
-an embedded content resource beyond media (content) type information
-provided by a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <code>format</code> attribute is useful in the absence of a registered media (content) type,
-e.g., when no media (content) type is available or a generic type is used, such as
-<code>application/octet-stream</code>.</p></div><p>The <code>format</code> attribute may be specified by an instance of the following
-element types:</p><ul><li><p><a href="#embedded-content-vocabulary-audio"><code>audio</code></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><code>data</code></a></p></li><li><p><a href="#embedded-content-vocabulary-font"><code>font</code></a></p></li><li><p><a href="#embedded-content-vocabulary-image"><code>image</code></a></p></li><li><p><a href="#embedded-content-vocabulary-source"><code>source</code></a></p></li></ul><p>The value of a <code>format</code> attribute must adhere to a
-<a href="#embedded-content-value-data-format">&lt;data-format&gt;</a> expression.</p><p>Depending on the context of use, additional constraints may apply.</p></div><div class="div3">
-<h4><a id="embedded-content-attribute-src"></a>9.2.3 src</h4><p>The <code>src</code> attribute is used to specify the location or an identifier that maps to the location of data resource.</p><p>The <code>src</code> attribute may be specified by an instance of the following
-element types:</p><ul><li><p><a href="#embedded-content-vocabulary-audio"><code>audio</code></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><code>data</code></a></p></li><li><p><a href="#embedded-content-vocabulary-font"><code>font</code></a></p></li><li><p><a href="#embedded-content-vocabulary-image"><code>image</code></a></p></li><li><p><a href="#embedded-content-vocabulary-source"><code>source</code></a></p></li></ul><p>If specified, the value of a <code>src</code> attribute must adhere to the value syntax of the
-<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>, §3.2.17.</p><p>Depending on the context of use, additional constraints may apply.</p></div><div class="div3">
-<h4><a id="embedded-content-attribute-type"></a>9.2.4 type</h4><p>The <code>type</code> attribute is used to specify the media (content) type of data resource, and may express additional
-parameters that characterize the data.</p><p>The <code>type</code> attribute may be specified by an instance of the following
-element types:</p><ul><li><p><a href="#embedded-content-vocabulary-audio"><code>audio</code></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><code>data</code></a></p></li><li><p><a href="#embedded-content-vocabulary-font"><code>font</code></a></p></li><li><p><a href="#embedded-content-vocabulary-image"><code>image</code></a></p></li></ul><p>If specified, the value of a <code>type</code> attribute must adhere to the value syntax of the <code>Content-Type</code>
-MIME header defined by <a href="#mime">[MIME]</a>, §5.1.</p><p>If not specified, then the media (content) type is unknown or deliberately unspecified.</p><p>When decoding a data resource for which a <code>type</code> attribute is specified, then content processing
-must respect the specified type whether it is correct or not. That is, if a <code>type</code> attribute mis-specifies the
-type of a data resource, then content processing must not attempt to override that type by performing content
-sniffing.</p></div></div><div class="div2">
-<h3><a id="embedded-content-value-expressions"></a>9.3 Embedded Content Value Expressions</h3><p>Embedded content elements as well as certain style property values make use of the following expressions:</p><ul><li><p><a href="#embedded-content-value-audio"><b>9.3.1 &lt;audio&gt;</b></a></p></li><li><p><a href="#embedded-content-value-audio-format"><b>9.3.2 &lt;audio-format&gt;</b></a></p></li><li><p><a href="#embedded-content-value-data"><b>9.3.3 &lt;data&gt;</b></a></p></li><li><p><a href="#embedded-content-value-data-format"><b>9.3.4 &lt;data-format&gt;</b></a></p></li><li><p><a href="#embedded-content-value-font"><b>9.3.5 &lt;font&gt;</b></a></p></li><li><p><a href="#embedded-content-value-font-format"><b>9.3.6 &lt;font-format&gt;</b></a></p></li><li><p><a href="#embedded-content-value-image"><b>9.3.7 &lt;image&gt;</b></a></p></li><li><p><a href="#embedded-content-value-image-format"><b>9.3.8 &lt;image-format&gt;</b></a></p></li><li><p><a href="#embedded-content-value-unicode-range"><b>9.3.9 &lt;unicode-range&gt;</b></a></p></li></ul><p>In the syntax representations defined in this section, no
-linear whitespace (LWSP) is implied or permitted between tokens
-unless explicitly specified.</p><div class="div3">
-<h4><a id="embedded-content-value-audio"></a>9.3.1 &lt;audio&gt;</h4><p>An &lt;audio&gt; value expression is used to specify an <a href="#terms-audio-resource">audio resource</a> by reference.</p><a id="audio-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;audio&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;audio&gt;
-  : <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-</pre></div>
-</td></tr></tbody></table><p>If an &lt;audio&gt; value expression takes the form of a <a href="#terms-fragment-identifier">fragment identifier</a>,
-then that fragment identifier must reference an <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element that is a child of a
-<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p></div><div class="div3">
-<h4><a id="embedded-content-value-audio-format"></a>9.3.2 &lt;audio-format&gt;</h4><p>An &lt;audio-format&gt; expression is used to specify the format of a <a href="#terms-audio-resource">audio resource</a>. Additional format information is useful in the case
-of <a href="#terms-audio-resource">audio resources</a> that lack a registered media (content) type.</p><a id="audio-format-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;audio-format&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;audio-format&gt;
-  : <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
-  | <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-</pre></div>
-</td></tr></tbody></table><p>If a format expression takes the form of an <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
-then it must express an absolute URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not standardize the set of format tokens for use with audio content. Authors are encouraged to
-use tokens in common use, or absent that, to add a prefix <code>"x-"</code> to form a private use token.</p></div></div><div class="div3">
-<h4><a id="embedded-content-value-data"></a>9.3.3 &lt;data&gt;</h4><p>A &lt;data&gt; value expression is used to specify a data resource by reference.</p><a id="data-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;data&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;data&gt;
-  : <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-</pre></div>
-</td></tr></tbody></table><p>If a &lt;data&gt; value expression takes the form of a <a href="#terms-fragment-identifier">fragment identifier</a>,
-then that fragment identifier must reference an <a href="#embedded-content-vocabulary-data"><code>data</code></a> element that is a child of a
-<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p></div><div class="div3">
-<h4><a id="embedded-content-value-data-format"></a>9.3.4 &lt;data-format&gt;</h4><p>A &lt;data-format&gt; expression is used to specify the format of a data resource. Additional format information is useful in the case
-of data resources that lack a registered media (content) type.</p><a id="data-format-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;data-format&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;data-format&gt;
-  : <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
-  | <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-</pre></div>
-</td></tr></tbody></table><p>If a format expression takes the form of an <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
-then it must express an absolute URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not standardize the set of format tokens for use with data content. Authors are encouraged to
-use tokens in common use, or absent that, to add a prefix <code>"x-"</code> to form a private use token.</p></div></div><div class="div3">
-<h4><a id="embedded-content-value-font"></a>9.3.5 &lt;font&gt;</h4><p>An &lt;font&gt; expression is used to specify a <a href="#terms-font-resource">font resource</a> by reference.</p><a id="font-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;font&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;font&gt;
-  : <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-</pre></div>
-</td></tr></tbody></table><p>If a &lt;font&gt; expression takes the form of a <a href="#terms-fragment-identifier">fragment identifier</a>,
-then that fragment identifier must reference a <a href="#embedded-content-vocabulary-font"><code>font</code></a> element that is a child of a
-<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p></div><div class="div3">
-<h4><a id="embedded-content-value-font-format"></a>9.3.6 &lt;font-format&gt;</h4><p>A &lt;font-format&gt; expression is used to specify the format of a <a href="#terms-font-resource">font resource</a>. Additional format information is useful in the case
-of <a href="#terms-font-resource">font resources</a> due that lack a registered media (content) type.</p><a id="font-format-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;font-format&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;font-format&gt;
-  : eot                                     // embedded opentype
-  | otf                                     // opentype
-  | ttf                                     // truetype
-  | woff                                    // web open font format
-  | <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
-  | <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-</pre></div>
-</td></tr></tbody></table><p>If a format expression takes the form of an <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
-then it must express an absolute URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification standardizes a limited set of format tokens for use with font content. In case none of
-these tokens are appropriate, authors are encouraged to use tokens in common use, or absent that, to add a
-prefix <code>"x-"</code> to form a private use token.</p></div></div><div class="div3">
-<h4><a id="embedded-content-value-image"></a>9.3.7 &lt;image&gt;</h4><p>An &lt;image&gt; expression is used to specify an <a href="#terms-image-resource">image resource</a> by reference.</p><a id="image-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;image&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;image&gt;
-  : <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-</pre></div>
-</td></tr></tbody></table><p>If an &lt;image&gt; expression takes the form of a <a href="#terms-fragment-identifier">fragment identifier</a>,
-then that fragment identifier must reference an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element that is a child of a
-<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p></div><div class="div3">
-<h4><a id="embedded-content-value-image-format"></a>9.3.8 &lt;image-format&gt;</h4><p>An &lt;image-format&gt; expression is used to specify the format of a <a href="#terms-image-resource">image resource</a>. Additional format information is useful in the case
-of <a href="#terms-image-resource">image resources</a> that lack a registered media (content) type.</p><a id="image-format-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;image-format&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;image-format&gt;
-  : <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
-  | <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
-</pre></div>
-</td></tr></tbody></table><p>If a format expression takes the form of a <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
-then it must express an absolute URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not standardize the set of format tokens for use with image content. Authors are encouraged to
-use tokens in common use, or absent that, to add a prefix <code>"x-"</code> to form a private use token.</p></div></div><div class="div3">
-<h4><a id="embedded-content-value-unicode-range"></a>9.3.9 &lt;unicode-range&gt;</h4><p>A &lt;unicode-range&gt; expression is used to specify a collection of Unicode codepoints by enumerating singleton codepoints or ranges of codepoints.</p><a id="unicode-range-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;unicode-range&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;unicode-range&gt;
-  : range ("," range)*
-
-range
-  : codepoint
-  | codepoint "-" codepoint
-
-codepoint
-  : ("U"|"u") "+" hexdigit-or-wildcard{1,6}
-
-hexdigit-or-wildcard
-  : <a href="#style-value-hexDigit">&lt;hexDigit&gt;</a>
-  | "?"
-</pre></div>
-</td></tr></tbody></table><p>No LWSP is permitted within a <code>codepoint</code> sub-expression.</p></div></div></div><div class="div1">
-<h2><a id="styling"></a>10 Styling</h2><p>This section specifies the <em>styling</em> matter of the core
-vocabulary catalog, where
-styling is to be understood as a separable layer of information that applies to
-content and that denotes authorial intentions about the presentation of
-that content.</p><p>Styling attributes are included in TTML to enable authorial intent of presentation
-to be included within a self-contained document. This section describes
-the semantics of style presentation in terms of a standard processing
-model. TTML Processors are not required to present <a href="#terms-document-instance">document instances</a> in any particular way; 
-but an implementation of this model by a TTML <a href="#terms-presentation-processor">presentation processor</a>
-that provides externally observable results that are consistent with this model is
-likely to lead to a user experience that closely resembles the experience intended by
-the documents' authors.</p><p>The semantics of TTML style presentation are described in terms of the model 
-in <a href="#xsl11">[XSL 1.1]</a>. The effects of the attributes in this section 
-are intended to be compatible with the layout and formatting model of XSL; however, Presentation agents
-may use any technology to satisfy the authorial intent of the document. In particular 
-since <a href="#css2">[CSS2]</a> is a subset of this model, a CSS processor may be used 
-for the features that the models have in common.</p><p>No normative use of an
-<code>&lt;?xml-stylesheet ... ?&gt;</code> processing instruction is defined
-by this specification.</p><div class="div2">
-<h3><a id="styling-element-vocabulary"></a>10.1 Styling Element Vocabulary</h3><p>The following elements specify the structure and principal styling aspects of a
-<a href="#terms-document-instance">document instance</a>:</p><ul><li><p><a href="#styling-vocabulary-initial"><b>10.1.1 initial</b></a></p></li><li><p><a href="#styling-vocabulary-style"><b>10.1.2 style</b></a></p></li><li><p><a href="#styling-vocabulary-styling"><b>10.1.3 styling</b></a></p></li></ul><div class="div3">
-<h4><a id="styling-vocabulary-initial"></a>10.1.1 initial</h4><p>The <code>initial</code> element is used to modify the initial value of one or more style properties, i.e, to specify use of different value(s) than
-the specification defined initial value(s).</p><p>The <code>initial</code> element accepts as its children zero or more <code>metadata</code> elements.</p><a id="elt-syntax-initial"></a><table class="syntax"><caption>XML Representation – Element Information Item: initial</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;initial
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
-&lt;/initial&gt;
-</pre></div>
-</td></tr></tbody></table><p>The <code>initial</code> element is illustrated by the following example, wherein
-the initial value of the <code>tts:color</code> property is defined to be <code>yellow</code>.</p><a id="style-vocabulary-initial-example-1"></a><table class="example"><caption>Example Fragment – <code>initial</code></caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;head&gt;
-  &lt;styling&gt;
-    <span class="strong">&lt;initial tts:color="yellow"/&gt;</span>
-  &lt;styling&gt;
-&lt;head&gt;
-...
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="styling-vocabulary-style"></a>10.1.2 style</h4><p>The <code>style</code> element is used to define
-a set of style specifications expressed as a
-specified style set in accordance with
-<a href="#semantics-style-resolution-processing-sss"><b>10.4.4.2 Specified Style Set Processing</b></a>.</p><p>The <code>style</code> element accepts as its children zero or more <code>metadata</code> elements.</p><a id="elt-syntax-style"></a><table class="syntax"><caption>XML Representation – Element Information Item: style</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;style
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
-&lt;/style&gt;
-</pre></div>
-</td></tr></tbody></table><p>If a <code>style</code> element appears as a descendant of a
-<code>region</code> element, then the <code>style</code> element must be
-ignored for the purpose of computing referential styles as defined by
-<a href="#semantics-style-association-referential"><b>10.4.1.2 Referential Styling</b></a> and <a href="#semantics-style-association-chained-referential"><b>10.4.1.3 Chained Referential Styling</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>That is to say, when referential styling is used by an element to
-refer to a <code>style</code> element, then the referenced <code>style</code>
-element must appear as a descendant of the <code>styling</code> element, and
-not in any other context.</p></div></div><div class="div3">
-<h4><a id="styling-vocabulary-styling"></a>10.1.3 styling</h4><p>The <code>styling</code> element is a container element used to group
-styling matter, including metadata that applies to styling matter.</p><p>The <code>styling</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more <code>initial</code> elements,
-followed by zero or more <code>style</code> elements.</p><a id="elt-syntax-styling"></a><table class="syntax"><caption>XML Representation – Element Information Item: styling</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;styling
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#styling-vocabulary-initial">initial</a>*, <a href="#styling-vocabulary-style">style</a>*
-&lt;/styling&gt;
-</pre></div>
-</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
-<code>styling</code> element, the implied time interval of this element is
-defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div></div><div class="div2">
-<h3><a id="styling-attribute-vocabulary"></a>10.2 Styling Attribute Vocabulary</h3><p>This section defines the <a href="#style-attribute-style"><b>10.2.1 style</b></a> attribute used
-with certain animation elements, <a href="#terms-content-element">content elements</a>, certain layout elements, and style definition elements.</p><p>In addition, this section specifies the following attributes in the TT Style Namespace
-for use with style definition elements, certain layout elements, and <a href="#terms-content-element">content elements</a>
-that support inline style specifications:</p><ul><li><p><a href="#style-attribute-backgroundColor"><b>10.2.2 tts:backgroundColor</b></a></p></li><li><p><a href="#style-attribute-backgroundImage"><b>10.2.3 tts:backgroundImage</b></a></p></li><li><p><a href="#style-attribute-backgroundPosition"><b>10.2.4 tts:backgroundPosition</b></a></p></li><li><p><a href="#style-attribute-backgroundRepeat"><b>10.2.5 tts:backgroundRepeat</b></a></p></li><li><p><a href="#style-attribute-border"><b>10.2.6 tts:border</b></a></p></li><li><p><a href="#style-attribute-color"><b>10.2.7 tts:color</b></a></p></li><li><p><a href="#style-attribute-direction"><b>10.2.8 tts:direction</b></a></p></li><li><p><a href="#style-attribute-display"><b>10.2.9 tts:display</b></a></p></li><li><p><a href="#style-attribute-displayAlign"><b>10.2.10 tts:displayAlign</b></a></p></li><li><p><a href="#style-attribute-extent"><b>10.2.11 tts:extent</b></a></p></li><li><p><a href="#style-attribute-fontFamily"><b>10.2.12 tts:fontFamily</b></a></p></li><li><p><a href="#style-attribute-fontKerning"><b>10.2.13 tts:fontKerning</b></a></p></li><li><p><a href="#style-attribute-fontShear"><b>10.2.15 tts:fontShear</b></a></p></li><li><p><a href="#style-attribute-fontSelectionStrategy"><b>10.2.14 tts:fontSelectionStrategy</b></a></p></li><li><p><a href="#style-attribute-fontSize"><b>10.2.16 tts:fontSize</b></a></p></li><li><p><a href="#style-attribute-fontStyle"><b>10.2.17 tts:fontStyle</b></a></p></li><li><p><a href="#style-attribute-fontVariantPosition"><b>10.2.18 tts:fontVariantPosition</b></a></p></li><li><p><a href="#style-attribute-fontWeight"><b>10.2.19 tts:fontWeight</b></a></p></li><li><p><a href="#style-attribute-height"><b>10.2.20 tts:height</b></a></p></li><li><p><a href="#style-attribute-letterSpacing"><b>10.2.21 tts:letterSpacing</b></a></p></li><li><p><a href="#style-attribute-lineHeight"><b>10.2.22 tts:lineHeight</b></a></p></li><li><p><a href="#style-attribute-opacity"><b>10.2.23 tts:opacity</b></a></p></li><li><p><a href="#style-attribute-origin"><b>10.2.24 tts:origin</b></a></p></li><li><p><a href="#style-attribute-overflow"><b>10.2.25 tts:overflow</b></a></p></li><li><p><a href="#style-attribute-padding"><b>10.2.26 tts:padding</b></a></p></li><li><p><a href="#style-attribute-position"><b>10.2.27 tts:position</b></a></p></li><li><p><a href="#style-attribute-ruby"><b>10.2.28 tts:ruby</b></a></p></li><li><p><a href="#style-attribute-rubyAlign"><b>10.2.29 tts:rubyAlign</b></a></p></li><li><p><a href="#style-attribute-rubyOffset"><b>10.2.30 tts:rubyOffset</b></a></p></li><li><p><a href="#style-attribute-rubyPosition"><b>10.2.31 tts:rubyPosition</b></a></p></li><li><p><a href="#style-attribute-showBackground"><b>10.2.32 tts:showBackground</b></a></p></li><li><p><a href="#style-attribute-textAlign"><b>10.2.33 tts:textAlign</b></a></p></li><li><p><a href="#style-attribute-textCombine"><b>10.2.34 tts:textCombine</b></a></p></li><li><p><a href="#style-attribute-textDecoration"><b>10.2.35 tts:textDecoration</b></a></p></li><li><p><a href="#style-attribute-textEmphasis"><b>10.2.36 tts:textEmphasis</b></a></p></li><li><p><a href="#style-attribute-textOrientation"><b>10.2.37 tts:textOrientation</b></a></p></li><li><p><a href="#style-attribute-textOutline"><b>10.2.38 tts:textOutline</b></a></p></li><li><p><a href="#style-attribute-textShadow"><b>10.2.39 tts:textShadow</b></a></p></li><li><p><a href="#style-attribute-unicodeBidi"><b>10.2.40 tts:unicodeBidi</b></a></p></li><li><p><a href="#style-attribute-visibility"><b>10.2.41 tts:visibility</b></a></p></li><li><p><a href="#style-attribute-width"><b>10.2.42 tts:width</b></a></p></li><li><p><a href="#style-attribute-wrapOption"><b>10.2.43 tts:wrapOption</b></a></p></li><li><p><a href="#style-attribute-writingMode"><b>10.2.44 tts:writingMode</b></a></p></li><li><p><a href="#style-attribute-zIndex"><b>10.2.45 tts:zIndex</b></a></p></li></ul><table border="1" class="ednote" summary="Editorial note: Additional Border Styling Attributes"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Additional Border Styling Attributes</b></td><td align="right" valign="top">2013-08-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Consider adding support for <code>tts:borderColor</code>, <code>tts:borderStyle</code>, and <code>tts:borderWidth</code>
-in order to provide a means to independently express styling of the four different borders (top, right, bottom, left). As currently specified, i.e., with only the
-<code>tts:border</code> attribute, one can only express the four borders using the same color, style, and width.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Background Clip, Origin, Size"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Background Clip, Origin, Size</b></td><td align="right" valign="top">2014-11-27</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Consider adding support for <code>tts:backgroundClip</code>,
-<code>tts:backgroundOrigin</code>, and
-<code>tts:backgroundSize</code>.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Additional Width/Height Related Attributes"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Additional Width/Height Related Attributes</b></td><td align="right" valign="top">2014-11-30</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Given the addition of <code>tts:width</code> and <code>tts:height</code>, consider also adding
-<code>tts:minWidth</code>, <code>tts:maxWidth</code>, <code>tts:minHeight</code>, and <code>tts:minHeight</code>.</td></tr></table><p>Unless explicitly permitted by an element type definition, an attribute in the TT Style Namespace should not be specified on an element
-unless it either applies to that element or denotes an inheritable style property. If it does not apply to that element
-and does not denote an inheritable style property, then it must be ignored for the purpose of non-validation processing.
-In the case of validation processing, such usage should be reported as a warning, or, if strict validation is performed,
-as an error.</p><p>Unless explicitly stated otherwise, linear white-space (LWSP) must
-appear between adjacent non-terminal components of a value of a TT
-Style property value unless some other delimiter is permitted and used.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification makes use of <em>lowerCamelCased</em> local
-names for style attributes that
-are based upon like-named properties defined by <a href="#xsl11">[XSL 1.1]</a>.
-This convention is likewise extended to token values of such
-properties.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>An inheritable style property may be expressed as a specified attribute on the
-root <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element or on a
-<a href="#terms-content-element">content element</a> type
-independently of whether the property applies to that
-element type. This capability permits the expression of an inheritable
-style property on ancestor elements to which the property
-does not apply.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Due to the general syntax of this specification (and the schemas it references) with respect
-to how style attributes are specified, particularly for the purpose of supporting inheritance,
-it is possible for an author to inadvertently specify a non-inheritable style attribute on
-an element that applies neither to that element or any of its descendants while still remaining
-conformant from a content validity perspective. Content authors may wish to make use of TTML
-content verification tools that detect and warn about such usage.</p></div><div class="div3">
-<h4><a id="style-attribute-style"></a>10.2.1 style</h4><p>The <code>style</code> attribute is used by referential style association
-to reference one or more <code>style</code> elements each of which define a style (property) set.</p><p>The <code>style</code> attribute may be specified by an instance of the following
-element types:</p><ul><li><p><a href="#animation-vocabulary-animate"><code>animate</code></a></p></li><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#animation-vocabulary-set"><code>set</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li><li><p><a href="#styling-vocabulary-style"><code>style</code></a></p></li></ul><p>If specified, the value of a <code>style</code> attribute must
-adhere to the <code>IDREFS</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§ 3.3.10, and, furthermore, each IDREF must reference a <code>style</code> element
-which has a <code>styling</code> element as an ancestor.</p><p>If the same IDREF, <em>ID<sub>1</sub></em>, appears more than one time in the value of a <code>style</code>
-attribute, then there should be an intervening IDREF, <em>ID<sub>2</sub></em>, where 
-<em>ID<sub>2</sub></em> is not equal to <em>ID<sub>1</sub></em>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This constraint is intended to discourage the use of redundant referential styling while still
-allowing the same style to be referenced multiple times in order to potentially override prior
-referenced styles, e.g., when an intervening, distinct style is referenced in the IDREFS list.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>See the specific element type definitions that permit use of the
-<code>style</code> attribute, as well as <a href="#semantics-style-association-referential"><b>10.4.1.2 Referential Styling</b></a> and <a href="#semantics-style-association-chained-referential"><b>10.4.1.3 Chained Referential Styling</b></a>, for
-further information on its semantics.</p></div></div><div class="div3">
-<h4><a id="style-attribute-backgroundColor"></a>10.2.2 tts:backgroundColor</h4><p>The <code>tts:backgroundColor</code> attribute is used to specify a style property that
-defines the background color of a region or an area generated by content flowed into a region.</p><div class="issue"><p class="prefix"><a id="issue-302"></a><b>Issue (issue-302):</b></p><p class="prefix"><b>Line Area Background Height</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/302">http://www.w3.org/AudioVideo/TT/tracker/issues/302</a></p><p>Fix definition of block progression dimension of background area of a line area. Neither XSL-FO nor CSS are sufficiently precise.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-backgroundColor"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-color">&lt;color&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>transparent</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>The <code>tts:backgroundColor</code> style is illustrated by the following example.</p><a id="style-attribute-backgroundColor-example-1"></a><table class="example"><caption>Example Fragment – Background Color</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="306px 114px"/&gt;
-  &lt;style <span class="strong">tts:backgroundColor="red"</span>/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:padding="3px 40px"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1" <span class="strong">tts:backgroundColor="purple"</span> tts:textAlign="center"&gt;
-  Twinkle, twinkle, little bat!&lt;br/&gt;
-  How &lt;span <span class="strong">tts:backgroundColor="green"</span>&gt;I wonder&lt;/span&gt; where you're at!
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-backgroundColor-example-1-images"></a><table class="example-images"><caption>Example Rendition – Background Color</caption><tbody><tr><td><img src="images/backgroundColor.png" alt="TTML backgroundColor style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-that defined by <a href="#xsl11">[XSL 1.1]</a>, § 7.8.2.</p></div></div><div class="div3">
-<h4><a id="style-attribute-backgroundImage"></a>10.2.3 tts:backgroundImage</h4><p>The <code>tts:backgroundImage</code> attribute is used to specify a style property that
-designates a background <a href="#non-content-image">non-content image</a> to be rendered as
-the background image of a region or an area generated by content flowed into a region.</p><p>A <code>tts:backgroundImage</code> attribute should not make reference to a <a href="#content-image">content image</a>
-used to represent actual content, such as a raster image rendering of a caption. Rather, the use of <code>tts:backgroundImage</code>
-should be limited to styling the background of an element where the content is represented by other means. If it is necessary
-to represent content using a raster image, then it should be expressed by means of an <a href="#embedded-content-vocabulary-image"><code>image</code></a>
-element in a block or inline context.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-backgroundImage"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#embedded-content-value-image">&lt;image&gt;</a> |
-none
-</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>An <a href="#embedded-content-value-image">&lt;image&gt;</a> expression used with this style property may directly reference an external <a href="#terms-image-resource">image resource</a>;
-however, authors should refrain from doing so, and instead, constrain their usage to only refer to <a href="#embedded-content-vocabulary-image"><code>image</code></a>
-children of a <a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Referring indirectly to an image by means of an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element makes it possible to
-specify an image as an <a href="#terms-embedded-data-resource">embedded data resource</a>, and specify
-additional information about the image, such as its content type, etc. Furthermore, by exploiting the use of multiple
-<a href="#embedded-content-vocabulary-source"><code>source</code></a> children in an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element,
-it becomes possible to specify resolution specific images and fallback <a href="#terms-image-resource">image resources</a>.</p></div><p>The <code>tts:backgroundImage</code> style is illustrated by the following example.</p><a id="style-attribute-backgroundImage-example-1"></a><table class="example"><caption>Example Fragment – Background Image using Embedded Image Resource</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;head&gt;
-  &lt;resources&gt;
-    &lt;image xml:id="embeddedImage"&gt;
-      &lt;source&gt;
-        &lt;data type="image/png" length="119"&gt;
-          iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
-          YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
-        &lt;/data&gt;
-      &lt;/source&gt;
-    &lt;/image&gt;
-  &lt;/resources&gt;
-&lt;/head&gt;
-...
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="306px 114px"/&gt;
-  &lt;style tts:backgroundImage="red"/&gt;
-  &lt;style <span class="strong">tts:backgroundImage="#embeddedImage"</span>/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:padding="3px 40px"/&gt;
-&lt;/region&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Background Image Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Background Image Example Image</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of backgroundImage example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-that defined by <a href="#xsl11">[XSL 1.1]</a>, § 7.8.3.</p></div></div><div class="div3">
-<h4><a id="style-attribute-backgroundPosition"></a>10.2.4 tts:backgroundPosition</h4><p>The <code>tts:backgroundPosition</code> attribute is used to specify a style property that
-defines whether and how a background image is positioned in a region or an area generated by content flowed into a region.</p><p>This attribute may be specified by any element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-backgroundPosition"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-position">&lt;position&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>0% 0%</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>A percentage value component for a horizontal position offset is relative to the width of the
-positioning area minus the width of the background image.
-A percentage value component for a vertical position offset is relative to the height of the
-positioning area minus the height of the background image.
-The positioning area corresponds with the padding rectangle (padding box) of each area generated
-by applicable element.</p><p>The <code>tts:backgroundPosition</code> style is illustrated by the following example.</p><a id="style-attribute-backgroundPosition-example-1"></a><table class="example"><caption>Example Fragment – Background Position</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="306px 114px"/&gt;
-  &lt;style tts:backgroundImage="#embeddedImage"/&gt;
-  &lt;style <span class="strong">tts:backgroundPosition="center"</span>/&gt;
-&lt;/region&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Background Position Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Background Position Example Image</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of backgroundPosition example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-that defined by <a href="#css2">[CSS2]</a>, § 14.2.</p></div></div><div class="div3">
-<h4><a id="style-attribute-backgroundRepeat"></a>10.2.5 tts:backgroundRepeat</h4><p>The <code>tts:backgroundRepeat</code> attribute is used to specify a style property that
-defines whether and how a background image is repeated (tiled) into a region or an area generated by content flowed into a region.</p><p>This attribute may be specified by any element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-backgroundRepeat"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>repeat</code> |
-<code>repeatX</code> |
-<code>repeatY</code> |
-<code>noRepeat</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>repeat</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>The <code>tts:backgroundRepeat</code> style is illustrated by the following example.</p><a id="style-attribute-backgroundRepeat-example-1"></a><table class="example"><caption>Example Fragment – Background Repeat</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="306px 114px"/&gt;
-  &lt;style tts:backgroundImage="#embeddedImage"/&gt;
-  &lt;style <span class="strong">tts:backgroundRepeat="repeatX"</span>/&gt;
-&lt;/region&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Background Repeat Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Background Repeat Example Image</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of backgroundRepeat example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-that defined by <a href="#xsl11">[XSL 1.1]</a>, § 7.8.4.</p></div></div><div class="div3">
-<h4><a id="style-attribute-border"></a>10.2.6 tts:border</h4><p>The <code>tts:border</code> attribute is used to specify a style property that
-defines the border of a region or an area generated by content flowed into a region.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-border"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-[
-<a href="#style-value-borderWidth">&lt;borderWidth&gt;</a> ||
-<a href="#style-value-borderStyle">&lt;borderStyle&gt;</a> ||
-<a href="#style-value-borderColor">&lt;borderColor&gt;</a>
-]
-</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous (color and width only)</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If no border width is specified in the value of the <code>tts:border</code> property,
-then the border width must be interpreted as if a width of
-<code>medium</code> were specified.</p><p>If a computed value of the border width associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the one-dimensional Euclidean distance between
-the computed border width and the supported border width is minimized on a per-edge basis. If there are multiple closest supported values equally distant from
-the computed value for a given edge, then the value least distant from 0, i.e., the least border width, is used.</p></div><p>If no border style is specified in the value of the <code>tts:border</code> property,
-then the border style must be interpreted as if a style of
-<code>none</code> were specified.</p><p>If a computed value of the border style associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>solid</code>.</p><p>If no border color is specified in the value of the <code>tts:border</code> property,
-then the border color must be interpreted as if a color equal
-to the computed value of the element's <code>tts:color</code> style property were specified.</p><p>The <code>tts:border</code> style is illustrated by the following example.</p><a id="style-attribute-border-example-1"></a><table class="example"><caption>Example Fragment – Border</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="306px 114px"/&gt;
-  &lt;style <span class="strong">tts:border="2px solid red"</span>/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:padding="3px 40px"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1" <span class="strong">tts:border="4px solid green"</span> tts:textAlign="center"&gt;
-  Twinkle, twinkle, little bat!&lt;br/&gt;
-  How &lt;span <span class="strong">tts:border="8px solid blue"</span>&gt;I wonder&lt;/span&gt; where you're at!
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Border Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Border Example Image</b></td><td align="right" valign="top">2013-08-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of border example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-that defined by <a href="#xsl11">[XSL 1.1]</a>, § 7.31.3.</p></div></div><div class="div3">
-<h4><a id="style-attribute-color"></a>10.2.7 tts:color</h4><p>The <code>tts:color</code> attribute is used to specify a style property that
-defines the foreground color of marks associated with an area generated by content flowed into a region.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-color"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-color">&lt;color&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td>see prose</td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>The initial value of the <code>tts:color</code> property
-is considered to be implementation dependent. In the absence of
-end-user preference information, a conformant <a href="#terms-presentation-processor">presentation processor</a>
-should use an initial value that is highly contrastive to the
-background color of the <a href="#terms-root-container-region">root container region</a>.</p><p>The <code>tts:color</code> style is illustrated by the following example.</p><a id="style-attribute-color-example-1"></a><table class="example"><caption>Example Fragment – Color</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style <span class="strong">tts:color="white"</span>/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  In spring, when woods are &lt;span <span class="strong">tts:color="green"</span>&gt;getting green&lt;/span&gt;,&lt;br/&gt;
-  I'll try and tell you what I mean.
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-color-example-1-images"></a><table class="example-images"><caption>Example Rendition – Color</caption><tbody><tr><td><img src="images/color.png" alt="TTML color style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.18.1.</p></div></div><div class="div3">
-<h4><a id="style-attribute-direction"></a>10.2.8 tts:direction</h4><p>The <code>tts:direction</code> attribute is used to specify a style property that
-defines the directionality of an embedding or override according to
-the Unicode bidirectional algorithm.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-direction"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>ltr</code> |
-<code>rtl</code>
-</td></tr><tr><td><em>Initial:</em></td><td>
-<code>ltr</code>
-</td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>ltr</code>.</p><p>The <code>tts:direction</code> style is illustrated by the following example.</p><a id="style-attribute-direction-example-1"></a><table class="example"><caption>Example Fragment – Direction</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="265px 84px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  Little birds are playing&lt;br/&gt;
-  Bagpipes on the shore,&lt;br/&gt;
-  &lt;span tts:unicodeBidi="bidiOverride" <span class="strong">tts:direction="rtl"</span>&gt;where the tourists snore.&lt;/span&gt;
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-direction-example-1-images"></a><table class="example-images"><caption>Example Rendition – Direction</caption><tbody><tr><td>
-<img src="images/direction.png" alt="TTML direction style property">
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.29.1.</p></div></div><div class="div3">
-<h4><a id="style-attribute-display"></a>10.2.9 tts:display</h4><p>The <code>tts:display</code> attribute is used to specify a style property that
-defines whether an element is a candidate for layout and composition
-in a region.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-display"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>auto</code> |
-<code>none</code>
-</td></tr><tr><td><em>Initial:</em></td><td>
-<code>auto</code>
-</td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If the value of this attribute is <code>auto</code>,
-then the affected element is a candidate for region layout and
-presentation; however, if the value is <code>none</code>, then the
-affected element and its descendants must be considered ineligible for region
-layout and presentation.</p><p>The <code>tts:display</code> style is illustrated by the following example.</p><a id="style-attribute-display-example-1"></a><table class="example"><caption>Example Fragment – Display</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="369px 119px"
-            tts:backgroundColor="black"
-            tts:color="white"
-            tts:displayAlign="before"
-            tts:textAlign="start"/&gt;
-&lt;/region&gt;
-...
-&lt;div region="r1"&gt;
-  &lt;p dur="5s"&gt;
-    [[[
-    &lt;span <span class="strong">tts:display="none"</span>&gt;
-      &lt;set begin="1s" dur="1s" <span class="strong">tts:display="auto"</span>/&gt;
-      Beautiful soup,
-    &lt;/span&gt;
-    &lt;span <span class="strong">tts:display="none"</span>&gt;
-      &lt;set begin="2s" dur="1s" <span class="strong">tts:display="auto"</span>/&gt;
-      so rich and green,
-    &lt;/span&gt;
-    &lt;span <span class="strong">tts:display="none"</span>&gt;
-      &lt;set begin="3s" dur="1s" <span class="strong">tts:display="auto"</span>/&gt;
-      waiting in a hot tureen!
-    &lt;/span&gt;
-    ]]]
-  &lt;/p&gt;
-&lt;/div&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-display-example-1-images"></a><table class="example-images"><caption>Example Rendition – Display</caption><tbody><tr><td>
-<img src="images/display_0.png" alt="TTML display style property - [0,1)">
-</td></tr><tr><td>
-<img src="images/display_1.png" alt="TTML display style property - [1,2)">
-</td></tr><tr><td>
-<img src="images/display_2.png" alt="TTML display style property - [2,3)">
-</td></tr><tr><td>
-<img src="images/display_3.png" alt="TTML display style property - [3,4)">
-</td></tr><tr><td>
-<img src="images/display_4.png" alt="TTML display style property - [4,5)">
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#css2">[CSS2]</a>, § 9.2.4.</p></div></div><div class="div3">
-<h4><a id="style-attribute-displayAlign"></a>10.2.10 tts:displayAlign</h4><p>The <code>tts:displayAlign</code> attribute is used to specify a style property that
-defines the alignment of block areas in the block progression direction.</p><table border="1" class="ednote" summary="Editorial note: Justification in Block Progression Dimension"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Justification in Block Progression Dimension</b></td><td align="right" valign="top">2015-01-14</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add <code>justify</code> value to support justification in block progression dimension.</td></tr></table><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-displayAlign"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>before</code> |
-<code>center</code> |
-<code>after</code>
-</td></tr><tr><td><em>Initial:</em></td><td>
-<code>before</code>
-</td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#layout-vocabulary-region"><code>region</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>before</code>.</p><p>The <code>tts:displayAlign</code> style is illustrated by the following example.</p><a id="style-attribute-displayAlign-example-1"></a><table class="example"><caption>Example Fragment – Display Align</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="128px 66px" tts:origin="0px 0px"
-       tts:backgroundColor="black" tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:displayAlign="before"</span>/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:extent="192px 66px" tts:origin="128px 66px"/&gt;
-       tts:backgroundColor="green" tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:displayAlign="after"</span>/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r3"&gt;
-  &lt;style tts:extent="128px 66px"/&gt; style tts:origin="0px 132px"
-       tts:backgroundColor="black" tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:displayAlign="before"</span>/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r4"&gt;
-  &lt;style tts:extent="192px 66px" tts:origin="128px 198px"/&gt;
-       tts:backgroundColor="green" tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:displayAlign="after"</span>/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-...
-&lt;div&gt;
-  &lt;p region="r1"&gt;I sent a message to the fish:&lt;/p&gt;
-  &lt;p region="r2"&gt;I told them&lt;br/&gt; "This is what I wish."&lt;/p&gt;
-  &lt;p region="r3"&gt;The little fishes of the sea,&lt;/p&gt;
-  &lt;p region="r4"&gt;They sent an&lt;br/&gt; answer back to me.&lt;/p&gt;
-&lt;/div&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-displayAlign-example-1-images"></a><table class="example-images"><caption>Example Rendition – Display Align</caption><tbody><tr><td><img src="images/displayAlign.png" alt="TTML displayAlign style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.14.4.</p></div></div><div class="div3">
-<h4><a id="style-attribute-extent"></a>10.2.11 tts:extent</h4><p>The <code>tts:extent</code> attribute is used to specify the
-<em>width</em> and <em>height</em> of a region area. It may also be used to specify the extent of
-the <a href="#terms-root-container-region">root container region</a>, which has the effect of defining
-the <a href="#terms-document-coordinate-space">document coordinate space</a>.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-extent"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>auto</code> |
-<code>contain</code> |
-<code>cover</code> |
-<a href="#style-value-measure">&lt;measure&gt;</a> <a href="#style-value-measure">&lt;measure&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-tt"><code>tt</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>relative to width and height of <a href="#terms-root-container-region">root container region</a></td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute consists of two <a href="#style-value-measure">&lt;measure&gt;</a>
-specifications, then they must be interpreted as <em>width</em>
-and <em>height</em>, where the first specification is the
-<em>width</em>, and the second specification is the <em>height</em>.</p><p>The <a href="#style-value-measure">&lt;measure&gt;</a> value(s) used to express extent must be non-negative.</p><p>If the value of this attribute is <code>auto</code>, then the computed value
-of the style property must be considered to be the same as the extent of the <a href="#terms-root-container-region">root container region</a>.</p><table border="1" class="ednote" summary="Editorial note: Semantics of contain and cover"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Semantics of contain and cover</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define semantics of new <code>contain</code> and <code>cover</code> values.</td></tr></table><p>The extent of the <a href="#terms-root-container-region">root container region</a> is determined either by a
-<code>tts:extent</code> specified on the <code>tt</code> element, if
-present, or as described by <a href="#document-structure-vocabulary-tt"><b>8.1.1 tt</b></a> if not present.
-If <code>tts:extent</code> is specified on the <code>tt</code> element, then
-the width and height must be expressed in terms of two <a href="#style-value-length">&lt;length&gt;</a> specifications,
-and these specifications must be expressed as non-percentage, definite lengths using pixel units.</p><p>If a <code>tts:extent</code> attribute is specified on a <code>div</code> or <code>p</code> element, then that specification must be considered to be
-equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>div</code> or <code>p</code> element, where the
-extent of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
-value of this attribute.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
-the computed extent and the supported extent is minimized. If there are multiple closest supported values equally distant from
-the computed value, then the value most distant from [0,0], i.e., of greatest extent, is used.</p><p>This rule for resolving <em>closest supported value</em> makes use of the nearest larger rather than nearest smaller supported distance.
-The rationale for this difference in treatment is
-that use of a larger extent ensures that the affected content will be contained in the region area without causing region overflow,
-while use of a smaller extent makes region overflow more likely.</p></div><p>The <code>tts:extent</code> style is illustrated by the following example.</p><a id="style-attribute-extent-example-1"></a><table class="example"><caption>Example Fragment – Extent</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style <span class="strong">tts:extent="330px 122px"</span>/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  'Tis the voice of the Lobster:&lt;br/&gt;
-  I heard him declare,&lt;br/&gt;
-  "You have baked me too brown,&lt;br/&gt;
-  I must sugar my hair."
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-extent-example-1-images"></a><table class="example-images"><caption>Example Rendition – Extent</caption><tbody><tr><td><img src="images/extent.png" alt="TTML extent style property"></td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-attribute-fontFamily"></a>10.2.12 tts:fontFamily</h4><p>The <code>tts:fontFamily</code> attribute is used to specify a style property that
-defines the font family from which glyphs are selected for glyph areas generated
-by content flowed into a region.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontFamily"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-(<a href="#style-value-familyName">&lt;familyName&gt;</a> | <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a>)
-(<code>","</code>
-&nbsp;(<a href="#style-value-familyName">&lt;familyName&gt;</a> | <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a>))*
-</td></tr><tr><td><em>Initial:</em></td><td><code>default</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The initial value, <code>default</code>, is a generic font family name, and is
-further described in <a href="#style-value-genericFamilyName"><b>10.3.11 &lt;genericFamilyName&gt;</b></a> below.</p></div><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If a computed value of the property associated with this attribute is not supported, then a
-<a href="#terms-presentation-processor">presentation processor</a> must attempt to map the computed font family
-to a supported font family that has similar typographic
-characteristics, or, in the absence of such a mapping, it must
-use the value <code>default</code>.</p><p>The <code>tts:fontFamily</code> style is illustrated by the following example.</p><a id="style-attribute-fontFamily-example-1"></a><table class="example"><caption>Example Fragment – Font Family</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="474px 146px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-  &lt;style <span class="strong">tts:fontFamily="proportionalSansSerif"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;div region="r1"&gt;
-  &lt;p&gt;
-    "The time has come," the Walrus said,&lt;br/&gt;
-    "to talk of many things:
-  &lt;/p&gt;
-  &lt;p tts:textAlign="end" <span class="strong">tts:fontFamily="monospaceSerif"</span>&gt;
-    Of shoes, and ships, and sealing wax,&lt;br/&gt;
-    Of cabbages and kings,
-  &lt;/p&gt;
-  &lt;p&gt;
-    And why the sea is boiling hot,&lt;br/&gt;
-    and whether pigs have wings."
-  &lt;/p&gt;
-&lt;/div&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-fontFamily-example-1-images"></a><table class="example-images"><caption>Example Rendition – Font Family</caption><tbody><tr><td><img src="images/fontFamily.png" alt="TTML fontFamily style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.9.2.</p></div></div><div class="div3">
-<h4><a id="style-attribute-fontKerning"></a>10.2.13 tts:fontKerning</h4><p>The <code>tts:fontKerning</code> attribute is used to specify a style property that
-determines whether font kerning is applied when positioning glyph areas.</p><p>This attribute may be specified by any element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontKerning"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>none</code> |
-<code>normal</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If the value of this attribute is <code>normal</code>, then kerning should be applied if kerning data is available.
-If the value of this attribute is <code>none</code>, then kerning should not be applied whether or not kerning data is available.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><p>The <code>tts:fontKerning</code> style is illustrated by the following
-example.</p><table border="1" class="ednote" summary="Editorial note: Font Kerning Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Kerning Example</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:fontKerning.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#css3-fonts">[CSS Fonts]</a>,
-§ 6.3.</p></div></div><div class="div3">
-<h4><a id="style-attribute-fontSelectionStrategy"></a>10.2.14 tts:fontSelectionStrategy</h4><table border="1" class="ednote" summary="Editorial note: Define tts:fontSelectionStrategy"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Define tts:fontSelectionStrategy</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define <code>tts:fontSelectionStrategy</code> style property based on
-the XSL 1.1 <a href="http://www.w3.org/TR/xsl/#font-selection-strategy">font-selection-strategy</a> and
-recent <a href="http://lists.w3.org/Archives/Public/public-tt/2014Nov/0051.html">TTWG ML thread</a>.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Font Selection"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Selection</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Specify font selection semantics, including how multiple author defined <a href="#terms-font-resource">font resources</a> combine
-with (local) platform defined <a href="#terms-font-resource">font resources</a> to obtain an ordered list of <a href="#terms-font-resource">font resources</a> for performing
-character to glyph mapping.</td></tr></table></div><div class="div3">
-<h4><a id="style-attribute-fontShear"></a>10.2.15 tts:fontShear</h4><p>The <code>tts:fontShear</code> attribute is used to specify a style property that
-determines whether and how a shear transformation is applied to glyph areas.</p><p>This attribute may be specified by any element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontShear"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-length">&lt;percentage&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>0%</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute is <code>0%</code>, then no shear transformation is applied; if the value is <code>100%</code>, then a 2D shear transformation
-of 90 degrees is applied in the axis associated with the inline progression direction; if the value is <code>-100%</code>, then a shear transformation
-of -90 degrees is applied. If the absolute value of the specified percentage is greater than 100%, then it must be interpreted as if 100% were specified with
-the appropriate sign.</p><p>If the inline progression direction corresponds to the X axis, then the 2D shear transformation is described by the following matrix:</p><div class="exampleInner"><pre>
-| 1 <em>a</em> 0 |
-| 0 1 0 |
-| 0 0 1 |
-</pre></div><p>where <em>a</em> is equal to the tangent of the shear angle.</p><p>If the inline progression direction corresponds to the Y axis, then the 2D shear transformation is described by the following matrix:</p><div class="exampleInner"><pre>
-| 1 0 0 |
-| <em>a</em> 1 0 |
-| 0 0 1 |
-</pre></div><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>The <code>tts:fontShear</code> style is illustrated by the following
-example.</p><table border="1" class="ednote" summary="Editorial note: Font Shear Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Shear Example</b></td><td align="right" valign="top">2015-01-07</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:fontShear.</td></tr></table></div><div class="div3">
-<h4><a id="style-attribute-fontSize"></a>10.2.16 tts:fontSize</h4><p>The <code>tts:fontSize</code> attribute is used to specify a style property
-that defines the font size for glyphs that are selected for glyph areas
-generated by content flowed into a region.</p><p>This attribute may be specified by any element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontSize"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a>?
-</td></tr><tr><td><em>Initial:</em></td><td><code>1c</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>if not <a href="#content-vocabulary-span"><code>region</code></a> element,
-then relative to parent element's font size; otherwise, relative to the
-<a href="#terms-computed-cell-size">computed cell size</a></td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If a single <a href="#style-value-length">&lt;length&gt;</a> value is specified, then this length applies
-equally to horizontal and vertical scaling of a glyph's EM square; if two
-<a href="#style-value-length">&lt;length&gt;</a> values are specified, then the first expresses the horizontal
-scaling and the second expresses vertical scaling.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Use of independent horizontal and vertical font sizes is expected to be used
-with cell based units in order to denote fonts that are two rows in height and
-one column in width.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>A glyph's EM square is conventionally defined as the EM square of the font that contains the glyph. That is,
-glyphs do not have an EM square that is distinct from their font's EM square.</p></div><p>If horizontal and vertical sizes are expressed independently, then the
-units of the <a href="#style-value-length">&lt;length&gt;</a> values must be the same.</p><p>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used to express font size must be non-negative.</p><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
-the computed font size and the supported font size is minimized. If there are multiple closest supported values equally distant from
-the computed value, then the value most distant from 0 (single length specification) or [0,0] (two length specifications) is used,
-i.e., the largest font size, is used.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The expression <code>1c</code> means one cell, where <code>'c'</code> expresses
-the <em>cell</em> length unit as defined by <a href="#style-value-length"><b>10.3.14 &lt;length&gt;</b></a>.
-When a single &lt;length&gt; is expressed using cell units, then it refers to the height of
-the <a href="#terms-computed-cell-size">computed cell size</a>.
-When two &lt;length&gt; values are expressed using cell units, then the first refers to the width of
-the <a href="#terms-computed-cell-size">computed cell size</a>, and the second refers to the height of the
-<a href="#terms-computed-cell-size">computed cell size</a>.</p></div><p>The <code>tts:fontSize</code> style is illustrated by the following example.</p><a id="style-attribute-fontSize-example-1"></a><table class="example"><caption>Example Fragment – Font Size</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="299px 97px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style <span class="strong">tts:fontSize="18px"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  Then fill up the glasses&lt;br/&gt;
-  with treacle and ink,&lt;br/&gt;
-  Or anything else&lt;br/&gt;
-  that is &lt;span <span class="strong">tts:fontSize="24px"</span>&gt;pleasant&lt;/span&gt; to drink.
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-fontSize-example-1-images"></a><table class="example-images"><caption>Example Rendition – Font Size</caption><tbody><tr><td><img src="images/fontSize.png" alt="TTML fontSize style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.9.4. The addition of a second length component to permit specifying font
-width and height independently is an extension introduced by TTML.</p></div></div><div class="div3">
-<h4><a id="style-attribute-fontStyle"></a>10.2.17 tts:fontStyle</h4><p>The <code>tts:fontStyle</code> attribute is used to specify a style property that
-defines the font style to apply to glyphs that are selected for glyph areas generated
-by content flowed into a region, where the mapping from font
-style value to specific font face or style parameterization is not determined
-by this specification.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontStyle"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>normal</code> |
-<code>italic</code> |
-<code>oblique</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>Use of the value <code>oblique</code>
-denotes a shear transformation (at an unspecified
-angle) in the inline progression dimension.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><p>The <code>tts:fontStyle</code> style is illustrated by the following example.</p><a id="style-attribute-fontStyle-example-1"></a><table class="example"><caption>Example Fragment – Font Style</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="331px 84px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  In autumn, when the leaves are brown,&lt;br/&gt;
-  Take pen and ink, and &lt;span <span class="strong">tts:fontStyle="italic"</span>&gt;write it down.&lt;/span&gt;
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-fontStyle-example-1-images"></a><table class="example-images"><caption>Example Rendition – Font Style</caption><tbody><tr><td><img src="images/fontStyle.png" alt="TTML fontStyle style property"></td></tr></tbody></table><p></p><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.9.7.</p></div></div><div class="div3">
-<h4><a id="style-attribute-fontVariantPosition"></a>10.2.18 tts:fontVariantPosition</h4><p>The <code>tts:fontVariantPosition</code> attribute is used to enable the selection
-of typographic subscript and superscript glyphs.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontVariantPosition"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>normal</code> |
-<code>sub</code> |
-<code>super</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><table border="1" class="ednote" summary="Editorial note: Font Position Variant Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Position Variant Example</b></td><td align="right" valign="top">2014-09-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add example source and rendering of tts:fontVariantPosition.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#css3-fonts">[CSS Fonts]</a>,
-§ 6.5.</p></div></div><div class="div3">
-<h4><a id="style-attribute-fontWeight"></a>10.2.19 tts:fontWeight</h4><p>The <code>tts:fontWeight</code> attribute is used to specify a style property
-that defines the font weight to apply to glyphs that are selected for glyph
-areas generated by content flowed into a region, where the mapping from font
-weight value to specific font face or weight parameterization is not determined
-by this specification.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontWeight"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>normal</code> |
-<code>bold</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><p>The <code>tts:fontWeight</code> style is illustrated by the following example.</p><a id="style-attribute-fontWeight-example-1"></a><table class="example"><caption>Example Fragment – Font Weight</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="376px 95px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  They told me you had been to her,&lt;br/&gt;
-  &lt;span <span class="strong">tts:fontWeight="bold"</span>&gt;and mentioned me to him:&lt;/span&gt;&lt;br/&gt;
-  She gave me a good character&lt;br/&gt;
-  &lt;span <span class="strong">tts:fontWeight="bold"</span>&gt;but said I could not swim.&lt;/span&gt;
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-fontWeight-example-1-images"></a><table class="example-images"><caption>Example Rendition – Font Weight</caption><tbody><tr><td><img src="images/fontWeight.png" alt="TTML fontWeight style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.9.9.</p></div></div><div class="div3">
-<h4><a id="style-attribute-height"></a>10.2.20 tts:height</h4><p>The <code>tts:height</code> attribute is used to specify the
-<em>height</em> of an area generated by content flowed into a region.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The term <em>height</em> is interpreted in a writing mode relative manner
-such that <em>height</em> always corresponds to a measure in the block
-progression direction. Therefore, in horizontal writing modes, <em>height</em> expresses a vertical measure,
-while, in vertical writing mode, <em>height</em> expresses a horizontal measure,
-where horizontal and vertical are always interpreted in an absolute sense.</p></div><p>If a <code>tts:height</code> attribute is specified on a <a href="#content-vocabulary-span"><code>span</code></a> element,
-then that <a href="#content-vocabulary-span"><code>span</code></a> element must be processed using
-<a href="#terms-inline-block-display">inline block display</a> semantics for the purpose of presentation processing.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-height"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-measure">&lt;measure&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>,
-<a href="#embedded-content-vocabulary-image"><code>image</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If a <a href="#style-value-measure">&lt;measure&gt;</a> is expressed as a <a href="#style-value-length">&lt;length&gt;</a> value, then it must be non-negative.</p><p>The <code>tts:height</code> style is illustrated by the following example.</p><table border="1" class="ednote" summary="Editorial note: Height Percentage"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Height Percentage</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Specify resolution of percentage value.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Height Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Height Example</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:height.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.15.6, and <a href="#css3-box">[CSS Box Model]</a>, § 9</p></div></div><div class="div3">
-<h4><a id="style-attribute-letterSpacing"></a>10.2.21 tts:letterSpacing</h4><p>The <code>tts:letterSpacing</code> attribute is used to specify a style property that
-increases or decreases the nominal distance between glyph areas.</p><p>Letter spacing has no affect at the beginning or ending of a line area, and must not
-be applied to zero-width glyphs. Furthermore, letter spacing must not cause normally connected glyphs,
-e.g., as used in cursive scripts or with cursive fonts, to become disconnected.</p><p>Letter spacing is applied independently from kerning and justification. Depending upon the font(s) in use,
-the script(s) being presented, and the capabilities of a presentation processor, either or both kerning and
-justification may be applied in addition to letter spacing.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-letterSpacing"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>normal</code> |
-<a href="#style-value-length">&lt;length&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>The value <code>normal</code> corresponds to specifying a <a href="#style-value-length">&lt;length&gt;</a> value of zero (0),
-i.e., neither expand nor compress adjacent glyph spacing.</p><p>If a <a href="#style-value-length">&lt;length&gt;</a> value is expressed as a positive scalar,
-then the spaces between adjacent glyphs are expanded by an additional amount equal to that scalar value.
-If expressed as a negative scalar,
-then the spaces between adjacent glyphs are compressed by an additional amount equal to that scalar value, possibly resulting
-in overlapping glyph areas, up to a maximum amount that results an effective advance of zero (0).</p><p>If a computed value of the letter spacing associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the one-dimensional Euclidean distance between
-the computed letter spacing and the supported letter spacing is minimized. If there are multiple closest supported values equally distant from
-the computed value for a given edge, then the value least distant from 0 is used.</p></div><p>The <code>tts:letterSpacing</code> style is illustrated by the following
-example.</p><table border="1" class="ednote" summary="Editorial note: Letter Spacing Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Letter Spacing Example</b></td><td align="right" valign="top">2014-11-30</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:letterSpacing.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#css3-text">[CSS Text]</a>,
-§ 8.2.</p></div></div><div class="div3">
-<h4><a id="style-attribute-lineHeight"></a>10.2.22 tts:lineHeight</h4><p>The <code>tts:lineHeight</code> attribute is used to specify a style property that
-defines the inter-baseline separation between line areas generated by content flowed into a region.</p><div class="issue"><p class="prefix"><a id="issue-284"></a><b>Issue (issue-284):</b></p><p class="prefix"><b>Normal Line Height Multiplier</b></p><p><b>Source</b>: <a href="https://www.w3.org/AudioVideo/TT/tracker/issues/284">https://www.w3.org/AudioVideo/TT/tracker/issues/284</a></p><p>Re-visit choice of 120% versus 125% for multiplier used in interpreting <code>normal</code> line height.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-lineHeight"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>normal</code> |
-<a href="#style-value-length">&lt;length&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>relative to this element's font size</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute is <code>normal</code>, then the
-computed value of this style property is determined as follows:</p><ol class="enumar"><li><p>
-Let <em>P</em> be the <code>p</code> element to which this style property applies.
-</p></li><li><p>
-Let <em>FF</em> be the computed value of the <code>tts:fontFamily</code> style property that applies to <em>P</em>.
-</p></li><li><p>
-Let <em>FS</em> be the computed value of the <code>tts:fontSize</code> style property that applies to <em>P</em>.
-</p></li><li><p>
-Let <em>F0</em> be the first font obtained when sequentially mapping each font family in <em>FF</em> to a set of available fonts,
-where this set of available fonts is constrained as needed to satisfy the computed values of the <code>tts:fontStyle</code> and <code>tts:fontWeight</code>
-style properties that apply to <em>P</em>.
-</p></li><li><p>
-If <em>F0</em> is associated with font metrics that specify altitude <em>A</em>, descent <em>D</em>, and line gap <em>G</em>,
-then set <em>LH</em> to the sum of scaled(<em>A</em>), scaled(<em>D</em>), and scaled(<em>G</em>),
-where scaled(<em>X</em>) denotes font metric <em>X</em> scaled according to font size <em>FS</em>.
-</p></li><li><p>
-Otherwise, set <em>LH</em> to 125% of <em>FS</em>.
-</p></li><li><p>
-Set the computed value of this style property to <em>LH</em>.
-</p></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>If a content author wishes to avoid the possibility of different interpretations of <code>normal</code>, for example, due to differences in
-the set of available fonts, then it is recommended that a 
-<a href="#style-value-length">&lt;length&gt;</a> value expression be used to explicitly specify line height value.</p></div><p>If specified as a <a href="#style-value-length">&lt;length&gt;</a>, then the length must
-be non-negative.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
-the computed line height and the supported line height is minimized. If there are multiple closest supported values equally distant from
-the computed value, then the value most distant from 0, i.e., the largest line height, is used.</p></div><p>The <code>tts:lineHeight</code> style is illustrated by the following example.</p><a id="style-attribute-lineHeight-example-1"></a><table class="example"><caption>Example Fragment – Line Height</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="255px 190px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style tts:fontSize="16px"/&gt;
-  &lt;style <span class="strong">tts:lineHeight="32px"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  He thought he saw an elephant,&lt;br/&gt;
-  That practised on a fife:&lt;br/&gt;
-  He looked again, and found it was&lt;br/&gt;
-  A letter from his wife.&lt;br/&gt;
-  "At length I realise," he said,&lt;br/&gt;
-  "The bitterness of Life.
-"&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-lineHeight-example-1-images"></a><table class="example-images"><caption>Example Rendition – Line Height</caption><tbody><tr><td><img src="images/lineHeight.png" alt="TTML lineHeight style property"></td></tr></tbody></table><p></p><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.16.4. Furthermore, it is the intention of this specification that the
-allocation rectangle of a line be consistent with the <span class="strong">per-inline-height-rectangle</span>
-as defined by <a href="#xsl11">[XSL 1.1]</a>, § 4.5, i.e., that a CSS-style line box stacking strategy be used.
-</p></div></div><div class="div3">
-<h4><a id="style-attribute-opacity"></a>10.2.23 tts:opacity</h4><p>The <code>tts:opacity</code> attribute is used to specify a style property that
-defines the opacity (or conversely, the transparency)
-of marks associated with a region or an area generated by content flowed into a region.</p><p>When presented onto a visual medium, the opacity of the region is applied uniformly and on a linear scale
-to all marks produced by content targeted to the
-region after having applied applied any content element specific opacity to areas generated by that content.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-opacity"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-alpha">&lt;alpha&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td>
-<code>1.0</code>
-</td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>The <code>tts:opacity</code> style is illustrated by the following example.</p><table border="1" class="ednote" summary="Editorial note: Enhance Opacity Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Enhance Opacity Example</b></td><td align="right" valign="top">2013-08-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Enhance opacity example to demonstrate opacity on content elements.</td></tr></table><p></p><a id="style-attribute-opacity-example-1"></a><table class="example"><caption>Example Fragment – Opacity</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1" dur="5s"&gt;
-  &lt;set begin="0s" dur="1s" <span class="strong">tts:opacity="1.00"</span>/&gt;
-  &lt;set begin="1s" dur="1s" <span class="strong">tts:opacity="0.75"</span>/&gt;
-  &lt;set begin="2s" dur="1s" <span class="strong">tts:opacity="0.50"</span>/&gt;
-  &lt;set begin="3s" dur="1s" <span class="strong">tts:opacity="0.25"</span>/&gt;
-  &lt;set begin="4s" dur="1s" <span class="strong">tts:opacity="0.00"</span>/&gt;
-  &lt;style tts:extent="304px 77px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  The sun was shining on the sea
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-opacity-example-1-images"></a><table class="example-images"><caption>Example Rendition – Opacity</caption><tbody><tr><td>
-<img src="images/opacity_0.png" alt="TTML opacity style property - [0,1)">
-</td></tr><tr><td>
-<img src="images/opacity_1.png" alt="TTML opacity style property - [1,2)">
-</td></tr><tr><td>
-<img src="images/opacity_2.png" alt="TTML opacity style property - [2,3)">
-</td></tr><tr><td>
-<img src="images/opacity_3.png" alt="TTML opacity style property - [3,4)">
-</td></tr><tr><td>
-<img src="images/opacity_4.png" alt="TTML opacity style property - [4,5)">
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#css3-color">[CSS3 Color]</a>,
-§ 3.2.</p></div></div><div class="div3">
-<h4><a id="style-attribute-origin"></a>10.2.24 tts:origin</h4><p>The <code>tts:origin</code> attribute is used to specify the
-<em>x</em> and <em>y</em> coordinates of the origin of a
-region area with respect to the origin of the <a href="#terms-root-container-region">root container region</a>.</p><p>If both <code>tts:origin</code> and <a href="#style-attribute-position"><code>tts:position</code></a> attributes are
-specified on an element and <a href="#style-attribute-position"><code>tts:position</code></a> is a supported property,
-then the <code>tts:origin</code> attribute must be ignored for the purpose of presentation processing.</p><p>This attribute may be specified by any element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-origin"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>auto</code> |
-<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>relative to width and height of <a href="#terms-root-container-region">root container region</a></td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute consists of two <a href="#style-value-length">&lt;length&gt;</a> specifications,
-then they must be interpreted as <em>x</em> and <em>y</em> coordinates, where the first specification
-is the <em>x</em> coordinate, and the second specification is the <em>y</em> coordinate.</p><p>If the value of this attribute is <code>auto</code>, then the computed value
-of the style property must be considered to be the same as the origin of the <a href="#terms-root-container-region">root container region</a>.</p><p>If a <code>tts:origin</code> attribute is specified on a <code>div</code> or <code>p</code> element, then that specification must be considered to be
-equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>div</code> or <code>p</code> element, where the
-origin of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
-value of this attribute.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
-the computed origin and the supported origin is minimized. If there are multiple closest supported values equally distant from
-the computed value, then the value least distant from [0,0], i.e., closest to the coordinate space origin, is used.</p></div><p>The <code>tts:origin</code> style is illustrated by the following example.</p><a id="style-attribute-origin-example-1"></a><table class="example"><caption>Example Fragment – Origin</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style <span class="strong">tts:origin="40px 40px"</span>/&gt;
-  &lt;style tts:extent="308px 92px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  "To dine!" she shrieked in dragon-wrath.&lt;br/&gt;
-  "To swallow wines all foam and froth!&lt;br/&gt;
-   To simper at a table-cloth!"
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-origin-example-1-images"></a><table class="example-images"><caption>Example Rendition – Origin</caption><tbody><tr><td><img src="images/origin.png" alt="TTML origin style property"></td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-attribute-overflow"></a>10.2.25 tts:overflow</h4><p>The <code>tts:overflow</code> attribute is used to specify a style property that
-defines whether a region area is clipped or not if the descendant areas of the region overflow
-its extent.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-overflow"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>visible</code> |
-<code>hidden</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>hidden</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#layout-vocabulary-region"><code>region</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>If the value of this attribute is <code>visible</code>, then content should
-not be clipped outside of the affected region.
-If the value is <code>hidden</code>, then content should
-be clipped outside of the affected region.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Unless a manual line break element <code>br</code> is used by the content author,
-a paragraph of a given region will generate no more than one line area in that
-region if the computed values of the <code>tts:overflow</code> and <code>tts:wrapOption</code>
-style properties of the region are <code>visible</code> and <code>noWrap</code>,
-respectively.</p></div><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>hidden</code>.</p><p>The <code>tts:overflow</code> style is illustrated by the following example.</p><a id="style-attribute-overflow-example-1"></a><table class="example"><caption>Example Fragment – Overflow</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="232px 40px"/&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="red"/&gt;
-  &lt;style tts:displayAlign="before"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style tts:fontSize="18px"/&gt;
-  &lt;style tts:wrapOption="noWrap"/&gt;
-  &lt;style <span class="strong">tts:overflow="visible"</span>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:extent="232px 40px"/&gt;
-  &lt;style tts:origin="0px 43px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="red"/&gt;
-  &lt;style tts:displayAlign="before"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style tts:fontSize="18px"/&gt;
-  &lt;style tts:wrapOption="noWrap"/&gt;
-  &lt;style <span class="strong">tts:overflow="hidden"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  "But wait a bit," the Oysters cried,&lt;br/&gt;
-  "Before we have our chat;
-&lt;/p&gt;
-&lt;p region="r2"&gt;
-  For some of us are out of breath,&lt;br/&gt;
-  And all of us are fat!"
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-overflow-example-1-images"></a><table class="example-images"><caption>Example Rendition – Overflow</caption><tbody><tr><td><img src="images/overflow.png" alt="TTML overflow style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the <code>tts:noWrap</code> is set to
-<code>noWrap</code> to prevent automatic line wrapping (breaking);
-if this were not specified, then overflow would occur in the block
-progression direction as opposed to the inline progression direction.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.21.2.</p></div></div><div class="div3">
-<h4><a id="style-attribute-padding"></a>10.2.26 tts:padding</h4><p>The <code>tts:padding</code> attribute is used to specify padding (or inset)
-space on one or more sides of a region or an area generated by content flowed into a region.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-padding"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-length">&lt;length&gt;</a> |
-<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> |
-<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> |
-<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>0px</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>relative to width and height of containing region</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute consists of one <a href="#style-value-length">&lt;length&gt;</a> specification,
-then that length applies to all edges of the affected areas. If the value
-consists of two <a href="#style-value-length">&lt;length&gt;</a> specifications, then the first applies to the
-before and after edges, and the second applies to the start and end edges.
-If three <a href="#style-value-length">&lt;length&gt;</a> specifications are provided, then the first applies to the
-before edge, the second applies to the start and end edges, and the third applies
-to the after edge.
-If four <a href="#style-value-length">&lt;length&gt;</a> specifications are provided, then they apply to before, end,
-after, and start edges, respectively.</p><p>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used to express padding must be non-negative.</p><p>If padding is applied to a <a href="#content-vocabulary-span"><code>span</code></a> element, and content from that element
-is divided across multiple line areas, then the specified padding must be applied at each line break boundary. In contrast,
-within a single line area, if multiple inline areas are generated by the element, then the specified padding must be applied at
-the first and/or last generated inline area within a line area the inline progression order of the containing block level element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The behavior of padding on a <a href="#content-vocabulary-span"><code>span</code></a> element corresponds with the use of
-a CSS <code>box-decoration-break</code> property with the value <code>clone</code> at line breaks and the value <code>slice</code>
-at non-terminal, i.e., non-first and non-last, inline area boundaries, as defined by <a href="#css3-frag">[CSS Fragmentation]</a>, § 5.4.</p></div><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the one-dimensional Euclidean distance between
-the computed padding and the supported padding is minimized on a per-edge basis. If there are multiple closest supported values equally distant from
-the computed value for a given edge, then the value least distant from 0, i.e., the least padding, is used.</p></div><p>The <code>tts:padding</code> style is illustrated by the following example.</p><table border="1" class="ednote" summary="Editorial note: Enhance Padding Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Enhance Padding Example</b></td><td align="right" valign="top">2013-08-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Enhance padding example to demonstrate padding on content elements.</td></tr></table><p></p><a id="style-attribute-padding-example-1"></a><table class="example"><caption>Example Fragment – Padding</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="446px 104px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-  &lt;style <span class="strong">tts:padding="10px 40px"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1" tts:backgroundColor="red"&gt;
-  Just the place for a Snark! I have said it twice:&lt;br/&gt;
-  That alone should encourage the crew.&lt;br/&gt;
-  Just the place for a Snark! I have said it thrice:&lt;br/&gt;
-  What I tell you three times is true.
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p>When rendering an area to which padding applies, the background color that
-applies to the area is rendered into the padded portion of the area.</p><a id="style-attribute-padding-example-1-images"></a><table class="example-images"><caption>Example Rendition – Padding</caption><tbody><tr><td>
-<img src="images/padding.png" alt="TTML padding style property">
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.31.15, except that individual shorthand values map to writing
-mode relative padding values as defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.8.31, 7.8.32, 7.8.33, and 7.8.34.</p></div></div><div class="div3">
-<h4><a id="style-attribute-position"></a>10.2.27 tts:position</h4><p>The <code>tts:position</code> attribute is used as an alternative way to specify the position
-of a region area with respect the <a href="#terms-root-container-region">root container region</a>.</p><p>If both <code>tts:position</code> and <a href="#style-attribute-origin"><code>tts:origin</code></a> attributes are
-specified on an element and <code>tts:position</code> is a supported property,
-then the <code>tts:origin</code> attribute must be ignored for the purpose of presentation processing.</p><p>This attribute may be specified by any element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-position"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-position">&lt;position&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>center</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-tt"><code>tt</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>A percentage value component for a horizontal position offset is relative to the width of the
-positioning area minus the width of the associated region.
-A percentage value component for a vertical position offset is relative to the height of the
-positioning area minus the height of the associated region.</p><p>The following image depicts a position value "75% 50%", where the rectangle with dashed line denotes the positioning area and the rectangle
-with solid line denotes the region being positioned. In this case the region is positioned such that a vertical line located at 75% of its width coincides with
-a vertical line located at 75% of the width of the positioning area, and a horizontal line located at 50% of its height coincides with
-a vertical line located at 50% of the width of the posititoning area.</p><a id="style-attribute-position-percentage-based-positioning"></a><table class="example-images"><caption>Percentage Based Positioning</caption><tbody><tr><td>
-<img src="images/position_0.png" alt="TTML position style property using percentages">
-</td></tr></tbody></table><p>If specified on a <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element, then, if a
-<a href="#terms-related-media-object">related media object</a> exists, the positioning area corresponds with
-the <a href="#terms-related-media-object-region">related media object region</a>, or, if no
-<a href="#terms-related-media-object">related media object</a> exists, the positioning area corresponds with
-an unspecified presentation region determined by the <a href="#terms-document-processing-context">document processing context</a>.
-For other applicable element types, the positioning area corresponds with the content rectangle (content box)
-of the <a href="#terms-root-container-region">root container region</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The <a href="#terms-root-container-region">root container region</a> has no border or padding; consequently, its border, padding, and
-content rectangles (boxes) are coterminous.</p></div><p>If a horizontal or vertical position offset is specified by a <code>tts:position</code> attribute in the form of a scalar value
-on a <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element, then that value must be expressed using pixel (<code>px</code>) units,
-in which case a pixel must be interpreted as a pixel in the <a href="#terms-presentation-context-coordinate-space">presentation context coordinate space</a>
-(and not a pixel in the <a href="#terms-document-coordinate-space">document coordinate space</a>).</p><p>If a <code>tts:position</code> attribute is specified on a <a href="#content-vocabulary-div"><code>div</code></a> or
-<a href="#content-vocabulary-p"><code>p</code></a> element, then that specification must be considered to be
-equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>div</code> or <code>p</code> element, where the
-position of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
-value of this attribute.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
-the computed position and the supported position is minimized. If there are multiple closest supported values equally distant from
-the computed value, then the value least distant from [0,0], i.e., closest to the coordinate space position, is used.</p></div><p>The <code>tts:position</code> style is illustrated by the following example, which positions a region so that it is
-centered in the horizontal dimension and has a bottom edge 10% above the bottom of the positioning area in the vertical dimension.</p><a id="style-attribute-position-example-1"></a><table class="example"><caption>Example Fragment – Position</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style <span class="strong">tts:position="center bottom 10%"</span>/&gt;
-  &lt;style tts:extent="308px 92px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="center"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  "To dine!" she shrieked in dragon-wrath.&lt;br/&gt;
-  "To swallow wines all foam and froth!&lt;br/&gt;
-   To simper at a table-cloth!"
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Position Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Position Example Image</b></td><td align="right" valign="top">2014-11-28</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of position example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-the <code>background-position</code> property defined by <a href="#css3-bb">[CSS Backgrounds and Borders]</a>, § 3.6.</p></div></div><div class="div3">
-<h4><a id="style-attribute-ruby"></a>10.2.28 tts:ruby</h4><p>The <code>tts:ruby</code> attribute is used to specify the application of ruby
-styling.</p><p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
-this attribute applies as a style property only to those element types indicated in the following table.</p><a id="style-property-details-ruby"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>none</code> |
-<code>container</code> |
-<code>base</code> |
-<code>baseContainer</code> |
-<code>text</code> |
-<code>textContainer</code> |
-<code>delimiter</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p></p><p>If the value of this attribute is <code>none</code>, then no ruby semantics apply; otherwise, the ruby semantics enumerated by
-<a href="#ruby-semantics-mapping-table"><b>Table 8-1 – Ruby Semantics Mapping</b></a> apply.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>none</code>.</p><a id="ruby-semantics-mapping-table"></a><table class="common"><caption>Table 8-1 – Ruby Semantics Mapping</caption><col width="25%" span="1"><col width="25%" span="1"><col width="25%" span="1"><col width="25%" span="1"><col span="1"><tbody><tr><th>Category</th><th>tts:ruby</th><th>Annotation <a href="#ruby">[Ruby]</a></th><th>CSS display <a href="#cssruby">[CSS Ruby]</a></th></tr><tr><td>Ruby Container</td><td><code>container</code></td><td><code>ruby</code></td><td><code>ruby</code></td></tr><tr><td>Ruby Base Content</td><td><code>base</code></td><td><code>rb</code></td><td><code>ruby-base</code></td></tr><tr><td>Ruby Text Content</td><td><code>text</code></td><td><code>rt</code></td><td><code>ruby-text</code></td></tr><tr><td>Ruby Base Container</td><td><code>baseContainer</code></td><td><code>rbc</code></td><td><code>ruby-base-container</code></td></tr><tr><td>Ruby Text Container</td><td><code>textContainer</code></td><td><code>rtc</code></td><td><code>ruby-text-container</code></td></tr><tr><td>Ruby Fallback Delimiter</td><td><code>delimiter</code></td><td><code>rp</code></td><td><code>none</code> | <code>inline</code></td></tr></tbody></table><p>When using <code>tts:ruby</code>, the following nesting constraints apply:</p><ul><li><p>if the computed value of <code>tts:ruby</code> is <code>container</code>, then the
-computed value of <code>tts:ruby</code> of all ancestor elements is <code>none</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>container</code>, then the
-computed value of <code>tts:ruby</code> of its first child element is <code>baseContainer</code>
-or <code>base</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>baseContainer</code>, then the
-computed value of <code>tts:ruby</code> of its parent element is <code>container</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>baseContainer</code>, then the
-computed value of <code>tts:ruby</code> of its first child element is <code>base</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>baseContainer</code>, then its
-preceding sibling is <code>null</code> (i.e., no preceding sibling);</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>textContainer</code>, then the
-computed value of <code>tts:ruby</code> of its parent element is <code>container</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>textContainer</code>, then the
-computed value of <code>tts:ruby</code> of its first child element is either <code>text</code> or <code>delimiter</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>textContainer</code>, then the
-computed value of <code>tts:ruby</code> of its preceding sibling is <code>baseContainer</code> or
-<code>textContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>textContainer</code>, then the
-computed value of <code>tts:ruby</code> of no more than one sibling is <code>textContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>base</code>, then the
-computed value of <code>tts:ruby</code> of its parent element is either <code>container</code> or
-<code>baseContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>base</code>, then its
-preceding sibling is either <code>null</code> (i.e., no preceding sibling) or the
-computed value of <code>tts:ruby</code> of its preceding sibling is <code>base</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>base</code> and the
-computed value of <code>tts:ruby</code> of its parent element is <code>container</code>,
-then the computed value of <code>tts:ruby</code> of no sibling is <code>base</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>base</code>, then the
-computed value of <code>tts:ruby</code> of no descendant element is not <code>none</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>text</code>, then the
-computed value of <code>tts:ruby</code> of its parent element is either <code>container</code> or
-<code>textContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>text</code>, then the
-computed value of <code>tts:ruby</code> of its preceding sibling is <code>base</code>,
-<code>text</code>, or <code>delimiter</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>text</code> and the
-computed value of <code>tts:ruby</code> of its parent element is <code>container</code>,
-then the computed value of <code>tts:ruby</code> of no sibling is <code>text</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>text</code>, then the
-computed value of <code>tts:ruby</code> of no descendant element is not <code>none</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>delimiter</code>, then the
-computed value of <code>tts:ruby</code> of its parent element is either <code>container</code> or <code>textContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>delimiter</code>, then the
-computed value of <code>tts:ruby</code> of its preceding sibling is <code>base</code> or
-<code>text</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>delimiter</code>, then the
-computed value of <code>tts:ruby</code> of exactly one sibling is <code>delimiter</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>delimiter</code>, then the
-computed value of <code>tts:ruby</code> of no descendant element is not <code>none</code>;</p></li></ul><p>A validating processor must treat a violation of any of the above constraints as an error.
-For the purpose of presentation processing, the violation of any of these constraints should result in fallback (inline)
-presentation of ruby text annotations.</p><p>When performing normal presentation processing of ruby text annotations, delimiter content must not generate any
-inline areas. When performing fallback presentation of ruby, both delimiter and non-delimiter ruby (base and text) content
-must generate normal inline areas.</p><p>If a presentation processor does not support ruby presentation, then it must perform fallback ruby presentaton.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The above listed constraints are intended to be interpreted as specifying the following nesting model:</p><div class="exampleInner"><pre>
-container
-  : base text
-  | base delimiter text delimiter
-  | baseContainer textContainer textContainer?
-
-baseContainer
-  : base+
-
-textContainer
-  : text+
-  | delimiter text+ delimiter
-
-base | text | delimiter
-  : ( #PCDATA | { span - tts:ruby } )*
-</pre></div><p>This model corresponds to the maximal content model for the <code>ruby</code> element defined by <a href="#ruby">[Ruby]</a>, §2.1,
-with the exception that <code>rtc</code> is effectively extended to permit the optional use of delimiters (<code>rp</code>):</p><div class="exampleInner"><pre>
-ruby
-  : rb rt
-  | rb rp rt rp
-  | rbc rtc rtc?
-
-rbc
-  : rb+
-
-rtc
-  : rt+
-  | rp rt+ rp                            // extension to <a href="#ruby">[Ruby]</a>
-</pre></div></div><div class="note"><p class="prefix"><b>Note:</b></p><p>While not supporting as many opportunities for markup minimization as allowed by <a href="#html5">[HTML5]</a>,
-the formulation of ruby annotation defined here does allow the following shorthands:</p><div class="exampleInner"><pre>
-base text =
-  baseContainer
-    base
-  textContainer
-    text
-
-base delimiter text delimiter =
-  baseContainer
-    base
-  textContainer
-    delimiter text delimiter
-</pre></div><p>Given the content of <code>base</code> is <code>B</code> and the content of
-<code>text</code> is <code>T</code>, then the expression <code>base text</code> could be represented variously in <a href="#html5">[HTML5]</a> as follows:</p><div class="exampleInner"><pre>
-&lt;ruby&gt;B&lt;rt&gt;T&lt;/ruby&gt;
-&lt;ruby&gt;B&lt;rt&gt;T&lt;/rt&gt;&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;rt&gt;T&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rt&gt;T&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/ruby&gt;
-&lt;ruby&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/ruby&gt;
-&lt;ruby&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/rtc&gt;&lt;/ruby&gt;
-&lt;ruby&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/ruby&gt;
-&lt;ruby&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/rtc&gt;&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/rtc&gt;&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rtc&gt;&lt;rt&gt;T&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rtc&gt;&lt;rt&gt;T&lt;/rtc&gt;&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rtc&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/ruby&gt;
-&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rtc&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/rtc&gt;&lt;/ruby&gt;
-</pre></div><p>Whereas, in TTML2, the following alternative expressions are possible:</p><div class="exampleInner"><pre>
-&lt;span tts:ruby="container"&gt;
-  &lt;span tts:ruby="base"&gt;B&lt;/span&gt;
-  &lt;span tts:ruby="text"&gt;T&lt;/span&gt;
-&lt;/span&gt;
-</pre></div><p>or its equivalent</p><div class="exampleInner"><pre>
-&lt;span tts:ruby="container"&gt;
-  &lt;span tts:ruby="baseContainer"&gt;
-    &lt;span tts:ruby="base"&gt;B&lt;/span&gt;
-  &lt;/span&gt;
-  &lt;span tts:ruby="textContainer"&gt;
-    &lt;span tts:ruby="text"&gt;T&lt;/span&gt;
-  &lt;/span&gt;
-&lt;/span&gt;
-</pre></div></div><p>Use of <code>tts:ruby</code> to specify simple ruby annotation is illustrated by the following example.</p><a id="style-attribute-ruby-example-1"></a><table class="example"><caption>Example Fragment – Simple Ruby</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;span <span class="strong">tts:ruby="container"</span>&gt;
-  &lt;span <span class="strong">tts:ruby="base"</span>&gt;利用許諾&lt;/span&gt;
-  &lt;span <span class="strong">tts:ruby="text"</span>&gt;ライセンス&lt;/span&gt;
-&lt;/span&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-ruby-example-1-images"></a><table class="example-images"><caption>Example Rendition – Simple Ruby</caption><tbody><tr><td><img src="images/ruby_1.png" alt="TTML ruby style property"></td></tr></tbody></table><p>Use of <code>tts:ruby</code> to specify complex ruby annotation is illustrated by the following example.</p><a id="style-attribute-ruby-example-2"></a><table class="example"><caption>Example Fragment – Complex Ruby</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;span&gt;
-  &lt;span <span class="strong">tts:ruby="container"</span>&gt;
-    &lt;span <span class="strong">tts:ruby="baseContainer"</span>&gt;
-      &lt;span <span class="strong">tts:ruby="base"</span>&gt;東南&lt;/span&gt;
-    &lt;/span&gt;
-    &lt;span <span class="strong">tts:ruby="textContainer"</span> tts:rubyPosition="before"&gt;
-      &lt;span <span class="strong">tts:ruby="text"</span>&gt;とうなん&lt;/span&gt;
-    &lt;/span&gt;
-    &lt;span <span class="strong">tts:ruby="textContainer"</span> tts:rubyPosition="after"&gt;
-      &lt;span <span class="strong">tts:ruby="text"</span>&gt;たつみ&lt;/span&gt;
-    &lt;/span&gt;
-  &lt;/span&gt;
-  &lt;span&gt;の方角&lt;/span&gt;
-&lt;/span&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-ruby-example-2-images"></a><table class="example-images"><caption>Example Rendition – Complex Ruby</caption><tbody><tr><td><img src="images/ruby_2.png" alt="TTML ruby style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#ruby">[Ruby]</a> and <a href="#cssruby">[CSS Ruby]</a>. See also
-<a href="#jlreq">[JLREQ]</a>, §3.3, for further information.</p></div></div><div class="div3">
-<h4><a id="style-attribute-rubyAlign"></a>10.2.29 tts:rubyAlign</h4><p>The <code>tts:rubyAlign</code> attribute is used to specify the position of ruby text within the inline area generated by the ruby text container annotation.</p><p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
-this attribute applies as a style property only to those element types indicated in the following table.</p><a id="style-property-details-rubyAlign"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>start</code> |
-<code>center</code> |
-<code>spaceBetween</code> |
-<code>spaceAround</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>spaceAround</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a> only if the computed value of <a href="#style-attribute-ruby">tts:ruby</a> is <code>container</code>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p></p><p>If the value of this attribute is <code>start</code>, then the start edge of the first glyph area descendant of an inline area generated from a ruby text container
-or ruby text annotation is aligned to the start edge of that inline area.
-If the value is <code>center</code>, then excess whitespace
-is equally distributed before and after the first and last glyphs, respectively.
-If the value is <code>spaceBetween</code>, then excess whitespace
-is equally distributed between each glyph area descendant.
-If the value is <code>spaceAround</code>, then excess whitespace
-is equally distributed before and after each glyph area descendant.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>spaceAround</code>.</p><table border="1" class="ednote" summary="Editorial note: Ruby Align Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Ruby Align Example</b></td><td align="right" valign="top">2014-09-20</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add example source and rendering of tts:rubyAlign.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#cssruby">[CSS Ruby]</a>, §4.3, and the examples and example
-renderings shown there apply.</p></div></div><div class="div3">
-<h4><a id="style-attribute-rubyOffset"></a>10.2.30 tts:rubyOffset</h4><p>The <code>tts:rubyOffset</code> attribute is used to specify the offset (distance) of ruby text with respect to its associated ruby base
-in the block progression dimension.</p><p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
-this attribute applies as a style property only to those element types indicated in the following table.</p><a id="style-property-details-rubyOffset"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-length">&lt;length&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>0px</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a> only if the computed value of <a href="#style-attribute-ruby">tts:ruby</a> is <code>container</code>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>relative to this element's font size</td></tr><tr><td><em>Animatable:</em></td><td>continuous</td></tr></tbody></table><p></p><p>If specified, the value of <code>tts:rubyOffset</code> expresses the offset (distance) between padding edge <em>E<sub>1</sub></em> of the inline area
-generated by a ruby text container (explicit or implied) and padding edge <em>E<sub>2</sub></em>  of the inline area generated by a ruby base container (explicit or implied), where
-<em>E<sub>1</sub></em> and <em>E<sub>2</sub></em> are perpendicular to the block progression direction and are (or would be) adjacent in the absence of
-such an offset.</p><p>Negative length expressions are permitted.</p><table border="1" class="ednote" summary="Editorial note: Ruby Offset Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Ruby Offset Example</b></td><td align="right" valign="top">2014-10-02</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add example source and rendering of tts:rubyOffset.</td></tr></table></div><div class="div3">
-<h4><a id="style-attribute-rubyPosition"></a>10.2.31 tts:rubyPosition</h4><p>The <code>tts:rubyPosition</code> attribute is used to specify the position of ruby text in the block progression dimension
-with respect to its associated ruby base.</p><table border="1" class="ednote" summary="Editorial note: Outside Annotations"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Outside Annotations</b></td><td align="right" valign="top">2015-01-14</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add <code>auto</code> and <code>outside</code> values as defined by &lt;emphasisPosition&gt; expressions.</td></tr></table><p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
-this attribute applies as a style property only to those element types indicated in the following table.</p><a id="style-property-details-rubyPosition"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>before</code> |
-<code>after</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>before</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a> only if the computed value of <a href="#style-attribute-ruby">tts:ruby</a> is <code>container</code>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p></p><p>If the value of this attribute is <code>before</code>, then an inline area generated from a ruby text container or ruby text annotation
-is placed before (prior to) the first edge in the block progression dimension of the inline area generated from an associated ruby base container or ruby base annotation.
-If the value is <code>after</code>, then an inline area generated from a ruby text container or ruby text annotation
-is placed after (subsequent to) the second edge in the block progression dimension of the inline area generated from an associated ruby base container or ruby base
-annotation.</p><p>The absolute position of the ruby text container or ruby text annotation is determined
-in accordance to the computed value of the <code>tts:writingMode</code> style property of the region into which the affected content is placed; in particular, the
-mappings defined enumerated by <a href="#rubyPosition-semantics-mapping-table"><b>Table 8-2 – Ruby Position Semantics Mapping by Writing Mode</b></a> apply as further defined by <a href="#cssruby">[CSS Ruby]</a>, §4.1.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>before</code>.</p><a id="rubyPosition-semantics-mapping-table"></a><table class="common"><caption>Table 8-2 – Ruby Position Semantics Mapping by Writing Mode</caption><col width="20%" span="1"><col width="20%" span="1"><col width="20%" span="1"><col width="20%" span="1"><col width="20%" span="1"><col span="1"><tbody><tr><th>tts:rubyPosition</th><th><code>lrtb</code></th><th><code>rltb</code></th><th><code>tbrl</code></th><th><code>tblr</code></th></tr><tr><td><code>before</code></td><td><code>over</code></td><td><code>over</code></td><td><code>right</code></td><td><code>left</code></td></tr><tr><td><code>after</code></td><td><code>under</code></td><td><code>under</code></td><td><code>left</code></td><td><code>right</code></td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Ruby Position Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Ruby Position Example</b></td><td align="right" valign="top">2014-09-20</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add example source and rendering of tts:rubyPosition.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#cssruby">[CSS Ruby]</a>, §4.1, and the examples and example
-renderings shown there apply modulo the mappings defined above.</p></div></div><div class="div3">
-<h4><a id="style-attribute-showBackground"></a>10.2.32 tts:showBackground</h4><p>The <code>tts:showBackground</code> attribute is used to specify
-constraints on when the background color of a region is intended to be
-presented.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-showBackground"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>always</code> |
-<code>whenActive</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>always</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#layout-vocabulary-region"><code>region</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>If the value of this attribute is <code>always</code>, then the
-background color of a region is always rendered when performing presentation
-processing on a visual medium; if the value is <code>whenActive</code>,
-then the background color of a region is rendered only when some
-content is flowed into the region.</p><p>A region satisfies the <code>whenActive</code> case if (1) it is a
-<a href="#terms-temporally-active-region">temporally active region</a> and (2) content is selected into the region,
-where that content is also <a href="#terms-temporally-active">temporally active</a>.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>always</code>.</p><p>The <code>tts:showBackground</code> style is illustrated by the following example.</p><a id="style-attribute-showBackground-example-1"></a><table class="example"><caption>Example Fragment – Show Background</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:extent="265px 100px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style <span class="strong">tts:showBackground="always"</span>/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="before"/&gt;
-  &lt;style tts:textAlign="start"/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:origin="205px 60px"/&gt;
-  &lt;style tts:extent="290px 100px"/&gt;
-  &lt;style tts:backgroundColor="red"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="before"/&gt;
-  &lt;style tts:textAlign="end"/&gt;
-  &lt;style <span class="strong">tts:showBackground="whenActive"</span>/&gt;
-&lt;/region&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#smil3">[SMIL 3.0]</a>,
-§ 7.4.2.</p></div></div><div class="div3">
-<h4><a id="style-attribute-textAlign"></a>10.2.33 tts:textAlign</h4><p>The <code>tts:textAlign</code> attribute is used to specify a style property that
-defines how inline areas are aligned within a containing block area in the inline progression
-direction.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textAlign"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>left</code> |
-<code>center</code> |
-<code>right</code> |
-<code>start</code> |
-<code>end</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>start</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>see prose</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>The <code>tts:textAlign</code> attribute is inheritable only on a <a href="#content-vocabulary-p"><code>p</code></a> element. If not
-specified on a <a href="#content-vocabulary-span"><code>span</code></a> element, then the <code>tts:textAlign</code> style property  does not apply to that
-element, rather, normal inline composition and alignment apply.</p><p>If a <code>tts:textAlign</code> attribute is specified on a <a href="#content-vocabulary-span"><code>span</code></a> element,
-then that <a href="#content-vocabulary-span"><code>span</code></a> element must be processed using
-<a href="#terms-inline-block-display">inline block display</a> semantics for the purpose of presentation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <code>tts:textAlign</code> attribute may be used on a <a href="#content-vocabulary-span"><code>span</code></a> element in order
-to force composition using <a href="#terms-inline-block-display">inline block display</a> semantics and to apply a different alignment
-to the resulting nested block area. For example, a paragraph may be composed using center text alignment, while the text content within the paragraph, if
-wrapped in a span, may be composed using left text alignment.</p></div><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>start</code>.</p><p>The <code>tts:textAlign</code> style is illustrated by the following example.</p><a id="style-attribute-textAlign-example-1"></a><table class="example"><caption>Example Fragment – Text Align</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="355px 43px"/&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:textAlign="start"</span>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:extent="355px 43px"/&gt;
-  &lt;style tts:origin="0px 47px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:textAlign="end"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  Beware the Jabberwock, my son!&lt;br/&gt;
-  The jaws that bite, the claws that catch!
-&lt;/p&gt;
-&lt;p region="r2"&gt;
-  Beware the Jubjub bird, and shun&lt;br/&gt;
-  The frumious Bandersnatch!
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-textAlign-example-1-images"></a><table class="example-images"><caption>Example Rendition – Text Align</caption><tbody><tr><td><img src="images/textAlign.png" alt="TTML textAlign style property"></td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Text Align on Span Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Align on Span Example</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of use of tts:textAlign on a span element.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.16.9.</p></div></div><div class="div3">
-<h4><a id="style-attribute-textCombine"></a>10.2.34 tts:textCombine</h4><p>When a vertical writing mode applies, the <code>tts:textCombine</code> attribute is used to specify a style property that
-determines whether and how multiple nominally non-combining characters are combined so that their glyph areas
-consume the nominal bounding box of a single em square. If a horizontal writing mode applies, then this property is ignored
-for the purpose of presentation processing.</p><p>Combination processing may make use of one or more techniques to obtain the goal of visual combination into an em square. For
-example, half-width variant forms may be selected, a ligature may be selected, a smaller font size may be applied, etc. At a minimum, an
-implementation that supports this style property must be able to select half-width variant forms if available.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textCombine"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>none</code> |
-<code>all</code> |
-[ <code>digits</code> <a href="#style-value-non-negative-integer">&lt;non-negative-integer&gt;</a>? ]
-</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If the specified value of this attribute is <code>none</code>, then no combination processing applies.
-If the specified value of this attribute is <code>all</code>, then all affected characters should be combined.
-If the specified value of this attribute is <code>digits</code>, then all affected characters should be combined if they are a sequence of a digits which length is
-equal to or less than a specified count, or two (2) if no count is specified.</p><p>Combination must not cross an element boundary, a bidirectional boundary, or a non-glyph area boundary.</p><p>This attribute has no impact on or interaction with the nominal layout of glyph areas that constitute a Unicode combining character sequence.</p><table border="1" class="ednote" summary="Editorial note: Text Combine Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Combine Example</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:textCombine.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-that defined by <a href="#css3-wm">[CSS Writing Modes]</a>, § 9.1.</p></div></div><div class="div3">
-<h4><a id="style-attribute-textDecoration"></a>10.2.35 tts:textDecoration</h4><p>The <code>tts:textDecoration</code> attribute is used to specify a style property that
-defines a text decoration effect to apply to glyph areas or other inline
-areas that are generated by content flowed into a region.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textDecoration"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>none</code> |
-[ [
-<code>underline</code> |
-<code>noUnderline</code>
-] || [
-<code>lineThrough</code> |
-<code>noLineThrough</code>
-] || [
-<code>overline</code> |
-<code>noOverline</code>
-] ]
-</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td><a href="#content-vocabulary-span"><code>span</code></a></td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this
-style property, each character child of a <code>p</code> element is
-considered to be enclosed in an anonymous span.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>none</code>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The syntax used above in defining the value of this property is based on the
-value component syntax defined in <a href="#css2">[CSS2]</a>, § 1.4.2.1. In essence,
-one or more of the values separated by <code>||</code> may appear in the property
-value in any order, such as <code>"noUnderline overline lineThrough"</code>.</p></div><p>The <code>tts:textDecoration</code> style is illustrated by the following example.</p><a id="style-attribute-textDecoration-example-1"></a><table class="example"><caption>Example Fragment – Text Decoration</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="385px 82px"/&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:padding="5px 2px"/&gt;
-  &lt;style <span class="strong">tts:textDecoration="underline"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  The sea was wet&lt;span <span class="strong">tts:textDecoration="noUnderline"</span>&gt; as &lt;/span&gt;wet
-  &lt;span <span class="strong">tts:textDecoration="noUnderline"</span>&gt;
-    could be,&lt;br/&gt;
-    The sand was dry as dry.&lt;br/&gt;
-    &lt;span <span class="strong">tts:textDecoration="lineThrough"</span>&gt;There weren't any&lt;/span&gt;
-    You &lt;span <span class="strong">tts:textDecoration="lineThrough"</span>&gt;couldn't&lt;/span&gt;
-    could not see a cloud&lt;br/&gt;
-    Because no cloud was in the sky.
-  &lt;/span&gt;
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-textDecoration-example-1-images"></a><table class="example-images"><caption>Example Rendition – Text Decoration</caption><tbody><tr><td><img src="images/textDecoration.png" alt="TTML textDecoration style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.17.4.</p></div></div><div class="div3">
-<h4><a id="style-attribute-textEmphasis"></a>10.2.36 tts:textEmphasis</h4><p>The <code>tts:textEmphasis</code> attribute is used to specify a style property that
-determines whether and how text emphasis marks are presented on affected content.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textEmphasis"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-[
-<a href="#style-value-emphasisStyle">&lt;emphasisStyle&gt;</a> ||
-<a href="#style-value-emphasisColor">&lt;emphasisColor&gt;</a> ||
-<a href="#style-value-emphasisPosition">&lt;emphasisPosition&gt;</a>
-]
-</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous (color only)</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If the specified value of this attribute is <code>auto</code>, then it must be interpreted as if
-<code>auto</code> were specified for both emphasis style and emphasis position components.</p><p>If no emphasis style is specified,
-then the emphasis style must be interpreted as if a style of <code>auto</code> were specified.
-If no emphasis color is specified,
-then the emphasis color must be interpreted as if a color of <code>current</code> were specified.
-If no emphasis position is specified,
-then the emphasis position must be interpreted as if a position of <code>auto</code> were specified.</p><table border="1" class="ednote" summary="Editorial note: Text Emphasis Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Emphasis Example</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:textEmphasis.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-that defined by <a href="#css3-decoration">[CSS Text Decoration]</a>, § 3.</p></div></div><div class="div3">
-<h4><a id="style-attribute-textOrientation"></a>10.2.37 tts:textOrientation</h4><p>The <code>tts:textOrientation</code> attribute is used to specify a style property that
-defines a text orientation to apply to glyphs that are selected for glyph areas generated
-by content flowed into a region to which a vertical writing mode applies.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textOrientation"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>mixed</code> |
-<code>sideways</code> |
-<code>sidewaysLeft</code> |
-<code>sidewaysRight</code> |
-<code>upright</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>mixed</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If the value of this attribute is <code>mixed</code>, then, in vertical writing modes,
-glyphs from horizontal scripts are set sideways, i.e., 90° clockwise from
-their nominal orientation in horizontal text, while glyphs from vertical scripts are not
-affected.</p><p>If the value of this attribute is <code>sidewaysLeft</code>, then, in vertical writing modes,
-glyphs from horizontal scripts are set sideways with 90° counter-clockwise rotation.</p><p>If the value of this attribute is <code>sidewaysRight</code>, then, in vertical writing modes,
-glyphs from horizontal scripts are set sideways with 90° clockwise rotation.</p><p>If the value of this attribute is <code>sideways</code>, then, in vertical writing modes,
-glyphs from horizontal scripts are set sideways, either 90° clockwise or
-90° counter-clockwise, according to whether the writing mode is
-<code>tbrl</code> or <code>tblr</code>, respectively. Glyphs from vertical scripts are not
-affected.</p><p>If the value of this attribute is <code>upright</code>, then, in vertical writing modes,
-glyphs from horizontal scripts are set upright, i.e., using their
-nominal orientation in horizontal text, while glyphs from vertical scripts are not
-affected. In addition, for purposes of bidirectional processing, this value causes all
-affected characters to be treated as strong left-to-right, i.e., to be treated as if
-a <code>tts:direction</code> of <code>ltr</code> and <code>tts:unicodeOverride</code> of
-<code>override</code> were applied.</p><p>If a vertical writing mode does not apply, then this style property has no effect.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>mixed</code>.</p><p>The <code>tts:textOrientation</code> style is illustrated by the following
-example.</p><table border="1" class="ednote" summary="Editorial note: Text Orientation Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Orientation Example</b></td><td align="right" valign="top">2013-08-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:textOrientation.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#css3-wm">[CSS Writing Modes]</a>,
-§ 5.1.</p></div></div><div class="div3">
-<h4><a id="style-attribute-textOutline"></a>10.2.38 tts:textOutline</h4><p>The <code>tts:textOutline</code> attribute is used to specify a style property that
-defines a text outline effect to apply to glyphs that are selected for glyph areas generated
-by content flowed into a region.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textOutline"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>none</code> |
-<a href="#style-value-color">&lt;color&gt;</a>?
-<a href="#style-value-length">&lt;length&gt;</a>
-<a href="#style-value-length">&lt;length&gt;</a>?
-</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>relative to this element's font size</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>The value of this attribute consists of an optional <a href="#style-value-color">&lt;color&gt;</a> term
-followed by one or two <a href="#style-value-length">&lt;length&gt;</a> terms.  If a <em>color</em> term is
-present, then it denotes the outline color; if no <em>color</em> term is
-present, the computed value of the <code>tts:color</code> applies.  The first
-<em>length</em> term denotes the outline thickness and the second length
-term, if present, indicates the blur radius.</p><p>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used to express thickness and blur radius must be non-negative.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When a <a href="#style-value-length">&lt;length&gt;</a> expressed in
-cells is used in a <code>tts:textOutline</code> value,
-the cell's dimension in the block progression dimension applies.
-For example, if text outline thickness is specified as 0.1c, the cell resolution
-is 20 by 10, and the extent of the <a href="#terms-root-container-region">root container region</a> is 640 by 480, then the
-outline thickness will be a nominal 480 / 10 * 0.1 pixels, i.e., 4.8px,
-without taking into account rasterization effects.</p></div><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>none</code>.</p><p>The <code>tts:textOutline</code> style is illustrated by the following
-example.</p><a id="style-attribute-textOutline-example-1"></a><table class="example"><caption>Example Fragment – Text Outline</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:backgroundColor="transparent"/&gt;
-  &lt;style tts:color="yellow"/&gt;
-  &lt;style <span class="strong">tts:textOutline="black 2px 0px"</span>/&gt;
-  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
-  &lt;style tts:fontSize="24px"/&gt;
-&lt;/region&gt;
-...
-&lt;p&gt;
-  How doth the little crocodile&lt;br/&gt;
-  Improve its shining tail,&lt;br/&gt;
-  And pour the waters of the Nile&lt;br/&gt;
-  On every golden scale!&lt;br/&gt;
-  How cheerfully he seems to grin,&lt;br/&gt;
-  How neatly spreads his claws,&lt;br/&gt;
-  And welcomes little fishes in,&lt;br/&gt;
-  With gently smiling jaws!
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-textOutline-example-1-images"></a><table class="example-images"><caption>Example Rendition – Text Outline</caption><tbody><tr><td><img src="images/textOutline.png" alt="textOutline style property"></td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-attribute-textShadow"></a>10.2.39 tts:textShadow</h4><p>The <code>tts:textShadow</code> attribute is used to specify a style property that
-defines one or more text shadow decorations to apply to glyphs that are selected for glyph areas generated
-by content flowed into a region.</p><p>If both <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a> and <code>tts:textShadow</code> attributes
-are specified on an element and <code>tts:textShadow</code> is a supported property,
-then the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a> attribute must be ignored for the purpose of presentation processing.</p><p>If multiple text shadows apply, then they are drawn in the specified order immediately prior to drawing the glyph area to which they apply.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textShadow"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>none</code> |
-[ <a href="#style-value-shadow">&lt;shadow&gt;</a> ]#
-</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>relative to this element's font size</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>none</code>.</p><table border="1" class="ednote" summary="Editorial note: Text Shadow Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Shadow Example</b></td><td align="right" valign="top">2015-01-08</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:textShadow.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
-that defined by <a href="#css3-decoration">[CSS Text Decoration]</a>, § 4.</p></div></div><div class="div3">
-<h4><a id="style-attribute-unicodeBidi"></a>10.2.40 tts:unicodeBidi</h4><p>The <code>tts:unicodeBidi</code> attribute is used to specify a style property that
-defines a directional embedding or override according to
-the Unicode bidirectional algorithm.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-unicodeBidi"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>normal</code> |
-<code>embed</code> |
-<code>bidiOverride</code>
-</td></tr><tr><td><em>Initial:</em></td><td>
-<code>normal</code>
-</td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><p>The <code>tts:unicodeBidi</code> style is illustrated by the following example.</p><a id="style-attribute-unicodeBidi-example-1"></a><table class="example"><caption>Example Fragment – Unicode Bidirectionality</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="265px 84px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:textAlign="center"/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  Little birds are playing&lt;br/&gt;
-  Bagpipes on the shore,&lt;br/&gt;
-  &lt;span <span class="strong">tts:unicodeBidi="bidiOverride"</span> tts:direction="rtl"&gt;where the tourists snore.&lt;/span&gt;
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-unicodeBidi-example-1-images"></a><table class="example-images"><caption>Example Rendition – Unicode Bidirectionality</caption><tbody><tr><td>
-<img src="images/unicodeBidi.png" alt="TTML unicodeBidi style property">
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.29.6.</p></div></div><div class="div3">
-<h4><a id="style-attribute-visibility"></a>10.2.41 tts:visibility</h4><p>The <code>tts:visibility</code> attribute is used to specify a style property that
-defines whether generated areas are visible or not when rendered on a visual
-presentation medium.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-visibility"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>visible</code> |
-<code>hidden</code>
-</td></tr><tr><td><em>Initial:</em></td><td>
-<code>visible</code>
-</td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#layout-vocabulary-region"><code>region</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>The <code>tts:visibility</code> style has no affect on content layout or
-composition, but merely determines whether composed content is visible or not.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>visible</code>.</p><p>The <code>tts:visibility</code> style is illustrated by the following example.</p><a id="style-attribute-visibility-example-1"></a><table class="example"><caption>Example Fragment – Visibility</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="398px 121px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1" dur="4s"&gt;
-  &lt;span <span class="strong">tts:visibility="hidden"</span>&gt;
-    &lt;set begin="1s" <span class="strong">tts:visibility="visible"</span>/&gt;
-    Curiouser
-  &lt;/span&gt;
-  &lt;span <span class="strong">tts:visibility="hidden"</span>&gt;
-    &lt;set begin="2s" <span class="strong">tts:visibility="visible"</span>/&gt;
-    and
-  &lt;/span&gt;
-  &lt;span <span class="strong">tts:visibility="hidden"</span>&gt;
-    &lt;set begin="3s" <span class="strong">tts:visibility="visible"</span>/&gt;
-    curiouser!
-  &lt;/span&gt;
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-visibility-example-1-images"></a><table class="example-images"><caption>Example Rendition – Visibility</caption><tbody><tr><td>
-<img src="images/visibility_0.png" alt="TTML visibility style property - [0,1)">
-</td></tr><tr><td>
-<img src="images/visibility_1.png" alt="TTML visibility style property - [1,2)">
-</td></tr><tr><td>
-<img src="images/visibility_2.png" alt="TTML visibility style property - [2,3)">
-</td></tr><tr><td>
-<img src="images/visibility_3.png" alt="TTML visibility style property - [3,4)">
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.30.17.</p></div></div><div class="div3">
-<h4><a id="style-attribute-width"></a>10.2.42 tts:width</h4><p>The <code>tts:width</code> attribute is used to specify the
-<em>width</em> of an area generated by content flowed into a region.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The term <em>width</em> is interpreted in a writing mode relative manner
-such that <em>width</em> always corresponds to a measure in the inline
-progression direction. Therefore, in horizontal writing modes, <em>width</em> expresses a horizontal measure,
-while, in vertical writing mode, <em>width</em> expresses a vertical measure,
-where horizontal and vertical are always interpreted in an absolute sense.</p></div><p>If a <code>tts:width</code> attribute is specified on a <a href="#content-vocabulary-span"><code>span</code></a> element,
-then that <a href="#content-vocabulary-span"><code>span</code></a> element must be processed using
-<a href="#terms-inline-block-display">inline block display</a> semantics for the purpose of presentation processing.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-width"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<a href="#style-value-measure">&lt;measure&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>,
-<a href="#embedded-content-vocabulary-image"><code>image</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If a <a href="#style-value-measure">&lt;measure&gt;</a> is expressed as a <a href="#style-value-length">&lt;length&gt;</a> value, then it must be non-negative.</p><p>The <code>tts:width</code> style is illustrated by the following example.</p><table border="1" class="ednote" summary="Editorial note: Width Percentage"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Width Percentage</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Specify resolution of percentage value.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Width Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Width Example</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:width.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.15.14, and <a href="#css3-box">[CSS Box Model]</a>, § 9</p></div></div><div class="div3">
-<h4><a id="style-attribute-wrapOption"></a>10.2.43 tts:wrapOption</h4><p>The <code>tts:wrapOption</code> attribute is used to specify a style property that
-defines whether or not automatic line wrapping (breaking) applies within the context of
-the affected element.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-wrapOption"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>wrap</code> |
-<code>noWrap</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>wrap</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#content-vocabulary-span"><code>span</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
-each character child of a <code>p</code> element is considered to be enclosed in an anonymous
-span.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>wrap</code>.</p><p>The <code>tts:wrapOption</code> style is illustrated by the following example.</p><a id="style-attribute-wrapOption-example-1"></a><table class="example"><caption>Example Fragment – Wrap Option</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="192px 117px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:displayAlign="after"/&gt;
-  &lt;style tts:overflow="hidden"/&gt;
-  &lt;style <span class="strong">tts:wrapOption="noWrap"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p&gt;
-  I'll tell thee everything I can:&lt;br/&gt;
-  There's little to relate.&lt;br/&gt;
-  I saw an aged aged man,&lt;br/&gt;
-  A-sitting on a gate.
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-wrapOption-example-1-images"></a><table class="example-images"><caption>Example Rendition – Wrap Option</caption><tbody><tr><td><img src="images/wrapOption.png" alt="TTML wrapOption style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.16.13.</p></div></div><div class="div3">
-<h4><a id="style-attribute-writingMode"></a>10.2.44 tts:writingMode</h4><p>The <code>tts:writingMode</code> attribute is used to specify a style property that
-defines the block and inline progression directions to be used for the purpose of
-stacking block and inline areas within a region area.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-writingMode"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>lrtb</code> |
-<code>rltb</code> |
-<code>tbrl</code> |
-<code>tblr</code> |
-<code>lr</code> |
-<code>rl</code> |
-<code>tb</code>
-</td></tr><tr><td><em>Initial:</em></td><td><code>lrtb</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#layout-vocabulary-region"><code>region</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>lrtb</code>.</p><p>The <code>tts:writingMode</code> style is illustrated by the following example.</p><a id="style-attribute-writingMode-example-1"></a><table class="example"><caption>Example Fragment – Writing Mode</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:extent="50px 570px"/&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:padding="10px 3px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:writingMode="tbrl"</span>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:extent="310px 50px"/&gt;
-  &lt;style tts:origin="70px 120px"/&gt;
-  &lt;style tts:padding="10px 3px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:writingMode="rltb"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  I sometimes dig for buttered rolls,&lt;br/&gt;
-  Or set limed twigs for crabs:
-&lt;/p&gt;
-&lt;p region="r2" tts:direction="rtl" tts:unicodeBidi="bidiOverride"&gt;
-  I sometimes search the grassy knolls for the wheels of Hansom-cabs.
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="style-attribute-writingMode-example-1-images"></a><table class="example-images"><caption>Example Rendition – Writing Mode</caption><tbody><tr><td><img src="images/writingMode.png" alt="TTML writingMode style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the second paragraph in the above example that targets region
-<code>r2</code>, the <code>tts:unicodeBidi</code> and
-<code>tts:direction</code> properties are set to
-<code>bidiOverride</code> and <code>rtl</code>, respectively, in order
-to override the normally left-to-right directionality of characters in
-the Latin script.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.29.7.</p></div></div><div class="div3">
-<h4><a id="style-attribute-zIndex"></a>10.2.45 tts:zIndex</h4><p>The <code>tts:zIndex</code> attribute is used to specify a style property that
-defines the front-to-back ordering of region areas in the case that they overlap.</p><p>This attribute may be specified by any
-element type
-that permits use of attributes in the TT Style Namespace; however, this attribute applies
-as a style property only to those element types indicated in the following table.</p><a id="style-property-details-zIndex"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
-<code>auto</code> |
-<a href="#style-value-integer">&lt;integer&gt;</a>
-</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
-<a href="#layout-vocabulary-region"><code>region</code></a>
-</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous (over integral values only)</td></tr></tbody></table><p>If two areas are associated with the same Z-index value, then, if those areas
-overlap in space, the area(s) generated by lexically subsequent elements must be
-rendered over area(s) generated by lexically prior elements, where lexical
-order is defined as the postorder traversal of a <a href="#terms-document-instance">document instance</a>.</p><p>The semantics of the value <code>auto</code> are those defined by
-<a href="#xsl11">[XSL 1.1]</a>, § 7.30.18, where the <code>tt</code> element
-is considered to establish the root stacking context.</p><p>If a computed value of the property associated with this attribute is not supported,
-then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
-the computed z-index and the supported z-index is minimized. If there are multiple closest supported values equally distant from
-the computed value, then the value least distant from 0, i.e., closest to the base stack level of the current stacking context, is used.</p></div><p>The <code>tts:zIndex</code> style is illustrated by the following example.</p><a id="style-attribute-zIndex-example-1"></a><table class="example"><caption>Example Fragment – Z Index</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  &lt;style tts:origin="0px 0px"/&gt;
-  &lt;style tts:extent="400px 100px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:zIndex="0"</span>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r2"&gt;
-  &lt;style tts:origin="100px 60px"/&gt;
-  &lt;style tts:extent="400px 100px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="red"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:textAlign="end"/&gt;
-  &lt;style <span class="strong">tts:zIndex="1"</span>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r3"&gt;
-  &lt;style tts:origin="0px 120px"/&gt;
-  &lt;style tts:extent="400px 100px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="black"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style <span class="strong">tts:zIndex="2"</span>/&gt;
-&lt;/region&gt;
-&lt;region xml:id="r4"&gt;
-  &lt;style tts:origin="100px 180px"/&gt;
-  &lt;style tts:extent="400px 100px"/&gt;
-  &lt;style tts:padding="5px"/&gt;
-  &lt;style tts:backgroundColor="red"/&gt;
-  &lt;style tts:color="white"/&gt;
-  &lt;style tts:textAlign="end"/&gt;
-  &lt;style <span class="strong">tts:zIndex="3"</span>/&gt;
-&lt;/region&gt;
-...
-&lt;p region="r1"&gt;
-  I passed by his garden, and marked, with one eye,&lt;br/&gt;
-  How the Owl and the Panther were sharing a pie.
-&lt;/p&gt;
-&lt;p region="r2"&gt;
-  The Panther took pie-crust, and gravy, and meat,&lt;br/&gt;
-  While the Owl had the dish as its share of the treat.
-&lt;/p&gt;
-&lt;p region="r3"&gt;
-  When the pie was all finished, the Owl, as a boon,&lt;br/&gt;
-  Was kindly permitted to pocket the spoon:
-&lt;/p&gt;
-&lt;p region="r4"&gt;
-  While the Panther received knife and fork&lt;br/&gt;
-  with a growl,&lt;br/&gt;
-  And concluded the banquet by...
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><p></p><a id="style-attribute-zIndex-example-1-images"></a><table class="example-images"><caption>Example Rendition – Z Index</caption><tbody><tr><td><img src="images/zIndex.png" alt="TTML zIndex style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
-represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
-§ 7.30.18.</p></div></div></div><div class="div2">
-<h3><a id="styling-style-value-expressions"></a>10.3 Styling Value Expressions</h3><p>Style property values include the use of the following expressions:</p><ul><li><p><a href="#style-value-alpha"><b>10.3.1 &lt;alpha&gt;</b></a></p></li><li><p><a href="#style-value-borderColor"><b>10.3.2 &lt;borderColor&gt;</b></a></p></li><li><p><a href="#style-value-borderStyle"><b>10.3.3 &lt;borderStyle&gt;</b></a></p></li><li><p><a href="#style-value-borderWidth"><b>10.3.4 &lt;borderWidth&gt;</b></a></p></li><li><p><a href="#style-value-color"><b>10.3.5 &lt;color&gt;</b></a></p></li><li><p><a href="#style-value-digit"><b>10.3.6 &lt;digit&gt;</b></a></p></li><li><p><a href="#style-value-emphasisColor"><b>10.3.7 &lt;emphasisColor&gt;</b></a></p></li><li><p><a href="#style-value-emphasisStyle"><b>10.3.8 &lt;emphasisStyle&gt;</b></a></p></li><li><p><a href="#style-value-emphasisPosition"><b>10.3.9 &lt;emphasisPosition&gt;</b></a></p></li><li><p><a href="#style-value-familyName"><b>10.3.10 &lt;familyName&gt;</b></a></p></li><li><p><a href="#style-value-genericFamilyName"><b>10.3.11 &lt;genericFamilyName&gt;</b></a></p></li><li><p><a href="#style-value-hexDigit"><b>10.3.12 &lt;hexDigit&gt;</b></a></p></li><li><p><a href="#style-value-integer"><b>10.3.13 &lt;integer&gt;</b></a></p></li><li><p><a href="#style-value-length"><b>10.3.14 &lt;length&gt;</b></a></p></li><li><p><a href="#style-value-measure"><b>10.3.15 &lt;measure&gt;</b></a></p></li><li><p><a href="#style-value-namedColor"><b>10.3.16 &lt;namedColor&gt;</b></a></p></li><li><p><a href="#style-value-non-negative-integer"><b>10.3.17 &lt;non-negative-integer&gt;</b></a></p></li><li><p><a href="#style-value-number"><b>10.3.18 &lt;number&gt;</b></a></p></li><li><p><a href="#style-value-percentage"><b>10.3.19 &lt;percentage&gt;</b></a></p></li><li><p><a href="#style-value-position"><b>10.3.20 &lt;position&gt;</b></a></p></li><li><p><a href="#style-value-shadow"><b>10.3.21 &lt;shadow&gt;</b></a></p></li></ul><p>In the syntax representations defined in this section, no
-linear whitespace (LWSP) is implied or permitted between tokens
-unless explicitly specified.</p><div class="div3">
-<h4><a id="style-value-alpha"></a>10.3.1 &lt;alpha&gt;</h4><p>An &lt;alpha&gt; expression is used to express an opacity value,
-where	0 means fully transparent and 1 means fully opaque.</p><a id="alpha-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;alpha&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;alpha&gt;
-  : <em>float</em>
-</pre></div>
-</td></tr></tbody></table><p>In the above syntax representation, the syntactic element
-<em><code>float</code></em> must adhere to the lexical
-representation defined by <a href="#xsd-2">[XML Schema Part 2]</a>&nbsp;§
-3.2.4.1. If the value represented is less than 0.0,
-then it must be interpreted as equal to 0.0; similarly, if the value
-represented is greater than 1.0, then it must be interpreted as
-1.0. The value NaN must be interpreted as 0.0.</p><p>A specified value for &lt;alpha&gt; should not be <code>NaN</code>,
-less than 0, or greater than 1.</p><p>If a <a href="#terms-presentation-processor">presentation processor</a> does not support a specific,
-valid opacity value, then it must interpret it as being equal to the
-closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
-the computed opacity and the supported opacity is minimized. If there are multiple closest supported values equally distant from
-the computed value, then the value most distant from 0, i.e., the greatest opacity, is used.</p></div></div><div class="div3">
-<h4><a id="style-value-borderColor"></a>10.3.2 &lt;borderColor&gt;</h4><p>A &lt;borderColor&gt; expression is used to express the color of one
-or more borders.</p><a id="borderColor-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;borderColor&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;borderColor&gt;
-  : <a href="#style-value-color">&lt;color&gt;</a>
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-value-borderStyle"></a>10.3.3 &lt;borderStyle&gt;</h4><p>A &lt;borderStyle&gt; expression is used to express the style of one
-or more borders.</p><a id="borderStyle-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;borderStyle&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;borderStyle&gt;
-  : none
-  | dotted
-  | dashed
-  | solid
-  | double
-</pre></div>
-</td></tr></tbody></table><p>The interpretation of <code>dotted</code>, <code>dashed</code>, and <code>double</code> are considered
-to be implementation dependent.</p><p>If an implementation does not recognize or otherwise distinguish one of these border style values, then
-it must be interpreted as if a style of <code>solid</code> were specified; as such, an implementation that
-supports borders must minimally support the <code>solid</code> value.</p></div><div class="div3">
-<h4><a id="style-value-borderWidth"></a>10.3.4 &lt;borderWidth&gt;</h4><p>A &lt;borderWidth&gt; expression is used to express the width of one
-or more borders.</p><a id="borderWidth-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;borderWidth&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;borderWidth&gt;
-  : thin
-  | medium
-  | thick
-  | <a href="#style-value-length">&lt;length&gt;</a>
-</pre></div>
-</td></tr></tbody></table><p>The interpretation of <code>thin</code>, <code>medium</code>, and <code>thick</code> are considered
-to be implementation dependent; however, the resolved lengths of these widths must adhere to the following
-constraints: width(thin) &lt; width(medium); width(medium) &lt; width(thick).</p><p>If a border width is expressed as a <a href="#style-value-length">&lt;length&gt;</a>,
-then it must not take the form of a percentage value; i.e., it must take the form of a scalar value.</p></div><div class="div3">
-<h4><a id="style-value-color"></a>10.3.5 &lt;color&gt;</h4><p>A &lt;color&gt; expression is used to specify a named color, exact RGB color triple,
-or exact RGBA color tuple, where the alpha component, if expressed,
-is maximum (255) at 100% opacity
-and minimum (0) at 0% opacity, and where the applicable color space is
-defined by <a href="#srgb">[SRGB]</a>.</p><a id="color-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;color&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;color&gt;
-  : "#" rrggbb
-  | "#" rrggbbaa
-  | "rgb" "(" r-value "," g-value "," b-value ")"
-  | "rgba" "(" r-value "," g-value "," b-value "," a-value ")"
-  | <a href="#style-value-namedColor">&lt;namedColor&gt;</a>
-
-rrggbb
-  :  <a href="#style-value-hexDigit">&lt;hexDigit&gt;</a>{6}
-
-rrggbbaa
-  :  <a href="#style-value-hexDigit">&lt;hexDigit&gt;</a>{8}
-
-r-value | g-value | b-value | a-value
-  : component-value
-
-component-value
-  : non-negative-integer                    // valid range: [0,255]
-
-non-negative-integer
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-</pre></div>
-</td></tr></tbody></table><p>When expressing RGB component values, these values are considered
-to <span class="strong">not</span> be premultiplied by alpha.</p><p>For the purpose of performing presentation processing such that
-non-opaque or non-transparent alpha or opacity values apply, then the
-semantics of compositing functions are defined with respect to the use of
-the <a href="#srgb">[SRGB]</a> color space for both inputs and outputs of
-the composition function.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of <a href="#srgb">[SRGB]</a> for the stated semantics of
-composition is not meant to prevent an actual processor from using some
-other color space either for internal or external purposes. For
-example, a <a href="#terms-presentation-processor">presentation processor</a> may ultimately convert the SRGB values
-used here to the YUV color space for rendition on a television device.</p></div><p>If a <a href="#terms-presentation-processor">presentation processor</a> does not support a specific,
-valid color or alpha value, then it must interpret it as being equal
-to the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
-the computed color and alpha and the supported color and alpha in the RGB color space is minimized. If there are multiple closest supported values equally distant from
-the computed value, then the value least distant from opaque black <code>rgb(0,0,0,255)</code>, i.e., the closest to opaque black, is used.</p></div></div><div class="div3">
-<h4><a id="style-value-digit"></a>10.3.6 &lt;digit&gt;</h4><p>A &lt;digit&gt; is used to express integers and other types of numbers or tokens.</p><a id="digit-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;digit&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;digit&gt;
-  : "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-value-emphasisColor"></a>10.3.7 &lt;emphasisColor&gt;</h4><p>An &lt;emphasisColor&gt; expression is used to express the color of text
-emphasis marks.</p><a id="emphasisColor-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;emphasisColor&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;emphasisColor&gt;
-  : current
-  | <a href="#style-value-color">&lt;color&gt;</a>
-</pre></div>
-</td></tr></tbody></table><dl><dt class="label"><code>current</code></dt><dd><p>Equivalent to the computed value of <a href="#style-attribute-color"><code>tts:color</code></a> of the affected text.</p></dd><dt class="label"><a href="#style-value-color">&lt;color&gt;</a></dt><dd><p>The specified color.</p></dd></dl><p>If an implementation does not recognize or otherwise distinguish emphasis color value, then
-it must be interpreted as if a style of <code>current</code> were specified; as such, an implementation that
-supports text emphasis marks must minimally support the <code>current</code> value.</p></div><div class="div3">
-<h4><a id="style-value-emphasisStyle"></a>10.3.8 &lt;emphasisStyle&gt;</h4><p>An &lt;emphasisStyle&gt; expression is used to express the style of text
-emphasis marks.</p><a id="emphasisStyle-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;emphasisStyle&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;emphasisStyle&gt;
-  : none
-  | auto 
-  | [ filled | open ] || [ circle | dot | sesame ]
-  | <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
-</pre></div>
-</td></tr></tbody></table><p>The semantics of text emphasis style values are defined as follows:</p><dl><dt class="label"><code>none</code></dt><dd><p>No text emphasis mark.</p></dd><dt class="label"><code>auto</code></dt><dd><p>If a vertical writing mode applies, then equivalent to <code>filled sesame</code>; otherwise,
-equivalent to <code>filled circle</code>.</p></dd><dt class="label"><code>filled</code></dt><dd><p>Emphasis mark is filled with emphasis color.</p></dd><dt class="label"><code>open</code></dt><dd><p>Emphasis mark is not filled, i.e., its outline is stroked with the emphasis color, but it is not filled.</p></dd><dt class="label"><code>circle</code></dt><dd><p>Emphasis mark is a circle. If filled, then equivalent to U+25CF '●'; if open, then equivalent to U+25CB '○'</p></dd><dt class="label"><code>dot</code></dt><dd><p>Emphasis mark is a dot. If filled, then equivalent to U+2022 '•'; if open, then equivalent to U+25E6 '◦'</p></dd><dt class="label"><code>sesame</code></dt><dd><p>Emphasis mark is a sesame. If filled, then equivalent to U+FE45 '﹅'; if open, then equivalent to U+FE46 '﹆'</p></dd><dt class="label"><a href="#content-value-quoted-string">&lt;quoted-string&gt;</a></dt><dd><p>Emphasis mark is the first grapheme cluster of string, with remainder of string ignored.</p></dd></dl><p>If only <code>filled</code> or <code>open</code> is specified, then it is equivalent to <code>filled circle</code> and <code>open circle</code>, respectively.</p><p>If only <code>circle</code>, <code>dot</code>, or <code>sesame</code> is specified, then it is equivalent to <code>filled circle</code>, <code>filled dot</code>, and
-<code>filled sesame</code>, respectively.</p><p>If an implementation does not recognize or otherwise distinguish an emphasis style value, then
-it must be interpreted as if a style of <code>auto</code> were specified; as such, an implementation that
-supports text emphasis marks must minimally support the <code>auto</code> value.</p></div><div class="div3">
-<h4><a id="style-value-emphasisPosition"></a>10.3.9 &lt;emphasisPosition&gt;</h4><p>An &lt;emphasisPosition&gt; expression is used to express the position of text
-emphasis marks.</p><a id="emphasisPosition-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;emphasisPosition&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;emphasisPosition&gt;
-  : auto
-  | before
-  | after
-  | outside
-</pre></div>
-</td></tr></tbody></table><dl><dt class="label"><code>auto</code></dt><dd><p>If the containing block area consists of exactly two line areas, then equivalent to <code>outside</code>; otherwise,
-equivalent to <code>before</code>.</p></dd><dt class="label"><code>before</code></dt><dd><p>Towards the before edge of the affected glyph areas. If a horizontal writing mode applies, then this is towards the
-top of the glyph areas. If a vertical writing mode applies, then this is either towards the right or left of the glyph
-areas, according to whether <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a> resolves to
-<code>tbrl</code> or <code>tblr</code>, respectively.</p></dd><dt class="label"><code>after</code></dt><dd><p>Towards the after edge of the affected glyph areas. If a horizontal writing mode applies, then this is towards the
-bottom of the glyph areas. If a vertical writing mode applies, then this is either towards the left or right of the glyph
-areas, according to whether <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a> resolves to
-<code>tbrl</code> or <code>tblr</code>, respectively.</p></dd><dt class="label"><code>outside</code></dt><dd><p>Equivalent to <code>before</code> for all but the last affected line area; otherwise, equivalent to <code>after</code>
-for the last affected line area.</p></dd></dl><p>If an implementation does not recognize or otherwise distinguish an emphasis position value, then
-it must be interpreted as if a position of <code>auto</code> were specified; as such, an implementation that
-supports text emphasis marks must minimally support the <code>auto</code> value.</p></div><div class="div3">
-<h4><a id="style-value-familyName"></a>10.3.10 &lt;familyName&gt;</h4><p>A &lt;familyName&gt; expression specifies a font family name.</p><a id="familyName-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;familyName&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;familyName&gt;
-  : unquoted-string
-  | <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
-
-unquoted-string
-  : identifier ( lwsp identifier )*
-
-lwsp
-  : ( ' ' | '\t' | '\n' | '\r' )+
-
-identifier
-  : [-]? identifier-start identifier-following*
-
-identifier-start
-  : [_a-zA-Z]
-  | non-ascii-or-c1
-  | escape
-
-identifier-following
-  : [_a-zA-Z0-9-]
-  | non-ascii-or-c1
-  | escape
-
-non-ascii-or-c1
-  : [^\0-\237]
-
-escape
-  : '\\' <em>char</em>
-</pre></div>
-
-</td></tr></tbody></table><p>In addition to adhering to the syntax rules specified above, the following semantic rules apply:</p><ul><li><p>the semantic value of a &lt;familyName&gt; expression is the semantic value of its <code>unquoted-string</code> or <code>quoted-string</code>
-non-terminal, according to whichever applies;</p></li><li><p>the semantic value of an <code>unquoted-string</code> non-terminal is a pair <code>&lt;</code><em>quoted</em>, <em>content</em><code>&gt;</code>,
-where <em>quoted</em> is a boolean <code>false</code>, and
-where <em>content</em> is the result of appending the value of each <code>identifier</code>
-non-terminal, in lexical order, where the value of each identifier is preceded by a single SPACE (U+0020) character if it is not the first
-identifier;</p></li><li><p>the semantic value of a <code>quoted-string</code> non-terminal is a pair <code>&lt;</code><em>quoted</em>, <em>content</em><code>&gt;</code>,
-where <em>quoted</em> is a boolean <code>true</code>, and
-where <em>content</em> is the unquoted content of the quoted string, i.e., the sequence of characters between the delimiting quotes.</p></li><li><p>the semantic value of an <code>escape</code> non-terminal is the value of the escaped <code>char</code>;</p></li><li><p>a &lt;familyName&gt; that takes the form of an <code>unquoted-string</code> that contains an <code>identifier</code> that
-starts with two <code>-</code> HYPHEN-MINUS (U+002D) characters must be considered to be invalid;</p></li><li><p>a &lt;familyName&gt; that takes the form of an <code>unquoted-string</code> that contains a single <code>identifier</code> that
-matches (by case sensitive comparison) a &lt;genericFamilyName&gt; must be interpreted as that &lt;genericFamilyName&gt;;</p></li><li><p>a &lt;familyName&gt; that takes the form of a <code>quoted-string</code> whose content (unquoted value)
-matches (by case sensitive comparison) a &lt;genericFamilyName&gt; must not be interpreted as that &lt;genericFamilyName&gt;, but as
-the actual name of a non-generic font family.</p></li><li><p>The syntactic element <em><code>char</code></em> is to be interpreted according
-to the <code>Char</code> production defined by <a href="#xml10">[XML 1.0]</a>&nbsp;§2.2.</p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>The <code>{unicode}</code> escape mechanism defined by <a href="#css2">[CSS2]</a>&nbsp;§4.1.1
-is not supported by this syntax; rather, authors are expected to either (1) directly encode the character
-using the document encoding or (2) use an XML character reference according to
-<a href="#xml10">[XML 1.0]</a>&nbsp;§4.1. When a syntactically significant character needs to be used
-without its normal syntactic interpretation, it may be be escaped using the backslash
-(reverse solidus) <code>escape</code> non-terminal specified above.</p><p>When using the backslash (reverse solidus) <code>escape</code> non-terminal, the above syntax does
-not place any restriction on what character may be escaped, e.g., <code>\\[\n\r\f0-9a-f]</code> are
-permitted. If one of these latter escapes appears in a &lt;familyName&gt; expression, then it will
-need to be converted to a <code>{unicode}</code> escape if it is to be used with a standard XSL-FO
-or CSS parser. In particular, a backslash followed by a newline is ignored by CSS, while it is not
-ignored by the above syntax. Such an unignored escaped newline would need to be represented using
-an equivalent <code>{unicode}</code> escape, such as <code>\a</code>, to order to express in CSS.</p></div></div><div class="div3">
-<h4><a id="style-value-genericFamilyName"></a>10.3.11 &lt;genericFamilyName&gt;</h4><p>A &lt;genericFamilyName&gt; expression specifies a font family using a general
-token that indicates a class of font families.</p><p>The resolution of a generic family name to a concrete font instance is considered to
-be implementation dependent, both in the case of content authoring and content interpretation.</p><a id="genericFamilyName-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;genericFamilyName&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;genericFamilyName&gt;
-  : "default"
-  | "monospace"
-  | "sansSerif"
-  | "serif"
-  | "monospaceSansSerif"
-  | "monospaceSerif"
-  | "proportionalSansSerif"
-  | "proportionalSerif"
-</pre></div>
-</td></tr></tbody></table><p>The mapping between a generic (font) family name and an actual font is not
-determined by this specification; however, the
-distinction of monospace versus proportional and serif versus sans-serif
-should be maintained if possible when performing presentation.</p><p>If a generic (font) family name of <code>monospace</code> is specified,
-then it may be interpreted as equivalent to either <code>monospaceSansSerif</code>
-or <code>monospaceSerif</code>. The generic family names <code>sansSerif</code>
-and <code>serif</code> are to be interpreted as equivalent to <code>proportionalSansSerif</code>
-and <code>proportionalSerif</code>, respectively.</p><p>If the generic family name <code>default</code> is specified (or implied by
-an initial value), then its typographic characteristics are considered to be implementation
-dependent; however, it is recommended that this default font family be mapped to
-an monospaced, sans-serif font.</p></div><div class="div3">
-<h4><a id="style-value-hexDigit"></a>10.3.12 &lt;hexDigit&gt;</h4><p>A &lt;hexDigit&gt; is used to express integers and other types of numbers or tokens
-that employ base 16 arithmetic.</p><p>For the purpose of parsing, a distinction must not be made between lower and upper case.</p><a id="hexDigit-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;hexDigit&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;hexDigit&gt;
-  : <a href="#style-value-digit">&lt;digit&gt;</a>
-  | "a" | "b" | "c" | "d" | "e" | "f"
-  | "A" | "B" | "C" | "D" | "E" | "F"
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-value-integer"></a>10.3.13 &lt;integer&gt;</h4><p>An &lt;integer&gt; expression is used to express an arbitrary, signed integral value.</p><a id="integer-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;integer&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;integer&gt;
-  : ( "+" | "-" )? <a href="#style-value-non-negative-integer">&lt;non-negative-integer&gt;</a>
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-value-length"></a>10.3.14 &lt;length&gt;</h4><p>A &lt;length&gt; expression is used to express either a coordinate component of point
-in a cartesian space or a distance between two points in a cartesian space.</p><a id="length-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;length&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;length&gt;
-  : scalar
-  | <a href="#style-value-percentage">&lt;percentage&gt;</a>
-
-scalar
-  : <a href="#style-value-percentage">&lt;number&gt;</a> units
-
-units
-  : "px"
-  | "em"
-  | "c"                                     // abbreviation of "cell"
-  | "vw"
-  | "vh"
-</pre></div>
-</td></tr></tbody></table><p>It is an error to omit the units component of a scalar length
-value.</p><p>The semantics of
-the unit of measure <code>px</code> (pixel) 
-are as defined by <a href="#xsl11">[XSL 1.1]</a>, § 5.9.13.</p><div class="issue"><p class="prefix"><a id="issue-179"></a><b>Issue (issue-179):</b></p><p class="prefix"><b>Definition of Pixel</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/179">http://www.w3.org/AudioVideo/TT/tracker/issues/179</a></p><p>Replace unworkable (and unadopted) definition of pixel with an appropriate definition based on units of some viewport coordinate space.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>When specified relative to a font whose size is expressed as a single length
-measure or as two length measures of equal length, the unit of measure <code>em</code> is considered to be
-identical to that defined by <a href="#xsl11">[XSL 1.1]</a>, § 5.9.13;
-however, when specified relative to a font whose size is expressed as
-two length measures of non-equal lengths, then one <code>em</code> is
-equal to the inline progression dimension of the anamorphically
-scaled font when used to specify lengths in the inline progression
-direction and equal to the block progression dimension of the scaled
-font when used to specify lengths in the block progression direction.</p><p>The semantics of the unit of measure <code>c</code> (cell) are
-defined by the parameter <a href="#parameter-attribute-cellResolution"><b>7.2.1 ttp:cellResolution</b></a>.</p><p>The units of measure <code>vw</code> and <code>vh</code> are defined as
-one percent (1%) of the width and height of the <a href="#terms-root-container-region">root container region</a>, respectively.
-For example, the length <code>25vw</code> is interpreted as 25% of the width of
-the <a href="#terms-root-container-region">root container region</a>.</p></div><div class="div3">
-<h4><a id="style-value-measure"></a>10.3.15 &lt;measure&gt;</h4><p>A &lt;measure&gt; value expresses a distance used to measure an allocation
-dimension in either the inline progression direction or the block progression direction, where
-the direction that applies is determined by the context of use.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The terms <em>width</em> and <em>height</em> are interpreted in a writing mode relative manner
-such that <em>width</em> always corresponds to a measure in the inline
-progression direction and <em>height</em> always corresponds to a measure in the block progression direction.
-Therefore, in horizontal writing modes, <em>width</em> expresses a horizontal measure
-and <em>height</em> expresses a vertical measure, while, in vertical writing mode, <em>width</em> expresses a vertical measure
-and <em>height</em> expresses a horizontal measure, where horizontal and vertical are always interpreted in an absolute sense.</p></div><a id="measure-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;measure&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;measure&gt;
-  : auto
-  | available
-  | fitContent
-  | maxContent
-  | minContent
-  | <a href="#style-value-length">&lt;length&gt;</a>
-</pre></div>
-</td></tr></tbody></table><p>The semantics of measure values are defined as follows:</p><dl><dt class="label"><code>auto</code></dt><dd><p>As determined by <a href="#semantics-style-automatic-measure-calculation"><b>10.4.5 Automatic Measure Calculation</b></a>.</p></dd><dt class="label"><code>available</code></dt><dd><p>For width in a horizontal writing mode, the numeric value equal to the width of the parent containing block's width less
-the current element's combined border and padding width.
-For height in a horizontal writing mode, the numeric value equal to the height of the parent containing block's height less
-the current element's combined border and padding height.</p><p>For vertical writing mode, the sense of width and height is reversed.</p></dd><dt class="label"><code>fitContent</code></dt><dd><p>A numeric value equal to the maximum of the values of (1) <code>minContent</code> and (2) the minimum of values of <code>maxContent</code> and <code>available</code>.</p></dd><dt class="label"><code>maxContent</code></dt><dd><p>For width in a horizontal writing mode, the maximum numeric value that encloses all of the element's content such that lines are broken only at
-hard, i.e., mandatory, break points, even if that means overflowing the parent's width.</p><p>For height in a horizontal writing mode, the maximum numeric value that encloses all of the element's content such that lines are broken at
-all possible line break positions, i.e., both hard (mandatory) and soft (optional) break points.</p><p>For vertical writing mode, the sense of width and height is reversed.</p></dd><dt class="label"><code>minContent</code></dt><dd><p>For width in a horizontal writing mode, the minimum numeric value that encloses all of the element's content such that lines are broken at
-all possible line break positions, i.e., both hard (mandatory) and soft (optional) break points.</p><p>For height in a horizontal writing mode, the minimum numeric value that encloses all of the element's content such that lines are broken only at
-hard, i.e., mandatory, break points, even if that means overflowing the parent's width.</p><p>For vertical writing mode, the sense of width and height is reversed.</p></dd><dt class="label"><code><a href="#style-value-length">&lt;length&gt;</a></code></dt><dd><p>A non-negative numeric value expressed as a scalar or percentage.</p></dd></dl></div><div class="div3">
-<h4><a id="style-value-namedColor"></a>10.3.16 &lt;namedColor&gt;</h4><p>A &lt;namedColor&gt; is used to express an RGBA color with a convenient name, and where the applicable color space is
-defined by <a href="#srgb">[SRGB]</a>.</p><p>For the purpose of parsing, a distinction must not be made between lower and upper case.</p><a id="namedColor-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;namedColor&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;namedColor&gt;
-  : "transparent"                           // #00000000
-  | "black"                                 // #000000ff
-  | "silver"                                // #c0c0c0ff
-  | "gray"                                  // #808080ff
-  | "white"                                 // #ffffffff
-  | "maroon"                                // #800000ff
-  | "red"                                   // #ff0000ff
-  | "purple"                                // #800080ff
-  | "fuchsia"                               // #ff00ffff
-  | "magenta"                               // #ff00ffff (= fuchsia)
-  | "green"                                 // #008000ff
-  | "lime"                                  // #00ff00ff
-  | "olive"                                 // #808000ff
-  | "yellow"                                // #ffff00ff
-  | "navy"                                  // #000080ff
-  | "blue"                                  // #0000ffff
-  | "teal"                                  // #008080ff
-  | "aqua"                                  // #00ffffff
-  | "cyan"                                  // #00ffffff (= aqua)
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>Except for <code>transparent</code>, the set of named colors specified above constitutes a proper
-subset of the set of named colors specified by <a href="#svg11">[SVG 1.1]</a>, § 4.2.</p></div></div><div class="div3">
-<h4><a id="style-value-non-negative-integer"></a>10.3.17 &lt;non-negative-integer&gt;</h4><p>A &lt;non-negative-integer&gt; expression is used to express an arbitrary, non-negative integral value.</p><a id="non-negative-integer-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;non-negative-integer&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;non-negative-integer&gt;
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-value-number"></a>10.3.18 &lt;number&gt;</h4><p>An &lt;number&gt; expression is used to express an arbitrary, signed integer or real valued number.</p><a id="number-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;number&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;number&gt;
-  : sign? non-negative-number
-
-sign
-  : "+" | "-"
-
-number
-
-non-negative-number
-  : <a href="#style-value-non-negative-integer">&lt;non-negative-integer&gt;</a>
-  | non-negative-real
-
-non-negative-real
-  : <a href="#style-value-digit">&lt;digit&gt;</a>* "." <a href="#style-value-digit">&lt;digit&gt;</a>+
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-value-percentage"></a>10.3.19 &lt;percentage&gt;</h4><p>An &lt;percentage&gt; expression is used to express an arbitrary, signed integral or real valued percentage.</p><a id="percentage-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;percentage&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;percentage&gt;
-  : <a href="#style-value-number">&lt;number&gt;</a> "%"
-</pre></div>
-</td></tr></tbody></table></div><div class="div3">
-<h4><a id="style-value-position"></a>10.3.20 &lt;position&gt;</h4><p>A &lt;position&gt; expression is used to indirectly determine the origin of an area or an image with respect to a reference area.</p><a id="position-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;position&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;position&gt;
-  : offset-position-h                       // single component value
-  | offset-position-v                       // single component value
-  | offset-position-h offset-position-v     // two component values
-  | position-keyword-h edge-offset-v        // three component values
-  | position-keyword-v edge-offset-h        // three component values
-  | edge-offset-h position-keyword-v        // three component values
-  | edge-offset-v position-keyword-h        // three component values
-  | edge-offset-h edge-offset-v             // four component values
-  | edge-offset-v edge-offset-h             // four component values
-
-offset-position-h
-  : position-keyword-h
-  | <a href="#style-value-length">&lt;length&gt;</a>
-
-offset-position-v
-  : position-keyword-v
-  | <a href="#style-value-length">&lt;length&gt;</a>
-
-edge-offset-h
-  : edge-keyword-h <a href="#style-value-length">&lt;length&gt;</a>
-
-edge-offset-v
-  : edge-keyword-v <a href="#style-value-length">&lt;length&gt;</a>
-
-position-keyword-h
-  : center
-  | edge-keyword-h
-
-position-keyword-v
-  : center
-  | edge-keyword-v
-
-edge-keyword-h
-  : left
-  | right
-
-edge-keyword-v
-  : top
-  | bottom
-</pre></div>
-</td></tr></tbody></table><p>A &lt;position&gt; expression may consist of one to four component values as follows:</p><dl><dt class="label">one component</dt><dd><p>either a horizontal offset (<code>offset-position-h</code>) or a vertical offset (<code>offset-position-v</code>)</p></dd><dt class="label">two components</dt><dd><p>a horizontal offset (<code>offset-position-h</code>) followed by a vertical offset (<code>offset-position-v</code>)</p></dd><dt class="label">three components</dt><dd><p>a horizontal edge offset (<code>edge-offset-position-h</code>) and a vertical edge offset (<code>edge-offset-position-v</code>), in any order, where one offset is a keyword and the other offset is a keyword <a href="#style-value-length">&lt;length&gt;</a> pair</p></dd><dt class="label">four components</dt><dd><p>a horizontal edge offset (<code>edge-offset-position-h</code>) and a vertical edge offset (<code>edge-offset-position-v</code>), in any order, where both offsets are keyword <a href="#style-value-length">&lt;length&gt;</a> pairs</p></dd></dl><p>Every &lt;position&gt; expression can be translated to a four component equivalent of the form
-<code>left <a href="#style-value-length">&lt;length&gt;</a> top <a href="#style-value-length">&lt;length&gt;</a></code> by means of the following
-equivalence tables:</p><a id="position-expression-one-component-equivalents"></a><table class="common"><caption>One Component Equivalents</caption><col width="25%" span="1"><col width="25%" span="1"><tbody><tr><th>Value</th><th>Equivalent</th></tr><tr><td><code>center</code></td><td><code>center center</code></td></tr><tr><td><code>left</code></td><td><code>left center</code></td></tr><tr><td><code>right</code></td><td><code>right center</code></td></tr><tr><td><code>top</code></td><td><code>center top</code></td></tr><tr><td><code>bottom</code></td><td><code>center bottom</code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a></code></td><td><code><a href="#style-value-length">&lt;length&gt;</a> center</code></td></tr></tbody></table><p></p><a id="position-expression-two-component-equivalents"></a><table class="common"><caption>Two Component Equivalents</caption><col width="25%" span="1"><col width="25%" span="1"><tbody><tr><th>Value</th><th>Equivalent</th></tr><tr><td><code>center center</code></td><td><code>left 50% top 50%</code></td></tr><tr><td><code>center top</code></td><td><code>left 50% top 0%</code></td></tr><tr><td><code>center bottom</code></td><td><code>left 50% top 100%</code></td></tr><tr><td><code>center <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 50% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>left center</code></td><td><code>left 0% top 50%</code></td></tr><tr><td><code>left top</code></td><td><code>left 0% top 0%</code></td></tr><tr><td><code>left bottom</code></td><td><code>left 0% top 100%</code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 0% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>right center</code></td><td><code>left 100% top 50%</code></td></tr><tr><td><code>right top</code></td><td><code>left 100% top 0%</code></td></tr><tr><td><code>right bottom</code></td><td><code>left 100% top 100%</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 100% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a> top</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a> bottom</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr></tbody></table><p></p><a id="position-expression-three-component-equivalents"></a><table class="common"><caption>Three Component Equivalents</caption><col width="25%" span="1"><col width="25%" span="1"><tbody><tr><th>Value</th><th>Equivalent</th></tr><tr><td><code>bottom left <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code>bottom right <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>left 50% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length&gt;</a> left</code></td><td><code>left 0% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length&gt;</a> right</code></td><td><code>left 100% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>center bottom <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 50% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>center left <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code>center right <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code>center top <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 50% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>left bottom <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 0% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>left top <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 0% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length&gt;</a> bottom</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code>right bottom <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 100% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>right top <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 100% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length&gt;</a> bottom</code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top</code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code>top left <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code>top right <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>left 50% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length&gt;</a> left</code></td><td><code>left 100% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length&gt;</a> right</code></td><td><code>left 100% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr></tbody></table><p></p><a id="position-expression-four-component-equivalents"></a><table class="common"><caption>Four Component Equivalents</caption><col width="25%" span="1"><col width="25%" span="1"><tbody><tr><th>Value</th><th>Equivalent</th></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length-v&gt;</a> left <a href="#style-value-length">&lt;length-h&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length-h&gt;</a> top (100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code></td></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length-v&gt;</a> right <a href="#style-value-length">&lt;length-h&gt;</a></code></td><td><code>left (100% - <a href="#style-value-length">&lt;length-h&gt;</a>) top (100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length-h&gt;</a> bottom <a href="#style-value-length">&lt;length-v&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length-h&gt;</a> top (100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length-h&gt;</a> bottom <a href="#style-value-length">&lt;length-v&gt;</a></code></td><td><code>left (100% - <a href="#style-value-length">&lt;length-h&gt;</a>) top (100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length-h&gt;</a> top <a href="#style-value-length">&lt;length-v&gt;</a></code></td><td><code>left (100% - <a href="#style-value-length">&lt;length-h&gt;</a>) top <a href="#style-value-length">&lt;length-v&gt;</a></code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length-v&gt;</a> left <a href="#style-value-length">&lt;length-h&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length-h&gt;</a> top <a href="#style-value-length">&lt;length-v&gt;</a></code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length-v&gt;</a> right <a href="#style-value-length">&lt;length-h&gt;</a></code></td><td><code>left (100% - <a href="#style-value-length">&lt;length-h&gt;</a>) top <a href="#style-value-length">&lt;length-v&gt;</a></code></td></tr></tbody></table><p>If a <a href="#style-value-length">&lt;length&gt;</a> component is expressed as a percentage, then that percentage is interpreted in relation to
-some reference dimension, where the reference dimension is defined by the context of use.</p><p>A <a href="#style-value-length">&lt;length&gt;</a> component of a &lt;position&gt; expression may be positive or negative. Positive lengths are interpreted as
-insets from the referenced edge, while negative lengths are interpreted as outsets from the referenced edge. For example, an inset from the <code>left</code>
-edge is located to the right of that edge (if non-zero), while an outset from the <code>left</code> edge is located to the left of that edge (if non-zero). In
-contrast, an inset from the <code>right</code> edge is located to the left of that edge (if non-zero), while an outset from the <code>right</code> edge
-is located to the right of that edge (if non-zero). A similar arrangement holds for <code>top</code> and <code>bottom</code> edges.</p><p>When performing four component equivalent conversion, the expression <code>(100% - <a href="#style-value-length">&lt;length-h&gt;</a>)</code>
-is to be interpreted as the difference between 100% and the percentage equivalent of the <a href="#style-value-length">&lt;length-h&gt;</a>
-expression. Similarly, the expression <code>(100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code>
-is to be interpreted as the difference between 100% and the percentage equivalent of the <a href="#style-value-length">&lt;length-v&gt;</a> expression.
-In both cases, the resulting difference may be a negative percentage.</p></div><div class="div3">
-<h4><a id="style-value-shadow"></a>10.3.21 &lt;shadow&gt;</h4><p>A &lt;shadow&gt; value expresses a shadow decoration to be applied to a generated area. If
-the generated area is a glyph area, then it applies to the outline of the glyph (not the glyph area bounding box). If the
-generated area is not a glyph area, then it applies to the border rectangle of the area.</p><a id="shadow-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;shadow&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;shadow&gt;
-  : inset? &amp;&amp; <a href="#style-value-length">&lt;length&gt;</a>{2,4} &amp;&amp; <a href="#style-value-color">&lt;color&gt;</a>
-</pre></div>
-</td></tr></tbody></table><p>A shadow value expression consists of an optional <code>inset</code> token term,
-two to four <a href="#style-value-length">&lt;length&gt;</a> terms, and
-an optional <a href="#style-value-color">&lt;color&gt;</a> term.</p><p>The first <a href="#style-value-length">&lt;length&gt;</a> term denotes the offset in the inline progression direction of the associated area,
-where positive denotes towards the end edge and negative towards the start edge,
-the second <a href="#style-value-length">&lt;length&gt;</a> term denotes the offset in the block progression direction of the associated area,
-where positive denotes towards the after edge and negative towards the before edge.
-The third <a href="#style-value-length">&lt;length&gt;</a> term, if present, denotes the blur radius, and must be non-negative.
-The fourth <a href="#style-value-length">&lt;length&gt;</a> term, if present, denotes the spread distance, where positive denotes expansion and negative denotes contraction.</p><p>If no <a href="#style-value-color">&lt;color&gt;</a> term is
-present, then the computed value of the <code>tts:color</code> property applies.</p><p>If applied to a glyph area, then an <code>inset</code> token and a spread distance, if either or both are present, are ignored for purpose of presentation processing.</p><table border="1" class="ednote" summary="Editorial note: Shadow Inset"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Shadow Inset</b></td><td align="right" valign="top">2015-01-08</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define semantics of <code>inset</code> term.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>When a <a href="#style-value-length">&lt;length&gt;</a> expressed in
-cells is used in a <code>tts:textShadow</code> value,
-the cell's dimension in the block progression dimension applies.
-For example, if text shadow thickness is specified as 0.1c, the cell resolution
-is 20 by 10, and the extent of the <a href="#terms-root-container-region">root container region</a> is 640 by 480, then the
-shadow thickness will be a nominal 480 / 10 * 0.1 pixels, i.e., 4.8px,
-without taking into account rasterization effects.</p></div></div></div><div class="div2">
-<h3><a id="semantics-styling"></a>10.4 Styling Semantics</h3><p>This section defines the semantics of style resolution in terms of
-a standard processing model as follows:</p><ul><li><p><a href="#semantics-style-association"><b>10.4.1 Style Association</b></a></p></li><li><p><a href="#semantics-style-inheritance"><b>10.4.2 Style Inheritance</b></a></p></li><li><p><a href="#semantics-style-resolution-value-categories"><b>10.4.3 Style Resolution Value Categories</b></a></p></li><li><p><a href="#semantics-style-resolution-processing"><b>10.4.4 Style Resolution Processing</b></a></p></li></ul><p>Any implementation of this model is permitted provided that the
-externally observable results are consistent with the results produced
-by this model.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of style resolution employed here are based upon
-<a href="#xsl11">[XSL 1.1]</a>, § 5.</p></div><div class="div3">
-<h4><a id="semantics-style-association"></a>10.4.1 Style Association</h4><p>Style association is a sub-process of <a href="#semantics-style-resolution-processing"><b>10.4.4 Style Resolution Processing</b></a> used to determine the
-specified style set of each content and
-layout element.</p><p>Style matter may be associated with content
- and layout matter in a number of ways:</p><ul><li><p><a href="#semantics-style-association-inline">inline styling</a></p></li><li><p><a href="#semantics-style-association-referential">referential styling</a></p></li><li><p><a href="#semantics-style-association-chained-referential">chained referential styling</a></p></li></ul><p>In addition to the above, style matter may be associated with layout matter using:</p><ul><li><p><a href="#semantics-style-association-nested">nested styling</a></p></li></ul><div class="div4">
-<h5><a id="semantics-style-association-inline"></a>10.4.1.1 Inline Styling</h5><p>Style properties may be expressed in an inline manner by direct
-specification of an attribute from the TT Style Namespace on the
-affected element. When expressed in this manner, the association of
-style information is referred to as <em>inline styling</em>.</p><p>Style properties associated by inline styling are afforded a higher priority than all other
-forms of style association.</p><a id="style-association-example-1"></a><table class="example"><caption>Example – Inline Styling</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;p <span class="strong">tts:color="white"</span>&gt;White 1&nbsp;&lt;span <span class="strong">tts:color="yellow"</span>&gt;Yellow&lt;/span&gt;&nbsp;White 2&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the two text fragments <code>"White 1 "</code> and
-<code>" White 2"</code>, which are interpreted as anonymous spans, are not
-associated with a color style property; rather, they inherit their color style
-from their parent <code>p</code> element as described in <a href="#semantics-style-inheritance-content"><b>10.4.2.1 Content Style Inheritance</b></a> below.  </p></div></div><div class="div4">
-<h5><a id="semantics-style-association-referential"></a>10.4.1.2 Referential Styling</h5><p>Style properties may be expressed in an out-of-line manner and referenced by the
-affected element using the <code>style</code> attribute. When expressed in this manner,
-the association of style information is referred to as <em>referential styling</em>.</p><p>If a <code>style</code> attribute specifies multiple references, then those references are
-evaluated in the specified order, and that order applies to resolution of the value of a
-style property in the case that it is specified along multiple reference paths.</p><p>The use of referential styling is restricted to making
-reference to <code>style</code> element descendants of a <code>styling</code>
-element. It is considered an error to reference a <code>style</code>
-element that is a descendant of a <code>layout</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of referential styling encourages the reuse of style specifications while
-sacrificing locality of reference.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>A single <a href="#terms-content-element">content element</a> may be associated with style properties by a hybrid mixture of
-inline and referential styling, in which case inline styling is given priority as described above
-by <a href="#semantics-style-association-inline"><b>10.4.1.1 Inline Styling</b></a>.</p></div><a id="style-association-example-2"></a><table class="example"><caption>Example – Referential Styling</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;style <span class="strong">xml:id="s1"</span> tts:color="white"/&gt;
-&lt;style <span class="strong">xml:id="s2"</span> tts:color="yellow"/&gt;
-...
-&lt;p <span class="strong">style="s1"</span>&gt;White 1&nbsp;&lt;span <span class="strong">style="s2"</span>&gt;Yellow&lt;/span&gt;&nbsp;White 2&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the two text fragments <code>"White 1 "</code> and
-<code>" White 2"</code>, which are interpreted as anonymous spans, are not
-associated with a color style property; rather, they inherit their color style
-from their parent <code>p</code> element as described in <a href="#semantics-style-inheritance-content"><b>10.4.2.1 Content Style Inheritance</b></a> below.</p></div></div><div class="div4">
-<h5><a id="semantics-style-association-chained-referential"></a>10.4.1.3 Chained Referential Styling</h5><p>Style properties may be expressed in an out-of-line manner and may themselves reference
-other out-of-line style properties, thus creating a chain of references starting at the
-affected element. When expressed in this manner, the association of style information
-is referred to as <em>chained referential styling</em>.</p><p>If the same style property is specified in more than one referenced
-style set, then the last referenced style set applies, where the order of application starts from
-the affected element and proceeds to referenced style sets, and, in turn, to subsequent referenced style sets.</p><p>A loop in a sequence of chained style references must be considered an error.</p><p>The use of referential styling is restricted to making
-reference to <code>style</code> element descendants of a <code>styling</code>
-element. It is considered an error to reference a <code>style</code>
-element that is a descendant of a <code>layout</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of chained referential styling encourages the grouping of style specifications
-into general and specific sets, which further aids in style specification reuse.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>A single <a href="#terms-content-element">content element</a> may be associated with style properties by a hybrid mixture of
-inline, referential styling, and chained referential styling, in which case inline styling is
-given priority as described above by <a href="#semantics-style-association-inline"><b>10.4.1.1 Inline Styling</b></a>.</p></div><a id="style-association-example-3"></a><table class="example"><caption>Example – Chained Referential Styling</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;style <span class="strong">xml:id="s1"</span> tts:color="white" tts:fontFamily="monospaceSerif"/&gt;
-&lt;style <span class="strong">xml:id="s2"</span> <span class="strong">style="s1"</span> tts:color="yellow"/&gt;
-...
-&lt;p <span class="strong">style="s1"</span>&gt;White Monospace&lt;/p&gt;
-&lt;p <span class="strong">style="s2"</span>&gt;Yellow Monospace&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table></div><div class="div4">
-<h5><a id="semantics-style-association-nested"></a>10.4.1.4 Nested Styling</h5><p>Style properties may be expressed in a nested manner by direct specification of one or
-more <code>style</code> element children of the affected element.
-When expressed in this manner, the association of style information
-is referred to as <em>nested styling</em>.</p><p>Style properties associated by nested styling are afforded a lower priority than inline
-styling but with higher priority than referential styling.</p><a id="style-association-example-4"></a><table class="example"><caption>Example – Nested Styling</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region xml:id="r1"&gt;
-  <span class="strong">&lt;style tts:extent="128px 66px"/&gt;</span>
-  <span class="strong">&lt;style tts:origin="0px 0px"/&gt;</span>
-  <span class="strong">&lt;style tts:displayAlign="center"/&gt;</span>
-&lt;/region&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In this version of this specification, nested styling applies only
-to the <code>region</code> element.</p></div></div></div><div class="div3">
-<h4><a id="semantics-style-inheritance"></a>10.4.2 Style Inheritance</h4><p>Style inheritance is a sub-process of <a href="#semantics-style-resolution-processing"><b>10.4.4 Style Resolution Processing</b></a> used to determine the
-specified style set of each content and
-layout element.</p><p>Styles are further propagated to content matter
-using:
-</p><ul><li><p><a href="#semantics-style-inheritance-content">content style inheritance</a></p></li><li><p><a href="#semantics-style-inheritance-region">region style inheritance</a></p></li><li><p><a href="#semantics-style-inheritance-root">root style inheritance</a></p></li></ul><p>For the purpose of determining inherited styles, the element hierarchy of
-an intermediate synchronic document form of a <a href="#terms-document-instance">document instance</a> must be used, where
-such intermediate forms are defined by <a href="#semantics-region-layout-step-1"><b>11.3.1.3 Intermediate Synchronic Document Construction</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The intermediate synchronic document form is utilized rather than
-the original form in order to facilitate region inheritance
-processing.</p></div><div class="div4">
-<h5><a id="semantics-style-inheritance-content"></a>10.4.2.1 Content Style Inheritance</h5><p>Style properties are inherited from ancestor <a href="#terms-content-element">content elements</a>
-within an intermediate synchronic document
-if a style property is not associated with a <a href="#terms-content-element">content element</a> (or
-an anonymous span) and the style property is designated as
-inheritable.</p><p>If a style property is determined to require inheritance, then the inherited value must
-be the value of the same named style property in the computed
-style set of the
-element's nearest ancestor element that defines the property
-within the applicable intermediate synchronic document.</p><a id="style-inheritance-example-2"></a><table class="example"><caption>Example – Content Style Inheritance</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;p <span class="strong">tts:fontFamily="monospaceSansSerif"</span>&gt;
-  &lt;span tts:color="yellow"&gt;Yellow Monospace&lt;/span&gt;
-&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the <code>span</code> element that encloses the character items
-<code>Yellow Monospace</code> is not associated with a <code>tts:fontFamily</code> style
-property and this property is inheritable; therefore, the value of the
-<code>tts:fontFamily</code> style
-is inherited from the computed style
-set of the ancestor <code>p</code> element,
-and is added to the
-specified
-style
-set of the <code>span</code> element.</p></div></div><div class="div4">
-<h5><a id="semantics-style-inheritance-region"></a>10.4.2.2 Region Style Inheritance</h5><p>Style properties are inherited from a <a href="#layout-vocabulary-region">region</a> element in the following case:</p><ol class="enumar"><li><p>if an inheritable style property <em>P</em> is not associated with
-a <a href="#terms-content-element">content element</a>
-or an anonymous span <em>E</em>, and</p></li><li><p>if that style property <em>P</em> is in the computed style
-set of region <em>R</em>, and</p></li><li><p>if that element <em>E</em> is flowed into (presented within) region
-<em>R</em>.</p></li></ol><a id="style-inheritance-example-3"></a><table class="example"><caption>Example – Region Style Inheritance</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region <span class="strong">xml:id="r1"</span>&gt;
-&nbsp;&nbsp;&lt;style tts:color="yellow"/&gt;
-&nbsp;&nbsp;&lt;style tts:fontFamily="monospaceSerif"/&gt;
-&lt;/region&gt;
-...
-&lt;p <span class="strong">region="r1"</span>&gt;Yellow Monospace&lt;/p&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the anonymous span that encloses the character
-items <code>Yellow Monospace</code> effectively inherits the <code>tts:color</code>
-and <code>tts:fontFamily</code> styles specified on the <code>region</code>
-element into which the <code>p</code> element is flowed (presented).</p></div></div><div class="div4">
-<h5><a id="semantics-style-inheritance-root"></a>10.4.2.3 Root Style Inheritance</h5><p>Style properties are inherited from the root <a href="#document-structure-vocabulary-tt">tt</a> element in the following case:</p><ol class="enumar"><li><p>if an inheritable style property <em>P</em> is not associated with
-a <a href="#layout-vocabular-region"><code>region</code></a> element, and</p></li><li><p>if that
-style property <em>P</em> is in the computed style
-set of the root <a href="#document-structure-vocabulary-tt">tt</a> element.</p></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>Root style inheritance provides a mechanism by means of which <code>region</code> elements
-can inherit a common style rather than repeating the specification of the style on each
-<code>region</code> element.</p></div><a id="style-inheritance-example-4"></a><table class="example"><caption>Example – Root Style Inheritance</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt <span class="strong">tts:color="yellow"</span>&gt;
-...
-&lt;region xml:id="r1" <span class="strong">tts:fontFamily="monospaceSerif"</span>/&gt;
-...
-&lt;p region="r1"&gt;Yellow Monospace&lt;/p&gt;
-...
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the <code>region</code> element inherits the
-<code>tts:color</code> style specified on the <code>tt</code> element, which,
-along with the <code>tts:fontFamily</code> style specified on the <code>region</code>
-element, are inherited by <code>p</code> element when selected into the region.</p></div></div></div><div class="div3">
-<h4><a id="semantics-style-resolution-value-categories"></a>10.4.3 Style Resolution Value Categories</h4><p>During style resolution, layout, and presentation processing,
-three categories of style property values are distinguished as
-follows:</p><ul><li><p><a href="#semantics-style-resolved-value-category-specified">specified values</a></p></li><li><p><a href="#semantics-style-resolved-value-category-computed">computed values</a></p></li><li><p><a href="#semantics-style-resolved-value-category-actual">actual values</a></p></li></ul><div class="div4">
-<h5><a id="semantics-style-resolved-value-category-specified"></a>10.4.3.1 Specified Values</h5><p>Values of style properties that are associated with or inherited
-by an element or anonymous span are referred to as <em>specified values</em>. The
-set of all specified style properties of a given element is referred to
-as the <em>specified style set</em> of that element.</p></div><div class="div4">
-<h5><a id="semantics-style-resolved-value-category-computed"></a>10.4.3.2 Computed Values</h5><p>When style properties are specified using relative value expressions,
-such as a named color, a relative unit (e.g., cell), or a percentage, then
-they need to be further resolved into absolute units, such as an RGB triple,
-pixels, etc.</p><p>During the style resolution process, all specified style values are
-reinterpreted (or recalculated) in absolute terms, and then recorded as
-<em>computed values</em>. The
-set of all computed style properties of a given element is referred to
-as the <em>computed style set</em> of that element.</p><p>When a style value is inherited, either explicitly or implicitly, it
-is the computed value of the style that is inherited from an ancestor
-element. This is required since the resolution of certain relative units,
-such as percentage, require evaluating the expression in the immediate
-(local) context of reference, and not in a distant (remote) context of
-reference where the related (resolving) expression is not available.</p></div><div class="div4">
-<h5><a id="semantics-style-resolved-value-category-actual"></a>10.4.3.3 Actual Values</h5><p>During the actual presentation process, other transformations occur
-that map some value expressions to concrete, physical values. For example,
-the colors of computed style values are further subjected to closest color
-approximation and gamma correction
-during the display process. In addition, length value expressions that use
-pixels in computed style values are considered to express logical rather than
-physical (device) pixels. Consequently, these logical pixels are subject to
-being further transformed or mapped to physical (device) pixels during
-presentation.</p><p>The final values that result from the logical to device mapping
-process are referred to as <em>actual values</em>.  The set of all
-actual style properties of a given element is referred to as the
-<em>actual style set</em> of that element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>More than one set of actual values may be produced during the
-process of presentation. For example, a TTML <a href="#terms-presentation-processor">presentation processor</a>
-device may output an RGBA component video signal which is then
-further transformed by an NTSC or PAL television to produce a final
-image. In this case, both color and dimensions may further be modified
-prior to presentation.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>In general, a TTML <a href="#terms-presentation-processor">presentation processor</a> will not have access
-to actual style set values; as a consequence, no further use or reference
-to actual values is made below when formally describing the style
-resolution process.</p></div></div></div><div class="div3">
-<h4><a id="semantics-style-resolution-processing"></a>10.4.4 Style Resolution Processing</h4><p>The process of style resolution is defined herein as the procedure
-(and results thereof) for resolving (determining) the computed values
-of all style properties that apply to content and layout elements:</p><ul><li><p><a href="#semantics-style-resolution-processing-definitions"><b>10.4.4.1 Conceptual Definitions</b></a></p></li><li><p><a href="#semantics-style-resolution-processing-sss"><b>10.4.4.2 Specified Style Set Processing</b></a></p></li><li><p><a href="#semantics-style-resolution-processing-css"><b>10.4.4.3 Computed Style Set Processing</b></a></p></li><li><p><a href="#semantics-style-resolution-process-overall"><b>10.4.4.4 Style Resolution Process</b></a></p></li></ul><p>The process described here forms an integral sub-process of
-<a href="#semantics-region-layout"><b>11.3.1 Region Layout and Presentation</b></a>.</p><div class="div4">
-<h5><a id="semantics-style-resolution-processing-definitions"></a>10.4.4.1 Conceptual Definitions</h5><p>For the purpose of interpreting the style resolution processing
-model specified below, the following conceptual definitions apply:</p><dl><dt class="label">[style property]</dt><dd><p>a style property, <em>P</em>, is considered to consist of a
-tuple <code>[name, value]</code>, where the name of the
-property is a tuple <code>[namespace value,
-unqualified name]</code> and the value of the property is a
-tuple <code>[category, type, value expression]</code></p><a id="conceptual-definition-example-style-property"></a><table class="example"><caption>Example – conceptual style property</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-[
-  ["http://www.w3.org/ns/ttml#styling", "color"],
-  ["specified", <em>color</em>, "red"]
-]
-</pre></div>
-</td></tr></tbody></table><p></p></dd><dt class="label">[style (property) set]</dt><dd><p>a style (property) set consists of an unordered collection of style
-properties, where no two style properties within the set have an
-identical name, where by "identical name" is meant equality of
-namespace value of name tuple and unqualified name of name tuple;</p><p>in a specified style (property) set, the category of each style
-property is "specified"; a specified style (property) set of an
-element <em>E</em> is referred to as <em>SSS(E)</em>;</p><a id="conceptual-definition-example-specified-style-set"></a><table class="example"><caption>Example – conceptual (specified) style (property) set</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-{
-  [
-    ["http://www.w3.org/ns/ttml#styling", "backgroundColor"],
-    ["specified", <em>color</em>, 0x00FF00 ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "color"],
-    ["specified", <em>color</em>, "red" ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "fontSize"],
-    ["specified", <em>length</em>, "1c" ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "lineHeight"],
-    ["specified", <em>length</em>, "117%" ]
-  ]
-}
-</pre></div>
-</td></tr></tbody></table><p>in a computed style (property) set, the category of each style
-property is either "specified" or "computed"; a computed style (property) set of an element
-<em>E</em> is referred to as <em>CSS(E)</em>;</p><a id="conceptual-definition-example-computed-style-set"></a><table class="example"><caption>Example – conceptual (computed) style (property) set</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-{
-  [
-    ["http://www.w3.org/ns/ttml#styling", "backgroundColor"],
-    ["specified", <em>color</em>, 0x00FF00 ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "color"],
-    ["computed", <em>color</em>, 0xFF0000 ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "fontSize"],
-    ["computed", <em>length</em>, "24px" ]
-  ],
-  [
-    ["http://www.w3.org/ns/ttml#styling", "lineHeight"],
-    ["computed", <em>length</em>, "28px" ]
-  ]
-}
-</pre></div>
-</td></tr></tbody></table><p></p></dd><dt class="label">[style (property) merging]</dt><dd><p>a style property <em>P<sub>new</sub></em> is merged into a
-style (property) set, <em>SS</em>, as follows: if a style property
-<em>P<sub>old</sub></em> is already present in <em>SS</em>
-where the name of <em>P<sub>new</sub></em> is identical to the
-name of <em>P<sub>old</sub></em>, then replace
-<em>P<sub>old</sub></em> in <em>SS</em> with
-<em>P<sub>new</sub></em>; otherwise, add
-<em>P<sub>new</sub></em> to <em>SS</em>;</p></dd><dt class="label">[style (property) set merging]</dt><dd><p>a style (property) set <em>SS<sub>new</sub></em> is merged into
-an existing style (property) set <em>SS<sub>old</sub></em> as
-follows: for each style property <em>P<sub>new</sub></em> in
-<em>SS<sub>new</sub></em>, merge <em>P<sub>new</sub></em> into
-<em>SS<sub>old</sub></em>;</p></dd></dl></div><div class="div4">
-<h5><a id="semantics-style-resolution-processing-sss"></a>10.4.4.2 Specified Style Set Processing</h5><p>The specified style set <em>SSS</em> of an element or
-anonymous span <em>E</em>,
-<em>SSS(E)</em>, is determined according to the following ordered
-rules:</p><ol class="enumar"><li><p><span class="strong">[initialization]</span> initialize
-the specified style set <em>SSS</em> of <em>E</em> to the
-empty set;</p></li><li><p><span class="strong">[referential and chained referential
-styling]</span> for each <code>style</code> element <em>S<sub>REF</sub></em>
-referenced by a <code>style</code> attribute specified on
-<em>E</em>, and in the order specified in the <code>style</code>
-attribute, then, if <em>S<sub>REF</sub></em> is a descendant
-of a <code>styling</code> element,
-merge the specified style set of
-<em>S<sub>REF</sub></em>, <em>SSS(S<sub>REF</sub>)</em>, into
-the specified style set of <em>E</em>,
-<em>SSS(E)</em>;</p></li><li><p><span class="strong">[nested styling]</span> for each
-nested <code>style</code> element child <em>S<sub>NEST</sub></em> of
-<em>E</em>, and in the specified order of child elements, merge
-the specified style set of <em>S<sub>NEST</sub></em>,
-<em>SSS(S<sub>NEST</sub>)</em>, into the specified style set of
-<em>E</em>, <em>SSS(E)</em>;</p></li><li><p><span class="strong">[inline styling]</span> for each
-style property <em>P</em> expressed as a specified styling
-attribute of <em>E</em>,
-merge <em>P</em> into the specified style
-set of <em>E</em>, <em>SSS(E)</em>;</p></li><li><p><span class="strong">[animation styling]</span> if the
-element type of <em>E</em> is not the animation element type
-<code>set</code>, then for each
-immediate animation (<code>set</code>) element child <em>A</em> of element <em>E</em>,
-merge the specified style set of <em>A</em>,
-<em>SSS(A)</em>, into the specified style set of <em>E</em>, <em>SSS(E)</em>;</p></li><li><p><span class="strong">[implicit inheritance and initial value fallback]</span> if the
-element type of <em>E</em> is not animation element type <code>animate</code> or <code>set</code>
-and is not styling element type <code>style</code>,
-then for each style property
-<em>P</em> in the set of style properties defined
-above in <a href="#styling-attribute-vocabulary"><b>10.2 Styling Attribute Vocabulary</b></a>, perform the
-following ordered sub-steps:</p><ol class="enumla"><li><p>if <em>P</em> is present in the specified
-style set of <em>E</em>, <em>SSS(E)</em>, then continue to the
-next style property;</p></li><li><p>if <em>P</em> is defined to be inheritable and <em>E</em> is
-not the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element, then perform the following:</p><ul><li><p>set <em>P′</em> to the result of
-looking up the value of <em>P</em> in the computed style set of
-the nearest ancestor element of <em>E</em>, <em>NEAREST-ANCESTOR(E)</em>, such that
-<em>CSS(NEAREST-ANCESTOR(E))</em> contains a definition of <em>P</em>;</p></li></ul></li><li><p>otherwise (<em>P</em> is not inheritable or <em>E</em> is
-the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element), perform the following:</p><ul><li><p>set <em>P′</em> to the initial value of
-property <em>P</em>, where the initial value of a property is
-determined as follows:</p><ol class="enumlr"><li><p>if an <a href="#styling-vocabulary-initial"><code>initial</code></a>
-element defines the initial value for <em>P</em>, then use that value;</p></li><li><p>otherwise, use the initial value specified by the property definition of <em>P</em> found above
-in <a href="#styling-attribute-vocabulary"><b>10.2 Styling Attribute Vocabulary</b></a>;</p></li></ol></li></ul></li><li><p>if the value of <em>P′</em> is not undefined, then merge
-<em>P′</em> into the specified style set of <em>E</em>,
-<em>SSS(E)</em>.</p></li></ol></li></ol></div><div class="div4">
-<h5><a id="semantics-style-resolution-processing-css"></a>10.4.4.3 Computed Style Set Processing</h5><p>The computed style set <em>CSS</em> of an element or
-anonymous span <em>E</em>,
-<em>CSS(E)</em>, is determined according to the following ordered
-rules:</p><ol class="enumar"><li><p><span class="strong">[resolve specified styles]</span>
-determine (obtain) the specified style set <em>SSS</em> of
-<em>E</em>, namely, <em>SSS(E)</em>, in accordance with
-<a href="#semantics-style-resolution-processing-sss"><b>10.4.4.2 Specified Style Set Processing</b></a>;</p></li><li><p><span class="strong">[initialization]</span>
-initialize <em>CSS(E)</em> to a (deep) copy of
-<em>SSS(E)</em>;</p></li><li><p><span class="strong">[filter]</span> if
-<em>E</em> is an <code>animate</code>, <code>set</code>, or <code>style</code> element, then return
-<em>CSS(E)</em> as the resulting computed style set without
-further resolution; otherwise, continue with the next rule;</p></li><li><p><span class="strong">[relative value resolution]</span> for each
-style property <em>P</em> in <em>CSS(E)</em>, where the value
-type of <em>P</em> is relative, perform the following ordered
-sub-steps:</p><ol class="enumla"><li><p>replace the relative value of <em>P</em> with an
-equivalent, non-relative (computed) value;</p></li><li><p>set the category of <em>P</em> to "computed";</p></li></ol></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>As a result of the filtering rule above, the computed style set of
-an <code>animate</code>, <code>set</code>, or <code>style</code> element includes only specified values, in which case
-relative value expressions remain relative; consequently, the
-resolution of relative value expressions (that may be assigned by
-means of referential style association) always takes place in the
-context of a layout or <a href="#terms-content-element">content element</a> which has a presentation
-context, and not in the non-presentation, declaration context
-of an <code>animate</code>, <code>set</code>, or referable <code>style</code> element.</p></div></div><div class="div4">
-<h5><a id="semantics-style-resolution-process-overall"></a>10.4.4.4 Style Resolution Process</h5><p>The top-level style resolution process is defined as follows: using
-a preorder traversal of each element and <em>anonymous span</em>,
-<em>E</em>, of an intermediate synchronic document,
-<em>DOC<sub>inter</sub></em>, perform the following ordered
-sub-steps:</p><ol class="enumar"><li><p><span class="strong">[filter]</span> if <em>E</em>
-is not one of the following, then continue to the next element in the preorder traversal, i.e.,
-do not perform the subsequent step below on <em>E</em>:</p><ul><li><p><a href="#document-structure-vocabulary-tt"><code>tt</code></a></p></li><li><p><a href="#styling-vocabulary-style"><code>style</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li><li><p><a href="#animation-vocabulary-animate"><code>animate</code></a></p></li><li><p><a href="#animation-vocabulary-set"><code>set</code></a></p></li><li><p><em>anonymous span</em></p></li></ul></li><li><p> <span class="strong">[resolve computed styles]</span>
-determine (obtain) the computed style set <em>CSS</em> of
-<em>E</em>, namely, <em>CSS(E)</em>, in accordance with
-<a href="#semantics-style-resolution-processing-css"><b>10.4.4.3 Computed Style Set Processing</b></a>.</p></li></ol></div></div><div class="div3">
-<h4><a id="semantics-style-automatic-measure-calculation"></a>10.4.5 Automatic Measure Calculation</h4><table border="1" class="ednote" summary="Editorial note: Automatic Measures"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Automatic Measures</b></td><td align="right" valign="top">2014-11-30</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define semantics for resolving the <code>auto</code> value as used with a  <a href="#style-value-measure">&lt;measure&gt;</a> expression,
-the definition of which should be consistent with <a href="#css3-box">[CSS Box Model]</a>, § 15.</td></tr></table></div></div></div><div class="div1">
-<h2><a id="layout"></a>11 Layout</h2><p>This section specifies the <em>layout</em> matter of the core
-vocabulary catalog, where
-layout is to be understood as a separable layer of information that applies to
-content and that denotes authorial intentions about the presentation of
-that content.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The two layers of layout and style matter are considered to be independently
-separable. Layout matter specifies one or more spaces or areas into
-which content is intended to be presented, while style matter specifies the manner in
-which presentation occurs within the layout.</p><p>In certain cases, a content author may choose to embed (inline) style matter directly
-into layout or content matter. In such cases, an alternative 
-exists – use of referential styling –
-in which the style
-matter is not embedded (inlined).</p></div><div class="div2">
-<h3><a id="layout-element-vocabulary"></a>11.1 Layout Element Vocabulary</h3><p>The following elements specify the structure and principal layout aspects of a
-<a href="#terms-document-instance">document instance</a>:</p><ul><li><p><a href="#layout-vocabulary-layout"><b>11.1.1 layout</b></a></p></li><li><p><a href="#layout-vocabulary-region"><b>11.1.2 region</b></a></p></li></ul><div class="div3">
-<h4><a id="layout-vocabulary-layout"></a>11.1.1 layout</h4><p>The <code>layout</code> element is a container element used to group
-out-of-line layout matter, including metadata that applies to layout matter.</p><p>The <code>layout</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by
-zero or more <code>region</code> elements.</p><a id="elt-syntax-layout"></a><table class="syntax"><caption>XML Representation – Element Information Item: layout</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;layout
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#layout-vocabulary-region">region</a>*
-&lt;/layout&gt;
-</pre></div>
-</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
-<code>layout</code> element, the implied time interval of this element is
-defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div><div class="div3">
-<h4><a id="layout-vocabulary-region"></a>11.1.2 region</h4><p>The <code>region</code> element is used to define a rectangular space or area into which content is
-to be flowed for the purpose of presentation.</p><p>A <code>region</code> element may appear as either (1) a child of a
-<a href="#layout-vocabulary-layout">layout</a> element or (2) a child of block level
-<a href="#terms-content-element">content element</a>, specifically, of elements
-in the <a href="#element-vocab-group-block">Block.class</a> element group.
-In the former case, the region is referred to as an <a href="#terms-out-of-line-region">out-of-line region</a>, while in the latter
-case, it is referred to as an <a href="#terms-inline-region">inline region</a>.</p><p>In addition, and in accordance with
-<a href="#semantics-style-inheritance-region"><b>10.4.2.2 Region Style Inheritance</b></a>, 
-the <code>region</code> element may be used to specify inheritable style properties to be
-inherited by content that is flowed into it.</p><p>The <code>region</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more
-elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
-followed by
-zero or more <code>style</code> elements.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
-element group applies semantically to the <code>region</code> element and its descendants as a whole.
-Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
-element group apply semantically to the <code>region</code> element.
-Any <code>style</code> child element must be considered a local style
-definition that applies only to the containing <code>region</code>
-element, i.e., does not apply for resolving referential styling (but does apply for region
-style inheritance).</p><a id="elt-syntax-region"></a><table class="syntax"><caption>XML Representation – Element Information Item: region</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;region
-  <a href="#animation-attribute-animate">animate</a> = IDREFS
-  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
-  <a href="#metadata-attribute-role">ttm:role</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, <a href="#styling-vocabulary-style">style</a>*
-&lt;/region&gt;
-</pre></div>
-</td></tr></tbody></table><p>An <a href="#terms-out-of-line-region">out-of-line</a> <code>region</code> element
-must specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute.</p><p>An <a href="#terms-out-of-line-region">out-of-line</a> <code>region</code> element may specify one or more of the timing attributes:
-<code>begin</code>, <code>end</code>, <code>dur</code>. An <a href="#terms-inline-region">inline</a> <code>region</code> element must not
-specifiy a timing attribute, and, if specified, must be ignored for the purpose
-of presentation processing.</p><p>If <code>begin</code> and (or) <code>end</code> attributes are specified on an out-of-line
-<code>region</code> element, then they specify the beginning and (or) ending points
-of a time interval during which the region is eligible for activation and with
-respect to which animation child elements of the region are timed.
-If specified, these begin and end points are relative to the time
-interval of the nearest ancestor element associated with a time
-interval, irregardless of whether that interval is explicit or implied.
-The nearest ancestor element of an out-of-line <code>region</code> element that is associated
-with a time interval is the <code>layout</code> element.
-If a <code>dur</code> attribute is specified on an out-of-line <code>region</code> element, then it
-specifies the simple duration of the region.</p><p>The active time interval of an <a href="#terms-inline-region">inline</a> <code>region</code> element is the
-active time interval of its parent <a href="#terms-content-element">content element</a>.</p><p>For the purpose of determining the semantics of presentation processing, a
-region that is temporally inactive must not produce any visible marks when
-presented on a visual medium.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>An <a href="#terms-out-of-line-region">out-of-line</a> <code>region</code> element may be associated with a time interval for two
-purposes: (1) in order to temporally bound the presentation of the region and
-its content, and (2) to provide a temporal context in which animations of region
-styles may be effected.</p><p>For example, an author may wish to specify an <a href="#terms-out-of-line-region">out-of-line</a> <code>region</code> element that is otherwise empty, but
-may have a visible background color to be presented starting at some time and
-continuing over the region's duration.  The simple duration of the region serves
-additionally to scope the presentation effects of content that is targeted to the
-region. An author may also wish to move a region within the <a href="#terms-root-container-region">root container region</a>
-or change a region's background color by means of animation effects. In
-both of these cases, it is necessary to posit an active time interval for a
-region.</p><p>In contrast to <a href="#terms-out-of-line-region">out-of-line regions</a>, <a href="#terms-inline-region">inline regions</a> are specifically bound to
-the temporal context of their parent <a href="#terms-content-element">content elements</a>,
-and, as such, do not require (or admit) the specification of independent timing.</p></div><p>If no <code>timeContainer</code> attribute is specified on
-a <code>region</code> element, then it must be interpreted as having
-<em>parallel</em> time containment semantics.</p><p>If both <a href="#style-attribute-origin"><code>tts:origin</code></a> and <a href="#style-attribute-position"><code>tts:position</code></a> attributes are present
-on a <code>region</code> element, then the <a href="#style-attribute-origin"><code>tts:origin</code></a> must be ignored for the purpose of presentation processing.
-If neither <a href="#style-attribute-origin"><code>tts:origin</code></a> nor <a href="#style-attribute-position"><code>tts:position</code></a> attribute is present and
-if the computed value of the the <a href="#parameter-attribute-version"><code>ttp:version</code></a> attribute on the root <code>tt</code> element is two (2) or greater, then
-the semantics of the initial value of the <a href="#style-attribute-position"><code>tts:position</code></a> attribute apply for the purpose of presentation processing; otherwise, the semantics of the initial value of the <a href="#style-attribute-origin"><code>tts:origin</code></a> attribute apply.</p><p>If a <a href="#metadata-attribute-role"><code>ttm:role</code></a> attribute is
-specified on a <code>region</code> element, then it must adhere to the
-value syntax defined by <a href="#metadata-attribute-role-syntax"><b>Syntax Representation – ttm:role</b></a>, and where the roles identified
-by this attribute express the semantic roles of the region
-independently from the semantic roles of any content targeted to
-(associated with) the region.</p></div></div><div class="div2">
-<h3><a id="layout-attribute-vocabulary"></a>11.2 Layout Attribute Vocabulary</h3><p>This section defines the <a href="#layout-attribute-region"><b>11.2.1 region</b></a> attribute used with <a href="#terms-content-element">content elements</a>.</p><div class="div3">
-<h4><a id="layout-attribute-region"></a>11.2.1 region</h4><p>The <code>region</code> attribute is used to reference a <code>region</code>
-element which defines a space or area into which a <a href="#terms-content-element">content element</a> is intended to be flowed.</p><p>If specified, the value of a <code>region</code> attribute must
-adhere to the <code>IDREF</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§ 3.3.9, and, furthermore, this IDREF must reference a <code>region</code> element
-which has a <code>layout</code> element as an ancestor.</p><p>The <code>region</code> attribute may be specified by an instance of the following
-element types:</p><ul><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#semantics-region-layout"><b>11.3.1 Region Layout and Presentation</b></a> below for further information on content
-flow in a region.</p></div></div></div><div class="div2">
-<h3><a id="semantics-layout"></a>11.3 Layout Semantics</h3><div class="issue"><p class="prefix"><a id="issue-365"></a><b>Issue (issue-365):</b></p><p class="prefix"><b>HTML Mapping</b></p><p><b>Source</b>: <a href="https://www.w3.org/AudioVideo/TT/tracker/issues/365">https://www.w3.org/AudioVideo/TT/tracker/issues/365</a></p><p>Define HTML5 mapping while separating ISD generation from follow-on mappings.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><div class="div3">
-<h4><a id="semantics-region-layout"></a>11.3.1 Region Layout and Presentation</h4><p>This section defines the semantics of region layout and
-presentation in terms of a standard processing model as
-follows:</p><ul><li><p><a href="#semantics-default-region"><b>11.3.1.1 Default Region</b></a></p></li><li><p><a href="#semantics-inline-regions"><b>11.3.1.2 Inline Regions</b></a></p></li><li><p><a href="#semantics-region-layout-step-1"><b>11.3.1.3 Intermediate Synchronic Document Construction</b></a></p></li><li><p><a href="#semantics-region-layout-step-2"><b>11.3.1.4 Synchronic Flow Processing</b></a></p></li><li><p><a href="#semantics-region-layout-example"><b>11.3.1.5 Elaborated Example (Non-Normative)</b></a></p></li></ul><p>Any
-implementation is permitted provided that the externally observable
-results are consistent with the results produced by this model.
-</p><div class="div4">
-<h5><a id="semantics-default-region"></a>11.3.1.1 Default Region</h5><p>If a <a href="#terms-document-instance">document instance</a> does not specify an
-<a href="#terms-out-of-line-region">out-of-line region</a>,
-then a <em>default region</em> is implied with the following characteristics:</p><ul><li><p>the identity of the default region is considered to be an anonymous <a href="#terms-out-of-line-region">out-of-line region</a>;</p></li><li><p>the extent of the default region is the same as the extent of the <a href="#terms-root-container-region">root container region</a>;</p></li><li><p>the temporal interval of the default region is the same as the interval defined by the <a href="#terms-root-temporal-extent">root temporal extent</a>;</p></li></ul><p>Furthermore, if no
-<a href="#terms-out-of-line-region">out-of-line region</a> is specified, then the
-<a href="#layout-attribute-region"><code>region</code></a> attribute must
-not be specified on any <a href="#terms-content-element">content element</a> in the <a href="#terms-document-instance">document instance</a>.</p><p>If a default region is implied for a given <a href="#terms-document-instance">document instance</a>, then
-the <a href="#document-structure-vocabulary-body"><code>body</code></a> element
-is implicitly targeted to (associated with) the default region.</p><p>When implying a default region, the <a href="#terms-document-instance">document instance</a> is to be
-treated as if a <a href="#layout-vocabulary-region"><code>region</code></a> element and its
-parent <a href="#layout-vocabulary-layout"><code>layout</code></a>
-element were specified in a <a href="#document-structure-vocabulary-head"><code>head</code></a>
-element, and a matching <a href="#layout-attribute-region"><code>region</code></a> attribute were
-specified on the <a href="#document-structure-vocabulary-body"><code>body</code></a> element
-as shown in the following example:</p><a id="semantics-default-region-example"></a><table class="example"><caption>Example – Implied Default Region</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head&gt;
-    <span class="strong">&lt;layout&gt;
-      &lt;region xml:id="anonymous"/&gt;
-    &lt;/layout&gt;</span>
-  &lt;/head&gt;
-  &lt;body <span class="strong">region="anonymous"</span>/&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, a default <code>region</code> element and <code>region</code>
-attribute are implied. In addition, a <code>layout</code> container element is implied for
-the implied <code>region</code> element.</p></div></div><div class="div4">
-<h5><a id="semantics-inline-regions"></a>11.3.1.2 Inline Regions</h5><p>An <a href="#terms-inline-region">inline region</a> is a syntactic mechanism for specifying a
-<a href="#terms-region">region</a> in a way that minimizes the syntactic distance between a region
-specification and the content that references that region. Semantically, each
-<a href="#terms-inline-region">inline region</a> is equivalent to specifying a unique
-<a href="#terms-out-of-line-region">out-of-line region</a> referenced implicitly only by the
-<a href="#terms-content-element">content element</a> in whose context the
-<a href="#terms-inline-region">inline region</a> is specified (or implied).</p><p>An <a href="#terms-inline-region">inline region</a> is declared in one of two ways:
-(1) by specifying a <a href="#style-attribute-extent"><code>tts:extent</code></a> or
-<a href="#style-attribute-origin"><code>tts:origin</code></a> style attribute on
-a <a href="#terms-content-element">content element</a>
-in the <a href="#element-vocab-group-block">Block.class</a> element group, or
-(2) by specifying an explicit  <a href="#layout-vocabulary-region"><code>region</code></a> element
-child of a <a href="#terms-content-element">content element</a>
-in the <a href="#element-vocab-group-block">Block.class</a> element group. The
-former is referred to as an <em>implied inline region specification</em>,
-the latter as an <em>explicit inline region specification</em>; furthermore, the former is considered
-to be a syntactic shorthand for the latter, and is processed by converting it into the latter as
-described below.</p><p>Inline regions are processed in accordance with the procedure
-<span class="strong"><a href="#procedure-process-inline-regions">[process inline regions]</a></span>, which
-entails first generating implied inline regions, and then generating out-of-line regions that correspond with implied
-or explicit inline regions. This latter procedure additionally binds content elements associated with inline regions
-to the corresponding generated out-of-line regions.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <a href="#terms-content-element">content element</a> can only be associated with a single
-<a href="#terms-region">region</a>. Consequently, if a <a href="#terms-content-element">content element</a>
-specifies a <a href="#layout-attribute-region"><code>region</code></a> attribute, then any <em>implied inline region specification</em>
-or <em>explicit inline region specification</em> is ignored. If the <a href="#terms-content-element">content element</a> does not specify a
-<a href="#layout-attribute-region"><code>region</code></a> attribute, but it includes
-both an <em>implied inline region specification</em> and an <em>explicit inline region specification</em>,
-then the former is ignored in favor of the latter.</p></div><dl><dt class="label"><a id="procedure-process-inline-regions"></a>[process inline regions]</dt><dd><ol class="enumar"><li><p>perform procedure <span class="strong"><a href="#procedure-generate-inline-regions">[generate inline regions]</a></span>;</p></li><li><p>perform procedure <span class="strong"><a href="#procedure-generate-out-of-line-regions">[generate out-of-line regions]</a></span>;</p></li></ol></dd><dt class="label"><a id="procedure-generate-inline-regions"></a>[generate inline regions]</dt><dd><p>For each <a href="#terms-content-element">content element</a> <em>B</em>
-in the <a href="#element-vocab-group-block">Block.class</a> element group,
-perform the following ordered steps:</p><ol class="enumar"><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains
-neither <a href="#style-attribute-extent"><code>tts:extent</code></a> nor
-<a href="#style-attribute-origin"><code>tts:origin</code></a> style attribute, then exit this procedure;</p></li><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains a
-<a href="#layout-attribute-region"><code>region</code></a> attribute, then exit this procedure</p></li><li><p>if the <code>[children]</code> information item property of <em>B</em> contains a
-<a href="#layout-vocabulary-region"><code>region</code></a> element, then exit this procedure;</p></li><li><p>create an empty <a href="#layout-vocabulary-region"><code>region</code></a> element <em>R</em>,
-initialized as follows:</p><ul><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains a
-<a href="#style-attribute-extent"><code>tts:extent</code></a> attribute,
-then copy that attribute to the <code>[attributes]</code> information item property of <em>R</em>;
-otherwise, add a <a href="#style-attribute-extent"><code>tts:extent</code></a> attribute with value <code>auto</code>
-to the <code>[attributes]</code> information item property of <em>R</em>;</p></li><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains a
-<a href="#style-attribute-origin"><code>tts:origin</code></a> attribute,
-then copy that attribute to the <code>[attributes]</code> information item property of <em>R</em>;
-otherwise, add a <a href="#style-attribute-origin"><code>tts:origin</code></a> attribute with value <code>auto</code>
-to the <code>[attributes]</code> information item property of <em>R</em>;</p></li></ul></li><li><p>insert <em>R</em> into the <code>[children]</code> information item property of <em>B</em>
-such that <em>R</em> immediately precedes the first <a href="#terms-content-element">content element</a>
-child of <em>B</em>, or, if none is present, then <em>R</em> is the last child element of <em>B</em>;</p></li><li><p>remove the <a href="#style-attribute-extent"><code>tts:extent</code></a> and
-<a href="#style-attribute-origin"><code>tts:origin</code></a> style attributes, if present, from the
-<code>[attributes]</code> information item property of <em>B</em>;</p></li></ol></dd><dt class="label"><a id="procedure-generate-out-of-line-regions"></a>[generate out-of-line regions]</dt><dd><p>For each <a href="#terms-content-element">content element</a> <em>B</em>
-in the <a href="#element-vocab-group-block">Block.class</a> element group,
-perform the following ordered steps:</p><ol class="enumar"><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains a
-<a href="#layout-attribute-region"><code>region</code></a> attribute, then exit this procedure</p></li><li><p>if the <code>[children]</code> information item property of <em>B</em> does not contain
-a <a href="#layout-vocabulary-region"><code>region</code></a> element <em>R</em>, then exit this procedure;</p></li><li><p>create an empty <a href="#layout-vocabulary-region"><code>region</code></a> element <em>R'&nbsp;</em>,
-initialized as follows:</p><ul><li><p>set the <code>[children]</code> information item property of <em>R'&nbsp;</em> to a deep copy of
-the <code>[children]</code> information item property of <em>R</em>;</p></li><li><p>set the <code>[attributes]</code> information item property of <em>R'&nbsp;</em> to a deep copy of
-the <code>[attributes]</code> information item property of <em>R</em>;</p></li><li><p>if the <code>[attributes]</code> information item property of <em>R'&nbsp;</em> does not include
-an <code>xml:id</code> attribute, then add an implied <code>xml:id</code> attribute with a generated value
-<em>ID</em> that is unique within the scope of the TTML <a href="#terms-document-instance">document instance</a>;
-otherwise, let <em>ID</em> be the value of the <code>xml:id</code> attribute of <em>R'&nbsp;</em>;</p></li><li><p>if present, remove the following attributes from the <code>[attributes]</code> information item property of <em>R'&nbsp;</em>:
-<code>begin</code>,
-<code>dur</code>, and
-<code>end</code>;</p></li><li><p>add a <code>begin</code> attribute to the <code>[attributes]</code> information item property of <em>R'&nbsp;</em> with
-a value equivalent to the computed begin time of <em>B</em> within the root temporal extent;</p></li><li><p>add a <code>dur</code> attribute to the <code>[attributes]</code> information item property of <em>R'&nbsp;</em> with
-a value equivalent to the computed simple duration of <em>B</em>;</p></li></ul></li><li><p>if the TTML <a href="#terms-document-instance">document instance</a> does not have a
-<a href="#document-structure-vocabulary-head"><code>head</code></a> element, then insert an empty
-<a href="#document-structure-vocabulary-head"><code>head</code></a> element as the first child of
-the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element;</p></li><li><p>if the <a href="#document-structure-vocabulary-head"><code>head</code></a> element does not have
-a <a href="#layout-vocabulary-layout"><code>layout</code></a> child element, then insert an empty
-<a href="#layout-vocabulary-layout"><code>layout</code></a> element immediately after a
-<a href="#styling-vocabulary-styling"><code>styling</code></a> element, if present, and immediately before an
-<a href="#animation-vocabulary-styling"><code>animation</code></a> element, if present, or as the last child of
-the <a href="#document-structure-vocabulary-head"><code>head</code></a> element if neither are present;</p></li><li><p>append <em>R'&nbsp;</em> to the <code>[children]</code> information item property of the
-<a href="#layout-vocabulary-layout"><code>layout</code></a> element child of the 
-<a href="#document-structure-vocabulary-head"><code>head</code></a> element;</p></li><li><p>add a <a href="#layout-attribute-region"><code>region</code></a> attribute with value <em>ID</em> to the <code>[attributes]</code> information
-item property of <em>B</em>;</p></li><li><p>remove <em>R</em> from the <code>[children]</code> information item property of <em>B</em>;</p></li></ol><div class="issue"><p class="prefix"><a id="issue-324"></a><b>Issue (issue-324):</b></p><p class="prefix"><b>Duration Restrictions</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/324">http://www.w3.org/AudioVideo/TT/tracker/issues/324</a></p><p>Handle case where use of <code>dur</code> is not permitted, e.g., when using discontinuous SMPTE time base.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div></dd></dl><p>The use of an <em>implied inline region specification</em> and the resulting generated inline region is shown by the following two example documents.</p><a id="semantics-inline-region-input-example-1-implied"></a><table class="example"><caption>Example – Implied Inline Region Specification</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head/&gt;
-  &lt;body&gt;
-    &lt;div <span class="strong">tts:extent="540px 100px" tts:origin="50px 339px"</span>&gt;
-      &lt;p&gt;Some Content&lt;/p&gt;
-    &lt;div/&gt;
-  &lt;body/&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="semantics-generated-out-of-line-region-example-1-implied"></a><table class="example"><caption>Example – Generated Inline Region</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head/&gt;
-  &lt;body&gt;
-    &lt;div&gt;
-      <span class="strong">&lt;region tts:extent="540px 100px" tts:origin="50px 339px"/&gt;</span>
-      &lt;p&gt;Some Content&lt;/p&gt;
-    &lt;div/&gt;
-  &lt;body/&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p>The use of an <em>explicit inline region specification</em> or a generated inline region that derives from
-an <em>implicit inline region specification</em>
-and the resulting generated out-of-line region is shown by the following two example documents.</p><a id="semantics-inline-region-input-example-2-explicit"></a><table class="example"><caption>Example – Explicit or Generated Inline Region Specification</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head/&gt;
-  &lt;body&gt;
-    &lt;div begin="5s" dur="10s"&gt;
-      <span class="strong">&lt;region tts:extent="540px 100px" tts:origin="50px 339px"/&gt;</span>
-      &lt;p&gt;Some Content&lt;/p&gt;
-    &lt;div/&gt;
-  &lt;body/&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p></p><a id="semantics-generated-out-of-line-region-example-2-explicit"></a><table class="example"><caption>Example – Generated Out-of-line Region</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
-  &lt;head&gt;
-    <span class="strong">&lt;layout&gt;
-      &lt;region xml:id="region3451" begin="5s" dur="10s" tts:extent="540px 100px" tts:origin="50px 339px"/&gt;
-    &lt;/layout&gt;</span>
-  &lt;/head&gt;
-  &lt;body&gt;
-    &lt;div begin="5s" dur="10s" <span class="strong">region="region3451"</span>&gt;
-      &lt;p&gt;Some Content&lt;/p&gt;
-    &lt;div/&gt;
-  &lt;body/&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table></div><div class="div4">
-<h5><a id="semantics-region-layout-step-1"></a>11.3.1.3 Intermediate Synchronic Document Construction</h5><table border="1" class="ednote" summary="Editorial note: Use Formalized ISD"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Use Formalized ISD</b></td><td align="right" valign="top">2014-09-22</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Revise in order to take into account new formalization of ISD structure and semantics (Appendix C).</td></tr></table><p>For the purposes of performing presentation processing, the active time
-duration of a <a href="#terms-document-instance">document instance</a> is divided into a sequence of time coordinates where at
-each time coordinate, some element becomes temporally active or inactive,
-then, at each such time coordinate, a <a href="#terms-document-instance">document instance</a> is mapped from its original, source
-form, <em>DOC<sub>source</sub></em> , 
-to an intermediate
-synchronic document form,
-<em>DOC<sub>inter</sub></em> , according to the
-<span class="strong"><a href="#procedure-construct-intermediate-document">[construct intermediate document]</a></span> procedure:</p><dl><dt class="label"><a id="procedure-construct-intermediate-document"></a>[construct intermediate document]</dt><dd><ol class="enumar"><li><p>perform procedure <span class="strong"><a href="#procedure-process-inline-regions">[process inline regions]</a></span>;</p></li><li><p>for each temporally active region <em>R</em>, replicate the
-sub-tree
- of <em>DOC<sub>source</sub></em>
-headed by the <code>body</code> element;</p></li><li><p>evaluating this sub-tree in a postorder traversal, prune elements if they
-are not a <a href="#terms-content-element">content element</a>, if they are temporally inactive, if they are empty,
-or if they aren't associated with region <em>R</em> according to the
-<span class="strong"><a href="procedure-associate-region">[associate region]</a></span> procedure;</p></li><li><p>if the pruned sub-tree is non-empty, then reparent it to the <em>R</em>
-element;</p></li><li><p>finally, after completing the above steps, prune the original <code>body</code>
-element from the intermediate document, then prune all <code>region</code>,
-<code>begin</code>, <code>end</code>, and <code>dur</code> attributes, which are no
-longer semantically relevant;</p></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>In this section, the term <em>prune</em>, when used in reference to
-an element, means that the element is to be removed from its parent's children,
-which, in turn, implies that the descendants of the pruned element will no longer
-be descendants of the element's parent. When <em>prune</em> is used in
-reference to an attribute, it means that attribute is to be removed from its
-associated (owning) element node.</p></div></dd><dt class="label"><a id="procedure-associate-region"></a>[associate region]</dt><dd><p></p><div class="issue"><p class="prefix"><a id="issue-341"></a><b>Issue (issue-341):</b></p><p class="prefix"><b>Multiple Descendant Region Ambiguitty</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/341">http://www.w3.org/AudioVideo/TT/tracker/issues/341</a></p><p>Refine step (3) to resolve ambiguity when multiple regions are referenced by descendants.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><table border="1" class="ednote" summary="Editorial note: Inline Region Association"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Inline Region Association</b></td><td align="right" valign="top">2013-08-28</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define inline region association.</td></tr></table><p>A <a href="#terms-content-element">content element</a> is associated with a region according
-to the following ordered rules, where the first rule satisfied
-is used and remaining rules are skipped:</p><ol class="enumar"><li><p>if the element specifies a <a href="#layout-attribute-region"><code>region</code></a> attribute,
-then the element is associated with the region referenced by that
-attribute;</p></li><li><p>if some ancestor of that element specifies a <a href="#layout-attribute-region"><code>region</code></a> attribute,
-then the element is associated with the region referenced by the most
-immediate ancestor that specifies this attribute;</p></li><li><p> if the element contains a descendant element that
-specifies a <a href="#layout-attribute-region"><code>region</code></a> attribute,
-then the element is associated with the region referenced by that
-attribute;</p></li><li><p>if a default region was implied (due to the absence of any
-<a href="#layout-vocabulary-region"><code>region</code></a> element),
-then the element is associated with the default region;</p></li><li><p>the element is not associated with any region.</p></li></ol></dd></dl><p>The result of performing the processing described above will be a sequence of
-<em>N</em> intermediate  synchronic
-<a href="#terms-document-instance">document instances</a>,
-<em>DOC<sub><span>inter<sub>0</sub></span></sub></em> …
-<em>DOC<sub><span>inter<sub>N−1</sub></span></sub></em>.</p><div class="note" id="semantics-smooth-scrolling-recommendation"><p class="prefix"><b>Note:</b></p><p>Where an implementation is able to detect significant similarity between two
-adjacent synchronic <a href="#terms-document-instance">document instances</a>,
-<em>DOC<sub><span>inter<sub>N</sub></span></sub></em>
-<em>DOC<sub><span>inter<sub>N−1</sub></span></sub></em>,
-then it is preferred that the implementation make the transition between
-presenting the two instances as smooth as possible, e.g., as described
-by <a href="#cea608e">[CEA-608-E]</a>, § C.3, and <a href="#ccreq">[CC-DECODER-REQ]</a>.</p></div></div><div class="div4">
-<h5><a id="semantics-region-layout-step-2"></a>11.3.1.4 Synchronic Flow Processing</h5><p>Subsequent to performing a temporal (synchronic) slice and subsequent
-remapping of regionally selected content hierarchy, the resulting intermediate
-synchronic document is subjected to a flow transformation step that produces 
-a rooted flow object tree represented as an XSL FO document instance as defined by <a href="#xsl11">[XSL 1.1]</a>,
-and semantically extended by TTML specific style properties that have no XSL
-FO counterpart.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this section, the use of XSL FO is intended to be conceptual only, employed
-solely for the purpose of defining the normative presentation semantics of
-TTML. An actual implementation of this algorithm is not required to create or process
-XSL-FO representations. In particular, it is possible to implement these semantics
-using alternative presentation models, such as Cascading Style Sheets (CSS).</p></div><p>Each intermediate synchronic document produced by <a href="#semantics-region-layout-step-1"><b>11.3.1.3 Intermediate Synchronic Document Construction</b></a> is mapped 
-to an XSL FO document instance, <em>F</em>, as follows:</p><ol class="enumar"><li><p>perform the following ordered sub-steps to create anonymous spans:</p><ol class="enumla"><li><p>for each significant text node in a <a href="#terms-content-element">content element</a>,
-synthesize an anonymous span to enclose the text node, substituting
-the new anonymous span for the original text node child in its sibling
-and parent hierarchy;</p></li><li><p>for each contiguous sequence of anonymous spans, replace the
-sequence with a single anonymous span which contains a sequence of
-text nodes representing the individual text node children of the
-original sequence of anonymous spans;</p></li><li><p>for each span element whose child is a single anonymous span,
-replace the anonymous span with its sequence of child text
-nodes;</p></li></ol></li><li><p>resolve styles according to <a href="#semantics-style-resolution-process-overall"><b>10.4.4.4 Style Resolution Process</b></a>;</p></li><li><p>map the <code>tt</code> element to an <code>fo:root</code> element, populated
-initially with an <code>fo:layout-master-set</code> element that contains a valid
-<code>fo:simple-page-master</code> that, in turn, contains an
-<code>fo:region-body</code> child, where the extent of the <a href="#terms-root-container-region">root container region</a> expressed on the
-<code>tt</code> element is mapped to <code>page-width</code> and
-<code>page-height</code> attributes on the <code>fo:simple-page-master</code>
-element;</p></li><li><p>map the <code>layout</code> element to an <code>fo:page-sequence</code> element and a
-child <code>fo:flow</code> element that reference the page master and page region
-defined by the simple page master produced above;</p></li><li><p>map each non-empty <code>region</code> element to an <code>fo:block-container</code>
-element with an <code>absolute-position</code> attribute with value
-<code>absolute</code>, with <code>top</code>, <code>left</code>, <code>bottom</code>, and <code>right</code>
-attributes that express a rectangle equivalent to the region's origin and
-extent, and with a <code>line-stacking-strategy</code> attribute with value <code>line-height</code>;</p></li><li><p>for each <code>body</code>, <code>div</code>, and <code>p</code> element that is not
-associated with a <code>tts:display</code> style property with the value
-<code>none</code>, map the element to a distinct <code>fo:block</code> element,
-populating the style properties of <code>fo:block</code> by using the computed
-style set associated with each original TTML <a href="#terms-content-element">content element</a>;</p></li><li><p>for the resulting <code>fo:block</code> formatting object
-produced in the previous step that corresponds to the <code>body</code>
-element, perform the following ordered sub-steps:</p><ol class="enumla"><li><p>if the <code>display-align</code> style property of this <code>fo:block</code>
-has the value <code>center</code> or <code>after</code>,
-then synthesize and insert as the first child of this <code>fo:block</code>
-an empty <code>fo:block</code> with the following attributes:
-<code>space-after.optimum</code>, <code>space-after.maximum</code>, and
-<code>space-after.conditionality</code>, where the value of the former
-two attributes is the height or width of the containing
-<code>fo:block-container</code> element, whichever of these is designated
-as the block progression dimension, and where the value of the last is
-<code>retain</code>;</p></li><li><p>if the <code>display-align</code> style property of this <code>fo:block</code>
-has the value <code>center</code> or <code>before</code>,
-then synthesize and insert as the last child of this <code>fo:block</code>
-an empty <code>fo:block</code> with the following attributes:
-<code>space-after.optimum</code>, <code>space-after.maximum</code>, and
-<code>space-after.conditionality</code>, where the value of the former
-two attributes is the height or width of the containing
-<code>fo:block-container</code> element, whichever of these is designated
-as the block progression dimension, and where the value of the last is
-<code>retain</code>;</p></li></ol></li><li><p>for each <code>span</code> element that is not
-associated with a <code>tts:display</code> style property with the value
-<code>none</code> and for each anonymous
-span that is a child of a <code>p</code> or <code>span</code> element,
-map the element or
-sequence of character items to a distinct <code>fo:inline</code> element,
-populating the style properties of <code>fo:inline</code> by using the computed
-style set associated with each original TTML <a href="#terms-content-element">content element</a>
-or anonymous span;</p></li><li><p>for each <code>br</code> element that is not
-associated with a <code>tts:display</code> style property with the value
-<code>none</code>, map the element to
-a distinct <code>fo:character</code> element having the following
-properties:</p><ul><li><p><code>character="&amp;#x000A;"</code></p></li><li><p><code>suppress-at-line-break="retain"</code></p></li></ul></li><li><p>for each TTML style property attribute in some computed
-style set that
-has no counterpart in <a href="#xsl11">[XSL 1.1]</a>, map that attribute directly through
-to the relevant formatting object produced by the input TTML <a href="#terms-content-element">content element</a> to
-which the style property applies;</p></li><li><p>optionally, synthesize a unique <code>id</code> attribute on each resulting
-formatting object element that relates that element to the input element that
-resulted in that formatting object element;</p></li></ol><p>For each resulting document instance F, if processing requires presentation on a 
-visual medium, then apply formatting and rendering semantics consistent with that 
-prescribed by <a href="#xsl11">[XSL 1.1]</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In an XSL FO area tree produced by formatting <em>F</em> using 
-an <a href="#xsl11">[XSL 1.1]</a> formatting processor, 
-the <code>page-viewport-area</code>,
-which is generated by <code>fo:page-sequence</code> element by
-reference to the sole generated <code>fo:simple-page-master</code>
-element, would correspond to the <a href="#terms-root-container-region">root container region</a> defined
-above in <a href="#definitions"><b>2 Definitions</b></a>.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>When mapping a <code>region</code> element to <code>fo:block-container</code>, it may
-be necessary to use a negative offset as a value for one or more of the
-<code>top</code>, <code>left</code>, <code>bottom</code>, and <code>right</code>
-XSL-FO properties in case the region extends outside of its containing block.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Due to the possible presence of TTML style properties or style property values
-in a given <a href="#terms-document-instance">document instance</a> for which there is no <a href="#xsl11">[XSL 1.1]</a> counterpart,
-Implementors should recognize that it is the layout model of <a href="#xsl11">[XSL 1.1]</a> that is being referenced
-by this specification, not the requirement to use a compliant <a href="#xsl11">[XSL 1.1]</a> formatting processor,
-since such would not necessarily be sufficient to satisfy the full presentation semantics
-defined by this specification, and would contain a large number of features not needed to
-implement the presentation semantics of TTML.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The purpose of inserting additional, collapsible space in the block progression
-dimension of the <code>fo:block</code> that corresponds with the <code>body</code> element
-is to ensure that the before and after edges of this <code>fo:block</code> are coincident
-with the before and after edges of the <code>fo:block-container</code> that corresponds
-to the containing <code>region</code>, while simultaneously taking into account the needs
-to satisfy alignment in the block progression dimension. For example, this assures that
-the background color associated with the <code>body</code> element, if not <code>transparent</code>,
- will fill the containing region wholly.</p></div></div><div class="div4">
-<h5><a id="semantics-region-layout-example"></a>11.3.1.5 Elaborated Example (Non-Normative)</h5><p>An example of the processing steps described above is elaborated below, starting with <a href="#region-mapping-example-1-s"><b>Example – Sample Source Document</b></a>.</p><a id="region-mapping-example-1-s"></a><table class="example"><caption>Example – Sample Source Document</caption><tbody><tr><td>
-<div class="exampleInner"><pre>&lt;tt tts:extent="640px 480px" xml:lang="en"
-  xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;head&gt;
-    &lt;layout&gt;
-      &lt;region xml:id="r1"&gt;
-        &lt;style tts:origin="10px 100px"/&gt;
-        &lt;style tts:extent="620px 96px"/&gt;
-        &lt;style tts:fontSize="40px"/&gt;
-        &lt;style tts:fontWeight="bold"/&gt;
-        &lt;style tts:backgroundColor="black"/&gt;
-        &lt;style tts:color="red"/&gt;
-        &lt;style tts:textAlign="center"/&gt;
-        &lt;style tts:displayAlign="center"/&gt;
-      &lt;/region&gt;
-      &lt;region xml:id="r2"&gt;
-        &lt;style tts:origin="10px 300px"/&gt;
-        &lt;style tts:extent="620px 96px"/&gt;
-        &lt;style tts:fontSize="40px"/&gt;
-        &lt;style tts:fontWeight="bold"/&gt;
-        &lt;style tts:backgroundColor="black"/&gt;
-        &lt;style tts:color="yellow"/&gt;
-        &lt;style tts:textAlign="center"/&gt;
-        &lt;style tts:displayAlign="center"/&gt;
-      &lt;/region&gt;
-    &lt;/layout&gt;
-  &lt;/head&gt;
-  &lt;body xml:id="b1"&gt;
-    &lt;div xml:id="d1" begin="0s" dur="2s"&gt;
-      &lt;p xml:id="p1" region="r1"&gt;Text 1&lt;/p&gt;
-      &lt;p xml:id="p2" region="r2"&gt;Text 2&lt;/p&gt;
-    &lt;/div&gt;
-    &lt;div xml:id="d2" begin="1s" dur="2s"&gt;
-      &lt;p xml:id="p3" region="r2"&gt;Text 3&lt;/p&gt;
-      &lt;p xml:id="p4" region="r1"&gt;Text 4&lt;/p&gt;
-    &lt;/div&gt;
-  &lt;/body&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p>In the above document, the content hierarchy consists of two divisions, each
-containing two paragraphs. This content is targeted (associated with) one of two
-non-overlapping regions that are styled identically except for their position
-and their foreground colors, the latter of which is inherited by and applies to
-the (and, in this case, anonymous) spans reparented into the regions.</p><p>The following, first intermediate document shows the synchronic state for time
-interval [0,1), during which time only division <code>d1</code> is temporally active,
-and where paragraphs <code>p1</code> and <code>p2</code> (and their ancestors)
-are associated with regions <code>r1</code> and <code>r2</code>, respectively.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The intermediate documents shown below are not valid <a href="#terms-document-instance">document instances</a>,
-but rather, are representations of possible internal processing states used for
-didactic purposes.</p></div><a id="region-mapping-example-1-i0"></a><table class="example"><caption>Example – Intermediate Document – [0s,1s)</caption><tbody><tr><td>
-<div class="exampleInner"><pre>&lt;tt tts:extent="640px 480px" xml:lang="en"
-  xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;head&gt;
-    &lt;layout&gt;
-      &lt;region xml:id="r1"&gt;
-        &lt;style tts:origin="10px 100px"/&gt;
-        &lt;style tts:extent="620px 96px"/&gt;
-        &lt;style tts:fontSize="40px"/&gt;
-        &lt;style tts:fontWeight="bold"/&gt;
-        &lt;style tts:backgroundColor="black"/&gt;
-        &lt;style tts:color="red"/&gt;
-        &lt;style tts:textAlign="center"/&gt;
-        &lt;style tts:displayAlign="center"/&gt;
-        &lt;body xml:id="b1-1"&gt;
-          &lt;div xml:id="d1-1"&gt;
-            &lt;p xml:id="p1"&gt;Text 1&lt;/p&gt;
-          &lt;/div&gt;
-        &lt;/body&gt;
-      &lt;/region&gt;
-      &lt;region xml:id="r2"&gt;
-        &lt;style tts:origin="10px 300px"/&gt;
-        &lt;style tts:extent="620px 96px"/&gt;
-        &lt;style tts:fontSize="40px"/&gt;
-        &lt;style tts:fontWeight="bold"/&gt;
-        &lt;style tts:backgroundColor="black"/&gt;
-        &lt;style tts:color="yellow"/&gt;
-        &lt;style tts:textAlign="center"/&gt;
-        &lt;style tts:displayAlign="center"/&gt;
-        &lt;body xml:id="b1-2"&gt;
-          &lt;div xml:id="d1-2"&gt;
-            &lt;p xml:id="p2"&gt;Text 2&lt;/p&gt;
-          &lt;/div&gt;
-        &lt;/body&gt;
-      &lt;/region&gt;
-    &lt;/layout&gt;
-  &lt;/head&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p>An XSL FO document instance that would yield rendering consistent with TTML, and 
-which may be produced by performing flow processing upon the first intermediate 
-document is illustrated below.</p><a id="region-mapping-example-1-f0"></a><table class="example"><caption>Example – XSL FO Document – [0s,1s)</caption><tbody><tr><td>
-<div class="exampleInner"><pre>&lt;fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format"&gt;
-  &lt;fo:layout-master-set&gt;
-    &lt;fo:simple-page-master master-name="m1"
-      page-width="640px" page-height="480px"&gt;
-      &lt;fo:region-body/&gt;
-    &lt;/fo:simple-page-master&gt;
-  &lt;/fo:layout-master-set&gt;
-  &lt;fo:page-sequence master-reference="m1"&gt;
-    &lt;fo:flow flow-name="xsl-region-body"&gt;
-      &lt;!-- region (r1) --&gt;
-      &lt;fo:block-container id="r1" absolute-position="absolute"
-        left="10px" top="100px" width="620px" height="96px"
-        background-color="black" display-align="center"&gt;
-        &lt;!-- body (b1) --&gt;
-        &lt;fo:block id="b1-1"&gt;
-          &lt;!-- body's space (before) filler --&gt;
-          &lt;fo:block
-            space-after.optimum="96px"
-            space-after.maximum="96px"
-            space-after.conditionality="retain"/&gt;
-          &lt;!-- div (d1) --&gt;
-          &lt;fo:block id="d1-1"&gt;
-            &lt;!-- p (p1) --&gt;
-            &lt;fo:block id="p1" text-align="center"&gt;
-              &lt;fo:inline font-size="40px" font-weight="bold"
-              color="red"&gt;Text 1&lt;/fo:inline&gt;
-            &lt;/fo:block&gt;
-          &lt;/fo:block&gt;
-          &lt;!-- body's space (after) filler --&gt;
-          &lt;fo:block
-            space-after.optimum="96px"
-            space-after.maximum="96px"
-            space-after.conditionality="retain"/&gt;
-        &lt;/fo:block&gt;
-      &lt;/fo:block-container&gt;
-      &lt;!-- region (r2) --&gt;
-      &lt;fo:block-container id="r2" absolute-position="absolute"
-        left="10px" top="300px" width="620px" height="96px"
-        background-color="black" display-align="center"&gt;
-        &lt;!-- body (b1) --&gt;
-        &lt;fo:block id="b1-2"&gt;
-          &lt;!-- body's space (before) filler --&gt;
-          &lt;fo:block
-            space-after.optimum="96px"
-            space-after.maximum="96px"
-            space-after.conditionality="retain"/&gt;
-          &lt;!-- div (d1) --&gt;
-          &lt;fo:block id="d1-2"&gt;
-            &lt;!-- p (p2) --&gt;
-            &lt;fo:block id="p2" text-align="center"&gt;
-              &lt;fo:inline font-size="40px" font-weight="bold"
-              color="yellow"&gt;Text 2&lt;/fo:inline&gt;
-            &lt;/fo:block&gt;
-          &lt;/fo:block&gt;
-          &lt;!-- body's space (after) filler --&gt;
-          &lt;fo:block
-            space-after.optimum="96px"
-            space-after.maximum="96px"
-            space-after.conditionality="retain"/&gt;
-        &lt;/fo:block&gt;
-      &lt;/fo:block-container&gt;
-    &lt;/fo:flow&gt;
-  &lt;/fo:page-sequence&gt;
-&lt;/fo:root&gt;
-</pre></div>
-</td></tr></tbody></table><p>The following, second intermediate document shows the synchronic state for
-time interval [1,2), during which time both divisions <code>d1</code> and
-<code>d2</code> are temporally active, and where paragraphs <code>p1</code> and
-<code>p4</code> (and their ancestors) are associated with region <code>r1</code>
-and paragraphs <code>p2</code> and <code>p3</code> (and their ancestors) are
-associated with region <code>r2</code>.</p><a id="region-mapping-example-1-i1"></a><table class="example"><caption>Example – Intermediate Document – [1s,2s)</caption><tbody><tr><td>
-<div class="exampleInner"><pre>&lt;tt tts:extent="640px 480px" xml:lang="en"
-  xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;head&gt;
-    &lt;layout&gt;
-      &lt;region xml:id="r1"&gt;
-        &lt;style tts:origin="10px 100px"/&gt;
-        &lt;style tts:extent="620px 96px"/&gt;
-        &lt;style tts:fontSize="40px"/&gt;
-        &lt;style tts:fontWeight="bold"/&gt;
-        &lt;style tts:backgroundColor="black"/&gt;
-        &lt;style tts:color="red"/&gt;
-        &lt;style tts:textAlign="center"/&gt;
-        &lt;style tts:displayAlign="center"/&gt;
-        &lt;body xml:id="b1-1"&gt;
-          &lt;div xml:id="d1-1"&gt;
-            &lt;p xml:id="p1"&gt;Text 1&lt;/p&gt;
-          &lt;/div&gt;
-          &lt;div xml:id="d2-1"&gt;
-            &lt;p xml:id="p4"&gt;Text 4&lt;/p&gt;
-          &lt;/div&gt;
-        &lt;/body&gt;
-      &lt;/region&gt;
-      &lt;region xml:id="r2"&gt;
-        &lt;style tts:origin="10px 300px"/&gt;
-        &lt;style tts:extent="620px 96px"/&gt;
-        &lt;style tts:fontSize="40px"/&gt;
-        &lt;style tts:fontWeight="bold"/&gt;
-        &lt;style tts:backgroundColor="black"/&gt;
-        &lt;style tts:color="yellow"/&gt;
-        &lt;style tts:textAlign="center"/&gt;
-        &lt;style tts:displayAlign="center"/&gt;
-        &lt;body xml:id="b1-2"&gt;
-          &lt;div xml:id="d1-2"&gt;
-            &lt;p xml:id="p2"&gt;Text 2&lt;/p&gt;
-          &lt;/div&gt;
-          &lt;div xml:id="d2-2"&gt;
-            &lt;p xml:id="p3"&gt;Text 3&lt;/p&gt;
-          &lt;/div&gt;
-        &lt;/body&gt;
-      &lt;/region&gt;
-    &lt;/layout&gt;
-  &lt;/head&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><p>The following, third intermediate document shows the synchronic state for time
-interval [2,3), during which time only division <code>d2</code> is temporally active,
-and where paragraphs <code>p4</code> and <code>p3</code> (and their ancestors)
-are associated with regions <code>r1</code> and <code>r2</code>, respectively.</p><a id="region-mapping-example-1-i2"></a><table class="example"><caption>Example – Intermediate Document – [2s,3s)</caption><tbody><tr><td>
-<div class="exampleInner"><pre>&lt;tt tts:extent="640px 480px" xml:lang="en"
-  xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;head&gt;
-    &lt;layout&gt;
-      &lt;region xml:id="r1"&gt;
-        &lt;style tts:origin="10px 100px"/&gt;
-        &lt;style tts:extent="620px 96px"/&gt;
-        &lt;style tts:fontSize="40px"/&gt;
-        &lt;style tts:fontWeight="bold"/&gt;
-        &lt;style tts:backgroundColor="black"/&gt;
-        &lt;style tts:color="red"/&gt;
-        &lt;style tts:textAlign="center"/&gt;
-        &lt;style tts:displayAlign="center"/&gt;
-        &lt;body xml:id="b1-1"&gt;
-          &lt;div xml:id="d2-1"&gt;
-            &lt;p xml:id="p4"&gt;Text 4&lt;/p&gt;
-          &lt;/div&gt;
-        &lt;/body&gt;
-      &lt;/region&gt;
-      &lt;region xml:id="r2"&gt;
-        &lt;style tts:origin="10px 300px"/&gt;
-        &lt;style tts:extent="620px 96px"/&gt;
-        &lt;style tts:fontSize="40px"/&gt;
-        &lt;style tts:fontWeight="bold"/&gt;
-        &lt;style tts:backgroundColor="black"/&gt;
-        &lt;style tts:color="yellow"/&gt;
-        &lt;style tts:textAlign="center"/&gt;
-        &lt;style tts:displayAlign="center"/&gt;
-        &lt;body xml:id="b1-2"&gt;
-          &lt;div xml:id="d2-2"&gt;
-            &lt;p xml:id="p3"&gt;Text 3&lt;/p&gt;
-          &lt;/div&gt;
-        &lt;/body&gt;
-      &lt;/region&gt;
-    &lt;/layout&gt;
-  &lt;/head&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table></div></div><div class="div3">
-<h4><a id="semantics-line-layout"></a>11.3.2 Line Layout</h4><p>If a profile that applies to a <a href="#terms-document-instance">document instance</a>
-requires use of the <a href="#feature-lineBreak-uax14">#lineBreak-uax14</a> feature
-(i.e., the value attribute for the feature is specified as <code>use</code>), then
-the recommendations defined by <a href="http://www.unicode.org/reports/tr14/#Algorithm">Line
-Breaking Algorithm</a> <a href="#uax14">[UAX14]</a> apply when performing
-line layout on the content of the <a href="#terms-document-instance">document instance</a>.</p></div></div></div><div class="div1">
-<h2><a id="timing"></a>12 Timing</h2><p>This section specifies the <em>timing</em> matter of the core
-vocabulary catalog, where
-timing is to be understood as a separable layer of information that applies to
-content and that denotes authorial intentions about the temporal presentation of
-that content.</p><div class="div2">
-<h3><a id="timing-element-vocabulary"></a>12.1 Timing Element Vocabulary</h3><p>No timing related element vocabulary is defined for use in the core
-vocabulary catalog.</p></div><div class="div2">
-<h3><a id="timing-attribute-vocabulary"></a>12.2 Timing Attribute Vocabulary</h3><p>This section defines the following basic timing attributes for use with timed elements:</p><ul><li><p><a href="#timing-attribute-begin"><b>12.2.1 begin</b></a></p></li><li><p><a href="#timing-attribute-dur"><b>12.2.2 dur</b></a></p></li><li><p><a href="#timing-attribute-end"><b>12.2.3 end</b></a></p></li></ul><p>In addition, this section defines the <a href="#timing-attribute-timeContainer"><b>12.2.4 timeContainer</b></a> attribute for use with timed elements
-that serve simultaneously as timing containers.</p><div class="div3">
-<h4><a id="timing-attribute-begin"></a>12.2.1 begin</h4><p>The <code>begin</code> attribute is used to specify the begin
-point of a temporal interval associated with a timed element. If
-specified, the value of a <code>begin</code> attribute must adhere to
-a &lt;timeExpression&gt; specification as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>The begin point of a temporal interval is included in the
-interval; i.e., the interval is left-wise closed.</p><p>The semantics of the <code>begin</code> attribute are those defined
-by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3,
-while taking into account any overriding semantics defined by this specification.</p></div><div class="div3">
-<h4><a id="timing-attribute-dur"></a>12.2.2 dur</h4><p>The <code>dur</code> attribute is used to specify the duration of a
-temporal interval associated with a timed element. If specified,
-the value of a <code>dur</code> attribute must adhere to a
-&lt;timeExpression&gt; specification as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When the <code>clock-time</code> form of a &lt;timeExpression&gt; specification
-is used with a <code>dur</code> attribute, it is intended to be interpreted as
-a difference between two implied clock time expressions.</p></div><p>When a <a href="#terms-document-instance">document instance</a> specifies the use of the
-<code>smpte</code> time base and <code>discontinuous</code> marker
-mode, a (well-formed) <code>dur</code> attribute must not be specified on any
-element.</p><p>The semantics of the <code>dur</code> attribute are those defined
-by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3,
-while taking into account any overriding semantics defined by this specification.
-In a deliberate divergence from <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3, the value of
-the <code>dur</code> attribute is permitted to be zero (0).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In the context of the subset of <a href="#smil3">[SMIL 3.0]</a> semantics supported by
-this specification, the active duration of an element that specifies both
-<code>end</code> and <code>dur</code> attributes is equal to the lesser of the value of
-the <code>dur</code> attribute and the difference between the value of the
-<code>end</code> attribute and the element's begin time.</p></div></div><div class="div3">
-<h4><a id="timing-attribute-end"></a>12.2.3 end</h4><p>The <code>end</code> attribute is used to specify the ending point
-of a temporal interval associated with a timed element. If
-specified, the value of an <code>end</code> attribute must adhere to a
-&lt;timeExpression&gt; specification as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>The ending point of a temporal interval is not included in the
-interval; i.e., the interval is right-wise open.</p><p>The presentation effects of a non-empty active
-temporal interval include the frame immediately prior to the frame
-(or tick) equal to or immediately following the time specified by the ending
-point, but do not extend into this latter frame (or tick).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, if an active interval is [10s,10.33333s), and the
-frame rate is 30 frames per second, then the presentation effects of the interval
-are limited to frames 300 through 309 only (assuming that 0s corresponds
-with frame 0). The same holds if the active interval is specified
-as [300f,310f).</p></div><p>The semantics of the <code>end</code> attribute are those defined
-by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3,
-while taking into account any overriding semantics defined by this specification.</p></div><div class="div3">
-<h4><a id="timing-attribute-timeContainer"></a>12.2.4 timeContainer</h4><p>The <code>timeContainer</code> attribute is used to specify a local temporal
-context by means of which timed child elements are temporally situated.</p><p>If specified, the value of a <code>timeContainer</code> attribute must be one
-of the following:</p><ul><li><p><code>par</code></p></li><li><p><code>seq</code></p></li></ul><p>If the time container semantics of an element instance is <code>par</code>,
-then the temporal intervals of child elements are considered to apply in
-parallel, i.e., simultaneously in time. Furthermore, the specification of
-the time interval of each child element is considered to be relative to the temporal
-interval of the container element instance. For the purpose of determining the
-<a href="#smil3">[SMIL 3.0]</a> <code>endsync</code> semantics of a <code>par</code>
-time container, a default value of <code>all</code> applies.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of a default value of <code>all</code> for the <code>endsync</code>
-behavior is distinct from <a href="#smil3">[SMIL 3.0]</a> which uses a default value
-of <code>last</code>.</p></div><p>If the time container semantics of an element instance is <code>seq</code>,
-then the temporal intervals of child elements are considered to apply in
-sequence, i.e., sequentially in time. Furthermore, the specification of
-the time interval of each child element is considered to be relative to the temporal
-interval of its sibling elements, unless it is the first child element, in which case
-it is considered to be relative to the temporal interval of the container
-element instance.</p><p>Each time container is considered to constitute an independent time base, i.e.,
-time coordinate system.</p><p>If a <code>timeContainer</code> attribute is not specified on an element that
-has time container semantics, then <code>par</code> time container semantics must apply.</p><p>Time container semantics applies only to the following element types:</p><ul><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li></ul><p>The semantics of parallel and sequential time
-containment are those defined by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.4,
-while taking into account any overriding semantics defined by this specification.</p></div></div><div class="div2">
-<h3><a id="timing-time-value-expressions"></a>12.3 Time Value Expressions</h3><p>Timing attribute values include the use of the following expressions:</p><ul><li><p><a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a></p></li></ul><div class="div3">
-<h4><a id="timing-value-timeExpression"></a>12.3.1 &lt;timeExpression&gt;</h4><p>A &lt;timeExpression&gt; is used to specify a coordinate within
-some time base, where the applicable time base is determined by the
-<code>ttp:timeBase</code> parameter, and where the semantics defined
-by <a href="#time-expression-semantics"><b>H Time Expression Semantics</b></a> apply.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See
-<a href="#parameter-attribute-frameRate"><b>7.2.4 ttp:frameRate</b></a>,
-<a href="#parameter-attribute-subFrameRate"><b>7.2.11 ttp:subFrameRate</b></a>,
-<a href="#parameter-attribute-tickRate"><b>7.2.12 ttp:tickRate</b></a>, and
-<a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a> for further information on
-explicit specification of frame rate, sub-frame rate, tick rate, and time base.</p></div><div class="issue"><p class="prefix"><a id="issue-293"></a><b>Issue (issue-293):</b></p><p class="prefix"><b>Dates in Time Expressions</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/293">http://www.w3.org/AudioVideo/TT/tracker/issues/293</a></p><p>Consider adding dates to time expressions to handle issues around midnight crossings and related use cases.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><a id="timeExpression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;timeExpression&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;timeExpression&gt;
-  : clock-time
-  | offset-time
-
-clock-time
-  : hours ":" minutes ":" seconds ( fraction | ":" frames ( "." sub-frames )? )?
-
-offset-time
-  : time-count fraction? metric?
-
-hours
-  : <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>
-  | <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>+
-
-minutes | seconds
-  : <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>
-
-frames
-  : <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>
-  | <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>+
-
-sub-frames
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-
-fraction
-  : "." <a href="#style-value-digit">&lt;digit&gt;</a>+
-
-time-count
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-
-metric
-  : "h"                 // hours
-  | "m"                 // minutes
-  | "s"                 // seconds
-  | "ms"                // milliseconds
-  | "f"                 // frames
-  | "t"                 // ticks
-</pre></div>
-</td></tr></tbody></table><p>If a &lt;timeExpression&gt; is expressed in terms of a
-<em>clock-time</em>, then leading zeroes are used when expressing hours,
-minutes, seconds, and frames less than 10. Minutes are constrained to
-[0…59], while seconds (including any fractional part) are constrained to the closed
-interval [0,60], where the value 60 applies only to leap seconds.</p><p>If a &lt;timeExpression&gt; is expressed in terms of a
-<em>clock-time</em> and a <em>frames</em> term is specified,
-then the value of this term must be constrained to the interval
-[0…<em>F-1</em>], where <em>F</em> is the frame rate
-determined by the <code>ttp:frameRate</code> parameter as defined
-by <a href="#parameter-attribute-frameRate"><b>7.2.4 ttp:frameRate</b></a>.
-It is considered an error if a <em>frames</em> term or
-<code>f</code> (frames) metric is specified when the <code>clock</code> time base applies.</p><p>If a &lt;timeExpression&gt; is expressed in terms of a
-<em>clock-time</em> and a <em>sub-frames</em> term is
-specified, then the value of this term must be constrained to the
-interval [0…<em>S-1</em>], where <em>S</em> is the
-sub-frame rate determined by the <code>ttp:subFrameRate</code> parameter as defined by <a href="#parameter-attribute-subFrameRate"><b>7.2.11 ttp:subFrameRate</b></a>.
-It is considered an error if a <em>sub-frames</em> term is specified
-when the <code>clock</code> time base applies.</p><p>If a &lt;timeExpression&gt; is expressed in terms of an
-<em>offset-time</em> and no <em>metric</em> is specified, then it is to be treated as
-if a metric of <code>s</code> (seconds) were specified.</p></div></div><div class="div2">
-<h3><a id="semantics-timing"></a>12.4 Timing Semantics</h3><p>The semantics of time containment, durations, and intervals defined by
-<a href="#smil3">[SMIL 3.0]</a> apply to the interpretation of like-named timed elements and timing
-vocabulary defined by this specification, given the following
-constraints:</p><div class="issue"><p class="prefix"><a id="issue-338"></a><b>Issue (issue-338):</b></p><p class="prefix"><b>Implicit Duration of Singleton Span</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/338">http://www.w3.org/AudioVideo/TT/tracker/issues/338</a></p><p>Refine definition implicit duration of singleton span in a sequential container.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><ul><li><p>The implicit duration of an anonymous span is defined as follows: if
-the anonymous span's parent time container is a parallel time container, then
-the implicit duration is equivalent to the <code>indefinite</code>
-duration value as defined by <a href="#smil3">[SMIL 3.0]</a>; if the anonymous span's
-parent time container is a sequential time container, then the implicit duration
-is equivalent to zero.</p></li><li><p>The implicit duration of a <code>body</code>, <code>div</code>, <code>p</code>,
-or <code>span</code> element is determined in accordance to (1) whether
-the element is a parallel or sequential time container, (2) the default
-<code>endsync</code> semantics defined above by <a href="#timing-attribute-timeContainer"><b>12.2.4 timeContainer</b></a>,
-and (3) the semantics of <a href="#smil3">[SMIL 3.0]</a> as applied to these time
-containers.</p></li><li><p>The implicit duration of the <code>region</code> element is defined to
-be equivalent to the <code>indefinite</code>
-duration value as defined by <a href="#smil3">[SMIL 3.0]</a>.</p></li><li><p>If the governing time base is <code>clock</code>, then time
-expressions are considered to be equivalent to wall-clock
-based timing in <a href="#smil3">[SMIL 3.0]</a>, where the specific semantics of
-<a href="#time-expression-semantics-clock"><b>H.1 Clock Time Base</b></a> apply.</p></li><li><p>If the governing time base is <code>media</code>, then time
-expressions are considered to be equivalent to offset based timing
-in <a href="#smil3">[SMIL 3.0]</a>, where the specific semantics of
-<a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> apply.</p></li><li><p>If the governing time base is <code>smpte</code>, then time
-expressions are considered to be equivalent to either offset
-based timing or event based timing in <a href="#smil3">[SMIL 3.0]</a>, where the specific semantics of
-<a href="#time-expression-semantics-smpte"><b>H.3 SMPTE Time Base</b></a> apply.</p></li></ul></div></div><div class="div1">
-<h2><a id="animation"></a>13 Animation</h2><p>This section specifies the <em>animation</em> matter of the
-core vocabulary catalog, where
-animation is to be understood as a separable layer of information that combines
-timing and styling in order to denote authorial intention about (temporally) dynamic
-styling of content.</p><table border="1" class="ednote" summary="Editorial note: Out-of-Line Animation Time Containment"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Out-of-Line Animation Time Containment</b></td><td align="right" valign="top">2014-07-31</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Support ability for author to declare whether a referenced out-of-line animation's timing is relative
-to its <code>animation</code> container element's timing or relative to the referring element's timing.
-For example, add an <code>@animateTimeContainer</code> attribute optionally used with the newly defined
-<code>@animate</code> attribute, where value can be <code>normal</code> (the default value) or <code>self</code>, and where <code>normal</code>
-means timing is with respect to the out-of-line animation element's ancestor <code>animation</code> container and <code>self</code> means timing is
-with respect to the referring element.</td></tr></table><div class="div2">
-<h3><a id="animation-element-vocabulary"></a>13.1 Animation Element Vocabulary</h3><p>The following elements specify the structure and principal animation aspects of a
-<a href="#terms-document-instance">document instance</a>:</p><ul><li><p><a href="#animation-vocabulary-animate"><b>13.1.1 animate</b></a></p></li><li><p><a href="#animation-vocabulary-animation"><b>13.1.2 animation</b></a></p></li><li><p><a href="#animation-vocabulary-set"><b>13.1.3 set</b></a></p></li></ul><div class="div3">
-<h4><a id="animation-vocabulary-animate"></a>13.1.1 animate</h4><p>The <code>animate</code> element expresses a series of changes (animations) to be applied (targeted) to one or more style property attributes of associated elements.</p><div class="issue"><p class="prefix"><a id="issue-355"></a><b>Issue (issue-355):</b></p><p class="prefix"><b>Marquee</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/355">http://www.w3.org/AudioVideo/TT/tracker/issues/355</a></p><p>Consider whether semantics of ARIB-TT's marquee extension can be handled by <code>animate</code>, and, if not, then consider extending.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>An <code>animate</code> element may appear as either (1) a child of a
-<a href="#terms-content-element">content element</a> or a <a href="#layout-vocabulary-region"><code>region</code></a> element,
-referred to as <a href="#terms-inline-animation">inline animation</a>, or
-(2) a child of an <a href="#animation-vocabulary-animation">animation</a> element, referred to as
-<a href="#terms-out-of-line-animation">out-of-line animation</a>.
-In the former case, the parent of the <code>animate</code> element is the associated element; in the latter
-case, any element that references the <code>animate</code> element using an <code>animate</code> attribute is
-an associated element.</p><p>The <code>animate</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group.</p><a id="elt-syntax-animate"></a><table class="syntax"><caption>XML Representation – Element Information Item: animate</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;animate
-  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  calcMode = <a href="#animation-value-calcMode">&lt;calcMode&gt;</a>
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  fill = <a href="#animation-value-fill">&lt;fill&gt;</a>
-  keySplines = <a href="#animation-value-keySplines">&lt;keySplines&gt;</a>
-  keyTimes = <a href="#animation-value-keyTimes">&lt;keyTimes&gt;</a>
-  repeatCount = <a href="#animation-value-repeatCount">&lt;repeatCount&gt;</a>
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
-&lt;/animate&gt;
-</pre></div>
-</td></tr></tbody></table><p>An <a href="#terms-out-of-line-animation">out-of-line</a> <code>animate</code> element
-must specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute.</p><p>Style property attributes targeted by an <code>animate</code> element are specified directly using
-attributes in the TT Style namespace or in a namespace that is not a TT namespace, where the list (sequence) of animation (key) values
-adhere to the <a href="#animation-value-animationValueList">&lt;animationValueList&gt;</a> syntax, and where each
-constituent <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> adheres to the syntax of the specified
-attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In contrast with <a href="#svg11">[SVG 1.1]</a>, §19.2.12, a single <code>animate</code> element, as defined here, may be used to
-perform continuous animations on a set of targeted style property attributes instead of being limited to targeting a single style property attribute.
-In <a href="#svg11">[SVG 1.1]</a>, this would require the use of multiple <code>animate</code> elements rather than a single <code>animate</code> element.</p><p>Furthermore, by using direct specification of animated style property and key values, it is not necessary to employ the <code>from</code>,
-<code>to</code>, <code>by</code>, or <code>values</code> animation value attributes defined by <a href="#svg11">[SVG 1.1]</a>, §19.2.9.</p></div><p>Except for the constraints or variations enumerated below, the semantics of the <code>animate</code> element and its attributes
-enumerated above are defined to be those specified by <a href="#svg11">[SVG 1.1]</a>, §19.2.12:</p><ol class="enumar"><li><p>The attributes targeted by an <code>animate</code> element and the key values to be applied to these attributes are
-specified by direct use of attributes in the TT Style namespace or a namespace that is not a TT namespace (as opposed to using
-SVG's <code>attributeName</code> and <code>from</code>,  <code>to</code>, <code>by</code>, or <code>values</code> attributes).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, specifying <code>tts:color="red;green;blue"</code> is
-considered equivalent to specifying <code>attributeName="tts:color"</code> and <code>values="red;green;blue"</code> in <a href="#svg11">[SVG 1.1]</a>.</p></div></li><li><p>If no <code>calcMode</code> attribute is specified, then a <em>calcMode</em> value of <code>linear</code> applies.</p></li><li><p>If no <code>fill</code> attribute is specified, then a <em>fill</em> value of <code>remove</code> applies.</p></li></ol><p>An example of using the <code>animate</code> element to animate content
-styling is illustrated below:</p><a id="animation-vocabulary-animate-example-1"></a><table class="example"><caption>Example Fragment – Content Style Animation</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;p dur="5s"&gt;
-<span class="strong">&lt;animate tts:color="yellow;red;green;blue;yellow"/&gt;</span>
-Text with Continuously Varying Colors!
-&lt;/p&gt;
-...
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the foreground color of the content "Text
-with Continuously Varying Colors!" is continuously animated from yellow, to red, to green, to
-red, then back to yellow over a 5 second period.</p></div><p>An example of using the <code>animate</code> element to animate region
-styling is illustrated below:</p><a id="animation-vocabulary-animate-example-2"></a><table class="example"><caption>Example Fragment – Region Style Animation</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"
-    xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
-    xmlns:tts="http://www.w3.org/ns/ttml#styling"
-    ttp:extent="640px 480px"&gt;
-    &lt;head&gt;
-      &lt;layout&gt;
-	&lt;region xml:id="r1" timeContainer="seq" tts:opacity="0"&gt;
-	  <span class="strong">&lt;animate dur="1s" tts:opacity="0;1"/&gt;</span>
-	  &lt;set dur="5s" tts:opacity="1"/&gt;
-	  <span class="strong">&lt;animate dur="1s" tts:opacity="1;0"/&gt;</span>
-	  &lt;style tts:extent="480px 60px"/&gt;
-	  &lt;style tts:origin="80px 400px"/&gt;
-	&lt;/region&gt;
-      &lt;/layout&gt;
-    &lt;/head&gt;
-    &lt;body region="r1"&gt;...&lt;/body&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, a region, <code>r1</code>, is initially set to 0% opacity,
-fully transparent, then is faded in to 100% opacity, fully opaque, over a one second
-interval. Opacity remains at 100% for five more seconds, and then is faded out to 0%
-over a one second interval, where it remains.</p></div><p></p><table border="1" class="ednote" summary="Editorial note: Animate Example Images"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Animate Example Images</b></td><td align="right" valign="top">2013-08-25</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert animated SVG images of animate examples.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the <code>animate</code> element
-are based upon that defined by <a href="#svg11">[SVG 1.1]</a>,
-§19.2.12, which, in turn, is based upon <a href="#smil3">[SMIL 3.0]</a>, §12.</p></div></div><div class="div3">
-<h4><a id="animation-vocabulary-animation"></a>13.1.2 animation</h4><p>The <code>animation</code> element is a container element used to group
-<a href="#terms-out-of-line-animation">out-of-line animation</a> matter, including metadata that applies to animation matter.</p><p>The <code>animation</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by
-zero or more elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group.</p><a id="elt-syntax-animation"></a><table class="syntax"><caption>XML Representation – Element Information Item: animation</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;animation
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*
-&lt;/animation&gt;
-</pre></div>
-</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
-<code>animation</code> element, the implied time interval of this element is
-defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div><div class="div3">
-<h4><a id="animation-vocabulary-set"></a>13.1.3 set</h4><p>The <code>set</code> element expresses one or more a discrete changes (animations) to be applied (targeted) to style property attributes
-of associated elements.</p><p>A <code>set</code> element may appear as either (1) a child of a
-<a href="#terms-content-element">content element</a> or a <a href="#layout-vocabulary-region"><code>region</code></a> element,
-referred to as <a href="#terms-inline-animation">inline animation</a>, or
-(2) a child of an <a href="#animation-vocabulary-animation">animation</a> element, referred to as
-<a href="#terms-out-of-line-animation">out-of-line animation</a>.
-In the former case, the parent of the <code>set</code> element is the associated element; in the latter
-case, any element that references the <code>set</code> element using an <code>animate</code> attribute is
-an associated element.</p><p>The <code>set</code> element accepts as its children zero or more
-elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group.</p><a id="elt-syntax-set"></a><table class="syntax"><caption>XML Representation – Element Information Item: set</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;set
-  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  fill = <a href="#animation-value-fill">&lt;fill&gt;</a>
-  repeatCount = <a href="#animation-value-repeatCount">&lt;repeatCount&gt;</a>
-  <a href="#style-attribute-style">style</a> = IDREFS
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
-&lt;/set&gt;
-</pre></div>
-</td></tr></tbody></table><p>Style property attributes targeted by an <code>set</code> element are specified directly using
-attributes in the TT Style namespace or in a namespace that is not some TT namespace, where the single target animation (key) value
-adheres to the <a href="#animation-value-animationValueList">&lt;animationValueList&gt;</a> syntax, where each
-constituent <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> adheres to the syntax of the specified
-attribute, and where exactly one constituent <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> is specified.</p><p>If more than one constituent <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> is specified, then all
-constituents other than the first must be ignored for the purpose of presentation processing, and must be considered an error for the
-purpose of validation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In contrast with <a href="#svg11">[SVG 1.1]</a>, §19.2.13, a single <code>set</code> element, as defined here, may be used to
-perform discrete animations on a set of targeted style property attributes instead of being limited to targeting a single style property attribute.
-In <a href="#svg11">[SVG 1.1]</a>, this would require the use of multiple <code>set</code> elements rather than a single <code>set</code> element.</p></div><p>Except for the constraints or variations enumerated below, the semantics of the <code>set</code> element and its attributes
-enumerated above are defined to be those specified by <a href="#svg11">[SVG 1.1]</a>, §19.2.13:</p><ol class="enumar"><li><p>The attributes targeted by a <code>set</code> element and the discrete values to be applied to these attributes are
-specified by direct use of attributes in the TT Style namespace or in a namespace that is not a TT namespace (as opposed to using SVG's
-<code>attributeName</code> and <code>to</code> attributes).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, specifying <code>tts:color="red"</code> is
-considered equivalent to specifying <code>attributeName="tts:color"</code> and <code>to="red"</code> in <a href="#svg11">[SVG 1.1]</a>.</p></div></li><li><p>If no <code>fill</code> attribute is specified, then a <em>fill</em> value of <code>remove</code> applies.</p></li></ol><p>An example of using the <code>set</code> element to animate content
-styling is illustrated below:</p><a id="animation-vocabulary-set-example-1"></a><table class="example"><caption>Example Fragment – Content Style Animation</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;p dur="5s" tts:color="yellow"&gt;
-<span class="strong">&lt;set begin="1s" dur="1s" tts:color="red"/&gt;</span>
-<span class="strong">&lt;set begin="2s" dur="1s" tts:color="green"/&gt;</span>
-<span class="strong">&lt;set begin="3s" dur="1s" tts:color="red"/&gt;</span>
-Text with Flashing Colors!
-&lt;/p&gt;
-...
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the foreground color of the content "Text
-with Flashing Colors!" is animated from yellow, to red, to green, to
-red, then back to yellow over a 5 second period.</p></div><p>An example of using the <code>set</code> element to animate region
-styling is illustrated below:</p><a id="animation-vocabulary-set-example-2"></a><table class="example"><caption>Example Fragment – Region Style Animation</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"
-    xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
-    xmlns:tts="http://www.w3.org/ns/ttml#styling"
-    ttp:cellResolution="40 16"&gt;
-    &lt;head&gt;
-      &lt;layout&gt;
-	&lt;region xml:id="r1" timeContainer="seq"&gt;
-	  <span class="strong">&lt;set dur="10s" tts:origin=" 8c 14c"/&gt;</span>
-	  <span class="strong">&lt;set dur="2s"  tts:origin=" 2c  2c"/&gt;</span>
-	  <span class="strong">&lt;set dur="3s"  tts:origin=" 8c 14c"/&gt;</span>
-	  <span class="strong">&lt;set dur="2s"  tts:origin="14c  4c"/&gt;</span>
-	  <span class="strong">&lt;set dur="10s" tts:origin=" 8c 14c"/&gt;</span>
-	  &lt;style tts:extent="24c 2c"/&gt;
-	&lt;/region&gt;
-      &lt;/layout&gt;
-    &lt;/head&gt;
-    &lt;body region="r1"&gt;...&lt;/body&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the <a href="#terms-root-container-region">root container region</a> is divided into a
-cell grid of 40 columns and 16 rows. A region, <code>r1</code>, with
-dimensions of 24 columns and 2 rows is then positioned within the
-<a href="#terms-root-container-region">root container region</a>, with its position varying over time in order to
-create an effect of moving the region, which may be desirable so as
-to avoid obscuring characters in an underlying video with captions.</p></div><p></p><table border="1" class="ednote" summary="Editorial note: Set Example Images"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Set Example Images</b></td><td align="right" valign="top">2013-08-25</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert animated SVG images of set examples.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the <code>set</code> element
-are based upon that defined by <a href="#svg11">[SVG 1.1]</a>,
-§19.2.13, which, in turn, is based upon <a href="#smil3">[SMIL 3.0]</a>, §12.</p></div></div></div><div class="div2">
-<h3><a id="animation-attribute-vocabulary"></a>13.2 Animation Attribute Vocabulary</h3><p>This section defines the <a href="#animation-attribute-animate"><b>13.2.1 animate</b></a> attribute used with <a href="#terms-content-element">content elements</a>
-and certain layout elements.</p><div class="div3">
-<h4><a id="animation-attribute-animate"></a>13.2.1 animate</h4><p>The <code>animate</code> attribute is used
-to reference one or more <a href="#animation-vocabulary-animate"><code>animate</code></a>
-or <a href="#animation-vocabulary-set"><code>set</code></a> elements
-each of which defines a specific <a href="#terms-out-of-line-animation">out-of-line animation</a>.</p><p>The <code>animate</code> attribute may be specified by an instance of the following
-element types:</p><ul><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li></ul><p>If specified, the value of an <code>animate</code> attribute must
-adhere to the <code>IDREFS</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
-§ 3.3.10, and, furthermore, each IDREF must reference an <a href="#animation-vocabulary-animate"><code>animate</code></a>
-or <a href="#animation-vocabulary-set"><code>set</code></a> element
-which has a <a href="#animation-vocabulary-animation"><code>animation</code></a> element as an ancestor.</p><p>A given IDREF must not appear more than one time in the value of an <code>animate</code>
-attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See the specific element type definitions that permit use of the
-<code>animate</code> attribute.</p></div></div></div><div class="div2">
-<h3><a id="animation-value-expressions"></a>13.3 Animation Value Expressions</h3><p>Animation attribute values include the use of the following expressions:</p><ul><li><p><a href="#animation-value-animationValue"><b>13.3.1 &lt;animationValue&gt;</b></a></p></li><li><p><a href="#animation-value-animationValueList"><b>13.3.2 &lt;animationValueList&gt;</b></a></p></li><li><p><a href="#animation-value-calcMode"><b>13.3.3 &lt;calcMode&gt;</b></a></p></li><li><p><a href="#animation-value-fill"><b>13.3.4 &lt;fill&gt;</b></a></p></li><li><p><a href="#animation-value-keySplines"><b>13.3.5 &lt;keySplines&gt;</b></a></p></li><li><p><a href="#animation-value-keyTimes"><b>13.3.6 &lt;keyTimes&gt;</b></a></p></li><li><p><a href="#animation-value-repeatCount"><b>13.3.7 &lt;repeatCount&gt;</b></a></p></li></ul><div class="div3">
-<h4><a id="animation-value-animationValue"></a>13.3.1 &lt;animationValue&gt;</h4><p>An &lt;animationValue&gt; expression is used to specify the starting (initial), intermediate,
-or ending (final) of the attribute targeted by the animation.</p><a id="animationValue-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;animationValue&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;animationValue&gt;
-  : string
-</pre></div>
-</td></tr></tbody></table><p>The syntax of an &lt;animationValue&gt; expression must satisfy all syntax
-requirements that apply to the attribute targeted by the animation.</p><table border="1" class="ednote" summary="Editorial note: Improve Syntax of AnimationValue"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Improve Syntax of AnimationValue</b></td><td align="right" valign="top">2014-07-31</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Enhance detail of syntax of &lt;animationValue&gt; in order to prevent appearance of an unquoted or unescaped semicolon,
-which is used as a delimiter between animation values in &lt;animationValueList&gt;.</td></tr></table><p>The semantics of an &lt;animationValue&gt; expression are those defined by
-<a href="#svg11">[SVG 1.1]</a>, §19.2.9.</p></div><div class="div3">
-<h4><a id="animation-value-animationValueList"></a>13.3.2 &lt;animationValueList&gt;</h4><p>An &lt;animationValueList&gt; expression is used to specify a list of animation values that sequentially
-apply to the attribute targeted by the animation, wherein each pair of values is separated by a SEMICOLON (U+003B) character
-optionally surrounded by linear white-space (LWSP) characters.</p><a id="animationValueList-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;animationValueList&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;animationValueList&gt;
-  : <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> [ ";" <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> ]*
-</pre></div>
-</td></tr></tbody></table><p>The syntax of an &lt;animationValue&gt; in an &lt;animationValueList&gt; expression must satisfy all syntax
-requirements that apply to the attribute targeted by the animation.</p><p>The semantics of an &lt;animationValueList&gt; expression are those defined by
-<a href="#svg11">[SVG 1.1]</a>, §19.2.9.</p></div><div class="div3">
-<h4><a id="animation-value-calcMode"></a>13.3.3 &lt;calcMode&gt;</h4><p>A &lt;calcMode&gt; expression is used to control the interpolation mode of the animation.</p><a id="calcMode-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;calcMode&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;calcMode&gt;
-  : "discrete"
-  | "linear"
-  | "spline"
-</pre></div>
-</td></tr></tbody></table><p>The semantics of a &lt;calcMode&gt; expression are those defined by
-<a href="#svg11">[SVG 1.1]</a>, §19.2.9.</p></div><div class="div3">
-<h4><a id="animation-value-fill"></a>13.3.4 &lt;fill&gt;</h4><p>A &lt;fill&gt; expression is used to determine effect of the animation after the active end of the animation.</p><a id="fill-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;fill&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;fill&gt;
-  : "freeze"
-  | "remove"
-</pre></div>
-</td></tr></tbody></table><p>The semantics of a &lt;fill&gt; expression are those defined by
-<a href="#svg11">[SVG 1.1]</a>, §19.2.8.</p></div><div class="div3">
-<h4><a id="animation-value-keySplines"></a>13.3.5 &lt;keySplines&gt;</h4><p>An &lt;keySplines&gt; expression is used to specify a list of Bezier control points that control the pacing of an
-animation, wherein each pair of values is separated by a SEMICOLON (U+003B) character
-optionally surrounded by linear white-space (LWSP) characters.</p><a id="keySplines-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;keySplines&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;keySplines&gt;
-  : control [ lwsp? ";" lwsp? control ]*
-
-control
-  : x1 comma? y1 comma? x2 comma? y2
-
-x1, x2, y1, y2
-  : coordinate
-
-coordinate                                // 0 ≥ <em>value</em> ≥ 1
-  : whole
-  | whole "." fraction
-  | "." fraction
-
-whole, fraction
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-
-comma
-  : ","
-
-lwsp
-  : ( ' ' | '\t' | '\n' | '\r' )+
-</pre></div>
-</td></tr></tbody></table><p>The semantics of a &lt;keySplines&gt; expression are those defined by
-<a href="#svg11">[SVG 1.1]</a>, §19.2.9, as apply to the <code>keySplines</code> attribute.</p></div><div class="div3">
-<h4><a id="animation-value-keyTimes"></a>13.3.6 &lt;keyTimes&gt;</h4><p>An &lt;keyTimes&gt; expression is used to specify a list of relative time values that control the pacing of an
-animation, wherein each pair of values is separated by a SEMICOLON (U+003B) character
-optionally surrounded by linear white-space (LWSP) characters.</p><a id="keyTimes-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;keyTimes&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;keyTimes&gt;
-  : time [ lwsp? ";" lwsp? time ]*
-
-time                                // 0 ≥ <em>value</em> ≥ 1
-  : whole
-  | whole "." fraction
-  | "." fraction
-
-whole, fraction
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+
-
-lwsp
-  : ( ' ' | '\t' | '\n' | '\r' )+
-</pre></div>
-</td></tr></tbody></table><p>The semantics of a &lt;keyTimes&gt; expression are those defined by
-<a href="#svg11">[SVG 1.1]</a>, §19.2.9, as apply to the <code>keyTimes</code> attribute.</p></div><div class="div3">
-<h4><a id="animation-value-repeatCount"></a>13.3.7 &lt;repeatCount&gt;</h4><p>A &lt;repeatCount&gt; expression is used to determine the number of iterations of a repeated animation.</p><a id="repeatCount-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;repeatCount&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;repeatCount&gt;
-  : count
-  | "indefinite"
-
-count:
-  : <a href="#style-value-digit">&lt;digit&gt;</a>+                       // <em>value</em> &gt; 0
-</pre></div>
-</td></tr></tbody></table><p>The semantics of a &lt;repeatCount&gt; expression are those defined by
-<a href="#svg11">[SVG 1.1]</a>, §19.2.8.</p></div></div></div><div class="div1">
-<h2><a id="metadata"></a>14 Metadata</h2><p>This section specifies the <em>metadata</em> matter of the core
-vocabulary catalog, where
-metadata is to be understood as a separable layer of information that applies to
-parameters, content,
-style, layout, timing, and even metadata itself, where the information
-represented by metadata takes one of two forms: (1) metadata defined by this
-specification for standardized use in a <a href="#terms-document-instance">document instance</a>, and (2) arbitrary
-metadata defined outside of the scope of this specification, whose use and
-semantics depend entirely upon an application's use of TTML Content.</p><div class="div2">
-<h3><a id="metadata-element-vocabulary"></a>14.1 Metadata Element Vocabulary</h3><p>The <a href="#metadata-vocabulary-metadata"><b>14.1.1 metadata</b></a> element serves as
-a generic container element for grouping metadata information.</p><p>In addition, the following elements, all defined in the TT Metadata Namespace,
-provide standard representations for metadata that is expected to be commonly
-used in a <a href="#terms-document-instance">document instance</a>:
-</p><ul><li><p><a href="#metadata-vocabulary-actor"><b>14.1.2 ttm:actor</b></a></p></li><li><p><a href="#metadata-vocabulary-agent"><b>14.1.3 ttm:agent</b></a></p></li><li><p><a href="#metadata-vocabulary-copyright"><b>14.1.4 ttm:copyright</b></a></p></li><li><p><a href="#metadata-vocabulary-desc"><b>14.1.5 ttm:desc</b></a></p></li><li><p><a href="#metadata-vocabulary-item"><b>14.1.6 ttm:item</b></a></p></li><li><p><a href="#metadata-vocabulary-name"><b>14.1.7 ttm:name</b></a></p></li><li><p><a href="#metadata-vocabulary-title"><b>14.1.8 ttm:title</b></a></p></li></ul><div class="div3">
-<h4><a id="metadata-vocabulary-metadata"></a>14.1.1 metadata</h4><p>The <code>metadata</code> element functions as a generic container for metadata
-information.</p><p>Metadata information may be expressed with a <code>metadata</code> element by specifying
-(1) one or more metadata attributes or foreign namespace attributes on the <code>metadata</code> element,
-(2) one or more metadata item or foreign namespace child elements,
-(3) one or more <a href="#embedded-content-vocabulary-data"><code>data</code></a> child elements, or
-(4) a combination of the preceding.</p><a id="elt-syntax-metadata"></a><table class="syntax"><caption>XML Representation – Element Information Item: metadata</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;metadata
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute in TT Metadata namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> (<a href="#element-vocab-group-data"><code>Data.class</code></a>|{<em>any element in TT Metadata namespace</em>}|{<em>any element not in any TT namespace</em>})*
-&lt;/metadata&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The meaning of a specific metadata item must be evaluated in the
-context where it appears. The core vocabulary catalog permits an
-arbitrary number of <code>metadata</code> element children on any
-<a href="#terms-content-element">content element</a> type. See specific element
-vocabulary definitions for any constraints that apply to such
-usage.</p></div><p>The use of document metadata is illustrated by the following example.</p><a id="metadata-vocabulary-metadata-example-1"></a><table class="example"><caption>Example Fragment – Document Metadata</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;head&gt;
-  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-    &lt;ttm:title&gt;Document Metadata Example&lt;/ttm:title&gt;
-    &lt;ttm:desc&gt;This document employs document metadata.&lt;/ttm:desc&gt;
-  &lt;/metadata&gt;
-&lt;/head&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p><p>The use of element metadata is illustrated by the following example.</p><a id="metadata-vocabulary-metadata-example-2"></a><table class="example"><caption>Example Fragment – Element Metadata</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;div&gt;
-  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-    &lt;ttm:title&gt;Chapter 6 – Sherlock Holmes Gives a Demonstration&lt;/ttm:title&gt;
-    &lt;ttm:desc&gt;Holmes shows Watson how the murderer entered the window.&lt;/ttm:desc&gt;
-  &lt;/metadata&gt;
-&lt;/div&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p><p>The use of metadata attribute items is illustrated by the following example.</p><a id="metadata-vocabulary-metadata-example-3"></a><table class="example"><caption>Example Fragment – Foreign Metadata Attribute Items</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;div xmlns:ext="http://example.org/ttml#metadata"&gt;
-  &lt;metadata ext:ednote="remove this division prior to publishing"/&gt;
-&lt;/div&gt;
-...
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, a global attribute from a foreign (external)
-namespace is used to express a metadata attribute that applies
-semantically to the containing <code>div</code> element. Note that the
-attribute may also be expressed directly on the <code>div</code> element;
-however, in this case the author wishes to segregate certain metadata
-attributes by expressing them indirectly on <code>metadata</code>
-elements.</p></div><p></p><p>The use of foreign element metadata is illustrated by the following example.</p><a id="metadata-vocabulary-metadata-example-4"></a><table class="example"><caption>Example Fragment – Foreign Element Metadata</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;metadata
-  xmlns:dc="http://purl.org/dc/elements/1.1/"
-  xmlns:dcterms="http://purl.org/dc/terms/"
-  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"&gt;
-  &lt;dc:title&gt;Foreign Element Metadata Example&lt;/dc:title&gt;
-  &lt;dc:description&gt;Express metadata using elements in foreign namespace.&lt;/dc:description&gt;
-  &lt;dc:format xsi:type="dcterms:IMT"&gt;application/ttml+xml&lt;/dc:format&gt;
-&lt;/metadata&gt;
-...
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, a number of elements defined by the Dublin
-Core metadata vocabulary are used to express document level metadata.</p></div><p></p></div><div class="div3">
-<h4><a id="metadata-vocabulary-actor"></a>14.1.2 ttm:actor</h4><p>The <code>ttm:actor</code> element is used to link the definition of a (role-based) character
-agent with another agent that portrays the character.</p><a id="elt-syntax-metadata-actor"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:actor</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttm:actor
-  <span class="reqattr">agent</span> = IDREF
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> EMPTY
-&lt;/ttm:actor&gt;
-</pre></div>
-</td></tr></tbody></table><p>The <code>agent</code> attribute of a <code>ttm:actor</code> element must
-reference a <em>significant</em> <code>ttm:agent</code> element that denotes the agent
-acting the part of a character.</p><p>An example of the <code>ttm:actor</code> element is shown above in
-<a href="#metadata-vocabulary-agent-example-1"><b>Example Fragment – Agent Metadata</b></a>.</p></div><div class="div3">
-<h4><a id="metadata-vocabulary-agent"></a>14.1.3 ttm:agent</h4><p>The <code>ttm:agent</code> element is used to define an agent for the purpose of associating
-content information with an agent who is involved in the production or expression of that content.</p><p>The <code>ttm:agent</code> element accepts as its children zero or more <code>ttm:name</code> elements followed by
-zero or one <code>ttm:actor</code> element.</p><p>At least one <code>ttm:name</code> element child should be specified that expresses a name for the
-agent, whether it be the name of a person, character, group, or organization.</p><a id="elt-syntax-metadata-agent"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:agent</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttm:agent
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <span class="reqattr">type</span> = (<em>person</em>|<em>character</em>|<em>group</em>|<em>organization</em>|<em>other</em>)
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#metadata-vocabulary-name">ttm:name</a>*, <a href="#metadata-vocabulary-actor">ttm:actor</a>?
-&lt;/ttm:agent&gt;
-</pre></div>
-</td></tr></tbody></table><p>A <code>type</code> attribute must be specified on each <code>ttm:agent</code> element, and,
-if specified, must have one of the following values:</p><ul><li><p><code>person</code></p></li><li><p><code>character</code></p></li><li><p><code>group</code></p></li><li><p><code>organization</code></p></li><li><p><code>other</code></p></li></ul><p>If the value of the <code>type</code> attribute is <code>character</code>, then the
-<code>ttm:agent</code> element instance should specify a <code>ttm:actor</code> child that
-specifies the agent that plays the role of the actor.</p><p>A <code>ttm:agent</code> metadata item is considered to be significant only
-when specified as a child of the <code>head</code> element or as a child of a
-<code>metadata</code> element child of the <code>head</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <code>ttm:agent</code> element instance is typically referenced using a <code>ttm:agent</code>
-attribute on a <a href="#terms-content-element">content element</a> type.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>If a character agent is played by multiple actors, then multiple character
-agents may be specified (and referenced) wherein different definitions of the
-character specify different actors.</p></div><p>The use of agent metadata is illustrated by the following example.</p><a id="metadata-vocabulary-agent-example-1"></a><table class="example"><caption>Example Fragment – Agent Metadata</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;tt xml:lang="en" xmlns="http://www.w3.org/ns/ttml" xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
-  &lt;head&gt;
-    <span class="strong">&lt;ttm:agent xml:id="connery" type="person"&gt;</span>
-      &lt;ttm:name type="family"&gt;Connery&lt;/ttm:name&gt;
-      &lt;ttm:name type="given"&gt;Thomas Sean&lt;/ttm:name&gt;
-      &lt;ttm:name type="alias"&gt;Sean&lt;/ttm:name&gt;
-      &lt;ttm:name type="full"&gt;Sir Thomas Sean Connery&lt;/ttm:name&gt;
-    <span class="strong">&lt;/ttm:agent&gt;</span>
-    <span class="strong">&lt;ttm:agent xml:id="bond" type="character"&gt;</span>
-      &lt;ttm:name type="family"&gt;Bond&lt;/ttm:name&gt;
-      &lt;ttm:name type="given"&gt;James&lt;/ttm:name&gt;
-      &lt;ttm:name type="alias"&gt;007&lt;/ttm:name&gt;
-      &lt;ttm:actor agent="connery"/&gt;
-    <span class="strong">&lt;/ttm:agent&gt;</span>
-  &lt;/head&gt;
-  &lt;body&gt;
-    &lt;div&gt;
-      ...  
-      &lt;p <span class="strong">ttm:agent="bond"</span>&gt;I travel, a sort of licensed troubleshooter.&lt;/p&gt;
-      ...  
-    &lt;/div&gt;
-  &lt;/body&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, two agents, a real (person) agent, Sean
-Connery, and a fictitious (character) agent, James Bond, are defined,
-where the latter is linked to the former by means of the a
-<code>ttm:actor</code> element. A reference is then made from content (the
-<code>p</code> element) to the character agent associated with
-(responsible for producing) that content. Note that in this example
-the <code>ttm:agent</code> metadata items are specified as immediate
-children of the document's <code>head</code> element rather than being
-placed in a container <code>metadata</code> element.</p></div></div><div class="div3">
-<h4><a id="metadata-vocabulary-copyright"></a>14.1.4 ttm:copyright</h4><p>The <code>ttm:copyright</code> element is used to express a human-readable copyright that
-applies to some scoping level.</p><p>A copyright statement that applies to a document as a whole should appear as a
-child of the <code>head</code> element.</p><a id="elt-syntax-metadata-copyright"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:copyright</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttm:copyright
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA
-&lt;/ttm:copyright&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>No specific use of the <code>ttm:copyright</code> element is defined by this specification.</p></div></div><div class="div3">
-<h4><a id="metadata-vocabulary-desc"></a>14.1.5 ttm:desc</h4><p>The <code>ttm:desc</code> element is used to express a human-readable description of
-a specific element instance.</p><a id="elt-syntax-metadata-desc"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:desc</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttm:desc
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA
-&lt;/ttm:desc&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>No specific use of the <code>ttm:desc</code> element is defined by this specification.</p></div><p>Examples of the <code>ttm:desc</code> element are shown above in
-<a href="#metadata-vocabulary-metadata-example-1"><b>Example Fragment – Document Metadata</b></a> and
-<a href="#metadata-vocabulary-metadata-example-2"><b>Example Fragment – Element Metadata</b></a>.</p></div><div class="div3">
-<h4><a id="metadata-vocabulary-item"></a>14.1.6 ttm:item</h4><p>The <code>ttm:item</code> element is used to express arbitrary named metadata items.</p><p>The <code>ttm:item</code> element accepts one of the following two content models:
-(1) one or more text nodes (i.e., <code>#PCDATA</code>) or
-(2) zero or more nested <a href="#metadata-vocabulary-item">ttm:item</a> elements.</p><a id="elt-syntax-metadata-item"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:item</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttm:item
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <span class="reqattr">name</span> = <a href="#metadata-value-item-name">&lt;item-name&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA | <a href="#metadata-vocabulary-item">ttm:item</a>*
-&lt;/ttm:item&gt;
-</pre></div>
-</td></tr></tbody></table><p>A <code>name</code> attribute must be specified to identify the name of the item, the value of which must adhere to
-an <a href="#metadata-value-item-name">&lt;item-name&gt;</a> value expression.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>No general constraint is placed on the appearance of multiple named metadata items that specify the same name; however,
-the definition of a specific named item may further constrain the context of use as well as the potential appearance of multiple items that share the same name.</p></div><p>The value of a named metadata item is
-(1) empty if the element has no child text or element nodes,
-(2) the character content of the <code>ttm:item</code> element when that element's children consists solely of text nodes, or
-(3) a collection of named metadata sub-items.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The definition of a particular named item will typically constrain the set of permitted values. Furthermore, it may
-specify that a particular value is implied in the absence of a specified value.</p></div><p>The use of a named metadata item is illustrated by the following example, which shows the use of a named metadata item
-in order to associate a <a href="#terms-simple-data-embedding">simple data embedding</a> with an original file name.</p><a id="metadata-vocabulary-item-example-1"></a><table class="example"><caption>Example Fragment – Named Metadata Item</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-...
-&lt;image&gt;
-  &lt;source&gt;
-    &lt;data type="image/png"&gt;
-      <span class="strong">&lt;ttm:item name="originalFileName" xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;image.png&lt;/ttm:item&gt;</span>
-      &lt;chunk length="119"&gt;
-        iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
-        YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
-      &lt;/chunk&gt;
-    &lt;/data&gt;
-  &lt;/source&gt;
-&lt;/image&gt;
-...
-</pre></div>
-</td></tr></tbody></table><p></p><div class="note"><p class="prefix"><b>Note:</b></p><p>The above example makes use of a single <a href="#embedded-content-vocabulary-chunk">chunk</a> element in order
-to include a <code>ttm:item</code> element as a child of the <a href="#embedded-content-vocabulary-data">data</a> element;
-i.e., if the encoded image bytes had been included directly as #PCDATA in the <a href="#embedded-content-vocabulary-data">data</a> element,
-then it would not have been possible to include the <code>ttm:item</code> child element. See the supported content models on the
-<a href="#embedded-content-vocabulary-data">data</a> element for more information.</p></div></div><div class="div3">
-<h4><a id="metadata-vocabulary-name"></a>14.1.7 ttm:name</h4><p>The <code>ttm:name</code> element is used to specify a name of a person, character,
-group, or organization.</p><a id="elt-syntax-metadata-name"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:name</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttm:name
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <span class="reqattr">type</span> = (<em>full</em>|<em>family</em>|<em>given</em>|<em>alias</em>|<em>other</em>)
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA
-&lt;/ttm:name&gt;
-</pre></div>
-</td></tr></tbody></table><p>A <code>type</code> attribute must be specified on each <code>ttm:name</code> element, and,
-if specified, must have one of the following values:</p><ul><li><p><code>full</code></p></li><li><p><code>family</code></p></li><li><p><code>given</code></p></li><li><p><code>alias</code></p></li><li><p><code>other</code></p></li></ul><p>The relationship between the type of a name and the syntactic expression of the name
-is not defined by this specification.</p><p>Two examples of the <code>ttm:name</code> element are shown above in
-<a href="#metadata-vocabulary-agent-example-1"><b>Example Fragment – Agent Metadata</b></a>.</p></div><div class="div3">
-<h4><a id="metadata-vocabulary-title"></a>14.1.8 ttm:title</h4><p>The <code>ttm:title</code> element is used to express a human-readable title of
-a specific element instance.</p><a id="elt-syntax-metadata-title"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:title</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;ttm:title
-  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
-  <a href="#content-attribute-xml-id">xml:id</a> = ID
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> #PCDATA
-&lt;/ttm:title&gt;
-</pre></div>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>No specific use of the <code>ttm:title</code> element is defined by this specification.</p></div><p>Examples of the <code>ttm:title</code> element are shown above in
-<a href="#metadata-vocabulary-metadata-example-1"><b>Example Fragment – Document Metadata</b></a> and
-<a href="#metadata-vocabulary-metadata-example-2"><b>Example Fragment – Element Metadata</b></a>.</p></div></div><div class="div2">
-<h3><a id="metadata-attribute-vocabulary"></a>14.2 Metadata Attribute Vocabulary</h3><p>This section specifies the following attributes in the TT Metadata Namespace
-for use with the <code>metadata</code> element and with certain
-<a href="#terms-content-element">content element</a> types:</p><ul><li><p><a href="#metadata-attribute-agent"><b>14.2.1 ttm:agent</b></a></p></li><li><p><a href="#metadata-attribute-role"><b>14.2.2 ttm:role</b></a></p></li></ul><div class="issue"><p class="prefix"><a id="issue-358"></a><b>Issue (issue-358):</b></p><p class="prefix"><b>Document Sequencing</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/358">http://www.w3.org/AudioVideo/TT/tracker/issues/358</a></p><p>Add <code>ttm:sequenceIdentifier</code> or <code>ttm:sequenceNumber</code> or both if unavoidable.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><div class="issue"><p class="prefix"><a id="issue-361"></a><b>Issue (issue-361):</b></p><p class="prefix"><b>Media Timestamp Correlation</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/361">http://www.w3.org/AudioVideo/TT/tracker/issues/361</a></p><p>Add <code>ttm:mediaTimestamp</code> to support media synchronization.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Only certain metadata item attributes may be used with <a href="#terms-content-element">content element</a>. See
-the definitions of <a href="#terms-content-element">content elements</a> to determine permissible usage.</p></div><div class="div3">
-<h4><a id="metadata-attribute-agent"></a>14.2.1 ttm:agent</h4><p>The <code>ttm:agent</code> attribute takes an <code>IDREFS</code>
-value, and is used with certain <a href="#terms-content-element">content elements</a> to designate the
-agents that perform or are
-involved in the performance of the content.</p><p>If specified, a <code>ttm:agent</code> attribute must reference <em>significant</em>
-<code>ttm:agent</code> element instances.</p><p>The same IDREF, <em>ID</em>, should not appear more than once in the value of a <code>ttm:agent</code> attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This constraint is intended to discourage the use of redundant agent references.</p></div><p>An example of the <code>ttm:agent</code> attribute is shown above in
-<a href="#metadata-vocabulary-agent-example-1"><b>Example Fragment – Agent Metadata</b></a>.</p></div><div class="div3">
-<h4><a id="metadata-attribute-role"></a>14.2.2 ttm:role</h4><p>The <code>ttm:role</code> attribute may be used by a content author
-to express
-the roles, functions, or characteristics
-of some <a href="#terms-content-element">content element</a> that is so labeled.</p><div class="issue"><p class="prefix"><a id="issue-25"></a><b>Issue (issue-25):</b></p><p class="prefix"><b>Parameterized Roles</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/25">http://www.w3.org/AudioVideo/TT/tracker/issues/25</a></p><p>Consider supporting parameterized roles to increase CEA 708 interoperability.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If specified, the value of this attribute must adhere to the following
-syntax, where
-the syntactic element <em>S</em> must adhere to production
-[3] <code>S</code> as defined by <a href="#xml10">[XML 1.0]</a>&nbsp;§
-2.3:</p><a id="metadata-attribute-role-syntax"></a><table class="syntax"><caption>Syntax Representation – ttm:role</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-ttm:role
-  role ( <em>S</em> role )*
-
-role
-  : "action"
-  | "caption"
-  | "description"
-  | "dialog"
-  | "expletive"
-  | "kinesic"
-  | "lyrics"
-  | "music"
-  | "narration"
-  | "quality"
-  | "sound"
-  | "source"
-  | "suppressed"
-  | "reproduction"
-  | "thought"
-  | "title"
-  | "transcription"
-  | extension-role
-
-extension-role
-  : "x-" token-char+
-
-token-char
-  : { XML NameChar }    // XML 1.1 Production [4a]
-</pre></div>
-</td></tr></tbody></table><p>The same <code>role</code> token, <em>R</em>, should not appear more than once in the value of a <code>ttm:role</code> attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This constraint is intended to discourage the use of redundant role tokens.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>All values of <code>ttm:role</code> that do not start with the prefix
-<code>x-</code> are reserved for future standardization.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>If using a custom <code>x-</code> prefixed form of <code>ttm:role</code>, it
-is recommended that an organization unique infix be used as well in order to
-prevent collisions. For example, <code>x-example-org-custom-role</code>. Furthermore,
-a registry for role values is available at
-<a href="http://www.w3.org/wiki/TTML/RoleRegistry">http://www.w3.org/wiki/TTML/RoleRegistry</a>
-in order to promote interoperability and collision avoidance.</p></div></div></div><div class="div2">
-<h3><a id="metadata-value-expressions"></a>14.3 Metadata Value Expressions</h3><p>Metadata vocabulary may make use of the following expressions:</p><ul><li><p><a href="#metadata-value-item-name"><b>14.3.1 &lt;item-name&gt;</b></a></p></li></ul><div class="div3">
-<h4><a id="metadata-value-item-name"></a>14.3.1 &lt;item-name&gt;</h4><p>An &lt;item-name&gt; expression is used to specify the name of a metadata item expressed with a
-<a href="#metadata-vocabulary-item">ttm:item</a> element.</p><a id="item-name-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;item-name&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;item-name&gt;
-  : <a href="#metadata-value-named-item">&lt;named-item&gt;</a>
-  | <a href="http://www.w3.org/TR/xmlschema-2/#QName">xsd:QName</a>
-</pre></div>
-</td></tr></tbody></table><p>If an item name expression takes the form of a qualified name (<a href="http://www.w3.org/TR/xmlschema-2/#QName">xsd:QName</a>), 
-then the prefix of that qualified name must have been declared in a namespace declaration as specified by <a href="#xmlns10">[XML Namespaces 1.0]</a>.</p><p>All values of &lt;item-name&gt; that do not take the form of qualified name (<a href="http://www.w3.org/TR/xmlschema-2/#QName">xsd:QName</a>)
-are reserved for future standardization by the W3C.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>It is intended that all item names defined by this specification are unqualified (without a prefix), whereas those defined by
-external specifications are qualified (with a prefix).</p></div></div><div class="div3">
-<h4><a id="metadata-value-named-item"></a>14.3.2 &lt;named-item&gt;</h4><p>A &lt;named-item&gt; value is one of an enumerated collection of named metadata items associated with a value by
-a <a href="#metadata-vocabulary-item"><code>ttm:item</code></a> element.</p><a id="named-item-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;named-item&gt;</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;named-item&gt;
-  : cea608CaptionService
-  | cea608Channel
-  | cea608ContentAdvisory
-  | cea608CopyAndRedistributionControl
-  | cea608FieldStart
-  | cea608ProgramName
-  | cea608ProgramType
-  | cea708EasyReader
-  | cea708FCCMinimum
-  | cea708ServiceNumber
-  | cea708TransformMode
-  | cea708TransformOrigin
-  | cea708TransformTimingThreshold
-  | creationCountryOfOrigin
-  | creationDate
-  | creationSystem
-  | editor
-  | editorContact
-  | maximumCharactersPerRow
-  | originalEpisodeTitle
-  | originalFileName
-  | originalProgramTitle
-  | publisher
-  | readingSpeed
-  | revisionDate
-  | revisionNumber
-  | sourceFormat
-  | subtitleCount
-  | subtitleReferenceCode
-  | targetAspectRatio
-  | targetActiveFormatDescriptor
-  | targetBarData
-  | targetFormat
-  | translatedEpisodeTitle
-  | translatedProgramTitle
-  | translator
-  | translatorContact
-</pre></div>
-</td></tr></tbody></table><p></p><div class="issue"><p class="prefix"><a id="issue-328"></a><b>Issue (issue-328):</b></p><p class="prefix"><b>Alternate Text Metadata</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/328">http://www.w3.org/AudioVideo/TT/tracker/issues/328</a></p><p>Add named item to handle <code>ittm:altText</code>.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><table border="1" class="ednote" summary="Editorial note: Elaborate Named Items"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Elaborate Named Items</b></td><td align="right" valign="top">2014-11-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Further specify the value syntax of certain named items, e.g., by adding external document references (CEA608) or by defining specific value syntax.</td></tr></table><dl><dt class="label"><a id="named-item-cea608CaptionService"></a><code>cea608CaptionService</code></dt><dd><p>A string that expresses the field and channel mapping of a CEA-608 caption service, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608Channel"></a><code>cea608Channel</code></dt><dd><p>A string that expresses the channel code of a CEA-608 caption service, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608ContentAdvisory"></a><code>cea608ContentAdvisory</code></dt><dd><p>A string that expresses the content advisory packet information of a CEA-608 caption service, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608CopyAndRedistributionControl"></a><code>cea608CopyAndRedistributionControl</code></dt><dd><p>A string that expresses the copy and redistribution control packet information of a CEA-608 caption service, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608FieldStart"></a><code>cea608FieldStart</code></dt><dd><p>An integer that expresses the field start of a CEA-608 caption service, where the value
-is either 1 or 2.</p></dd><dt class="label"><a id="named-item-cea608ProgramName"></a><code>cea608ProgramName</code></dt><dd><p>A string that expresses the program name of a CEA-608 caption service, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608ProgramType"></a><code>cea608ProgramType</code></dt><dd><p>A string that expresses the program type code of a CEA-608 caption service, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea708EasyReader"></a><code>cea708EasyReader</code></dt><dd><p>A boolean that expresses whether a CEA-708 caption service is characterized for use with an easy reader, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:boolean</a>.</p></dd><dt class="label"><a id="named-item-cea708FCCMinimum"></a><code>cea708FCCMinimum</code></dt><dd><p>A boolean that expresses whether a CEA-708 caption service is characterized as conforming to minimum FCC decoder requirements, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:boolean</a>.</p></dd><dt class="label"><a id="named-item-cea708ServiceNumber"></a><code>cea708ServiceNumber</code></dt><dd><p>An integer that expresses the service number of a CEA-708 caption service, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</a> and is less than 32.</p></dd><dt class="label"><a id="named-item-cea708TransformMode"></a><code>cea708TransformMode</code></dt><dd><p>One of the token values <code>enhanced</code> or <code>preserved</code>.</p></dd><dt class="label"><a id="named-item-cea708TransformOrigin"></a><code>cea708TransformOrigin</code></dt><dd><p>Either the token <code>none</code> or an <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
-where the latter expresses a CEA-708 transformation source format.</p></dd><dt class="label"><a id="named-item-cea708TransformTimingThreshold"></a><code>cea708TransformTimingThreshold</code></dt><dd><p>A real number that expresses a threshold parameter used to suppress the inclusion of temporary timed states when
-transforming amongst a CEA-708 caption service and a <a href="#terms-timed-text-content-document">timed text content document</a>,
-where the value adheres to <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:float</a>.</p></dd><dt class="label"><a id="named-item-creationCountryOfOrigin"></a><code>creationCountryOfOrigin</code></dt><dd><p>A string that expresses a the country or origin code associated with this document, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-creationDate"></a><code>creationDate</code></dt><dd><p>A date that expresses the creation date of this document, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#date">xsd:date</a>.</p></dd><dt class="label"><a id="named-item-creationSystem"></a><code>creationSystem</code></dt><dd><p>A free form string expressing the software and version used to create the document, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-editor"></a><code>editor</code></dt><dd><p>A string that expresses the name of one or more editors, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-editorContact"></a><code>editorContact</code></dt><dd><p>A string that expresses the contact details of one or more editors, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-maximumCharactersPerRow"></a><code>maximumCharactersPerRow</code></dt><dd><p>A non-negative integer that expresses the maximum number of characters per row (line) used in this document, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>.</p></dd><dt class="label"><a id="named-item-originalEpisodeTitle"></a><code>originalEpisodeTitle</code></dt><dd><p>A string that expresses the episode title in the original language, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-originalFileName"></a><code>originalFileName</code></dt><dd><p>A string that expresses the original file name of a <a href="#terms-data-resource">data resource</a>, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p><p>A <code>originalFileName</code> item may specified as a descendant element of a <a href="#embedded-content-vocabulary-data">data</a> element
-in order to associate the <a href="#terms-data-resource">data resource</a> represented by that <a href="#embedded-content-vocabulary-data">data</a> element
-with an original file name.</p></dd><dt class="label"><a id="named-item-originalProgramTitle"></a><code>originalProgramTitle</code></dt><dd><p>A string that expresses the program title in the original language, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-publisher"></a><code>publisher</code></dt><dd><p>A string that expresses the name of one or more publishers, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-readingSpeed"></a><code>readingSpeed</code></dt><dd><p>An integer that expresses the reading speed in words per minute, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</a>.</p></dd><dt class="label"><a id="named-item-revisionDate"></a><code>revisionDate</code></dt><dd><p>A date that expresses the last revision date of this document, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#date">xsd:date</a>.</p></dd><dt class="label"><a id="named-item-revisionNumber"></a><code>revisionNumber</code></dt><dd><p>A non-negative integer that expresses the revision number of this document, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>.</p></dd><dt class="label"><a id="named-item-sourceFormat"></a><code>sourceFormat</code></dt><dd><p>A string that expresses the source subtitle or caption format from which the <a href="#terms-enclosing-document-instance">enclosing document instance</a>
-was transformed, where the value adheres to either <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
-or <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>.</p></dd><dt class="label"><a id="named-item-subtitleCount"></a><code>subtitleCount</code></dt><dd><p>A non-negative integer that expresses the number of subtitles (captions) in this document, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>.</p></dd><dt class="label"><a id="named-item-subtitleReferenceCode"></a><code>subtitleReferenceCode</code></dt><dd><p>A string that expresses a subtitle reference code, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-targetAspectRatio"></a><code>targetAspectRatio</code></dt><dd><p>A string that expresses the target video's aspect ratio, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-targetActiveFormatDescriptor"></a><code>targetActiveFormatDescriptor</code></dt><dd><p>A string that expresses the target video's active format descriptor, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-targetBarData"></a><code>targetBarData</code></dt><dd><p>A string that expresses the target video's bar data, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-targetFormat"></a><code>targetFormat</code></dt><dd><p>A string that expresses the target subtitle or caption format to which the <a href="#terms-enclosing-document-instance">enclosing document instance</a>
-is intended to be transformed, where the value adheres to either <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
-or <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>.</p></dd><dt class="label"><a id="named-item-translatedEpisodeTitle"></a><code>translatedEpisodeTitle</code></dt><dd><p>A string that expresses the episode title in the translated (local) language, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-translatedProgramTitle"></a><code>translatedProgramTitle</code></dt><dd><p>A string that expresses the program title in the translated (local) language, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-translator"></a><code>translator</code></dt><dd><p>A string that expresses the name of one or more translators, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-translatorContact"></a><code>translatorContact</code></dt><dd><p>A string that expresses the contact details of one or more translators, where the value
-adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd></dl></div></div></div></div><div class="back"><div class="div1">
-<h2><a id="concrete-encoding"></a>A Concrete Encoding</h2><p><em>This appendix is normative.</em></p><p>In the absence of other requirements, a <a href="#terms-document-instance">document instance</a> should be concretely encoded as a
-well-formed XML 1.0 <a href="#xml10">[XML 1.0]</a> document using the UTF-8 character encoding.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When using XML 1.0 <a href="#xml10">[XML 1.0]</a> as the concrete encoding of TTML, only the following named character entities are defined:
-<code>&amp;amp;</code>, <code>&amp;apos;</code>, <code>&amp;gt;</code>, <code>&amp;lt;</code>, and <code>&amp;quot;</code>.</p></div><div class="issue"><p class="prefix"><a id="issue-360"></a><b>Issue (issue-360):</b></p><p class="prefix"><b>Support Content Encoding</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/360">http://www.w3.org/AudioVideo/TT/tracker/issues/360</a></p><p>Specify preference to use of gzip content encoding for compressed delivery in the case that client indicates it accepts encoding.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div></div><div class="div1">
-<h2><a id="reduced-infoset"></a>B Reduced XML Infoset</h2><p><em>This appendix is normative.</em></p><p>For the purposes of this specification, a <a href="#terms-reduced-xml-infoset">reduced xml infoset</a> is
-an XML Information Set <a href="#infoset">[XML InfoSet]</a> that consists of only the following information items
-and information item properties:</p><div class="div2">
-<h3><a id="reduced-infoset-document"></a>B.1 Document Information Item</h3><ul><li><p><code>[document element]</code></p></li></ul></div><div class="div2">
-<h3><a id="reduced-infoset-element"></a>B.2 Element Information Item</h3><ul><li><p><code>[namespace URI]</code></p></li><li><p><code>[local name]</code></p></li><li><p><code>[children]</code></p></li><li><p><code>[attributes]</code></p></li></ul><p>Child information items <code>[children]</code> are reduced to only
-<a href="#terms-element-information-item">element information items</a> and
-<a href="#terms-character-information-item">character information items</a>.</p></div><div class="div2">
-<h3><a id="reduced-infoset-attribute"></a>B.3 Attribute Information Item</h3><ul><li><p><code>[namespace URI]</code></p></li><li><p><code>[local name]</code></p></li><li><p><code>[normalized value]</code></p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>See also <a href="#terms-attribute-information-item">attribute information item</a>.</p></div></div><div class="div2">
-<h3><a id="reduced-infoset-character"></a>B.4 Character Information Item</h3><ul><li><p><code>[character code]</code></p></li></ul><p>Contiguous character information items are not required to be represented distinctly,
-but may be aggregated (chunked) into a sequence of character codes (i.e., a character string).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See also <a href="#terms-character-information-item">character information item</a>.</p></div></div></div><div class="div1">
-<h2><a id="schemas"></a>C Schemas</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the following schemas for use with
-<a href="#terms-document-instance">document instances</a>:</p><ul><li><p>Relax NG, Compact Syntax (RNC) Schema</p></li><li><p>XML Schema Definition (XSD) Schema</p></li></ul><p>In any case where a schema specified by this appendix differs from the
-normative definitions of document type, element type, or attribute type
-as defined by the body of this specification, then the body of this
-specification takes precedence.</p><div class="div2">
-<h3><a id="ttml-schema-rnc"></a>C.1 Relax NG Compact (RNC) Schema</h3><p>A Relax NG Compact Syntax (RNC) <a href="#rng">[RELAX NG]</a> based schema
-for TTML Content is available at <a href="rnc/schema.zip">ZIP
-Archive</a>. This schema is to be considered non-normative for the purpose of defining the validity
-of Timed Text Markup Language content as defined by this specification.
-In particular, the formal validity of TTML Content
-is defined by <a href="#conformance-content"><b>3.1 Document Conformance</b></a>.</p></div><div class="div2">
-<h3><a id="ttml-schema-xsd"></a>C.2 XML Schema Definition (XSD) Schema</h3><p>A W3C XML Schema Definition (XSD) <a href="#xsd-1">[XML Schema Part 1]</a> based schema
-for TTML Content is available at <a href="xsd/schema.zip">ZIP
-Archive</a>. This schema is to be considered non-normative for the purpose of defining the validity
-of Timed Text Markup Language content as defined by this specification.
-In particular, the formal validity of TTML Content
-is defined by <a href="#conformance-content"><b>3.1 Document Conformance</b></a>.</p></div></div><div class="div1">
-<h2><a id="media-types-registration"></a>D Media Type Registration</h2><p><em>This appendix is normative.</em></p><div class="issue"><p class="prefix"><a id="issue-352"></a><b>Issue (issue-352):</b></p><p class="prefix"><b>Restore Media Type Registration</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/352">http://www.w3.org/AudioVideo/TT/tracker/issues/352</a></p><p>Restore and update media type registration for IANA update.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><div class="issue"><p class="prefix"><a id="issue-351"></a><b>Issue (issue-351):</b></p><p class="prefix"><b>Processor Profiles Parameter</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/351">http://www.w3.org/AudioVideo/TT/tracker/issues/351</a></p><p>Add definition of <code>processorProfiles</code> media type parameter.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div></div><div class="div1">
-<h2><a id="features"></a>E Features</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies (1) a set of feature designations, each of which
-labels one or more syntactic and/or semantic features defined by this
-specification, and (2) for each designated feature, whether the feature is mandatory
-or optional for a transformation or <a href="#terms-presentation-processor">presentation processor</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A TTML processor is said to <em>implement the transformation semantics</em> or
-<em>implement the presentation semantics</em> of feature designation <em>F</em>
-if it satisfies the requirements of this appendix with respect to the definition of
-feature designation <em>F</em> as pertains to transformation or
-presentation processing, respectively.</p></div><div class="div2">
-<h3><a id="feature-designations"></a>E.1 Feature Designations</h3><p>A feature designation is expressed as a string that adheres to the following
-form:</p><div class="exampleInner"><pre>
-feature-designation
-  : feature-namespace designation
-
-feature-namespace
-  : <em>TT Feature Namespace</em>                    // http://www.w3.org/ns/ttml/feature/
-
-designation
-  : "#" token-char+
-
-token-char
-  : { XML NameChar }                        // XML 1.1 Production [4a]
-</pre></div><p>All values of <code>feature-designation</code> not defined by this specification are reserved
-for future standardization.</p><p>The following sub-sections define all feature designations, expressed
-as relative URIs (fragment identifiers) with respect to the 
-TT Feature Namespace base URI.</p><table border="1" class="ednote" summary="Editorial note: #animation subset features"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: #animation subset features</b></td><td align="right" valign="top">2013-08-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add fine grained subset features of #animation.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: #inline-region features"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: #inline-region features</b></td><td align="right" valign="top">2014-03-27</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add feature(s) associated with support for explicit and implied inline regions.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: New style property features"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: New style property features</b></td><td align="right" valign="top">2014-10-02</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add features to cover new style properties: border, fontVariantPosition, ruby, rubyAlign, rubyOffset, rubyPosition, textOrientation, etc.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: New embedded content features"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: New embedded content features</b></td><td align="right" valign="top">2014-11-27</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add features to cover new embedded content features: audio, data, font, image, etc.</td></tr></table><div class="div3">
-<h4><a id="feature-animation"></a>E.1.1 #animation</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#animation</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <a href="#animation"><b>13 Animation</b></a>:</p><ul><li><p><a href="#animation-vocabulary-animation"><code>animation</code></a></p></li><li><p><a href="#animation-vocabulary-animate"><code>animate</code></a></p></li><li><p><a href="#animation-vocabulary-set"><code>set</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#animation</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p></div><div class="div3">
-<h4><a id="feature-backgroundColor"></a>E.1.2 #backgroundColor</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#backgroundColor</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#backgroundColor</code> feature if it (1) implements presentation semantic support
-for the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
-attribute
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space.</p></div><div class="div3">
-<h4><a id="feature-backgroundColor-block"></a>E.1.3 #backgroundColor-block</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#backgroundColor-block</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
-attribute when applied to a content element that would generate a
-block area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#backgroundColor-block</code> feature if it (1) implements presentation semantic
-support for the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
-attribute when applied to a content element that generates a
-block area
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space.</p></div><div class="div3">
-<h4><a id="feature-backgroundColor-inline"></a>E.1.4 #backgroundColor-inline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#backgroundColor-inline</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
-attribute when applied to a content element that would generate an
-inline area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#backgroundColor-inline</code> feature if it (1) implements presentation semantic
-support for the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
-attribute when applied to a content element that generates an
-inline area
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space.</p></div><div class="div3">
-<h4><a id="feature-backgroundColor-region"></a>E.1.5 #backgroundColor-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#backgroundColor-region</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
-attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#backgroundColor-region</code> feature if it (1) implements presentation semantic
-support for the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
-attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space
-.</p></div><div class="div3">
-<h4><a id="feature-bidi"></a>E.1.6 #bidi</h4><p>A TTML processor supports the <code>#bidi</code> feature if it
-supports the following features:</p><ul><li><p><a href="#feature-direction"><code>#direction</code></a></p></li><li><p><a href="#feature-unicodeBidi"><code>#unicodeBidi</code></a></p></li><li><p><a href="#feature-writingMode-horizontal"><code>#writingMode-horizontal</code></a></p></li></ul></div><div class="div3">
-<h4><a id="feature-border"></a>E.1.7 #border</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#border</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-border"><code>tts:border</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#border</code> feature if it (1) implements presentation semantic support
-for the <a href="#style-attribute-border"><code>tts:border</code></a>
-attribute
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of border colors,
-including all primary and secondary colors of the SRGB color space.</p><table border="1" class="ednote" summary="Editorial note: Features related to tts:border"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Features related to tts:border</b></td><td align="right" valign="top">2013-08-23</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add additional border related features.</td></tr></table></div><div class="div3">
-<h4><a id="feature-cellResolution"></a>E.1.8 #cellResolution</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#cellResolution</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-cellResolution"><code>ttp:cellResolution</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#cellResolution</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-cellResolution"><code>ttp:cellResolution</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-clockMode"></a>E.1.9 #clockMode</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#clockMode</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#clockMode</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-clockMode-gps"></a>E.1.10 #clockMode-gps</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#clockMode-gps</code> feature if it recognizes and is capable of
-transforming the <code>gps</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#clockMode-gps</code> feature if it implements presentation semantic support
-for the <code>gps</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-clockMode-local"></a>E.1.11 #clockMode-local</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#clockMode-local</code> feature if it recognizes and is capable of
-transforming the <code>local</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#clockMode-local</code> feature if it implements presentation semantic support
-for the <code>local</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-clockMode-utc"></a>E.1.12 #clockMode-utc</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#clockMode-utc</code> feature if it recognizes and is capable of
-transforming the <code>utc</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#clockMode-utc</code> feature if it implements presentation semantic support
-for the <code>utc</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-color"></a>E.1.13 #color</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#color</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-color"><code>tts:color</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#color</code> feature if it (1) implements presentation semantic support
-for the <a href="#style-attribute-color"><code>tts:color</code></a>
-attribute
-and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least sixteen (16) values of color,
-including all primary and secondary colors of the SRGB color space.</p></div><div class="div3">
-<h4><a id="feature-content"></a>E.1.14 #content</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#content</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <a href="#content"><b>8 Content</b></a>:</p><ul><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#content</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p></div><div class="div3">
-<h4><a id="feature-core"></a>E.1.15 #core</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#core</code>
-feature if it recognizes and is capable of transforming the following
-core attributes vocabulary defined by <a href="#content"><b>8 Content</b></a>:</p><ul><li><p><a href="#content-attribute-xml-id">@<code>xml:id</code></a></p></li><li><p><a href="#content-attribute-xml-id">@<code>xml:lang</code></a></p></li><li><p><a href="#content-attribute-xml-id">@<code>xml:space</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#core</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p></div><div class="div3">
-<h4><a id="feature-direction"></a>E.1.16 #direction</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#direction</code> feature if it recognizes and is capable of
-transforming all defined values of the <a href="#style-attribute-direction"><code>tts:direction</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#direction</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-direction"><code>tts:direction</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-display"></a>E.1.17 #display</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#display</code> feature if it recognizes and is capable of
-transforming all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#display</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-display-block"></a>E.1.18 #display-block</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#display-block</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
-attribute when applied to a content element that would generate a
-block area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#display-block</code> feature if it implements presentation semantic
-support for all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
-attribute when applied to a content element that generates a
-block area.</p></div><div class="div3">
-<h4><a id="feature-display-inline"></a>E.1.19 #display-inline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#display-inline</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
-attribute when applied to a content element that would generate an
-inline area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#display-inline</code> feature if it implements presentation semantic
-support for all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
-attribute when applied to a content element that generates an
-inline area.</p></div><div class="div3">
-<h4><a id="feature-display-region"></a>E.1.20 #display-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#display-region</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
-attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#display-region</code> feature if it implements presentation semantic
-support for all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
-attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p></div><div class="div3">
-<h4><a id="feature-displayAlign"></a>E.1.21 #displayAlign</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#displayAlign</code> feature if it recognizes and is capable of
-transforming all defined values of the <a href="#style-attribute-displayAlign"><code>tts:displayAlign</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#displayAlign</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-displayAlign"><code>tts:displayAlign</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-dropMode"></a>E.1.22 #dropMode</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#dropMode</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#dropMode</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-dropMode-dropNTSC"></a>E.1.23 #dropMode-dropNTSC</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#dropMode-dropNTSC</code> feature if it recognizes and is capable of
-transforming the <code>dropNTSC</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#dropMode-dropNTSC</code> feature if it implements presentation semantic support
-for the <code>dropNTSC</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-dropMode-dropPAL"></a>E.1.24 #dropMode-dropPAL</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#dropMode-dropPAL</code> feature if it recognizes and is capable of
-transforming the <code>dropPAL</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#dropMode-dropPAL</code> feature if it implements presentation semantic support
-for the <code>dropPAL</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-dropMode-nonDrop"></a>E.1.25 #dropMode-nonDrop</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#dropMode-nonDrop</code> feature if it recognizes and is capable of
-transforming the <code>nonDrop</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#dropMode-nonDrop</code> feature if it implements presentation semantic support
-for the <code>nonDrop</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-extent"></a>E.1.26 #extent</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#extent</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-extent"><code>tts:extent</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#extent</code> feature if it implements presentation semantic support for
-the <a href="#style-attribute-extent"><code>tts:extent</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-extent-region"></a>E.1.27 #extent-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#extent-region</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-extent"><code>tts:extent</code></a>
-attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#extent-region</code> feature if it implements presentation semantic support for
-the <a href="#style-attribute-extent"><code>tts:extent</code></a>
-attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p></div><div class="div3">
-<h4><a id="feature-extent-root"></a>E.1.28 #extent-root</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#extent-root</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-extent"><code>tts:extent</code></a>
-attribute when applied to the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#extent-root</code> feature if it implements presentation semantic support for
-the <a href="#style-attribute-extent"><code>tts:extent</code></a>
-attribute when applied to a <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element.</p></div><div class="div3">
-<h4><a id="feature-fontFamily"></a>E.1.29 #fontFamily</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontFamily</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontFamily</code> feature if it implements presentation semantic support
-for the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-fontFamily-generic"></a>E.1.30 #fontFamily-generic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontFamily-generic</code> feature if it recognizes and is
-capable of transforming <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a>
-values when used with the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontFamily-generic</code> feature if it implements presentation semantic
-support for <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a>
-values when used with the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-fontFamily-non-generic"></a>E.1.31 #fontFamily-non-generic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontFamily-non-generic</code> feature if it recognizes and is
-capable of transforming <a href="#style-value-familyName">&lt;familyName&gt;</a>
-values when used with the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontFamily-non-generic</code> feature if it implements presentation semantic
-support for <a href="#style-value-familyName">&lt;familyName&gt;</a>
-values when used with the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-fontSize"></a>E.1.32 #fontSize</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontSize</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontSize</code> feature if it implements presentation semantic support
-for the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-fontSize-anamorphic"></a>E.1.33 #fontSize-anamorphic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontSize-anamorphic</code> feature if it recognizes and is
-capable of transforming values of the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
-attribute that consist of two <a href="#style-value-length">&lt;length&gt;</a> specifications.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontSize-anamorphic</code> feature if it implements presentation semantic
-support for defined values of the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
-attribute that consist of two <a href="#style-value-length">&lt;length&gt;</a> specifications.</p></div><div class="div3">
-<h4><a id="feature-fontSize-isomorphic"></a>E.1.34 #fontSize-isomorphic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontSize-isomorphic</code> feature if it recognizes and is
-capable of transforming values of the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
-attribute that consist of a single <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontSize-isomorphic</code> feature if it implements presentation semantic
-support for defined values of the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
-attribute that consist of a single <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
-<h4><a id="feature-fontStyle"></a>E.1.35 #fontStyle</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontStyle</code> feature if it recognizes and is capable of
-transforming all defined values of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontStyle</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-fontStyle-italic"></a>E.1.36 #fontStyle-italic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontStyle-italic</code> feature if it recognizes and is
-capable of transforming the <code>italic</code> value of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontStyle-italic</code> feature if it implements presentation semantic
-support for the <code>italic</code> of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-fontStyle-oblique"></a>E.1.37 #fontStyle-oblique</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontStyle-oblique</code> feature if it recognizes and is
-capable of transforming the <code>oblique</code> value of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontStyle-oblique</code> feature if it implements presentation semantic
-support for the <code>oblique</code> of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-fontWeight"></a>E.1.38 #fontWeight</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontWeight</code> feature if it recognizes and is capable of
-transforming all defined values of the <a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontWeight</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-fontWeight-bold"></a>E.1.39 #fontWeight-bold</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#fontWeight-bold</code> feature if it recognizes and is
-capable of transforming <code>bold</code> value of the <a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#fontWeight-bold</code> feature if it implements presentation semantic
-support for the <code>bold</code> of the <a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-frameRate"></a>E.1.40 #frameRate</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#frameRate</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-frameRate"><code>ttp:frameRate</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#frameRate</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-frameRate"><code>ttp:frameRate</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-frameRateMultiplier"></a>E.1.41 #frameRateMultiplier</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#frameRateMultiplier</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-frameRateMultiplier"><code>ttp:frameRateMultiplier</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#frameRateMultiplier</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-frameRateMultiplier"><code>ttp:frameRateMultiplier</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-layout"></a>E.1.42 #layout</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#layout</code>
-feature if it (1) recognizes and is capable of transforming the following
-vocabulary defined by <a href="#layout"><b>11 Layout</b></a>:</p><ul><li><p><a href="#layout-vocabulary-layout"><code>layout</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#layout-attribute-region">@<code>region</code></a></p></li></ul><p>and (2) supports the following attributes when applied to the
-<a href="#layout-vocabulary-region"><code>region</code></a> element:</p><ul><li><p><a href="#style-attribute-extent"><code>tts:extent</code></a></p></li><li><p><a href="#style-attribute-origin"><code>tts:origin</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#layout</code>
-feature if it implements presentation semantic support for the
-same vocabulary and features enumerated above.</p></div><div class="div3">
-<h4><a id="feature-length"></a>E.1.43 #length</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#length</code>
-feature if it recognizes and is capable of transforming all defined
-values of the <a href="#style-value-length">&lt;length&gt;</a>
-style value expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#length</code>
-feature if it implements presentation semantic support for all defined values of
-the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length</code> is intended to imply support for the following features:
-<code>#length-integer</code>,
-<code>#length-real</code>,
-<code>#length-positive</code>,
-<code>#length-negative</code>,
-<code>#length-cell</code>,
-<code>#length-em</code>,
-<code>#length-percentage</code>, and
-<code>#length-pixel</code>.</p></div></div><div class="div3">
-<h4><a id="feature-length-cell"></a>E.1.44 #length-cell</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#length-cell</code> feature if it recognizes and is capable of
-transforming scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
-that use <code>c</code> (cell) units.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#length-cell</code> feature if it implements presentation semantic support
-for scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
-that use <code>c</code> (cell) units.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-cell</code> does not, by itself, imply support for
-<code>#length-integer</code>,
-<code>#length-real</code>,
-<code>#length-positive</code>, or
-<code>#length-negative</code> features.</p></div></div><div class="div3">
-<h4><a id="feature-length-em"></a>E.1.45 #length-em</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#length-em</code> feature if it recognizes and is capable of
-transforming scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
-that use <code>em</code> (EM) units.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#length-em</code> feature if it implements presentation semantic support
-for scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
-that use <code>em</code> (EM) units.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-em</code> does not, by itself, imply support for
-<code>#length-integer</code>,
-<code>#length-real</code>,
-<code>#length-positive</code>, or
-<code>#length-negative</code> features.</p></div></div><div class="div3">
-<h4><a id="feature-length-integer"></a>E.1.46 #length-integer</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#length-integer</code> feature if it recognizes and is
-capable of transforming integer values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#length-integer</code> feature if it implements presentation semantic
-support for integer values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.
-</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-integer</code> does not, by itself, imply support for
-<code>#length-positive</code> or
-<code>#length-negative</code> features.</p></div></div><div class="div3">
-<h4><a id="feature-length-negative"></a>E.1.47 #length-negative</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#length-negative</code> feature if it recognizes and is
-capable of transforming negative values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#length-negative</code> feature if it implements presentation semantic
-support for negative values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.
-</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-negative</code> does not, by itself, imply support for
-<code>#length-integer</code> or
-<code>#length-real</code> features.</p></div></div><div class="div3">
-<h4><a id="feature-length-percentage"></a>E.1.48 #length-percentage</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#length-percentage</code> feature if it recognizes and is
-capable of transforming percentage values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#length-percentage</code> feature if it implements presentation semantic
-support for percentage values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.
-</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-percentage</code> does not, by itself, imply support for
-<code>#length-integer</code>,
-<code>#length-real</code>,
-<code>#length-positive</code>, or
-<code>#length-negative</code> features.</p></div></div><div class="div3">
-<h4><a id="feature-length-pixel"></a>E.1.49 #length-pixel</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#length-pixel</code> feature if it recognizes and is capable of
-transforming scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
-that use <code>px</code> (pixel) units.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#length-pixel</code> feature if it implements presentation semantic support
-for scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
-that use <code>px</code> (pixel) units.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-pixel</code> does not, by itself, imply support for
-<code>#length-integer</code>,
-<code>#length-real</code>,
-<code>#length-positive</code>, or
-<code>#length-negative</code> features.</p></div></div><div class="div3">
-<h4><a id="feature-length-positive"></a>E.1.50 #length-positive</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#length-positive</code> feature if it recognizes and is
-capable of transforming positive values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#length-positive</code> feature if it implements presentation semantic
-support for positive values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.
-</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-positive</code> is intended to imply support for zero valued
-<a href="#style-value-length">&lt;length&gt;</a> style value
-expressions.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-positive</code> does not, by itself, imply support for
-<code>#length-integer</code> or
-<code>#length-real</code> features.</p></div></div><div class="div3">
-<h4><a id="feature-length-real"></a>E.1.51 #length-real</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#length-real</code> feature if it recognizes and is
-capable of transforming real values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#length-real</code> feature if it implements presentation semantic
-support for real values of the <a href="#style-value-length">&lt;length&gt;</a> style value
-expression.
-</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-real</code> is intended to imply support for
-integer valued <a href="#style-value-length">&lt;length&gt;</a> style value
-expressions as well as real valued expressions.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-real</code> does not, by itself, imply support for
-<code>#length-positive</code> or
-<code>#length-negative</code> features.</p></div></div><div class="div3">
-<h4><a id="feature-lineBreak-uax14"></a>E.1.52 #lineBreak-uax14</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#lineBreak-uax14</code> feature if it recognizes and is capable of
-transforming requirements expressed by <a href="#uax14">[UAX14]</a> into its
-target document space.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#lineBreak-uax14</code> feature if it implements presentation semantic support
-for <a href="#uax14">[UAX14]</a> as applies to line breaking.</p></div><div class="div3">
-<h4><a id="feature-lineHeight"></a>E.1.53 #lineHeight</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#lineHeight</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-lineHeight"><code>tts:lineHeight</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#lineHeight</code> feature if it implements presentation semantic support for
-the <a href="#style-attribute-lineHeight"><code>tts:lineHeight</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-markerMode"></a>E.1.54 #markerMode</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#markerMode</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#markerMode</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-markerMode-continuous"></a>E.1.55 #markerMode-continuous</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#markerMode-continuous</code> feature if it recognizes and is capable of
-transforming the <code>continuous</code> value of the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#markerMode-continuous</code> feature if it implements presentation semantic support
-for the <code>continuous</code> value of the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-markerMode-discontinuous"></a>E.1.56 #markerMode-discontinuous</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#markerMode-discontinuous</code> feature if it recognizes and is capable of
-transforming the <code>discontinuous</code> value of the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#markerMode-discontinuous</code> feature if it implements presentation semantic support
-for the <code>discontinuous</code> value of the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-metadata"></a>E.1.57 #metadata</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#metadata</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <a href="#metadata"><b>14 Metadata</b></a>:</p><ul><li><p><a href="#metadata-vocabulary-metadata"><code>metadata</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:title</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:desc</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:copyright</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:agent</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:name</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:actor</code></a></p></li><li><p><a href="#metadata-attribute-agent">@<code>ttm:agent</code></a></p></li><li><p><a href="#metadata-attribute-role">@<code>ttm:role</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#metadata</code>
-feature if it recognizes and is capable of presenting the information
-expressed by the same vocabulary enumerated above.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not define a standardized form for the
-presentation of metadata information. The presentation or ability to
-present metadata information is considered to be implementation
-dependent.</p></div></div><div class="div3">
-<h4><a id="feature-nested-div"></a>E.1.58 #nested-div</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#nested-div</code>
-feature if it recognizes and is capable of transforming nested
-<a href="#content-vocabulary-div"><code>div</code></a> elements.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#nested-div</code>
-feature if it implements presentation semantic support for nested
-<a href="#content-vocabulary-div"><code>div</code></a> elements.</p></div><div class="div3">
-<h4><a id="feature-nested-span"></a>E.1.59 #nested-span</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#nested-span</code>
-feature if it recognizes and is capable of transforming nested
-<a href="#content-vocabulary-span"><code>span</code></a> elements.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#nested-span</code>
-feature if it implements presentation semantic support for nested
-<a href="#content-vocabulary-span"><code>span</code></a> elements.</p></div><div class="div3">
-<h4><a id="feature-opacity"></a>E.1.60 #opacity</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#opacity</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-opacity"><code>tts:opacity</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#opacity</code> feature if it (1) implements presentation semantic support for
-the <a href="#style-attribute-opacity"><code>tts:opacity</code></a>
-attribute and (2) is capable of displaying or generating an output display
-signal that distinguishes between at least eight (8) values of opacity.</p></div><div class="div3">
-<h4><a id="feature-origin"></a>E.1.61 #origin</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#origin</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-origin"><code>tts:origin</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#origin</code> feature if it implements presentation semantic support for
-the <a href="#style-attribute-origin"><code>tts:origin</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-overflow"></a>E.1.62 #overflow</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#overflow</code> feature if it recognizes and is capable of
-transforming all defined values of the <a href="#style-attribute-overflow"><code>tts:overflow</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#overflow</code> feature if it implements presentation semantic support for
-all defined values of the <a href="#style-attribute-overflow"><code>tts:overflow</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-overflow-visible"></a>E.1.63 #overflow-visible</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#overflow-visible</code> feature if it recognizes and is capable of
-transforming the <code>visible</code> value of the <a href="#style-attribute-overflow"><code>tts:overflow</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#overflow-visible</code> feature if it implements presentation semantic support for
-the <code>visible</code> value of the <a href="#style-attribute-overflow"><code>tts:overflow</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-padding"></a>E.1.64 #padding</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#padding</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-padding"><code>tts:padding</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#padding</code> feature if it implements presentation semantic support for
-the <a href="#style-attribute-padding"><code>tts:padding</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-padding-1"></a>E.1.65 #padding-1</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#padding-1</code> feature if it recognizes and is capable of
-transforming values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
-that consist of one <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#padding-1</code>
-feature if it implements presentation semantic support for values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
-that consist of one <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
-<h4><a id="feature-padding-2"></a>E.1.66 #padding-2</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#padding-2</code> feature if it recognizes and is capable of
-transforming values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
-that consist of two <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#padding-2</code>
-feature if it implements presentation semantic support for values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
-that consist of two <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
-<h4><a id="feature-padding-3"></a>E.1.67 #padding-3</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#padding-3</code> feature if it recognizes and is capable of
-transforming values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
-that consist of three <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#padding-3</code>
-feature if it implements presentation semantic support for values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
-that consist of three <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
-<h4><a id="feature-padding-4"></a>E.1.68 #padding-4</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#padding-4</code> feature if it recognizes and is capable of
-transforming values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
-that consist of four <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#padding-4</code>
-feature if it implements presentation semantic support for values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
-that consist of four <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
-<h4><a id="feature-pixelAspectRatio"></a>E.1.69 #pixelAspectRatio</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#pixelAspectRatio</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-pixelAspectRatio"><code>ttp:pixelAspectRatio</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#pixelAspectRatio</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-pixelAspectRatio"><code>ttp:pixelAspectRatio</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-presentation"></a>E.1.70 #presentation</h4><p>A TTML processor supports the
-<code>#presentation</code> feature if it
-(1) satisfies the generic processor criteria defined by 
-<a href="#conformance-generic-processor"><b>3.2.1 Generic Processor Conformance</b></a>,
-(2) implements support for the region and line layout
-semantics defined by <a href="#semantics-region-layout"><b>11.3.1 Region Layout and Presentation</b></a> and
-<a href="#semantics-line-layout"><b>11.3.2 Line Layout</b></a>, respectively, and
-(3) implements presentation semantics for the following features:</p><ul><li><p><a href="#content"><code>#content</code></a></p></li><li><p><a href="#feature-core"><code>#core</code></a></p></li><li><p><a href="#feature-profile"><code>#profile</code></a></p></li><li><p><a href="#feature-structure"><code>#structure</code></a></p></li><li><p><a href="#feature-time-offset"><code>#time-offset</code></a></p></li><li><p><a href="#timing"><code>#timing</code></a></p></li></ul><p>
-In addition, a TTML processor that supports the
-<code>#presentation</code> feature should satisfy the user agent
-accessibility guidelines specified by <a href="#uaag">[UAAG]</a>.</p></div><div class="div3">
-<h4><a id="feature-profile"></a>E.1.71 #profile</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#profile</code>
-feature if it recognizes and is capable of transforming the
-<a href="#profile-attribute-profile"><code>ttp:profile</code></a>
-attribute on the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element and
-transforming the following vocabulary defined by
-<a href="#parameter-element-vocabulary"><b>7.1 Parameter Element Vocabulary</b></a>:</p><ul><li><p><a href="#profile-vocabulary-profile"><code>ttp:profile</code></a></p></li><li><p><a href="#profile-vocabulary-features"><code>ttp:features</code></a></p></li><li><p><a href="#profile-vocabulary-feature"><code>ttp:feature</code></a></p></li><li><p><a href="#profile-vocabulary-extensions"><code>ttp:extensions</code></a></p></li><li><p><a href="#profile-vocabulary-extension"><code>ttp:extension</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#profile</code> feature if it implements presentation semantic support
-for the same vocabulary specified above.</p></div><div class="div3">
-<h4><a id="feature-showBackground"></a>E.1.72 #showBackground</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#showBackground</code> feature if it recognizes and is capable
-of transforming all defined values of the <a href="#style-attribute-showBackground"><code>tts:showBackground</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#showBackground</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-showBackground"><code>tts:showBackground</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-structure"></a>E.1.73 #structure</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#structure</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <a href="#content"><b>8 Content</b></a>:</p><ul><li><p><a href="#document-structure-vocabulary-tt"><code>tt</code></a></p></li><li><p><a href="#document-structure-vocabulary-head"><code>head</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#structure</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p></div><div class="div3">
-<h4><a id="feature-styling"></a>E.1.74 #styling</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#styling</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <a href="#styling"><b>10 Styling</b></a>:</p><ul><li><p><a href="#styling-vocabulary-styling"><code>styling</code></a></p></li><li><p><a href="#styling-vocabulary-style"><code>style</code></a></p></li><li><p><a href="#style-attribute-style">@<code>style</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#styling</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p></div><div class="div3">
-<h4><a id="feature-styling-chained"></a>E.1.75 #styling-chained</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#styling-chained</code> feature if it recognizes and is capable
-of transforming chained style association as defined by <a href="#semantics-style-association-chained-referential"><b>10.4.1.3 Chained Referential Styling</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#styling-chained</code> feature if it implements presentation semantic
-support for chained style association as defined by <a href="#semantics-style-association-chained-referential"><b>10.4.1.3 Chained Referential Styling</b></a>.</p></div><div class="div3">
-<h4><a id="feature-styling-inheritance-content"></a>E.1.76 #styling-inheritance-content</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#styling-inheritance</code> feature if it recognizes and is
-capable of transforming content style inheritance as defined by
-<a href="#semantics-style-inheritance-content"><b>10.4.2.1 Content Style Inheritance</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#styling-inheritance-content</code> feature if it implements
-presentation semantic support for content style inheritance as defined by <a href="#semantics-style-inheritance-content"><b>10.4.2.1 Content Style Inheritance</b></a>.</p></div><div class="div3">
-<h4><a id="feature-styling-inheritance-region"></a>E.1.77 #styling-inheritance-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#styling-inheritance</code> feature if it recognizes and is
-capable of transforming region style inheritance as defined by
-<a href="#semantics-style-inheritance-region"><b>10.4.2.2 Region Style Inheritance</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#styling-inheritance-region</code> feature if it implements
-presentation semantic support for region style inheritance as defined by <a href="#semantics-style-inheritance-region"><b>10.4.2.2 Region Style Inheritance</b></a>.</p></div><div class="div3">
-<h4><a id="feature-styling-inline"></a>E.1.78 #styling-inline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#styling-inline</code> feature if it recognizes and is capable
-of transforming inline style association as defined by <a href="#semantics-style-association-inline"><b>10.4.1.1 Inline Styling</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#styling-inline</code> feature if it implements presentation semantic support
-for inline style association as defined by <a href="#semantics-style-association-inline"><b>10.4.1.1 Inline Styling</b></a>.</p></div><div class="div3">
-<h4><a id="feature-styling-nested"></a>E.1.79 #styling-nested</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#styling-nested</code> feature if it recognizes and is capable
-of transforming nested style association as defined by <a href="#semantics-style-association-nested"><b>10.4.1.4 Nested Styling</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#styling-nested</code> feature if it implements presentation semantic support
-for nested style association as defined by <a href="#semantics-style-association-nested"><b>10.4.1.4 Nested Styling</b></a>.</p></div><div class="div3">
-<h4><a id="feature-styling-referential"></a>E.1.80 #styling-referential</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#styling-referential</code> feature if it recognizes and is capable
-of transforming referential style association as defined by <a href="#semantics-style-association-referential"><b>10.4.1.2 Referential Styling</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#styling-referential</code> feature if it implements presentation semantic
-support for referential style association as defined by <a href="#semantics-style-association-referential"><b>10.4.1.2 Referential Styling</b></a>.</p></div><div class="div3">
-<h4><a id="feature-subFrameRate"></a>E.1.81 #subFrameRate</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#subFrameRate</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-subFrameRate"><code>ttp:subFrameRate</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#subFrameRate</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-subFrameRate"><code>ttp:subFrameRate</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textAlign"></a>E.1.82 #textAlign</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textAlign</code> feature if it recognizes and is capable
-of transforming all defined values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textAlign</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textAlign-absolute"></a>E.1.83 #textAlign-absolute</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textAlign-absolute</code> feature if it recognizes and is
-capable of transforming the <code>left</code>, <code>center</code>,
-and <code>right</code> values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textAlign-absolute</code> feature if it implements presentation semantic
-support for the <code>left</code>, <code>center</code>, and
-<code>right</code> values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textAlign-relative"></a>E.1.84 #textAlign-relative</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textAlign-relative</code> feature if it recognizes and is
-capable of transforming the <code>start</code>, <code>center</code>,
-and <code>end</code> values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textAlign-relative</code> feature if it implements presentation semantic
-support for the <code>start</code>, <code>center</code>, and
-<code>end</code> values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textDecoration"></a>E.1.85 #textDecoration</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textDecoration</code> feature if it recognizes and is capable
-of transforming all defined values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textDecoration</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textDecoration-over"></a>E.1.86 #textDecoration-over</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textDecoration-over</code> feature if it recognizes and is
-capable of transforming the <code>overline</code> and
-<code>noOverline</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textDecoration-over</code> feature if it implements
-presentation semantic support for the <code>overline</code> and
-<code>noOverline</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textDecoration-through"></a>E.1.87 #textDecoration-through</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textDecoration-through</code> feature if it recognizes and is
-capable of transforming the <code>lineThrough</code> and
-<code>noLineThrough</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textDecoration-through</code> feature if it implements
-presentation semantic support for the <code>lineThrough</code> and
-<code>noLineThrough</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textDecoration-under"></a>E.1.88 #textDecoration-under</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textDecoration-under</code> feature if it recognizes and is
-capable of transforming the <code>underline</code> and
-<code>noUnderline</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textDecoration-under</code> feature if it implements
-presentation semantic support for the <code>underline</code> and
-<code>noUnderline</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textOrientation"></a>E.1.89 #textOrientation</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textOrientation</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-textOrientation"><code>tts:textOrientation</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textOrientation</code> feature if it implements presentation semantic support
-for the <a href="#style-attribute-textOrientation"><code>tts:textOrientation</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textOutline"></a>E.1.90 #textOutline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textOutline</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textOutline</code> feature if it implements presentation semantic support
-for the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-textOutline-blurred"></a>E.1.91 #textOutline-blurred</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textOutline-blurred</code> feature if it recognizes and is capable of
-transforming values of the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
-attribute that includes a blur radius specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textOutline-blurred</code> feature if it implements presentation semantic support
-for values of the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
-attribute that includes a blur radius specification.</p></div><div class="div3">
-<h4><a id="feature-textOutline-unblurred"></a>E.1.92 #textOutline-unblurred</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#textOutline-unblurred</code> feature if it recognizes and is capable of
-transforming values of the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
-attribute that does not include a blur radius specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#textOutline-unblurred</code> feature if it implements presentation semantic support
-for values of the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
-attribute that does not include a blur radius specification.</p></div><div class="div3">
-<h4><a id="feature-tickRate"></a>E.1.93 #tickRate</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#tickRate</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-tickRate"><code>ttp:tickRate</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#tickRate</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-tickRate"><code>ttp:tickRate</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-timeBase-clock"></a>E.1.94 #timeBase-clock</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#timeBase-clock</code> feature if it recognizes and is capable
-of transforming the <code>clock</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
-attribute and if it supports the <a href="#feature-clockMode"><code>#clockMode</code></a> feature.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#timeBase-clock</code> feature if it implements presentation
-semantic support for the <code>clock</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
-attribute and if it supports the <a href="#feature-clockMode"><code>#clockMode</code></a> feature.</p></div><div class="div3">
-<h4><a id="feature-timeBase-media"></a>E.1.95 #timeBase-media</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#timeBase-media</code> feature if it recognizes and is capable
-of transforming the <code>media</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#timeBase-media</code> feature if it implements presentation
-semantic support for the <code>media</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-timeBase-smpte"></a>E.1.96 #timeBase-smpte</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#timeBase-smpte</code> feature if it recognizes and is capable
-of transforming the <code>smpte</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
-attribute and if it supports the <a href="#feature-dropMode"><code>#dropMode</code></a> feature.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#timeBase-smpte</code> feature if it implements presentation
-semantic support for the <code>smpte</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
-attribute and if it supports the <a href="#feature-dropMode"><code>#dropMode</code></a> feature.</p></div><div class="div3">
-<h4><a id="feature-timeContainer"></a>E.1.97 #timeContainer</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#timeContainer</code> feature if it recognizes and is capable of
-transforming the <a href="#timing-attribute-timeContainer"><code>timeContainer</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#timeContainer</code> feature if it implements presentation semantic support
-for the <a href="#timing-attribute-timeContainer"><code>timeContainer</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-time-clock"></a>E.1.98 #time-clock</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#time-clock</code> feature if it recognizes and is capable of
-transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
-satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
-&lt;timeExpression&gt;
-  : hours ":" minutes ":" seconds ( fraction )?
-</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#time-clock</code> feature if it implements presentation
-semantic support for the same syntax specified above.</p></div><div class="div3">
-<h4><a id="feature-time-clock-with-frames"></a>E.1.99 #time-clock-with-frames</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#time-clock-with-frames</code> feature if it supports the
-<a href="#feature-frameRate"><code>#frameRate</code></a>,
-<a href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></a>, and
-<a href="#feature-subFrameRate"><code>#subFrameRate</code></a> features
-and if it recognizes and is capable of
-transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
-satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
-&lt;timeExpression&gt;
-  : hours ":" minutes ":" seconds ( fraction | ":" frames ( "." sub-frames )? )?
-</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#time-clock-with-frames</code> feature if it implements
-presentation semantic support for the same features and syntax
-specified above.</p></div><div class="div3">
-<h4><a id="feature-time-offset"></a>E.1.100 #time-offset</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#time-offset</code> feature if it recognizes and is capable of
-transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
-satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
-&lt;timeExpression&gt;
-  : time-count fraction? ( "h" | "m" | "s" | "ms" )
-</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#time-offset</code> feature if it implements presentation
-semantic support for the same syntax specified above.</p></div><div class="div3">
-<h4><a id="feature-time-offset-with-frames"></a>E.1.101 #time-offset-with-frames</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#time-offset-with-frames</code> feature if it supports the
-<a href="#feature-frameRate"><code>#frameRate</code></a>,
-<a href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></a>, and
-<a href="#feature-subFrameRate"><code>#subFrameRate</code></a> features
-and if it recognizes and is capable of
-transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
-satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
-&lt;timeExpression&gt;
-  : time-count fraction? "f"
-</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#time-offset-with-frames</code> feature if it implements
-presentation semantic support for the same features and syntax
-specified above.</p></div><div class="div3">
-<h4><a id="feature-time-offset-with-ticks"></a>E.1.102 #time-offset-with-ticks</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#time-offset-with-ticks</code> feature if it supports the 
-<a href="#feature-tickRate"><code>#tickRate</code></a> feature
-and if it recognizes and is capable of
-transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
-satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
-&lt;timeExpression&gt;
-  : time-count fraction? "t"
-</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#time-offset-with-ticks</code> feature if it implements presentation
-semantic support for the same features and syntax specified above.</p></div><div class="div3">
-<h4><a id="feature-timing"></a>E.1.103 #timing</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#timing</code>
-feature if it recognizes and is capable of transforming the following
-vocabulary defined by <a href="#timing"><b>12 Timing</b></a>:</p><ul><li><p><a href="#timing-attribute-begin">@<code>begin</code></a></p></li><li><p><a href="#timing-attribute-dur">@<code>dur</code></a></p></li><li><p><a href="#timing-attribute-end">@<code>end</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#timing</code>
-feature if it implements presentation semantic support for the
-same vocabulary enumerated above.</p></div><div class="div3">
-<h4><a id="feature-transformation"></a>E.1.104 #transformation</h4><p>A TTML processor supports the
-<code>#transformation</code> feature if it
-(1) satisfies the generic processor criteria defined by 
-<a href="#conformance-generic-processor"><b>3.2.1 Generic Processor Conformance</b></a> and
-(2) implements the transformation semantics of the following features:</p><ul><li><p><a href="#content"><code>#content</code></a></p></li><li><p><a href="#feature-core"><code>#core</code></a></p></li><li><p><a href="#feature-profile"><code>#profile</code></a></p></li><li><p><a href="#feature-structure"><code>#structure</code></a></p></li><li><p><a href="#feature-time-offset"><code>#time-offset</code></a></p></li><li><p><a href="#timing"><code>#timing</code></a></p></li></ul></div><div class="div3">
-<h4><a id="feature-unicodeBidi"></a>E.1.105 #unicodeBidi</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#unicodeBidi</code> feature if it recognizes and is capable of
-transforming all defined values of the <a href="#style-attribute-unicodeBidi"><code>tts:unicodeBidi</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#unicodeBidi</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-unicodeBidi"><code>tts:unicodeBidi</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-version"></a>E.1.106 #version</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#version</code> feature if it recognizes and is capable of
-transforming the <a href="#parameter-attribute-version"><code>ttp:version</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#version</code> feature if it implements presentation semantic support
-for the <a href="#parameter-attribute-version"><code>ttp:version</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-visibility"></a>E.1.107 #visibility</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#visibility</code> feature if it recognizes and is capable
-of transforming all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#visibility</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-visibility-block"></a>E.1.108 #visibility-block</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#visibility-block</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
-attribute when applied to a content element that would generate a
-block area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#visibility-block</code> feature if it implements presentation semantic
-support for all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
-attribute when applied to a content element that generates a
-block area.</p></div><div class="div3">
-<h4><a id="feature-visibility-inline"></a>E.1.109 #visibility-inline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#visibility-inline</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
-attribute when applied to a content element that would generate an
-inline area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#visibility-inline</code> feature if it implements presentation semantic
-support for all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
-attribute when applied to a content element that generates an
-inline area.</p></div><div class="div3">
-<h4><a id="feature-visibility-region"></a>E.1.110 #visibility-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#visibility-region</code> feature if it recognizes and is
-capable of transforming all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
-attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#visibility-region</code> feature if it implements presentation semantic
-support for all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
-attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p></div><div class="div3">
-<h4><a id="feature-wrapOption"></a>E.1.111 #wrapOption</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#wrapOption</code> feature if it recognizes and is capable
-of transforming all defined values of the <a href="#style-attribute-wrapOption"><code>tts:wrapOption</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#wrapOption</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-wrapOption"><code>tts:wrapOption</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-writingMode"></a>E.1.112 #writingMode</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#writingMode</code> feature if it recognizes and is capable
-of transforming all defined values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#writingMode</code> feature if it implements presentation semantic support
-for all defined values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-writingMode-vertical"></a>E.1.113 #writingMode-vertical</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#writingMode-vertical</code> feature if it recognizes and is
-capable of transforming the <code>tbrl</code>, <code>tblr</code>, and
-<code>tb</code> values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#writingMode-vertical</code> feature if it implements presentation semantic
-support for the <code>tbrl</code>, <code>tblr</code>, and
-<code>tb</code> values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-writingMode-horizontal"></a>E.1.114 #writingMode-horizontal</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#writingMode-horizontal</code> feature if it recognizes and is
-capable of transforming the <code>lrtb</code>, <code>rltb</code>,
-<code>lr</code> and <code>rl</code> values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#writingMode-horizontal</code> feature if it implements presentation semantic
-support for the <code>lrtb</code>, <code>rltb</code>, <code>lr</code>
-and <code>rl</code> values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-writingMode-horizontal-lr"></a>E.1.115 #writingMode-horizontal-lr</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#writingMode-horizontal</code> feature if it recognizes and is
-capable of transforming the <code>lrtb</code> and <code>lr</code>
-values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#writingMode-horizontal-lr</code> feature if it implements presentation semantic
-support for the <code>lrtb</code> and <code>lr</code> values of the
-<a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-writingMode-horizontal-rl"></a>E.1.116 #writingMode-horizontal-rl</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#writingMode-horizontal</code> feature if it recognizes and is
-capable of transforming the <code>rltb</code> and <code>rl</code>
-values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#writingMode-horizontal-rl</code> feature if it implements presentation semantic
-support for the <code>rltb</code> and <code>rl</code> values of the
-<a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
-attribute.</p></div><div class="div3">
-<h4><a id="feature-zIndex"></a>E.1.117 #zIndex</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
-<code>#zIndex</code> feature if it recognizes and is capable of
-transforming the <a href="#style-attribute-zIndex"><code>tts:zIndex</code></a>
-attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
-<code>#zIndex</code> feature if it implements presentation semantic support for
-the <a href="#style-attribute-zIndex"><code>tts:zIndex</code></a>
-attribute.</p></div></div><div class="div2">
-<h3><a id="feature-support"></a>E.2 Feature Support</h3><p>The following table, <a href="#feature-support-table"><b>Table E-1 – Feature Support</b></a>,
-enumerates every defined feature designation (expressed without the TT
-Feature Namespace), and, for each designated feature, specifies
-whether the feature must be implemented, i.e., is mandatory (M), or may be implemented, i.e.,
-is optional (O), for transformation and <a href="#terms-presentation-processor">presentation processor</a>s.</p><a id="feature-support-table"></a><table class="common"><caption>Table E-1 – Feature Support</caption><col width="60%" span="1"><col width="20%" span="1"><col width="20%" span="1"><tbody><tr><td><span class="strong">Feature</span></td><td><span class="strong">Transformation</span></td><td><span class="strong">Presentation</span></td></tr><tr><td><a href="#feature-animation"><code>#animation</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-backgroundColor"><code>#backgroundColor</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-backgroundColor-block"><code>#backgroundColor-block</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-backgroundColor-inline"><code>#backgroundColor-inline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-backgroundColor-region"><code>#backgroundColor-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-bidi"><code>#bidi</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-border"><code>#border</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-cellResolution"><code>#cellResolution</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-clockMode"><code>#clockMode</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-clockMode-gps"><code>#clockMode-gps</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-clockMode-local"><code>#clockMode-local</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-clockMode-utc"><code>#clockMode-utc</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-color"><code>#color</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-content"><code>#content</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-core"><code>#core</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-direction"><code>#direction</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-display"><code>#display</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-display-block"><code>#display-block</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-display-inline"><code>#display-inline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-display-region"><code>#display-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-displayAlign"><code>#displayAlign</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-dropMode"><code>#dropMode</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-dropMode-dropNTSC"><code>#dropMode-dropNTSC</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-dropMode-dropPAL"><code>#dropMode-dropPAL</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-dropMode-nonDrop"><code>#dropMode-nonDrop</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-extent"><code>#extent</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-extent-region"><code>#extent-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-extent-root"><code>#extent-root</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontFamily"><code>#fontFamily</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontFamily-generic"><code>#fontFamily-generic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontFamily-non-generic"><code>#fontFamily-non-generic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontSize"><code>#fontSize</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontSize-anamorphic"><code>#fontSize-anamorphic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontSize-isomorphic"><code>#fontSize-isomorphic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontStyle"><code>#fontStyle</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontStyle-italic"><code>#fontStyle-italic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontStyle-oblique"><code>#fontStyle-oblique</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontWeight"><code>#fontWeight</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontWeight-bold"><code>#fontWeight-bold</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-frameRate"><code>#frameRate</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-layout"><code>#layout</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length"><code>#length</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-cell"><code>#length-cell</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-em"><code>#length-em</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-integer"><code>#length-integer</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-negative"><code>#length-negative</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-percentage"><code>#length-percentage</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-pixel"><code>#length-pixel</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-positive"><code>#length-positive</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-real"><code>#length-real</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-lineBreak-uax14"><code>#lineBreak-uax14</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-lineHeight"><code>#lineHeight</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-markerMode"><code>#markerMode</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-markerMode-continuous"><code>#markerMode-continuous</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-markerMode-discontinuous"><code>#markerMode-discontinuous</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-metadata"><code>#metadata</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-nested-div"><code>#nested-div</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-nested-span"><code>#nested-span</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-opacity"><code>#opacity</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-origin"><code>#origin</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-overflow"><code>#overflow</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-overflow-visible"><code>#overflow-visible</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding"><code>#padding</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding-1"><code>#padding-1</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding-2"><code>#padding-2</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding-3"><code>#padding-3</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding-4"><code>#padding-4</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-pixelAspectRatio"><code>#pixelAspectRatio</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-presentation"><code>#presentation</code></a></td><td>O</td><td>M</td></tr><tr><td><a href="#feature-profile"><code>#profile</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-showBackground"><code>#showBackground</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-structure"><code>#structure</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-styling"><code>#styling</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-chained"><code>#styling-chained</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-inheritance-content"><code>#styling-inheritance-content</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-inheritance-region"><code>#styling-inheritance-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-inline"><code>#styling-inline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-nested"><code>#styling-nested</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-referential"><code>#styling-referential</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-subFrameRate"><code>#subFrameRate</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textAlign"><code>#textAlign</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textAlign-absolute"><code>#textAlign-absolute</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textAlign-relative"><code>#textAlign-relative</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textDecoration"><code>#textDecoration</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textDecoration-over"><code>#textDecoration-over</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textDecoration-through"><code>#textDecoration-through</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textDecoration-under"><code>#textDecoration-under</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textOrientation"><code>#textOrientation</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textOutline"><code>#textOutline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textOutline-blurred"><code>#textOutline-blurred</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textOutline-unblurred"><code>#textOutline-unblurred</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-tickRate"><code>#tickRate</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timeBase-clock"><code>#timeBase-clock</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timeBase-media"><code>#timeBase-media</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timeBase-smpte"><code>#timeBase-smpte</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timeContainer"><code>#timeContainer</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-time-clock"><code>#time-clock</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-time-clock-with-frames"><code>#time-clock-with-frames</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-time-offset"><code>#time-offset</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-time-offset-with-frames"><code>#time-offset-with-frames</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-time-offset-with-ticks"><code>#time-offset-with-ticks</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timing"><code>#timing</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-transformation"><code>#transformation</code></a></td><td>M</td><td>O</td></tr><tr><td><a href="#feature-unicodeBidi"><code>#unicodeBidi</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-version"><code>#version</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-visibility"><code>#visibility</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-visibility-block"><code>#visibility-block</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-visibility-inline"><code>#visibility-inline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-visibility-region"><code>#visibility-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-wrapOption"><code>#wrapOption</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode"><code>#writingMode</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode-vertical"><code>#writingMode-vertical</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode-horizontal"><code>#writingMode-horizontal</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode-horizontal-lr"><code>#writingMode-horizontal-lr</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode-horizontal-rl"><code>#writingMode-horizontal-rl</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-zIndex"><code>#zIndex</code></a></td><td>O</td><td>O</td></tr></tbody></table><p>For the sake of convenience, the following table,
-<a href="#feature-transformation-mandatory-table"><b>Table E-2 – Mandatory Features - Transformation</b></a>, enumerates all
-mandatory features for a TTML <a href="#terms-transformation-processor">transformation processor</a>, providing additional
-comments to summarize the context of usage or the nature of the feature.
-The <a href="#terms-profile-definition-document">profile definition document</a> that defines the corresponding
-TTML Transformation Profile is specified in
-<a href="#profile-ttml2-transformation"><b>G.3 TTML2 Transformation Profile</b></a>.
-</p><a id="feature-transformation-mandatory-table"></a><table class="common"><caption>Table E-2 – Mandatory Features - Transformation</caption><col width="60%" span="1"><col width="40%" span="1"><tbody><tr><td><span class="strong">Feature</span></td><td><span class="strong">Comments</span></td></tr><tr><td><a href="#feature-content"><code>#content</code></a></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>,
-<a href="#content-vocabulary-br"><code>br</code></a>
-</td></tr><tr><td><a href="#feature-core"><code>#core</code></a></td><td>
-<a href="#content-attribute-xml-id">@<code>xml:id</code></a>,
-<a href="#content-attribute-xml-id">@<code>xml:lang</code></a>,
-<a href="#content-attribute-xml-id">@<code>xml:space</code></a>
-</td></tr><tr><td><a href="#feature-profile"><code>#profile</code></a></td><td></td></tr><tr><td><a href="#feature-structure"><code>#structure</code></a></td><td>
-<a href="#document-structure-vocabulary-tt"><code>tt</code></a>,
-<a href="#document-structure-vocabulary-head"><code>head</code></a>
-</td></tr><tr><td><a href="#feature-time-offset"><code>#time-offset</code></a></td><td></td></tr><tr><td><a href="#feature-timing"><code>#timing</code></a></td><td>
-<a href="#timing-attribute-begin">@<code>begin</code></a>,
-<a href="#timing-attribute-dur">@<code>dur</code></a>,
-<a href="#timing-attribute-end">@<code>end</code></a>
-</td></tr><tr><td><a href="#feature-transformation"><code>#transformation</code></a></td><td></td></tr></tbody></table><p>For the sake of convenience, the following table,
-<a href="#feature-presentation-mandatory-table"><b>Table E-3 – Mandatory Features - Presentation</b></a>, enumerates all
-mandatory features for a TTML <a href="#terms-presentation-processor">presentation processor</a>, providing additional
-comments to summarize the context of usage or the nature of the feature.
-The <a href="#terms-profile-definition-document">profile definition document</a> that defines the corresponding
-TTML Presentation Profile is specified in
-<a href="#profile-ttml2-presentation"><b>G.2 TTML2 Presentation Profile</b></a>.
-</p><a id="feature-presentation-mandatory-table"></a><table class="common"><caption>Table E-3 – Mandatory Features - Presentation</caption><col width="60%" span="1"><col width="40%" span="1"><tbody><tr><td><span class="strong">Feature</span></td><td><span class="strong">Comments</span></td></tr><tr><td><a href="#feature-content"><code>#content</code></a></td><td>
-<a href="#document-structure-vocabulary-body"><code>body</code></a>,
-<a href="#content-vocabulary-div"><code>div</code></a>,
-<a href="#content-vocabulary-p"><code>p</code></a>,
-<a href="#content-vocabulary-span"><code>span</code></a>,
-<a href="#content-vocabulary-br"><code>br</code></a>
-</td></tr><tr><td><a href="#feature-core"><code>#core</code></a></td><td>
-<a href="#content-attribute-xml-id">@<code>xml:id</code></a>,
-<a href="#content-attribute-xml-id">@<code>xml:lang</code></a>,
-<a href="#content-attribute-xml-id">@<code>xml:space</code></a>
-</td></tr><tr><td><a href="#feature-profile"><code>#profile</code></a></td><td></td></tr><tr><td><a href="#feature-presentation"><code>#presentation</code></a></td><td></td></tr><tr><td><a href="#feature-structure"><code>#structure</code></a></td><td>
-<a href="#document-structure-vocabulary-tt"><code>tt</code></a>,
-<a href="#document-structure-vocabulary-head"><code>head</code></a>
-</td></tr><tr><td><a href="#feature-time-offset"><code>#time-offset</code></a></td><td></td></tr><tr><td><a href="#feature-timing"><code>#timing</code></a></td><td>
-<a href="#timing-attribute-begin">@<code>begin</code></a>,
-<a href="#timing-attribute-dur">@<code>dur</code></a>,
-<a href="#timing-attribute-end">@<code>end</code></a>
-</td></tr></tbody></table></div></div><div class="div1">
-<h2><a id="extensions"></a>F Extensions</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the syntactic form of extension designations, which are
-used to express authorial intent regarding the support for extension
-mechanisms in a TTML processor.</p><div class="div2">
-<h3><a id="extension-designations"></a>F.1 Extension Designations</h3><p>An extension designation is expressed as a string that adheres to the following
-form:</p><div class="exampleInner"><pre>
-extension-designation
-  : extension-namespace designation
-
-extension-namespace
-  : <em>TT Extension Namespace</em>                  // http://www.w3.org/ns/ttml/extension/
-  | <em>Other Extension Namespace</em>               // expressed as an absolute URI
-
-designation
-  : "#" token-char+
-
-token-char
-  : { XML NameChar }                        // XML 1.1 Production [4a]
-</pre></div><p>If the extension namespace of an extension designation is the TT
-Extension Namespace, then all values of the following
-<code>designation</code> token are reserved for future
-standardization.</p><p>If the extension namespace of an extension designation is not the
-TT Extension Namespace, i.e., is an <em>Other Extension Namespace</em>,
-then the extension namespace must be expressed as an absolute URI
-capable of serving as a base URI used in combination with a
-<code>designation</code> token that takes the form of a fragment
-identifier.</p></div></div><div class="div1">
-<h2><a id="standard-profiles"></a>G Standard Profiles</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the following standard TTML profiles:</p><ul><li><p><a href="#profile-ttml2-full"><b>G.1 TTML2 Full Profile</b></a></p></li><li><p><a href="#profile-ttml2-presentation"><b>G.2 TTML2 Presentation Profile</b></a></p></li><li><p><a href="#profile-ttml2-transformation"><b>G.3 TTML2 Transformation Profile</b></a></p></li></ul><p>Each TTML profile is defined in terms of a <a href="#terms-profile-definition-document">profile definition document</a>,
-which is expressed as an XML document wherein the root element adheres to
-<a href="#profile-vocabulary-profile"><b>6.1.1 ttp:profile</b></a>.</p><div class="div2">
-<h3><a id="profile-ttml2-full"></a>G.1 TTML2 Full Profile</h3><p>The TTML2 Full Profile is intended to be used to
-express maximum compliance for both transformation and presentation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This profile is a superset of the
-<a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml1/spec/ttml1.html#profile-dfxp-full">DFXP Full Profile</a>:
-it requires support for the
-<a href="#feature-version"><code>#border</code></a>,
-<a href="#feature-version"><code>#textOrientation</code></a>, and
-<a href="#feature-version"><code>#version</code></a>
-features.</p></div><div class="exampleInner"><pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
-&lt;!-- this file defines the "dfxp-full" profile of ttml --&gt;
-&lt;profile xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
-  &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-    &lt;!-- required (mandatory) feature support --&gt;
-    &lt;feature value="required"&gt;#animation&lt;/feature&gt;
-    &lt;feature value="required"&gt;#backgroundColor-block&lt;/feature&gt;
-    &lt;feature value="required"&gt;#backgroundColor-inline&lt;/feature&gt;
-    &lt;feature value="required"&gt;#backgroundColor-region&lt;/feature&gt;
-    &lt;feature value="required"&gt;#backgroundColor&lt;/feature&gt;
-    &lt;feature value="required"&gt;#bidi&lt;/feature&gt;
-    &lt;feature value="required"&gt;#border&lt;/feature&gt;
-    &lt;feature value="required"&gt;#cellResolution&lt;/feature&gt;
-    &lt;feature value="required"&gt;#clockMode-gps&lt;/feature&gt;
-    &lt;feature value="required"&gt;#clockMode-local&lt;/feature&gt;
-    &lt;feature value="required"&gt;#clockMode-utc&lt;/feature&gt;
-    &lt;feature value="required"&gt;#clockMode&lt;/feature&gt;
-    &lt;feature value="required"&gt;#color&lt;/feature&gt;
-    &lt;feature value="required"&gt;#content&lt;/feature&gt;
-    &lt;feature value="required"&gt;#core&lt;/feature&gt;
-    &lt;feature value="required"&gt;#direction&lt;/feature&gt;
-    &lt;feature value="required"&gt;#display-block&lt;/feature&gt;
-    &lt;feature value="required"&gt;#display-inline&lt;/feature&gt;
-    &lt;feature value="required"&gt;#display-region&lt;/feature&gt;
-    &lt;feature value="required"&gt;#display&lt;/feature&gt;
-    &lt;feature value="required"&gt;#displayAlign&lt;/feature&gt;
-    &lt;feature value="required"&gt;#dropMode-dropNTSC&lt;/feature&gt;
-    &lt;feature value="required"&gt;#dropMode-dropPAL&lt;/feature&gt;
-    &lt;feature value="required"&gt;#dropMode-nonDrop&lt;/feature&gt;
-    &lt;feature value="required"&gt;#dropMode&lt;/feature&gt;
-    &lt;feature value="required"&gt;#extent-region&lt;/feature&gt;
-    &lt;feature value="required"&gt;#extent-root&lt;/feature&gt;
-    &lt;feature value="required"&gt;#extent&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontFamily-generic&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontFamily-non-generic&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontFamily&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontSize-anamorphic&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontSize-isomorphic&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontSize&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontStyle-italic&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontStyle-oblique&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontStyle&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontWeight-bold&lt;/feature&gt;
-    &lt;feature value="required"&gt;#fontWeight&lt;/feature&gt;
-    &lt;feature value="required"&gt;#frameRate&lt;/feature&gt;
-    &lt;feature value="required"&gt;#frameRateMultiplier&lt;/feature&gt;
-    &lt;feature value="required"&gt;#layout&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length-cell&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length-em&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length-integer&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length-negative&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length-percentage&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length-pixel&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length-positive&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length-real&lt;/feature&gt;
-    &lt;feature value="required"&gt;#length&lt;/feature&gt;
-    &lt;feature value="required"&gt;#lineBreak-uax14&lt;/feature&gt;
-    &lt;feature value="required"&gt;#lineHeight&lt;/feature&gt;
-    &lt;feature value="required"&gt;#markerMode-continuous&lt;/feature&gt;
-    &lt;feature value="required"&gt;#markerMode-discontinuous&lt;/feature&gt;
-    &lt;feature value="required"&gt;#markerMode&lt;/feature&gt;
-    &lt;feature value="required"&gt;#metadata&lt;/feature&gt;
-    &lt;feature value="required"&gt;#nested-div&lt;/feature&gt;
-    &lt;feature value="required"&gt;#nested-span&lt;/feature&gt;
-    &lt;feature value="required"&gt;#opacity&lt;/feature&gt;
-    &lt;feature value="required"&gt;#origin&lt;/feature&gt;
-    &lt;feature value="required"&gt;#overflow-visible&lt;/feature&gt;
-    &lt;feature value="required"&gt;#overflow&lt;/feature&gt;
-    &lt;feature value="required"&gt;#padding-1&lt;/feature&gt;
-    &lt;feature value="required"&gt;#padding-2&lt;/feature&gt;
-    &lt;feature value="required"&gt;#padding-3&lt;/feature&gt;
-    &lt;feature value="required"&gt;#padding-4&lt;/feature&gt;
-    &lt;feature value="required"&gt;#padding&lt;/feature&gt;
-    &lt;feature value="required"&gt;#pixelAspectRatio&lt;/feature&gt;
-    &lt;feature value="required"&gt;#presentation&lt;/feature&gt;
-    &lt;feature value="required"&gt;#profile&lt;/feature&gt;
-    &lt;feature value="required"&gt;#showBackground&lt;/feature&gt;
-    &lt;feature value="required"&gt;#structure&lt;/feature&gt;
-    &lt;feature value="required"&gt;#styling-chained&lt;/feature&gt;
-    &lt;feature value="required"&gt;#styling-inheritance-content&lt;/feature&gt;
-    &lt;feature value="required"&gt;#styling-inheritance-region&lt;/feature&gt;
-    &lt;feature value="required"&gt;#styling-inline&lt;/feature&gt;
-    &lt;feature value="required"&gt;#styling-nested&lt;/feature&gt;
-    &lt;feature value="required"&gt;#styling-referential&lt;/feature&gt;
-    &lt;feature value="required"&gt;#styling&lt;/feature&gt;
-    &lt;feature value="required"&gt;#subFrameRate&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textAlign-absolute&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textAlign-relative&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textAlign&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textDecoration-over&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textDecoration-through&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textDecoration-under&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textDecoration&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textOrientation&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textOutline-blurred&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textOutline-unblurred&lt;/feature&gt;
-    &lt;feature value="required"&gt;#textOutline&lt;/feature&gt;
-    &lt;feature value="required"&gt;#tickRate&lt;/feature&gt;
-    &lt;feature value="required"&gt;#time-clock-with-frames&lt;/feature&gt;
-    &lt;feature value="required"&gt;#time-clock&lt;/feature&gt;
-    &lt;feature value="required"&gt;#time-offset-with-frames&lt;/feature&gt;
-    &lt;feature value="required"&gt;#time-offset-with-ticks&lt;/feature&gt;
-    &lt;feature value="required"&gt;#time-offset&lt;/feature&gt;
-    &lt;feature value="required"&gt;#timeBase-clock&lt;/feature&gt;
-    &lt;feature value="required"&gt;#timeBase-media&lt;/feature&gt;
-    &lt;feature value="required"&gt;#timeBase-smpte&lt;/feature&gt;
-    &lt;feature value="required"&gt;#timeContainer&lt;/feature&gt;
-    &lt;feature value="required"&gt;#timing&lt;/feature&gt;
-    &lt;feature value="required"&gt;#transformation&lt;/feature&gt;
-    &lt;feature value="required"&gt;#unicodeBidi&lt;/feature&gt;
-    &lt;feature value="required"&gt;#version&lt;/feature&gt;
-    &lt;feature value="required"&gt;#visibility-block&lt;/feature&gt;
-    &lt;feature value="required"&gt;#visibility-inline&lt;/feature&gt;
-    &lt;feature value="required"&gt;#visibility-region&lt;/feature&gt;
-    &lt;feature value="required"&gt;#visibility&lt;/feature&gt;
-    &lt;feature value="required"&gt;#wrapOption&lt;/feature&gt;
-    &lt;feature value="required"&gt;#writingMode-horizontal-lr&lt;/feature&gt;
-    &lt;feature value="required"&gt;#writingMode-horizontal-rl&lt;/feature&gt;
-    &lt;feature value="required"&gt;#writingMode-horizontal&lt;/feature&gt;
-    &lt;feature value="required"&gt;#writingMode-vertical&lt;/feature&gt;
-    &lt;feature value="required"&gt;#writingMode&lt;/feature&gt;
-    &lt;feature value="required"&gt;#zIndex&lt;/feature&gt;
-    &lt;!-- optional (voluntary) feature support --&gt;
-  &lt;/features&gt;
-  &lt;extensions xml:base="http://www.w3.org/ns/ttml/extension/"&gt;
-    &lt;!-- required (mandatory) extension support --&gt;
-    &lt;!-- optional (voluntary) extension support --&gt;
-  &lt;/extensions&gt;
-&lt;/profile&gt;
-
-</pre></div></div><div class="div2">
-<h3><a id="profile-ttml2-presentation"></a>G.2 TTML2 Presentation Profile</h3><p>The TTML2 Presentation Profile is intended to be used to
-express minimum compliance for presentation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This profile is a superset of the
-<a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml1/spec/ttml1.html#profile-dfxp-presentation">DFXP Presentation Profile</a>:
-it requires support for the <a href="#feature-version"><code>#version</code></a> feature.</p></div><div class="exampleInner"><pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
-&lt;!-- this file defines the "dfxp-presentation" profile of ttml --&gt;
-&lt;profile xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
-  &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-    &lt;!-- required (mandatory) feature support --&gt;
-    &lt;feature value="required"&gt;#content&lt;/feature&gt;
-    &lt;feature value="required"&gt;#core&lt;/feature&gt;
-    &lt;feature value="required"&gt;#presentation&lt;/feature&gt;
-    &lt;feature value="required"&gt;#profile&lt;/feature&gt;
-    &lt;feature value="required"&gt;#structure&lt;/feature&gt;
-    &lt;feature value="required"&gt;#time-offset&lt;/feature&gt;
-    &lt;feature value="required"&gt;#timing&lt;/feature&gt;
-    &lt;feature value="required"&gt;#version&lt;/feature&gt;
-    &lt;!-- optional (voluntary) feature support --&gt;
-    &lt;feature value="optional"&gt;#animation&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#backgroundColor-block&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#backgroundColor-inline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#backgroundColor-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#backgroundColor&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#bidi&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#border&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#cellResolution&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#clockMode-gps&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#clockMode-local&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#clockMode-utc&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#clockMode&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#color&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#direction&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#display-block&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#display-inline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#display-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#display&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#displayAlign&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#dropMode-dropNTSC&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#dropMode-dropPAL&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#dropMode-nonDrop&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#dropMode&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#extent-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#extent-root&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#extent&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontFamily-generic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontFamily-non-generic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontFamily&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontSize-anamorphic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontSize-isomorphic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontSize&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontStyle-italic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontStyle-oblique&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontStyle&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontWeight-bold&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontWeight&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#frameRate&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#frameRateMultiplier&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#layout&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-cell&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-em&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-integer&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-negative&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-percentage&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-pixel&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-positive&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-real&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#lineBreak-uax14&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#lineHeight&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#markerMode-continuous&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#markerMode-discontinuous&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#markerMode&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#metadata&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#nested-div&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#nested-span&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#opacity&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#origin&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#overflow-visible&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#overflow&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding-1&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding-2&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding-3&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding-4&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#pixelAspectRatio&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#showBackground&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-chained&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-inheritance-content&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-inheritance-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-inline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-nested&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-referential&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#subFrameRate&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textAlign-absolute&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textAlign-relative&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textAlign&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textDecoration-over&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textDecoration-through&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textDecoration-under&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textDecoration&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textOrientation&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textOutline-blurred&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textOutline-unblurred&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textOutline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#tickRate&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#time-clock-with-frames&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#time-clock&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#time-offset-with-frames&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#time-offset-with-ticks&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#timeBase-clock&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#timeBase-media&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#timeBase-smpte&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#timeContainer&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#transformation&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#unicodeBidi&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#visibility-block&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#visibility-inline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#visibility-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#visibility&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#wrapOption&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode-horizontal-lr&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode-horizontal-rl&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode-horizontal&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode-vertical&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#zIndex&lt;/feature&gt;
-  &lt;/features&gt;
-  &lt;extensions xml:base="http://www.w3.org/ns/ttml/extension/"&gt;
-    &lt;!-- required (mandatory) extension support --&gt;
-    &lt;!-- optional (voluntary) extension support --&gt;
-  &lt;/extensions&gt;
-&lt;/profile&gt;
-
-</pre></div></div><div class="div2">
-<h3><a id="profile-ttml2-transformation"></a>G.3 TTML2 Transformation Profile</h3><p>The TTML2 Transformation Profile is intended to be used to
-express minimum compliance for transformation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This profile is a superset of the
-<a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml1/spec/ttml1.html#profile-dfxp-transformation">DFXP Transformation Profile</a>:
-it requires support for the <a href="#feature-version"><code>#version</code></a> feature.</p></div><div class="exampleInner"><pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
-&lt;!-- this file defines the "dfxp-transformation" profile of ttml --&gt;
-&lt;profile xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
-  &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
-    &lt;!-- required (mandatory) feature support --&gt;
-    &lt;feature value="required"&gt;#content&lt;/feature&gt;
-    &lt;feature value="required"&gt;#core&lt;/feature&gt;
-    &lt;feature value="required"&gt;#profile&lt;/feature&gt;
-    &lt;feature value="required"&gt;#structure&lt;/feature&gt;
-    &lt;feature value="required"&gt;#time-offset&lt;/feature&gt;
-    &lt;feature value="required"&gt;#timing&lt;/feature&gt;
-    &lt;feature value="required"&gt;#transformation&lt;/feature&gt;
-    &lt;feature value="required"&gt;#version&lt;/feature&gt;
-    &lt;!-- optional (voluntary) feature support --&gt;
-    &lt;feature value="optional"&gt;#animation&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#backgroundColor-block&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#backgroundColor-inline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#backgroundColor-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#backgroundColor&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#bidi&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#border&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#cellResolution&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#clockMode-gps&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#clockMode-local&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#clockMode-utc&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#clockMode&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#color&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#direction&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#display-block&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#display-inline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#display-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#display&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#displayAlign&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#dropMode-dropNTSC&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#dropMode-dropPAL&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#dropMode-nonDrop&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#dropMode&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#extent-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#extent-root&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#extent&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontFamily-generic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontFamily-non-generic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontFamily&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontSize-anamorphic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontSize-isomorphic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontSize&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontStyle-italic&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontStyle-oblique&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontStyle&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontWeight-bold&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#fontWeight&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#frameRate&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#frameRateMultiplier&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#layout&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-cell&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-em&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-integer&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-negative&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-percentage&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-pixel&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-positive&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length-real&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#length&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#lineBreak-uax14&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#lineHeight&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#markerMode-continuous&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#markerMode-discontinuous&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#markerMode&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#metadata&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#nested-div&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#nested-span&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#opacity&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#origin&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#overflow-visible&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#overflow&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding-1&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding-2&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding-3&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding-4&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#padding&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#pixelAspectRatio&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#presentation&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#showBackground&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-chained&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-inheritance-content&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-inheritance-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-inline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-nested&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling-referential&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#styling&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#subFrameRate&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textAlign-absolute&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textAlign-relative&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textAlign&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textDecoration-over&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textDecoration-through&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textDecoration-under&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textDecoration&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textOrientation&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textOutline-blurred&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textOutline-unblurred&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#textOutline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#tickRate&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#time-clock-with-frames&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#time-clock&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#time-offset-with-frames&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#time-offset-with-ticks&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#timeBase-clock&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#timeBase-media&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#timeBase-smpte&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#timeContainer&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#unicodeBidi&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#visibility-block&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#visibility-inline&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#visibility-region&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#visibility&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#wrapOption&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode-horizontal-lr&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode-horizontal-rl&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode-horizontal&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode-vertical&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#writingMode&lt;/feature&gt;
-    &lt;feature value="optional"&gt;#zIndex&lt;/feature&gt;
-  &lt;/features&gt;
-  &lt;extensions xml:base="http://www.w3.org/ns/ttml/extension/"&gt;
-    &lt;!-- required (mandatory) extension support --&gt;
-    &lt;!-- optional (voluntary) extension support --&gt;
-  &lt;/extensions&gt;
-&lt;/profile&gt;
-
-</pre></div></div></div><div class="div1">
-<h2><a id="time-expression-semantics"></a>H Time Expression Semantics</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the semantics for interpreting time expressions in <a href="#terms-document-instance">document instances</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The phrase <em>local real time</em> as used below is intended to model a virtual real time clock in the document processing context, where
-<em>local</em> means in the immediate proximity of the implementation of this processing context. The intent
-of defining relationships with this virtual clock is to establish a locally valid physical realization of time for didactic purposes.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The phrase <em>play rate</em> as used below is intended to model a (possibly variable) parameter in the document processing context wherein
-the rate of playback (or interpretation) of time may artificially dilated or narrowed, for example, when slowing down or speeding up the rate of
-playback of a <a href="#terms-related-media-object">related media object</a>. Without loss of generality, the following discussion assumes a fixed play(back) rate. In the case of
-variable play rates, appropriate adjustments may need to be made to the resulting computations.</p></div><div class="div2">
-<h3><a id="time-expression-semantics-clock"></a>H.1 Clock Time Base</h3><p>When operating with the <code>clock</code> time base, the following semantics apply for interpreting time expressions,
-as defined by <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, and their relationship to media time and local real time.</p><p>The clock time base <span class="strong"><code>C</code></span> is related to local real time <span class="strong"><code>R</code></span>
-expressed in an arbitrary (implementation defined) epoch <span class="strong"><code>E</code></span>
-as follows:</p><a id="clock-time-and-real-time"></a><table class="semantics"><caption>TTML Semantics – Clock Time and Real Time Relationship</caption><tbody><tr><td>
-<blockquote><p><br>
-<code>R = C + epochOffset + discontinuityOffset</code>
-<br><br>
-where <code>C ∈ ℜ</code>, <code>0 ≤ C &lt; ∞</code>, <code>C</code> in seconds since the most immediately prior midnight of the reference clock base;
-<br><br>
-<code>epochOffset ∈ ℜ</code>, <code>0 ≤ epochOffset &lt; ∞</code>, <code>epochOffset</code> in seconds, with 0 being the beginning
-of epoch <code>E</code>, and where the value of <code>epochOffset</code> is determined from the computed value of the <code>ttp:clockMode</code> parameter
-as follows:
-<br><br>
-(1) if <code>local</code>, then the difference between the local real time at the most immediately prior local midnight and the local real time
-at the beginning of epoch <code>E</code>, expressed in seconds;
-<br><br>
-(2) if <code>gps</code>, then the difference between the GPS time at the most immediately prior GPS midnight
-and the GPS time at the beginning of epoch <code>E</code>, expressed in seconds;
-<br><br>
-(3) if <code>utc</code>, then the difference between the UTC time at the most immediately prior UTC midnight
-and the UTC time at the beginning of epoch <code>E</code>, expressed in seconds;
-<br><br>
-<code>discontinuityOffset ∈ ℜ</code>, <code>−∞ &lt; discontinuityOffset &lt; ∞</code>, <code>discontinuityOffset</code> in seconds,
-and where the value of <code>discontinuityOffset</code> is equal to the sum of leap seconds (and fractions thereof) that have been added (or subtracted) since the
-most immediately prior midnight in the reference clock base;
-<br><br>
-and <code>epochOffset</code> and <code>discontinuityOffset</code> are determined once and only once prior to the beginning of the <a href="#terms-root-temporal-extent">root temporal extent</a> such that
-during the period between value determination and the beginning of the <a href="#terms-root-temporal-extent">root temporal extent</a> there occurs no local midnight or reference clock base discontinuity.
-<br></p></blockquote>
-</td></tr></tbody></table><p>Time value expressions, as denoted by a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, are related to
-clock time <span class="strong"><code>C</code></span> as follows:</p><a id="time-expressions-and-clock-time"></a><table class="semantics"><caption>TTML Semantics – Time Expressions and Clock Time Relationship</caption><tbody><tr><td>
-<blockquote><p><br>
-If a time expression uses the <em>clock-time</em> form or an <em>offset-time</em> form that doesn't use the ticks (<code>t</code>) metric, then:
-<br><br>
-<code>C = 3600 * hours + 60 * minutes + seconds</code>
-<br><br>
-where
-<code>hours</code>,
-<code>minutes</code>,
-<code>seconds</code> components are extracted from time expression if present, or zero if not present.
-<br><br>
-Otherwise, if a time expression uses an <em>offset-time</em> form that uses the ticks (<code>t</code>) metric, then:
-<br><br>
-<code>C = ticks / tickRate</code>
-<br></p></blockquote>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The <em>frames</em> and <em>sub-frames</em> terms and the frames (<code>f</code>) metric of time expressions do not apply when using
-the <code>clock</code> time base.</p></div><p>The clock time base <span class="strong"><code>C</code></span> is independent of media time <span class="strong"><code>M</code></span>:</p><a id="clock-time-and-media-time"></a><table class="semantics"><caption>TTML Semantics – Clock Time and Media Time Relationship</caption><tbody><tr><td>
-<blockquote><p><br>
-<code>M ¬∝ C</code>
-<br></p></blockquote>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>That is to say, timing is disconnected from (not necessarily proportional to) media time when
-the <code>clock</code> time base is used. For example, if the media play rate is zero (0), media playback is suspended; however, timing coordinates
-will continue to advance according to the natural progression of clock time in direct proportion to the reference clock base. Furthermore, if the media play rate changes
-during playback, presentation timing is not affected.
-</p></div></div><div class="div2">
-<h3><a id="time-expression-semantics-media"></a>H.2 Media Time Base</h3><p>When operating with the <code>media</code> time base, the following semantics apply for interpreting time expressions,
-as defined by <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, and their relationship to media time and local real time.</p><div class="issue"><p class="prefix"><a id="issue-306"></a><b>Issue (issue-306):</b></p><p class="prefix"><b>Fractional Time Expressions</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/306">http://www.w3.org/AudioVideo/TT/tracker/issues/306</a></p><p>Augment syntax to cover fractional time expressions.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>The media time base <span class="strong"><code>M</code></span> is related to local real time <span class="strong"><code>R</code></span>
-expressed in an arbitrary (implementation defined) epoch <span class="strong"><code>E</code></span> as follows:</p><a id="media-time-and-real-time"></a><table class="semantics"><caption>TTML Semantics – Media Time and Real Time Relationship</caption><tbody><tr><td>
-<blockquote><p><br>
-<code>R = playRate * M + epochOffset</code>
-<br><br>
-where <code>M ∈ ℜ</code>, <code>0 ≤ M &lt; ∞</code>, <code>M</code> in seconds, with 0 corresponding to the beginning of the <a href="#terms-root-temporal-extent">root temporal extent</a>;
-<br><br>
-<code>playRate ∈ ℜ</code>, <code>−∞ &lt; playRate &lt; ∞</code>, <code>playRate</code> is unit-less, and where the value of
-<code>playRate</code> is determined by the document processing context;
-<br><br>
-and <code>epochOffset ∈ ℜ</code>, <code>0 ≤ epochOffset &lt; ∞</code>, <code>epochOffset</code> in seconds, with 0 corresponding to the beginning of
-an epoch <code>E</code>, and where the value of <code>epochOffset</code> is the difference between the local real time at the beginning of the
-<a href="#terms-root-temporal-extent">root temporal extent</a> and the local real time at the the beginning of epoch <code>E</code>, expressed in seconds.
-</p></blockquote>
-</td></tr></tbody></table><p>Time value expressions, as denoted by a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, are related to
-media time <span class="strong"><code>M</code></span> in accordance to the
-<code>ttp:frameRate</code>, <code>ttp:subFrameRate</code>, and <code>ttp:frameRateMultipler</code> parameters as follows:</p><a id="time-expressions-and-media-time"></a><table class="semantics"><caption>TTML Semantics – Time Expressions and Media Time Relationship</caption><tbody><tr><td>
-<blockquote><p><br>
-If a time expression uses a <em>clock-time</em> form or an <em>offset-time</em> form that doesn't use the ticks (<code>t</code>) metric, then:
-<br><br>
-<code>
-M = referenceBegin + 3600 * hours + 60 * minutes + seconds + ((frames + (subFrames / subFrameRate)) / effectiveFrameRate)
-</code>
-<br><br>
-where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
-parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
-timed element exists, then <code>referenceBegin</code>
-is the media time that corresponds to the beginning of the nearest ancestor time container or
-zero (0) if this time container is the <a href="#terms-root-temporal-extent">root temporal extent</a>; otherwise, if sequential and a prior sibling
-timed element exists, then <code>referenceBegin</code> is the media time that corresponds to the active end of the
-immediate prior sibling timed element;
-<br><br>
-the <code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
-are extracted from time expression if present, or zero if not present;
-<br><br>
-<code>subFrameRate</code> is the computed value of the <code>ttp:subFrameRate</code> parameter;
-<br><br>
-and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
-<code>frameRate</code> is the computed value of the <code>ttp:frameRate</code> parameter and
-<code>frameRateMultipler</code> is the computed value of the <code>ttp:frameRateMultiplier</code> parameter.
-<br><br>
-Otherwise, if a time expression uses an <em>offset-time</em> form that uses the ticks (<code>t</code>) metric, then:
-<br><br>
-<code>
-M = referenceBegin + ticks / tickRate
-</code>
-<br><br>
-where <code>referenceBegin</code> is as described above;
-<br><br>
-the <code>ticks</code> component is extracted from time expression;
-<br><br>
-and <code>tickRate</code> is the computed value of the <code>ttp:tickRate</code> parameter;
-<br></p></blockquote>
-</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>If the computed <code>frameRateMultipler</code> ratio is not integral, then <code>effectiveFrameRate</code> will be a non-integral rational.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a> is related to the begin time of a
-<a href="#terms-related-media-object">related media object</a> in accordance with the computed value of the
-<a href="#parameter-attribute-mediaOffset"><code>ttp:mediaOffset</code></a> parameter property.</p></div></div><div class="div2">
-<h3><a id="time-expression-semantics-smpte"></a>H.3 SMPTE Time Base</h3><p>When operating with the <code>smpte</code> time base, the following semantics apply for interpreting time expressions,
-as defined by <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, and their relationship to media time and local real time.</p><div class="issue"><p class="prefix"><a id="issue-322"></a><b>Issue (issue-322):</b></p><p class="prefix"><b>Incorrect Expression for NTSC Drop Mode</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/322">http://www.w3.org/AudioVideo/TT/tracker/issues/322</a></p><p>Correct formula for NTSC drop mode calculation.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If the computed value of the <code>ttp:markerMode</code> parameter is <code>discontinuous</code>, then there is no direct relationship between
-time expressions and media time <span class="strong"><code>M</code></span> or local real time <span class="strong"><code>R</code></span>. In
-this case, time expressions refer to synchronization events (markers) emitted by the <a href="#terms-document-processing-context">document processing context</a>
-when <a href="#terms-smpte-time-code">smpte time codes</a>
-are encountered in the <a href="#terms-related-media-object">related media object</a>.</p><p>Otherwise, if the computed value of the <code>ttp:markerMode</code> parameter is <code>continuous</code>, then the relationships between time expressions and
-local real time and media time are as described below in terms of a <a href="#terms-synthetic-smpte-document-syncbase">synthetic smpte document syncbase</a>, here referred to as the
-SMPTE time base <span class="strong"><code>S</code></span>.</p><a id="time-expressions-and-smpte-time"></a><table class="semantics"><caption>TTML Semantics – Time Expressions and SMPTE Time Relationship</caption><tbody><tr><td>
-<blockquote><p><br>
-<code>S = (countedFrames - droppedFrames + (subFrames / subFrameRate)) / effectiveFrameRate</code>
-<br><br>where<br><br>
-<code>countedFrames = (3600 * hours + 60 * minutes + seconds) * frameRate + frames</code>
-<br><br>
-<code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
-are extracted from time expression if present, or zero if not present;
-<br><br>
-<code>droppedFrames</code> is computed as follows:
-<br><br>
-1. let <em>dropMode</em> be the computed value of the <code>ttp:dropMode</code> parameter;
-<br><br>
-2. if <em>dropMode</em> is <code>dropNTSC</code>, let
-<code>droppedFrames = (hours * 54 + floor(minutes - minutes/10)) * 2</code>;
-<br><br>
-3. otherwise, if <em>dropMode</em> is <code>dropPAL</code>, let
-<code>droppedFrames = (hours * 27 + floor(minutes/2 - minutes/20)) * 4</code>;
-<br><br>
-4. otherwise, let
-<code>droppedFrames = 0</code>;
-<br><br>
-<code>frameRate</code> is the computed value of the <code>ttp:frameRate</code> parameter;
-<br><br>
-<code>subFrameRate</code> is the computed value of the <code>ttp:subFrameRate</code> parameter;
-<br><br>
-and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
-<code>frameRate</code> is the computed value of the <code>ttp:frameRate</code> parameter and
-<code>frameRateMultipler</code> is the computed value of the <code>ttp:frameRateMultiplier</code> parameter.
-<br><br>
-Notwithstanding the above, if a time expression contains a frame code that is designated as
-dropped according to <a href="#parameter-attribute-dropMode"><b>7.2.3 ttp:dropMode</b></a>, then that time expression
-must be considered to be invalid for purposes of validation assessment.
-<br></p></blockquote>
-</td></tr></tbody></table><p>The SMPTE time base <span class="strong"><code>S</code></span> is related to the media time base <span class="strong"><code>M</code></span> as follows:</p><a id="smpte-time-and-media-time"></a><table class="semantics"><caption>TTML Semantics – SMPTE Time and Media Time Relationship</caption><tbody><tr><td>
-<blockquote><p><br>
-<code>M = referenceBegin + S</code>
-<br><br>
-where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
-parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
-timed element exists, then <code>referenceBegin</code>
-is the SMPTE time that corresponds to the beginning of the nearest ancestor time container or
-zero (0) if this time container is the <a href="#terms-root-temporal-extent">root temporal extent</a>; otherwise, if sequential and a prior sibling
-timed element exists, then <code>referenceBegin</code> is the SMPTE time that corresponds to the active end of the
-immediate prior sibling timed element;
-<br></p></blockquote>
-</td></tr></tbody></table><p>Given the derived media time base as described above, then 
-media time base <span class="strong"><code>M</code></span> is related to the local real time <span class="strong"><code>R</code></span>
-as described in <a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> above.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a> is related to the begin time of a
-<a href="#terms-related-media-object">related media object</a> in accordance with the computed value of the
-<a href="#parameter-attribute-mediaOffset"><code>ttp:mediaOffset</code></a> parameter property.</p></div></div></div><div class="div1">
-<h2><a id="isd"></a>I Intermediate Document Syntax</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the syntactic elements and structure of a
-<a href="#terms-timed-text-intermediate-document">timed text intermediate document</a>.
-An ISD instance may be represented as a standalone document instance or
-in a collection represented as an ISD Sequence instance.</p><p>All ISD related vocabulary is defined in the TTML ISD Namespace, defined here as <code>http://www.w3.org/ns/ttml#isd</code>,
-where the recommended prefix is <code>isd</code>.</p><p>A TTML <a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>, in short, an <em>ISD</em> or <em>ISD instance</em>,
-represents a discrete, temporally non-overlapping interval, an <em>ISD interval</em>,
-of a source TTML document where, except for non-discrete animation, all content, styling, and layout information remains static within that interval.
-In particular, the timing hierarchy of a TTML document is flattened and then sub-divided into temporally non-overlapping intervals, where each such
-interval defines a static view of the source TTML document within that interval, and where that static view is represented as an ISD instance.
-A concrete, standalone instance of a TTML
-<a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a> must specify an
-<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element as its root document element. When an instance of a
-<a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a> is included in a
-<a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a> instance, then the ISD instance is represented
-by an <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> child element of the root 
-<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>An ISD instance may contain one or more animate elements that denote continuous animation within the associated interval. Continuously animated styles are sub-divided across
-ISD interval boundaries such that their step-wise concatenation expresses an equivalent continuous animation over any intersecting ISD interval(s).</p></div><p>A TTML <a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a> represents a collection
-of temporally non-overlapping <a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a> instances ordered according
-to their begin times. A concrete instance of a TTML
-<a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a> must specify an
-<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element as its root document element.</p><div class="div2">
-<h3><a id="isd-vocabulary"></a>I.1 ISD Vocabulary</h3><div class="div3">
-<h4><a id="isd-vocabulary-sequence"></a>I.1.1 isd:sequence</h4><p>The <code>isd:sequence</code> element serves as the root document element of an <a href="#terms-intermediate-synchronic-document-sequence">Intermediate
-Synchronic Document Sequence</a>  document.</p><p>The <code>isd:sequence</code> element accepts as its children zero or more elements in the
-<a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or one <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element,
-followed by zero or more <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> elements.</p><p>Child <code>isd:isd</code> elements must be ordered in accordance to the media time equivalent of their
-begin time; furthermore, the temporal intervals of any two child <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> elements must not overlap (in time).</p><a id="elt-syntax-isd-sequence"></a><table class="syntax"><caption>XML Representation – Element Information Item: isd:sequence</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;isd:sequence
-  size = <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>
-  version = <a href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</a>
-  <a href="#content-attribute-xml-lang"><span class="reqattr">xml:lang</span></a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  {<em>any attribute in the <a href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</a></em>}&gt;
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#profile-vocabulary-profile">ttp:profile</a>?, <a href="#isd-vocabulary-isd">isd:isd</a>*
-&lt;/isd:sequence&gt;
-</pre></div>
-</td></tr></tbody></table><p>If the <code>size</code> attribute is specified, then it must be a non-negative integer corresponding to the number of
-<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> child elements.
-If not specified, then the size must be considered to be <em>indefinite</em>, unless and until the
-<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element is terminated, in which case the size
-may be determined by inspection.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The <code>size</code> attribute would normally be omitted in the case of real time captioning.</p></div><p>If the <code>version</code> attribute is specified, then it must be a positive integer corresponding to the version of this
-<a href="#terms-intermediate-synchronic-document-syntax">Intermediate Synchronic Document Syntax</a> specification used in authoring
-the ISD sequence document. If specified, the numeric value must be greater than or equal to two (2). If not specified, then the version must be
-consider to be equal to two (2). The version associated with this
-<a href="#terms-intermediate-synchronic-document-sequence-syntax">Intermediate Synchronic Document Sequence Syntax</a> specification is two (2).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The ISD abstraction referred to or implied by <a href="#ttml1">[TTML1]</a> §9.3.2 was not concretely defined by that specification. Here we reserve version one (1)
-for informal discussion of that earlier abstraction and its various (non-standardized) realizations.</p></div><p>An <a href="#content-attribute-xml-lang"><code>xml:lang</code></a> attribute must be specified on the
-<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element.
-If its value is empty, it signifies that there is no default language that applies
-to the content within the <a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a>. Otherwise,
-the specified value denotes the default language that applies to each constituent
-<a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>.</p><p>One or more parameter properties may be specified from the restricted parameter attribute set enumerated in <a href="#isd-parameter-attribute-set"><b>I.2 ISD Parameter Attribute Set</b></a>.
-If specified, then they apply globally to each constituent <a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>.</p><p>If a child <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element is present,
-then that <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element must satisfy the following constraints:</p><ul><li><p>no <code>combine</code> attribute is specified;</p></li><li><p>no <code>designator</code> attribute is specified;</p></li><li><p>no <code>type</code> attribute is specified;</p></li><li><p>no <code>use</code> attribute is specified;</p></li><li><p>no descendant element is a <code>ttp:profile</code> element;</p></li><li><p>no descendant <code>ttp:feature</code> element specifies a <code>value</code> attribute with the value <code>prohibited</code>;</p></li><li><p>no descendant <code>ttp:extension</code> element specifies a <code>value</code> attribute with the value <code>prohibited</code>.</p></li></ul><p>Furthermore, such a child <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element must specify a profile that is equivalent to the combined
-<a href="#terms-processor-profile">processor profile</a> of the source TTML document having fetched all externally referenced profile documents.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The intent of permitting a single <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> to be specified in an
-<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> is to provide a simplified mechanism to declare
-processor profile requirements that must be met in order to process the document (in the absence of an end-user override).</p></div></div><div class="div3">
-<h4><a id="isd-vocabulary-isd"></a>I.1.2 isd:isd</h4><p>The <code>isd:isd</code> element serves either as (1) the root document element of a standalone <a href="#terms-intermediate-synchronic-document">Intermediate
-Synchronic Document</a> or (2) as a child of an <a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element of a
-<a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a> document.</p><p>The <code>isd:isd</code> element accepts as its children zero or more elements in the
-<a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or one <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element,
-followed by zero or more <a href="#isd-vocabulary-css"><code>isd:css</code></a> elements,
-followed by zero or more <a href="#isd-vocabulary-region"><code>isd:region</code></a> elements.</p><a id="elt-syntax-isd"></a><table class="syntax"><caption>XML Representation – Element Information Item: isd:isd</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;isd:isd
-  <a href="#timing-attribute-begin"><span class="reqattr">begin</span></a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  <a href="#timing-attribute-end"><span class="reqattr">end</span></a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
-  version = <a href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</a>
-  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  {<em>any attribute in the <a href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</a></em>}&gt;
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#profile-vocabulary-profile">ttp:profile</a>?, <a href="#isd-vocabulary-css">isd:css</a>*, <a href="#isd-vocabulary-region">isd:region</a>*
-&lt;/isd:isd&gt;
-</pre></div>
-</td></tr></tbody></table><p>A <code>begin</code> attribute must be specified, the value of which must take the <em>offset-time</em> form of
-a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, and, further, is restricted to use a metric of
-<code>s</code> (seconds),
-<code>f</code> (frames),
-<code>t</code> (ticks), or may omit the metric, in which case <code>s</code> seconds is implied. This
-begin time is expressed as an offset from the begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a>
-of the source TTML document from which this <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element was derived.</p><p>An <code>end</code> attribute must be similarlly specified, where the same constraints apply.
-This end time is expressed as an offset from the begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a>
-of the source TTML document from which this <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element was derived.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Expressed in the terminology of <a href="#smil3">[SMIL 3.0]</a>, the values of these <code>begin</code> and <code>end</code> attributes
-correspond to the resolved begin and end times of the <em>active duration</em> with respect to the <em>document begin</em>.</p></div><p>An <a href="#content-attribute-xml-lang"><code>xml:lang</code></a> attribute must be specified on the
-<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element if it is a standalone <a href="#terms-intermediate-synchronic-document">Intermediate
-Synchronic Document</a> document; otherwise, it may be specified, and should be specified if the default language of the 
-<a href="#isd-vocabulary-sequence"><code>isd:isd</code></a> element differs from the default language of its
-parent <a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element.
-If its value is empty, it signifies that there is no default language that applies
-to the content within the <a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>. Otherwise,
-the specified value denotes the default language that applies.</p><p>The <code>version</code> attribute follows the syntax and semantics of the same named attribute on the
-<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element type. The <code>version</code>
-attribute must not be specified on an <a href="#isd-vocabulary-isd">isd:isd</a> element that is not
-a root document element, i.e., is a child element of an <a href="#isd-vocabulary-sequence">isd:sequence</a> element.</p><p>A child <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element may be present if the
-<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element is a standalone <a href="#terms-intermediate-synchronic-document">Intermediate
-Synchronic Document</a> document, in which case the same constraints and semantics apply as specified in <a href="#isd-vocabulary-sequence"><b>I.1.1 isd:sequence</b></a>;
-otherwise, if not a standalone document, a child <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element must not be present.</p></div><div class="div3">
-<h4><a id="isd-vocabulary-css"></a>I.1.3 isd:css</h4><p>The <code>isd:css</code> element is used to represent a unique computed style set of some collection of elements
-that share the same set of computed styles. In particular, for each
-element <em>E</em> in the source TTML document which is selected and copied into a
-<a href="#isd-vocabulary-region"><code>isd:region</code></a> element of a given
-<a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>, the computed style
-set of <em>E</em>, <em>CSS(E)</em>, is determined, and, if that <em>CSS(E)</em> is not already specified
-by an existing <code>isd:css</code> element, then it is assigned a unique identifier and instantiated as a new
-<code>isd:css</code> element.</p><p>The <code>isd:css</code> element accepts as its children zero or more elements in the
-<a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group.</p><a id="elt-syntax-isd-style"></a><table class="syntax"><caption>XML Representation – Element Information Item: isd:css</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;isd:css
-  <a href="#content-attribute-xml-id"><span class="reqattr">xml:id</span></a> = ID
-  {<em>any attribute in TT Style namespace</em>}
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
-&lt;/isd:css&gt;
-</pre></div>
-</td></tr></tbody></table><p>For each arbitrary pair of <code>isd:css</code> child elements of an
-<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element,
-<em>S1</em> and <em>S2</em>, the set of specified styles of <em>S1</em> must
-not be the same as the set of specified styles of <em>S2</em>. For the purpose of comparing two
-sets of specified styles, the styles must be placed into a canonical order and then compared item
-by item for value equality, where the canonical order is in accordance to the qualified attribute name
-order, where each qualified name consists of a tuple <code>&lt;namespace URL, local name&gt;</code>,
-and such tuples are compared component-wise by case-sensitive lexical string order.</p></div><div class="div3">
-<h4><a id="isd-vocabulary-region"></a>I.1.4 isd:region</h4><p>The <code>isd:region</code> element is used to represent a layout and presentation region
-and the content selected into that region, where that content takes the form of a
-<a href="#document-structure-vocabulary-body">body</a> element and its descendant TTML content elements.</p><p>The <code>isd:region</code> element accepts as its children zero or more elements in the
-<a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
-followed by zero or more <a href="#animation-vocabulary-animate"><code>animate</code></a> elements,
-followed by exactly one <a href="#document-structure-vocabulary-body"><code>body</code></a> element.</p><a id="elt-syntax-isd-region"></a><table class="syntax"><caption>XML Representation – Element Information Item: isd:region</caption><tbody><tr><td>
-<div class="exampleInner"><pre>
-&lt;isd:region
-  <a href="#style-attribute-style">style</a> = IDREF
-  <a href="#metadata-attribute-role">ttm:role</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
-  <a href="#content-attribute-xml-id"><span class="reqattr">xml:id</span></a> = ID
-  {<em>any attribute not in default or any TT namespace</em>}&gt;
-  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#animation-vocabulary-animate">animate</a>*, <a href="#document-structure-vocabulary-body">body</a>
-&lt;/isd:region&gt;
-</pre></div>
-</td></tr></tbody></table><p>If the computed style set of the region represented by the <code>isd:region</code> element is not the
-set of initial style values that apply to <a href="#layout-vocabulary-region"><code>region</code></a>, then a
-<code>style</code> attribute must be specified which references an <a href="#isd-vocabulary-css"><code>isd:css</code></a> element that specifies the
-region's computed style set.</p><p>The following constraints apply to the <a href="#document-structure-vocabulary-body"><code>body</code></a> element
-and its descendant elements:</p><ul><li><p>no <code>animate</code> attribute is specified;</p></li><li><p>no <code>begin</code> attribute is specified;</p></li><li><p>no <code>dur</code> attribute is specified;</p></li><li><p>no <code>end</code> attribute is specified;</p></li><li><p>no <code>region</code> attribute is specified;</p></li><li><p>no <code>timeContainer</code> attribute is specified;</p></li><li><p>no attribute in the TT Style namespace is specified;</p></li><li><p>no <a href="#animation-vocabulary-set">set</a> element is present;</p></li><li><p>no significant text node, i.e., text node in a #PCDATA context, is not contained in a 
-<a href="#content-vocabulary-span"><code>span</code></a> element that contains no other child.</p></li></ul><p>In addition, for the <a href="#document-structure-vocabulary-body"><code>body</code></a> element <em>B</em> and
-each of its descendant content elements <em>C</em>, if the computed style set of <em>B</em> or each <em>C</em> is
-not equal to the computed style set of its parent element, then that element, <em>B</em> or <em>C</em>, must specify a <code>style</code>
-attribute that references an <a href="#isd-vocabulary-css"><code>isd:css</code></a> element that specifies the
-element's computed style set.</p></div></div><div class="div2">
-<h3><a id="isd-parameter-attribute-set"></a>I.2 ISD Parameter Attribute Set</h3><p>The following subset of the defined <a href="#attribute-vocab-group-parameters">Parameter Attributes</a>
-are available for use with an
-<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> or
-<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element as described above:</p><ul><li><p><a href="#parameter-attribute-cellResolution">ttp:cellResolution</a></p></li><li><p><a href="#parameter-attribute-frameRate">ttp:frameRate</a></p></li><li><p><a href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultipler</a></p></li><li><p><a href="#parameter-attribute-mediaOffset">ttp:mediaOffset</a></p></li><li><p><a href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</a></p></li><li><p><a href="#parameter-attribute-subFrameRate">ttp:subFrameRate</a></p></li><li><p><a href="#parameter-attribute-tickRate">ttp:tickRate</a></p></li></ul></div><div class="div2">
-<h3><a id="isd-interchange"></a>I.3 ISD Interchange</h3><p>A concrete document instance that employs the <a href="#isd">Intermediate Synchronic Document Syntax</a> must be
-encoded as a well-formed <a href="#xml10">[XML 1.0]</a> document using the UTF-8 character encoding. Furthermore, such a document must specify
-an <a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element or
-an <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element as the root document element.</p><p>When a resource consisting of a concrete ISD Sequence or ISD instance is interchanged and a media type is used to identify the content type
-of that resource, then the media type <code>application/ttml+xml</code> should be used, about which see <a href="#ttml1">[TTML1]</a> Appendix C.
-If this media type is used, the optional <code>profile</code> parameter must not be specified, or, if specified, must be ignored by a processor.</p></div><div class="div2">
-<h3><a id="isd-examples"></a>I.4 ISD Examples</h3><p><em>This sub-section is non-normative.</em></p><table border="1" class="ednote" summary="Editorial note: Add ISD Examples"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Add ISD Examples</b></td><td align="right" valign="top">2014-09-22</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add worked out examples of ISD Sequence and ISD document instances.</td></tr></table></div></div><div class="div1">
-<h2><a id="references"></a>J References</h2><p><em>This appendix is normative.</em></p><dl><dt class="label"><a id="css2"></a>CSS2</dt><dd>Bert Bos et al.,
-<a href="http://www.w3.org/TR/2011/REC-CSS2-20110607/"><cite>Cascading
-Style Sheets, Level 2 Revision 1</cite></a>, W3C Recommendation, 07 June 2011.
-(See <a href="http://www.w3.org/TR/2011/REC-CSS2-20110607/">http://www.w3.org/TR/2011/REC-CSS2-20110607/</a>.)
-</dd><dt class="label"><a id="css3-color"></a>CSS3 Color</dt><dd>Tantek Çelik and Chris Lilley,
-<a href="http://www.w3.org/TR/2011/REC-css3-color-20110607/"><cite>CSS Color
-Module Level 3</cite></a>, W3C Recommendation, 07 June 2011. (See
-<a href="http://www.w3.org/TR/2011/REC-css3-color-20110607/">http://www.w3.org/TR/2011/REC-css3-color-20110607/</a>.)
-</dd><dt class="label"><a id="data-encodings"></a>Data Encodings</dt><dd>S. Josefsson,
-<a href="http://www.rfc-editor.org/rfc/rfc4648.txt"><cite>The Base16, Base32, and Base64 Data Encodings</cite></a>,
-RFC 4648, October 2006, IETF. (See
-<a href="http://www.rfc-editor.org/rfc/rfc4648.txt">http://www.rfc-editor.org/rfc/rfc4648.txt</a>.)
-</dd><dt class="label"><a id="gps"></a>GPS</dt><dd>
-<a href="http://www.gps.gov/technical/"><cite>Global
-Positioning System</cite></a>, US Air Force.
-(See
-<a href="http://www.gps.gov/technical/">http://www.gps.gov/technical/</a>.)
-</dd><dt class="label"><a id="html5"></a>HTML5</dt><dd>Ian Hickson et al.,
-<a href="http://www.w3.org/TR/2014/REC-html5-20141028/"><cite>HTML5 A vocabulary and associated APIs for HTML and XHTML</cite></a>,
-W3C Recommendation, 28 October 2014. (See
-<a href="http://www.w3.org/TR/2014/REC-html5-20141028/">http://www.w3.org/TR/2014/REC-html5-20141028/</a>.)
-</dd><dt class="label"><a id="media-queries"></a>Media Queries</dt><dd>Florian Rivoal,,
-<a href="http://www.w3.org/TR/2012/REC-css3-mediaqueries-20120619/"><cite>Media Queries</cite></a>, W3C Recommendation, 19 June 2012. (See
-<a href="http://www.w3.org/TR/2012/REC-css3-mediaqueries-20120619/">http://www.w3.org/TR/2012/REC-css3-mediaqueries-20120619/</a>.)
-</dd><dt class="label"><a id="mime"></a>MIME</dt><dd>Ned Freed and Nathaniel Borenstein,  
-<a href="http://www.rfc-editor.org/rfc/rfc2045.txt"><cite>Multipurpose Internet
-Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite></a>,
-RFC 2045, November 1996, IETF.(See
-<a href="http://www.rfc-editor.org/rfc/rfc2045.txt">http://www.rfc-editor.org/rfc/rfc2045.txt</a>.)
-</dd><dt class="label"><a id="media-types"></a>MIME Media Types</dt><dd>Ned Freed and Nathaniel Borenstein,  
-<a href="http://www.rfc-editor.org/rfc/rfc2046.txt"><cite>Multipurpose Internet
-Mail Extensions (MIME) Part Two: Media Types</cite></a>,
-RFC 2046, November 1996, IETF.(See
-<a href="http://www.rfc-editor.org/rfc/rfc2046.txt">http://www.rfc-editor.org/rfc/rfc2046.txt</a>.)
-</dd><dt class="label"><a id="rng"></a>RELAX NG</dt><dd>ISO/IEC 19757-2,
-<a href="http://www.iso.org/"><cite>Information technology – Document
-Schema Definition Language (DSDL) – Part 2: Regular-grammar-based validation – RELAX NG</cite></a>,
-International Organization for Standardization (ISO).
-</dd><dt class="label"><a id="ruby"></a>Ruby</dt><dd>Masayasu Ishikawa et al.,
-<a href="http://www.w3.org/TR/2001/REC-ruby-20010531/"><cite>Ruby Annotation</cite></a>
-W3C Recommendation, 31 May 2001.
-(See <a href="http://www.w3.org/TR/2001/REC-ruby-20010531/">http://www.w3.org/TR/2001/REC-ruby-20010531/</a>.)
-</dd><dt class="label"><a id="smil3"></a>SMIL 3.0</dt><dd>Dick Bultermann, et al.,
-<a href="http://www.w3.org/TR/2008/REC-SMIL3-20081201/"><cite>Synchronized
-Multimedia Integration Language (SMIL 3.0)</cite></a>,
-W3C Recommendation, 1 December 2008. (See
-<a href="http://www.w3.org/TR/2008/REC-SMIL3-20081201/">http://www.w3.org/TR/2008/REC-SMIL3-20081201/</a>.)
-</dd><dt class="label"><a id="smpte12m"></a>SMPTE 12M</dt><dd>ANSI/SMPTE 12M,
-<a href="https://www.smpte.org/"><cite>Television, Audio and Film –
-Time and Control Code</cite></a>, SMPTE Standard.
-</dd><dt class="label"><a id="srgb"></a>SRGB</dt><dd>IEC 61966-2-1,
-<a href="http://www.iec.ch/"><cite>Multimedia
-systems and equipment – Colour measurement and management
-– Part 2-1: Colour management – Default RGB colour space
-– sRGB</cite></a>, International Electrotechnical
-Commission (IEC).
-</dd><dt class="label"><a id="svg11"></a>SVG 1.1</dt><dd>Erik Dahlström et al., Eds.,
-<a href="http://www.w3.org/TR/2011/REC-SVG11-20110816/"><cite>Scalable
-Vector Graphics (SVG) 1.1 Second Edition</cite></a>, W3C Recommendation, 16
-August 2011. (See
-<a href="http://www.w3.org/TR/2011/REC-SVG11-20110816/">http://www.w3.org/TR/2011/REC-SVG11-20110816/</a>.)
-</dd><dt class="label"><a id="uaag"></a>UAAG</dt><dd>Ian Jacobs, Jon Gunderson, and Eric Hansen, Eds.,
-<a href="http://www.w3.org/TR/2002/REC-UAAG10-20021217/"><cite>User
-Agent Accessibility Guidelines 1.0</cite></a>, W3C Recommendation, 17
-December 2002. (See
-<a href="http://www.w3.org/TR/2002/REC-UAAG10-20021217/">http://www.w3.org/TR/2002/REC-UAAG10-20021217/</a>.)
-</dd><dt class="label"><a id="uax14"></a>UAX14</dt><dd>Asmus Freytag, <a href="http://www.unicode.org/reports/tr14/tr14-17.html"><cite>Line Breaking
-Properties</cite></a>, Unicode Consortium, 29 August 2005. (See
-<a href="http://www.unicode.org/reports/tr14/tr14-17.html">http://www.unicode.org/reports/tr14/tr14-17.html</a>.)
-</dd><dt class="label"><a id="uri"></a>URI</dt><dd>T. Berner-Lee, R. Fielding, and L. Masinter,
-<a href="http://www.rfc-editor.org/rfc/rfc2396.txt"><cite>Uniform Resource Identifiers (URI): Generic Syntax</cite></a>,
-RFC 2396, August 1998, IETF.(See
-<a href="http://www.rfc-editor.org/rfc/rfc2396.txt">http://www.rfc-editor.org/rfc/rfc2396.txt</a>.)
-</dd><dt class="label"><a id="utc"></a>UTC</dt><dd>
-Recommendation TF.460,
-<a href="http://www.itu.int/"><cite>Standard-Frequency and Time-Signal
-Emissions</cite></a>, International
-Telecommunciations Union, Radio Sector (ITU-R).
-</dd><dt class="label"><a id="wcag"></a>WCAG</dt><dd>Ben Caldwell, et al., Eds.,
-<a href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/"><cite>Web
-Content Accessibility Guidelines (WCAG) 2.0</cite></a>, W3C Recommendation, 11 December 2008. (See
-<a href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/">http://www.w3.org/TR/2008/REC-WCAG20-20081211/</a>.)
-</dd><dt class="label"><a id="xlink11"></a>XLink 1.1</dt><dd>Steve DeRose, et al.
-<a href="http://www.w3.org/TR/2010/REC-xlink11-20100506/"><cite>XML Linking Language (XLink) Version 1.1</cite></a>,
-W3C Recommendation, 06 May 2010. (See
-<a href="http://www.w3.org/TR/2010/REC-xlink11-20100506/">http://www.w3.org/TR/2010/REC-xlink11-20100506/</a>.)
-</dd><dt class="label"><a id="xml10"></a>XML 1.0</dt><dd>Tim Bray, et al.
-<a href="http://www.w3.org/TR/2008/REC-xml-20081126/"><cite>Extensible Markup Language (XML)
-1.0 (Fifth Edition)</cite></a>, W3C Recommendation, 26 November 2008. (See
-<a href="http://www.w3.org/TR/2008/REC-xml-20081126/">http://www.w3.org/TR/2008/REC-xml-20081126/</a>.)
-</dd><dt class="label"><a id="xml11"></a>XML 1.1</dt><dd>Tim Bray, et al.
-<a href="http://www.w3.org/TR/2006/REC-xml11-20060816/"><cite>Extensible Markup Language (XML)
-1.1 (Second Edition)</cite></a>, W3C Recommendation, 16 August 2006, edited in place 29 September 2006. (See
-<a href="http://www.w3.org/TR/2006/REC-xml11-20060816/">http://www.w3.org/TR/2006/REC-xml11-20060816/</a>.)
-</dd><dt class="label"><a id="xmlbase"></a>XML Base</dt><dd>Jonathan Marsh and Richard Tobin, Eds.,
-<a href="http://www.w3.org/TR/2009/REC-xmlbase-20090128/"><cite>XML Base (Second Edition)</cite></a>,
-W3C Recommendation, 28 January 2009. (See
-<a href="http://www.w3.org/TR/2009/REC-xmlbase-20090128/">http://www.w3.org/TR/2009/REC-xmlbase-20090128/</a>.)
-</dd><dt class="label"><a id="xmlid"></a>XML ID</dt><dd>Jonathan Marsh, Daniel Veillard, Norman Walsh, Eds.,
-<a href="http://www.w3.org/TR/2005/REC-xml-id-20050909/"><cite>xml:id Version 1.0</cite></a>,
-W3C Recommendation, 09 September 2005. (See
-<a href="http://www.w3.org/TR/2005/REC-xml-id-20050909/">http://www.w3.org/TR/2005/REC-xml-id-20050909/</a>.)
-</dd><dt class="label"><a id="infoset"></a>XML InfoSet</dt><dd>John Cowan and Richard Tobin, Eds.,
-<a href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/"><cite>XML Information Set (Second Edition)</cite></a>,
-W3C Recommendation, 04 February 2004. (See
-<a href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/">http://www.w3.org/TR/2004/REC-xml-infoset-20040204/</a>.)
-</dd><dt class="label"><a id="xml-media"></a>XML Media Types</dt><dd>Makato Murata, Simon St. Laurent,
-Kan Khon, Eds., <a href="http://www.rfc-editor.org/rfc/rfc3023.txt"><cite>XML Media Types</cite></a>,
-RFC 3023, January 2001, IETF.(See
-<a href="http://www.rfc-editor.org/rfc/rfc3023.txt">http://www.rfc-editor.org/rfc/rfc3023.txt</a>.)
-</dd><dt class="label"><a id="xmlns10"></a>XML Namespaces 1.0</dt><dd>Tim Bray, et al.
-<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/"><cite>Namespaces
-in XML 1.0 (Third Edition)</cite></a>, W3C Recommendation, 8 December 2009. (See
-<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">http://www.w3.org/TR/2009/REC-xml-names-20091208/</a>.)
-</dd><dt class="label"><a id="xsd-1"></a>XML Schema Part 1</dt><dd>Henry S. Thompson, David Beech,
-Murray Maloney, Noah Mendelsohn, Eds.,
-<a href="http://www.w3.org/TR/xmlschema-1/"><cite>XML Schema Part 1: Structures</cite></a>,
-W3C Recommendation, 28 October 2004. (See
-<a href="http://www.w3.org/TR/xmlschema-1/">http://www.w3.org/TR/xmlschema-1/</a>.)
-</dd><dt class="label"><a id="xsd-2"></a>XML Schema Part 2</dt><dd>Paul Biron and Ashok Malhotra,
-<a href="http://www.w3.org/TR/xmlschema-2/"><cite>XML Schema Part 2: Datatypes</cite></a>,
-W3C Recommendation, 28 October 2004. (See
-<a href="http://www.w3.org/TR/xmlschema-2/">http://www.w3.org/TR/xmlschema-2/</a>.)
-</dd><dt class="label"><a id="xsl11"></a>XSL 1.1</dt><dd>Anders Berglund,
-<a href="http://www.w3.org/TR/2006/REC-xsl11-20061205/"><cite>Extensible Stylesheet Language (XSL) Version 1.1</cite></a>,
-W3C Recommendation, 05 December 2006. (See
-<a href="http://www.w3.org/TR/2006/REC-xsl11-20061205/">http://www.w3.org/TR/2006/REC-xsl11-20061205/</a>.)
-</dd></dl></div><div class="div1">
-<h2><a id="other-references"></a>K Other References (Non-Normative)</h2><dl><dt class="label"><a id="ccreq"></a>CC-DECODER-REQ</dt><dd><a href="http://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol4/pdf/CFR-2012-title47-vol4-sec79-101.pdf"><cite>Closed Caption Decoder
-Requirements for Analog Television Receivers</cite></a>,
-United States Code of Federal Regulations, Title 47, Volume 1, Part 79, § 79.101. (See
-<a href="http://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol4/pdf/CFR-2012-title47-vol4-sec79-101.pdf">http://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol4/pdf/CFR-2012-title47-vol4-sec79-101.pdf</a>.)
-</dd><dt class="label"><a id="cea608e"></a>CEA-608-E</dt><dd>
-EIA/CEA-608-E,
-<a href="http://www.ce.org/"><cite>Line 21 Data
-Services</cite></a>, EIA/CEA Standard,
-Consumer Electronics Association (CEA).
-</dd><dt class="label"><a id="cea708e"></a>CEA-708-E</dt><dd>
-CEA-708-D,
-<a href="http://www.ce.org/"><cite>Digital Television (DTV) Closed Captioning</cite></a>, CEA Standard,
-Consumer Electronics Association (CEA).
-</dd><dt class="label"><a id="css3-bb"></a>CSS Backgrounds and Borders</dt><dd>Bert Bos, Elika Etamad and Brad Kemper,
-<a href="http://dev.w3.org/csswg/css3-background/"><cite>CSS Backgrounds and Borders Module Level 3</cite></a>, W3C Editor's Draft. (See
-<a href="http://dev.w3.org/csswg/css3-background/">http://dev.w3.org/csswg/css-backgrounds/</a>.)
-</dd><dt class="label"><a id="css3-box"></a>CSS Box Model</dt><dd>Bert Bos, Anton Prowse,
-<a href="http://dev.w3.org/csswg/css-box-3/"><cite>CSS Basic Box Model</cite></a>, W3C Editor's Draft. (See
-<a href="http://dev.w3.org/csswg/css-box-3/">http://dev.w3.org/csswg/css-box-3/</a>.)
-</dd><dt class="label"><a id="css3-fonts"></a>CSS Fonts</dt><dd>John Daggett,
-<a href="http://dev.w3.org/csswg/css-fonts/"><cite>CSS Fonts Module Level 3</cite></a>, W3C Editor's Draft. (See
-<a href="http://dev.w3.org/csswg/css-fonts/">http://dev.w3.org/csswg/css-fonts/</a>.)
-</dd><dt class="label"><a id="css3-frag"></a>CSS Fragmentation</dt><dd>Rossen Atanassov and Elika Etemad,,
-<a href="http://dev.w3.org/csswg/css-break/"><cite>CSS Fragmentation Module Level 3</cite></a>, W3C Editor's Draft. (See
-<a href="http://dev.w3.org/csswg/css-break/">http://dev.w3.org/csswg/css-break/</a>.)
-</dd><dt class="label"><a id="cssruby"></a>CSS Ruby</dt><dd>Elika Etemad and Koji Ishii,
-<a href="http://dev.w3.org/csswg/css-ruby-1/"><cite>CSS Ruby Layout Module Level 1</cite></a>
-W3C Editor's Draft.
-(See <a href="http://dev.w3.org/csswg/css-ruby-1/">http://dev.w3.org/csswg/css-ruby-1/</a>.)
-</dd><dt class="label"><a id="css3-text"></a>CSS Text</dt><dd>Elika Etamad (aka fantasai) and Koji Ishii,
-<a href="http://dev.w3.org/csswg/css-text-3/"><cite>CSS Text Module Level 3</cite></a>, W3C Editor's Draft. (See
-<a href="http://dev.w3.org/csswg/css-text-3/">http://dev.w3.org/csswg/css-text-3/</a>.)
-</dd><dt class="label"><a id="css3-decoration"></a>CSS Text Decoration</dt><dd>Elika Etamad (aka fantasai) and Koji Ishii,
-<a href="http://dev.w3.org/csswg/css-text-decor-3/"><cite>CSS Text Decoration Module Level 3</cite></a>, W3C Editor's Draft. (See
-<a href="http://dev.w3.org/csswg/css-text-decor-3/">http://dev.w3.org/csswg/css-text-decor-3/</a>.)
-</dd><dt class="label"><a id="css3-wm"></a>CSS Writing Modes</dt><dd>Elika Etamad and Koji Ishii,
-<a href="http://dev.w3.org/csswg/css-writing-modes-3/"><cite>CSS Writing Modes Level 3</cite></a>, W3C Editor's Draft. (See
-<a href="http://dev.w3.org/csswg/css-writing-modes-3/">http://dev.w3.org/csswg/css-writing-modes-3/</a>.)
-</dd><dt class="label"><a id="dcmes"></a>DCMES 1.1</dt><dd>Dublin Core Metadata Initiative,
-<a href="http://dublincore.org/documents/dces/"><cite>Dublin Core Metadata Element Set, Version 1.1: Reference Description</cite></a>. (See
-<a href="http://dublincore.org/documents/dces/">http://dublincore.org/documents/dces/</a>.)
-</dd><dt class="label"><a id="jlreq"></a>JLREQ</dt><dd>Richard Ishida et al.,
-<a href="http://www.w3.org/TR/2012/NOTE-jlreq-20120403/"><cite>Requirements for Japanese Text Layout</cite></a>
-W3C Working Group Note, 3 April 2012.
-(See <a href="http://www.w3.org/TR/2012/NOTE-jlreq-20120403/">http://www.w3.org/TR/2012/NOTE-jlreq-20120403/</a>.)
-</dd><dt class="label"><a id="mpeg7-5"></a>MPEG7-5</dt><dd>
-ISO/IEC 15938-5,
-<a href="http://www.iso.org/"><cite>Information technology – Multimedia content description
-interface – Part 5: Multimedia description schemes</cite></a>,
-International Organization for Standardization (ISO).
-</dd><dt class="label"><a id="nsoriginal"></a>NSOriginal</dt><dd>Tim Bray, et al.
-<a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/"><cite>Namespaces
-in XML</cite></a>, W3C Recommendation, 14 January 1999. (See
-<a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/">http://www.w3.org/TR/1999/REC-xml-names-19990114/</a>.)
-</dd><dt class="label"><a id="nsstate"></a>NSState</dt><dd>Norman Walsh, Ed.,
-<a href="http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09.html"><cite>The Disposition
-of Names in an XML Namespace</cite></a>, TAG Finding, 9 January 2006. (See
-<a href="http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09.html">http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09</a>.)
-</dd><dt class="label"><a id="qaf-sg"></a>QAF SG</dt><dd>Karl Dubost, et al.,
-<a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/"><cite>QA
-Framework: Specifications Guidelines</cite></a>, W3C Recommendation, 17
-August 2005. (See
-<a href="http://www.w3.org/TR/qaframe-spec/">http://www.w3.org/TR/qaframe-spec/</a>.)
-</dd><dt class="label"><a id="sdpus"></a>SDP US</dt><dd>Glenn Adams, Monica Martin, Sean Hayes,
-<a href="http://www.w3.org/TR/2013/NOTE-ttml10-sdp-us-20130205/"><cite>TTML Simple Delivery Profile for Closed Captions (US)</cite></a>,
-W3C WG Note, 5 February 2013. (See
-<a href="http://www.w3.org/TR/2013/NOTE-ttml10-sdp-us-20130205/">http://www.w3.org/TR/2013/NOTE-ttml10-sdp-us-20130205/</a>.)
-</dd><dt class="label"><a id="smpte170m"></a>SMPTE 170M</dt><dd>ANSI/SMPTE 170M, 
-<a href="http://www.smpte.org/"><cite>Television – Composite Analog Video
-Signal – NTSC for Studio Applications</cite></a>, SMPTE Standard.
-</dd><dt class="label"><a id="smpte2052"></a>SMPTE 2052-11</dt><dd>SMPTE 2052-11,
-<a href="http://www.smpte.org/"><cite>Conversion from CEA-708 Caption Data to SMPTE-TT</cite></a>,
-SMPTE Recommended Practice.
-</dd><dt class="label"><a id="ttaf1-req"></a>TTAF1-REQ</dt><dd>Glenn Adams, Ed.,
-<a href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/"><cite>Timed Text (TT) Authoring Format 1.0 Use
-Cases and Requirements</cite></a>,
-W3C Working Group Note, 27 April 2006. (See
-<a href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/">http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/</a>.)
-</dd><dt class="label"><a id="ttml1"></a>TTML1</dt><dd>Glenn Adams, Ed.,
-<a href="http://www.w3.org/TR/2013/REC-ttml1-20130924/"><cite>Timed Text Markup Language 1 (TTML1) (Second Edition)</cite></a>,
-W3C Recommendation, 24 September 2013. (See
-<a href="http://www.w3.org/TR/2013/REC-ttml1-20130924/">http://www.w3.org/TR/2013/REC-ttml1-20130924/</a>.)
-</dd><dt class="label"><a id="xhtml10"></a>XHTML 1.0</dt><dd>Steven Pemberton, et al.,
-<a href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/"><cite>XHTML™ 1.0,
-The Extensible Hypertext Markup Language (Second Edition)</cite></a>,
-W3C Recommendation, 01
-August 2002. (See
-<a href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/">http://www.w3.org/TR/2002/REC-xhtml1-20020801/</a>.)
-</dd></dl></div><div class="div1">
-<h2><a id="requirements"></a>L Requirements (Non-Normative)</h2><p>The Timed Text Markup Language (TTML), also known as the Distribution Format Exchange Profile (DFXP) of the Timed Text Authoring
-Format (TTAF), satisfies a subset of the requirements established by
-<a href="#ttaf1-req">[TTAF1-REQ]</a>. The following table enumerates these requirements and
-indicates the extent to which they are satisfied by this specification, where
-<em>S</em> denotes a requirement is satisfied, <em>P</em> denotes
-a requirement is partially satisfied, and <em>N</em> denotes a
-requirement is not satisfied.</p><a id="requirements-table"></a><table class="common"><caption>Table L-1 – Requirement Satisfaction</caption><col width="10%" span="1"><col width="40%" span="1"><col width="10%" span="1"><col span="1"><tbody><tr><th>ID</th><th>Name</th><th>Status</th><th>Comments</th></tr><tr><td>R100</td><td>Specification Format</td><td>S</td><td></td></tr><tr><td>R101</td><td>Specification Modularity</td><td>S</td><td></td></tr><tr><td>R102</td><td>Specification Organization</td><td>S</td><td></td></tr><tr><td>R103</td><td>Core and Periphery</td><td>S</td><td>TT extension namespaces</td></tr><tr><td>R104</td><td>Evolution of Core</td><td>S</td><td>TT extension namespaces</td></tr><tr><td>R105</td><td>Ownership of Core</td><td>S</td><td>TT namespaces</td></tr><tr><td>R106</td><td>Surjection of Core</td><td>S</td><td></td></tr><tr><td>R107</td><td>Evolution of Periphery</td><td>S</td><td>TT extension namespaces</td></tr><tr><td>R108</td><td>Ownership of Periphery</td><td>S</td><td>Non-TT namespaces</td></tr><tr><td>R109</td><td>Transformation</td><td>S</td><td>Supports 3GPP, QText, RealText, SAMI</td></tr><tr><td>R110</td><td>Streamable Transformation</td><td>S</td><td>Progressive decoding</td></tr><tr><td>R111</td><td>Accessibility – Content</td><td>S</td><td>Alternative document instances</td></tr><tr><td>R112</td><td>Accessibility – Authoring System</td><td>S</td><td></td></tr><tr><td>R200</td><td>Authorability</td><td>S</td><td></td></tr><tr><td>R201</td><td>Multiple Natural Languages</td><td>S</td><td>Alternative document instances</td></tr><tr><td>R202</td><td>Natural Language Coverage</td><td>S</td><td>Unicode 4.0</td></tr><tr><td>R203</td><td>Natural Language Association Granularity</td><td>S</td><td>See <code>xml:lang</code></td></tr><tr><td>R204</td><td>Minimum Character Representability</td><td>S</td><td>Unicode 4.0</td></tr><tr><td>R205</td><td>Intrinsic and Extrinsic Text Content</td><td>P</td><td>Intrinsic only</td></tr><tr><td>R206</td><td>Markup Association</td><td>P</td><td>Intrinsic only</td></tr><tr><td>R207</td><td>Conditional Content</td><td>N</td><td></td></tr><tr><td>R208</td><td>Flowed Text</td><td>S</td><td></td></tr><tr><td>R209</td><td>Logical Flowed Text Vocabulary</td><td>S</td><td></td></tr><tr><td>R210</td><td>Presentational Flowed Text Vocabulary</td><td>S</td><td>Implied mapping from logical flowed text.</td></tr><tr><td>R211</td><td>Flowed Text Vocabulary Relationship</td><td>S</td><td></td></tr><tr><td>R212</td><td>Flowed Text Vocabulary Separation</td><td>N</td><td></td></tr><tr><td>R213</td><td>Non-Flowed Text</td><td>N</td><td></td></tr><tr><td>R214</td><td>Non-Flowed Text Vocabulary</td><td>N</td><td></td></tr><tr><td>R215</td><td>Hybrid Flowed and Non-Flowed Text</td><td>N</td><td></td></tr><tr><td>R216</td><td>Hyperlinking</td><td>N</td><td>Can support via XLink</td></tr><tr><td>R217</td><td>Embedded Graphics</td><td>N</td><td></td></tr><tr><td>R218</td><td>Non-Embedded Graphics</td><td>N</td><td></td></tr><tr><td>R219</td><td>Embedded Fonts</td><td>N</td><td></td></tr><tr><td>R220</td><td>Non-Embedded Fonts</td><td>N</td><td></td></tr><tr><td>R221</td><td>Descriptive Vocabulary</td><td>S</td><td>See <code>ttm:agent</code>, <code>ttm:role</code></td></tr><tr><td>R222</td><td>Embedded Audio</td><td>N</td><td></td></tr><tr><td>R223</td><td>Non-Embedded Audio</td><td>N</td><td></td></tr><tr><td>R290</td><td>Markup Format</td><td>S</td><td></td></tr><tr><td>R291</td><td>Markup Format and Unicode Interaction</td><td>S</td><td></td></tr><tr><td>R292</td><td>Extrinsic Resource References</td><td>N</td><td>No extrinsic references</td></tr><tr><td>R293</td><td>Schema Validity Specification</td><td>S</td><td></td></tr><tr><td>R300</td><td>Inline Styling</td><td>S</td><td></td></tr><tr><td>R301</td><td>Inline Styling Form</td><td>P</td><td>Inline and referential styling</td></tr><tr><td>R301</td><td>Out-of-Line Styling</td><td>N</td><td></td></tr><tr><td>R301</td><td>Out-of-Line Styling Form</td><td>N</td><td></td></tr><tr><td>R304</td><td>Styling Prioritization</td><td>S</td><td></td></tr><tr><td>R305</td><td>Style Parameters – Aural</td><td>N</td><td></td></tr><tr><td>R306</td><td>Style Parameters – Visual</td><td>P</td><td>Supports absolute position, background color, color, display none, display alignment,
-font family, font size, font style, font weight, height, line height, origin,
-opacity, overflow, padding (before, after, start, end), text alignment,
-text shadow (as outline), visibility, width, writing mode, z-index</td></tr><tr><td>R390</td><td>Style Parameter Symmetry</td><td>S</td><td></td></tr><tr><td>R391</td><td>Style Parameter Definitions</td><td>S</td><td></td></tr><tr><td>R392</td><td>Style Parameter Shorthands</td><td>S</td><td></td></tr><tr><td>R401</td><td>Inline Timing</td><td>S</td><td></td></tr><tr><td>R402</td><td>Out-of-Line Timing</td><td>N</td><td></td></tr><tr><td>R403</td><td>Synchronization Parameters</td><td>P</td><td>Supports begin, end, dur</td></tr><tr><td>R404</td><td>Synchronization Parameter Value Spaces</td><td>P</td><td>Supports offset values, media marker values (SMPTE 12M), wall-clock values</td></tr><tr><td>R405</td><td>Time Containment Semantics</td><td>P</td><td>Supports sequential, parallel</td></tr><tr><td>R500</td><td>Animation Modes</td><td>P</td><td>Supports discrete</td></tr><tr><td>R502</td><td>Highlight Animation</td><td>S</td><td><code>&lt;set tts:backgroundColor="..."/&gt;</code></td></tr><tr><td>R503</td><td>Fade Transition Animation</td><td>S</td><td><code>&lt;set tts:opacity="..."/&gt;</code></td></tr><tr><td>R504</td><td>Animated Style Parameters – Aural</td><td>N</td><td></td></tr><tr><td>R505</td><td>Animated Style Parameters – Visual</td><td>P</td><td>Supports animating background color, color, display, opacity, origin, visibility</td></tr><tr><td>N506</td><td>Animated Content</td><td>S</td><td></td></tr><tr><td>R600</td><td>Metadata Item Association</td><td>S</td><td>See <code>metadata</code>, <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a></td></tr><tr><td>R601</td><td>Metadata Item Constituents</td><td>P</td><td>Supports name, value</td></tr><tr><td>R602</td><td>Metadata Item Value Representation</td><td>P</td><td>See <code>metadata</code></td></tr><tr><td>R603</td><td>Metadata Item Extensibility</td><td>S</td><td>See <code>metadata</code></td></tr><tr><td>R604</td><td>Metadata Item Validation</td><td>S</td><td>See <code>metadata</code></td></tr><tr><td>R690</td><td>Dublin Core Preference</td><td>N</td><td>Uses <code>ttm:copyright</code>, <code>ttm:desc</code>, <code>ttm:title</code></td></tr></tbody></table></div><div class="div1">
-<h2><a id="derivation"></a>M Vocabulary Derivation (Non-Normative)</h2><p>This appendix provides information about the derivation of TTML
-vocabulary, separately describing derivation of elements and
-attributes.</p><table border="1" class="ednote" summary="Editorial note: Update Derivation"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Update Derivation</b></td><td align="right" valign="top">2015-01-14</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Update derivation tables to include new vocabulary added in TTML2.</td></tr></table><div class="div2">
-<h3><a id="d3e37582"></a>M.1 Element Derivation</h3><p>The first column of <a href="#element-vocab-derivation-table"><b>Table M-1 – Elements</b></a>
-specifies a TTML element vocabulary item; the second column specifies the
-syntactic and/or semantic model on which the vocabulary item is based;
-the third column specifies the reference that defines
-the model (if a model is indicated);
-the fourth column specifies details about the derivation; the last
-column refers to additional notes describing the nature of the
-derivation.</p><p>In the fourth column, which describes details of derivation, a
-notation is use to indicate the addition or removal of an attribute.
-For example, in the derivation of the <code>tt:div</code> element, the
-details column includes "-@class", which denotes that the
-<code>class</code> attribute that is specified for use with the
-<code>xhtml:div</code> model element is not specified for use with the
-corresponding TTML element; in contrast, the details column includes
-"+@begin", which denotes that a <code>begin</code> attribute is added
-that is not specified for use with the <code>xhtml:div</code> model
-element.</p><a id="element-vocab-derivation-table"></a><table class="common"><caption>Table M-1 – Elements</caption><col width="20%" span="1"><col width="17%" span="1"><col width="13%" align="center" span="1"><col width="40%" span="1"><col width="10%" align="center" span="1"><tbody><tr><td><span class="strong">Element</span></td><td><span class="strong">Model</span></td><td><span class="strong">Reference</span></td><td><span class="strong">Details</span></td><td><span class="strong">Notes</span></td></tr><tr><td><a href="#animation-vocabulary-animate"><code>tt:animate</code></a></td><td><code>svg:animate</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@* except begin, dur, end; +@tts:*, +@xml:lang, +@xml:space</td><td>3,6</td></tr><tr><td><a href="#animation-vocabulary-animation"><code>tt:animation</code></a></td><td><code>tt:layout</code></td><td><a href="#ttml1">[TTML1]</a></td><td>conceptual derivation</td><td>12</td></tr><tr><td><a href="#document-structure-vocabulary-body"><code>tt:body</code></a></td><td><code>xhtml:body</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
-+@timeContainer, +@ttm:*, +@tts:*; content model
-subsetted to zero or more division (div) children, and supersetted by
-optional metadata and animation children</td><td>1,2</td></tr><tr><td><a href="#content-vocabulary-br"><code>tt:br</code></a></td><td><code>xhtml:br</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@title; +@ttm:*, +@tts:*, +@xml:lang, +@xml:space;
-content model supersetted by
-optional metadata and animation children for congruity with other
-content vocabulary</td><td>1,2</td></tr><tr><td><a href="#content-vocabulary-div"><code>tt:div</code></a></td><td><code>xhtml:div</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
-+@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
-subsetted to zero or more paragraph (p) children, and supersetted by
-optional metadata and animation children</td><td>1,2,3</td></tr><tr><td><a href="#document-structure-vocabulary-head"><code>tt:head</code></a></td><td><code>xhtml:head</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@dir, -@lang, -@profile; +@id, +@xml:space; content model changed to
-optional metadata children, followed by optional styling child,
-followed by optional layout child</td><td>1,3</td></tr><tr><td><a href="#layout-vocabulary-layout"><code>tt:layout</code></a></td><td><code>fo:simple-page-master</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-metadata"><code>tt:metadata</code></a></td><td><code>svg:metadata</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@xml:base; +@ttm:*, +@xml:lang, +@xml:space; content model
-subsetted to foreign namespace element content only (no #PCDATA)</td><td>3,5</td></tr><tr><td><a href="#content-vocabulary-p"><code>tt:p</code></a></td><td><code>xhtml:p</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
-+@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
-subsetted to zero or more span children, and supersetted by optional
-metadata and animation children</td><td>1,2,3</td></tr><tr><td><a href="#layout-vocabulary-region"><code>tt:region</code></a></td><td><code>fo:region-*</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#animation-vocabulary-set"><code>tt:set</code></a></td><td><code>svg:set</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@* except begin, dur, end; +@tts:*, +@xml:lang, +@xml:space</td><td>3,6</td></tr><tr><td><a href="#content-vocabulary-span"><code>tt:span</code></a></td><td><code>xhtml:span</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
-+@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
-subsetted to zero or more #PCDATA or break (br) children, and
-supersetted by optional metadata and animation children</td><td>1,2,3</td></tr><tr><td><a href="#styling-vocabulary-style"><code>tt:style</code></a></td><td><em>style specification</em></td><td><a href="#css2">[CSS2]</a></td><td>XML representation of identified set of pairs of style property
-name and value, with optional inclusion of other styles by reference
-to other style elements</td><td>7</td></tr><tr><td><a href="#styling-vocabulary-styling"><code>tt:styling</code></a></td><td><code>xhtml:style</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>XML representation of a set of style specifications sets, each
-represented by a style child element</td><td>1,7</td></tr><tr><td><a href="#document-structure-vocabulary-tt"><code>tt:tt</code></a></td><td><code>xhtml:html</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@dir, -@lang; +@id, +@ttp:*, +@xml:space; content model subsetted by
-permitting body and/or head to be optional</td><td>1,8</td></tr><tr><td><a href="#metadata-vocabulary-actor"><code>ttm:actor</code></a></td><td><code>mpeg7:Creator</code></td><td><a href="#mpeg7-5">[MPEG7-5]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-agent"><code>ttm:agent</code></a></td><td><code>mpeg7:Agent</code></td><td><a href="#mpeg7-5">[MPEG7-5]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-copyright"><code>ttm:copyright</code></a></td><td><code>mpeg7:CopyrightString</code></td><td><a href="#mpeg7-5">[MPEG7-5]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-desc"><code>ttm:desc</code></a></td><td><code>svg:desc</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@class, -@style, -@xml:base</td><td>2,5,9</td></tr><tr><td><a href="#metadata-vocabulary-name"><code>ttm:name</code></a></td><td><code>mpeg7:Name</code></td><td><a href="#mpeg7-5">[MPEG7-5]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-title"><code>ttm:title</code></a></td><td><code>svg:title</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@class, -@style, -@xml:base</td><td>2,5,9</td></tr><tr><td><a href="#profile-vocabulary-extension"><code>ttp:extension</code></a></td><td><code>@requiredExtensions</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>10</td></tr><tr><td><a href="#profile-vocabulary-extensions"><code>ttp:extensions</code></a></td><td><code>@requiredExtensions</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>10</td></tr><tr><td><a href="#profile-vocabulary-feature"><code>ttp:feature</code></a></td><td><code>@requiredFeatures</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>10</td></tr><tr><td><a href="#profile-vocabulary-features"><code>ttp:features</code></a></td><td><code>@requiredFeatures</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>10</td></tr><tr><td><a href="#profile-vocabulary-profile"><code>ttp:profile</code></a></td><td><code>@baseProfile</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>11</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><ol class="enumar"><li><p>Derivation is indicated with respect to the strict DTD defined
-by <a href="#xhtml10">[XHTML 1.0]</a>, §A.1.</p></li><li><p>The <code>class</code> attribute is effectively replaced by the
-<code>style</code>
-attribute, which, instead of specifying an inline style,
-refers indirectly to one or more <a href="#styling-vocabulary-style"><code>style</code></a>
-elements that define a set of style specification sets.</p></li><li><p>The <code>xml:lang</code> and <code>xml:space</code> attributes are defined for all element
-types in order to support their inheritance semantics to operate in
-the context of foreign namespace elements.</p></li><li><p>Derivation is conceptual (notional) only.</p></li><li><p>The <code>xml:base</code> attribute is not used since there are no external
-references from core vocabulary.</p></li><li><p>The <code>attributeName</code> and <code>to</code> attributes of
-<code>svg:set</code> are replaced by the
-direct expression of the target attribute name and value by use of a
-<code>tts:*</code> attribute.</p></li><li><p>CSS style specification syntax is mapped to XML by use of
-attributes defined in the TT Style Namespace.</p></li><li><p>The <code>xml:id</code> attribute is defined for use on all element types.</p></li><li><p>The <code>style</code> attribute is supported only on
-<a href="#terms-content-element">content element</a>.</p></li><li><p>Derived from the use of <code>@requiredExtensions</code>
-and <code>@requiredFeatures</code> on the <code>svg:svg</code> element,
-but extended to support distinct specification of optionality.</p></li><li><p>Derived from the use of <code>@baseProfile</code>
-and <code>@version</code> on the <code>svg:svg</code> element.</p></li><li><p>Conceptually derived from existing <code>tt:layout</code> element,
-which is a generic container for layout specifications, but for use
-in defining animation specifications that apply to targeted elements.</p></li></ol></div></div><div class="div2">
-<h3><a id="d3e38099"></a>M.2 Attribute Derivation</h3><p>The first column of <a href="#attribute-vocab-derivation-table"><b>Table M-2 – Attributes</b></a>
-specifies a TTML attribute vocabulary item; the second column specifies the
-syntactic and/or semantic model on which the vocabulary item is based;
-the third column specifies the reference that defines
-the model (if a model is indicated);
-the fourth column specifies details about the derivation; the last
-column refers to additional notes describing the nature of the
-derivation.</p><p>In the fourth column, which describes details of derivation, a
-notation is use to indicate the addition or removal of an attribute
-value.  For example, in the derivation of the <code>timeContainer</code>
-attribute,
-the details column includes "-excl", which denotes that the
-<code>excl</code> value that is specified for use with the
-<code>timeContainer</code> model attribute is not specified for use with the
-corresponding TTML attribute; similarly, an "+<em>value</em>"
-in the details column indicates that the attribute's values have been
-extended to include <em>value</em>.</p><p>Only those attributes that are specified for use on more than one TTML
-element type are listed below. Those per-element namespace attributes
-that are uniquely defined for a specific TTML element type are not
-listed below, but are considered to be part of the specific element
-type's derivation described in <a href="#element-vocab-derivation-table"><b>Table M-1 – Elements</b></a>
-above.</p><a id="attribute-vocab-derivation-table"></a><table class="common"><caption>Table M-2 – Attributes</caption><col width="20%" span="1"><col width="17%" span="1"><col width="13%" align="center" span="1"><col width="40%" span="1"><col width="10%" align="center" span="1"><tbody><tr><td><span class="strong">Attribute</span></td><td><span class="strong">Model</span></td><td><span class="strong">Reference</span></td><td><span class="strong">Details</span></td><td><span class="strong">Notes</span></td></tr><tr><td><a href="#timing-attribute-begin"><code>begin</code></a></td><td><code>begin</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>see notes</td><td>2,3,4</td></tr><tr><td><a href="#timing-attribute-dur"><code>dur</code></a></td><td><code>dur</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>see notes</td><td>2,3,4</td></tr><tr><td><a href="#timing-attribute-end"><code>end</code></a></td><td><code>end</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>see notes</td><td>2,3,4</td></tr><tr><td><a href="#layout-attribute-region"><code>region</code></a></td><td><code>master-reference</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>conceptual derivation</td><td></td></tr><tr><td><a href="#style-attribute-style"><code>style</code></a></td><td><code>class</code></td><td><a href="#css2">[CSS2]</a></td><td>dereferences style specification(s) directly</td><td></td></tr><tr><td><a href="#timing-attribute-timeContainer"><code>timeContainer</code></a></td><td><code>timeContainer</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>
--<code>excl</code>,
--<code>none</code>;
-no default attribute value
-</td><td>5</td></tr><tr><td><a href="#metadata-attribute-agent"><code>ttm:agent</code></a></td><td><em>none</em></td><td></td><td>used to attribute agent of content</td><td></td></tr><tr><td><a href="#metadata-attribute-role"><code>ttm:role</code></a></td><td><em>none</em></td><td></td><td>used to attribute role of content</td><td></td></tr><tr><td><a href="#parameter-attribute-cellResolution"><code>ttp:cellResolution</code></a></td><td><em>none</em></td><td></td><td>expresses uniform grid resolution for cell based coordinates</td><td></td></tr><tr><td><a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a></td><td><em>none</em></td><td></td><td>determines how to interpret time expressions</td><td></td></tr><tr><td><a href="#parameter-attribute-frameRate"><code>ttp:frameRate</code></a></td><td><em>none</em></td><td></td><td>expresses integral frame rate</td><td></td></tr><tr><td><a href="#parameter-attribute-frameRateMultiplier"><code>ttp:frameRateMultiplier</code></a></td><td><em>none</em></td><td></td><td>used to express non-integral, rational frame rates</td><td></td></tr><tr><td><a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a></td><td><em>none</em></td><td></td><td>expresses marker continuity semantics</td><td></td></tr><tr><td><a href="#parameter-attribute-pixelAspectRatio"><code>ttp:pixelAspectRatio</code></a></td><td><em>none</em></td><td></td><td>expresses pixel aspect ratio of related media</td><td></td></tr><tr><td><a href="#profile-attribute-profile"><code>ttp:profile</code></a></td><td><em>none</em></td><td></td><td>expresses profile of TTML used by a <a href="#terms-document-instance">document instance</a></td><td></td></tr><tr><td><a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a></td><td><em>none</em></td><td></td><td>expresses frame counting (drop) modes</td><td></td></tr><tr><td><a href="#parameter-attribute-subFrameRate"><code>ttp:subFrameRate</code></a></td><td><em>none</em></td><td></td><td>expresses sub-frame rate</td><td></td></tr><tr><td><a href="#parameter-attribute-tickRate"><code>ttp:tickRate</code></a></td><td><em>none</em></td><td></td><td>used to interpret tick based time expressions</td><td></td></tr><tr><td><a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a></td><td><em>none</em></td><td></td><td>used to interpret semantics of time expressions</td><td></td></tr><tr><td><a href="#parameter-attribute-version"><code>ttp:version</code></a></td><td><code>version</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>used only integer values</td><td></td></tr><tr><td><a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a></td><td><code>background-color</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1,6</td></tr><tr><td><a href="#style-attribute-border"><code>tts:border</code></a></td><td><code>border</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1,6</td></tr><tr><td><a href="#style-attribute-color"><code>tts:color</code></a></td><td><code>color</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>6</td></tr><tr><td><a href="#style-attribute-direction"><code>tts:direction</code></a></td><td><code>direction</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td></td></tr><tr><td><a href="#style-attribute-display"><code>tts:display</code></a></td><td><code>display</code></td><td><a href="#css2">[CSS2]</a></td><td>only <code>auto</code>, <code>none</code></td><td></td></tr><tr><td><a href="#style-attribute-displayAlign"><code>tts:displayAlign</code></a></td><td><code>display-align</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#style-attribute-extent"><code>tts:extent</code></a></td><td><code>width</code>, <code>height</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>shorthand property</td><td></td></tr><tr><td><a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a></td><td><code>font-family</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, extends generic family names</td><td>1</td></tr><tr><td><a href="#style-attribute-fontSize"><code>tts:fontSize</code></a></td><td><code>font-size</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1,7</td></tr><tr><td><a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a></td><td><code>font-style</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>backslant</code></td><td>1</td></tr><tr><td><a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a></td><td><code>font-weight</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>bolder</code>, -<code>lighter</code>, -<code>&lt;number&gt;</code></td><td>1</td></tr><tr><td><a href="#style-attribute-lineHeight"><code>tts:lineHeight</code></a></td><td><code>line-height</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>&lt;number&gt;</code>, -<code>&lt;space&gt;</code></td><td>1</td></tr><tr><td><a href="#style-attribute-opacity"><code>tts:opacity</code></a></td><td><code>opacity</code></td><td><a href="#css3-color">[CSS3 Color]</a></td><td>-<code>inherit</code></td><td></td></tr><tr><td><a href="#style-attribute-origin"><code>tts:origin</code></a></td><td><code>top</code>, <code>left</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>shorthand property</td><td></td></tr><tr><td><a href="#style-attribute-overflow"><code>tts:overflow</code></a></td><td><code>overflow</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>auto</code>, -<code>error-if-overflow</code></td><td></td></tr><tr><td><a href="#style-attribute-padding"><code>tts:padding</code></a></td><td><code>padding</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>8</td></tr><tr><td><a href="#style-attribute-showBackground"><code>tts:showBackground</code></a></td><td><code>showBackground</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>-<code>inherit</code></td><td></td></tr><tr><td><a href="#style-attribute-textAlign"><code>tts:textAlign</code></a></td><td><code>text-align</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a></td><td><code>text-decoration</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1,9,12</td></tr><tr><td><a href="#style-attribute-textOrientation"><code>tts:textOrientation</code></a></td><td><code>text-orientation</code></td><td><a href="#css3-wm">[CSS Writing Modes]</a></td><td>
--<code>inherit</code>,
--<code>sideways-left</code>,
--<code>sideways-right</code>,
--<code>use-glyph-orientation</code>
-</td><td>1</td></tr><tr><td><a href="#style-attribute-textOutline"><code>tts:textOutline</code></a></td><td><code>text-shadow</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>10,12</td></tr><tr><td><a href="#style-attribute-unicodeBidi"><code>tts:unicodeBidi</code></a></td><td><code>unicode-bidi</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#style-attribute-visibility"><code>tts:visibility</code></a></td><td><code>visibility</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>collapse</code></td><td></td></tr><tr><td><a href="#style-attribute-wrapOption"><code>tts:wrapOption</code></a></td><td><code>wrap-option</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#style-attribute-writingMode"><code>tts:writingMode</code></a></td><td><code>writing-mode</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>
--<code>inherit</code>,
--<code>bt-lr</code>,
--<code>bt-rl</code>,
--<code>lr-bt</code>,
--<code>rl-bt</code>,
--<code>lr-alternating-rl-bt</code>,
--<code>lr-alternating-rl-tb</code>,
--<code>lr-inverting-rl-bt</code>,
--<code>lr-inverting-rl-tb</code>,
--<code>tb-lr-in-lr-pairs</code>
-</td><td>1</td></tr><tr><td><a href="#style-attribute-zIndex"><code>tts:zIndex</code></a></td><td><code>z-index</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#content-attribute-xml-id"><code>xml:id</code></a></td><td><code>xml:id</code></td><td><a href="#xmlid">[XML ID]</a></td><td>complies with model</td><td></td></tr><tr><td><a href="#content-attribute-xml-lang"><code>xml:lang</code></a></td><td><code>xml:lang</code></td><td><a href="#xml10">[XML 1.0]</a></td><td>complies with model</td><td></td></tr><tr><td><a href="#content-attribute-xml-space"><code>xml:space</code></a></td><td><code>xml:space</code></td><td><a href="#xml10">[XML 1.0]</a></td><td>see notes</td><td>11</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><ol class="enumar"><li><p>Attribute name and/or value(s) are normalized to use
-<em>lowerCamelCase</em> naming convention.</p></li><li><p>Restricted to expressing a clock value that denotes one of the
-following in accordance to whether the parameter expressed by the
-<code>ttp:timeBase</code> attribute is <code>media</code>, <code>smpte</code>,
-or <code>clock</code>, respectively:
-(1) an offset from an implicit syncbase that is linked to a media time
-line, (2) an event time
-that represents the occurrence of an implicit media marker, or (3) a wall-clock
-time.</p></li><li><p>Syntactically subsets and supersets the <a href="#smil3">[SMIL 3.0]</a>&nbsp;<code>Clock-value</code> syntax as follows:
-(1) requires non-negative <code>Full-clock-value</code> or
-<code>Timecount-value</code>;
-(2) if <code>Full-clock-value</code>
-then <em>hours</em> must be two or more digits;
-(3) if <code>Timecount-value</code>, then <em>metric</em> must be
-specified;
-(4) uses <code>m</code> as alias for <code>min</code> metric to denote
-minutes;
-(5) adds <code>f</code> and <code>t</code> metrics denoting frames and
-ticks, respectively;
-(6) adds alternative expression of optional <code>Fraction</code> in
-<code>Full-clock-value</code> by specifying frame count or frame
-count with subframe count.
-</p></li><li><p>
-Interpretation of time expression is further constrained by
-parameters expressed by
-<code>ttp:clockMode</code>,
-<code>ttp:dropMode</code>,
-<code>ttp:frameRate</code>,
-<code>ttp:frameRateMultiplier</code>,
-<code>ttp:markerMode</code>,
-<code>ttp:subFrameRate</code>,
-<code>ttp:tickRate</code>, and
-<code>ttp:timeBase</code> attributes.</p></li><li><p>Uses subset of named colors from model to which two aliases are
-added as follows: <code>magenta</code> as <code>fuchsia</code>, and <code>cyan</code>
-as <code>aqua</code>.</p></li><li><p>If not specified, then parallel (par) container semantics apply to
-the element types specified by <a href="#timing-attribute-timeContainer"><b>12.2.4 timeContainer</b></a>.</p></li><li><p>Restricts size to length specification which can be a percentage;
-adds optional second length (or percentage) for
-specifying separate horizontal and vertical scaling of glyph's EM
-square.</p></li><li><p>Expressed in terms of writing mode relative padding properties
-rather than absolute padding properties.</p></li><li><p>Excludes <code>blink</code> and <code>no-blink</code> values.</p></li><li><p>Uses only one length specification instead of two, where one length
-defines distance of outline effect from nominal edge of glyph contour
-outline perpendicular to point of glyph contour. Percentage lengths
-are also added to express outline effect in relative to font size.
-Outline effects are intended to be drawn both outside of outer closed
-contours and inside of inner closed contours.</p></li><li><p>On root element, default attribute value specified as
-<code>default</code>, which is defined in terms of whitespace
-normalization. Semantics of preservation and default normalization are
-defined in terms of presentation semantics by <a href="#content-attribute-xml-space"><b>8.2.9 xml:space</b></a>.</p></li><li><p>Defined to be inheritable.</p></li></ol></div></div></div><div class="div1">
-<h2><a id="qa"></a>N QA Framework Compliance (Non-Normative)</h2><p>This appendix specifies the compliance of this specification with the
-requirements and guidelines defined by <a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/">QA
-Framework Specifications Guidelines</a>&nbsp;<a href="#qaf-sg">[QAF SG]</a>.</p><div class="div2">
-<h3><a id="d3e39092"></a>N.1 Requirements</h3><a id="qa-framework-requirements-table"></a><table class="common"><caption>Table N-1 – QA Framework Requirements Checklist</caption><col width="76%" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><tbody><tr><td><span class="strong">Requirement</span></td><td><span class="strong">YES</span></td><td><span class="strong">NO</span></td><td><span class="strong">N/A</span></td><td><span class="strong">Notes</span></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#include-conformance-clause-principle">Requirement 01: Include a conformance
-clause</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-scope-principle">Requirement 02: Define the scope.</a></td><td><a href="#intro">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#implement-principle">Requirement 03: Identify who or what will implement the specification.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ref-norm-principle">Requirement 04: Make a list of normative references.</a></td><td><a href="#references">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-terms-principle">Requirement 05: Define the terms used in the normative parts of the specification.</a></td><td><a href="#definitions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conf-label-principle">Requirement 06: Create conformance labels for each part of the conformance model.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#consistent-style-principle">Requirement 07: Use a consistent style for conformance requirements and explain how to distinguish them.</a></td><td><a href="#conventions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#req-opt-conf-principle">Requirement 08: Indicate which conformance requirements are mandatory, which are recommended, and which are optional.</a></td><td><a href="#conventions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdivide-mandatory-principle">Requirement 09: If the technology is subdivided, then indicate which subdivisions are mandatory for conformance.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdiv-constraints-principle">Requirement 10: If the technology is subdivided, then address subdivision constraints.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#likehood-extension-principle">Requirement 11: Address Extensibility.</a></td><td><a href="#doctypes">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#deprecated-feature-principle">Requirement 12: Identify deprecated features.</a></td><td></td><td></td><td>N/A</td><td>1</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#degree-support-principle">Requirement 13: Define how each class of product handles each deprecated feature.</a></td><td></td><td></td><td>N/A</td><td>1</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><ol class="enumar"><li><p>No feature is deprecated by this version of this specification.</p></li></ol></div></div><div class="div2">
-<h3><a id="d3e39256"></a>N.2 Guidelines</h3><a id="qa-framework-guidelines-table"></a><table class="common"><caption>Table N-2 – QA Framework Guidelines Checklist</caption><col width="76%" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><tbody><tr><td><span class="strong">Guideline</span></td><td><span class="strong">YES</span></td><td><span class="strong">NO</span></td><td><span class="strong">N/A</span></td><td><span class="strong">Notes</span></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conformance-model-gp">Good Practice 01: Define the specification's conformance model in the conformance clause.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#norm-informative-gp">Good Practice 02: Specify in the conformance clause how to distinguish normative from informative content.</a></td><td><a href="#conventions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conformance-claim-gp">Good Practice 03: Provide the wording for conformance claims.</a></td><td><a href="#claims">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ics-gp">Good Practice 04: Provide an Implementation Conformance Statement Pro Forma.</a></td><td></td><td>NO</td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ics-claim-gp">Good Practice 05: Require an Implementation Conformance Statement as part of valid conformance claims.</a></td><td><a href="#claims">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#use-example-gp">Good Practice 06: Provide examples, use cases, and graphics.</a></td><td><a href="#example">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#write-sample-gp">Good Practice 07: Write sample code or tests.</a></td><td>YES</td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ref-define-practice">Good Practice 08: When imposing requirements by normative references, address conformance dependencies.</a></td><td><a href="#references">YES</a></td><td></td><td></td><td>1</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-terms-inline-gp">Good Practice 09: Define unfamiliar terms in-line and consolidate the definitions in a glossary section.</a></td><td><a href="#definitions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#reuse-terms-gp">Good Practice 10: Use terms already defined without changing their definition.</a></td><td><a href="#definitions">YES</a></td><td></td><td></td><td>2</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#formal-language-gp">Good Practice 11: Use formal languages when possible.</a></td><td><a href="#schemas">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#write-assertion-gp">Good Practice 12: Write Test Assertions.</a></td><td></td><td>NO</td><td></td><td>3</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdivide-foster-gp">Good Practice 13: Create subdivisions of the technology when warranted.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#rules-profiles-gp">Good Practice 14: If the technology is profiled, define rules for creating new profiles.</a></td><td><a href="#vocabulary-profiling">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#need-option-gp">Good Practice 15:Use optional features as warranted.</a></td><td>YES</td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#label-options-gp">Good Practice 16: Clearly identify optional features.</a></td><td>YES</td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#constraints-gp">Good Practice 17: Indicate any limitations or constraints on optional features.</a></td><td>YES</td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#extensions-prohibited-gp">Good Practice 18: If extensibility is allowed, define an extension mechanism.</a></td><td><a href="#extension-vocabulary-overview">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#breaking-conformance-gp">Good Practice 19: Warn extension creators to create extensions that do not interfere with conformance.</a></td><td><a href="#extension-vocabulary-overview">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-error-gp">Good Practice 20: Define error-handling for unknown extensions.</a></td><td><a href="#conformance-processor">YES</a></td><td></td><td></td><td>4</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#workaround-gp">Good Practice 21: Explain how to avoid using a deprecated feature.</a></td><td></td><td></td><td>N/A</td><td>5</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#obsolete-gp">Good Practice 22: Identify obsolete features.</a></td><td></td><td></td><td>N/A</td><td>5</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#error-handling-gp">Good Practice 23: Define an error handling mechanism.</a></td><td><a href="#reduced-infoset">YES</a></td><td></td><td></td><td></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><ol class="enumar"><li><p>When making normative references to external specifications,
-specific clauses or sections are cited.</p></li><li><p>See also <a href="#derivation"><b>M Vocabulary Derivation</b></a>.</p></li><li><p>Test assertions and test suites will be provided prior to entering
-Proposed Recommendation (PR) phase.</p></li><li><p>See criterion #3 in <a href="#conformance-processor"><b>3.2 Processor Conformance</b></a> and definition of
-TTML <a href="#doctypes">Abstract Document Instance</a>.</p></li><li><p>No feature is deprecated or obsoleted by this version of this specification.</p></li></ol></div></div></div><div class="div1">
-<h2><a id="streaming"></a>O Streaming TTML Content (Non-Normative)</h2><p>TTML Content is designed to support streamability by implementing the
-following properties:</p><ul><li><p>can be progressively encoded (i.e., does not require computing
-subsequent data prior to sending current data);</p></li><li><p>can be progressively decoded (i.e., does not require forward
-references, but uses only reverse references when necessary);</p></li><li><p>does not require dereferencing (and subsequent loading) of any
-resources other than TTML Content (i.e., no embedded URIs);</p></li><li><p>does not support alternative content forms (e.g., different
-language, graphics formats, time bases) in a single document;</p></li><li><p>has timing structure compiled into inline format that makes
-possible a temporal ordering of content that follows temporal
-presentation order;</p></li><li><p>constrains content models to prevent arbitrary nested content
-structures;</p></li></ul><p>One possible means by which TTML Content may be streamed is to
-partition a <a href="#terms-document-instance">document instance</a>'s information set into
-non-overlapping fragments, where one particular fragment, call it the
-<em>root fragment</em>, represents the front matter (head) of the
-<a href="#terms-document-instance">document instance</a> as well as its top level structural elements, and
-other fragments represent content whose time intervals are expected to
-be active in parallel.</p><p>In applications that require arbitrary (random) entry into a
-stream, i.e., the property of being able to start reading data at an
-arbitrary data access unit, the root fragment will be repetitively
-transmitted (inserted) into the stream in order to permit a decoder to
-resynchronize and acquire sufficient structural information in the
-information set in order to interpret subsequent content
-fragments.</p><p>An example of such a fragmentation of a <a href="#terms-document-instance">document instance</a> is
-shown in <a href="#fragment-streaming-graphic"><b>Figure 3 – Fragment Streaming</b></a>.</p><a id="fragment-streaming-graphic"></a><table class="example-images"><caption>Figure 3 – Fragment Streaming</caption><col span="1"><tbody><tr><td><img src="images/streaming.png" alt="Fragment Streaming"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not define a transport buffer model or a decoder
-capabilities model.</p></div></div><div class="div1">
-<h2><a id="common-styling"></a>P Common Caption Style Examples (Non-Normative)</h2><p>This section provides examples of the following common caption styles using TTML Content
-to obtain the desired behavior:</p><ul><li><p>Pop-On Captions</p></li><li><p>Roll-Up Captions</p></li><li><p>Paint-On Captions</p></li></ul><div class="div2">
-<h3><a id="pop-on-example"></a>P.1 Pop-On Caption Example</h3><p>An example of paint-on captions. In this example, two regions are targeted with alternating, paint-on content, where content is timed
-using explicit sequential time containment rules. Each paragraph is non-overlapping in time and appears in the same single row
-of its targeted region.</p><a id="pop-on-example-1-s"></a><table class="example"><caption>Example – Pop-On Captions</caption><tbody><tr><td>
-<div class="exampleInner"><pre>&lt;tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;head&gt;
-    &lt;layout&gt;
-      &lt;region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 1c"/&gt;
-      &lt;region xml:id="r2" tts:color="yellow" tts:origin="10c 8c" tts:extent="40c 1c"/&gt;
-    &lt;/layout&gt;
-  &lt;/head&gt;
-  &lt;body&gt;
-    &lt;div timeContainer="seq"&gt;
-      &lt;p region="r1" dur="4s"&gt;Lorem ipsum dolor sit&lt;/p
-      &lt;p region="r2" dur="4s"&gt;Amet consectetur adipiscing elit&lt;/p&gt;
-      &lt;p region="r1" dur="6s"&gt;Sed do eiusmod tempor incididunt labore&lt;/p&gt;
-      &lt;p region="r2" dur="4s"&gt;et dolore magna aliqua&lt;/p&gt;
-      &lt;p region="r1" dur="7s"&gt;Ut enim ad minim veniam quis, nostrud&lt;/p&gt;
-    &lt;/div&gt;
-  &lt;/body&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table></div><div class="div2">
-<h3><a id="roll-up-example"></a>P.2 Roll-Up Caption Example</h3><p>An example of roll-up captions. Roll-up effects are achieved by using overlapped time intervals, where zero, one, or two paragraphs appear in the region
-at a given time. Each paragraph consumes a single row (line) of the region since no wrapping occurs. Depending on whether a <a href="#terms-presentation-processor">presentation processor</a> supports
-<a href="#semantics-smooth-scrolling-recommendation">smooth scrolling between adjacent synchronic intermediate document instances</a>, the transitions, i.e., moving an
-old paragraph (line) out and a new paragraph (line) in, will be either smooth or discrete.</p><a id="roll-up-example-1-s"></a><table class="example"><caption>Example – Roll-Up Captions</caption><tbody><tr><td>
-<div class="exampleInner"><pre>&lt;tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;head&gt;
-    &lt;layout&gt;
-      &lt;region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 2c"/&gt;
-    &lt;/layout&gt;
-  &lt;/head&gt;
-  &lt;body&gt;
-    &lt;div region="r1"&gt;
-      &lt;p begin="0s" end="8s"&gt;Lorem ipsum dolor sit&lt;/p
-      &lt;p begin="4s" end="12s"&gt;Amet consectetur adipiscing elit&lt;/p&gt;
-      &lt;p begin="8s" end="18s"&gt;Sed do eiusmod tempor incididunt labore&lt;/p&gt;
-      &lt;p begin="14s" end="25s"&gt;et dolore magna aliqua&lt;/p&gt;
-      &lt;p begin="18s" end="29s"&gt;Ut enim ad minim veniam quis, nostrud&lt;/p&gt;
-    &lt;/div&gt;
-  &lt;/body&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table></div><div class="div2">
-<h3><a id="paint-on-example"></a>P.3 Paint-On Caption Example</h3><p>An example of paint-on captions. Paint-on effects are achieved by using timed <code>span</code> elements in order to expose (paint) inline text units, e.g., words,
-over some time interval. Here, five paragraphs have their individual words sequentially timed in order to paint one new word every second. The end of the active duration of
-each inline element coincides with the end of the <code>div</code> element's parallel time container, so that once a word is painted, it remains in the region (on its rendered line) until the <code>div</code> element's active time interval lapses.</p><a id="paint-on-example-1-s"></a><table class="example"><caption>Example – Paint-On Captions</caption><tbody><tr><td>
-<div class="exampleInner"><pre>&lt;tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
-  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
-  &lt;head&gt;
-    &lt;layout&gt;
-      &lt;region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 5c"/&gt;
-    &lt;/layout&gt;
-  &lt;/head&gt;
-  &lt;body&gt;
-    &lt;div begin="0s" end="25s"&gt;
-      &lt;p&gt;
-        &lt;span begin="0s"&gt;Lorem&lt;/span&gt;
-        &lt;span begin="1s"&gt;ipsum&lt;/span&gt;
-        &lt;span begin="2s"&gt;dolor&lt;/span&gt;
-        &lt;span begin="3s"&gt;sit&lt;/span&gt;
-      &lt;/p&gt;
-      &lt;p&gt;
-        &lt;span begin="4s"&gt;Amet&lt;/span&gt;                
-        &lt;span begin="5s"&gt;consectetur&lt;/span&gt;
-        &lt;span begin="6s"&gt;adipiscing&lt;/span&gt;
-        &lt;span begin="7s"&gt;elit&lt;/span&gt;
-      &lt;/p&gt;
-      &lt;p&gt;
-        &lt;span begin="8s"&gt;Sed&lt;/span&gt;
-        &lt;span begin="9s"&gt;do&lt;/span&gt;
-        &lt;span begin="10s"&gt;eiusmod&lt;/span&gt;
-        &lt;span begin="11s"&gt;tempor&lt;/span&gt;
-        &lt;span begin="12s"&gt;incididunt &lt;/span&gt;
-        &lt;span begin="13s"&gt;labore&lt;/span&gt;
-     &lt;/p&gt;
-     &lt;p&gt;
-        &lt;span begin="14s"&gt;et&lt;/span&gt;
-        &lt;span begin="15s"&gt;dolore&lt;/span&gt;
-        &lt;span begin="16s"&gt;magna&lt;/span&gt;
-        &lt;span begin="17s"&gt;aliqua&lt;/span&gt;
-      &lt;/p&gt;
-      &lt;p&gt;
-        &lt;span begin="18s"&gt;Ut&lt;/span&gt;
-        &lt;span begin="19s"&gt;enim&lt;/span&gt;
-        &lt;span begin="20s"&gt;ad&lt;/span&gt;
-        &lt;span begin="21s"&gt;minim&lt;/span&gt;
-        &lt;span begin="22s"&gt;veniam&lt;/span&gt;
-        &lt;span begin="23s"&gt;quis,&lt;/span&gt;
-        &lt;span begin="24s"&gt;nostrud&lt;/span&gt;
-      &lt;/p&gt;
-    &lt;/div&gt;
-  &lt;/body&gt;
-&lt;/tt&gt;
-</pre></div>
-</td></tr></tbody></table></div></div><div class="div1">
-<h2><a id="cea708-mapping"></a>Q CEA708 Mapping Considerations (Non-Normative)</h2><p>This section provides additional information about mapping CEA708
-constructs to TTML.</p><table border="1" class="ednote" summary="Editorial note: CEA708 Mapping"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: CEA708 Mapping</b></td><td align="right" valign="top">2014-03-06</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Refer to ST2052-11 as starting point. Add additional considerations.</td></tr></table></div><div class="div1">
-<h2><a id="acknowledgments"></a>R Acknowledgments (Non-Normative)</h2><p>The editor acknowledges the current and former members of the Timed Text Working
-Group, the members of other W3C Working Groups, and industry experts
-in other forums who have contributed directly or indirectly to the
-process or content of this document as follows:</p><p>Glenn Adams,
-Thomas Bause-Mason,
-John Birch,
-Kees Blom,
-Bert Bos,
-Brad Botkin,
-Dick Bulterman,
-Frans de Jong,
-Mike Dolan,
-Martin Dürst,
-Donald Evans,
-Geoff Freed,
-Al Gilman,
-Giles Godart-Brown,
-Markus Gylling,
-Markku Hakkinen,
-Sean Hayes,
-Erik Hodge,
-Philipp Hoschka,
-Suzi Hyun,
-Michael Jordan,
-Masahiko Kaneko,
-Courtney Kennedy,
-George Kerscher,
-David Kirby,
-Andrew Kirkpatrick,
-Philippe Le Hégaret,
-Pierre-Anthony Lemieux,
-Chris Lilley,
-Jason Livingston,
-Monica Martin,
-Matthew May,
-Nigel Megitt,
-Thierry Michel,
-Frank Olivier,
-Soohong Daniel Park,
-Silvia Pfeiffer,
-Rohit Puri,
-Brian Raymor,
-David Ronca,
-Patrick Schmitz,
-David Singer,
-Craig Smithpeters,
-Andreas Tai,
-and Mohamed Zergaoui.
-</p><p>The editor wishes to especially acknowledge the following contributions
-by current and past members: Mike Dolan (SMPTE time codes, streaming; SMPTE liaison), David
-Kirby (introductory example document; SMPTE time codes, descriptive metadata; EBU/AAF liaison), Geoff Freed (styling
-and example images of style properties), Sean Hayes (advanced profile
-concepts, including applicative timing, HTML/CSS mapping proposal), Erik Hodge (timing),
-Thierry Michel (metadata), and Dave Singer (animation, scrolling).</p><p>The editor also wishes to acknowledge the support of the following current and past sponsors of his work
-on this specification: Cox Communications, Netflix, Microsoft, and Samsung Electronics.</p><p>The Working Group dedicates this specification to our colleague David Kirby.</p></div></div></body></html>
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml2/spec/ttml2-20150114-pre-fpwd-review-1.html	Wed Jan 14 09:53:09 2015 -0700
@@ -0,0 +1,10430 @@
+<!DOCTYPE html
+  PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html lang="en-us"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>Timed Text Markup Language 2 (TTML2) -- (Editor's copy)</title><style type="text/css">
+code           { font-family: monospace; }
+
+div.constraint,
+div.issue,
+div.note,
+div.notice     { margin-left: 2em; }
+
+ol.enumar      { list-style-type: decimal; }
+ol.enumla      { list-style-type: lower-alpha; }
+ol.enumlr      { list-style-type: lower-roman; }
+ol.enumua      { list-style-type: upper-alpha; }
+ol.enumur      { list-style-type: upper-roman; }
+
+
+div.exampleInner pre { margin-left: 1em;
+                       margin-top: 0em; margin-bottom: 0em}
+div.exampleOuter {border: 4px double gray;
+                  margin: 0em; padding: 0em}
+div.exampleInner { background-color: #d5dee3;
+                   border-top-width: 4px;
+                   border-top-style: double;
+                   border-top-color: #d3d3d3;
+                   border-bottom-width: 4px;
+                   border-bottom-style: double;
+                   border-bottom-color: #d3d3d3;
+                   padding: 4px; margin: 0em }
+div.exampleWrapper { margin: 4px }
+div.exampleHeader { font-weight: bold;
+                    margin: 4px}
+
+li p { margin-top: 0.3em; margin-bottom: 0.3em; }
+div.issue { border: 2px solid black; background-color: #ffff66; padding: 0em 1em; margin: 0em 0em }
+table.ednote { border-collapse: collapse; border: 2px solid black; width: 85% }
+table.ednote td { background-color: #ddaa66; border: 2px solid black }
+table.acronyms td.label { width: 15% }
+table.acronyms td.def { width: 65% }
+table.graphic { border: 0px none black; width: 100%; border-collapse: collapse }
+table.graphic caption { font-weight: bold; text-align: center; padding-bottom: 0.5em }
+table.graphic td { border: 0px none black; text-align: center }
+table.common { border: 2px solid black; width: 85%; border-collapse: collapse }
+table.common caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+table.common th { padding: 0em 0.5em; border: 2px solid black; text-align: left }
+table.common td { padding: 0em 0.5em; border: 2px solid black }
+table.syntax { border: 0px solid black; width: 85%; border-collapse: collapse }
+table.syntax caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+table.syntax th { border: 0px solid black; text-align: left }
+table.syntax td { border: 0px solid black }
+table.syntax div { background-color: #ffffc8 }
+table.semantics { border: 0px solid black; width: 85%; border-collapse: collapse }
+table.semantics caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+table.semantics th { border: 0px solid black; text-align: left }
+table.semantics td {
+  border-left: 0px solid black;
+  border-right: 0px solid black;
+  border-top: 4px double #d3d3d3;
+  border-bottom: 4px double #d3d3d3;
+  background-color: #ccffcc
+}
+table.semantics code.formulae {
+  padding: 1em;
+  border: 1px dashed #005a9c;
+  line-height: 1.1em;
+  background-color: #fdfdfd;
+}
+table.example { border: 0px solid black; width: 85%; border-collapse: collapse }
+table.example caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+table.example th { border: 0px solid black; text-align: left }
+table.example td { border: 0px solid black;  }
+table.example div { background-color: #c8ffff }
+table.example-images { text-align: center; border: 0px solid black; width: 85%; border-collapse: collapse }
+table.example-images caption { font-weight: bold; text-align: center; padding-bottom: 0.5em }
+table.example-images td { border: 0px solid black; text-align: center }
+table.example-images-bordered { text-align: center; border: 0px solid black; width: 85%; border-collapse: collapse }
+table.example-images-bordered caption { font-weight: bold; text-align: center; padding-bottom: 0.5em }
+table.example-images-bordered td { border: 1px solid red; text-align: left }
+div.exampleInner { width: 85%; }
+.tbd { background-color: #ffff33; border: 2px solid black; width: 85% }
+.strong { font-weight: bold }
+.deprecated { background-color: #fbaf5c }
+.obsoleted { background-color: #f26d7d }
+.reqattr { font-weight: bold }
+.optattr { font-style: italic }
+</style><link rel="stylesheet" type="text/css" href="https://www.w3.org/StyleSheets/TR/W3C-ED.css"></head><body>Last Modified: $Date: 2015/01/14 16:45:15 $<div id="revisions"></div><div class="head">
+<h1><a id="title"></a>Timed Text Markup Language 2 (TTML2)</h1>
+<h2><a id="w3c-doctype"></a>Editors' copy $Date: 2015/01/14 16:45:15 $ @@ @@@@ @@@@</h2><dl><dt>This version:</dt><dd>
+<a href="ttml2.html">ttml2.html</a>
+</dd><dt>Latest version:</dt><dd><a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml2/spec/ttml2.html?content-type=text/html;charset=utf-8">https://dvcs.w3.org/hg/ttml/raw-file/default/ttml2/spec/ttml2.html?content-type=text/html;charset=utf-8</a></dd><dt>Previous version:</dt><dd>
+<a href="http://www.w3.org/TR/2013/REC-ttml1-20130924/">http://www.w3.org/TR/2013/REC-ttml1-20130924/</a>
+</dd><dt>Editor:</dt><dd>Glenn Adams, Skynav, Inc.</dd><dt>Contributing Authors:</dt><dd>Mike Dolan, Invited Expert</dd><dd>Sean Hayes, Microsoft</dd><dd>Frans de Jong, European Broadcasting Union</dd><dd>Pierre-Anthony Lemieux, MovieLabs</dd><dd>Nigel Megitt, British Broadcasting Corporation</dd><dd>Dave Singer, Apple Computer</dd><dd>Jerry Smith, Microsoft</dd><dd>Andreas Tai, Invited Expert</dd></dl><p>Please refer to the <a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml10/spec/ttml-issues.html">errata</a> for this document, which may
+      include normative corrections.</p><p>See also <a href="http://www.w3.org/2003/03/Translations/byTechnology?technology=ttml2"><strong>translations</strong></a>.</p><p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>&nbsp;©&nbsp;@@@@&nbsp;<a href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>, <a href="http://ev.buaa.edu.cn/">Beihang</a>), All Rights Reserved. W3C <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p></div><hr><div>
+<h2><a id="abstract"></a>Abstract</h2><p>This document specifies the Timed Text Markup Language (TTML), Version 2, also known as TTML2,
+in terms of a vocabulary and semantics thereof.</p><p>The Timed Text Markup Language is a content type that represents
+timed text media for the purpose of interchange among authoring
+systems. Timed text is textual information that is intrinsically or
+extrinsically associated with timing information.</p><p>It is intended to be used
+for the purpose of transcoding or exchanging timed text information
+among legacy distribution content formats presently in use for
+subtitling and captioning functions.</p><p>In addition to being used for interchange among legacy distribution content
+formats, TTML Content may be used directly as a distribution format,
+for example, providing a standard content format to reference from a <code>&lt;track&gt;</code>
+element in an HTML5 document, or a <code>&lt;text&gt;</code> or 
+<code>&lt;textstream&gt;</code> media element in a <a href="#smil3">[SMIL 3.0]</a> document.</p></div><div>
+<h2><a id="status"></a>Status of this Document</h2><p><strong>This document is an editor's copy that has
+        no official standing.</strong></p><p></p></div><div class="toc">
+<h2><a id="contents"></a>Table of Contents</h2><p class="toc">1 <a href="#intro">Introduction</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;1.1 <a href="#model">System Model</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;1.2 <a href="#example">Document Example</a><br>
+2 <a href="#definitions">Definitions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;2.1 <a href="#acronyms">Acronyms</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;2.2 <a href="#terms">Terminology</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;2.3 <a href="#conventions">Documentation Conventions</a><br>
+3 <a href="#conformance">Conformance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;3.1 <a href="#conformance-content">Document Conformance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;3.2 <a href="#conformance-processor">Processor Conformance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.2.1 <a href="#conformance-generic-processor">Generic Processor Conformance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.2.2 <a href="#conformance-transformation-processor">Transformation Processor Conformance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.2.3 <a href="#conformance-presentation-processor">Presentation Processor Conformance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;3.3 <a href="#claims">Claims</a><br>
+4 <a href="#doctypes">Document Types</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;4.1 <a href="#ttml-content-doctype">TTML Content Document Type</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;4.2 <a href="#ttml-intermediate-doctype">TTML Intermediate Document Type</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;4.3 <a href="#ttml-profile-doctype">TTML Profile Document Type</a><br>
+5 <a href="#vocabulary">Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;5.1 <a href="#vocabulary-namespaces">Namespaces</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;5.2 <a href="#vocabulary-profiling">Profiling</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.1 <a href="#vocabulary-profile-introduction">Introduction</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.2 <a href="#semantics-profile-examples">Profile Examples</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.3 <a href="#vocabulary-profile-designators">Profile Designators</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.3.1 <a href="#vocabulary-profile-standard-designators">Standard Designators</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.4 <a href="#semantics-profile-semantics">Profile Semantics</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.4.1 <a href="#semantics-profile-state">Profile State Object Concepts</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.4.2 <a href="#semantics-content-profile-processing">Content Profile Semantics</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.2.4.3 <a href="#semantics-processor-profile-processing">Processor Profile Semantics</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;5.3 <a href="#vocabulary-overview">Catalog</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.3.1 <a href="#core-vocabulary-overview">Core Catalog</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.3.2 <a href="#extension-vocabulary-overview">Extension Catalog</a><br>
+6 <a href="#profile">Profile</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;6.1 <a href="#profile-element-vocabulary">Profile Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.1 <a href="#profile-vocabulary-profile">ttp:profile</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.2 <a href="#profile-vocabulary-features">ttp:features</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.3 <a href="#profile-vocabulary-feature">ttp:feature</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.4 <a href="#profile-vocabulary-extensions">ttp:extensions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.5 <a href="#profile-vocabulary-extension">ttp:extension</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;6.2 <a href="#profile-attribute-vocabulary">Profile Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.1 <a href="#profile-attribute-contentProfiles">ttp:contentProfiles</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.2 <a href="#profile-attribute-contentProfileCombination">ttp:contentProfileCombination</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.3 <a href="#profile-attribute-inferProcessorProfileMethod">ttp:inferProcessorProfileMethod</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.4 <a href="#profile-attribute-inferProcessorProfileSource">ttp:inferProcessorProfileSource</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.5 <a href="#profile-attribute-permitFeatureNarrowing">ttp:permitFeatureNarrowing</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.6 <a href="#profile-attribute-permitFeatureWidening">ttp:permitFeatureWidening</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.7 <a href="#profile-attribute-profile">ttp:profile</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.8 <a href="#profile-attribute-processorProfiles">ttp:processorProfiles</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.9 <a href="#profile-attribute-processorProfileCombination">ttp:processorProfileCombination</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.10 <a href="#profile-attribute-validation">ttp:validation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.11 <a href="#profile-attribute-validationAction">ttp:validationAction</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.12 <a href="#profile-attribute-version">ttp:version</a><br>
+7 <a href="#parameter">Parameter</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;7.1 <a href="#parameter-element-vocabulary">Parameter Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;7.2 <a href="#parameter-attribute-vocabulary">Parameter Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.1 <a href="#parameter-attribute-cellResolution">ttp:cellResolution</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.2 <a href="#parameter-attribute-clockMode">ttp:clockMode</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.3 <a href="#parameter-attribute-dropMode">ttp:dropMode</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.4 <a href="#parameter-attribute-frameRate">ttp:frameRate</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.5 <a href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultiplier</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.6 <a href="#parameter-attribute-markerMode">ttp:markerMode</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.7 <a href="#parameter-attribute-mediaDuration">ttp:mediaDuration</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.8 <a href="#parameter-attribute-mediaOffset">ttp:mediaOffset</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.9 <a href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.10 <a href="#parameter-attribute-storageAspectRatio">ttp:storageAspectRatio</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.11 <a href="#parameter-attribute-subFrameRate">ttp:subFrameRate</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.12 <a href="#parameter-attribute-tickRate">ttp:tickRate</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.13 <a href="#parameter-attribute-timeBase">ttp:timeBase</a><br>
+8 <a href="#content">Content</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;8.1 <a href="#content-element-vocabulary">Content Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.1 <a href="#document-structure-vocabulary-tt">tt</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.2 <a href="#document-structure-vocabulary-head">head</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.3 <a href="#document-structure-vocabulary-body">body</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.4 <a href="#content-vocabulary-div">div</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.5 <a href="#content-vocabulary-p">p</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.6 <a href="#content-vocabulary-span">span</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.7 <a href="#content-vocabulary-br">br</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;8.2 <a href="#content-attribute-vocabulary">Content Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.1 <a href="#content-attribute-condition">condition</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.2 <a href="#content-attribute-xlink-arcrole">xlink:arcrole</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.3 <a href="#content-attribute-xlink-href">xlink:href</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.4 <a href="#content-attribute-xlink-role">xlink:role</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.5 <a href="#content-attribute-xlink-show">xlink:show</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.6 <a href="#content-attribute-xlink-title">xlink:title</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.7 <a href="#content-attribute-xml-id">xml:id</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.8 <a href="#content-attribute-xml-lang">xml:lang</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.9 <a href="#content-attribute-xml-space">xml:space</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;8.3 <a href="#content-value-expressions">Content Value Expressions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.1 <a href="#content-value-arguments">&lt;arguments&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.2 <a href="#content-value-bound-parameter">&lt;bound-parameter&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.3 <a href="#content-value-condition">&lt;condition&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.4 <a href="#content-value-condition-function">&lt;condition-function&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.5 <a href="#content-value-expression">&lt;expression&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.6 <a href="#content-value-media-function">&lt;media-function&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.7 <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.8 <a href="#content-value-parameter-function">&lt;parameter-function&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.9 <a href="#content-value-supports-function">&lt;supports-function&gt;</a><br>
+9 <a href="#embedded-content">Embedded Content</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;9.1 <a href="#embedded-content-element-vocabulary">Embedded Content Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.1 <a href="#embedded-content-vocabulary-audio">audio</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.2 <a href="#embedded-content-vocabulary-chunk">chunk</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.3 <a href="#embedded-content-vocabulary-data">data</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.4 <a href="#embedded-content-vocabulary-font">font</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.5 <a href="#embedded-content-vocabulary-image">image</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.6 <a href="#embedded-content-vocabulary-resources">resources</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.7 <a href="#embedded-content-vocabulary-source">source</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;9.2 <a href="#embedded-content-attribute-vocabulary">Embedded Content Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.1 <a href="#embedded-content-attribute-encoding">encoding</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.2 <a href="#embedded-content-attribute-format">format</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.3 <a href="#embedded-content-attribute-src">src</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.4 <a href="#embedded-content-attribute-type">type</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;9.3 <a href="#embedded-content-value-expressions">Embedded Content Value Expressions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.1 <a href="#embedded-content-value-audio">&lt;audio&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.2 <a href="#embedded-content-value-audio-format">&lt;audio-format&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.3 <a href="#embedded-content-value-data">&lt;data&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.4 <a href="#embedded-content-value-data-format">&lt;data-format&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.5 <a href="#embedded-content-value-font">&lt;font&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.6 <a href="#embedded-content-value-font-format">&lt;font-format&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.7 <a href="#embedded-content-value-image">&lt;image&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.8 <a href="#embedded-content-value-image-format">&lt;image-format&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.9 <a href="#embedded-content-value-unicode-range">&lt;unicode-range&gt;</a><br>
+10 <a href="#styling">Styling</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;10.1 <a href="#styling-element-vocabulary">Styling Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.1.1 <a href="#styling-vocabulary-initial">initial</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.1.2 <a href="#styling-vocabulary-style">style</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.1.3 <a href="#styling-vocabulary-styling">styling</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;10.2 <a href="#styling-attribute-vocabulary">Styling Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.1 <a href="#style-attribute-style">style</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.2 <a href="#style-attribute-backgroundColor">tts:backgroundColor</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.3 <a href="#style-attribute-backgroundImage">tts:backgroundImage</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.4 <a href="#style-attribute-backgroundPosition">tts:backgroundPosition</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.5 <a href="#style-attribute-backgroundRepeat">tts:backgroundRepeat</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.6 <a href="#style-attribute-border">tts:border</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.7 <a href="#style-attribute-color">tts:color</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.8 <a href="#style-attribute-direction">tts:direction</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.9 <a href="#style-attribute-display">tts:display</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.10 <a href="#style-attribute-displayAlign">tts:displayAlign</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.11 <a href="#style-attribute-extent">tts:extent</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.12 <a href="#style-attribute-fontFamily">tts:fontFamily</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.13 <a href="#style-attribute-fontKerning">tts:fontKerning</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.14 <a href="#style-attribute-fontSelectionStrategy">tts:fontSelectionStrategy</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.15 <a href="#style-attribute-fontShear">tts:fontShear</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.16 <a href="#style-attribute-fontSize">tts:fontSize</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.17 <a href="#style-attribute-fontStyle">tts:fontStyle</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.18 <a href="#style-attribute-fontVariantPosition">tts:fontVariantPosition</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.19 <a href="#style-attribute-fontWeight">tts:fontWeight</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.20 <a href="#style-attribute-height">tts:height</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.21 <a href="#style-attribute-letterSpacing">tts:letterSpacing</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.22 <a href="#style-attribute-lineHeight">tts:lineHeight</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.23 <a href="#style-attribute-opacity">tts:opacity</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.24 <a href="#style-attribute-origin">tts:origin</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.25 <a href="#style-attribute-overflow">tts:overflow</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.26 <a href="#style-attribute-padding">tts:padding</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.27 <a href="#style-attribute-position">tts:position</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.28 <a href="#style-attribute-ruby">tts:ruby</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.29 <a href="#style-attribute-rubyAlign">tts:rubyAlign</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.30 <a href="#style-attribute-rubyOffset">tts:rubyOffset</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.31 <a href="#style-attribute-rubyPosition">tts:rubyPosition</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.32 <a href="#style-attribute-showBackground">tts:showBackground</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.33 <a href="#style-attribute-textAlign">tts:textAlign</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.34 <a href="#style-attribute-textCombine">tts:textCombine</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.35 <a href="#style-attribute-textDecoration">tts:textDecoration</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.36 <a href="#style-attribute-textEmphasis">tts:textEmphasis</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.37 <a href="#style-attribute-textOrientation">tts:textOrientation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.38 <a href="#style-attribute-textOutline">tts:textOutline</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.39 <a href="#style-attribute-textShadow">tts:textShadow</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.40 <a href="#style-attribute-unicodeBidi">tts:unicodeBidi</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.41 <a href="#style-attribute-visibility">tts:visibility</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.42 <a href="#style-attribute-width">tts:width</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.43 <a href="#style-attribute-wrapOption">tts:wrapOption</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.44 <a href="#style-attribute-writingMode">tts:writingMode</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.45 <a href="#style-attribute-zIndex">tts:zIndex</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;10.3 <a href="#styling-style-value-expressions">Styling Value Expressions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.1 <a href="#style-value-alpha">&lt;alpha&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.2 <a href="#style-value-borderColor">&lt;borderColor&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.3 <a href="#style-value-borderStyle">&lt;borderStyle&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.4 <a href="#style-value-borderWidth">&lt;borderWidth&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.5 <a href="#style-value-color">&lt;color&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.6 <a href="#style-value-digit">&lt;digit&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.7 <a href="#style-value-emphasisColor">&lt;emphasisColor&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.8 <a href="#style-value-emphasisStyle">&lt;emphasisStyle&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.9 <a href="#style-value-emphasisPosition">&lt;emphasisPosition&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.10 <a href="#style-value-familyName">&lt;familyName&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.11 <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.12 <a href="#style-value-hexDigit">&lt;hexDigit&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.13 <a href="#style-value-integer">&lt;integer&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.14 <a href="#style-value-length">&lt;length&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.15 <a href="#style-value-measure">&lt;measure&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.16 <a href="#style-value-namedColor">&lt;namedColor&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.17 <a href="#style-value-non-negative-integer">&lt;non-negative-integer&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.18 <a href="#style-value-number">&lt;number&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.19 <a href="#style-value-percentage">&lt;percentage&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.20 <a href="#style-value-position">&lt;position&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.21 <a href="#style-value-shadow">&lt;shadow&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;10.4 <a href="#semantics-styling">Styling Semantics</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1 <a href="#semantics-style-association">Style Association</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1.1 <a href="#semantics-style-association-inline">Inline Styling</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1.2 <a href="#semantics-style-association-referential">Referential Styling</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1.3 <a href="#semantics-style-association-chained-referential">Chained Referential Styling</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.1.4 <a href="#semantics-style-association-nested">Nested Styling</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.2 <a href="#semantics-style-inheritance">Style Inheritance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.2.1 <a href="#semantics-style-inheritance-content">Content Style Inheritance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.2.2 <a href="#semantics-style-inheritance-region">Region Style Inheritance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.2.3 <a href="#semantics-style-inheritance-root">Root Style Inheritance</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.3 <a href="#semantics-style-resolution-value-categories">Style Resolution Value Categories</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.3.1 <a href="#semantics-style-resolved-value-category-specified">Specified Values</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.3.2 <a href="#semantics-style-resolved-value-category-computed">Computed Values</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.3.3 <a href="#semantics-style-resolved-value-category-actual">Actual Values</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4 <a href="#semantics-style-resolution-processing">Style Resolution Processing</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4.1 <a href="#semantics-style-resolution-processing-definitions">Conceptual Definitions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4.2 <a href="#semantics-style-resolution-processing-sss">Specified Style Set Processing</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4.3 <a href="#semantics-style-resolution-processing-css">Computed Style Set Processing</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.4.4 <a href="#semantics-style-resolution-process-overall">Style Resolution Process</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.4.5 <a href="#semantics-style-automatic-measure-calculation">Automatic Measure Calculation</a><br>
+11 <a href="#layout">Layout</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;11.1 <a href="#layout-element-vocabulary">Layout Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.1.1 <a href="#layout-vocabulary-layout">layout</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.1.2 <a href="#layout-vocabulary-region">region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;11.2 <a href="#layout-attribute-vocabulary">Layout Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.2.1 <a href="#layout-attribute-region">region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;11.3 <a href="#semantics-layout">Layout Semantics</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1 <a href="#semantics-region-layout">Region Layout and Presentation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.1 <a href="#semantics-default-region">Default Region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.2 <a href="#semantics-inline-regions">Inline Regions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.3 <a href="#semantics-region-layout-step-1">Intermediate Synchronic Document Construction</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.4 <a href="#semantics-region-layout-step-2">Synchronic Flow Processing</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.1.5 <a href="#semantics-region-layout-example">Elaborated Example (Non-Normative)</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.3.2 <a href="#semantics-line-layout">Line Layout</a><br>
+12 <a href="#timing">Timing</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;12.1 <a href="#timing-element-vocabulary">Timing Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;12.2 <a href="#timing-attribute-vocabulary">Timing Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.1 <a href="#timing-attribute-begin">begin</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.2 <a href="#timing-attribute-dur">dur</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.3 <a href="#timing-attribute-end">end</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.4 <a href="#timing-attribute-timeContainer">timeContainer</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;12.3 <a href="#timing-time-value-expressions">Time Value Expressions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.3.1 <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;12.4 <a href="#semantics-timing">Timing Semantics</a><br>
+13 <a href="#animation">Animation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;13.1 <a href="#animation-element-vocabulary">Animation Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.1.1 <a href="#animation-vocabulary-animate">animate</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.1.2 <a href="#animation-vocabulary-animation">animation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.1.3 <a href="#animation-vocabulary-set">set</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;13.2 <a href="#animation-attribute-vocabulary">Animation Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.2.1 <a href="#animation-attribute-animate">animate</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;13.3 <a href="#animation-value-expressions">Animation Value Expressions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.1 <a href="#animation-value-animationValue">&lt;animationValue&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.2 <a href="#animation-value-animationValueList">&lt;animationValueList&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.3 <a href="#animation-value-calcMode">&lt;calcMode&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.4 <a href="#animation-value-fill">&lt;fill&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.5 <a href="#animation-value-keySplines">&lt;keySplines&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.6 <a href="#animation-value-keyTimes">&lt;keyTimes&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.3.7 <a href="#animation-value-repeatCount">&lt;repeatCount&gt;</a><br>
+14 <a href="#metadata">Metadata</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;14.1 <a href="#metadata-element-vocabulary">Metadata Element Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.1 <a href="#metadata-vocabulary-metadata">metadata</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.2 <a href="#metadata-vocabulary-actor">ttm:actor</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.3 <a href="#metadata-vocabulary-agent">ttm:agent</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.4 <a href="#metadata-vocabulary-copyright">ttm:copyright</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.5 <a href="#metadata-vocabulary-desc">ttm:desc</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.6 <a href="#metadata-vocabulary-item">ttm:item</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.7 <a href="#metadata-vocabulary-name">ttm:name</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.1.8 <a href="#metadata-vocabulary-title">ttm:title</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;14.2 <a href="#metadata-attribute-vocabulary">Metadata Attribute Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.2.1 <a href="#metadata-attribute-agent">ttm:agent</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.2.2 <a href="#metadata-attribute-role">ttm:role</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;14.3 <a href="#metadata-value-expressions">Metadata Value Expressions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.3.1 <a href="#metadata-value-item-name">&lt;item-name&gt;</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.3.2 <a href="#metadata-value-named-item">&lt;named-item&gt;</a><br>
+</p>
+<h3><a id="appendices"></a>Appendices</h3><p class="toc">A <a href="#concrete-encoding">Concrete Encoding</a><br>
+B <a href="#reduced-infoset">Reduced XML Infoset</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;B.1 <a href="#reduced-infoset-document">Document Information Item</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;B.2 <a href="#reduced-infoset-element">Element Information Item</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;B.3 <a href="#reduced-infoset-attribute">Attribute Information Item</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;B.4 <a href="#reduced-infoset-character">Character Information Item</a><br>
+C <a href="#schemas">Schemas</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;C.1 <a href="#ttml-schema-rnc">Relax NG Compact (RNC) Schema</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;C.2 <a href="#ttml-schema-xsd">XML Schema Definition (XSD) Schema</a><br>
+D <a href="#media-types-registration">Media Type Registration</a><br>
+E <a href="#features">Features</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;E.1 <a href="#feature-designations">Feature Designations</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.1 <a href="#feature-animation">#animation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.2 <a href="#feature-backgroundColor">#backgroundColor</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.3 <a href="#feature-backgroundColor-block">#backgroundColor-block</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.4 <a href="#feature-backgroundColor-inline">#backgroundColor-inline</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.5 <a href="#feature-backgroundColor-region">#backgroundColor-region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.6 <a href="#feature-bidi">#bidi</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.7 <a href="#feature-border">#border</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.8 <a href="#feature-cellResolution">#cellResolution</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.9 <a href="#feature-clockMode">#clockMode</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.10 <a href="#feature-clockMode-gps">#clockMode-gps</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.11 <a href="#feature-clockMode-local">#clockMode-local</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.12 <a href="#feature-clockMode-utc">#clockMode-utc</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.13 <a href="#feature-color">#color</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.14 <a href="#feature-content">#content</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.15 <a href="#feature-core">#core</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.16 <a href="#feature-direction">#direction</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.17 <a href="#feature-display">#display</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.18 <a href="#feature-display-block">#display-block</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.19 <a href="#feature-display-inline">#display-inline</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.20 <a href="#feature-display-region">#display-region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.21 <a href="#feature-displayAlign">#displayAlign</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.22 <a href="#feature-dropMode">#dropMode</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.23 <a href="#feature-dropMode-dropNTSC">#dropMode-dropNTSC</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.24 <a href="#feature-dropMode-dropPAL">#dropMode-dropPAL</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.25 <a href="#feature-dropMode-nonDrop">#dropMode-nonDrop</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.26 <a href="#feature-extent">#extent</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.27 <a href="#feature-extent-region">#extent-region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.28 <a href="#feature-extent-root">#extent-root</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.29 <a href="#feature-fontFamily">#fontFamily</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.30 <a href="#feature-fontFamily-generic">#fontFamily-generic</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.31 <a href="#feature-fontFamily-non-generic">#fontFamily-non-generic</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.32 <a href="#feature-fontSize">#fontSize</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.33 <a href="#feature-fontSize-anamorphic">#fontSize-anamorphic</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.34 <a href="#feature-fontSize-isomorphic">#fontSize-isomorphic</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.35 <a href="#feature-fontStyle">#fontStyle</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.36 <a href="#feature-fontStyle-italic">#fontStyle-italic</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.37 <a href="#feature-fontStyle-oblique">#fontStyle-oblique</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.38 <a href="#feature-fontWeight">#fontWeight</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.39 <a href="#feature-fontWeight-bold">#fontWeight-bold</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.40 <a href="#feature-frameRate">#frameRate</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.41 <a href="#feature-frameRateMultiplier">#frameRateMultiplier</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.42 <a href="#feature-layout">#layout</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.43 <a href="#feature-length">#length</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.44 <a href="#feature-length-cell">#length-cell</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.45 <a href="#feature-length-em">#length-em</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.46 <a href="#feature-length-integer">#length-integer</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.47 <a href="#feature-length-negative">#length-negative</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.48 <a href="#feature-length-percentage">#length-percentage</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.49 <a href="#feature-length-pixel">#length-pixel</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.50 <a href="#feature-length-positive">#length-positive</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.51 <a href="#feature-length-real">#length-real</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.52 <a href="#feature-lineBreak-uax14">#lineBreak-uax14</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.53 <a href="#feature-lineHeight">#lineHeight</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.54 <a href="#feature-markerMode">#markerMode</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.55 <a href="#feature-markerMode-continuous">#markerMode-continuous</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.56 <a href="#feature-markerMode-discontinuous">#markerMode-discontinuous</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.57 <a href="#feature-metadata">#metadata</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.58 <a href="#feature-nested-div">#nested-div</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.59 <a href="#feature-nested-span">#nested-span</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.60 <a href="#feature-opacity">#opacity</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.61 <a href="#feature-origin">#origin</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.62 <a href="#feature-overflow">#overflow</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.63 <a href="#feature-overflow-visible">#overflow-visible</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.64 <a href="#feature-padding">#padding</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.65 <a href="#feature-padding-1">#padding-1</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.66 <a href="#feature-padding-2">#padding-2</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.67 <a href="#feature-padding-3">#padding-3</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.68 <a href="#feature-padding-4">#padding-4</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.69 <a href="#feature-pixelAspectRatio">#pixelAspectRatio</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.70 <a href="#feature-presentation">#presentation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.71 <a href="#feature-profile">#profile</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.72 <a href="#feature-showBackground">#showBackground</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.73 <a href="#feature-structure">#structure</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.74 <a href="#feature-styling">#styling</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.75 <a href="#feature-styling-chained">#styling-chained</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.76 <a href="#feature-styling-inheritance-content">#styling-inheritance-content</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.77 <a href="#feature-styling-inheritance-region">#styling-inheritance-region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.78 <a href="#feature-styling-inline">#styling-inline</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.79 <a href="#feature-styling-nested">#styling-nested</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.80 <a href="#feature-styling-referential">#styling-referential</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.81 <a href="#feature-subFrameRate">#subFrameRate</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.82 <a href="#feature-textAlign">#textAlign</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.83 <a href="#feature-textAlign-absolute">#textAlign-absolute</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.84 <a href="#feature-textAlign-relative">#textAlign-relative</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.85 <a href="#feature-textDecoration">#textDecoration</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.86 <a href="#feature-textDecoration-over">#textDecoration-over</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.87 <a href="#feature-textDecoration-through">#textDecoration-through</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.88 <a href="#feature-textDecoration-under">#textDecoration-under</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.89 <a href="#feature-textOrientation">#textOrientation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.90 <a href="#feature-textOutline">#textOutline</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.91 <a href="#feature-textOutline-blurred">#textOutline-blurred</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.92 <a href="#feature-textOutline-unblurred">#textOutline-unblurred</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.93 <a href="#feature-tickRate">#tickRate</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.94 <a href="#feature-timeBase-clock">#timeBase-clock</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.95 <a href="#feature-timeBase-media">#timeBase-media</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.96 <a href="#feature-timeBase-smpte">#timeBase-smpte</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.97 <a href="#feature-timeContainer">#timeContainer</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.98 <a href="#feature-time-clock">#time-clock</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.99 <a href="#feature-time-clock-with-frames">#time-clock-with-frames</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.100 <a href="#feature-time-offset">#time-offset</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.101 <a href="#feature-time-offset-with-frames">#time-offset-with-frames</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.102 <a href="#feature-time-offset-with-ticks">#time-offset-with-ticks</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.103 <a href="#feature-timing">#timing</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.104 <a href="#feature-transformation">#transformation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.105 <a href="#feature-unicodeBidi">#unicodeBidi</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.106 <a href="#feature-version">#version</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.107 <a href="#feature-visibility">#visibility</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.108 <a href="#feature-visibility-block">#visibility-block</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.109 <a href="#feature-visibility-inline">#visibility-inline</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.110 <a href="#feature-visibility-region">#visibility-region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.111 <a href="#feature-wrapOption">#wrapOption</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.112 <a href="#feature-writingMode">#writingMode</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.113 <a href="#feature-writingMode-vertical">#writingMode-vertical</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.114 <a href="#feature-writingMode-horizontal">#writingMode-horizontal</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.115 <a href="#feature-writingMode-horizontal-lr">#writingMode-horizontal-lr</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.116 <a href="#feature-writingMode-horizontal-rl">#writingMode-horizontal-rl</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.1.117 <a href="#feature-zIndex">#zIndex</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;E.2 <a href="#feature-support">Feature Support</a><br>
+F <a href="#extensions">Extensions</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;F.1 <a href="#extension-designations">Extension Designations</a><br>
+G <a href="#standard-profiles">Standard Profiles</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;G.1 <a href="#profile-ttml2-full">TTML2 Full Profile</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;G.2 <a href="#profile-ttml2-presentation">TTML2 Presentation Profile</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;G.3 <a href="#profile-ttml2-transformation">TTML2 Transformation Profile</a><br>
+H <a href="#time-expression-semantics">Time Expression Semantics</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;H.1 <a href="#time-expression-semantics-clock">Clock Time Base</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;H.2 <a href="#time-expression-semantics-media">Media Time Base</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;H.3 <a href="#time-expression-semantics-smpte">SMPTE Time Base</a><br>
+I <a href="#isd">Intermediate Document Syntax</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;I.1 <a href="#isd-vocabulary">ISD Vocabulary</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I.1.1 <a href="#isd-vocabulary-sequence">isd:sequence</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I.1.2 <a href="#isd-vocabulary-isd">isd:isd</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I.1.3 <a href="#isd-vocabulary-css">isd:css</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I.1.4 <a href="#isd-vocabulary-region">isd:region</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;I.2 <a href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;I.3 <a href="#isd-interchange">ISD Interchange</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;I.4 <a href="#isd-examples">ISD Examples</a><br>
+J <a href="#references">References</a><br>
+K <a href="#other-references">Other References</a> (Non-Normative)<br>
+L <a href="#requirements">Requirements</a> (Non-Normative)<br>
+M <a href="#derivation">Vocabulary Derivation</a> (Non-Normative)<br>
+&nbsp;&nbsp;&nbsp;&nbsp;M.1 <a href="#d3e37582">Element Derivation</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;M.2 <a href="#d3e38099">Attribute Derivation</a><br>
+N <a href="#qa">QA Framework Compliance</a> (Non-Normative)<br>
+&nbsp;&nbsp;&nbsp;&nbsp;N.1 <a href="#d3e39092">Requirements</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;N.2 <a href="#d3e39256">Guidelines</a><br>
+O <a href="#streaming">Streaming TTML Content</a> (Non-Normative)<br>
+P <a href="#common-styling">Common Caption Style Examples</a> (Non-Normative)<br>
+&nbsp;&nbsp;&nbsp;&nbsp;P.1 <a href="#pop-on-example">Pop-On Caption Example</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;P.2 <a href="#roll-up-example">Roll-Up Caption Example</a><br>
+&nbsp;&nbsp;&nbsp;&nbsp;P.3 <a href="#paint-on-example">Paint-On Caption Example</a><br>
+Q <a href="#cea708-mapping">CEA708 Mapping Considerations</a> (Non-Normative)<br>
+R <a href="#acknowledgments">Acknowledgments</a> (Non-Normative)<br>
+</p></div><hr><div class="body"><div class="div1">
+<h2><a id="intro"></a>1 Introduction</h2><p><em>Unless specified otherwise, this section and its sub-sections are non-normative.</em></p><p>The Timed Text Markup Language (TTML), Version 2, also referred to as TTML2,
+provides a standardized representation of a particular subset of
+textual information with which stylistic, layout, and timing semantics are associated by
+an author or an authoring system for the purpose of interchange and processing.</p><p>TTML is expressly designed to meet only a limited set of requirements
+established by <a href="#ttaf1-req">[TTAF1-REQ]</a>, and summarized in <a href="#requirements"><b>L Requirements</b></a>. In particular, only those requirements which service the
+need of performing interchange with existing, legacy distribution systems are
+satisfied.</p><p>In addition to being used for interchange among legacy distribution content
+formats, TTML Content may be used directly as a distribution format, providing, for
+example, a standard content format to reference from a <code>&lt;track&gt;</code>
+element in an HTML5 document, or a <code>&lt;text&gt;</code> or 
+<code>&lt;textstream&gt;</code> media element in a <a href="#smil3">[SMIL 3.0]</a> document. Certain properties of TTML support
+streamability of content, as described in <a href="#streaming"><b>O Streaming TTML Content</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>While TTML is not expressly designed for direct (embedded) integration into an
+HTML or a SMIL document instance, such integration is not precluded.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>In some contexts of use, it may be appropriate to employ
+animated content to depict sign language representations of the same content
+as expressed by a Timed Text <a href="#terms-document-instance">document instance</a>. This use case is not
+explicitly addressed by TTML mechanisms, but may be addressed by some
+external multimedia integration technology, such as SMIL.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>In previous drafts of this specification, TTML was referred to as DFXP (Distribution
+Format Exchange Profile). This latter term is retained for historical reasons in
+certain contexts, such as profile names and designators, and the short name
+<code>ttaf1-dfxp</code> used in URLs to refer to this specification.</p></div><div class="div2">
+<h3><a id="model"></a>1.1 System Model</h3><p>Use of TTML is intended to function in a wider context of Timed Text
+Authoring and Distribution mechanisms that are based upon the system
+model depicted in <a href="#model-graphic"><b>Figure 1 – System Model</b></a>, wherein the Timed Text Markup Language
+serves as a bidirectional interchange format among a heterogeneous collection of
+authoring systems, and as a unidirectional interchange format to a
+heterogeneous collection of distribution formats after undergoing transcoding
+or compilation to the target distribution formats as required, and where one
+particular distribution format is TTML (labeled as "DFXP" in the figure).</p><a id="model-graphic"></a><table class="example-images"><caption>Figure 1 – System Model</caption><tbody><tr><td><img src="images/model.png" alt="System Model"></td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Revise System Model"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Revise System Model</b></td><td align="right" valign="top">2014-11-27</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Update system model diagram to reflect current and expected usage. Eliminate reference to DFXP.</td></tr></table></div><div class="div2">
+<h3><a id="example"></a>1.2 Document Example</h3><p>A TTML <a href="#terms-document-instance">document instance</a> consists of a <code>tt</code> document element that contains
+a header and a body, where the header specifies document level metadata, styling
+definitions and layout definitions, and the body specifies text content intermixed
+with references to style and layout information and inline styling and timing information.</p><a id="ttml-example-document-structure"></a><table class="example"><caption>Example Fragment – TTML Document Structure</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head&gt;
+    &lt;metadata/&gt;
+    &lt;styling/&gt;
+    &lt;layout/&gt;
+  &lt;/head&gt;
+  &lt;body/&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p>Document level metadata may specify a document title, description,
+and copyright information. In addition, arbitrary metadata drawn from
+other namespaces may be specified.</p><a id="ttml-example-metadata"></a><table class="example"><caption>Example Fragment – TTML Metadata</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+  &lt;ttm:title&gt;Timed Text TTML Example&lt;/ttm:title&gt;
+  &lt;ttm:copyright&gt;The Authors (c) 2006&lt;/ttm:copyright&gt;
+&lt;/metadata&gt;
+</pre></div>
+</td></tr></tbody></table><p>Styling information may be specified in the form of style specification
+definitions that are referenced by layout and content information,
+specified inline with content information, or both.</p><p>In <a href="#ttml-example-styling"><b>Example Fragment – TTML Styling</b></a>, four style sets of specifications
+are defined, with one set serving as a collection of default styles.</p><a id="ttml-example-styling"></a><table class="example"><caption>Example Fragment – TTML Styling</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;styling xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;!-- s1 specifies default color, font, and text alignment --&gt;
+  &lt;style xml:id="s1"
+    tts:color="white"
+    tts:fontFamily="proportionalSansSerif"
+    tts:fontSize="22px"
+    tts:textAlign="center"
+  /&gt;
+  &lt;!-- alternative using yellow text but otherwise the same as style s1 --&gt;
+  &lt;style xml:id="s2" style="s1" tts:color="yellow"/&gt;
+  &lt;!-- a style based on s1 but justified to the right --&gt;
+  &lt;style xml:id="s1Right" style="s1" tts:textAlign="end" /&gt;     
+  &lt;!-- a style based on s2 but justified to the left --&gt;
+  &lt;style xml:id="s2Left" style="s2" tts:textAlign="start" /&gt;
+&lt;/styling&gt;
+</pre></div>
+</td></tr></tbody></table><p>Layout information defines one or more regions into which content
+is intended to be presented. A region definition may reference one or
+more sets of style specifications in order to permit content flowed in the
+region to inherit from these styles.
+In <a href="#ttml-example-layout"><b>Example Fragment – TTML Layout</b></a>, the region definition makes
+reference to style specification <code>s1</code> augmented by specific inline
+styles which, together, allow content flowed into the region to inherit
+from the region's styles (in the case
+that a style is not already explicitly specified on content or inherited
+via the content hierarchy.)</p><a id="ttml-example-layout"></a><table class="example"><caption>Example Fragment – TTML Layout</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;layout xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;region xml:id="subtitleArea"
+    style="s1"
+    tts:extent="560px 62px"
+    tts:padding="5px 3px"
+    tts:backgroundColor="black"
+    tts:displayAlign="after"
+  /&gt;
+&lt;/layout&gt;  
+</pre></div>
+</td></tr></tbody></table><p>The content of a <a href="#terms-document-instance">document instance</a> is expressed in its
+body, which is organized in terms of block and inline text elements.
+The hierarchical organization of content elements serves a primary role in
+determining both spatial and temporal relationships. For example, in
+<a href="#ttml-example-body"><b>Example Fragment – TTML Body</b></a>, each paragraph (<code>p</code> element)
+is flowed into its target region in the specified lexical order; furthermore,
+the active time interval of each paragraph is timed in accordance to its
+parent or sibling according to the applicable time containment semantics —
+in this case, the division parent is interpreted (by default) as a parallel time
+container.</p><a id="ttml-example-body"></a><table class="example"><caption>Example Fragment – TTML Body</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;body region="subtitleArea"&gt;
+  &lt;div&gt;
+    &lt;p xml:id="subtitle1" begin="0.76s" end="3.45s"&gt;
+      It seems a paradox, does it not,
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle2" begin="5.0s" end="10.0s"&gt;
+      that the image formed on&lt;br/&gt;
+      the Retina should be inverted?
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle3" begin="10.0s" end="16.0s" style="s2"&gt;
+      It is puzzling, why is it&lt;br/&gt;
+      we do not see things upside-down?
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle4" begin="17.2s" end="23.0s"&gt;
+      You have never heard the Theory,&lt;br/&gt;
+      then, that the Brain also is inverted?
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle5" begin="23.0s" end="27.0s" style="s2"&gt;
+      No indeed! What a beautiful fact!
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle6a" begin="28.0s" end="34.6s" style="s2Left"&gt;
+      But how is it proved?
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle6b" begin="28.0s" end="34.6s" style="s1Right"&gt;
+      Thus: what we call
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle7" begin="34.6s" end="45.0s" style="s1Right"&gt;
+      the vertex of the Brain&lt;br/&gt;
+      is really its base
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle8" begin="45.0s" end="52.0s" style="s1Right"&gt;
+      and what we call its base&lt;br/&gt;
+      is really its vertex,
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle9a" begin="53.5s" end="58.7s"&gt;
+      it is simply a question of nomenclature.
+    &lt;/p&gt;
+    &lt;p xml:id="subtitle9b" begin="53.5s" end="58.7s" style="s2"&gt;
+      How truly delightful!
+    &lt;/p&gt;
+  &lt;/div&gt;    
+&lt;/body&gt;
+</pre></div>
+</td></tr></tbody></table><p>The first subtitle <a href="#ttml-example-subtitle-1"><b>Subtitle 1 – Time Interval [0.76, 3.45)</b></a> is
+presented during the time interval 0.76 to 3.45 seconds.
+This
+subtitle inherits its font family, font size,
+foreground color, and text alignment from the region into which it is
+presented. Since no region is explicitly specified on the paragraph,
+the nearest ancestor that specifies a region determines the
+targeted region. Note also that content is presented
+at the bottom (after edge) of the containing region due to the <code>tts:displayAlign="after"</code>
+being specified on the region definition.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The notation "[<em>X</em>,<em>Y</em>]" denotes a closed
+interval from <em>X</em> to <em>Y</em>, including
+<em>X</em> and <em>Y</em>;
+"[<em>X</em>,<em>Y</em>)" denotes a right half-open
+interval from <em>X</em> to <em>Y</em>, including
+<em>X</em> but not including <em>Y</em>;
+"(<em>X</em>,<em>Y</em>]" denotes a left half-open
+interval from <em>X</em> to <em>Y</em>, not including
+<em>X</em> but including <em>Y</em>;
+"(<em>X</em>,<em>Y</em>)" denotes an open
+interval from <em>X</em> to <em>Y</em>, not including
+<em>X</em> or <em>Y</em>.
+</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>In this example, the <code>p</code> element is used as a presentational
+element rather than as a semantic element, i.e., as a linguistic paragraph.
+It is up to an author to determine which TTML elements are used to convey
+the intended meaning. For instance, this example could be written to use
+timing on <code>span</code> elements in order to preserve the integrity of
+semantic paragraphs.</p></div><a id="ttml-example-subtitle-1"></a><table class="example-images"><caption>Subtitle 1 – Time Interval [0.76, 3.45)</caption><tbody><tr><td><img src="images/subtitle1.png" alt="Subtitle 1"></td></tr></tbody></table><p>The second subtitle continues with the default style, except that it contains
+two lines of text with an intervening author-specified line break. Note the effects of
+the use of <code>tts:textAlign="center"</code> to specify the paragraph's alignment
+in the inline progression direction.</p><a id="ttml-example-subtitle-2"></a><table class="example-images"><caption>Subtitle 2 – Time Interval [5.0, 10.0)</caption><tbody><tr><td><img src="images/subtitle2.png" alt="Subtitle 2"></td></tr></tbody></table><p>The third subtitle continues, using a variant style which overrides the default style's
+foreground color with a different color.</p><a id="ttml-example-subtitle-3"></a><table class="example-images"><caption>Subtitle 3 – Time Interval [10.0, 16.0)</caption><tbody><tr><td><img src="images/subtitle3.png" alt="Subtitle 3"></td></tr></tbody></table><p>The fourth subtitle reverts to the default style.</p><a id="ttml-example-subtitle-4"></a><table class="example-images"><caption>Subtitle 4 – Time Interval [17.2, 23.0)</caption><tbody><tr><td><img src="images/subtitle4.png" alt="Subtitle 4"></td></tr></tbody></table><p>The fifth subtitle continues, again using a variant style which
+overrides the default style's foreground color with a different color.</p><a id="ttml-example-subtitle-5"></a><table class="example-images"><caption>Subtitle 5 – Time Interval [23.0, 27.0)</caption><tbody><tr><td><img src="images/subtitle5.png" alt="Subtitle 5"></td></tr></tbody></table><p>During the next active time interval, two distinct subtitles are simultaneously active, with
+the paragraphs expressing each subtitle using different styles that override color and paragraph
+text alignment of the default style. Note that the flow order is determined by the lexical
+order of elements as they appear in the content hierarchy.</p><a id="ttml-example-subtitle-6"></a><table class="example-images"><caption>Subtitles 6a and 6b – Time Interval [28.0, 34.6)</caption><tbody><tr><td><img src="images/subtitle6.png" alt="Subtitles 6a and 6b"></td></tr></tbody></table><p>The next subtitle is specified in a similar manner using
+a style override to give the paragraph right (end) justification in the
+inline progression direction.</p><a id="ttml-example-subtitle-7"></a><table class="example-images"><caption>Subtitle 7 – Time Interval [34.6, 45.0)</caption><tbody><tr><td><img src="images/subtitle7.png" alt="Subtitles 7a and 7b"></td></tr></tbody></table><p>The eighth subtitle uses the same style override as the previous
+subtitle in order to maintain the right (end) justification of the
+paragraph.</p><a id="ttml-example-subtitle-8"></a><table class="example-images"><caption>Subtitle 8 – Time Interval [47.3, 49.0)</caption><tbody><tr><td><img src="images/subtitle8.png" alt="Subtitle 8"></td></tr></tbody></table><p>During the final (ninth) active time interval, two distinct
+subtitles are again simultaneously active, but with a different
+style applied to the second paragraph to override the default color.
+Note that the flow order is determined by the lexical order of
+elements as they appear in the content hierarchy.</p><a id="ttml-example-subtitle-9"></a><table class="example-images"><caption>Subtitles 9a and 9b – Time Interval [53.5, 58.7)</caption><tbody><tr><td><img src="images/subtitle9.png" alt="Subtitles 9a and 9b"></td></tr></tbody></table><p>The examples shown above demonstrate the primary types of information that may
+be authored using TTML: metadata, styling, layout, timing, and content. In typical cases,
+styling and layout information are separately specified in a <a href="#terms-document-instance">document instance</a>. Content information
+is expressed in a hierarchical fashion that embodies the organization of both spatial (flow) and
+timing information. Content makes direct or indirect references to styling and layout information
+and may specify inline overrides to styling.</p></div></div><div class="div1">
+<h2><a id="definitions"></a>2 Definitions</h2><div class="div2">
+<h3><a id="acronyms"></a>2.1 Acronyms</h3><table class="acronyms" summary="Glossary List"><tr><td class="label"><b>DFXP</b></td><td class="def"><p>Distribution Format Exchange Profile</p></td></tr><tr><td class="label"><b>ISD</b></td><td class="def"><p>Intermediate Synchronic Document</p></td></tr><tr><td class="label"><b>TT</b></td><td class="def"><p>Timed Text</p></td></tr><tr><td class="label"><b>TTML</b></td><td class="def"><p>Timed Text Markup Language</p></td></tr><tr><td class="label"><b>TTAF</b></td><td class="def"><p>Timed Text Authoring Format</p></td></tr><tr><td class="label"><b>TTWG</b></td><td class="def"><p>Timed Text Working Group</p></td></tr></table></div><div class="div2">
+<h3><a id="terms"></a>2.2 Terminology</h3><dl><dt class="label"><a id="terms-abstract-document-instance"></a>[abstract document instance]</dt><dd><p>An instance of an abstract data set as represented by a
+<a href="#terms-reduced-xml-infoset">reduced xml infoset</a>.</p></dd><dt class="label"><a id="terms-abstract-document-type"></a>[abstract document type]</dt><dd><p>A set of constraints that defines a class of <em>XML Information
+Sets</em> <a href="#infoset">[XML InfoSet]</a>.</p></dd><dt class="label"><a id="terms-anonymous-profile"></a>[anonymous profile]</dt><dd><p>See <a href="#terms-undesignated-profile">undesignated profile</a>.</p></dd><dt class="label"><a id="terms-attribute-information-item"></a>[attribute information item]</dt><dd><p>Each specified or defaulted attribute  of an XML document corresponds with an attribute information
+item as defined by <a href="#infoset">[XML InfoSet]</a>, §2.3.</p></dd><dt class="label"><a id="terms-audio-defining-context"></a>[audio defining context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element is specified to serve as
+a sharable definition to be referenced by another <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element
+in an <a href="#terms-audio-presentation-context">audio presentation context</a>.</p></dd><dt class="label"><a id="terms-audio-presentation-context"></a>[audio presentation context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element is specified for the
+purpose of being presented (rendered). Such an <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element
+may specify the audio data inline by using a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element within
+a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element child, or it may reference another
+<a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element specified in a 
+<a href="#terms-audio-definition-context">audio definition context</a>, or it may do both.</p></dd><dt class="label"><a id="terms-audio-resource"></a>[audio resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> that contains coded or unencoded audio samples.</p></dd><dt class="label"><a id="terms-authoring-viewport"></a>[authoring viewport]</dt><dd><p>A <a href="#terms-viewport">viewport</a> employed at authoring (content encoding) time.</p></dd><dt class="label"><a id="terms-baseline-profile"></a>[baseline profile]</dt><dd><p>A <a href="#terms-profile">profile</a> referenced by the <code>use</code> attribute of a <code>ttp:profile</code> element,
+which serves as a baseline (initial) set of specifications with which to populate the referencing profile.</p></dd><dt class="label"><a id="terms-block-display"></a>[block display]</dt><dd><p>Block display is a set of layout semantics that may be applied to a <a href="#terms-content-element">content element</a> in
+certain contexts, wherein child areas are composed sequentially in the block progression direction. In <a href="#css2">[CSS2]</a>,
+block display is indicated when a CSS <code>display</code> property with the value <code>block</code> is applied to a
+<a href="#terms-content-element">content element</a> during presentation processing. In <a href="#xsl11">[XSL 1.1]</a>, a block display
+occurs when composing a <code>fo:block</code> element.</p></dd><dt class="label"><a id="terms-character-information-item"></a>[character information item]</dt><dd><p>Each data character appearing in an XML document corresponds with a character information
+item as defined by <a href="#infoset">[XML InfoSet]</a>, §2.6.</p></dd><dt class="label"><a id="terms-chunked-data-embedding"></a>[chunked data embedding]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element that directly embeds a representation of the actual bytes
+of an <a href="#terms-embedded-data-resource">embedded data resource</a> by making use of a
+child <a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a> element.</p></dd><dt class="label"><a id="terms-computed-cell-size"></a>[computed cell size]</dt><dd><p>The size (extent) of a cell computed by dividing the width of the <a href="#terms-root-container-region">root container region</a>
+by the column count, i.e., the number of cells in the horizontal axis, and by dividing
+the height of the <a href="#terms-root-container-region">root container region</a> by the row count, i.e., the number of cells in the vertical
+axis, where the column and row counts are determined by the <code>ttp:cellResolution</code> parameter attribute.</p></dd><dt class="label"><a id="terms-content-element"></a>[content element]</dt><dd><p>Any of the element types defined by the <a href="#element-vocab-type-content">Content Module</a>.</p></dd><dt class="label"><a id="terms-content-image"></a>[content image]</dt><dd><p>An <a href="#terms-image-resource">image resource</a> that contains semantically significant content, e.g., a raster image
+representing the rendering of a caption.</p></dd><dt class="label"><a id="terms-content-processor"></a>[content processor]</dt><dd><p>A processing system capable of importing (receiving) Timed Text Markup Language
+content for the purpose of transforming, presenting, or otherwise processing the content.</p></dd><dt class="label"><a id="terms-content-profile"></a>[content profile]</dt><dd><p>A collection of <a href="#terms-feature">features</a> and <a href="#terms-extension">extensions</a> that must not, must, or may be employed by
+Timed Text Markup Language content.</p><p></p></dd><dt class="label"><a id="terms-content-region"></a>[content region]</dt><dd><p>A logical region into which rendered content is placed when modeling or
+performing presentation processing.</p><table border="1" class="ednote" summary="Editorial note: Content Region vs Region"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Content Region vs Region</b></td><td align="right" valign="top">2014-12-10</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Clean up terminology regarding content region vs region, which difference is vague at best.</td></tr></table><p></p></dd><dt class="label"><a id="terms-data-binding-context"></a>[data binding context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-data"><code>data</code></a> element is specified for the
+purpose of semantic binding (association). Such a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element
+may specify the data inline by using a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element within
+a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element child, or it may reference another
+<a href="#embedded-content-vocabulary-data"><code>data</code></a> element specified in a 
+<a href="#terms-data-definition-context">data definition context</a>, or it may do both. No presentation (rendering)
+semantics are implied by the mere presence of a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element in this (or any) context.</p></dd><dt class="label"><a id="terms-data-binding-context-for-metadata"></a>[data binding context for metadata]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element the parent of which is a
+<a href="#metadata-vocabulary-metadata"><code>metadata</code></a> element.</p></dd><dt class="label"><a id="terms-data-binding-context-for-source"></a>[data binding context for source]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element the parent of which is a
+<a href="#embedded-content-vocabulary-source"><code>source</code></a> element.</p></dd><dt class="label"><a id="terms-data-defining-context"></a>[data defining context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-data"><code>data</code></a> element is specified to serve as
+a sharable definition to be referenced by another <a href="#embedded-content-vocabulary-data"><code>data</code></a> element
+in an <a href="#terms-data-binding-context">data binding context</a>, namely, a
+<a href="#embedded-content-vocabulary-data"><code>data</code></a> element the parent of which is a
+<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element.</p></dd><dt class="label"><a id="terms-data-element"></a>[data element]</dt><dd><p>Any of the element types defined by the <a href="#element-vocab-type-data">Data Module</a>.</p></dd><dt class="label"><a id="terms-data-resource"></a>[data resource]</dt><dd><p>An arbitrary data resource represented or referenced using a <a href="#terms-data-element">data element</a>. For example,
+a data resource may be used to embed or refer to an audio clip, a font, an image, or arbitrary application data in a
+<a href="#terms-timed-text-content-document-instance">timed text content document instance</a>.</p></dd><dt class="label"><a id="terms-default-profile"></a>[default processor profile]</dt><dd><p>A default <a href="#terms-processor-profile">processor profile</a> used to compute an
+<a href="#terms-effective-processor-profile">effective processor profile</a> in the absence of a declared or inferred
+<a href="#terms-processor-profile">processor profile</a>, where this default processor profile is determined by
+the <a href="#semantics-procedure-construct-default-processor-profile"><span class="strong">construct default processor profile</span></a>
+procedure.</p></dd><dt class="label"><a id="terms-default-region"></a>[default region]</dt><dd><p>A default <a href="#terms-out-of-line-region">out-of-line region</a> that is implied in the absence of
+an explicitly specified out-of-line <a href="#layout-vocabulary-region"><code>region</code></a> element, i.e.,
+when no <a href="#layout-vocabulary-region"><code>region</code></a> element is specified as a child of
+a <a href="#layout-vocabulary-layout"><code>layout</code></a> element.</p></dd><dt class="label"><a id="terms-designated-profile"></a>[designated profile]</dt><dd><p>A <a href="#terms-profile">profile</a> that is associated with a <a href="#terms-profile-designator">profile designator</a> by
+means of a <code>designator</code> attribute or prose text in a specification of profile.</p></dd><dt class="label"><a id="terms-display-aspect-ratio"></a>[display aspect ratio]</dt><dd><p>The ratio between the horizontal dimension and vertical dimension of a displayed image, video frame,
+viewport or region, display device, etc. Equal to the product of <a href="#terms-storage-aspect-ratio">storage aspect ratio</a>
+and <a href="#terms-pixel-aspect-ratio">pixel aspect ratio</a>.</p></dd><dt class="label"><a id="terms-display-region-target"></a>[display region target]</dt><dd><p>A <a href="#terms-viewport">viewport</a> targeted to a rectangular region of a display device, i.e., not in full-screen mode.</p></dd><dt class="label"><a id="terms-display-target"></a>[display target]</dt><dd><p>A <a href="#terms-viewport">viewport</a> targeted to a display device as a whole, i.e., in full-screen mode.</p></dd><dt class="label"><a id="terms-document-coordinate-space"></a>[document coordinate space]</dt><dd><p></p><table border="1" class="ednote" summary="Editorial note: Document Coordinate Space Definition"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Document Coordinate Space Definition</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Either define or express in terms of (some) viewport.</td></tr></table><p></p></dd><dt class="label"><a id="terms-document-instance"></a>[document instance]</dt><dd><p>A <a href="#terms-timed-text-document-instance">timed text document instance</a>.</p></dd><dt class="label"><a id="terms-document-interchange-context"></a>[document interchange context]</dt><dd><p>The implied context or environment external to a <a href="#terms-content-processor">content processor</a> in
+which document interchange occurs, and in which out-of-band protocols or specifications
+may define certain behavioral defaults, such as an implied profile.</p></dd><dt class="label"><a id="terms-document-processing-context"></a>[document processing context]</dt><dd><p>The implied context or environment internal to a <a href="#terms-content-processor">content processor</a> in
+which document processing occurs, and in which out-of-band protocols or specifications
+may define certain behavioral defaults, such as the establishment or creation of a
+<a href="#terms-synthetic-document-syncbase">synthetic document syncbase</a>.</p></dd><dt class="label"><a id="terms-dot-pitch"></a>[dot pitch]</dt><dd><p>Depending upon display device technology, the distance between holes in the shadow mask, the distance between wires in the aperture grill,
+the distance between sub-pixels of the same color, etc.</p></dd><dt class="label"><a id="terms-effective-content-profile"></a>[effective content profile]</dt><dd><p>The <a href="#terms-content-profile">content profile</a> computed from the set of all <a href="#terms-content-profile">content profiles</a>
+explicitly or implicitly referenced by or assigned to a TTML <a href="#terms-document-instance">document instance</a> after applying any
+explicit or implicit profile and profile specification combination methods. When performing validation on a given <a href="#terms-document-instance">document instance</a>,
+then this validation is performed by making use of a document's <a href="#terms-effective-content-profile">effective content profile</a>.</p></dd><dt class="label"><a id="terms-effective-processor-profile"></a>[effective processor profile]</dt><dd><p>The <a href="#terms-processor-profile">processor profile</a> computed from the set of all <a href="#terms-processor-profile">processor profiles</a>
+explicitly or implicitly referenced by or assigned to a TTML <a href="#terms-document-instance">document instance</a> after applying any
+explicit or implicit profile and profile specification combination methods. When determining if a <a href="#terms-content-processor">content processor</a>
+can or cannot process a given <a href="#terms-document-instance">document instance</a>, then this determination is performed
+by making use of a document's <a href="#terms-effective-processor-profile">effective processor profile</a>.</p></dd><dt class="label"><a id="terms-element-information-item"></a>[element information item]</dt><dd><p>Each element appearing in an XML document corresponds with an element information
+item as defined by <a href="#infoset">[XML InfoSet]</a>, §2.2.</p></dd><dt class="label"><a id="terms-embedded-content-element"></a>[embedded content element]</dt><dd><p>Any of the element types defined by the <a href="#element-vocab-type-audio">Audio Module</a>,
+<a href="#element-vocab-type-data">Data Module</a>,
+<a href="#element-vocab-type-font">Font Module</a>, or
+<a href="#element-vocab-type-image">Image Module</a>.</p></dd><dt class="label"><a id="terms-embedded-data-resource"></a>[embedded data resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> embedded in a
+<a href="#terms-timed-text-content-document-instance">timed text content document instance</a>, represented by means of
+a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element, whether or not that
+<a href="#embedded-content-vocabulary-data"><code>data</code></a> element represents the actual bytes of the <a href="#terms-data-resource">data resource</a>
+or refers to an <a href="#terms-external-data-resource">external data resource</a>
+</p></dd><dt class="label"><a id="terms-enclosing-document-instance"></a>[enclosing document instance]</dt><dd><p>The <a href="#terms-document-instance">document instance</a> that encloses or otherwise contains
+an enclosed feature or component.</p></dd><dt class="label"><a id="terms-exchange-profile"></a>[exchange profile]</dt><dd><p>A profile of content that serves a set of needs for content interchange.</p></dd><dt class="label"><a id="terms-extension"></a>[extension]</dt><dd><p>A syntactic or semantic expression or capability that is defined and
+labeled (using a extension designation) in another (public or private)
+specification.</p></dd><dt class="label"><a id="terms-extension-specification"></a>[extension specification]</dt><dd><p>A specification of a constraint or requirement that relates to an
+<a href="#terms-extension">extension</a>, typically expressed by
+an <a href="#profile-vocabulary-extension"><code>ttp:extension</code></a> element.</p></dd><dt class="label"><a id="terms-external-data-resource"></a>[external data resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> external to a
+<a href="#terms-timed-text-content-document-instance">timed text content document instance</a>, referenced by means
+of a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element or a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute
+of a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element or <a href="#terms-embedded-content-element">embedded content element</a>.</p></dd><dt class="label"><a id="terms-external-source"></a>[external source]</dt><dd><p>Either (1) a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element or a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute
+that refers to an <a href="#terms-external-data-resource">external data resource</a> or (2) the referenced
+<a href="#terms-external-data-resource">external data resource</a>.</p></dd><dt class="label"><a id="terms-feature"></a>[feature]</dt><dd><p>A syntactic or semantic expression or capability that is defined and
+labeled (using a feature designation) in this specification (or a past or
+future revision of this specification).</p></dd><dt class="label"><a id="terms-feature-specification"></a>[feature specification]</dt><dd><p>A specification of a constraint or requirement that relates to an
+<a href="#terms-feature">feature</a>, typically expressed by
+an <a href="#profile-vocabulary-feature"><code>ttp:feature</code></a> element.</p></dd><dt class="label"><a id="terms-forced-subtitle"></a>[forced subtitle]</dt><dd><p>A subtitle (or caption) that is intended to always be displayed even if subtitles (captions) are not enabled. Forced subtitles (captions)
+are used to prevent open captioning of, i.e., burning in, subtitles (captions) related to foreign or alien language or translation of text
+that appears in media, such as in a sign.</p></dd><dt class="label"><a id="terms-font-defining-context"></a>[font defining context]</dt><dd><p>The context in which a <a href="#embedded-content-vocabulary-font"><code>font</code></a> element is specified to serve as
+a sharable definition to be referenced indirectly by a <a href="#terms-font-selection-process">font selection process</a>.</p></dd><dt class="label"><a id="terms-font-selection-process"></a>[font selection process]</dt><dd><p>An internal process used by a <a href="#terms-presentation-processor">presentation processor</a> which purpose is to select
+a set of author defined fonts and platform fonts for use during layout and presentation processing, where input parameters to this
+process include the computed values of font related properties, the capabilities of individual fonts, and the text content being presented.</p></dd><dt class="label"><a id="terms-font-resource"></a>[font resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> that contains font information, such as character to glyph mapping data, glyph outlines or images,
+glyph metrics, and other data used in the character to glyph mapping and rendering process.</p></dd><dt class="label"><a id="terms-fragment-identifier"></a>[fragment identifier]</dt><dd><p>A syntactic expression that adheres to the fragment identifer syntax defined by <a href="#uri">[URI]</a>,
+Section 4.1.</p></dd><dt class="label"><a id="terms-image-defining-context"></a>[image defining context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element is specified to serve as
+a sharable definition to be referenced by another <a href="#embedded-content-vocabulary-image"><code>image</code></a> element
+in an <a href="#terms-image-presentation-context">image presentation context</a>.</p></dd><dt class="label"><a id="terms-image-presentation-context"></a>[image presentation context]</dt><dd><p>The context in which an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element is specified for the
+purpose of being presented (rendered). Such an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element
+may specify the image data inline by using a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element within
+a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element child, or it may reference another
+<a href="#embedded-content-vocabulary-image"><code>image</code></a> element specified in a 
+<a href="#terms-image-definition-context">image definition context</a>, or it may do both.</p></dd><dt class="label"><a id="terms-image-resource"></a>[image resource]</dt><dd><p>A <a href="#terms-data-resource">data resource</a> that contains a raster image.</p></dd><dt class="label"><a id="terms-implied-inline-region"></a>[implied inline region]</dt><dd><p>An anonymous (unidentified) <a href="#terms-inline-region">inline region</a> that is implied in the context of a block level
+<a href="#terms-content-element">content element</a>
+due the presence of a <a href="#style-attribute-extent"><code>tts:extent</code></a> or <a href="#style-attribute-origin"><code>tts:origin</code></a>
+style attribute on the <a href="#terms-content-element">content element</a>.</p></dd><dt class="label"><a id="terms-inline-animation"></a>[inline animation]</dt><dd><p>An <a href="#animation-vocabulary-animate"><code>animate</code></a> or <a href="#animation-vocabulary-set"><code>set</code></a> element
+that is defined inline as an immediate child of
+a <a href="#terms-content-element">content element</a> or <a href="#layout-vocabulary-region"><code>region</code></a> element associated with the animation.
+There is a one-to-one relation between
+an inline animation element and its parent <a href="#terms-content-element">content element</a> or <a href="#layout-vocabulary-region"><code>region</code></a> element.</p></dd><dt class="label"><a id="terms-inline-block-display"></a>[inline block display]</dt><dd><p>Inline block display is a set of layout semantics that may be applied to a <a href="#terms-content-element">content element</a> in
+certain contexts, wherein a generated block area is treated as an an atomic area to be composed in an inline layout context, i.e., the block
+area is treated as if it were itself an inline area when considered externally, but as a block area which considered internally. In <a href="#css2">[CSS2]</a>,
+inline block display is indicated when a CSS <code>display</code> property with the value <code>inline-block</code> is applied to a
+<a href="#terms-content-element">content element</a> during presentation processing. In <a href="#xsl11">[XSL 1.1]</a>, an inline block display
+occurs when block content appears in an inline content context, e.g., when a <code>fo:block</code> appears as a child of <code>fo:inline</code>.</p></dd><dt class="label"><a id="terms-inline-display"></a>[inline display]</dt><dd><p>Inline display is a set of layout semantics that may be applied to a <a href="#terms-content-element">content element</a> in
+certain contexts, wherein child areas are composed sequentially in the inline progression direction. In <a href="#css2">[CSS2]</a>,
+inline display is indicated when a CSS <code>display</code> property with the value <code>inline</code> is applied to a
+<a href="#terms-content-element">content element</a> during presentation processing. In <a href="#xsl11">[XSL 1.1]</a>, an inline display
+occurs when composing a <code>fo:inline</code> element.</p></dd><dt class="label"><a id="terms-inline-region"></a>[inline region]</dt><dd><p>A <a href="#terms-region">region</a> that is defined in an inline manner with respect to some
+<a href="#terms-content-element">content element</a>  to be selected into (targeted to) the region.
+An inline region is specified either explicitly by a <a href="#layout-vocabulary-region"><code>region</code></a> element child of
+a <a href="#terms-content-element">content element</a> or implicitly by specifying a <a href="#style-attribute-extent">tts:extent</a>
+or <a href="#style-attribute-origin">tts:origin</a> style attribute on a <a href="#terms-content-element">content element</a>.
+There is a one-to-one relation between an inline <a href="#layout-vocabulary-region"><code>region</code></a> element and its
+parent <a href="#terms-content-element">content element</a>. An inline region is assigned its parent element's time interval as its active
+time interval. No <code>region</code> attribute makes reference to an inline region.</p></dd><dt class="label"><a id="terms-intermediate-synchronic-document"></a>[intermediate synchronic document]</dt><dd><p>A <a href="#terms-timed-text-intermediate-document">timed text intermediate document</a> or a
+<a href="#terms-timed-text-intermediate-document-instance">timed text intermediate document instance</a>, according to the context of use,
+where the root (document) element is an <code>isd:isd</code> element, and which represents a
+non-overlapping temporal interval that intersects with the content, styling, layout, and timing of a source
+<a href="#terms-timed-text-content-document">timed text content document</a>.</p></dd><dt class="label"><a id="terms-intermediate-synchronic-document-sequence"></a>[intermediate synchronic document sequence]</dt><dd><p>A <a href="#terms-timed-text-intermediate-document">timed text intermediate document</a> or a
+<a href="#terms-timed-text-intermediate-document-instance">timed text intermediate document instance</a>, according to the context of use,
+where the root (document) element is an <code>isd:sequence</code> element, and which represents a
+sequence of <a href="#terms-intermediate-synchronic-document">intermediate synchronic document</a> instances
+that effectively represent the content, styling, layout, and timing of a source <a href="#terms-timed-text-content-document">timed text content document</a>.</p></dd><dt class="label"><a id="terms-intermediate-document-syntax"></a>[intermediate document syntax]</dt><dd><p>A formalism for use in the concrete representation of an <a href="#terms-intermediate-synchronic-document-sequence">intermediate synchronic document sequence</a> or
+an <a href="#terms-intermediate-synchronic-document">intermediate synchronic document</a>.</p></dd><dt class="label"><a id="terms-nested-profile"></a>[nested profile]</dt><dd><p>A constituent <a href="#terms-profile">profile</a> of a <a href="#terms-nesting-profile">nesting profile</a>, i.e., one of the
+descendant <code>ttp:profile</code> element(s) of a higher level (ancestor) <code>ttp:profile</code> element. A given <code>ttp:profile</code> may serve
+as both a <a href="#terms-nested-profile">nested profile</a> and a <a href="#terms-nesting-profile">nesting profile</a>.</p></dd><dt class="label"><a id="terms-nesting-profile"></a>[nesting profile]</dt><dd><p>A <a href="#terms-profile">profile</a> defined by making reference to one or more child <code>ttp:profile</code> element(s), wherein a
+profile combination method determines how profile specifications from the multiple child <code>ttp:profile</code> element(s) are combined.</p></dd><dt class="label"><a id="terms-nested-embedded-source"></a>[nested embedded source]</dt><dd><p>A <a href="#embedded-content-vocabulary-source"><code>source</code></a> element that specifies a child 
+<a href="#embedded-content-vocabulary-data"><code>data</code></a> element which embeds the actual bytes of the
+<a href="#terms-embedded-data-resource">embedded data resource</a>, whether by 
+<a href="#terms-simple-data-embedding">simple data embedding</a> or <a href="#terms-chunked-data-embedding">chunked data embedding</a>.</p></dd><dt class="label"><a id="terms-non-content-image"></a>[non-content image]</dt><dd><p>An <a href="#terms-image-resource">image resource</a> that does not contain semantically significant content, e.g., a raster image
+representing a background design, which, if not presented, would not affect the presentation of semntically significant content.</p></dd><dt class="label"><a id="terms-non-nested-embedded-source"></a>[non-nested embedded source]</dt><dd><p>A <a href="#embedded-content-vocabulary-source"><code>source</code></a> element that specifies a child 
+<a href="#embedded-content-vocabulary-data"><code>data</code></a> element which does not embed a representation of the actual bytes of the
+<a href="#terms-embedded-data-resource">embedded data resource</a>.</p></dd><dt class="label"><a id="terms-non-nesting-profile"></a>[non-nesting profile]</dt><dd><p>A <a href="#terms-profile">profile</a> defined without making reference to one or more child <code>ttp:profile</code> element(s); that is,
+by including only child <code>ttp:features</code> and <code>ttp:extensions</code> element(s).</p></dd><dt class="label"><a id="terms-out-of-line-animation"></a>[out-of-line animation]</dt><dd><p>An <a href="#animation-vocabulary-animate"><code>animate</code></a> or <a href="#animation-vocabulary-set"><code>set</code></a> element that is defined out-of-line from
+the <a href="#terms-content-element">content element</a> or <a href="#layout-vocabulary-region"><code>region</code></a> element associated with the animation.
+An out-of-line animation appears as a child of an <a href="#animation-vocabulary-animation"><code>animation</code></a> element in the header
+(<a href="#document-structure-vocabulary-head"><code>head</code></a> element)
+of a <a href="#terms-document-instance">document instance</a>, and specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute
+which value is referenced by an <a href="#animation-attribute-animate"><code>animate</code></a> attribute
+on the associated element to be animated. There is a one-to-many relation between
+a referenced out-of-line animation element and referencing <a href="#terms-content-element">content elements</a> and
+<a href="#layout-vocabulary-region"><code>region</code></a> elements.</p></dd><dt class="label"><a id="terms-out-of-line-region"></a>[out-of-line region]</dt><dd><p>A <a href="#layout-vocabulary-region"><code>region</code></a> element that is defined out-of-line from
+a <a href="#terms-content-element">content element</a> associated with (to be selected into) the region.
+An out-of-line region appears as a child of a <a href="#layout-vocabulary-layout"><code>layout</code></a> element in the header
+(<a href="#document-structure-vocabulary-head"><code>head</code></a> element)
+of a <a href="#terms-document-instance">document instance</a>, and specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute
+which value is referenced by a <a href="#layout-attribute-region"><code>region</code></a> attribute
+on the associated element to be selected into the region. There is a one-to-many relation between
+a referenced out-of-line region element and referencing <a href="#terms-content-element">content elements</a>.
+A <a href="#terms-default-region">default out-of-line region</a> is implied if no
+<a href="#terms-out-of-line-region">out-of-line region</a> is specified explicitly.</p></dd><dt class="label"><a id="terms-pixel-aspect-ratio"></a>[pixel aspect ratio]</dt><dd><p>The ratio between the horizontal dimension and vertical dimension of a displayed pixel. Note that the dimensions of a display pixel may or may not
+correspond to the <a href="#terms-dot-pitch">dot pitch</a> of the display device on which it is rendered.</p></dd><dt class="label"><a id="terms-presentation-context-coordinate-space"></a>[presentation context coordinate space]</dt><dd><p></p><table border="1" class="ednote" summary="Editorial note: Presentation Context Coordinate Space Definition"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Presentation Context Coordinate Space Definition</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Either define or express in terms of (some) viewport.</td></tr></table><p></p></dd><dt class="label"><a id="terms-presentation-processor"></a>[presentation processor]</dt><dd><p>A <a href="#terms-content-processor">content processor</a> which purpose is to layout, format, and render,
+i.e., to present, <a href="#terms-timed-text-markup-language">Timed Text Markup Language</a> content by applying the presentation semantics
+defined in this specification.</p></dd><dt class="label"><a id="terms-presentation-viewport"></a>[presentation viewport]</dt><dd><p>A <a href="#terms-viewport">viewport</a> employed at presentation (content decoding) time.</p><p>Note well that the characteristics of a <a href="#presentation-viewport">presentation viewport</a> may or may not
+match the characteristics of the <a href="#authoring-viewport">authoring viewport</a> used when content was authored (encoded).
+In particular, the <a href="#terms-storage-aspect-ratio">storage aspect ratio</a> and (or) the <a href="#terms-pixel-aspect-ratio">pixel aspect ratio</a>
+of the former may differ from that of the latter.</p></dd><dt class="label"><a id="terms-processor"></a>[processor]</dt><dd><p>See <a href="#terms-content-processor">content processor</a>.</p></dd><dt class="label"><a id="terms-processor-profile"></a>[processor profile]</dt><dd><p>A collection of <a href="#terms-feature">features</a> and <a href="#terms-extension">extensions</a> that must or may be implemented (supported) by
+a content processor.</p></dd><dt class="label"><a id="terms-profile"></a>[profile]</dt><dd><p>A <a href="#terms-content-profile">content profile</a> or <a href="#terms-processor-profile">processor profile</a>.</p></dd><dt class="label"><a id="terms-profile-definition-document"></a>[profile definition document]</dt><dd><p>A <a href="#terms-timed-text-profile-document">timed text profile document</a> or a
+<a href="#terms-timed-text-profile-document-instance">timed text profile document instance</a>, according to the context of use.</p></dd><dt class="label"><a id="terms-profile-designator"></a>[profile designator]</dt><dd><p>An absolute URI used to label or reference an externally defined <a href="#terms-profile">profile</a>, where
+external refers to being external to a <a href="#terms-document-instance">document instance</a>.</p></dd><dt class="label"><a id="terms-profile-fragment-identifier"></a>[profile fragment identifier]</dt><dd><p>A <a href="#terms-fragment-identifier">fragment identifier</a> used to label or reference an internally defined <a href="#terms-profile">profile</a>, where
+internal refers to being internal to a <a href="#terms-document-instance">document instance</a>.</p></dd><dt class="label"><a id="terms-profile-specification"></a>[profile specification]</dt><dd><p>A <a href="#terms-feature-specification">feature specification</a> or an <a href="#terms-extension-specification">extension specification</a>
+or the internal state representation thereof.</p></dd><dt class="label"><a id="terms-region"></a>[region]</dt><dd><p>A logical construct that models authorial intention regarding
+desired or potential presentation processing, and which is represented as
+a rectangular area of a presentation surface into which content
+is composed and rendered during presentation processing.</p></dd><dt class="label"><a id="terms-reduced-xml-infoset"></a>[reduced xml infoset]</dt><dd><p>An XML Information Set <a href="#infoset">[XML InfoSet]</a> that satisfies the
+constraints specify by <a href="#reduced-infoset"><b>B Reduced XML Infoset</b></a>.</p></dd><dt class="label"><a id="terms-related-media-object"></a>[related media object]</dt><dd><p>A (possibly null) media object associated with or otherwise related
+to a <a href="#terms-document-instance">document instance</a>. For example, an aggregate audio/video media
+object for which a <a href="#terms-document-instance">document instance</a> provides caption or subtitle
+information, and with which that <a href="#terms-document-instance">document instance</a> is associated.</p></dd><dt class="label"><a id="terms-related-media-object-region"></a>[related media object region]</dt><dd><p>When a non-null <a href="#terms-related-media-object">related media object</a> exists, the region of this media object,
+expressed in the coordinate system that applies to the <a href="#terms-document-instance">document instance</a> that is associated with the
+related media object.</p><table border="1" class="ednote" summary="Editorial note: Update Definition of Related Media Object Region"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Update Definition of Related Media Object Region</b></td><td align="right" valign="top">2014-12-02</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Untangle definition from use of document coordinate space.</td></tr></table><p></p></dd><dt class="label"><a id="terms-related-media-object-region-target"></a>[related media object region target]</dt><dd><p>A <a href="#terms-viewport">viewport</a> targeted to a <a href="#terms-related-media-object-region">related media object region</a>.</p></dd><dt class="label"><a id="terms-root-container-region"></a>[root container region]</dt><dd><p>A logical region that establishes a coordinate system into which
+<a href="#terms-content-region">content regions</a> are placed and optionally clipped.</p></dd><dt class="label"><a id="terms-root-temporal-extent"></a>[root temporal extent]</dt><dd><p>The temporal extent (interval) defined by the temporal beginning and ending of a <a href="#terms-document-instance">document instance</a>
+in relationship with some external application or presentation context.</p></dd><dt class="label"><a id="terms-simple-data-embedding"></a>[simple data embedding]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element the directly embeds a representation of the actual bytes
+of an <a href="#terms-embedded-data-resource">embedded data resource</a> without making use of a
+child <a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a> element.</p></dd><dt class="label"><a id="terms-smpte-time-code"></a>[smpte time code]</dt><dd><p>A time code whose format and semantics are established by <a href="#smpte12m">[SMPTE 12M]</a>,
+which may be embedded into or otherwise associated with media content, such
+as a broadcast audio/video stream.</p></dd><dt class="label"><a id="terms-sourced-data-embedding"></a>[sourced data embedding]</dt><dd><p>A <a href="#embedded-content-vocabulary-data"><code>data</code></a> element that indirectly references the content
+of an <a href="#terms-embedded-data-resource">embedded data resource</a> by making use of a
+child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element.</p></dd><dt class="label"><a id="terms-storage-aspect-ratio"></a>[storage aspect ratio]</dt><dd><p>The ratio between the number of horizontal samples and the number of vertical samples of a two-dimensional
+representation of an image, a video frame, a viewport or region, etc.</p></dd><dt class="label"><a id="terms-synthetic-document-syncbase"></a>[synthetic document syncbase]</dt><dd><p>A document level <a href="http://www.w3.org/TR/2008/REC-SMIL3-20081201/smil30.html#smil-timing-q158">syncbase</a>
+<a href="#smil3">[SMIL 3.0]</a>, § 5.7.1, synthesized or otherwise established by
+the <a href="#terms-document-processing-context">document processing context</a> in accordance with the
+<a href="#terms-related-media-object">related media object</a> or other processing criteria.</p></dd><dt class="label"><a id="terms-synthetic-smpte-document-syncbase"></a>[synthetic smpte document syncbase]</dt><dd><p>A <a href="#terms-synthetic-document-syncbase">synthetic document syncbase</a> constructed from <a href="#terms-smpte-time-code">smpte time code</a>
+values embedded in or associated with the <a href="#terms-related-media-object">related media object</a> or
+otherwise determined by the <a href="#terms-document-processing-context">document processing context</a>.</p></dd><dt class="label"><a id="terms-temporally-active"></a>[temporally active]</dt><dd><p>A syntactic or semantic feature, e.g., an element or the presentation of an element, is
+<em>temporally active</em> when the current time of selected time base intersects with the
+active time interval of the feature.</p></dd><dt class="label"><a id="terms-temporally-active-region"></a>[temporally active region]</dt><dd><p>A <a href="#terms-region">region</a> that is <a href="#terms-temporally-active">temporally active</a>.</p></dd><dt class="label"><a id="terms-timed-text"></a>[timed text]</dt><dd><p>Textual information that is intrinsically or extrinsically
+associated with timing information.</p></dd><dt class="label"><a id="terms-timed-text-authoring-system"></a>[timed text authoring system]</dt><dd><p>A content authoring system capable of importing and exporting
+Timed Text Markup Language content.</p></dd><dt class="label"><a id="terms-timed-text-content-document"></a>[timed text content document]</dt><dd><p>An abstract document that is purported or confirmed to be a
+<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> of
+the <a href="#ttml-content-doctype">TTML Content Document Type</a>.</p></dd><dt class="label"><a id="terms-timed-text-content-document-instance"></a>[timed text content document instance]</dt><dd><p>A concrete realization of a <a href="#terms-timed-text-content-document">timed text content document</a>,
+about which see <a href="#concrete-encoding"><b>A Concrete Encoding</b></a>.</p></dd><dt class="label"><a id="terms-timed-text-document-instance"></a>[timed text document instance]</dt><dd><p>A concrete realization of a
+<a href="#terms-timed-text-markup-language-document">timed text markup language document</a>,
+where  the concrete form is specific to the context of reference.
+Also referred to as a <a href="#terms-document-instance">TTML document instance</a>
+or simply <a href="#terms-document-instance">document instance</a>.</p></dd><dt class="label"><a id="terms-timed-text-intermediate-document"></a>[timed text intermediate document]</dt><dd><p>An abstract document that is purported or confirmed to be a
+<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> of
+the <a href="#ttml-intermediate-doctype">TTML Intermediate Document Type</a>.</p></dd><dt class="label"><a id="terms-timed-text-intermediate-document-instance"></a>[timed text intermediate document instance]</dt><dd><p>A concrete realization of a <a href="#terms-timed-text-intermediate-document">timed text intermediate document</a>,
+about which see <a href="#concrete-encoding"><b>A Concrete Encoding</b></a>.</p></dd><dt class="label"><a id="terms-timed-text-markup-language"></a>[timed text markup language]</dt><dd><p>A content type that represents timed text content, intermediate representations of this content, or profiles of this content or content processors.</p></dd><dt class="label"><a id="terms-timed-text-markup-language-document"></a>[timed text markup language document]</dt><dd><p>An abstract document that is purported or confirmed to be a
+<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a>.</p></dd><dt class="label"><a id="terms-timed-text-profile-document"></a>[timed text profile document]</dt><dd><p>An abstract document that is purported or confirmed to be a
+<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> of
+the <a href="#ttml-profile-doctype">TTML Profile Document Type</a>.</p></dd><dt class="label"><a id="terms-timed-text-profile-document-instance"></a>[timed text profile document instance]</dt><dd><p>A concrete realization of a <a href="#terms-timed-text-profile-document">timed text profile document</a>,
+about which see <a href="#concrete-encoding"><b>A Concrete Encoding</b></a>.</p></dd><dt class="label"><a id="terms-top-level-profile"></a>[top-level profile]</dt><dd><p>A <a href="#terms-profile">profile</a> defined by a <code>ttp:profile</code> element that appears as a child
+of the <code>head</code> element.</p></dd><dt class="label"><a id="terms-transformation-processor"></a>[transformation processor]</dt><dd><p>A <a href="#terms-content-processor">content processor</a> which purpose is to transform or otherwise rewrite
+<a href="#terms-timed-text-markup-language">Timed Text Markup Language</a> content to either <a href="#terms-timed-text-markup-language">Timed Text Markup Language</a>
+or to another (arbitrary) content format. An example of the first is a processor that removes
+or rewrites TTML features so as to conform to a profile of TTML. An example of the latter is
+a processor that translates TTML into a completely different timed text format. Because this
+specification does not otherwise define a target profile or format for transformation processing,
+no further transformation semantics are defined by this specification.</p></dd><dt class="label"><a id="terms-undesignated-profile"></a>[undesignated profile]</dt><dd><p>A <a href="#terms-profile">profile</a> that is not associated with a <a href="#terms-profile-designator">profile designator</a>, and which is
+referred to implicitly in the context of the profile's definition. Also referred to as an <em>anonymous profile</em>.</p></dd><dt class="label"><a id="terms-valid-abstract-document-instance"></a>[valid abstract document instance]</dt><dd><p>An <a href="#terms-abstract-document-instance">abstract document instance</a> which has been assessed for validity
+and found to be valid as defined by <a href="#doctypes"><b>4 Document Types</b></a>.</p></dd><dt class="label"><a id="terms-viewport"></a>[viewport]</dt><dd><p>A logical, rectangular area with respect to which content is encoded or decoded for the purpose of presentation, where such area
+may be employed by or for the authoring or presentation of a <a href="#terms-related-media-object">related media object</a> or
+the <a href="#terms-root-container-region">root container region</a> and its constituent <a href="#terms-region">regions</a>.</p></dd><dt class="label"><a id="terms-viewport-target"></a>[viewport target]</dt><dd><p>An implied or explicit target or mapping of a <a href="#viewport">viewport</a> to some logical or physical entity, of which this
+specification identifies three such targets:
+<a href="#terms-display-target">display target</a>,
+<a href="#terms-display-region-target">display region target</a>, and
+<a href="#terms-related-media-object-region-target">related media object region target</a>.
+</p></dd></dl></div><div class="div2">
+<h3><a id="conventions"></a>2.3 Documentation Conventions</h3><p>Within normative prose in this specification, the words
+<em>may</em>, <em>should</em>, and <em>must</em> are
+defined as follows:</p><dl class="conformance-keywords"><dt class="label">may</dt><dd><p>Conforming documents and/or TTML processors are permitted to,
+but need not behave as described. </p></dd><dt class="label">should</dt><dd><p>Conforming documents and/or TTML processors are strongly
+recommended to, but need not behave as described.</p></dd><dt class="label">must</dt><dd><p>Conforming documents and/or TTML processors are required
+to behave as described; otherwise, they are in error. </p></dd></dl><p>If normative specification language takes an imperative form,
+then it is to be treated as if the term <span class="strong">must</span>
+applies. Furthermore, if normative language takes a declarative form,
+and this language is governed by <span class="strong">must</span>,
+then it is also to be treated as if the term <span class="strong">must</span>
+applies.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, the phrases "treat X as an error" and "consider X
+as an error" are to be read as mandatory requirements in the context of use. Similarly, if the specification
+prose is "X must apply", "X applies", or "X is mandatory", and "X" is further defined as "X is Y and Z",
+then, by transitive closure, this last declarative phrase is to be read as "Y is mandatory" and
+"Z is mandatory" in the context of use.</p></div><p>All normative syntactic definitions of XML representations and
+other related terms are depicted with a light yellow-orange background color
+and labeled as "XML Representation" or "Syntax Representation", such
+as in the following:</p><a id="elt-syntax-example"></a><table class="syntax"><caption>XML Representation – Element Information Item: example</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;example
+  <span class="reqattr">count</span> = <a href="http://www.w3.org/TR/xmlschema-2/#integer">xsd:integer</a>
+  size = (<em>large</em>|<em>medium</em>|<em>small</em>|<em><span class="deprecated">tiny</span></em>|<em><span class="obsoleted">micro</span></em>) : medium&gt;
+  <em>Content:</em> (all | any*)
+&lt;/example&gt;
+</pre></div>
+</td></tr></tbody></table><p>In an XML representation, bold-face attribute names (e.g. <span class="strong">count</span> above) indicate a required attribute
+information item, and the rest are optional. Where an attribute
+information item has an enumerated type definition, the values are
+shown separated by vertical bars, as for <code>size</code> above; if
+there is a default value, it is shown following a colon. Where an
+<a href="#terms-attribute-information-item">attribute information item</a> has a built-in simple type definition
+defined in <a href="#xsd-2">[XML Schema Part 2]</a>, a hyperlink to its definition
+therein is given.</p><p>In an XML representation, the expression <em>{any attribute not in default or any TT namespace}</em> applies
+only to namespace qualified attributes; unqualified attributes are not permitted unless explicitly defined in this specification.</p><p>An information item depicted with a <span class="deprecated">light yellow orange</span> background color is deprecated (e.g.,
+the <span class="deprecated">tiny</span> value of the <code>size</code> attribute shown above).
+An information item that is <span class="deprecated">deprecated</span> may but should not appear in a TTML document instance,
+and a validating processor should report a warning if it does appear.
+An information item depicted with a <span class="obsoleted">light magenta red</span> background color is obsoleted (e.g.,
+the <span class="obsoleted">micro</span> value of the <code>size</code> attribute shown above).
+An information item that is <span class="obsoleted">obsoleted</span> must not appear in a TTML document instance,
+and a validating processor should report an error if it does appear.
+These designations of an item
+are also explicitly called out in specification text.</p><p>The allowed content of the information item is shown as a grammar
+fragment, using the Kleene operators <code>?</code>, <code>*</code>
+and <code>+</code>. Each element name therein is a hyperlink to its
+own illustration.</p><p>The term linear white-space (LWSP) is to be interpreted as a non-empty sequence of
+SPACE (U+0020), TAB (U+0009), CARRIAGE RETURN (U+000D), or LINE FEED (U+000A),
+which corresponds to production [3] <code>S</code> as defined by <a href="#xml10">[XML 1.0]</a>.</p><p>All content of this specification that is not explicitly marked as
+non-normative is considered to be normative. If a section or appendix
+header contains the expression "Non-Normative", then the entirety
+of the section or appendix is considered non-normative.</p><p>All paragraphs marked as a <span class="strong">Note</span> are considered non-normative.</p><p>Example code fragments are depicted with a light blue-green
+background color and labeled as "Example Fragment", such as in
+the following:</p><a id="example-fragment-1"></a><table class="example"><caption>Example Fragment – Sample</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head&gt;
+    &lt;metadata/&gt;
+    &lt;styling/&gt;
+    &lt;layout/&gt;
+  &lt;/head&gt;
+  &lt;body/&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p>Unless specified otherwise, the vocabulary defining sections of this specification define vocabulary in alphabetical order rather than logical order.</p></div></div><div class="div1">
+<h2><a id="conformance"></a>3 Conformance</h2><p>This section specifies the general conformance requirements for
+TTML documents and processors.</p><div class="div2">
+<h3><a id="conformance-content"></a>3.1 Document Conformance</h3><p>A <a href="#terms-timed-text-document-instance">timed text document instance</a> conforms to this specification if the following criteria are
+satisfied:</p><ol class="enumar"><li><p>When transporting a <a href="#terms-document-instance">document instance</a> in a <a href="#terms-document-interchange-context">document interchange context</a> in which a
+Media Type <a href="#media-types">[MIME Media Types]</a> identifies the content type of the interchanged <a href="#terms-document-instance">document instance</a>, then the specified media type is
+<code>application/ttml+xml</code> in conformance with <a href="#xml-media">[XML Media Types]</a> § 7, with which an optional
+<code>profile</code> parameter may appear, the value of which
+conforms to
+a profile designator as
+defined by
+<a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>.</p></li><li><p>The <a href="#terms-document-instance">document instance</a> is or can be represented as a <a href="#terms-reduced-xml-infoset">reduced xml infoset</a>
+as defined by <a href="#reduced-infoset"><b>B Reduced XML Infoset</b></a>.</p></li><li><p>The <a href="#terms-reduced-xml-infoset">reduced xml infoset</a> that
+corresponds to the <a href="#terms-document-instance">document instance</a> is or can
+be associated with one of the <a href="#terms-abstract-document-type">abstract document types</a> defined by
+<a href="#doctypes"><b>4 Document Types</b></a>.</p></li><li><p>The <a href="#terms-reduced-xml-infoset">reduced xml infoset</a> that corresponds to the <a href="#terms-document-instance">document instance</a> is a
+<a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> of the associated
+<a href="#terms-abstract-document-type">abstract document type</a>.</p></li><li><p>The <a href="#terms-reduced-xml-infoset">reduced xml infoset</a> satisfies all additional mandatory syntactic and
+semantic constraints defined by this specification. In addition, this infoset
+should satisfy the web content accessibility guidelines specified by
+<a href="#wcag">[WCAG]</a>.</p></li></ol></div><div class="div2">
+<h3><a id="conformance-processor"></a>3.2 Processor Conformance</h3><div class="div3">
+<h4><a id="conformance-generic-processor"></a>3.2.1 Generic Processor Conformance</h4><table border="1" class="ednote" summary="Editorial note: Profile Processing"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Profile Processing</b></td><td align="right" valign="top">2014-05-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add requirement to invoke <span class="strong">abort if unsupported processor profile</span> procedure.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Validation Processing"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Validation Processing</b></td><td align="right" valign="top">2014-05-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add requirement to invoke validation processing procedure. Add and use definition of 'validating processor'.</td></tr></table><p>A TTML <a href="#terms-content-processor">content processor</a> conforms to this specification if the following
+generic processor criteria are
+satisfied:</p><ol class="enumar"><li><p>The processor provides at least one mechanism for notionally
+instantiating a <a href="#terms-reduced-xml-infoset">reduced xml infoset</a>
+representation of a conformant <a href="#terms-document-instance">document instance</a>.</p></li><li><p>If a processor does or can perform validation of a candidate 
+<a href="#terms-document-instance">document instance</a>, then it provides at least one mechanism to
+implicitly or explicitly associate the
+<a href="#terms-reduced-xml-infoset">reduced xml infoset</a> representation
+of a conformant <a href="#terms-document-instance">document instance</a> with one of the
+<em>Abstract Document Types</em> defined by
+<a href="#doctypes"><b>4 Document Types</b></a>.</p></li><li><p>The processor does not <em>a priori</em> reject or abort the
+processing of a conformant <a href="#terms-document-instance">document instance</a>
+unless the processor does not support some required
+(mandatory) feature specified or implied by a TTML profile
+declared to apply to the <a href="#terms-document-instance">document instance</a>.</p></li><li><p>The processor supports all mandatory processing semantics defined by this specification.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The phrase <em>mandatory semantics</em> refers to all explicit use of the conformance
+key phrases <span class="strong">must</span> and <span class="strong">must not</span> as well as any
+declarative statement that can be reasonably inferred from such key phrases. For example, these
+mandatory semantics include support for all features marked as mandatory in <a href="#feature-support"><b>E.2 Feature Support</b></a>.</p></div></li><li><p>If the processor supports some optional processing semantics defined by this specification,
+then it does so in a manner consistent with the defined semantics.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The phrase <em>optional semantics</em> refers to all explicit use of the conformance
+key phrases <span class="strong">should</span>, <span class="strong">should not</span>,
+<span class="strong">may</span>, and <span class="strong">may not</span>,
+as well as any declarative statement that can be reasonably inferred from such key phrases. For example, these
+optional semantics include support for all features marked as optional in <a href="#feature-support"><b>E.2 Feature Support</b></a>.</p></div></li></ol></div><div class="div3">
+<h4><a id="conformance-transformation-processor"></a>3.2.2 Transformation Processor Conformance</h4><p>A TTML <a href="#terms-content-processor">content processor</a> is a conformant TTML <a href="#terms-transformation-processor">transformation processor</a> if
+the following criteria are satisfied:</p><ol class="enumar"><li><p>The processor satisfies all requirements specified by
+<a href="#conformance-generic-processor"><b>3.2.1 Generic Processor Conformance</b></a>.</p></li><li><p>The processor supports the TTML Transformation profile as specified
+by <a href="#profile-ttml2-transformation"><b>G.3 TTML2 Transformation Profile</b></a>.</p></li></ol><table border="1" class="ednote" summary="Editorial note: Mandatory Support for DFXP Transformation Profile"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Mandatory Support for DFXP Transformation Profile</b></td><td align="right" valign="top">2014-07-31</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Should we also require support for DFXP Transformation Profile?</td></tr></table></div><div class="div3">
+<h4><a id="conformance-presentation-processor"></a>3.2.3 Presentation Processor Conformance</h4><p>A TTML <a href="#terms-content-processor">content processor</a> is a conformant TTML <a href="#terms-presentation-processor">presentation processor</a> if
+the following criteria are satisfied:</p><ol class="enumar"><li><p>The processor satisfies all requirements specified by
+<a href="#conformance-generic-processor"><b>3.2.1 Generic Processor Conformance</b></a>.</p></li><li><p>The processor supports the TTML Presentation profile as specified
+by <a href="#profile-ttml2-presentation"><b>G.2 TTML2 Presentation Profile</b></a>.</p></li></ol><table border="1" class="ednote" summary="Editorial note: Mandatory Support for DFXP Presentation Profile"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Mandatory Support for DFXP Presentation Profile</b></td><td align="right" valign="top">2014-07-31</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Should we also require support for DFXP Presentation Profile?</td></tr></table></div></div><div class="div2">
+<h3><a id="claims"></a>3.3 Claims</h3><p>Any claim of compliance with respect to the conformance of a TTML <a href="#terms-document-instance">document instance</a> or
+<a href="#terms-content-processor">content processor</a> must make
+reference to an implementation compliance statement (ICS).</p><p>An implementation compliance statement must identify all mandatory
+and optional features of this specification that are satisfied by the
+document instance or the content processor implementation. In particular, the statement must
+identify the utilized or supported TTML vocabulary profile(s) as
+defined by <a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>, and, if a subset or
+superset profile is used or supported, then what features are excluded
+or included in the subset or superset profile.</p><p>A <a href="#terms-document-instance">document instance</a> for which a compliance claim is made
+must specify
+either (1)
+a <code>ttp:profile</code> attribute on its root
+<code>tt</code>
+element
+as defined by <a href="#profile-attribute-profile"><b>6.2.7 ttp:profile</b></a>
+or (2)
+a <code>ttp:profile</code> element as a child of the
+<code>head</code> element as defined by
+<a href="#profile-vocabulary-profile"><b>6.1.1 ttp:profile</b></a>. In addition, it must specify a
+<code>ttp:version</code> attribute on its root <code>tt</code> element if it requires
+support for a <a href="#terms-feature">feature</a> not defined by <a href="#ttml1">[TTML1]</a>.</p></div></div><div class="div1">
+<h2><a id="doctypes"></a>4 Document Types</h2><p>This section defines the following TTML <em>Abstract Document Types</em>:</p><ul><li><p><a href="#ttml-content-doctype"><b>4.1 TTML Content Document Type</b></a></p></li><li><p><a href="#ttml-intermediate-doctype"><b>4.2 TTML Intermediate Document Type</b></a></p></li><li><p><a href="#ttml-profile-doctype"><b>4.3 TTML Profile Document Type</b></a></p></li></ul><p>Each <a href="#terms-abstract-document-type">abstract document type</a> consists of the following constraints:</p><ul><li><p>a non-empty collection of element types, where each element type consists of a name,
+a (possibly empty) collection of attributes, and a content specification</p></li><li><p>a non-empty collection of element types that may appear as the document element</p></li></ul><p>An <a href="#terms-abstract-document-instance">abstract document instance</a> may be assessed in terms of validity,
+and is considered to be a <a href="#terms-valid-abstract-document-instance">valid abstract document instance</a> if it
+satisfies the following condition: if after</p><ol class="enumar"><li><p>pruning all element information
+items whose names are not members of the collection of element types defined
+by the associated <a href="#terms-abstract-document-type">abstract document type</a>, then</p></li><li><p>pruning character
+information item children from any remaining element in case that all
+character children of the element denote XML whitespace characters and the element's type
+is defined as empty in the associated <a href="#terms-abstract-document-type">abstract document type</a>, and then</p></li><li><p>pruning all attribute
+information items having expanded names such that the namespace URI of the
+expanded names are not listed in <a href="#namespace-vocab-table"><b>Table 5-1 – Namespaces</b></a>,</p></li></ol><p>then the document element is one of the document
+element types permitted by the associated <a href="#terms-abstract-document-type">abstract document type</a>,
+the descendants of the document
+element satisfy their respective element type's content
+specifications, all required attributes are present, and the declared
+value of each attribute satisfies the type declared by the
+associated <a href="#terms-abstract-document-type">abstract document type</a>.</p><div class="issue"><p class="prefix"><a id="issue-362"></a><b>Issue (issue-362):</b></p><p class="prefix"><b>Attribute Forward Compabitility</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/362">http://www.w3.org/AudioVideo/TT/tracker/issues/362</a></p><p>Enhance step (3) to handle forward compatibility of new attributes introduced into TT namespaces.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>While a conformant processor may not <em>a priori</em> reject a
+conformant <a href="#terms-document-instance">document instance</a>, a given <a href="#terms-document-instance">document instance</a> may be
+constrained by the author or authoring tool to satisfy a more
+restrictive definition of validity.</p></div><div class="div2">
+<h3><a id="ttml-content-doctype"></a>4.1 TTML Content Document Type</h3><p>The TTML Content Document Type is an <a href="#terms-abstract-document-type">abstract document type</a> of a profile
+of the Timed Text Markup Language intended to be used for interchange among distribution systems. This document type
+is defined in terms of the element and attribute vocabulary specified in <a href="#vocabulary"><b>5 Vocabulary</b></a>.</p><p>This specification references two types of schemas that may be used to validate a superset/subset
+of <a href="#terms-timed-text-content-document-instance">timed text content document instances</a>:</p><ul><li><p><a href="#ttml-schema-rnc"><b>C.1 Relax NG Compact (RNC) Schema</b></a></p></li><li><p><a href="#ttml-schema-xsd"><b>C.2 XML Schema Definition (XSD) Schema</b></a></p></li></ul><p>The (root) document element of a TTML Content <a href="#terms-document-instance">document instance</a> must be a
+<code>tt</code> element, as defined by <a href="#document-structure-vocabulary-tt"><b>8.1.1 tt</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The schemas referenced by this specification do not validate all syntactic constraints
+defined by this specification, and, as such, represent a superset of conformant
+TTML Content. In particular, performing validation with one of the above
+referenced schemas may result in a <em>false positive</em> indication of validity.
+For example, both the RNC and XSD schemas specify
+that a <code>tts:fontFamily</code> attribute must
+satisfy the <code>xsd:string</code> XSD data type; however, this data type is a superset
+of the values permitted to be used with the <code>tts:fontFamily</code> attribute.</p><p>In addition, the RNC schema may produce a <em>false negative</em>
+indication of validity when using the <code>xml:id</code> attribute with an element in
+a foreign namespace, thus representing a subset of conformant TTML Content. This is
+due to a specific limitation in expressing wildcard patterns involving <code>xsd:ID</code>
+typed attributes in Relax NG schemas. Note that this specification defines the
+formal validity of a <a href="#terms-document-instance">document instance</a> to be based on an <a href="#terms-abstract-document-instance">abstract document instance</a> from
+which all foreign namespace elements and attributes have been removed. Therefore, the
+exceptional reporting of this false negative does not impact the formal assessment
+of <a href="#terms-document-instance">document instance</a> validity.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>A conforming <a href="#conformance-generic-processor">Generic Processor</a> is required to support the ingestion and processing
+of a <a href="#terms-timed-text-content-document">timed text content document</a>.</p></div></div><div class="div2">
+<h3><a id="ttml-intermediate-doctype"></a>4.2 TTML Intermediate Document Type</h3><p>The TTML Intermediate Document Type is an <a href="#terms-abstract-document-type">abstract document type</a> intended
+to be used to represent the content of a
+<a href="#terms-timed-text-content-document">timed text content document</a>
+in such a manner that all discrete animation, styling, and timing information is denoted in
+a non-hierarchical (flat), temporally linear manner. This document type is defined in terms of the element and attribute vocabulary
+specified in <a href="#isd"><b>I Intermediate Document Syntax</b></a> and <a href="#vocabulary"><b>5 Vocabulary</b></a>.</p><p>This specification references two types of schemas that may be used to validate
+<a href="#terms-timed-text-intermediate-document-instance">timed text intermediate document instances</a>:</p><ul><li><p><a href="#ttml-schema-rnc"><b>C.1 Relax NG Compact (RNC) Schema</b></a></p></li><li><p><a href="#ttml-schema-xsd"><b>C.2 XML Schema Definition (XSD) Schema</b></a></p></li></ul><p>The (root) document element of a TTML Intermediate Synchronic <a href="#terms-document-instance">document instance</a> must be an
+<code>isd:sequence</code> or <code>isd:isd</code> element, as defined by <a href="#isd"><b>I Intermediate Document Syntax</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A conforming <a href="#conformance-generic-processor">Generic Processor</a> is not required to support the ingestion or processing
+of a <a href="#terms-timed-text-intermediate-document">timed text intermediate document</a>.</p></div></div><div class="div2">
+<h3><a id="ttml-profile-doctype"></a>4.3 TTML Profile Document Type</h3><p>The TTML Profile Document Type is an <a href="#terms-abstract-document-type">abstract document type</a> intended
+to be used for defining and communicating constraints on the support or use of TTML features or extensions. This document type
+is defined in terms of the element and attribute vocabulary specified in <a href="#vocabulary"><b>5 Vocabulary</b></a>.</p><p>This specification references two types of schemas that may be used to validate
+<a href="#terms-timed-text-profile-document-instance">timed text profile document instances</a>:</p><ul><li><p><a href="#ttml-schema-rnc"><b>C.1 Relax NG Compact (RNC) Schema</b></a></p></li><li><p><a href="#ttml-schema-xsd"><b>C.2 XML Schema Definition (XSD) Schema</b></a></p></li></ul><p>The (root) document element of a TTML Profile <a href="#terms-document-instance">document instance</a> must be a
+<code>ttp:profile</code> element, as defined by <a href="#profile-vocabulary-profile"><b>6.1.1 ttp:profile</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A conforming <a href="#conformance-generic-processor">Generic Processor</a> is recommended, but not required to support the ingestion or processing
+of a <a href="#terms-timed-text-profile-document">timed text profile document</a>. However, a <a href="#terms-content-processor">content processor</a>
+that claims to support the <code>http://www.w3.org/ns/ttml/feature/#profile</code> feature is required to support this (ingestion and processing of
+a <a href="#terms-timed-text-profile-document">timed text profile document</a>).</p></div></div></div><div class="div1">
+<h2><a id="vocabulary"></a>5 Vocabulary</h2><p>This section defines the
+namespaces, profiles, and vocabulary (as an element and attribute
+catalog) of the Timed Text Markup Language (TTML) as follows:</p><ul><li><p><a href="#vocabulary-namespaces"><b>5.1 Namespaces</b></a></p></li><li><p><a href="#vocabulary-profiling"><b>5.2 Profiling</b></a></p></li><li><p><a href="#vocabulary-overview"><b>5.3 Catalog</b></a></p></li></ul><div class="div2">
+<h3><a id="vocabulary-namespaces"></a>5.1 Namespaces</h3><p>The Timed Text Markup Language (TTML) employs a number of
+XML Namespaces <a href="#xmlns10">[XML Namespaces 1.0]</a> for elements and certain
+global attributes. The following table specifies this set of namespaces
+and indicates the default prefix used within this specification and the
+normative URI that denotes each namespace.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In a specific <a href="#terms-document-instance">document instance</a>, it is not required that the default
+prefixes shown below are used. Any prefix or namespace binding that satisfies the constraints
+of XML Namespaces <a href="#xmlns10">[XML Namespaces 1.0]</a>  may be used that is associated with the specified namespace URI.</p></div><a id="namespace-vocab-table"></a><table class="common"><caption>Table 5-1 – Namespaces</caption><col width="30%" span="1"><col span="1"><col span="1"><tbody><tr><th>Name</th><th>Prefix</th><th>Value</th></tr><tr><td>TT</td><td><code>tt:</code></td><td><code>http://www.w3.org/ns/ttml</code></td></tr><tr><td>TT Parameter</td><td><code>ttp:</code></td><td><code>http://www.w3.org/ns/ttml#parameter</code></td></tr><tr><td>TT Style</td><td><code>tts:</code></td><td><code>http://www.w3.org/ns/ttml#styling</code></td></tr><tr><td>TT Metadata</td><td><code>ttm:</code></td><td><code>http://www.w3.org/ns/ttml#metadata</code></td></tr><tr><td>TT Intermediate Synchronic Document</td><td><code>isd:</code></td><td><code>http://www.w3.org/ns/ttml#isd</code></td></tr><tr><td>TT Profile</td><td><em>none</em></td><td><code>http://www.w3.org/ns/ttml/profile/</code></td></tr><tr><td>TT Feature</td><td><em>none</em></td><td><code>http://www.w3.org/ns/ttml/feature/</code></td></tr><tr><td>TT Extension</td><td><em>none</em></td><td><code>http://www.w3.org/ns/ttml/extension/</code></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>If a reference to an element type is used in this specification and the name
+of the element type is not namespace qualified, then the TT Namespace applies.</p><p>If a reference to an attribute is used in this specification and the name
+of the attribute is not namespace qualified, then the attribute is implicitly qualified by
+the element type with which it is used. That is, the attribute resides in the so-called
+<a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/#ns-breakdown"><em>per-element-type namespace partition</em></a>
+<a href="#nsoriginal">[NSOriginal]</a>, the members of which are interpreted in accordance with the definition of the element type on which they appear.</p><p>For certain namespaces defined above, the default prefix
+is specified as <em>none</em> if no XML vocabulary is defined in
+the namespace by this specification (nor expected to be defined in a
+future version of this specification). In such cases, the use of the
+namespace URI is for purposes other than defining XML vocabulary,
+e.g., for designating profiles, features, extensions and for
+dereferencing standard profile definitions.</p></div><p>All TTML Namespaces are <a href="http://www.w3.org/2001/tag/doc/namespaceState#namespacedef"><em>mutable</em></a>
+<a href="#nsstate">[NSState]</a>; all undefined names in these namespaces are reserved for future
+standardization by the W3C.</p></div><div class="div2">
+<h3><a id="vocabulary-profiling"></a>5.2 Profiling</h3><p>This section describes the TTML profiling sub-system and high level requirements that apply to this sub-system. At the end of this section
+appears a sub-section containing examples of profile specifications and examples of how these specifications are referenced and used.</p><div class="div3">
+<h4><a id="vocabulary-profile-introduction"></a>5.2.1 Introduction</h4><p><em>This sub-section is non-normative.</em></p><p>A given profile may be used by a Timed Text Markup Language content author for one of two functions: (1) to declare that a
+<a href="#terms-document-instance">document instance</a> adheres to a collection of constraints on what
+vocabulary is used and how it is used, or (2) to declare that a <a href="#terms-processor">processor</a> must satisfy certain conditions on how
+content is processed. The first of these functions is termed a <a href="#terms-content-profile">content profile</a>, while
+the second is termed a <a href="#terms-processor-profile">processor profile</a>.</p><p>A <a href="#terms-content-profile">content profile</a> is used to allow an author to declare, at authoring time,
+what constraints the author intends to apply to a <a href="#terms-document-instance">document instance</a>. Such a
+declaration permits downstream processors to perform content validation or verification, as well as to guide or limit subsequent
+transformation or editing of content in order to maintain adherence to an author specified content profile. In addition, a
+downstream processor may use a content profile declaration to perform an early determination of its ability to process the features
+implied by the content profile.</p><p>Content profiles are declared by using (1) the <a href="#parameter-attribute-contentProfiles"><code>ttp:contentProfiles</code></a>
+attribute on the root <code>tt</code> element, (2) one or more top-level <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a>
+elements of type <code>content</code>, or (3) a combination of these two mechanisms. If not declared, no content profile is implied.</p><p>A <a href="#terms-processor-profile">processor profile</a> is used to allow an author to declare, at authoring time,
+what processing must be supported when processing a <a href="#terms-document-instance">document instance</a>, such that, if a
+processor is not able to perform the indicated processing, then processing should be aborted. Such a declaration permits downstream
+processors to avoid processing content that cannot be processed in a manner that meets the requirements of the content author.</p><p>Processor profiles are declared by using (1) the <a href="#parameter-attribute-processorProfiles"><code>ttp:processorProfiles</code></a>
+attribute on the root <code>tt</code> element, (2) one or more <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a>
+elements of type <code>processor</code>, or (3) a combination of these two mechanisms.
+If not declared, a processor profile is inferred from a declared content profile or from a
+<a href="#terms-default-profile">default profile</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>It is not a requirement on a conformant <a href="#terms-document-instance">document instance</a> that a processor profile be internally
+declared by use of a <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element or internally referenced by a
+<a href="#parameter-attribute-processorProfiles"><code>ttp:processorProfiles</code></a> attribute. More specifically, it is
+permitted that the <a href="#terms-document-interchange-context">document
+interchange context</a> determines the applicable processor profile through private
+agreement, out-of-band protocol, or common use (between sender and receiver) of a processor profile defined
+by an external specification.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>It is intended that the <code>ttp:processorProfiles</code> attribute be used when
+the author wishes to reference one (or more) of the standard, predefined processor profiles of
+TTML Content, and does not wish to modify (by supersetting or subsetting)
+that profile. This attribute may also be used by an author to indicate the use
+of a non-standard profile, in which case the specified profile designator expresses
+a URI that denotes an externally defined <a href="#terms-profile-definition-document">profile definition document</a>.
+However, it is not required that a conformant TTML <a href="#terms-content-processor">content processor</a> be able
+to dereference such an externally specified profile definition.</p><p>In contrast, it is intended that the <code>ttp:profile</code> element be
+used when the author wishes to make use of a modified predefined profile or
+wishes to include in the <a href="#terms-document-instance">document instance</a> a non-standard profile definition
+not based upon one of the predefined profiles.</p><p>A predefined profile is supersetted by specifying some feature or extension to
+be <code>required</code> (mandatory) that was either not specified in the underlying, baseline
+profile or was specified as <code>optional</code> (voluntary) in the baseline profile.
+A predefined profile is subsetted by specifying some feature or extension to
+be <code>optional</code> (voluntary) that was specified as <code>required</code> (mandatory)
+in the underlying, baseline profile.</p><p>When a baseline profile is modified by subsetting, the resulting, derived profile
+is referred to as a <em>subtractive</em> profile; when modified by supersetting, the result
+is referred to as an <em>additive</em> profile.
+It is also possible to define a derived profile that is simultaneously subtractive
+and additive.</p></div><p>A content author is not limited to using a single profile, but may make reference to multiple profiles of either type, i.e.,
+multiple content profiles and/or multiple processor profiles. When multiple profiles are referenced, their respective specifications
+are combined to form a single effective content profile that applies to the document and a single effective processor profile
+that applies to a processor when processing the document. In addition, an author is not limited to making reference to externally
+defined profiles, but may define one or more profiles inline within a document.</p></div><div class="div3">
+<h4><a id="semantics-profile-examples"></a>5.2.2 Profile Examples</h4><p><em>This sub-section is non-normative.</em></p><table border="1" class="ednote" summary="Editorial note: More profile examples."><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: More profile examples.</b></td><td align="right" valign="top">2014-05-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add more examples depicting new profiling features defined in TTML2.</td></tr></table><p>An example of an author defined
+additive, derived profile of the TTML Presentation
+profile is shown
+below in <a href="#ttml-example-sub-profile"><b>Example Fragment – TTML Additive Profile</b></a>.</p><a id="ttml-example-sub-profile"></a><table class="example"><caption>Example Fragment – TTML Additive Profile</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+ &lt;head&gt;
+   &lt;profile use="ttml2-presentation" xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
+     &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+       &lt;feature value="required"&gt;#fontStyle-italic&lt;/feature&gt;
+     &lt;/features&gt;
+   &lt;/profile&gt;
+ &lt;/head&gt;
+ &lt;body/&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the baseline profile is declared to be
+the TTML Presentation profile, which is then additively modified by making the
+<code>#fontStyle-italic</code> feature required (rather than
+optional as it is defined
+in <a href="#profile-ttml2-presentation"><b>G.2 TTML2 Presentation Profile</b></a>). Note also the resetting of the
+default XMLNS binding on the <code>profile</code> element to the TT Parameter Namespace.</p></div></div><div class="div3">
+<h4><a id="vocabulary-profile-designators"></a>5.2.3 Profile Designators</h4><table border="1" class="ednote" summary="Editorial note: Reference by designator to internally defined profile."><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Reference by designator to internally defined profile.</b></td><td align="right" valign="top">2014-05-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Handle case where a designator refers to an internally defined profile.</td></tr></table><p>A profile is referenced in one of two ways according to whether the profile is defined externally to the referring document or
+is defined inline within the referring document. When defined externally, a profile is referenced by means of a
+<a href="#terms-profile-designator">profile designator</a>. When defined internally (inline), a profile is referenced either implicitly
+or by means of <a href="#terms-profile-fragment-identifier">profile fragment identifier</a>.</p><table border="1" class="ednote" summary="Editorial note: Profile Fragment Identifiers."><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Profile Fragment Identifiers.</b></td><td align="right" valign="top">2014-05-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Update following to account for use of profile fragment identifier as a profile designator.</td></tr></table><p>A profile designator must adhere to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17. If the profile designator is expressed as a relative URI,
+then it must be absolutized by using the TT Profile Namespace value as
+the base URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, if a profile designator is expressed as
+<code>ttml2-presentation</code>, then the absolutized profile designator
+would be
+<code>http://www.w3.org/ns/ttml/profile/ttml2-presentation</code>.</p></div><p>All profile designators which have the TT Profile Namespace as a prefix but are otherwise not listed in
+<a href="#profile-vocab-table"><b>Table 5-2 – Profiles</b></a> are reserved for future standardization, and must not appear in a conformant
+<a href="#terms-document-instance">document instance</a>. Nothwithstanding this constraint, a profile designator is not restricted to the set of designators enumerated
+in <a href="#profile-vocab-table"><b>Table 5-2 – Profiles</b></a>, but may be any URI that feasibly dereferences a TTML <a href="#terms-profile-definition-document">profile definition document</a>
+provided it does not use the TT Profile Namespace as a prefix.</p><div class="div4">
+<h5><a id="vocabulary-profile-standard-designators"></a>5.2.3.1 Standard Designators</h5><p>The Timed Text Markup Language (TTML) employs a number of
+standard, predefined profiles of its
+vocabulary and associated semantics.</p><p>The following table specifies this set of
+profiles, indicating
+a normative name
+and designator for each
+predefined profile,
+and where each of these profiles is formally elaborated in
+<a href="#standard-profiles"><b>G Standard Profiles</b></a>, in <a href="#ttml1">[TTML1]</a>,
+or in another TTWG specification.</p><a id="profile-vocab-table"></a><table class="common"><caption>Table 5-2 – Profiles</caption><col width="25%" span="1"><col span="1"><tbody><tr><th>Name</th><th>Designator</th></tr><tr><td>DFXP Full</td><td><code>http://www.w3.org/ns/ttml/profile/dfxp-full</code></td></tr><tr><td>DFXP Presentation</td><td><code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code></td></tr><tr><td>DFXP Transformation</td><td><code>http://www.w3.org/ns/ttml/profile/dfxp-transformation</code></td></tr><tr><td>SDP US</td><td><code>http://www.w3.org/ns/ttml/profile/sdp-us</code></td></tr><tr><td>TTML2 Full</td><td><code>http://www.w3.org/ns/ttml/profile/ttml2-full</code></td></tr><tr><td>TTML2 Presentation</td><td><code>http://www.w3.org/ns/ttml/profile/ttml2-presentation</code></td></tr><tr><td>TTML2 Transformation</td><td><code>http://www.w3.org/ns/ttml/profile/ttml2-transformation</code></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>For definitions of the DFXP profiles, see <a href="#ttml1">[TTML1]</a>. For definition of the SDP US profile, see <a href="#sdpus">[SDP US]</a>.</p></div></div></div><div class="div3">
+<h4><a id="semantics-profile-semantics"></a>5.2.4 Profile Semantics</h4><div class="div4">
+<h5><a id="semantics-profile-state"></a>5.2.4.1 Profile State Object Concepts</h5><p>This section defines a number of conceptual state objects used by subsequently defined algorithms (procedures and functions). It is not required that an
+implementation create such objects in the form specified here, but may use any convenient, internal representation that represents equivalent information.</p><dl><dt class="label"><a id="semantics-profile-state-profile-specification"></a>[profile specification]</dt><dd><p>a <a href="#semantics-profile-state-profile-specification"><span class="strong">profile specification</span></a>
+represents the following internal state information that corresponds with
+a <a href="#profile-vocabulary-feature"><code>ttp:feature</code></a> or <a href="#profile-vocabulary-extension"><code>ttp:extension</code></a>
+element</p><dl><dt class="label"><a id="semantics-profile-state-profile-specification-designator"></a>designator</dt><dd><p>an absolute xsd:anyURI denoting a feature or extension designator depending upon the <em><code>type</code></em></p></dd><dt class="label"><a id="semantics-profile-state-profile-specification-type"></a>type</dt><dd><p><code>feature|extension</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-specification-value"></a>value</dt><dd><p><code>optional|required|prohibited</code></p></dd></dl></dd><dt class="label"><a id="semantics-profile-state-combined-profile-specification-set"></a>[combined profile specification set]</dt><dd><p>a <a href="#semantics-profile-state-combined-profile-specification-set"><span class="strong">combined profile specification set</span></a>
+represents the following internal state information
+that corresponds with a set of <a href="#semantics-profile-state-profile-specification"><span class="strong">profile specifications</span></a>,
+additionally recording the constituent
+profiles from which these specifications were obtained (or derived)</p><dl><dt class="label"><a id="semantics-profile-state-combined-profile-specification-set-constituents"></a>constituents</dt><dd><p>ordered list of absolute profile designators, where each designator denotes a constituent profile, i.e.,
+a profile from which this combined profile specification set is composed</p></dd><dt class="label"><a id="semantics-profile-state-combined-profile-specification-set-specifications"></a>specifications</dt><dd><p>ordered list of <a href="#semantics-profile-state-profile-specification"><span class="strong">profile specifications</span></a></p></dd></dl></dd><dt class="label"><a id="semantics-profile-state-empty-profile-specification-set"></a>[empty profile specification set]</dt><dd><p>a <a href="#semantics-profile-state-combined-profile-specification-set"><span class="strong">combined profile specification set</span></a> which 
+<a href="#semantics-profile-state-combined-profile-specification-set-constituents"><span class="strong">constituents</span></a> and
+<a href="#semantics-profile-state-combined-profile-specification-set-specifications"><span class="strong">specifications</span></a> fields are empty sets</p></dd><dt class="label"><a id="semantics-profile-state-profile"></a>[profile]</dt><dd><p>a <a href="#semantics-profile-state-profile"><span class="strong">profile</span></a> represents the following internal state information
+that corresponds with a <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element, whether specified explicitly or implied</p><dl><dt class="label"><a id="semantics-profile-state-profile-designator"></a>designator</dt><dd><p>an absolute profile designator that is associated with (and uniquely labels) this profile</p></dd><dt class="label"><a id="semantics-profile-state-profile-type"></a>type</dt><dd><p><code>content|processor</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-combine"></a>combine</dt><dd><p><code>leastRestrictive|mostRestrictive|replace</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-use"></a>use</dt><dd><p>either <code>null</code> or an absolute profile designator denoting a profile that serves as the baseline profile for this profile</p></dd><dt class="label"><a id="semantics-profile-state-profile-constituents"></a>constituents</dt><dd><p>if profile is a <a href="#terms-nesting-profile">nesting profile</a>, then an ordered list of absolute profile designators, where each designator denotes a
+constituent <a href="#terms-nested-profile">nested profile</a>; otherwise, <code>null</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-specifications"></a>specifications</dt><dd><p>if profile is a <a href="#terms-non-nesting-profile">non-nesting profile</a>, then an ordered list of
+<a href="#semantics-profile-state-profile-specification"><span class="strong">profile specifications</span></a>; otherwise, <code>null</code></p></dd><dt class="label"><a id="semantics-profile-state-profile-combined-specification-set"></a>combined specification set</dt><dd><p>a <a href="#semantics-profile-state-combined-profile-specification-set"><span class="strong">combined profile specification set</span></a> that
+represents the results of combining the specifications specified or referenced by this profile</p></dd></dl></dd></dl></div><div class="div4">
+<h5><a id="semantics-content-profile-processing"></a>5.2.4.2 Content Profile Semantics</h5><table border="1" class="ednote" summary="Editorial note: Validation Processing"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Validation Processing</b></td><td align="right" valign="top">2014-05-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add validation processing procedures.</td></tr></table><dl><dt class="label"><a id="semantics-procedure-construct-effective-content-profile"></a>[construct effective content profile]</dt><dd><p>Every TTML <a href="#terms-document-instance">document instance</a> is associated with an
+<a href="#terms-effective-content-profile">effective content profile</a> which may be used by
+a <a href="#terms-content-processor">content processor</a> to perform any (or all) of the following:</p><ol class="enumar"><li><p>infer an effective processor profile;</p></li><li><p>perform validation processing on the <a href="#terms-document-instance">document instance</a>;</p></li><li><p>constrain transformation processing on the <a href="#terms-document-instance">document instance</a>
+in order to maintain content profile invariants.</p></li></ol><p>The <a href="#terms-effective-content-profile">effective content profile</a> is determined according to the
+<a href="#semantics-procedure-construct-effective-content-profile"><span class="strong">construct effective content profile</span></a> procedure
+defined as follows:</p><ol class="enumar"><li><p>if a <code>ttp:contentProfiles</code> attribute is specified on the root <code>tt</code> element, then</p><ol class="enumla"><li><p>if the <code>ttp:contentProfiles</code> attribute is specified using the <code>all(...)</code> function syntax or
+using no function syntax, i.e., as only a list of designators, then the
+<a href="#terms-effective-content-profile">effective content profile</a> is the combined profile specification set
+produced by combining the combined profile specification sets of the designated profiles, where the <code>mostRestrictive</code>
+content profile combination method applies;</p></li><li><p>otherwise, if the <code>ttp:contentProfiles</code> attribute is specified using the <code>any(...)</code> function syntax, then the
+<a href="#terms-effective-content-profile">effective content profile</a> is the combined profile specification set
+produced by combining the combined profile specification sets of the designated profiles, where the <code>leastRestrictive</code>
+content profile combination method applies;</p></li></ol></li><li><p>otherwise, if one or more <a href="#terms-top-level-profile">top-level</a> <a href="#terms-content-profile">content profiles</a>
+are defined, then the
+<a href="#terms-effective-content-profile">effective content profile</a> is the combined profile specification set
+produced by combining the combined profile specification sets of all such
+<a href="#terms-top-level-profile">top-level</a> <a href="#terms-content-profile">content profiles</a>, where the
+content profile combination method specified by (or the default value of) the <code>ttp:contentProfileCombination</code>
+attribute on the root <code>tt</code> element applies;
+</p></li><li><p>otherwise, the <a href="#terms-effective-content-profile">effective content profile</a> is <code>null</code>;</p></li></ol></dd></dl></div><div class="div4">
+<h5><a id="semantics-processor-profile-processing"></a>5.2.4.3 Processor Profile Semantics</h5><dl><dt class="label"><a id="semantics-procedure-abort-if-unsupported-processor-profile"></a>[abort if unsupported processor profile]</dt><dd><ol class="enumar"><li><p>set <em>EPP</em> to the <a href="#terms-effective-processor-profile">effective processor profile</a> obtained by performing the
+<a href="#semantics-procedure-construct-effective-processor-profile"><span class="strong">construct effective processor profile</span></a> procedure;</p></li><li><p>for each profile specification <em>S</em> in the combined profile specification set of <em>EPP</em>, perform the following steps:</p><ol class="enumla"><li><p>if the <span class="strong">value</span> field of <em>S</em> is <code>required</code>, and the <a href="#terms-content-processor">content processor</a>
+does not support <em>S</em>, then abort processing of the <a href="#terms-document-instance">document instance</a> unless overridden
+by the end-user or some implementation specific parameter traceable to an end-user or to a user or system configuration setting;</p></li></ol></li></ol></dd><dt class="label"><a id="semantics-procedure-construct-effective-processor-profile"></a>[construct effective processor profile]</dt><dd><p>Every TTML <a href="#terms-document-instance">document instance</a> is associated with an
+<a href="#terms-effective-processor-profile">effective processor profile</a> which is used by
+a <a href="#terms-content-processor">content processor</a> to determine whether it meets the
+minimum processing requirements signaled by the content author, and if not, then must abort further
+processing unless overridden by the end-user or an implementation specific parameter traceable to
+an end-user or to a user or system configuration setting.
+The <a href="#terms-effective-processor-profile">effective processor profile</a> is determined according to the
+<a href="#semantics-procedure-construct-effective-processor-profile"><span class="strong">construct effective processor profile</span></a> procedure
+defined as follows:</p><ol class="enumar"><li><p>if a <code>ttp:processorProfiles</code> attribute is specified on the root <code>tt</code> element, then</p><ol class="enumla"><li><p>if the <code>ttp:processorProfiles</code> attribute is specified using the <code>all(...)</code> function syntax or
+using no function syntax, i.e., as only a list of designators, then the
+<a href="#terms-effective-processor-profile">effective processor profile</a> is the combined profile specification set
+produced by combining the combined profile specification sets of the designated profiles, where the <code>mostRestrictive</code>
+processor profile combination method applies;</p></li><li><p>otherwise, if the <code>ttp:processorProfiles</code> attribute is specified using the <code>any(...)</code> function syntax,
+then, for each designated profile, the 
+<a href="#terms-effective-processor-profile">effective processor profile</a> is the combined profile specification set
+of the first profile in the list of designated profiles that is supported by the
+<a href="#terms-content-processor">content processor</a>;</p></li></ol></li><li><p>otherwise, if one or more <a href="#terms-top-level-profile">top-level</a> <a href="#terms-processor-profile">processor profiles</a>
+are defined, then the
+<a href="#terms-effective-processor-profile">effective processor profile</a> is the combined profile specification set
+produced by combining the combined profile specification sets of all such
+<a href="#terms-top-level-profile">top-level</a> <a href="#terms-processor-profile">processor profiles</a>, where the
+processor profile combination method specified by (or the default value of) the <code>ttp:processorProfileCombination</code>
+attribute on the root <code>tt</code> element applies;
+</p></li><li><p>otherwise, if a <code>ttp:profile</code> attribute is specified on the root <code>tt</code> element, then the
+<a href="#terms-effective-processor-profile">effective processor profile</a> is the combined profile specification set
+of the profile designated by this attribute;
+</p></li><li><p>otherwise, the <a href="#terms-effective-processor-profile">effective processor profile</a> is the
+result of performing the <a href="#semantics-procedure-construct-inferred-processor-profile"><span class="strong">construct inferred processor profile</span></a>
+procedure;</p></li></ol></dd><dt class="label"><a id="semantics-procedure-construct-inferred-processor-profile"></a>[construct inferred processor profile]</dt><dd><ol class="enumar"><li><p>set <em>ECP</em> to the <a href="#terms-effective-content-profile">effective content profile</a>;</p></li><li><p>if <em>ECP</em> is not <code>null</code>, then perform the following steps:</p><ol class="enumla"><li><p>if the computed value of the <code>ttp:inferProcessorProfileSource</code> parameter is <code>combine</code>, then
+the <a href="#terms-inferred-processor-profile">inferred processor profile</a> is the result of applying the
+<a href="#semantics-procedure-infer-processor-profile"><span class="strong">infer processor profile</span></a> function
+to the combined profile specification set of <em>ECP</em>;</p></li><li><p>otherwise, if the computed value of the <code>ttp:inferProcessorProfileSource</code> parameter is <code>first</code>, then
+the <a href="#terms-inferred-processor-profile">inferred processor profile</a> is the first inferred processor profile, <em>IPP</em>, produced by applying the
+<a href="#semantics-procedure-infer-processor-profile"><span class="strong">infer processor profile</span></a> function
+to the combined profile specification set of each constituent of <em>ECP</em> such that
+<em>IPP</em> is supported by the <a href="#terms-content-processor">content processor</a>;</p></li></ol></li><li><p>otherwise, the <a href="#terms-inferred-processor-profile">inferred processor profile</a> is the
+result of performing the <a href="#semantics-procedure-construct-default-processor-profile"><span class="strong">construct default processor profile</span></a>
+procedure;</p></li></ol></dd><dt class="label"><a id="semantics-procedure-infer-processor-profile"></a>[infer processor profile](content profile <em>CP</em>)</dt><dd><ol class="enumar"><li><p>initialize inferred processor profile <em>IPP</em> to the empty combined profile specification set;</p></li><li><p>for each profile specification, <em>S</em>, in the combined profile specification set of content profile <em>CP</em>:</p><ol class="enumla"><li><p>map content profile specification <em>S</em> to processor profile specification <em>S'&nbsp;</em> according to the computed
+value of the <code>ttp:inferPresentationProfileMethod</code> parameter and <a href="#infer-processor-profile-method-table"><b>Table 6-2 – Infer Processor Profile Method</b></a>;</p></li><li><p>add <em>S'&nbsp;</em> to the combined profile specification set of <em>IPP</em>;</p></li></ol></li><li><p>return <em>IPP</em> as the inferred processor profile;</p></li></ol></dd><dt class="label"><a id="semantics-procedure-construct-default-processor-profile"></a>[construct default processor profile]</dt><dd><ol class="enumar"><li><p>if the <a href="#terms-document-interchange-context">document interchange context</a> is associated with a
+<a href="#terms-processor-profile">processor profile</a> or with a <a href="#terms-content-profile">content profile</a>
+from which a <a href="#terms-processor-profile">processor profile</a> can be inferred, then the
+<a href="#terms-default-processor-profile">default processor profile</a> is that <a href="#terms-processor-profile">processor profile</a>;</p></li><li><p>otherwise, if the <a href="#terms-content-processor">content processor</a> is primarily characterized as a
+<a href="#terms-presentation-processor">presentation processor</a>, then:</p><ol class="enumla"><li><p>if the <a href="#parameter-attribute-version"><code>ttp:version</code></a> attribute is not specified on the root <code>tt</code> element or
+if the computed value of its parameter property is <code>1</code> (one), then the <a href="#terms-default-processor-profile">default processor profile</a> is
+the <a href="#semantics-profile-state-profile">profile</a> constructed by interning the DFXP Presentation profile
+(<code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code>);</p></li><li><p>otherwise,
+if the computed value of the <a href="#parameter-attribute-version"><code>ttp:version</code></a> parameter property is <code>2</code> (two),
+the <a href="#terms-default-processor-profile">default processor profile</a> is
+the <a href="#semantics-profile-state-profile">profile</a> constructed by interning the TTML2 Presentation profile
+(<code>http://www.w3.org/ns/ttml/profile/ttml2-presentation</code>);</p></li><li><p>otherwise,
+the <a href="#terms-default-processor-profile">default processor profile</a> is
+the <a href="#semantics-profile-state-profile">profile</a> constructed by interning a TTML presentation profile
+associated with the computed value of <a href="#parameter-attribute-version"><code>ttp:version</code></a>,
+if one is known, or, if not known, then the most recently defined presentation profile;</p></li></ol></li><li><p>otherwise, if the <a href="#terms-content-processor">content processor</a> is primarily characterized as a
+<a href="#terms-transformation-processor">transformation processor</a>, then:</p><ol class="enumla"><li><p>if the <a href="#parameter-attribute-version"><code>ttp:version</code></a> attribute is not specified on the root <code>tt</code> element or
+if the computed value of its parameter property is <code>1</code> (one), then the <a href="#terms-default-processor-profile">default processor profile</a> is
+the <a href="#semantics-profile-state-profile">profile</a> constructed by interning the DFXP Transformation profile
+(<code>http://www.w3.org/ns/ttml/profile/dfxp-transformation</code>);</p></li><li><p>otherwise,
+if the computed value of the <a href="#parameter-attribute-version"><code>ttp:version</code></a> parameter property is <code>2</code> (two),
+the <a href="#terms-default-processor-profile">default processor profile</a> is
+the <a href="#semantics-profile-state-profile">profile</a> constructed by interning the TTML2 Transformation profile
+(<code>http://www.w3.org/ns/ttml/profile/ttml2-transformation</code>);</p></li><li><p>otherwise,
+the <a href="#terms-default-processor-profile">default processor profile</a> is
+the <a href="#semantics-profile-state-profile">profile</a> constructed by interning a TTML transformation profile
+associated with the computed value of <a href="#parameter-attribute-version"><code>ttp:version</code></a>,
+if one is known, or, if not known, then the most recently defined TTML transformation profile;</p></li></ol></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>A <a href="#terms-content-processor">content processor</a> intended to be used with
+one or more distinct versions of TTML greater than version 2 (TTML2) may choose a
+<a href="#terms-default-processor-profile">default processor profile</a> based upon
+a future version of a TTML presentation or transformation profile.</p></div></dd></dl></div></div></div><div class="div2">
+<h3><a id="vocabulary-overview"></a>5.3 Catalog</h3><p>The vocabulary of the Timed Text Markup Language (TTML) is
+defined in the following major catalogs (divisions of vocabulary):</p><ul><li><p><a href="#core-vocabulary-overview"><b>5.3.1 Core Catalog</b></a></p></li><li><p><a href="#extension-vocabulary-overview"><b>5.3.2 Extension Catalog</b></a></p></li></ul><p>The core catalog defines the baseline, core vocabulary of TTML,
+and, in particular, the vocabulary of TTML Content. The extension catalog
+serves as a placeholder for extensions to the core vocabulary defined
+by TTML.</p><div class="div3">
+<h4><a id="core-vocabulary-overview"></a>5.3.1 Core Catalog</h4><p>The core vocabulary catalog is intended to satisfy the needs of
+TTML while providing a baseline vocabulary for future profiles. This vocabulary
+is divided into distinct categories, specified in detail
+in the following sections:</p><ul><li><p><a href="#profile"><b>6 Profile</b></a></p></li><li><p><a href="#parameter"><b>7 Parameter</b></a></p></li><li><p><a href="#content"><b>8 Content</b></a></p></li><li><p><a href="#embedded-content"><b>9 Embedded Content</b></a></p></li><li><p><a href="#styling"><b>10 Styling</b></a></p></li><li><p><a href="#layout"><b>11 Layout</b></a></p></li><li><p><a href="#timing"><b>12 Timing</b></a></p></li><li><p><a href="#animation"><b>13 Animation</b></a></p></li><li><p><a href="#metadata"><b>14 Metadata</b></a></p></li></ul><p>The core element vocabulary specified for use with a <a href="#terms-document-instance">document instance</a> is enumerated in
+<a href="#element-vocab-table"><b>Table 5-3 – Element Vocabulary</b></a>.</p><a id="element-vocab-table"></a><table class="common"><caption>Table 5-3 – Element Vocabulary</caption><col width="25%" span="1"><col span="1"><tbody><tr><th>Module</th><th>Elements</th></tr><tr id="element-vocab-type-animation"><td>
+Animation
+</td><td>
+<a href="#animation-vocabulary-animate">animate</a>,
+<a href="#animation-vocabulary-animation">animation</a>,
+<a href="#animation-vocabulary-set">set</a>
+</td></tr><tr id="element-vocab-type-audio"><td>
+Audio
+</td><td>
+<a href="#data-vocabulary-audio">audio</a>
+</td></tr><tr id="element-vocab-type-content"><td>
+Content
+</td><td>
+<a href="#document-structure-vocabulary-body">body</a>,
+<a href="#content-vocabulary-br">br</a>,
+<a href="#content-vocabulary-div">div</a>,
+<a href="#content-vocabulary-p">p</a>,
+<a href="#content-vocabulary-span">span</a>
+</td></tr><tr id="element-vocab-type-data"><td>
+Data
+</td><td>
+<a href="#data-vocabulary-data">chunk</a>,
+<a href="#data-vocabulary-data">data</a>,
+<a href="#data-vocabulary-resources">resources</a>,
+<a href="#data-vocabulary-source">source</a>
+</td></tr><tr id="element-vocab-type-document"><td>
+Document
+</td><td>
+<a href="#document-structure-vocabulary-tt">tt</a>
+</td></tr><tr id="element-vocab-type-font"><td>
+Font
+</td><td>
+<a href="#data-vocabulary-font">font</a>
+</td></tr><tr id="element-vocab-type-head"><td>
+Head
+</td><td>
+<a href="#document-structure-vocabulary-head">head</a>
+</td></tr><tr id="element-vocab-type-image"><td>
+Image
+</td><td>
+<a href="#data-vocabulary-image">image</a>
+</td></tr><tr id="element-vocab-type-layout"><td>
+Layout
+</td><td>
+<a href="#layout-vocabulary-layout">layout</a>,
+<a href="#layout-vocabulary-region">region</a>
+</td></tr><tr id="element-vocab-type-metadata"><td>
+Metadata
+</td><td>
+<a href="#metadata-vocabulary-metadata">metadata</a>
+</td></tr><tr id="element-vocab-type-metadata-items"><td>
+Metadata Items
+</td><td>
+<a href="#metadata-vocabulary-actor">ttm:actor</a>,
+<a href="#metadata-vocabulary-agent">ttm:agent</a>,
+<a href="#metadata-vocabulary-copyright">ttm:copyright</a>,
+<a href="#metadata-vocabulary-desc">ttm:desc</a>,
+<a href="#metadata-vocabulary-item">ttm:item</a>,
+<a href="#metadata-vocabulary-name">ttm:name</a>,
+<a href="#metadata-vocabulary-title">ttm:title</a>
+</td></tr><tr id="element-vocab-type-profile"><td>Profile</td><td>
+<a href="#profile-vocabulary-features">ttp:features</a>,
+<a href="#profile-vocabulary-feature">ttp:feature</a>,
+<a href="#profile-vocabulary-extensions">ttp:extensions</a>,
+<a href="#profile-vocabulary-extension">ttp:extension</a>,
+<a href="#profile-vocabulary-profile">ttp:profile</a>
+</td></tr><tr id="element-vocab-type-styling"><td>
+Styling
+</td><td>
+<a href="#styling-vocabulary-initial">initial</a>,
+<a href="#styling-vocabulary-styling">styling</a>,
+<a href="#styling-vocabulary-style">style</a>
+</td></tr></tbody></table><p></p><p>Element vocabulary groups that are used in defining content models
+for TTML element types are enumerated in <a href="#element-vocab-group-table"><b>Table 5-4 – Element Vocabulary Groups</b></a>.</p><a id="element-vocab-group-table"></a><table class="common"><caption>Table 5-4 – Element Vocabulary Groups</caption><col width="25%" span="1"><col span="1"><tbody><tr><th>Group</th><th>Elements</th></tr><tr id="element-vocab-group-animation"><td>
+Animation.class
+</td><td>
+<a href="#animation-vocabulary-animate">animate</a> |
+<a href="#animation-vocabulary-set">set</a>
+</td></tr><tr id="element-vocab-group-block"><td>
+Block.class
+</td><td>
+<a href="#content-vocabulary-div">div</a> |
+<a href="#content-vocabulary-p">p</a>
+</td></tr><tr id="element-vocab-group-data"><td>
+Data.class
+</td><td>
+<a href="#data-vocabulary-data">data</a>
+</td></tr><tr id="element-vocab-group-embedded"><td>
+Embedded.class
+</td><td>
+<a href="#data-vocabulary-audio">audio</a>,
+<a href="#data-vocabulary-image">image</a>
+</td></tr><tr id="element-vocab-group-font"><td>
+Font.class
+</td><td>
+<a href="#data-vocabulary-font">font</a>
+</td></tr><tr id="element-vocab-group-inline"><td>
+Inline.class
+</td><td>
+<a href="#content-vocabulary-span">span</a> |
+<a href="#content-vocabulary-span">br</a> |
+<code>#PCDATA</code>
+</td></tr><tr><td>
+Layout.class
+</td><td id="element-vocab-group-layout">
+<a href="#layout-vocabulary-region">region</a>
+</td></tr><tr id="element-vocab-group-metadata"><td>
+Metadata.class
+</td><td>
+<a href="#metadata-vocabulary-metadata">metadata</a> |
+<a href="#metadata-vocabulary-copyright">ttm:agent</a> |
+<a href="#metadata-vocabulary-copyright">ttm:copyright</a> |
+<a href="#metadata-vocabulary-desc">ttm:desc</a> |
+<a href="#metadata-vocabulary-desc">ttm:item</a> |
+<a href="#metadata-vocabulary-title">ttm:title</a>
+</td></tr><tr id="element-vocab-group-profile"><td>Profile.class</td><td><a href="#profile-vocabulary-profile">ttp:profile</a></td></tr></tbody></table><p></p><p>The attribute vocabulary specified for use with the core vocabulary
+catalog is enumerated in
+<a href="#attribute-vocab-table"><b>Table 5-5 – Attribute Vocabulary</b></a>.</p><a id="attribute-vocab-table"></a><table class="common"><caption>Table 5-5 – Attribute Vocabulary</caption><col width="25%" span="1"><col span="1"><tbody><tr><th>Module</th><th>Attributes</th></tr><tr id="attribute-vocab-group-animation-binding"><td>
+Animation Binding Attribute
+</td><td>
+<a href="#animation-attribute-animate">animate</a>
+</td></tr><tr id="attribute-vocab-group-core"><td>
+Core Attributes
+</td><td>
+<a href="#content-attribute-xml-id">xml:id</a>,
+<a href="#content-attribute-xml-lang">xml:lang</a>,
+<a href="#content-attribute-xml-space">xml:space</a>
+</td></tr><tr id="attribute-vocab-group-data"><td>
+Data Attributes
+</td><td>
+<a href="#embedded-content-attribute-encoding">encoding</a>,
+<a href="#embedded-content-attribute-format">format</a>,
+<a href="#embedded-content-attribute-src">src</a>,
+<a href="#embedded-content-attribute-type">type</a>
+</td></tr><tr id="attribute-vocab-group-layout-binding"><td>
+Layout Binding Attribute
+</td><td>
+<a href="#layout-attribute-region">region</a>
+</td></tr><tr id="attribute-vocab-group-metadata"><td>
+Metadata Attributes
+</td><td>
+<a href="#metadata-attribute-agent">ttm:agent</a>,
+<a href="#metadata-attribute-role">ttm:role</a>
+</td></tr><tr id="attribute-vocab-group-parameters"><td>
+Parameter Attributes
+</td><td>
+<a href="#parameter-attribute-cellResolution">ttp:cellResolution</a>,
+<a href="#parameter-attribute-clockMode">ttp:clockMode</a>,
+<a href="#parameter-attribute-dropMode">ttp:dropMode</a>,
+<a href="#parameter-attribute-frameRate">ttp:frameRate</a>,
+<a href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultipler</a>,
+<a href="#parameter-attribute-markerMode">ttp:markerMode</a>,
+<a href="#parameter-attribute-mediaDuration">ttp:mediaDuration</a>,
+<a href="#parameter-attribute-mediaOffset">ttp:mediaOffset</a>,
+<a href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</a>,
+<a href="#parameter-attribute-storageAspectRatio">ttp:storageAspectRatio</a>,
+<a href="#parameter-attribute-subFrameRate">ttp:subFrameRate</a>,
+<a href="#parameter-attribute-tickRate">ttp:tickRate</a>,
+<a href="#parameter-attribute-timeBase">ttp:timeBase</a>,
+</td></tr><tr id="attribute-vocab-group-profile"><td>
+Profile Attributes
+</td><td>
+<a href="#profile-attribute-contentProfiles">ttp:contentProfiles</a>,
+<a href="#profile-attribute-contentProfileCombination">ttp:contentProfileCombination</a>,
+<a href="#profile-attribute-inferProcessorProfileMethod">ttp:inferProcessorProfileMethod</a>,
+<a href="#profile-attribute-inferProcessorProfileSource">ttp:inferProcessorProfileSource</a>,
+<a href="#profile-attribute-permitFeatureNarrowing">ttp:permitFeatureNarrowing</a>,
+<a href="#profile-attribute-permitFeatureWidening">ttp:permitFeatureWidening</a>,
+<a href="#profile-attribute-profile">ttp:profile</a>,
+<a href="#profile-attribute-processorProfiles">ttp:processorProfiles</a>,
+<a href="#profile-attribute-processorProfileCombination">ttp:processorProfileCombination</a>,
+<a href="#profile-attribute-validation">ttp:validation</a>,
+<a href="#profile-attribute-validationAction">ttp:validationAction</a>,
+<a href="#profile-attribute-version">ttp:version</a>
+</td></tr><tr id="attribute-vocab-group-style-binding"><td>
+Style Binding Attribute
+</td><td>
+<a href="#style-attribute-style">style</a>
+</td></tr><tr id="attribute-vocab-group-style"><td>
+Styling Attributes
+</td><td>
+<a href="#style-attribute-backgroundColor">tts:backgroundColor</a>,
+<a href="#style-attribute-backgroundImage">tts:backgroundImage</a>,
+<a href="#style-attribute-backgroundPosition">tts:backgroundPosition</a>,
+<a href="#style-attribute-backgroundRepeat">tts:backgroundRepeat</a>,
+<a href="#style-attribute-border">tts:border</a>,
+<a href="#style-attribute-color">tts:color</a>,
+<a href="#style-attribute-direction">tts:direction</a>,
+<a href="#style-attribute-display">tts:display</a>,
+<a href="#style-attribute-displayAlign">tts:displayAlign</a>,
+<a href="#style-attribute-extent">tts:extent</a>,
+<a href="#style-attribute-fontFamily">tts:fontFamily</a>,
+<a href="#style-attribute-fontKerning">tts:fontKerning</a>,
+<a href="#style-attribute-fontSelectionStrategy">tts:fontSelectionStrategy</a>,
+<a href="#style-attribute-fontShear">tts:fontShear</a>,
+<a href="#style-attribute-fontSize">tts:fontSize</a>,
+<a href="#style-attribute-fontStyle">tts:fontStyle</a>,
+<a href="#style-attribute-fontVariantPosition">tts:fontVariantPosition</a>,
+<a href="#style-attribute-fontWeight">tts:fontWeight</a>,
+<a href="#style-attribute-height">tts:height</a>,
+<a href="#style-attribute-letterSpacing">tts:letterSpacing</a>,
+<a href="#style-attribute-lineHeight">tts:lineHeight</a>,
+<a href="#style-attribute-opacity">tts:opacity</a>,
+<a href="#style-attribute-origin">tts:origin</a>,
+<a href="#style-attribute-overflow">tts:overflow</a>,
+<a href="#style-attribute-padding">tts:padding</a>,
+<a href="#style-attribute-position">tts:position</a>,
+<a href="#style-attribute-ruby">tts:ruby</a>,
+<a href="#style-attribute-rubyAlign">tts:rubyAlign</a>,
+<a href="#style-attribute-rubyOffset">tts:rubyOffset</a>,
+<a href="#style-attribute-rubyPosition">tts:rubyPosition</a>,
+<a href="#style-attribute-showBackground">tts:showBackground</a>,
+<a href="#style-attribute-textAlign">tts:textAlign</a>,
+<a href="#style-attribute-textCombine">tts:textCombine</a>,
+<a href="#style-attribute-textDecoration">tts:textDecoration</a>,
+<a href="#style-attribute-textEmphasis">tts:textEmphasis</a>,
+<a href="#style-attribute-textOrientation">tts:textOrientation</a>,
+<a href="#style-attribute-textOutline">tts:textOutline</a>,
+<a href="#style-attribute-textShadow">tts:textShadow</a>,
+<a href="#style-attribute-unicodeBidi">tts:unicodeBidi</a>,
+<a href="#style-attribute-visibility">tts:visibility</a>,
+<a href="#style-attribute-width">tts:width</a>,
+<a href="#style-attribute-wrapOption">tts:wrapOption</a>,
+<a href="#style-attribute-writingMode">tts:writingMode</a>,
+<a href="#style-attribute-zIndex">tts:zIndex</a>
+</td></tr><tr id="attribute-vocab-group-timing"><td>
+Timing Attributes
+</td><td>
+<a href="#timing-attribute-begin">begin</a>,
+<a href="#timing-attribute-dur">dur</a>,
+<a href="#timing-attribute-end">end</a>,
+<a href="#timing-attribute-timeContainer">timeContainer</a>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>Only those attributes defined as either (1) global, i.e., namespace qualified, or
+(2) shared element-specific, i.e., not namespace qualified but shared across multiple
+element types, are listed in <a href="#attribute-vocab-table"><b>Table 5-5 – Attribute Vocabulary</b></a> above.
+</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>All vocabulary defined by TTML consistently makes use of
+the so-called <em>lowerCamelCase</em> naming convention. In some cases, this results in the
+change of a name when the name was based upon another specification
+that used a different naming convention.</p></div></div><div class="div3">
+<h4><a id="extension-vocabulary-overview"></a>5.3.2 Extension Catalog</h4><p>The extension vocabulary catalog is intended for use by future
+profiles of TTML, and is not further defined
+by this version of this specification.</p><p>In addition to standardized extension vocabulary, a conforming 
+<a href="#terms-document-instance">document instance</a> may contain arbitrary namespace qualified
+elements that reside in any namespace other than those namespaces
+defined for use with this specification. Furthermore, a conforming 
+<a href="#terms-document-instance">document instance</a> may contain arbitrary namespace qualified
+attributes on TTML defined vocabulary where such attributes reside in
+any namespace other than those defined for use with this
+specification.</p></div></div></div><div class="div1">
+<h2><a id="profile"></a>6 Profile</h2><p>This section specifies the <em>profile</em> matter of the
+core vocabulary catalog, where profile matter is to be understood as information that expresses requirements or optionality related to authoring or processing
+a <a href="#terms-timed-text-content-document">timed text content document</a>.</p><div class="div2">
+<h3><a id="profile-element-vocabulary"></a>6.1 Profile Element Vocabulary</h3><p>The following elements, all defined in the TT Parameter
+Namespace, specify parametric information that applies to a <a href="#terms-document-instance">document instance</a>
+or <a href="#terms-content-processor">content processor</a>:</p><ul><li><p><a href="#profile-vocabulary-profile"><b>6.1.1 ttp:profile</b></a></p></li><li><p><a href="#profile-vocabulary-features"><b>6.1.2 ttp:features</b></a></p></li><li><p><a href="#profile-vocabulary-feature"><b>6.1.3 ttp:feature</b></a></p></li><li><p><a href="#profile-vocabulary-extensions"><b>6.1.4 ttp:extensions</b></a></p></li><li><p><a href="#profile-vocabulary-extension"><b>6.1.5 ttp:extension</b></a></p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>The sub-sections of this section are ordered logically (from highest to lowest level construct).</p></div><div class="div3">
+<h4><a id="profile-vocabulary-profile"></a>6.1.1 ttp:profile</h4><p>The <code>ttp:profile</code> element is used to specify a
+<a href="#terms-processor-profile">processor profile</a> or a
+<a href="#terms-content-profile">content profile</a>.
+A <a href="#terms-processor-profile">processor profile</a> specifies a
+collection of required (mandatory) and optional (voluntary) features and extensions that must or
+may be supported by a <a href="#terms-content-processor">content processor</a> in order to process a
+<a href="#terms-document-instance">document instance</a> that makes (or may make) use of such features and
+extensions.
+A <a href="#terms-content-profile">content profile</a> specifies a
+collection of prohibited, required, and optional features and extensions that, respectively,
+must not, must, and may be present in a <a href="#terms-document-instance">document instance</a> that declares its
+adherence to the profile.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The difference between a <em>feature</em> and an
+<em>extension</em> is where it is defined and how it is labeled:
+if defined in this specification (or a future revision thereof) and
+labeled with a feature designation in <a href="#features"><b>E Features</b></a>, then
+it is considered to be a feature; if defined in another specification
+and labeled there with an extension designation, then it is considered
+to be an extension. In general, features are expected to be defined by
+the W3C standards process, while extensions are expected to be defined by
+third parties.</p></div><p>This specification defines two distinct contexts of use for the <code>ttp:profile</code> element:</p><ul><li><p>as a child of the <code>head</code> element or a <code>ttp:profile</code> element within a TTML <a href="#terms-document-instance">document instance</a>;</p></li><li><p>as the root element of a TTML <a href="#terms-profile-definition-document">profile definition document</a>
+instance;</p></li></ul><p>When a <code>ttp:profile</code> element appears within a TTML <a href="#terms-document-instance">document instance</a>,
+its purpose is to express authorial intentions about (1) which
+features and extensions must or may be supported by a recipient
+content processor in order to process that document or (2) which features and extensions must not, must, or may be
+included or otherwise used in that <a href="#terms-document-instance">document instance</a>.</p><p>When a <code>ttp:profile</code> element is used by a TTML <a href="#terms-profile-definition-document">profile definition document</a> instance,
+it serves to publish a machine
+readable specification of a specific TTML profile that may be referenced by TTML <a href="#terms-document-instance">document instances</a>.
+This specification defines a number of standard <em>Profile Definition Documents</em> in
+<a href="#standard-profiles"><b>G Standard Profiles</b></a>.</p><p>The <code>ttp:profile</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by either (1)
+zero or more <code>ttp:features</code> elements followed by
+zero or more <code>ttp:extensions</code> elements or (2)
+zero or more <code>ttp:profile</code> elements.
+When a <code>ttp:profile</code> element contains a child <code>ttp:profile</code> element, then the child is referred to as
+a <a href="#terms-nested-profile">nested profile</a> and the parent is referred to as a <a href="#terms-nesting-profile">nesting profile</a>;
+otherwise it is referred to as a <a href="#terms-non-nesting-profile">non-nesting profile</a>.</p><a id="elt-syntax-profile"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:profile</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttp:profile
+  combine = (leastRestrictive|mostRestrictive|replace) : replace
+  designator = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  type = (processor|content) : processor
+  use = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, ((<a href="#profile-vocabulary-features">ttp:features</a>*, <a href="#profile-vocabulary-extensions">ttp:extensions</a>*)|<a href="#profile-vocabulary-profile">ttp:profile</a>*)
+&lt;/ttp:profile&gt;
+</pre></div>
+</td></tr></tbody></table><p>The <code>type</code> attribute is used to determine whether a profile is a
+<a href="#terms-processor-profile">processor profile</a> or a
+<a href="#terms-content-profile">content profile</a>. If not specified,
+the profile is considered to be a <a href="#terms-processor-profile">processor profile</a>.
+If a <code>ttp:profile</code> element references a <a href="#terms-baseline-profile">baseline profile</a> or a
+<a href="#terms-nested-profile">nested profile</a>, then the type of the referenced profile must be the same as the type of the referencing profile. For
+example, a <code>ttp:profile</code> element that defines a <a href="#terms-processor-profile">processor profile</a> may only make reference to other
+<a href="#terms-processor-profile">processor profiles</a>, and may not reference a <a href="#terms-content-profile">content profile</a>.</p><p>The <code>combine</code> attribute is used to specify how
+feature or extension specifications are combined in the case that
+multiple specifications apply to the same feature or extension, respectively.</p><p>If the value of the <code>combine</code> attribute is <code>replace</code>, then a
+lexically subsequent feature or extension specification replaces a lexically prior
+specification, where specification elements are ordered as follows:</p><ol class="enumar"><li><p>specifications defined by a <a href="#terms-baseline-profile">baseline profile</a> referenced by a <code>use</code>
+attribute;</p></li><li><p>specifications defined by descendant <code>ttp:profile</code> elements in post-order
+traversal order;</p></li><li><p>specifications defined as descendant <code>ttp:feature</code> or <code>ttp:extension</code>
+elements in post-order traversal order.</p></li></ol><p>If the value is <code>leastRestrictive</code>, then the least restrictive specification value applies;
+if the value is <code>mostRestrictive</code>, then the most restrictive specification value
+applies. The order of restrictiveness is as follows (from least to most):
+<em>optional</em>, <em>required</em>, <em>prohibited</em>.</p><p>If the <code>combine</code> attribute is not specified, then replacement semantics apply.</p><p>If specified, the <code>designator</code> attribute must (1) adhere to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17 and (2) express an absolute URI that denotes a profile designator in
+accordance with <a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>. A <code>designator</code> attribute may
+be specified on a <code>ttp:profile</code> element that appears in a TTML
+<a href="#terms-document-instance">document instance</a>, and, if not specified,
+the defined profile is considered to be an undesignated profile.
+A <code>designator</code> attribute should
+be specified on a <code>ttp:profile</code> element that appears in a TTML
+<a href="#terms-profile-definition-document">profile definition document</a> instance,
+and, if not specified, the defining context (e.g., an external specification) must specify
+a designator in its accompanying definition text.</p><p>If specified, the <code>use</code> attribute must adhere to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17, and, furthermore, must denote a profile designator in
+accordance with <a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>. In this case,
+the profile designator must refer to (1) a standard, predefined
+<a href="#terms-profile-definition-document">profile definition document</a> as defined by <a href="#profile"><b>6 Profile</b></a>,
+or (2) a feasibly dereferenceable resource representing a valid <em>Profile Definition
+Document</em> instance. In either case, the referenced profile serves as the
+<a href="#terms-baseline-profile">baseline profile</a> of the specifying <code>ttp:profile</code> element.</p><p>If the <code>use</code> attribute is not specified, then the <a href="#terms-baseline-profile">baseline profile</a>
+of the <code>ttp:profile</code> element must be considered to be
+the empty (null) profile, i.e., a profile definition containing no
+feature or extension specifications.</p><p>The combined specification set <em>CSS</em> of features and extensions of a profile <em>P</em>
+is determined according to the following ordered rules, where merging a specification <em>S</em>
+into <em>CSS</em> entails applying a combination method in accordance with the specified
+(or default) value of the <code>combine</code> attribute, and where merging a combined specification set <em>CSS'&nbsp;</em> into
+<em>CSS</em> entails merging each ordered specification of <em>CSS'&nbsp;</em> into <em>CSS</em>:</p><ol class="enumar"><li><p>initialize <em>CSS</em> to the empty set;</p></li><li><p>if a <code>use</code> attribute is present, then merge
+the combined specification set of the referenced <a href="#terms-baseline-profile">baseline profile</a> into <em>CSS</em>;</p></li><li><p>for each <code>ttp:profile</code> child of the <em>P</em>,
+using a post-order traversal, merge the combined specification set of the child profile
+into <em>CSS</em>;</p></li><li><p>for each <code>ttp:feature</code> and <code>ttp:extension</code> child of the <code>ttp:profile</code> element,
+using a post-order traversal, merge the feature or extension specification
+into <em>CSS</em>.</p></li></ol><p>A conformant TTML processor is not required to be able to
+dereference a <a href="#terms-profile-definition-document">profile definition document</a> that is not one of the
+standard, predefined profiles defined by <a href="#standard-profiles"><b>G Standard Profiles</b></a>.  Furthermore,
+a conformant TTML processor may make use of a built-in, static
+form of each standard, predefined profile so as not to require
+dereferencing a network resource.</p><p>If a TTML processor is unable to dereference a non-standard
+<a href="#terms-profile-definition-document">profile definition document</a>, then it must not further process the
+document without the presence of an explicit override from an end-user
+or some implementation specific parameter traceable to an end-user or
+to a user or system configuration setting. If a TTML processor aborts
+processing of a <a href="#terms-document-instance">document instance</a> due to the inability to
+reference a non-standard <a href="#terms-profile-definition-document">profile definition document</a>, then some
+end-user notification should be given unless the end-user or system
+has disabled such a notification, or if the processor does not permit
+or entail the intervention of an end-user.</p><p>The <code>ttp:profile</code> element is illustrated by the following example.</p><a id="profile-vocabulary-profile-example-1"></a><table class="example"><caption>Example Fragment – ttp:profile</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttp:profile use="ttml2-presentation"&gt;
+  &lt;ttp:features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+    &lt;ttp:feature&gt;#text-outline&lt;/ttp:feature&gt;
+  &lt;/ttp:features&gt;
+&lt;/ttp:profile&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the TTML presentation profile is used as the
+baseline profile. This baseline profile is then supersetted (thus
+creating an additive derived profile) by requiring support for
+<code>#text-outline</code> feature.</p></div></div><div class="div3">
+<h4><a id="profile-vocabulary-features"></a>6.1.2 ttp:features</h4><p>The <code>ttp:features</code> element is a container element used to group
+infomation about feature support and usage requirements.</p><p>The <code>ttp:features</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by
+zero or more <code>ttp:feature</code> elements.</p><a id="elt-syntax-features"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:features</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttp:features
+  xml:base = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a> : <em>TT Feature Namespace</em>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#profile-vocabulary-feature">ttp:feature</a>*
+&lt;/ttp:features&gt;
+</pre></div>
+</td></tr></tbody></table><p>If specified, the <code>xml:base</code>
+attribute must (1) adhere to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17, (2) express an absolute URI that
+adheres to <a href="#xmlbase">[XML Base]</a> and,
+(3) express a feature namespace as defined by
+<a href="#feature-designations"><b>E.1 Feature Designations</b></a>. If not specified, the
+<code>xml:base</code> attribute's default
+value applies, which is the TT Feature Namespace.</p><p>The <code>xml:base</code> attribute is
+used to permit the abbreviation of feature designation URIs expressed
+by child <code>ttp:feature</code> elements.</p></div><div class="div3">
+<h4><a id="profile-vocabulary-feature"></a>6.1.3 ttp:feature</h4><p>The <code>ttp:feature</code> element is used to specify
+infomation about support and usage requirements for a particular feature.</p><a id="elt-syntax-feature"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:feature</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttp:feature
+  extends = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  restricts = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  value = (optional|required|<span class="obsoleted">use</span>|prohibited) : <em>see prose below</em>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA
+&lt;/ttp:feature&gt;
+</pre></div>
+</td></tr></tbody></table><p>The children of the <code>ttp:feature</code> element must express a non-empty
+sequence of <a href="#terms-character-information-item">character information items</a> the concatenation of which adheres to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17.</p><p>If specified, the <code>extends</code> attribute and/or the <code>restricts</code>
+attribute must (1) adhere to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17, and
+(2) express a feature designation as defined by
+<a href="#feature-designations"><b>E.1 Feature Designations</b></a>.</p><p>The <code>extends</code> attribute may be used to indicate that the feature being defined
+is, from either (or both) a syntactic or (and) semantic perspective, a proper superset of the
+feature referenced by the <code>extends</code> attribute.
+The <code>restricts</code> attribute may be used to indicate that the feature being defined
+is, from either (or both) a syntactic or (and) semantic perspective, a proper subset of the
+feature referenced by the <code>restricts</code> attribute.
+If an <code>extends</code> attribute is specified, then a <code>restricts</code> attribute must
+not be specified on a <code>ttp:feature</code> element; likewise, if a <code>restricts</code> attribute
+is specified, then an <code>extends</code> attribute must not be specified.</p><p>If the URI expressed by (1) the content of the <code>ttp:feature</code>
+element, (2) the <code>extends</code> attribute, or (3) the <code>restricts</code> attribute
+is a relative URI, then, when combined with the
+feature namespace value expressed by the
+<code>xml:base</code> attribute of the
+nearest ancestor <code>ttp:features</code> element, it must express an
+absolute URI.  In either case (original absolute URI or resulting
+absolutized URI), the URI expressed by the <code>ttp:feature</code>
+element must further adhere to the syntax of a feature designation as
+defined by <a href="#feature-designations"><b>E.1 Feature Designations</b></a>, and, furthermore,
+the specific designation that appears in this URI, i.e., the portion of the feature designation
+that starts with the fragment identifier separator '#', must
+be defined by this specification or some published version thereof (that
+has achieved REC status).</p><p>If the URI expressed by the content of the <code>ttp:feature</code> element,
+by the <code>extends</code> attribute, or by the <code>restricts</code> attribute
+is a relative URI, then an <code>xml:base</code> attribute should be
+specified on the nearest ancestor <code>ttp:features</code> element.</p><p>The <code>value</code> attribute specifies constraints on support for or use of
+the designated feature according to the profile type.</p><p>If the profile is a <a href="#terms-processor-profile">processor profile</a>
+then the following semantics apply:</p><ul><li><p>
+if the value of the <code>value</code> attribute
+is <code>optional</code>, then a processor may but need
+not implement or otherwise support the feature in order to process the document;
+</p></li><li><p>if the value is <code>required</code>, then perform the following steps:</p><ol class="enumar"><li><p>if the feature is implemented or otherwise supported by a processor, then continue processing
+the document;</p></li><li><p>otherwise, if
+(1) the <code>extends</code> attribute is specified on the root <code>tt</code> element,
+(2) the value of the <code>extends</code> attribute designates a feature that is implemented or otherwise supported by
+a processor, and
+(3) the computed value of the <a href="#profile-attribute-permitFeatureNarrowing"><code>ttp:permitFeatureNarrowing</code></a>
+profile property of the root <code>tt</code> element is not <code>false</code>,
+then continue processing the document;</p></li><li><p>otherwise, if
+(1) the <code>restricts</code> attribute is specified on the root <code>tt</code> element,
+(2) the value of the <code>restricts</code> attribute designates a feature that is implemented or otherwise supported by
+a processor, and
+(3) the computed value of the <a href="#profile-attribute-permitFeatureWidening"><code>ttp:permitFeatureWidening</code></a>
+profile property of the root <code>tt</code> element is not <code>false</code>,
+then continue processing the document;</p></li><li><p>otherwise, abort processing the document unless overridden by the end-user or some implementation specific parameter
+traceable to an end-user or to a user or system configuration setting.</p></li></ol></li><li><p>
+if the value attribute is not specified, then the feature specification
+must be interpreted as if the value <code>required</code> were specified;
+</p></li></ul><p>If the profile is a <a href="#terms-content-profile">content profile</a>
+then the following semantics apply:</p><ul><li><p>
+if the value of the <code>value</code> attribute
+is <code>optional</code>, then the feature may but need not appear in a document that
+claims conformance with that profile;
+</p></li><li><p>
+if the value of the <code>value</code> attribute
+is <code>required</code>, then the feature must appear in a document that
+claims conformance with that profile;
+</p></li><li><p>
+if the value of the <code>value</code> attribute
+is <code>prohibited</code>, then the feature must not appear in a document that
+claims conformance with that profile;
+</p></li><li><p>
+if the value attribute is not specified, then the feature specification
+must be interpreted as if the value <code>optional</code> were specified;
+</p></li></ul><p>The value <span class="obsoleted"><code>use</code></span> of the <code>value</code> attribute is <span class="obsoleted">obsoleted</span>. If it
+appears in a profile specification, then it must be interpreted as if <code>required</code>
+had been specified.</p><p>If some defined (i.e., standardized) or otherwise well known feature is not specified by
+a <code>ttp:feature</code> element in a content profile, then it must be interpreted as if the feature were specified
+with the <code>value</code> attribute equal to <code>optional</code>. However, if not specified in a processor profile, no claim
+about support or absence of support for the feature is implied.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In particular, if some feature is not present in a content profile definition, then
+it is not to be interpreted as meaning the use of that feature (in a <a href="#terms-document-instance">document instance</a>)
+is disallowed or otherwise prohibited. If a feature is intended to be disallowed by a content profile, then
+it should be specified using the <code>prohibited</code> value.</p></div><p>If a <a href="#terms-document-instance">document instance</a> makes use of a feature defined by
+<a href="#feature-designations"><b>E.1 Feature Designations</b></a> and if the intended use of the
+document requires the recognition and processing of that feature, then
+the document must include a <em>required</em> feature specification in one of its declared or
+referenced profiles.</p><p>The <code>ttp:feature</code> element is illustrated by the following example.</p><a id="profile-vocabulary-feature-example-1"></a><table class="example"><caption>Example Fragment – ttp:feature</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttp:profile use="http://www.w3.org/ns/ttml/profile/ttml2-presentation"&gt;
+  &lt;ttp:features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+    <span class="strong">&lt;ttp:feature value="required"&gt;#fontStyle-italic&lt;/ttp:feature&gt;</span>
+    <span class="strong">&lt;ttp:feature value="required"&gt;#textDecoration-under&lt;/ttp:feature&gt;</span>
+    <span class="strong">&lt;ttp:feature value="prohibited"&gt;#textOutline-blurred&lt;/ttp:feature&gt;</span>
+  &lt;/ttp:features&gt;
+&lt;/ttp:profile&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the TTML presentation profile is used as the
+baseline profile. This baseline profile is then modified by three
+<code>ttp:feature</code> elements in order to (1)
+superset the baseline profile (since neither
+<code>#fontStyle-italic</code> nor <code>#textDecoration-under</code>
+are required by the TTML presentation profile), and
+(2) prohibit use of the <code>#textOutline-blurred</code> feature
+(which is optional in the TTML presentation profile).</p><p>The effect of this example is to express authorial intentions that
+italic font style and text underlining must be
+supported, and that text outline blurring must not be used by a document.</p></div></div><div class="div3">
+<h4><a id="profile-vocabulary-extensions"></a>6.1.4 ttp:extensions</h4><p>The <code>ttp:extensions</code> element is a container element used to group
+infomation about extension support and usage requirements.</p><p>The <code>ttp:extensions</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by
+zero or more <code>ttp:extension</code> elements.</p><a id="elt-syntax-extensions"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:extensions</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttp:extensions
+  xml:base = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a> : <em>TT Extension Namespace</em>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#profile-vocabulary-extension">ttp:extension</a>*
+&lt;/ttp:extensions&gt;
+</pre></div>
+</td></tr></tbody></table><p>If specified, the <code>xml:base</code>
+attribute must (1) adhere to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17, (2) express an absolute URI that
+adheres to <a href="#xmlbase">[XML Base]</a> and,
+(3) express an extension namespace as defined by
+<a href="#extension-designations"><b>F.1 Extension Designations</b></a>. If not specified, the
+<code>xml:base</code> attribute's default
+value applies, which is the TT Extension Namespace.</p><p>The <code>xml:base</code> attribute is
+used to permit the abbreviation of feature designation URIs expressed
+by child <code>ttp:extension</code> elements.</p></div><div class="div3">
+<h4><a id="profile-vocabulary-extension"></a>6.1.5 ttp:extension</h4><p>The <code>ttp:extension</code> element is used to specify
+infomation about support and usage requirements for a particular extension.</p><a id="elt-syntax-extension"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttp:extension</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttp:extension
+  extends = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  restricts = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  value = (optional|required|<span class="obsoleted">use</span>|prohibited) : <em>see prose below</em>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA
+&lt;/ttp:extension&gt;
+</pre></div>
+</td></tr></tbody></table><p>The children of the <code>ttp:extension</code> element must express a non-empty
+sequence of <a href="#terms-character-information-item">character information items</a> the concatenation of which adheres to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17.</p><p>If specified, the <code>extends</code> attribute and/or the <code>restricts</code>
+attribute must (1) adhere to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17, and
+(2) express a feature designation or extension designation as defined by
+<a href="#feature-designations"><b>E.1 Feature Designations</b></a> or <a href="#extension-designations"><b>F.1 Extension Designations</b></a>, respectively.</p><p>The <code>extends</code> attribute may be used to indicate that the extension being defined
+is, from either (or both) a syntactic or (and) semantic perspective, a proper superset of the
+feature or extension referenced by the <code>extends</code> attribute.
+The <code>restricts</code> attribute may be used to indicate that the extension being defined
+is, from either (or both) a syntactic or (and) semantic perspective, a proper subset of the
+feature or extension referenced by the <code>restricts</code> attribute.
+If an <code>extends</code> attribute is specified, then a <code>restricts</code> attribute must
+not be specified on a <code>ttp:extension</code> element; likewise, if a <code>restricts</code> attribute
+is specified, then an <code>extends</code> attribute must not be specified.</p><p>If the URI expressed by (1) the content of the <code>ttp:extension</code>
+element, (2) the <code>extends</code> attribute, or (3) the <code>restricts</code> attribute
+is a relative URI, then, when combined with the
+extension namespace value expressed by the
+<code>xml:base</code> attribute of the
+nearest ancestor <code>ttp:extensions</code> element, it must express an
+absolute URI.  In either case (original absolute URI or resulting
+absolutized URI), the URI expressed by the <code>ttp:extension</code>
+element must further adhere to the syntax of an extension designation as
+defined by <a href="#extension-designations"><b>F.1 Extension Designations</b></a>,
+while the URI expressed by the <code>extends</code> attribute and/or the
+<code>restricts</code> attribute must adhere to the syntax of a feature designation
+or an extension designation as defined by <a href="#feature-designations"><b>E.1 Feature Designations</b></a> or
+<a href="#extension-designations"><b>F.1 Extension Designations</b></a>, respectively.</p><p>If the URI expressed by the content of the <code>ttp:extension</code> element,
+by the <code>extends</code> attribute, or by the <code>restricts</code> attribute
+is a relative URI, then an <code>xml:base</code> attribute should be
+specified on the nearest ancestor <code>ttp:extensions</code> element.</p><p>The <code>value</code> attribute specifies constraints on support for or use of
+the designated extension according to the profile type.</p><p>If the profile is a <a href="#terms-processor-profile">processor profile</a>
+then the following semantics apply:</p><ul><li><p>
+if the value of the <code>value</code> attribute
+is <code>optional</code>, then a processor may but need
+not implement or otherwise support the extension in order to process the document;
+</p></li><li><p>if the value is <code>required</code>, then perform the following steps:</p><ol class="enumar"><li><p>if the extension is implemented or otherwise supported by a processor, then continue processing
+the document;</p></li><li><p>otherwise, if
+(1) the <code>extends</code> attribute is specified on the root <code>tt</code> element,
+(2) the value of the <code>extends</code> attribute designates an extension that is implemented or otherwise supported by
+a processor, and
+(3) the computed value of the <a href="#profile-attribute-permitFeatureNarrowing"><code>ttp:permitFeatureNarrowing</code></a>
+profile property of the root <code>tt</code> element is not <code>false</code>,
+then continue processing the document;</p></li><li><p>otherwise, if
+(1) the <code>restricts</code> attribute is specified on the root <code>tt</code> element,
+(2) the value of the <code>restricts</code> attribute designates an extension that is implemented or otherwise supported by
+a processor, and
+(3) the computed value of the <a href="#profile-attribute-permitFeatureWidening"><code>ttp:permitFeatureWidening</code></a>
+profile property of the root <code>tt</code> element is not <code>false</code>,
+then continue processing the document;</p></li><li><p>otherwise, abort processing the document unless overridden by the end-user or some implementation specific parameter
+traceable to an end-user or to a user or system configuration setting.</p></li></ol></li><li><p>
+if the value attribute is not specified, then the extension specification
+must be interpreted as if the value <code>required</code> were specified;
+</p></li></ul><p>If the profile is a <a href="#terms-content-profile">content profile</a>
+then the following semantics apply:</p><ul><li><p>
+if the value of the <code>value</code> attribute
+is <code>optional</code>, then the extension may but need not appear in a document that
+claims conformance with that profile;
+</p></li><li><p>
+if the value of the <code>value</code> attribute
+is <code>required</code>, then the extension must appear in a document that
+claims conformance with that profile;
+</p></li><li><p>
+if the value of the <code>value</code> attribute
+is <code>prohibited</code>, then the extension must not appear in a document that
+claims conformance with that profile;
+</p></li><li><p>
+if the value attribute is not specified, then the extension specification
+must be interpreted as if the value <code>optional</code> were specified;
+</p></li></ul><p>The value <span class="obsoleted"><code>use</code></span> of the <code>value</code> attribute is <span class="obsoleted">obsoleted</span>. If it
+appears in a profile specification, then it must be interpreted as if <code>required</code>
+had been specified.</p><p>If some well known extension is not specified by
+a <code>ttp:extension</code> element in a content profile, then it must be interpreted as if the extension were specified
+with the <code>value</code> attribute equal to <code>optional</code>. However, if not specified in a processor profile, no claim
+about support or absence of support for the extension is implied.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In particular, if some extension is not present in a content profile definition, then
+it is not to be interpreted as meaning the use of that extension (in a <a href="#terms-document-instance">document instance</a>)
+is disallowed or otherwise prohibited. If an extension is intended to be disallowed by a content profile, then
+it should be specified using the <code>prohibited</code> value.</p></div><p>If a <a href="#terms-document-instance">document instance</a> makes use
+of an extension designatable by <a href="#extension-designations"><b>F.1 Extension Designations</b></a> and if the intended use of the document
+requires the recognition and processing of that extension, then the
+document must include a <em>required</em> extension specification
+in one of its declared or referenced profiles.</p><p>The <code>ttp:extension</code> element is illustrated by the following example.</p><a id="profile-vocabulary-extension-example-1"></a><table class="example"><caption>Example Fragment – ttp:extension</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttp:profile use="http://www.w3.org/ns/ttml/profile/ttml2-transformation"&gt;
+  &lt;ttp:extensions xml:base="http://example.org/ttml/extension/"&gt;
+    <span class="strong">&lt;ttp:extension value="use"&gt;#prefilter-by-language&lt;/ttp:extension&gt;</span>
+  &lt;/ttp:extensions&gt;
+&lt;/ttp:profile&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the TTML transformation profile is used as
+the baseline profile. This baseline profile is then supersetted by
+specifying that support and use is required for a private extension
+defined in a third party namespace.</p><p>The effect of this example is to express authorial intentions that
+a recipient processor must support the TTML transformation profile and
+must also support and enable an extension defined by a third party.</p></div></div></div><div class="div2">
+<h3><a id="profile-attribute-vocabulary"></a>6.2 Profile Attribute Vocabulary</h3><p>The following attributes are defined in the TT Parameter Namespace.</p><ul><li><p><a href="#profile-attribute-contentProfiles"><b>6.2.1 ttp:contentProfiles</b></a></p></li><li><p><a href="#profile-attribute-contentProfileCombination"><b>6.2.2 ttp:contentProfileCombination</b></a></p></li><li><p><a href="#profile-attribute-inferProcessorProfileMethod"><b>6.2.3 ttp:inferProcessorProfileMethod</b></a></p></li><li><p><a href="#profile-attribute-inferProcessorProfileSource"><b>6.2.4 ttp:inferProcessorProfileSource</b></a></p></li><li><p><a href="#profile-attribute-permitFeatureNarrowing"><b>6.2.5 ttp:permitFeatureNarrowing</b></a></p></li><li><p><a href="#profile-attribute-permitFeatureWidening"><b>6.2.6 ttp:permitFeatureWidening</b></a></p></li><li><p><a href="#profile-attribute-profile"><b>6.2.7 ttp:profile</b></a></p></li><li><p><a href="#profile-attribute-processorProfiles"><b>6.2.8 ttp:processorProfiles</b></a></p></li><li><p><a href="#profile-attribute-processorProfileCombination"><b>6.2.9 ttp:processorProfileCombination</b></a></p></li><li><p><a href="#profile-attribute-validation"><b>6.2.10 ttp:validation</b></a></p></li><li><p><a href="#profile-attribute-validationAction"><b>6.2.11 ttp:validationAction</b></a></p></li><li><p><a href="#profile-attribute-version"><b>6.2.12 ttp:version</b></a></p></li></ul><p>Unless explicitly stated otherwise, linear white-space (LWSP) must
+appear between adjacent non-terminal components of a TT Parameter value
+unless some other delimiter is permitted and used.</p><div class="div3">
+<h4><a id="profile-attribute-contentProfiles"></a>6.2.1 ttp:contentProfiles</h4><p>The <code>ttp:contentProfiles</code> attribute may be used by a content author
+to express one or more <a href="#terms-content-profile">content profiles</a> of
+the Timed Text Markup Language (TTML) where the
+<a href="#terms-enclosing-document-instance">enclosing document instance</a> claims conformance to any or all of the
+specified <a href="#terms-content-profile">content profiles</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax,
+where each <code>profile-designator</code> item adheres to the <code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17, and, further, adheres to constraints defined on a profile designator in accordance with
+<a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>.</p><a id="profile-attribute-contentProfiles-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:contentProfiles</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:contentProfiles
+  : designators
+  | "all(" designators ")"
+  | "any(" designators ")"
+
+designators
+  : designator (lwsp designator)*
+
+designator
+  : xsd:anyURI
+
+lwsp
+  : ( ' ' | '\t' | '\n' | '\r' )+
+</pre></div>
+</td></tr></tbody></table><p>If the list of designators is enclosed in the function syntax <code>all(...)</code> or no function syntax is used,
+then conformance is claimed with all designated <a href="#terms-content-profile">content profiles</a>. If the list
+of designators is enclosed in the function syntax <code>any(...)</code>, then conformance is claimed with at least one
+of the designated <a href="#terms-content-profile">content profiles</a>.</p><p>A <code>ttp:contentProfiles</code>
+attribute is considered to be significant only when specified on the
+<code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-contentProfileCombination"></a>6.2.2 ttp:contentProfileCombination</h4><p>The <code>ttp:contentProfileCombination</code> attribute is used to specify the
+method for combining multiple <a href="#terms-content-profile">content profiles</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-contentProfileCombination-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:contentProfileCombination</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:contentProfileCombination
+  : "leastRestrictive"
+  | "mostRestrictive"
+  | "replace"
+</pre></div>
+</td></tr></tbody></table><p>Given two ordered profile specification values, <em>arg1</em> and <em>arg2</em>, and a content profile combination method,
+<a href="#content-profile-combination-table"><b>Table 6-1 – Content Profile Combination</b></a> specifies the result of combining the two specification values, where the order
+of arguments is determined in accordance with the lexical order of
+<a href="#terms-content-profile">content profiles</a> in a <a href="#terms-document-instance">document instance</a>.</p><a id="content-profile-combination-table"></a><table class="common"><caption>Table 6-1 – Content Profile Combination</caption><col width="16.67%" span="1"><col width="16.67%" span="1"><col width="22%" span="1"><col width="22%" span="1"><col width="22%" span="1"><tbody><tr><th><em>arg1</em></th><th><em>arg2</em></th><th><code>leastRestrictive</code></th><th><code>mostRestrictive</code></th><th><code>replace</code></th></tr><tr><td>optional</td><td>optional</td><td>optional</td><td>optional</td><td>optional</td></tr><tr><td>optional</td><td>required</td><td>optional</td><td>required</td><td>required</td></tr><tr><td>optional</td><td>prohibited</td><td>optional</td><td>prohibited</td><td>prohibited</td></tr><tr><td>required</td><td>optional</td><td>optional</td><td>required</td><td>optional</td></tr><tr><td>required</td><td>required</td><td>required</td><td>required</td><td>required</td></tr><tr><td>required</td><td>prohibited</td><td>required</td><td>prohibited</td><td>prohibited</td></tr><tr><td>prohibited</td><td>optional</td><td>optional</td><td>prohibited</td><td>optional</td></tr><tr><td>prohibited</td><td>required</td><td>required</td><td>prohibited</td><td>required</td></tr><tr><td>prohibited</td><td>prohibited</td><td>prohibited</td><td>prohibited</td><td>prohibited</td></tr></tbody></table><p>A <code>ttp:contentProfileCombination</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-inferProcessorProfileMethod"></a>6.2.3 ttp:inferProcessorProfileMethod</h4><p>The <code>ttp:inferProcessorProfileMethod</code> attribute is used to specify the
+method for mapping a content profile specification value to a corresponding processor
+profile specification value.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-inferProcessorProfileMethod-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:inferProcessorProfileMethod</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:inferProcessorProfileMethod
+  : "loose"
+  | "strict"
+</pre></div>
+</td></tr></tbody></table><p>If this parameter's value is <code>loose</code>, then, when inferring a processor profile specification from a content profile specification,
+a loose (liberal) mapping applies.</p><p>If this parameter's value is <code>strict</code>, then, when inferring a processor profile specification from a content profile specification,
+a strict (conservative) mapping applies.</p><p>If not specified, the value of this parameter must be considered
+to be <code>loose</code>.</p><p>Given an input content profile specification value, <em>input</em>, and an infer processor profile method,
+<a href="#infer-processor-profile-method-table"><b>Table 6-2 – Infer Processor Profile Method</b></a> specifies the result of mapping the input specification value.</p><a id="infer-processor-profile-method-table"></a><table class="common"><caption>Table 6-2 – Infer Processor Profile Method</caption><col width="33%" span="1"><col width="33%" span="1"><col width="33%" span="1"><tbody><tr><th><em>input</em></th><th><code>loose</code></th><th><code>strict</code></th></tr><tr><td>optional</td><td>optional</td><td>required</td></tr><tr><td>required</td><td>required</td><td>required</td></tr><tr><td>prohibited</td><td>optional</td><td>optional</td></tr></tbody></table><p>A <code>ttp:inferProcessorProfileMethod</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-inferProcessorProfileSource"></a>6.2.4 ttp:inferProcessorProfileSource</h4><p>The <code>ttp:inferProcessorProfileSource</code> attribute is used to specify the
+source for mapping a content profile specification value to a corresponding processor
+profile specification value.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-inferProcessorProfileSource-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:inferProcessorProfileSource</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:inferProcessorProfileSource
+  : "combined"
+  | "first"
+</pre></div>
+</td></tr></tbody></table><p>If this parameter's value is <code>combined</code>, then, when inferring a processor profile, the combined profile specification
+set of the <a href="#terms-effective-content-profile">effective content profile</a> is used as the source of inference.</p><p>If this parameter's value is <code>first</code>, then, when inferring a processor profile, the first constituent profile of
+the <a href="#terms-effective-content-profile">effective content profile</a>, where the processor profile inferred from that
+constituent profile is supported by the <a href="#terms-content-processor">content processor</a>, is used as the source of inference.</p><p>If not specified, the value of this parameter must be considered
+to be <code>combined</code>.</p><p>A <code>ttp:inferProcessorProfileSource</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-permitFeatureNarrowing"></a>6.2.5 ttp:permitFeatureNarrowing</h4><p>The <code>ttp:permitFeatureNarrowing</code> attribute is used to specify whether
+requirements related to a feature or extension may be satisfied by a (syntactically or semantically) narrower interpretation
+of the feature or extension.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-permitFeatureNarrowing-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:permitFeatureNarrowing</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:permitFeatureNarrowing
+  : <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:boolean</a>                             // see <a href="#xsd-2">[XML Schema Part 2]</a>, §3.2.2
+</pre></div>
+</td></tr></tbody></table><p>If this parameter's value is <code>true</code>, then, a requirement for support of a feature or extension may be satisfied
+if the definition of the feature or extension specifies an <code>extends</code> attribute, and the feature or extension referenced
+by that attribute is supported by a processor.</p><p>If this parameter's value is <code>false</code>, then, a requirement for support of a feature or extension can not be satisfied
+by a more narrowly defined feature or extension specified by an <code>extends</code> attribute.</p><p>If not specified, the value of this parameter must be considered
+to be <code>false</code>.</p><p>A <code>ttp:permitFeatureNarrowing</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-permitFeatureWidening"></a>6.2.6 ttp:permitFeatureWidening</h4><p>The <code>ttp:permitFeatureWidening</code> attribute is used to specify whether
+requirements related to a feature or extension may be satisfied by a (syntactically or semantically) wider interpretation
+of the feature or extension.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-permitFeatureWidening-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:permitFeatureWidening</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:permitFeatureWidening
+  : <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:boolean</a>                             // see <a href="#xsd-2">[XML Schema Part 2]</a>, §3.2.2
+</pre></div>
+</td></tr></tbody></table><p>If this parameter's value is <code>true</code>, then, a requirement for support of a feature or extension may be satisfied
+if the definition of the feature or extension specifies an <code>restricts</code> attribute, and the feature or extension referenced
+by that attribute is supported by a processor.</p><p>If this parameter's value is <code>false</code>, then, a requirement for support of a feature or extension can not be satisfied
+by a more widely defined feature or extension specified by an <code>restricts</code> attribute.</p><p>If not specified, the value of this parameter must be considered
+to be <code>false</code>.</p><p>A <code>ttp:permitFeatureWidening</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-profile"></a>6.2.7 ttp:profile</h4><p>The <code>ttp:profile</code> attribute is <span class="deprecated">deprecated</span>. If creating a TTML document instance for TTML2 (or later versions),
+then the <code>ttp:profile</code> attribute should not be used; instead, the content author should use the <code>ttp:processorProfiles</code>
+attribute, specified at <a href="#profile-attribute-processorProfiles"><b>6.2.8 ttp:processorProfiles</b></a>.</p><p>If used in a document, the <code>ttp:profile</code> attribute
+denotes a <a href="#terms-processor-profile">processor profile</a>
+of the Timed Text Markup Language (TTML) that applies when processing
+a <a href="#terms-document-instance">document instance</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For information on signaling content profile(s), see <a href="#profile-attribute-contentProfiles"><b>6.2.1 ttp:contentProfiles</b></a>.</p></div><p>If specified, the value of this attribute must adhere to the following syntax
+where the <code>designator</code> adheres to the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17, and, further, must specify a
+profile designator in accordance with
+<a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>.</p><a id="profile-attribute-profile-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:profile</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+<span class="deprecated">ttp:profile</span>
+  : designator
+
+designator
+  : xsd:anyURI
+</pre></div>
+</td></tr></tbody></table><p>A <code>ttp:profile</code>
+attribute is considered to be significant only when specified on the
+<code>tt</code> element.</p><p>If a <a href="#terms-top-level-profile">top-level</a> <a href="#terms-processor-profile">processor profile</a>
+is defined in a <a href="#terms-document-instance">document instance</a>, then the
+<a href="#profile-attribute-profile"><code>ttp:profile</code></a>
+attribute should not be specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-processorProfiles"></a>6.2.8 ttp:processorProfiles</h4><p>The <code>ttp:processorProfiles</code> attribute may be used by a content author
+to express one or more <a href="#terms-processor-profile">processor profiles</a> of
+the Timed Text Markup Language (TTML) where the
+<a href="#terms-enclosing-document-instance">enclosing document instance</a> requires support for each and all
+specified <a href="#terms-processor-profile">processor profiles</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax,
+where each <code>profile-designator</code> item adheres to the <code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§3.2.17, and, further, adheres to constraints defined on a profile designator in accordance with
+<a href="#vocabulary-profiling"><b>5.2 Profiling</b></a>.</p><a id="profile-attribute-processorProfiles-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:processorProfiles</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:processorProfiles
+  : designators
+  | "all(" designators ")"
+  | "any(" designators ")"
+
+designators
+  : designator (lwsp designator)*
+
+designator
+  : xsd:anyURI
+
+lwsp
+  : ( ' ' | '\t' | '\n' | '\r' )+
+</pre></div>
+</td></tr></tbody></table><p>If the list of designators is enclosed in the function syntax <code>all(...)</code> or no function syntax is used,
+then support is required for all designated <a href="#terms-processor-profile">processor profiles</a>. If the list
+of designators is enclosed in the function syntax <code>any(...)</code>, then support is required for at least one
+of the designated <a href="#terms-processor-profile">processor profiles</a>.</p><p>A <code>ttp:processorProfiles</code>
+attribute is considered to be significant only when specified on the
+<code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-processorProfileCombination"></a>6.2.9 ttp:processorProfileCombination</h4><p>The <code>ttp:processorProfileCombination</code> attribute is used to specify the
+method for combining multiple <a href="#terms-processor-profile">processor profiles</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-processorProfileCombination-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:processorProfileCombination</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:processorProfileCombination
+  : "leastRestrictive"
+  | "mostRestrictive"
+  | "replace"
+</pre></div>
+</td></tr></tbody></table><p>Given two ordered profile specification values, <em>arg1</em> and <em>arg2</em>, and a processor profile combination method,
+<a href="#processor-profile-combination-table"><b>Table 6-3 – Processor Profile Combination</b></a> specifies the result of combining the two specification values, where the order
+of arguments is determined in accordance with the lexical order of
+<a href="#terms-processor-profile">processor profiles</a> in a <a href="#terms-document-instance">document instance</a>.</p><a id="processor-profile-combination-table"></a><table class="common"><caption>Table 6-3 – Processor Profile Combination</caption><col width="16.67%" span="1"><col width="16.67%" span="1"><col width="22%" span="1"><col width="22%" span="1"><col width="22%" span="1"><tbody><tr><th><em>arg1</em></th><th><em>arg2</em></th><th><code>leastRestrictive</code></th><th><code>mostRestrictive</code></th><th><code>replace</code></th></tr><tr><td>optional</td><td>optional</td><td>optional</td><td>optional</td><td>optional</td></tr><tr><td>optional</td><td>required</td><td>optional</td><td>required</td><td>required</td></tr><tr><td>required</td><td>optional</td><td>optional</td><td>required</td><td>optional</td></tr><tr><td>required</td><td>required</td><td>required</td><td>required</td><td>required</td></tr></tbody></table><p>A <code>ttp:processorProfileCombination</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-validation"></a>6.2.10 ttp:validation</h4><p>The <code>ttp:validation</code> attribute is used to specify whether validation processing
+may or must be performed on a <a href="#terms-document-instance">document instance</a> by a
+<a href="#terms-validating-content-processor">validating content processor</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-validation-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:validation</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:validation
+  : "required"
+  | "optional"
+  | "prohibited"
+</pre></div>
+</td></tr></tbody></table><p>If this parameter's value is <code>required</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
+must perform validation processing on a TTML <a href="#terms-document-instance">document instance</a> prior to performing
+other types of processing, e.g., presentation or transformation processing.</p><p>If this parameter's value is <code>optional</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
+may, but need not, perform validation processing on a TTML <a href="#terms-document-instance">document instance</a> prior to performing
+other types of processing, e.g., presentation or transformation processing.</p><p>If this parameter's value is <code>prohibited</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
+must not perform validation processing on a TTML <a href="#terms-document-instance">document instance</a> prior to performing
+other types of processing, e.g., presentation or transformation processing, unless the end-user or application overrides this prohibition.</p><p>If validation processing is performed on a TTML <a href="#terms-document-instance">document instance</a> and validation fails, then the computed value of
+the <code>ttp:validationAction</code> parameter property is used to determine what action to take before performing further processing.</p><p>If not specified, the value of this parameter must be considered
+to be <code>optional</code>.</p><p>A <code>ttp:validation</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-validationAction"></a>6.2.11 ttp:validationAction</h4><p>The <code>ttp:validationAction</code> attribute is used to specify what action is to be taken
+by a <a href="#terms-validating-content-processor">validating content processor</a> when
+validation of a <a href="#terms-document-instance">document instance</a> fails.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-validationAction-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:validationAction</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:validationAction
+  : "abort"
+  | "warn"
+  | "ignore"
+</pre></div>
+</td></tr></tbody></table><p>If this parameter's value is <code>abort</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
+must abort processing of a TTML <a href="#terms-document-instance">document instance</a> when validation processing fails.</p><p>If this parameter's value is <code>warn</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
+should warn the end-user when validation processing fails, and, give the end-user the option to continue or abort processing.</p><p>If this parameter's value is <code>ignore</code>, then, a <a href="#terms-validating-content-processor">validating content processor</a>
+should not abort and should not warn the end-user when validation processing fails.</p><p>If not specified, the value of this parameter is determined as follows:
+if the computed value of the <a href="#profile-attribute-validation"><code>ttp:validation</code></a> parameter property is <code>required</code>,
+then the value must be considered to be <code>abort</code>;
+if it is <code>optional</code>,
+then the value must be considered to be <code>warn</code>;
+otherwise, if it is <code>prohibited</code>,
+then the value must be considered to be <code>ignore</code>.</p><p>A <code>ttp:validationAction</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="profile-attribute-version"></a>6.2.12 ttp:version</h4><p>The <code>ttp:version</code> attribute is used to specify which version of the
+<a href="#terms-timed-text-markup-language">Timed Text Markup Language</a>
+specification was used in authoring a TTML <a href="#terms-document-instance">document instance</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="profile-attribute-version-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:version</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:version
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+                                // <em>value</em> &gt; 0
+</pre></div>
+</td></tr></tbody></table><p>A <code>ttp:version</code> attribute must be specified on the root <code>tt</code>
+element of a <a href="#terms-document-instance">document instance</a> if it
+requires support for a <a href="#terms-feature">feature</a> not defined by <a href="#ttml1">[TTML1]</a>.</p><p>If not specified, the version must be considered to be
+equal to one (1). If specified, then the version must be greater than zero (0). The version associated
+with this version of the <a href="#terms-timed-text-markup-language">Timed Text Markup Language</a>
+specification is two (2).</p><p>A <code>ttp:version</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <a href="#terms-content-processor">content processor</a> typically uses the
+declared version to perform a preliminary assessment of whether it is capable of
+processing a given <a href="#terms-document-instance">document instance</a>.
+However, it does not assume that the <a href="#terms-document-instance">document instance</a>
+actually uses or requires support for a <a href="#terms-feature">feature</a>
+not defined in prior versions. In other
+words, a <a href="#terms-content-processor">content processor</a> does not reject
+a <a href="#terms-document-instance">document instance</a> simply because it declares
+it was authored against a version of the <a href="#terms-timed-text-markup-language">Timed Text Markup Language</a>
+specification that was not yet published at the time the processor was implemented.</p><p>The computed value of the parameter property expresssed by the <code>ttp:version</code> attribute is used by the
+<a href="#semantics-procedure-construct-default-processor-profile"><span class="strong">construct default processor profile</span></a>
+procedure to determine the <a href="#terms-default-processor-profile">default processor profile</a>.</p></div></div></div></div><div class="div1">
+<h2><a id="parameter"></a>7 Parameter</h2><p>This section specifies the <em>parameter</em> matter of the
+core vocabulary catalog, where
+parameters are to be understood as information that is either (1)
+essential or (2) of significant importance for the purpose of
+interpreting the semantics of other types of information expressed by
+core vocabulary items or for establishing a <a href="#terms-document-processing-context">document processing context</a> by means
+of which TTML Content can be related to an external environment.</p><div class="div2">
+<h3><a id="parameter-element-vocabulary"></a>7.1 Parameter Element Vocabulary</h3><p>No parameter element vocabulary is defined in this specification.</p></div><div class="div2">
+<h3><a id="parameter-attribute-vocabulary"></a>7.2 Parameter Attribute Vocabulary</h3><p>The following attributes are defined in the TT Parameter Namespace.</p><ul><li><p><a href="#parameter-attribute-cellResolution"><b>7.2.1 ttp:cellResolution</b></a></p></li><li><p><a href="#parameter-attribute-clockMode"><b>7.2.2 ttp:clockMode</b></a></p></li><li><p><a href="#parameter-attribute-dropMode"><b>7.2.3 ttp:dropMode</b></a></p></li><li><p><a href="#parameter-attribute-frameRate"><b>7.2.4 ttp:frameRate</b></a></p></li><li><p><a href="#parameter-attribute-frameRateMultiplier"><b>7.2.5 ttp:frameRateMultiplier</b></a></p></li><li><p><a href="#parameter-attribute-markerMode"><b>7.2.6 ttp:markerMode</b></a></p></li><li><p><a href="#parameter-attribute-mediaDuration"><b>7.2.7 ttp:mediaDuration</b></a></p></li><li><p><a href="#parameter-attribute-mediaOffset"><b>7.2.8 ttp:mediaOffset</b></a></p></li><li><p><a href="#parameter-attribute-pixelAspectRatio"><b>7.2.9 ttp:pixelAspectRatio</b></a></p></li><li><p><a href="#parameter-attribute-storageAspectRatio"><b>7.2.10 ttp:storageAspectRatio</b></a></p></li><li><p><a href="#parameter-attribute-subFrameRate"><b>7.2.11 ttp:subFrameRate</b></a></p></li><li><p><a href="#parameter-attribute-tickRate"><b>7.2.12 ttp:tickRate</b></a></p></li><li><p><a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a></p></li></ul><p>Unless explicitly stated otherwise, linear white-space (LWSP) must
+appear between adjacent non-terminal components of a TT Parameter value
+unless some other delimiter is permitted and used.</p><div class="div3">
+<h4><a id="parameter-attribute-cellResolution"></a>7.2.1 ttp:cellResolution</h4><p>The <code>ttp:cellResolution</code> attribute may be used by an author
+to express the number of horizontal and vertical cells into which the <a href="#terms-root-container-region">root container region</a>
+area is divided for the purpose of expressing presentation semantics in terms of
+a uniform grid.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-cellResolution-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:cellResolution</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:cellResolution
+  : columns rows                            // <em>columns</em> != 0; <em>rows</em> != 0
+
+columns | rows
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+</pre></div>
+</td></tr></tbody></table><p>If not specified, the number of columns and rows must be considered
+to be 32 and 15, respectively. If specified, then columns or rows must not be zero (0).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The choice of values 32 and 15 are based on this being the
+maximum number of columns and rows defined by <a href="#cea608e">[CEA-608-E]</a>.</p></div><p>A <code>ttp:cellResolution</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of a uniform grid is employed only for the purpose of
+measuring lengths and expressing coordinates. In particular, it is not
+assumed that the presentation of text or the alignment of individual
+glyph areas is
+coordinated with this grid. Such alignment is possible, but
+requires the use of a monospaced font and a font size whose EM square exactly
+matches the cell size.</p></div><p>Except where indicated otherwise, when a <a href="#style-value-length">&lt;length&gt;</a> expressed in
+cells denotes a dimension parallel to the inline or block progression dimension,
+the cell's dimension in the inline or block progression dimension applies, respectively.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, if padding (on all four edges) is specified as 0.1c, the cell resolution
+is 20 by 10, and the extent of the <a href="#terms-root-container-region">root container region</a> is 640 by 480, then, assuming top to bottom,
+left to right writing mode, the start and end padding will be (640 / 20) * 0.1 pixels and the
+before and after padding will be (480 / 10) * 0.1 pixels.</p></div></div><div class="div3">
+<h4><a id="parameter-attribute-clockMode"></a>7.2.2 ttp:clockMode</h4><p>The <code>ttp:clockMode</code> attribute is used to specify the
+interpretation of time expressions as real-time time coordinates when
+operating with time base of <code>clock</code> as defined by <a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#timing-time-value-expressions"><b>12.3 Time Value Expressions</b></a> for the
+specification of time expression syntax and semantics.</p></div><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-clockMode-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:clockMode</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:clockMode
+  : "local"
+  | "gps"
+  | "utc"
+</pre></div>
+</td></tr></tbody></table><p>If the time base, defined by <a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>, is designated as
+<code>clock</code>, then this parameter applies as follows: if the
+parameter's value is <code>local</code>, then time expressions are
+interpreted as local wall-clock time coordinates;
+if <code>utc</code>, then time expressions are
+interpreted as UTC time coordinates
+<a href="#utc">[UTC]</a>;
+if <code>gps</code>, then time expressions are
+interpreted as GPS time coordinates
+<a href="#gps">[GPS]</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The primary difference between GPS time and UTC time is that GPS
+time is not adjusted for leap seconds, while UTC time is adjusted as
+follows: UTC = TAI (<em>Temp Atomique International</em>) + <em>leap seconds
+accumulated since 1972</em>. TAI is maintained by the <em>Bureau
+International des Poids et Mesures</em> (BIPM) in Sevres, France.
+The GPS system time is steered to a Master Clock (MC) at the US Naval
+Observatory which is kept within a close but unspecified
+tolerance of TAI.</p></div><p>If not specified, the value of this parameter must be considered
+to be <code>utc</code>.</p><p>A <code>ttp:clockMode</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="parameter-attribute-dropMode"></a>7.2.3 ttp:dropMode</h4><p>The <code>ttp:dropMode</code> attribute is used to specify
+constraints on the interpretation and use of frame counts
+that correspond with <a href="#smpte12m">[SMPTE 12M]</a> time coordinates when operating
+with time base of <code>smpte</code> as defined by
+<a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-dropMode-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:dropMode</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:dropMode
+  : "dropNTSC"
+  | "dropPAL"
+  | "nonDrop"
+</pre></div>
+</td></tr></tbody></table><p>If the time base, defined by <a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>, is designated as
+<code>smpte</code>, then this parameter applies as follows: if the
+parameter's value is <code>nonDrop</code>, then, within any given
+second of a time expression, frames count from 0 to
+<em>N−1</em>, where <em>N</em> is the value specified by
+the <code>ttp:frameRate</code> parameter, but while ignoring any value
+specified by the <code>ttp:frameRateMultiplier</code> parameter.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When operating in <code>nonDrop</code>
+mode, a second of a time expression may or may not be equal to a
+second of real time during normal (1x speed) forward playback. If the
+<code>ttp:frameRateMultiplier</code> parameter is specified and is not
+equal to 1:1, then a second of a time expression will either be
+shorter or longer than a second of elapsed play in real
+time.</p></div><p>If this parameter's value is <code>dropNTSC</code>, then, within any
+given second of a time expression except the second <code>00</code>,
+frames count from 0 to <em>N−1</em>, where <em>N</em> is
+the value specified by the <code>ttp:frameRate</code> parameter, but
+while ignoring any value specified by the
+<code>ttp:frameRateMultiplier</code> parameter. If the second of a time
+expression is <code>00</code> and the minute of the time expression is
+not <code>00</code>, <code>10</code>, <code>20</code>, <code>30</code>,
+<code>40</code>, or <code>50</code>, then frame codes <code>00</code>
+and <code>01</code> are dropped during that second; otherwise, these
+frame codes are not dropped.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, when operating in <code>dropNTSC</code>
+mode with <code>ttp:frameRate</code> of <code>30</code>, a discontinuity
+in frame count occurs between consecutive frames as shown in the
+following sequence of time expressions: <code>01:08:59:28</code>,
+<code>01:08:59:29</code>, <code>01:09:00:02</code>,
+<code>01:09:00:03</code>.</p></div><p>If this parameter's value is <code>dropPAL</code>, then, within any
+given second of a time expression except the second <code>00</code>,
+frames count from 0 to <em>N−1</em>, where <em>N</em> is
+the value specified by the <code>ttp:frameRate</code> parameter, but
+while ignoring any value specified by the
+<code>ttp:frameRateMultiplier</code> parameter. If the second of a time
+expression is <code>00</code> and the minute of the time expression is
+even but not <code>00</code>, <code>20</code>, or <code>40</code>,
+then frame codes <code>00</code> through <code>03</code> are dropped
+during that second; otherwise, these frame codes are not dropped.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, when operating in <code>dropPAL</code>
+mode with <code>ttp:frameRate</code> of <code>30</code>, a discontinuity
+in frame count occurs between consecutive frames as shown in the
+following sequence of time expressions: <code>01:09:59:28</code>,
+<code>01:09:59:29</code>, <code>01:10:00:04</code>,
+<code>01:10:00:05</code>.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The <code>dropPAL</code> mode is also known as the
+<em>M/PAL</em> or <em>PAL (M)</em> drop-frame
+code, which uses PAL modulation with the NTSC frame rate of ~29.97
+frames/second. The M/PAL system is used primarily in Brazil.</p></div><p>If not specified, then <code>nonDrop</code> must be assumed to apply.</p><p>A <code>ttp:dropMode</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="parameter-attribute-frameRate"></a>7.2.4 ttp:frameRate</h4><p>The <code>ttp:frameRate</code> attribute is used to specify the frame rate of a related
+media object or the intrinsic frame rate of a <a href="#terms-document-instance">document instance</a> in case it is intended
+to function as an independent media object.</p><div class="issue"><p class="prefix"><a id="issue-333"></a><b>Issue (issue-333):</b></p><p class="prefix"><b>Defaulting Frame Rate Multiplier, Sub Frame Rate</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/333">http://www.w3.org/AudioVideo/TT/tracker/issues/333</a></p><p>If frame rate is defaulted to processing environment, then frame rate multiplier and sub frame rate should be as well.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-frameRate-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:frameRate</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:frameRate
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+                                // <em>value</em> &gt; 0
+</pre></div>
+</td></tr></tbody></table><p>The frame rate that applies to a <a href="#terms-document-instance">document instance</a> is used to
+interpret time expressions that are expressed in <em>frames</em>
+as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>If the <code>media</code> time base applies and the effective frame rate is
+integral, then a frame is interpreted as a division of a second of media
+time, such that if the frame rate is specified as <em>F</em>, then
+a second of media time is divided into <em>F</em> intervals of
+equal duration, where each interval is labeled as frame <em>f</em>,
+with <em>f</em> ∈ [0…<em>F−1</em>].</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> for further details
+on the interpretation of time expressions for the <code>media</code> time base.</p></div><p>If not specified, the frame rate must be considered to be equal to some
+application defined frame rate, or if no application defined frame rate applies,
+then thirty (30) frames per second. If specified, then the frame rate must
+be greater than zero (0).</p><p>A <code>ttp:frameRate</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="parameter-attribute-frameRateMultiplier"></a>7.2.5 ttp:frameRateMultiplier</h4><p>The <code>ttp:frameRateMultiplier</code> attribute is used to
+specify a multiplier to be applied to the frame rate specified by a
+<code>ttp:frameRate</code> attribute in order to compute the effective
+frame rate.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-frameRateMultiplier-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:frameRateMultiplier</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:frameRateMultiplier
+  : numerator denominator                   // <em>numerator</em> != 0; <em>denominator</em> != 0
+
+numerator | denominator
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+</pre></div>
+</td></tr></tbody></table><p>A frame rate multiplier is used when the desired frame rate cannot
+be expressed as an integral number of frames per second.</p><p>If not specified, the frame rate multiplier must be considered to be equal to one (1:1).
+Both numerator and denominator must be non-zero.</p><p>A <code>ttp:frameRateMultiplier</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The frame rate multiplier used for synchronizing with NTSC <a href="#smpte170m">[SMPTE 170M]</a>
+formatted video objects at 30 frames per second is nominally
+1000:1001. The nominal frame rate of NTSC video is defined as the chrominance
+sub-carrier frequency of 3,579,545.45…Hz (= 5.0MHz × 63/88) times the ratio 2/455 divided by
+the number of horizontal lines per frame of 525, which yields a frame
+rate of 29.970029970029… (= 30 × 1000/1001) frames per
+second. Other frame rate multipliers apply to different regions of
+usage and video format standards.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Except in the case of PAL/M, the frame rate multiplier used for synchronizing with PAL
+formatted video objects at 25 frames per second is nominally 1:1.</p></div></div><div class="div3">
+<h4><a id="parameter-attribute-markerMode"></a>7.2.6 ttp:markerMode</h4><p>The <code>ttp:markerMode</code> attribute is used to specify
+constraints on the interpretation and use of time expressions
+that correspond with <a href="#smpte12m">[SMPTE 12M]</a> time coordinates when operating
+with time base of <code>smpte</code> as defined by
+<a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-markerMode-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:markerMode</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:markerMode
+  : "continuous"
+  | "discontinuous"
+</pre></div>
+</td></tr></tbody></table><p>If the time base, defined by <a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a>, is designated as
+<code>smpte</code>, then this parameter applies as follows: if the
+parameter's value is <code>continuous</code>, then <a href="#smpte12m">[SMPTE 12M]</a> time coordinates
+may be assumed to be linear and either monotonically increasing or
+decreasing; however, if <code>discontinuous</code>, then any assumption
+must not be made regarding linearity or monotonicity of time coordinates.</p><p>If not specified, the value of this parameter must be considered
+to be <code>discontinuous</code>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The default value for this parameter was originally specified
+(in <a href="http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/">TTML 1.0 First Edition</a>)
+as <code>continuous</code>; however, further evaluation of the state of the industry indicated this
+choice was incorrect, and that the most common default is <code>discontinuous</code>.</p></div><p>A <code>ttp:markerMode</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p><p>If a value of <code>continuous</code> applies, then time
+expressions may be converted to real time
+coordinates by taking into account the computed frame rate
+and drop mode as expressed by the <code>ttp:dropMode</code> parameter.
+In this case, the <a href="#terms-content-processor">content processor</a> must create and maintain a
+<a href="#terms-synthetic-smpte-document-syncbase">synthetic smpte document syncbase</a> within which these time
+expressions are interpreted as further described in
+<a href="#semantics-timing"><b>12.4 Timing Semantics</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When operating with <code>smpte</code> time base and
+<code>continuous</code> marker mode, there is an implied time coordinate
+space, the <a href="#terms-synthetic-smpte-document-syncbase">synthetic smpte document syncbase</a>,
+defined by the monotonically increasing (or decreasing) 
+<a href="#smpte12m">[SMPTE 12M]</a> time coordinates, while taking into account
+the computed frame rate and drop mode. All time expressions are interpreted
+in relationship to this time coordinate space based upon
+<a href="#terms-smpte-time-code">smpte time code</a> synchronization events (markers),
+where the <a href="#terms-document-processing-context">document processing context</a> emits these events with implied constraints
+regarding time coordinate monoticity and resynchronization in
+the presence of dropped frames.</p><p>Use of <code>continuous</code> marker mode with the <code>smpte</code>
+time base is different from using the <code>media</code> time base
+because (1) the semantics of the <code>ttp:dropMode</code> parameter
+apply to the former, but not the latter, and (2) <a href="#smpte12m">[SMPTE 12M]</a>
+time coordinates may be applied monotonically to media which has been
+subjected to dilation in time, constriction in time, or reversal in
+time.</p></div><p>If a value of <code>discontinuous</code> applies, then time
+expressions must not be converted to real time
+coordinates, arithmetical operators (addition, multiplication) are not
+defined on time expressions, and, consequently, any (well-formed)
+expression of a duration must be considered to be invalid.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When operating with <code>smpte</code> time base and
+<code>discontinuous</code> marker mode, there is no effective time coordinate
+space; rather, all time expressions are interpreted as labeled
+synchronization events (markers), where the <a href="#terms-document-processing-context">document processing context</a>
+emits these events, which, when they correspond with time
+expressions that denote the same label, cause a temporal interval to
+begin or end accordingly.</p><p>An additional side-effect of operating in <code>discontinuous</code>
+mode is that time expressions of children have no necessary
+relationship with time expressions of their temporal container; that
+is, temporal containers and children of these containers are
+temporally activated and inactivated independently based on the
+occurrence of a labeled synchronization (marker) event.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The notion of marker discontinuity as captured by this parameter
+is logically independent from the method used to count frames as
+expressed by the <code>ttp:dropMode</code> parameter. In particular,
+even if the <code>ttp:dropMode</code> parameter is specified as
+<code>dropNTSC</code> or <code>dropPAL</code>, the marker mode may be
+specified as <code>continuous</code>, even in the presence of frame count
+discontinuities induced by the frame counting method, unless there
+were some other non-linearity or discontinuity in marker labeling, for
+example, two consecutive frames labeled as <code>10:00:00:00</code>
+and <code>10:00:01:00</code>.
+</p></div></div><div class="div3">
+<h4><a id="parameter-attribute-mediaDuration"></a>7.2.7 ttp:mediaDuration</h4><p>The <code>ttp:mediaDuration</code> attribute is used to specify the
+temporal extent (simple duration) of a <a href="#terms-related-media-object">related media object</a>.</p><p>If the temporal extent (simple duration) of the <a href="#terms-related-media-object">related media object</a> is known at authoring time, then this
+attribute should be specified; otherwise, if no <a href="#terms-related-media-object">related media object</a> applies or its
+temporal extent is unknown, then this attribute should not be specified.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-mediaDuration-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:mediaDuration</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:mediaDuration
+  : <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>                        // restricted to <em>offset-time</em> form
+  | "indefinite"
+</pre></div>
+</td></tr></tbody></table><p>If specified, the value of this parameter must either (1) adhere to the <em>offset-time</em> form of
+a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> or (2) take the value <code>indefinite</code>.</p><p>If the value <code>indefinite</code> is specified, then there is no <a href="#terms-related-media-object">related media object</a>,
+the temporal extent (simple duration) of the
+<a href="#terms-related-media-object">related media object</a> is not known at the time this attribute is
+encoded, or the <a href="#terms-related-media-object">related media object</a> has no temporal end point.</p><p>If not specified, the value of this parameter must be considered
+to be <code>indefinite</code>.</p><p>A <code>ttp:mediaDuration</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#timing-time-value-expressions"><b>12.3 Time Value Expressions</b></a> for the
+specification of time expression syntax and semantics.</p></div></div><div class="div3">
+<h4><a id="parameter-attribute-mediaOffset"></a>7.2.8 ttp:mediaOffset</h4><p>The <code>ttp:mediaOffset</code> attribute is used to specify the
+temporal offset between the begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a>
+and the begin time of a <a href="#terms-related-media-object">related media object</a> when operating in a
+<a href="#time-expression-semantics-media">Media Time Base</a>
+or a <a href="#time-expression-semantics-smpte">SMPTE Time Base</a>. It does not apply and
+must not be specified when operating in a <a href="#time-expression-semantics-clock">Clock Time Base</a>.</p><div class="issue"><p class="prefix"><a id="issue-270"></a><b>Issue (issue-270):</b></p><p class="prefix"><b>Media Time Offset</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/270">http://www.w3.org/AudioVideo/TT/tracker/issues/270</a></p><p>Tie up loose ends with respect to definition of media time offset, particulary regarding the definition of the origin and beginning of
+the document temporal extent.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><div class="issue"><p class="prefix"><a id="issue-335"></a><b>Issue (issue-335):</b></p><p class="prefix"><b>Media Time Offset</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/335">http://www.w3.org/AudioVideo/TT/tracker/issues/335</a></p><p>Tie up loose ends with respect to definition of media time offset, particulary regarding the definition of the origin and beginning of
+the document temporal extent.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-mediaOffset-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:mediaOffset</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:mediaOffset
+  : sign? <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>                  // restricted to <em>offset-time</em> form
+
+sign
+  : "+" | "-"
+</pre></div>
+</td></tr></tbody></table><p>If specified, the value of this parameter must adhere to the <em>offset-time</em> form of
+a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> optionally expressed with a sign.
+If not specified, the value of this parameter must be considered
+to be <code>0s</code>.</p><p>If no sign is specified or it is specified as <code>+</code>, then the begin time of the
+<a href="#terms-root-temporal-extent">root temporal extent</a> follows the begin time of the
+<a href="#terms-related-media-object">related media object</a>; otherwise (sign is present and
+specified as <code>-</code>), the begin time of the
+<a href="#terms-root-temporal-extent">root temporal extent</a> precedes the begin time of the
+<a href="#terms-related-media-object">related media object</a>.</p><p>A <code>ttp:mediaOffset</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#timing-time-value-expressions"><b>12.3 Time Value Expressions</b></a> for the
+specification of time expression syntax and semantics.</p></div></div><div class="div3">
+<h4><a id="parameter-attribute-pixelAspectRatio"></a>7.2.9 ttp:pixelAspectRatio</h4><p>The <code>ttp:pixelAspectRatio</code> attribute may be used to express the <a href="#terms-pixel-aspect-ratio">pixel aspect ratio</a> associated with the
+<a href="#terms-authoring-viewport">authoring viewport</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-pixelAspectRatio-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:pixelAspectRatio</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:pixelAspectRatio
+  : numerator demoninator                   // <em>numerator</em> != 0; <em>demoninator</em> != 0
+
+numerator | demoninator
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+</pre></div>
+</td></tr></tbody></table><p>If not specified, then square pixels (i.e., aspect ratio 1:1) must be assumed to apply.
+If specified, then both numerator and demoninator must be non-zero.</p><p>A <code>ttp:pixelAspectRatio</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="parameter-attribute-storageAspectRatio"></a>7.2.10 ttp:storageAspectRatio</h4><p>The <code>ttp:storageAspectRatio</code> attribute may be used to express the <a href="#terms-storage-aspect-ratio">storage aspect ratio</a> associated with the
+<a href="#terms-authoring-viewport">authoring viewport</a>.</p><div class="issue"><p class="prefix"><a id="issue-201"></a><b>Issue (issue-201):</b></p><p class="prefix"><b>Maintaining Display Aspect Ratio</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/201">http://www.w3.org/AudioVideo/TT/tracker/issues/201</a></p><p>Tie up loose ends with respect to support for retaining display aspect ratio. See also new values of <a href="#style-attribute-extent"><code>tts:extent</code></a>:
+<code>contain</code> and <code>cover</code>.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-storageAspectRatio-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:storageAspectRatio</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:storageAspectRatio
+  : numerator demoninator                   // <em>numerator</em> != 0; <em>demoninator</em> != 0
+
+numerator | demoninator
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+</pre></div>
+</td></tr></tbody></table><p>If specified, then both numerator and demoninator must be non-zero.
+If not specified, then the storage aspect ratio of the <a href="#terms-authoring-viewport">authoring viewport</a> is undefined.</p><p>A <code>ttp:storageAspectRatio</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="parameter-attribute-subFrameRate"></a>7.2.11 ttp:subFrameRate</h4><p>The <code>ttp:subFrameRate</code> attribute is used to specify the sub-frame rate of a related
+media object or the intrinsic sub-frame rate of a <a href="#terms-document-instance">document instance</a> in case it is intended
+to function as an independent media object.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-subFrameRate-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:subFrameRate</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:subFrameRate
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+                                // <em>value</em> &gt; 0
+</pre></div>
+</td></tr></tbody></table><p>The sub-frame rate that applies to a <a href="#terms-document-instance">document instance</a> is used to
+interpret time expressions that are expressed in <em>sub-frames</em>
+as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>If the <code>media</code> time base applies and the effective frame rate is
+integral, a sub-frame is interpreted as a division of a frame of media
+time, such that if the sub-frame rate is specified as <em>S</em>, then
+a frame of media time is divided into <em>S</em> intervals of
+equal duration, where each interval is labeled as sub-frame <em>s</em>,
+with <em>s</em> ∈ [0…<em>S−1</em>].</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> for further details
+on the interpretation of time expressions for the <code>media</code> time base.</p></div><p>If not specified, the sub-frame rate must be considered to be
+equal to one (1). If specified, then the sub-frame rate must be greater than zero (0).</p><p>A <code>ttp:subFrameRate</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The sub-frame is sometimes referred to as a <em>field</em> in
+the context of synchronization with an interlaced video media object.</p></div></div><div class="div3">
+<h4><a id="parameter-attribute-tickRate"></a>7.2.12 ttp:tickRate</h4><p>The <code>ttp:tickRate</code> attribute is used to specify the tick rate of a related
+media object or the intrinsic tick rate of content of a <a href="#terms-document-instance">document instance</a> in case it is intended
+to function as an independent media object.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-tickRate-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:tickRate</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:tickRate
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+                                // <em>value</em> &gt; 0
+</pre></div>
+</td></tr></tbody></table><p>The tick rate that applies to a <a href="#terms-document-instance">document instance</a> is used to
+interpret time expressions that are expressed in <em>ticks</em> by
+using the <code>t</code> metric as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>If the <code>media</code> time base applies,
+a tick is interpreted as an integral division of a second of media
+time, such that if the tick rate is specified as <em>T</em>, then
+a second of media time is divided into <em>T</em> intervals of
+equal duration, where each interval is labeled as tick <em>t</em>,
+with <em>t</em> ∈ [0…<em>T−1</em>].</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> for further details
+on the interpretation of time expressions for the <code>media</code> time base.</p></div><p>If not specified, then if a frame rate is specified, the tick rate
+must be considered to be the effective frame rate multiplied by the
+sub-frame rate (i.e., ticks are interpreted as sub-frames); or, if no
+frame rate is specified, the tick rate must be considered to be one (1)
+tick per second of media time. If specified, then the tick rate
+must not be zero (0).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>There is no predefined relationship between ticks and frames or
+sub-frames. Ticks are an arbitrary division of seconds that permit
+use of fixed point arithmetic rather than fractional (and potentially
+inexact) expressions of seconds.</p></div><p>A <code>ttp:tickRate</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p></div><div class="div3">
+<h4><a id="parameter-attribute-timeBase"></a>7.2.13 ttp:timeBase</h4><p>The <code>ttp:timeBase</code> attribute is used to specify the
+temporal coordinate system by means of which time expressions are
+interpreted in a <a href="#terms-document-instance">document instance</a>.</p><p>If specified, the value of this attribute must adhere to the following syntax:</p><a id="parameter-attribute-timeBase-syntax"></a><table class="syntax"><caption>Syntax Representation – ttp:timeBase</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttp:timeBase
+  : "media"
+  | "smpte"
+  | "clock"
+</pre></div>
+</td></tr></tbody></table><p>If the time base is designated as <code>media</code>, then a time
+expression denotes a coordinate in some media object's time line,
+where the media object may be an external media object with which the
+content of a <a href="#terms-document-instance">document instance</a> is to be synchronized, or it may
+be the content of a <a href="#terms-document-instance">document instance</a> itself in a case where
+the timed text content is intended to establish an independent time
+line.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When using a media time base, if that time base is paused or
+scaled positively or negatively, i.e., the media play rate is
+not unity, then it is expected that the
+presentation of associated Timed Text content will be similarly
+paused, accelerated, or decelerated, respectively. The means for
+controlling an external
+media time base is outside the scope of this specification.</p></div><p>If the time base is designated as <code>smpte</code>,
+then a time expression denotes a <a href="#smpte12m">[SMPTE 12M]</a> time
+coordinate with which the content of a <a href="#terms-document-instance">document instance</a> is to
+be synchronized.  In this case, the value of the <code>ttp:markerMode</code> 
+and <code>ttp:dropMode</code> parameters apply, as defined by <a href="#parameter-attribute-markerMode"><b>7.2.6 ttp:markerMode</b></a> and <a href="#parameter-attribute-dropMode"><b>7.2.3 ttp:dropMode</b></a>, respectively.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When the time base is designated as <code>smpte</code>,
+every time expression denotes a media marker value akin to that
+defined by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3, except instead
+of using an opaque marker name, a structured <a href="#smpte12m">[SMPTE 12M]</a>
+time coordinate serves as the marker name.</p></div><p>If the time base is designated as <code>clock</code>, then the time
+expression denotes a coordinate in some real-world time line as
+established by some real-time clock, such as the local wall-clock time
+or UTC (Coordinated Universal Time) or GPS (Global Positioning System)
+time lines.</p><p>If not specified, the default time base must be considered to be
+<code>media</code>.</p><p>A <code>ttp:timeBase</code> attribute is considered to be significant only
+when specified on the <code>tt</code> element.</p><p>When operating with either <code>media</code> or <code>smpte</code>
+time bases, a diachronic presentation of a <a href="#terms-document-instance">document instance</a> may
+be subject to transformations of the controlling time line, such as
+temporal reversal, dilation (expansion), or constriction
+(compression); however, when operating with the <code>clock</code>
+time base, no transformations are permitted, and diachronic
+presentation proceeds on a linear, monotonically increasing time line
+based on the passage of real time.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Due to there being only one time base parameter that applies to a
+given <a href="#terms-document-instance">document instance</a>, the interpretation of time expressions
+is uniform throughout the <a href="#terms-document-instance">document instance</a>.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#time-expression-semantics"><b>H Time Expression Semantics</b></a> for further details
+on the interpretation of time expressions according to the designated time base.</p></div></div></div></div><div class="div1">
+<h2><a id="content"></a>8 Content</h2><p>This section specifies the <em>content</em> matter of the core
+vocabulary catalog.</p><div class="div2">
+<h3><a id="content-element-vocabulary"></a>8.1 Content Element Vocabulary</h3><p>The following elements specify the structure and principal content aspects of a
+<a href="#terms-document-instance">document instance</a>:</p><ul><li><p><a href="#document-structure-vocabulary-tt"><b>8.1.1 tt</b></a></p></li><li><p><a href="#document-structure-vocabulary-head"><b>8.1.2 head</b></a></p></li><li><p><a href="#document-structure-vocabulary-body"><b>8.1.3 body</b></a></p></li><li><p><a href="#content-vocabulary-div"><b>8.1.4 div</b></a></p></li><li><p><a href="#content-vocabulary-p"><b>8.1.5 p</b></a></p></li><li><p><a href="#content-vocabulary-span"><b>8.1.6 span</b></a></p></li><li><p><a href="#content-vocabulary-br"><b>8.1.7 br</b></a></p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>The sub-sections of this section are ordered logically (from highest to lowest level construct).</p></div><div class="div3">
+<h4><a id="document-structure-vocabulary-tt"></a>8.1.1 tt</h4><p>The <code>tt</code> element serves as the root document element of a <a href="#terms-document-instance">document instance</a>.</p><p>The <code>tt</code> element accepts as its children zero or one <code>head</code> element followed by
+zero or one <code>body</code> element.</p><a id="elt-syntax-tt"></a><table class="syntax"><caption>XML Representation – Element Information Item: tt</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#style-attribute-extent">tts:extent</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#style-attribute-position">tts:position</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang"><span class="reqattr">xml:lang</span></a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>) : default
+  {<em>any attribute in TT Parameter namespace</em>}
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#document-structure-vocabulary-head">head</a>?, <a href="#document-structure-vocabulary-body">body</a>?
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p>The <a href="#terms-root-temporal-extent">root temporal extent</a>, i.e., the time interval over which a <a href="#terms-document-instance">document instance</a> is active, has an implicit duration that is equal to the
+implicit duration of the <code>body</code> element of the document, if the <code>body</code> element is present, or zero, if the <code>body</code> element is absent.</p><p>If the <a href="#style-attribute-extent"><code>tts:extent</code></a> attribute is specified on the <code>tt</code>
+element, then it must adhere to <a href="#style-attribute-extent"><b>10.2.11 tts:extent</b></a>, in which case it
+specifies the spatial extent of the <a href="#terms-root-container-region">root container region</a> in
+which <a href="#terms-content-region">content regions</a> are located and presented. If no <code>tts:extent</code>
+attribute is specified, then the spatial extent of the <a href="#terms-root-container-region">root container region</a> is
+considered to be determined by the <a href="#terms-document-processing-context">document processing context</a>.
+The origin of the <a href="#terms-root-container-region">root container region</a> is determined by the <a href="#terms-document-processing-context">document processing context</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In the absence of other requirements, and if a <a href="#terms-related-media-object">related media object</a> exists, then it is recommended
+that the <a href="#terms-document-processing-context">document processing context</a> determine that:</p><ul><li><p>if no <code>tts:extent</code> is specified on the root <code>tt</code> element, the extent of the <a href="#terms-root-container-region">root container region</a> be
+established as equal to the extent of the <a href="#terms-related-media-object-region">related media object region</a>; and</p></li><li><p>the origin of the <a href="#terms-root-container-region">root container region</a> be established so that this region is centered in the
+<a href="#terms-related-media-object-region">related media object region</a>.</p></li></ul></div><div class="note"><p class="prefix"><b>Note:</b></p><p>If an author desires to signal the (storage or image) aspect ratio of the <a href="#terms-root-container-region">root container region</a>
+without specifying its resolution, then this may be accomplished by using metadata specified
+in an external namespace, such as <code>m708:aspectRatio</code> as defined in <a href="#smpte2052">[SMPTE 2052-11]</a>, §5.4.4.
+This would permit, for example, the interchange of information that reflects the
+the semantics of <a href="#cea708e">[CEA-708-E]</a> , §4.5 “Caption Service Metadata”, “ASPECT RATIO”.</p></div><p>If the <a href="#style-attribute-position"><code>tts:position</code></a> attribute is specified on the <code>tt</code>
+element, then it must adhere to <a href="#style-attribute-position"><b>10.2.27 tts:position</b></a>, in which case it
+specifies the position of the <a href="#terms-root-container-region">root container region</a> relative to a reference positioning area.</p><p>Except for the <code>tts:extent</code> and <code>tts:position</code> attributes described above, an attribute in the TT Style Namespace should not
+be specified on the <code>tt</code> element unless it denotes an inheritable style property, in which case such inheritable style property is available
+for <a href="#semantics-style-inheritance-root">root style inheritance</a>. If a non-inheritable style property is specified, then
+it must be ignored for the purpose of non-validation processing. In the case of validation
+processing, such usage should be reported as a warning, or, if strict validation is performed, as an error.</p><p>An <code>xml:lang</code> attribute must be specified on the <code>tt</code> element.
+If the attribute value is empty, it signifies that there is no default language that applies
+to the text contained within the <a href="#terms-document-instance">document instance</a>.</p><p>If no <code>xml:space</code> attribute is specified upon the <code>tt</code> element, then it must
+be considered as if the attribute had been specified with a value of <code>default</code>.</p></div><div class="div3">
+<h4><a id="document-structure-vocabulary-head"></a>8.1.2 head</h4><p>The <code>head</code> element is a container element used to group header matter, including metadata,
+profile, embedded content resources, styling, and layout information.</p><p>The <code>head</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more elements in the
+<a href="#element-vocab-group-profile"><code>Profile.class</code></a> element group,
+followed by zero or one <a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element,
+followed by zero or one <a href="#styling-vocabulary-styling"><code>styling</code></a> element,
+followed by zero or one <a href="#layout-vocabulary-layout"><code>layout</code></a> element,
+followed by zero or one <a href="#animation-vocabulary-animation"><code>animation</code></a> element.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
+element group applies semantically to the <a href="#terms-document-instance">document instance</a> as a
+whole, and not just the <code>head</code> element.</p><p>Any parameters specified by children in the <code>Parameters.class</code>
+element group applies semantically to the <a href="#terms-document-instance">document instance</a> as a
+whole, and not just the <code>head</code> element.</p><p>A <code>resources</code> child element is used to specify embedded content constructs
+that are referenced from certain style constructs and
+<a href="#terms-embedded-content-element">embedded content elements</a>.</p><p>A <code>styling</code> child element is used to specify style constructs
+that are referenced from other style constructs, by layout constructs, and by
+<a href="#terms-content-element">content elements</a>.</p><p>A <code>layout</code> child element is used to specify layout constructs that
+are referenced by <a href="#terms-content-element">content elements</a>.</p><p>An <code>animation</code> child element is used to specify animation constructs that
+target animatable <a href="#terms-content-element">content element</a>
+or <a href="#element-vocab-type-layout">Layout</a> elements.</p><a id="elt-syntax-head"></a><table class="syntax"><caption>XML Representation – Element Information Item: head</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;head
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-profile">Profile.class</a>*, <a href="#embedded-content-vocabulary-resources">resources</a>?, <a href="#styling-vocabulary-styling">styling</a>?, <a href="#layout-vocabulary-layout">layout</a>?, <a href="#animation-vocabulary-animation">animation</a>?
+&lt;/head&gt;
+</pre></div>
+</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
+<code>head</code> element, the implied time interval of this element is
+defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div><div class="div3">
+<h4><a id="document-structure-vocabulary-body"></a>8.1.3 body</h4><p>The <code>body</code> element functions as a logical container and a temporal
+structuring element for a sequence of textual content units represented as
+logical divisions.</p><p>The <code>body</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more
+elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
+followed by
+zero or more <code>div</code> elements.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
+element group applies semantically to the <code>body</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
+element group apply semantically to the <code>body</code> element.</p><a id="elt-syntax-body"></a><table class="syntax"><caption>XML Representation – Element Information Item: body</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;body
+  <a href="#animation-attribute-animate">animate</a> = IDREFS
+  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#layout-attribute-region">region</a> = IDREF
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Metadata namespace</em>}
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, <a href="#content-vocabulary-div">div</a>*
+&lt;/body&gt;
+</pre></div>
+</td></tr></tbody></table><p>An author may specify a temporal interval for a <code>body</code> element using
+the <code>begin</code>, <code>dur</code>, and <code>end</code> attributes. If the begin point
+of this interval remains unspecified, then the begin point is interpreted as the beginning
+point of the <a href="#terms-root-temporal-extent">root temporal extent</a>. Similarly, if the end point of this interval remains unspecified, then the
+end point is interpreted as the ending point of the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <a href="#terms-document-instance">document instance</a> referenced from a SMIL presentation
+is expected to follow the same timing rules as apply to other SMIL media
+objects.</p></div><p>If relative begin or end times are specified on the <code>body</code>
+element, then these times are resolved by reference to the beginning and
+ending time of the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p><p>If the <a href="#terms-root-temporal-extent">root temporal extent</a> is shorter than the computed duration of the
+<code>body</code> element, then the active time interval of a <code>body</code> element is
+truncated to the active end point of the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p><p>An author may associate a set of style properties with a
+<code>body</code> element by means of either the <code>style</code>
+attribute or inline style attributes or a combination thereof.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Style properties that are associated with a <code>body</code> element
+in a <a href="#terms-document-instance">document instance</a> are available for style inheritance by
+descendant <a href="#terms-content-element">content elements</a> such as <code>div</code>, <code>p</code>,
+<code>span</code>
+and <code>br</code>.</p></div><p>If no <code>timeContainer</code> attribute is specified on a
+<code>body</code> element, then it must be interpreted as having
+<em>parallel</em>
+time containment semantics.</p></div><div class="div3">
+<h4><a id="content-vocabulary-div"></a>8.1.4 div</h4><p>The <code>div</code> element functions as a logical container and a temporal
+structuring element for a sequence of textual content units represented as
+logical sub-divisions or paragraphs.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When rendered on a continuous (non-paged) visual presentation medium,
+a <code>div</code> element is expected to generate
+one or more block
+areas
+that contain zero or more child block areas
+generated by the <code>div</code> element's
+descendant
+<code>p</code> elements.
+</p><p>If some
+block area generated by a <code>div</code> element does
+not contain any child areas, then it is not expected to be presented.</p></div><p>The <code>div</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more
+elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
+followed by zero or one
+element in the <a href="#element-vocab-group-layout"><code>Layout.class</code></a> element group,
+followed by zero or more elements in the <a href="#element-vocab-group-block"><code>Block.class</code></a> or
+<a href="#element-vocab-group-embedded"><code>Embedded.class</code></a> element groups.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
+element group applies semantically to the <code>div</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
+element group apply semantically to the <code>div</code> element.</p><a id="elt-syntax-div"></a><table class="syntax"><caption>XML Representation – Element Information Item: div</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;div
+  <a href="#animation-attribute-animate">animate</a> = IDREFS
+  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#layout-attribute-region">region</a> = IDREF
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Metadata namespace</em>}
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, <a href="#element-vocab-group-layout">Layout.class</a>?, (<a href="#element-vocab-group-block">Block.class</a>|<a href="#element-vocab-group-embedded">Embedded.class</a>)*
+&lt;/div&gt;
+</pre></div>
+</td></tr></tbody></table><p>An author may associate a set of style properties with a <code>div</code> element by means of either
+the <code>style</code> attribute or inline style attributes or a combination thereof.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Style properties that are associated
+with
+a <code>div</code> element in a <a href="#terms-document-instance">document instance</a>
+are available for style inheritance by descendant <a href="#terms-content-element">content elements</a> such as
+<code>div</code>, 
+<code>p</code>,
+<code>span</code>, and
+<code>br</code>.</p></div><p>If a
+<a href="#style-attribute-position"><code>tts:extent</code></a>,
+<a href="#style-attribute-position"><code>tts:origin</code></a>, or
+<a href="#style-attribute-position"><code>tts:position</code></a>
+style attribute is specified on a <code>div</code> element, then that specification must be considered to be
+equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>div</code> element, where the
+extent, origin, or position of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
+value of the respective attribute. If any of these style attributes are specified,
+then they apply to the same <a href="#terms-implied-inline-region">implied inline region</a>.
+If both <a href="#style-attribute-position"><code>tts:origin</code></a> and <a href="#style-attribute-position"><code>tts:position</code></a> attributes
+are specified and <a href="#style-attribute-position"><code>tts:position</code></a> is a supported property,
+then the <a href="#style-attribute-position"><code>tts:origin</code></a> attribute must be ignored when constructing the associated
+<a href="#terms-implied-inline-region">implied inline region</a>.</p><p>If no <code>timeContainer</code> attribute is specified on
+a <code>div</code> element, then it must be interpreted as having
+<em>parallel</em> time containment semantics.</p></div><div class="div3">
+<h4><a id="content-vocabulary-p"></a>8.1.5 p</h4><p>A <code>p</code> element represents a logical paragraph, serving as
+a transition between block level and inline level formatting semantics.</p><p>The <code>p</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more
+elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
+followed by zero or one
+element in the <a href="#element-vocab-group-layout"><code>Layout.class</code></a> element group,
+followed by zero or more elements in the <a href="#element-vocab-group-inline"><code>Inline.class</code></a> or
+<a href="#element-vocab-group-embedded"><code>Embedded.class</code></a> element groups.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
+element group applies semantically to the <code>p</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
+element group apply semantically to the <code>p</code> element.</p><a id="elt-syntax-p"></a><table class="syntax"><caption>XML Representation – Element Information Item: p</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;p
+  <a href="#animation-attribute-animate">animate</a> = IDREFS
+  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#layout-attribute-region">region</a> = IDREF
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Metadata namespace</em>}
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, <a href="#element-vocab-group-layout">Layout.class</a>?, (<a href="#element-vocab-group-inline">Inline.class</a>|<a href="#element-vocab-group-embedded">Embedded.class</a>)*
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p>An author may associate a set of style properties with a
+<code>p</code> element by means of either the <code>style</code>
+attribute or inline style attributes or a combination thereof.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Style properties that are associated with a <code>p</code> element
+in a <a href="#terms-document-instance">document instance</a> are available for style inheritance by
+descendant <a href="#terms-content-element">content elements</a> such as <code>span</code> and
+<code>br</code>.</p></div><p>If a
+<a href="#style-attribute-position"><code>tts:extent</code></a>,
+<a href="#style-attribute-position"><code>tts:origin</code></a>, or
+<a href="#style-attribute-position"><code>tts:position</code></a>
+style attribute is specified on a <code>p</code> element, then that specification must be considered to be
+equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>p</code> element, where the
+extent, origin, or position of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
+value of the respective attribute. If any of these style attributes are specified,
+then they apply to the same <a href="#terms-implied-inline-region">implied inline region</a>.
+If both <a href="#style-attribute-position"><code>tts:origin</code></a> and <a href="#style-attribute-position"><code>tts:position</code></a> attributes
+are specified and <a href="#style-attribute-position"><code>tts:position</code></a> is a supported property,
+then the <a href="#style-attribute-position"><code>tts:origin</code></a> attribute must be ignored when constructing the associated
+<a href="#terms-implied-inline-region">implied inline region</a>.</p><p>If no <code>timeContainer</code> attribute is specified on
+a <code>p</code> element, then it must be interpreted as having
+<em>parallel</em> time containment semantics.</p><p>If a sequence of children of a <code>p</code> element
+consists solely of <a href="#terms-character-information-item">character information items</a>, then that sequence must
+be considered to be an <em>anonymous span</em> for the purpose of
+applying style properties that apply to <code>span</code> elements.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The presentation semantics of TTML effectively
+implies that a <code>p</code> element constitutes a line break. In particular,
+it is associated with a block-stacking constraint both before the first
+generated line area and after the last generated line area. See
+<a href="#semantics-region-layout-step-2"><b>11.3.1.4 Synchronic Flow Processing</b></a> for further details.</p></div></div><div class="div3">
+<h4><a id="content-vocabulary-span"></a>8.1.6 span</h4><p>The <code>span</code> element functions as a logical container and a temporal
+structuring element for a sequence of textual content units having inline
+level formatting semantics.</p><p>When presented on a visual medium, a <code>span</code> element is intended to
+generate a sequence of inline areas, each containing one or more glyph areas.</p><p>The <code>span</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more
+elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
+followed by zero or more elements in the <a href="#element-vocab-group-inline"><code>Inline.class</code></a> or
+<a href="#element-vocab-group-embedded"><code>Embedded.class</code></a> element groups.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
+element group applies semantically to the <code>span</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
+element group apply semantically to the <code>span</code> element.</p><a id="elt-syntax-span"></a><table class="syntax"><caption>XML Representation – Element Information Item: span</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;span
+  <a href="#animation-attribute-animate">animate</a> = IDREFS
+  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#layout-attribute-region">region</a> = IDREF
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
+  <a href="#content-attribute-xlink-arcrole">xlink:arcrole</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>+
+  <a href="#content-attribute-xlink-href">xlink:href</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+  <a href="#content-attribute-xlink-role">xlink:role</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>+
+  <a href="#content-attribute-xlink-show">xlink:show</a> = (<em>new</em>|<em>replace</em>|<em>embed</em>|<em>other</em>|<em>none</em>) : new
+  <a href="#content-attribute-xlink-title">xlink:title</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Metadata namespace</em>}
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, (<a href="#element-vocab-group-inline">Inline.class</a>|<a href="#element-vocab-group-embedded">Embedded.class</a>)*
+&lt;/span&gt;
+</pre></div>
+</td></tr></tbody></table><p>An author may associate a set of style properties with a
+<code>span</code> element by means of either the <code>style</code>
+attribute or inline style attributes or a combination thereof.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Style properties that are associated with a <code>span</code> element
+in a <a href="#terms-document-instance">document instance</a> are available for style inheritance by
+descendant <a href="#terms-content-element">content elements</a> such as <code>span</code> and
+<code>br</code>.</p></div><p>If no <code>timeContainer</code> attribute is specified on
+a <code>span</code> element, then it must be interpreted as having
+<em>parallel</em> time containment semantics.</p><p>The linking attributes <code>xlink:*</code> may be used to link a <code>span</code> element with related content, using the
+specified location (<code>href</code>), roles, and title. The behavior of link activation is affected by the <code>xlink:show</code> attribute,
+the precise meaning of which is determined by the <a href="#terms-document-processing-context">document processing context</a>.</p><p>If a <code>span</code> element specifies an <code>xlink:href</code> attribute, then a nested <code>span</code> element descendant must not specify
+an <code>xlink:href</code> attribute, and, if it does, then the latter must be ignored for the purpose of presentation or activation processing.</p></div><div class="div3">
+<h4><a id="content-vocabulary-br"></a>8.1.7 br</h4><p>The <code>br</code> element denotes an explicit line break.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
+element group applies semantically to the <code>br</code> element and its descendants as a whole.</p><p>Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
+element group apply semantically to the <code>br</code> element.</p><a id="elt-syntax-br"></a><table class="syntax"><caption>XML Representation – Element Information Item: br</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;br
+  <a href="#animation-attribute-animate">animate</a> = IDREFS
+  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#layout-attribute-region">region</a> = IDREF
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Metadata namespace</em>}
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*
+&lt;/br&gt;
+</pre></div>
+</td></tr></tbody></table><p>When presented on a visual medium, the presence of a <code>br</code> element must be
+interpreted as a forced line break.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The visual presentation of a <code>br</code> element is
+intended to produce the same effect as the control character
+<code>CR</code> (U+000D)
+followed by the control code <code>LF</code> (U+000A) when presented on a teletype device.
+Therefore, two <code>br</code> elements in sequence will produce a
+different effect than a single <code>br</code> element.</p></div><p>If no <code>timeContainer</code> attribute is specified on
+a <code>br</code> element, then it must be interpreted as having
+<em>parallel</em> time containment semantics.</p></div></div><div class="div2">
+<h3><a id="content-attribute-vocabulary"></a>8.2 Content Attribute Vocabulary</h3><p>This section defines the following common attributes used with many or all element types
+in the core vocabulary catalog:</p><ul><li><p><a href="#content-attribute-condition"><b>8.2.1 condition</b></a></p></li><li><p><a href="#content-attribute-xml-id"><b>8.2.7 xml:id</b></a></p></li><li><p><a href="#content-attribute-xml-lang"><b>8.2.8 xml:lang</b></a></p></li><li><p><a href="#content-attribute-xml-space"><b>8.2.9 xml:space</b></a></p></li></ul><p>In addition, this section defines the following linking vocabulary used by certain element types
+in the core vocabulary catalog:</p><ul><li><p><a href="#content-attribute-xlink-arcrole"><b>8.2.2 xlink:arcrole</b></a></p></li><li><p><a href="#content-attribute-xlink-href"><b>8.2.3 xlink:href</b></a></p></li><li><p><a href="#content-attribute-xlink-role"><b>8.2.4 xlink:role</b></a></p></li><li><p><a href="#content-attribute-xlink-show"><b>8.2.5 xlink:show</b></a></p></li><li><p><a href="#content-attribute-xlink-title"><b>8.2.6 xlink:title</b></a></p></li></ul><div class="div3">
+<h4><a id="content-attribute-condition"></a>8.2.1 condition</h4><p>The <code>condition</code> attribute is used to conditionally exclude an element from semantic processing.</p><p>The <code>condition</code> attribute may be used with any element in the core vocabulary catalog
+except profile matter, i.e., elements of the <a href="#element-vocab-type-profile">Profile Module</a>.</p><p>The value of a <code>condition</code> attribute must adhere to a
+<a href="#content-value-condition">&lt;condition&gt;</a> expression.</p><p>For the purpose of presentation processing, if an element specifies a <code>condition</code> attribute, and the
+its <a href="#content-value-condition">&lt;condition&gt;</a> expression value evaluates to <code>false</code>,
+then the semantics of the element and its descendant elements must be ignored.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, if a <a href="#content-vocabulary-p"><code>p</code></a> element specifies a <code>condition</code>
+attribute that evaluates to <code>false</code>, then the content of that element is ignored for presentation purposes.</p></div></div><div class="div3">
+<h4><a id="content-attribute-xlink-arcrole"></a>8.2.2 xlink:arcrole</h4><p>The <code>xlink:arcrole</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:arcrole</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
+<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
+<h4><a id="content-attribute-xlink-href"></a>8.2.3 xlink:href</h4><p>The <code>xlink:href</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:href</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
+<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
+<h4><a id="content-attribute-xlink-role"></a>8.2.4 xlink:role</h4><p>The <code>xlink:role</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:role</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
+<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
+<h4><a id="content-attribute-xlink-show"></a>8.2.5 xlink:show</h4><p>The <code>xlink:show</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:show</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
+<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
+<h4><a id="content-attribute-xlink-title"></a>8.2.6 xlink:title</h4><p>The <code>xlink:title</code> attribute is used as defined by <a href="#xlink11">[XLink 1.1]</a>.</p><p>The <code>xlink:title</code> attribute may be used with any <a href="#content-vocabulary-span"><code>span</code></a> or
+<a href="#embedded-content-vocabulary-image"><code>image</code></a> element.</p></div><div class="div3">
+<h4><a id="content-attribute-xml-id"></a>8.2.7 xml:id</h4><p>The <code>xml:id</code> attribute is used as defined by
+<a href="#xmlid">[XML ID]</a>.</p><p>The <code>xml:id</code> attribute may be used with any element in the core vocabulary catalog.</p></div><div class="div3">
+<h4><a id="content-attribute-xml-lang"></a>8.2.8 xml:lang</h4><p>The <code>xml:lang</code> attribute is used as defined by
+<a href="#xml10">[XML 1.0]</a>, §2.12, <em>Language Identification</em>.</p><p>The <code>xml:lang</code> attribute must be specified on the <code>tt</code>
+element and may be specified by an instance of any other element type
+in the core vocabulary catalog except parameter vocabulary.</p></div><div class="div3">
+<h4><a id="content-attribute-xml-space"></a>8.2.9 xml:space</h4><p>The <code>xml:space</code> attribute is used as defined by
+<a href="#xml10">[XML 1.0]</a>, §2.10, <em>White Space Handling</em>.</p><p>The <code>xml:space</code> attribute may be used with any element in
+the core vocabulary catalog except parameter vocabulary.</p><p>The semantics of the value <code>default</code> are fixed to mean that
+when performing presentation processing of a <a href="#terms-document-instance">document instance</a> as
+described by <a href="#semantics-region-layout-step-2"><b>11.3.1.4 Synchronic Flow Processing</b></a>,
+processing must occur as
+if the following properties were specified on the affected
+elements of an equivalent intermediate XSL-FO document:</p><ul><li><p><code>suppress-at-line-break="auto"</code></p></li><li><p><code>linefeed-treatment="treat-as-space"</code></p></li><li><p><code>white-space-collapse="true"</code></p></li><li><p><code>white-space-treatment="ignore-if-surrounding-linefeed"</code></p></li></ul><p>Similarly, the semantics of the value <code>preserve</code> are fixed to mean that
+when performing presentation processing, processing must occur as
+if the following properties were specified on the affected
+elements of an equivalent intermediate XSL-FO document:
+</p><ul><li><p><code>suppress-at-line-break="retain"</code></p></li><li><p><code>linefeed-treatment="preserve"</code></p></li><li><p><code>white-space-collapse="false"</code></p></li><li><p><code>white-space-treatment="preserve"</code></p></li></ul><p>When performing other types of processing intended to eventually
+result in a visual presentation by means other than those described
+in this specification, the semantics of space collapsing and
+preservation as described above should be respected. For other types
+of processing, the treatment of the <code>xml:space</code> attribute
+is processor dependent, but should respect the semantics described
+above if possible.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the above four cited XSL-FO properties are defined by
+by <a href="#xsl11">[XSL 1.1]</a>, § 7.17.3, 7.16.7, 7.16.12, and 7.16.8, respectively.</p></div></div></div><div class="div2">
+<h3><a id="content-value-expressions"></a>8.3 Content Value Expressions</h3><p>Core vocabulary may make use of the following expressions:</p><ul><li><p><a href="#content-value-arguments"><b>8.3.1 &lt;arguments&gt;</b></a></p></li><li><p><a href="#content-value-bound-parameter"><b>8.3.2 &lt;bound-parameter&gt;</b></a></p></li><li><p><a href="#content-value-condition"><b>8.3.3 &lt;condition&gt;</b></a></p></li><li><p><a href="#content-value-condition-function"><b>8.3.4 &lt;condition-function&gt;</b></a></p></li><li><p><a href="#content-value-expression"><b>8.3.5 &lt;expression&gt;</b></a></p></li><li><p><a href="#content-value-media-function"><b>8.3.6 &lt;media-function&gt;</b></a></p></li><li><p><a href="#content-value-parameter-function"><b>8.3.8 &lt;parameter-function&gt;</b></a></p></li><li><p><a href="#content-value-quoted-string"><b>8.3.7 &lt;quoted-string&gt;</b></a></p></li><li><p><a href="#content-value-supports-function"><b>8.3.9 &lt;supports-function&gt;</b></a></p></li></ul><div class="div3">
+<h4><a id="content-value-arguments"></a>8.3.1 &lt;arguments&gt;</h4><p>A &lt;arguments&gt; value is a sub-expression used with a <code>function-expression</code> non-terminal of an
+<a href="#content-value-expression">&lt;expression&gt;</a> value.</p><a id="arguments-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;arguments&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;arguments&gt;
+  : "(" ")"
+  | "(" argument-list ")"
+
+argument-list
+  : <a href="#content-value-expression">&lt;expression&gt;</a>
+  | argument-list "," <a href="#content-value-expression">&lt;expression&gt;</a>
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="content-value-bound-parameter"></a>8.3.2 &lt;bound-parameter&gt;</h4><p>A &lt;bound-parameter&gt; value is one of an enumerated collection of named parameters bound to a value by the
+<a href="#terms-content-processor">content processor</a>.</p><a id="bound-parameter-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;bound-parameter&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;bound-parameter&gt;
+  : forced
+  | mediaAspectRatio
+  | mediaLanguage
+  | userLanguage
+</pre></div>
+</td></tr></tbody></table><dl><dt class="label"><a id="bound-parameter-forced"></a><code>forced</code></dt><dd><p>Evaluates to a boolean value that denotes if the <a href="#terms-content-processor">content processor</a> is operating with
+<a href="#terms-forced-subtitle">forced subtitles</a> enabled.</p></dd><dt class="label"><a id="bound-parameter-mediaAspectRatio"></a><code>mediaAspectRatio</code></dt><dd><p>Evaluates to a numeric value equal to the aspect ratio of the <a href="#terms-related-media-object">related media object</a>.</p></dd><dt class="label"><a id="bound-parameter-mediaLanguage"></a><code>mediaLanguage</code></dt><dd><p>Evaluates to a string value equal to the (primary) language of the <a href="#terms-related-media-object">related media object</a>.</p></dd><dt class="label"><a id="bound-parameter-userLanguage"></a><code>userLanguage</code></dt><dd><p>Evaluates to a string value equal to the (primary) language of the user as determined by the
+<a href="#terms-document-processing-context">document processing context</a>.</p></dd></dl></div><div class="div3">
+<h4><a id="content-value-condition"></a>8.3.3 &lt;condition&gt;</h4><p>A &lt;condition&gt; value is used to specify an expression that evaluates to a binary value
+which is used to determine if the semantics of a
+<a href="#terms-conditionalized-element">conditionalized element</a> is respected or ignored during content processing.</p><a id="condition-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;condition&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;condition&gt;
+  : <a href="#content-value-expression">&lt;expression&gt;</a>
+</pre></div>
+</td></tr></tbody></table><p>If a &lt;condition&gt; value contains a <code>function-expression</code> non-terminal, then it must take the form
+of a <a href="#content-value-condition-function">&lt;condition-function&gt;</a> expression.</p></div><div class="div3">
+<h4><a id="content-value-condition-function"></a>8.3.4 &lt;condition-function&gt;</h4><p>A &lt;condition-function&gt; value is a sub-expression that may be used in a <a href="#content-value-condition">&lt;condition&gt;</a> value expression.</p><a id="condition-function-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;condition-function&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;condition-function&gt;
+  | <a href="#content-value-media-function">&lt;media-function&gt;</a>
+  | <a href="#content-value-parameter-function">&lt;parameter-function&gt;</a>
+  | <a href="#content-value-supports-function">&lt;supports-function&gt;</a>
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="content-value-expression"></a>8.3.5 &lt;expression&gt;</h4><p>An &lt;expression&gt; value is a sub-expression of a <a href="#content-value-condition">&lt;condition&gt;</a> value.</p><a id="expression-value-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;expression&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;expression&gt;
+  : logical-or-expression
+
+logical-or-expression
+  : logical-and-expression
+  | logical-or-expression "||" logical-and-expression
+
+logical-and-expression
+  : equality-expression
+  | logical-and-expression "&amp;&amp;" equality-expression
+
+equality-expression
+  : relational-expression
+  | equality-expression "==" relational-expression
+  | equality-expression "!=" relational-expression
+
+relational-expression
+  : additive-expression
+  | relational-expression "&lt;" additive-expression
+  | relational-expression "&gt;" additive-expression
+  | relational-expression "&lt;=" additive-expression
+  | relational-expression "&gt;=" additive-expression
+
+additive-expression
+  : multiplicitive-expression
+  | additive-expression "+" multiplicitive-expression
+  | additive-expression "-" multiplicitive-expression
+
+multiplicitive-expression
+  : unary-expression
+  | multiplicitive-expression "*" unary-expression
+  | multiplicitive-expression "/" unary-expression
+  | multiplicitive-expression "%" unary-expression
+
+unary-expression
+  : primary-or-function-expression
+  | "+" unary-expression
+  | "-" unary-expression
+  | "!" unary-expression
+
+primary-or-function-expression
+  : primary-expression
+  | function-expression
+
+primary-expression
+  : identifier
+  | literal
+  | "(" expression ")"
+
+function-expression
+  : identifier <a href="#content-value-arguments">&lt;arguments&gt;</a>
+
+identifier
+  : <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
+
+literal
+  : boolean-literal
+  | numeric-literal
+  | string-literal
+
+boolean-literal
+  : "true"
+  | "false"
+
+numeric-literal
+  : decimal-literal
+
+decimal-literal
+  : decimal-integer-literal "." decimal-digits? exponent-part?
+  | "." decimal-digits exponent-part?
+  | decimal-integer-literal exponent-part?
+
+decimal-integer-literal
+  : "0"
+  | non-zero-digit decimal-digits?
+
+decimal-digits
+  : decimal-digit
+  | decimal-digits decimal-digit
+
+decimal-digit
+  : "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8"
+
+non-zero-digit
+  : "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8"
+
+exponent-part
+  : exponent-indicator signed-integer
+
+exponent-indicator
+  : "e" | "E"
+
+signed-integer
+  : decimal-digits
+  | "+" decimal-digits
+  | "-" decimal-digits
+
+string-literal
+  : <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="content-value-media-function"></a>8.3.6 &lt;media-function&gt;</h4><p>A &lt;media-function&gt; value is a sub-expression that may be used in a <a href="#content-value-condition">&lt;condition&gt;</a> value expression
+in order to perform a media query on the <a href="#terms-related-media-object">related media object</a> or the
+<a href="#terms-document-processing-context">document processing context</a>.</p><a id="media-function-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;media-function&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;media-function&gt;
+  : "media" "(" media-query ")"
+
+media-query
+  : <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
+</pre></div>
+</td></tr></tbody></table><p>The <code>media-query</code> argument of a &lt;media-function&gt; value expression must adhere to
+the syntax of the <code>media_query_list</code> defined by <a href="#media-queries">[Media Queries]</a>, § 3.</p><p>A &lt;media-function&gt; value expression evaluates to <code>true</code> if the specified media query
+evaluates to <code>true</code>, otherwise, the value expression evaluates to <code>false</code>.</p></div><div class="div3">
+<h4><a id="content-value-quoted-string"></a>8.3.7 &lt;quoted-string&gt;</h4><p>A &lt;quoted-string&gt; value expression is used to specify a double or single quoted string.</p><a id="quoted-string-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;quoted-string&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;quoted-string&gt;
+  : double-quoted-string
+  | single-quoted-string
+
+double-quoted-string
+  : '"' ( [^"\\] | escape )+ '"'
+
+single-quoted-string
+  : "'" ( [^'\\] | escape )+ "'"
+
+escape
+  : '\\' <em>char</em>
+</pre></div>
+
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="content-value-parameter-function"></a>8.3.8 &lt;parameter-function&gt;</h4><p>A &lt;parameter-function&gt; value is a sub-expression that may be used in a <a href="#content-value-condition">&lt;condition&gt;</a> value expression
+in order to obtain a named parameter of the <a href="#terms-document-processing-context">document processing context</a>.</p><a id="parameter-function-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;parameter-function&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;parameter-function&gt;
+  : "parameter" "(" parameter-name ")"
+
+parameter-name
+  : <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
+</pre></div>
+</td></tr></tbody></table><p>When de-quoted, the <code>parameter-name</code> argument of a &lt;parameter-function&gt; value expression must adhere to an
+<a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>, which must, in turn, be one of the values enumerated
+by <a href="#content-value-bound-parameter">&lt;bound-parameter&gt;</a>.</p><p>A &lt;parameter-function&gt; value expression evaluates to the value associated with (bound to) the
+specified paramater name.</p></div><div class="div3">
+<h4><a id="content-value-supports-function"></a>8.3.9 &lt;supports-function&gt;</h4><p>A &lt;supports-function&gt; value is a sub-expression that may be used in a <a href="#content-value-condition">&lt;condition&gt;</a> value expression
+in order to obtain a boolean value that denotes whether a specified <a href="#terms-feature">feature</a> or <a href="#terms-extension">extension</a>
+is supported or not.</p><a id="supports-function-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;supports-function&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;supports-function&gt;
+  : "supports" "(" feature-or-extension-designator ")"
+
+feature-or-extension-designator
+  : <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
+</pre></div>
+</td></tr></tbody></table><p>The <code>feature-or-extension-designator</code> argument of a &lt;supports-function&gt; value expression must express
+a feature designation or an extension designation as defined by
+<a href="#feature-designations"><b>E.1 Feature Designations</b></a> and <a href="#extension-designations"><b>F.1 Extension Designations</b></a>, respectively, and where the
+<code>feature-namespace</code> or <code>extension-namespace</code> component of the designation is optional, and, if
+not specified, is considered to be equal to the <em>TT Feature Namespace</em> or <em>TT Extension Namespace</em>,
+respectively.</p><p>A &lt;supports-function&gt; value expression evaluates to <code>true</code> if the specified feature or extension
+designator is (semantically) supported by the <a href="#terms-content-processor">content processor</a>.</p></div></div></div><div class="div1">
+<h2><a id="embedded-content"></a>9 Embedded Content</h2><p>This section specifies the <em>embedded content</em> matter of the core
+vocabulary catalog, where, in this context,
+<em>content</em> is to be understood as data of an arbitrary content type (format)
+and <em>embedded</em> refers to the embedding (inlining) of this data or the embedding
+of a reference to external data.</p><div class="div2">
+<h3><a id="embedded-content-element-vocabulary"></a>9.1 Embedded Content Element Vocabulary</h3><p>The following elements may be used to specify embedded content:</p><ul><li><p><a href="#embedded-content-vocabulary-audio"><b>9.1.1 audio</b></a></p></li><li><p><a href="#embedded-content-vocabulary-chunk"><b>9.1.2 chunk</b></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><b>9.1.3 data</b></a></p></li><li><p><a href="#embedded-content-vocabulary-font"><b>9.1.4 font</b></a></p></li><li><p><a href="#embedded-content-vocabulary-image"><b>9.1.5 image</b></a></p></li><li><p><a href="#embedded-content-vocabulary-resources"><b>9.1.6 resources</b></a></p></li><li><p><a href="#embedded-content-vocabulary-source"><b>9.1.7 source</b></a></p></li></ul><p>The <a href="#embedded-content-vocabulary-data"><b>9.1.3 data</b></a> element serves as
+a generic container element for an <a href="#terms-embedded-data-resource">embedded data resource</a>, which may or may not be fragmented into chunks,
+in which case a data fragment is represented using the <a href="#embedded-content-vocabulary-chunk"><b>9.1.2 chunk</b></a> element.
+The <a href="#embedded-content-vocabulary-audio"><b>9.1.1 audio</b></a>,
+<a href="#embedded-content-vocabulary-font"><b>9.1.4 font</b></a>, and
+<a href="#embedded-content-vocabulary-image"><b>9.1.5 image</b></a> elements are specialized elements used to
+to reference specific types of embedded content.
+The <a href="#embedded-content-vocabulary-resources"><b>9.1.6 resources</b></a> element is used to
+group definitions of embedded content for reference by subsequent elements.
+The <a href="#embedded-content-vocabulary-source"><b>9.1.7 source</b></a> element may be used to
+express the source of embedded content.</p><div class="div3">
+<h4><a id="embedded-content-vocabulary-audio"></a>9.1.1 audio</h4><p>The <code>audio</code> element is used to define an author supplied <a href="#terms-audio-resource">audio resource</a>.</p><p>An <code>audio</code> element may appear in two contexts: (1) as a child of a <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element and
+(2) as a child of an element in the <a href="#element-vocab-group-block">Block.class</a> element group, namely, as a child of a
+<a href="#content-vocabulary-div"><code>div</code></a> or <a href="#content-vocabulary-p"><code>p</code></a> element, or
+as a child of a <a href="#content-vocabulary-span"><code>span</code></a> element. The former is referred to as an
+<a href="#terms-audio-defining-context">audio defining context</a>, the latter as an <a href="#terms-audio-presentation-context">audio presentation context</a>.</p><p>When an <code>audio</code> element appears in an <a href="#terms-audio-defining-context">audio defining context</a>, it
+serves as a sharable definition of an <a href="#terms-audio-resource">audio resource</a> that may be referenced by other <code>audio</code> elements in the
+<a href="#terms-enclosing-document-instance">enclosing document instance</a>. In this case, the active time interval of the <code>audio</code> element
+is the same as the active time interval of its parent <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A sharable definition of an <a href="#terms-audio-resource">audio resource</a> specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute in order to be referenced
+by <code>audio</code> elements in an <a href="#terms-audio-presentation-context">audio presentation context</a>.</p></div><p>When an <code>audio</code> element appears in an <a href="#terms-audio-presentation-context">audio presentation context</a>, it
+serves as a non-sharable definition of an <a href="#terms-audio-resource">audio resource</a> that implies presentation (rendering) semantics, i.e., that it is intended to be played.
+In this case, the active time interval of the <code>audio</code> element is the same as the active time interval of its parent
+<a href="#terms-content-element">content element</a>.
+</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A non-sharable definition of an <a href="#terms-audio-resource">audio resource</a> may or may not specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute, but this
+identifier is not referenced by other <code>audio</code> elements, or, if it is, the reference is ignored.</p></div><p>The <code>audio</code> element accepts as its children
+zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by zero or more
+<a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><a id="elt-syntax-audio"></a><table class="syntax"><caption>XML Representation – Element Information Item: audio</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;audio
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-audio-format">&lt;audio-format&gt;</a>
+  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-audio">&lt;audio&gt;</a>
+  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute in TT Metadata namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-source">source</a>*
+&lt;/audio&gt;
+</pre></div>
+</td></tr></tbody></table><p>An <code>audio</code> element defines an <a href="#terms-audio-resource">audio resource</a> either (1) by referring to an <a href="#terms-external-data-resource">external data resource</a>
+or (2) defining or referring to an <a href="#terms-embedded-data-resource">embedded data resource</a>, where the <a href="#terms-data-resource">data resource</a>
+contains audio content.</p><p>If an <code>audio</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must not specify a
+child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element. Conversely,
+if an <code>audio</code> element does not specify a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must specify one or more
+child <a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><p>If an <code>audio</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute and its value does not refer to a fragment of the
+<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then it should specify a
+a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute, in which case the value of the
+<a href="#embedded-content-attribute-type"><code>type</code></a> attribute must correspond with the media (content) type
+of the referenced resource. Otherwise, a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must not be specified.</p><p>If a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute is not specified or is specified as a generic type, such as <code>application/octet-stream</code>,
+and additional format information is known about a referenced <a href="#terms-audio-resource">audio resource</a>, then a <a href="#embedded-content-attribute-format"><code>format</code></a> attribute should be specified as a hint to the
+content processor.</p><p>If an <code>audio</code> element includes a child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element, then
+the <a href="#embedded-content-attribute-format"><code>format</code></a> attribute of the <code>source</code> child, if specified, must adhere to the <a href="#embedded-content-value-audio-format">&lt;audio-format&gt;</a>
+value expression.</p><p>The use of the <code>audio</code> element is illustrated by the following example.</p><a id="embedded-content-vocabulary-audio-example-1"></a><table class="example"><caption>Example Fragment – External Audio Resource</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;audio src="http://example.com/audio/description.mp3" type="audio/mp3"/&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p></div><div class="div3">
+<h4><a id="embedded-content-vocabulary-chunk"></a>9.1.2 chunk</h4><p>The <code>chunk</code> element is used to represent a distinct chunk (fragment) of data.</p><p>A <code>chunk</code> element may appear as a child of a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element.</p><a id="elt-syntax-chunk"></a><table class="syntax"><caption>XML Representation – Element Information Item: chunk</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;chunk
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#embedded-content-attribute-encoding">encoding</a> = (base16|base32|base32hex|base64|base64url) : base64
+  length = <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA
+&lt;/chunk&gt;
+</pre></div>
+</td></tr></tbody></table><p>If an <a href="#embedded-content-attribute-encoding"><code>encoding</code></a> attribute is specified, then it must denote the actual encoding of the byte sequence represented by the
+<code>chunk</code> element. If no <a href="#embedded-content-attribute-encoding"><code>encoding</code></a> attribute is specified, then the encoding must be considered to be <code>base64</code>.</p><p>If a <code>length</code> attribute is specified, then it must denote the number of decoded bytes in the byte sequence represented by the
+<code>chunk</code> element. When decoding, if a specified length value does not match the number of decoded bytes, then the chunk and its container <code>data</code>
+element must return a zero length byte sequence.
+If no <code>length</code> attribute is specified, then the chunk is considered to have a length equal to the actual number of decoded bytes.</p><p>The use of chunked data is illustrated by the following example.</p><a id="embedded-content-vocabulary-chunk-example-1"></a><table class="example"><caption>Example Fragment – Chunked Data</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;data type="text/plain; charset=us-ascii" length="44"&gt;
+  &lt;chunk length="19"&gt;
+    VGhlIHF1aWNrIGJyb3duIGZveA==
+  &lt;/chunk&gt;
+  &lt;chunk length="25"&gt;
+    IGp1bXBzIG92ZXIgdGhlIGxhenkgZG9nLg==
+  &lt;/chunk&gt;
+&lt;/data&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p></div><div class="div3">
+<h4><a id="embedded-content-vocabulary-data"></a>9.1.3 data</h4><p>The <code>data</code> element functions as a generic container for or reference to arbitrary data.</p><p>A <code>data</code> element may appear in three contexts:
+(1) as a child of a <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element,
+referred to as a <a href="#terms-data-defining-context">data defining context</a>,
+(2) as a child of a <a href="#metadata-vocabulary-metadata"><code>metadata</code></a> element,
+referred to as a <a href="#terms-data-binding-context-for-metadata">data binding context for metadata</a>, or
+(3) as a child of a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element,
+referred to as a <a href="#terms-data-binding-context-for-source">data binding context for source</a>,
+and where these latter two contexts are referred to collectively as <a href="#terms-data-binding-context">data binding contexts</a>.</p><p>When a <code>data</code> element appears in a <a href="#terms-data-defining-context">data defining context</a>, it
+serves as a sharable definition of a data resource that may be referenced by the <a href="#embedded-content-attribute-src"><code>src</code></a> attribute of
+(1) another <code>data</code> element,
+(2) an <a href="#terms-embedded-content-element">embedded content element</a>, or
+(3) a <a href="#embedded-content-vocabulary-source"><code>source</code></a> element.
+In this case, the contextualized active time interval of the <code>data</code> element is the intersection of
+the active time interval of its parent <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element and
+the active time interval of its referring element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A sharable definition of a data resource specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute in order to be referenced
+by a fragment identifier used in a <a href="#terms-data-binding-context">data binding context</a>.</p></div><p>When a <code>data</code> element appears in a <a href="#terms-data-binding-context">data binding context</a>, it
+serves as a non-sharable definition of a data resource that implies binding semantics, i.e., that it is intended to bound to (associated with) its immediate context
+of reference. In this case, the active time interval of the <code>data</code> element is the same as the active time interval of its closest ancestor timed element.
+</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A non-sharable definition of a data resource may or may not specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute, but this
+identifier is not referenced in other <a href="#terms-data-binding-context">data binding contexts</a>, or, if it is, has no binding semantics.</p></div><p>The <code>data</code> element accepts one of the following three content models:
+(1) one or more text nodes (i.e., <code>#PCDATA</code>),
+(2) zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by one or more
+<a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a> elements, or
+(3) zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by one or more
+<a href="#embedded-content-vocabulary-source"><code>source</code></a> elements, where
+the first is referred to as <a href="#terms-simple-data-embedding">simple data embedding</a>,
+the second as <a href="#terms-chunked-data-embedding">chunked data embedding</a>, and
+the third as <a href="#terms-sourced-data-embedding">sourced data embedding</a>.</p><p>When <a href="#terms-simple-data-embedding">simple data embedding</a> is used, the data resource is obtained by decoding the <code>#PCDATA</code> content.
+When <a href="#terms-chunked-data-embedding">chunked data embedding</a> is used, the data resource is obtained by concatenating the byte sequences obtained by decoding each
+child <a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a> element.
+When <a href="#terms-simple-data-embedding">sourced data embedding</a> is used, the data resource is obtained from the the first resolvable
+child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element. Furthermore,
+a child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element must not
+contain a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element, but may refer to a
+<a href="#embedded-content-vocabulary-data"><code>data</code></a> element in a <a href="#terms-data-defining-context">data defining context</a>.</p><a id="elt-syntax-data"></a><table class="syntax"><caption>XML Representation – Element Information Item: data</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;data
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#embedded-content-attribute-encoding">encoding</a> = (base16|base32|base32hex|base64|base64url) : <em>see prose below</em>
+  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-data-format">&lt;data-format&gt;</a>
+  length = <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>
+  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-data">&lt;data&gt;</a>
+  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a> : <em>see prose below</em>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA | (<a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-chunk">chunk</a>+) | (<a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-source">source</a>+)
+&lt;/data&gt;
+</pre></div>
+</td></tr></tbody></table><p>If simple data embedding is used, i.e., the content of the <code>data</code> element is one or more text nodes, then an
+<a href="#embedded-content-attribute-encoding"><code>encoding</code></a> attribute
+may be specified, and, if not specified, must be considered to be <code>base64</code>.
+If chunked or sourced data embedding is used, i.e., the content of the <code>data</code> element contains any child
+<a href="#embedded-content-vocabulary-chunk">chunk</a> or <a href="#embedded-content-vocabulary-source">source</a> element, then
+an <a href="#embedded-content-attribute-encoding"><code>encoding</code></a> attribute must not be specified, and, if specified, must be ignored
+for the purpose of content processing.</p><p>If a <code>length</code> attribute is specified, then it must denote the number of decoded bytes in the byte sequence represented by the
+<code>data</code> element. When decoding, if a specified length value does not match the number of decoded bytes, then a zero length byte sequence must be returned.
+If no <code>length</code> attribute is specified, then the data resource is considered to have a length equal to the actual number of decoded bytes.
+A <code>length</code> attribute must not be specified when using sourced data embedding.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The intention of the <code>length</code> attribute is to provide a means to perform a simple integrity check on decoded data. Note that this check does not guarantee
+data integrity during transport, i.e., the data could be modified without modifying the length.</p></div><p>If simple or chunked data embedding is used, a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must be specified,
+and must correspond with the media (content) type of the data resource. In these cases, if there is no defined type, the type <code>application/octet-stream</code>
+should be used. In the case of sourced data embedding, the media (content) type of the resolved <a href="#embedded-content-vocabulary-source">source</a> element
+is used as the type.</p><p>If a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute is not specified or resolved or is specified as a generic type,
+such as <code>application/octet-stream</code>, and additional format information is known about a referenced data resource,
+then a <a href="#embedded-content-attribute-format">format</a> attribute should be specified as a hint to the content processor.</p><p>The use of simple data embedding is illustrated by the following examples.</p><a id="embedded-content-vocabulary-data-example-1"></a><table class="example"><caption>Example Fragment – Simple Data Embedding in Data Defining Context</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;head&gt;
+  &lt;resources&gt;
+    &lt;data xml:id="sharedImageData" type="image/png" length="119"&gt;
+      iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
+      YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
+    &lt;/data&gt;
+    &lt;image xml:id="sharedImage"&gt;
+      &lt;source src="#sharedImageData"/&gt;
+    &lt;/image&gt;
+  &lt;/resources&gt;
+&lt;/head&gt;
+...
+&lt;body xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;div tts:backgroundImage="#sharedImage"/&gt;
+  &lt;div tts:backgroundImage="#sharedImage"/&gt;
+&lt;/body&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-data-example-2"></a><table class="example"><caption>Example Fragment – Simple Data Embedding in Data Binding Context for Metadata</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;div&gt;
+  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+    &lt;ttm:desc&gt;caption with metadata containing tunneled CEA-608 data&lt;/ttm:desc&gt;
+    &lt;data format="http://www.smpte-ra.org/schemas/2052-1/2013/smpte-tt#cea608"&gt;
+      gIAVLJQsnSAcIJ0sHCyAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICA
+      gICAgICAgICAgICAgICAgIAVIJQgE/QT9Jehl6FU5VTlc/Rz9CBDIENhcGFw9On06e9u725zgHOA
+      lNCU0Jehl6HEVMRU1iDWIMHjwePj5ePlc3NzcyDQINDy7/Lv6uXq5eP04/QsICwgV8dXx8LIwsit
+      zq3OQ8FDwc2AzYCUcJRwlyOXI6jyqPJ1bnVubulu6W5nbmcg9CD06W3pbeW65bogNCA0IG0gbelu
+      6W6uIK4gMbUxtSBzIHPl4+XjrimuKRUslCwVL5QvgIA=
+    &lt;/data&gt;
+  &lt;/metadata&gt;
+  &lt;p&gt;Test Captions&lt;br/&gt;DTV Access Project, WGHB-NCAM&lt;br/&gt;(running time: 4min. 15sec.)&lt;/p&gt;
+&lt;/div&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-data-example-3"></a><table class="example"><caption>Example Fragment – Simple Data Embedding in Data Binding Context for Source</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;div&gt;
+  &lt;image&gt;
+    &lt;source&gt;
+      &lt;data type="image/png" length="119"&gt;
+        iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
+        YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
+      &lt;/data&gt;
+    &lt;/source&gt;
+  &lt;/image&gt;
+&lt;/div&gt;
+</pre></div>
+</td></tr></tbody></table><p></p></div><div class="div3">
+<h4><a id="embedded-content-vocabulary-font"></a>9.1.4 font</h4><p>The <code>font</code> element is used to define an author supplied <a href="#terms-font-resource">font resource</a>.</p><p>A <code>font</code> element may appear as a child of a <a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element, referred to as a
+<a href="#terms-font-defining-context">font defining context</a>.</p><p>The <code>font</code> element accepts as its children
+zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by zero or more
+<a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><a id="elt-syntax-font"></a><table class="syntax"><caption>XML Representation – Element Information Item: font</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;font
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  family = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-font-format">&lt;font-format&gt;</a>
+  range = <a href="#embedded-content-value-unicode-range">&lt;unicode-range&gt;</a>
+  style = (normal|italic|oblique)
+  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-font">&lt;font&gt;</a>
+  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  weight = (normal|bold)
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-source">source</a>*
+&lt;/font&gt;
+</pre></div>
+</td></tr></tbody></table><p>A <code>font</code> element defines a <a href="#terms-font-resource">font resource</a> either (1) by referring to an <a href="#terms-external-data-resource">external data resource</a>
+or (2) defining or referring to an <a href="#terms-embedded-data-resource">embedded data resource</a>, where the <a href="#terms-data-resource">data resource</a>
+contains font content.</p><p>If a <code>font</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must not specify a
+child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element. Conversely,
+if a <code>font</code> element does not specify a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must specify one or more
+child <a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><p>If a <code>font</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute and its value does not refer to a fragment of the
+<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then it should specify a
+a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute, in which case the value of the
+<a href="#embedded-content-attribute-type"><code>type</code></a> attribute must correspond with the media (content) type
+of the referenced resource. Otherwise, a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must not be specified.</p><p>If a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute is not specified or is specified as a generic type, such as <code>application/octet-stream</code>,
+and additional format information is known about a referenced <a href="#terms-font-resource">font resource</a>, then a <a href="#embedded-content-attribute-format"><code>format</code></a> attribute should be specified as a hint to the
+content processor.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A font format hint might be useful to a content processor to avoid accessing a <a href="#terms-font-resource">font resource</a> it knows it cannot decode.</p></div><p>If a <code>font</code> element includes a child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element, then
+the <a href="#embedded-content-attribute-format"><code>format</code></a> attribute of the <code>source</code> child, if specified, must adhere to the <a href="#embedded-content-value-font-format">&lt;font-format&gt;</a>
+value expression.</p><p>If any of the <code>family</code>, <code>range</code>, <code>style</code>, or <code>weight</code> attributes are specified, then
+they override the family name, supported character ranges, style, and weight of the actual <a href="#terms-font-resource">font resource</a>. In particular,
+if the specified attribute value(s) differ from the value(s) of these font characteristics as encoded in the <a href="#terms-font-resource">font resource</a>, then
+the specified attribute value(s) are to be used instead of the font characteristics encoded in the <a href="#terms-font-resource">font resource</a>.</p><p>If any of the <code>family</code>, <code>range</code>, <code>style</code>, or <code>weight</code> attributes are not specified, then their values
+must be considered to be equal to the value(s) of the same named font characteristics encoded in the <a href="#terms-font-resource">font resource</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Authors are advised to use subset fonts wherever possible. A subset font is a syntactically valid <a href="#terms-font-resource">font resource</a> that
+removes unreferenced glyphs and unreferenced glyph metrics. In general, a subset font is tied to a specific document, since it may have been generated
+based on the actual character content of that document.</p></div><table border="1" class="ednote" summary="Editorial note: Font Loading Semantics"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Loading Semantics</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Specify font loading semantics, making as much use as possible (by reference) of material found at
+<a href="http://dev.w3.org/csswg/css-fonts/#font-face-loading">CSS Font Module Level 3, Font Loading Guidelines</a>.</td></tr></table><p>The use of the <code>font</code> element is illustrated by the following example.</p><a id="embedded-content-vocabulary-font-example-1"></a><table class="example"><caption>Example Fragment – Font</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;head&gt;
+  &lt;resources&gt;
+    &lt;data xml:id="lastResortFont" type="application/font-woff"&gt;
+      ... <em>base64 encoded data</em> ...
+    &lt;/data&gt;
+    &lt;font family="MyFont" range="u+20-7f,u+90-9f"&gt;
+      &lt;source src="http://example.com/fonts/myfont.otf" format="opentype"/&gt;
+      &lt;source src="#lastResortFont"/&gt;
+    &lt;/font&gt;
+  &lt;/resources&gt;
+&lt;/head&gt;
+...
+&lt;p tts:fontFamily="MyFont"&gt;use my font or last resort font&lt;/p&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p></div><div class="div3">
+<h4><a id="embedded-content-vocabulary-image"></a>9.1.5 image</h4><p>The <code>image</code> element is used to define an author supplied <a href="#terms-image-resource">image resource</a>.</p><p>An <code>image</code> element may appear in two contexts: (1) as a child of a <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element and
+(2) as a child of an element in the <a href="#element-vocab-group-block">Block.class</a> element group, namely, as a child of a
+<a href="#content-vocabulary-div"><code>div</code></a> or <a href="#content-vocabulary-p"><code>p</code></a> element, or
+as a child of a <a href="#content-vocabulary-span"><code>span</code></a> element. The former is referred to as an
+<a href="#terms-image-defining-context">image defining context</a>, the latter as an <a href="#terms-image-presentation-context">image presentation context</a>.</p><p>When an <code>image</code> element appears in an <a href="#terms-image-defining-context">image defining context</a>, it
+serves as a sharable definition of an <a href="#terms-image-resource">image resource</a> that may be referenced by another <code>image</code> element or by
+a <a href="#style-attribute-backgroundImage"><code>tts:backgroundImage</code></a> style attribute
+in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>. In this case, the active time interval of the <code>image</code> element
+is the same as the active time interval of its parent <a href="#embedded-content-vocabulary-resource"><code>resource</code></a> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A sharable definition of an <a href="#terms-image-resource">image resource</a> specifies an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute in order to be referenced
+by an <code>image</code> element or by a <a href="#style-attribute-backgroundImage"><code>tts:backgroundImage</code></a> style attribute
+in an <a href="#terms-image-presentation-context">image presentation context</a>.</p></div><p>When an <code>image</code> element appears in an <a href="#terms-image-presentation-context">image presentation context</a>, it
+serves as a non-sharable definition of an <a href="#terms-image-resource">image resource</a> that implies presentation (rendering) semantics.
+In this case, the active time interval of the <code>image</code> element is the same as the active time interval of its parent
+<a href="#terms-content-element">content element</a>.
+</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A non-sharable definition of an <a href="#terms-image-resource">image resource</a> may or may not specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute, but this
+identifier is not referenced by other <code>image</code> elements, or, if it is, the reference is ignored.</p></div><p>When an <code>image</code> element appears as a child of a <a href="#contentt-vocabulary-div"><code>div</code></a> element, then its presentation
+produces a block area in which the image is rendered; i.e., a block boundary is implied before and after the <code>image</code> element. In contrast,
+when an <code>image</code> element appears as a child of a <a href="#contentt-vocabulary-p"><code>p</code></a> or <a href="#contentt-vocabulary-span"><code>span</code></a>
+element, then its presentation produces an inline area in which the image is rendered; i.e., no block boundary is implied before and after the <code>image</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In <a href="#css2">[CSS2]</a>, these semantics would correspond to an <code>image</code> element being associated with a <code>display</code> style property with a
+value of <code>block</code> or <code>inline</code>, respectively.</p></div><p>The presentation of an <a href="#terms-image-resource">image resource</a> referenced by a
+<a href="#style-attribute-backgroundImage"><code>tts:backgroundImage</code></a> style attribute must not affect content layout.</p><p>The <code>image</code> element accepts as its children
+zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by zero or more
+<a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><a id="elt-syntax-image"></a><table class="syntax"><caption>XML Representation – Element Information Item: image</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;image
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-image-format">&lt;image-format&gt;</a>
+  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-image">&lt;image&gt;</a>
+  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xlink-arcrole">xlink:arcrole</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>+
+  <a href="#content-attribute-xlink-href">xlink:href</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+  <a href="#content-attribute-xlink-role">xlink:role</a> = <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>+
+  <a href="#content-attribute-xlink-show">xlink:show</a> = (<em>new</em>|<em>replace</em>|<em>embed</em>|<em>other</em>|<em>none</em>) : new
+  <a href="#content-attribute-xlink-title">xlink:title</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute in TT Metadata namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-source">source</a>*
+&lt;/image&gt;
+</pre></div>
+</td></tr></tbody></table><p>An <code>image</code> element defines an <a href="#terms-image-resource">image resource</a> either (1) by referring to an <a href="#terms-external-data-resource">external data resource</a>
+or (2) defining or referring to an <a href="#terms-embedded-data-resource">embedded data resource</a>, where the <a href="#terms-data-resource">data resource</a>
+contains image content.</p><p>If an <code>image</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must not specify a
+child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element. Conversely,
+if an <code>image</code> element does not specify a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must specify one or more
+child <a href="#embedded-content-vocabulary-source"><code>source</code></a> elements.</p><p>If an <code>image</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute and its value does not refer to a fragment of the
+<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then it should specify a
+a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute, in which case the value of the
+<a href="#embedded-content-attribute-type"><code>type</code></a> attribute must correspond with the media (content) type
+of the referenced resource. Otherwise, a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must not be specified.</p><p>If a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute is not specified or is specified as a generic type, such as <code>application/octet-stream</code>,
+and additional format information is known about a referenced <a href="#terms-image-resource">image resource</a>, then a <a href="#embedded-content-attribute-format"><code>format</code></a> attribute should be specified as a hint to the
+content processor.</p><p>If an <code>image</code> element includes a child <a href="#embedded-content-vocabulary-source"><code>source</code></a> element, then
+the <a href="#embedded-content-attribute-format"><code>format</code></a> attribute of the <code>source</code> child, if specified, must adhere to the <a href="#embedded-content-value-image-format">&lt;image-format&gt;</a>
+value expression.</p><p>An <code>image</code> element may specify either (both)
+<a href="#style-attribute-width"><code>tts:width</code></a> or (and) 
+<a href="#style-attribute-height"><code>tts:height</code></a> style attributes in order to specify the presentation width or height of the image when
+intrinsic width or height information is not available or is intended to be overridden. If (either or both of) these attributes are specified on both an
+<code>image</code> element in an <a href="#terms-image-presentation-context">image presentation context</a> and on the
+<code>image</code> element in an <a href="#terms-image-defining-context">image defining context</a> to which the former refers, then
+these attributes specified on the former take precedence over those specified on the latter.</p><p>The linking attributes <code>xlink:*</code> may be used to link an <code>image</code> element with related content, using the
+specified location (<code>href</code>), roles, and title. The behavior of link activation is affected by the <code>xlink:show</code> attribute,
+the precise meaning of which is determined by the <a href="#terms-document-processing-context">document processing context</a>.</p><p>The use of the <code>image</code> element is illustrated by the following examples.</p><a id="embedded-content-vocabulary-image-example-1"></a><table class="example"><caption>Example Fragment – External Image Resources</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;div&gt;
+  &lt;p&gt;This division has a content image that appears as a block area after this paragraph.&lt;/p&gt;
+  &lt;image src="http://example.com/images/caption.png" type="image/png"/&gt;
+&lt;div&gt;
+...
+&lt;div tts:backgroundImage="http://example.com/images/background.png"&gt;
+  &lt;p&gt;This division has a background image that appears under this paragraph.&lt;/p&gt;
+&lt;div&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-image-example-2"></a><table class="example"><caption>Example Fragment – Sharable Embedded Image Resource</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;head&gt;
+  &lt;resources&gt;
+    &lt;data xml:id="caption" type="image/png" length="119"&gt;
+      iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
+      YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
+    &lt;/data&gt;
+  &lt;/resources&gt;
+&lt;/head&gt;
+&lt;body&gt;
+  &lt;div&gt;
+    &lt;p&gt;
+      &lt;image&gt;
+        &lt;source src="#caption"/&gt;
+      &lt;/image&gt;
+    &lt;p&gt;
+    ...
+    &lt;p&gt;
+      &lt;image&gt;
+        &lt;source src="#caption"/&gt;
+      &lt;/image&gt;
+    &lt;p&gt;
+  &lt;/div&gt;
+&lt;/body&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-image-example-3"></a><table class="example"><caption>Example Fragment – External Image Resource with Non-Sharable Image Fallback</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;div&gt;
+  &lt;image&gt;
+    &lt;source src="http://example.com/images/caption.png" type="image/png"/&gt;
+    &lt;source&gt;
+      &lt;data type="image/png" length="119"&gt;
+        iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
+        YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
+      &lt;/data&gt;
+    &lt;/source&gt;
+  &lt;/image&gt;
+&lt;/div&gt;
+</pre></div>
+</td></tr></tbody></table><p></p></div><div class="div3">
+<h4><a id="embedded-content-vocabulary-resources"></a>9.1.6 resources</h4><p>The <code>resources</code> element is a container element used to group
+definitions of embedded content, including metadata that applies to this embedded content.</p><p>The <code>resources</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more elements in the
+<a href="#element-vocab-group-data"><code>Data.class</code></a>,
+<a href="#element-vocab-group-data"><code>Embedded.class</code></a>, or
+<a href="#element-vocab-group-data"><code>Font.class</code></a> element groups.</p><a id="elt-syntax-resources"></a><table class="syntax"><caption>XML Representation – Element Information Item: resources</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;resources
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, (<a href="#element-vocab-group-data">Data.class</a>|<a href="#element-vocab-group-embedded">Embedded.class</a>|<a href="#element-vocab-group-font">Font.class</a>)*
+&lt;/resources&gt;
+</pre></div>
+</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
+<code>resources</code> element, the implied time interval of this element is
+defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div><div class="div3">
+<h4><a id="embedded-content-vocabulary-source"></a>9.1.7 source</h4><p>The <code>source</code> element is used to specify the source of an <a href="#terms-embedded-content-resource">embedded content resource</a>.</p><p>The <code>source</code> element accepts as its children
+zero or more elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group followed by zero or one
+<a href="#embedded-content-vocabulary-data"><code>data</code></a> element.</p><p>If a <code>source</code> element specifies a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must not specify a
+child <a href="#embedded-content-vocabulary-data"><code>data</code></a> element, in which case it is referred to as
+an <a href="#terms-external-source">external source</a> if the <a href="#embedded-content-attribute-src"><code>src</code></a> attribute refers to an external resource, or
+a <a href="#terms-non-nested-embedded-source">non-nested embedded source</a>
+if the <a href="#embedded-content-attribute-src"><code>src</code></a> attribute refers to an embedded resource
+in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p><p>If a <code>source</code> element does not specify a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute, then it must specify a
+child <a href="#embedded-content-vocabulary-data"><code>data</code></a> element, in which case it is referred to as
+a <a href="#terms-nested-embedded-source">nested embedded source</a>.</p><p>A <code>source</code> element must not have an ancestor <code>source</code> element.</p><a id="elt-syntax-source"></a><table class="syntax"><caption>XML Representation – Element Information Item: source</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;source
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#embedded-content-attribute-format">format</a> = <a href="#embedded-content-value-data-format">&lt;data-format&gt;</a>
+  <a href="#embedded-content-attribute-src">src</a> = <a href="#embedded-content-value-data">&lt;data&gt;</a>
+  <a href="#embedded-content-attribute-type">type</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#embedded-content-vocabulary-data">data</a>?
+&lt;/source&gt;
+</pre></div>
+</td></tr></tbody></table><p>If a <a href="#embedded-content-attribute-format"><code>format</code></a> attribute is specified, then it provides additional hint information about the format (i.e., formal syntax) of the
+embedded content. Such information may be useful in cases where no standard media (content) type label has been defined. Depending on the
+context of use of a <code>source</code> element, the values of this attribute may be further constrained.</p><p>If a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute is specified and its value refers to a fragment of the <a href="#terms-enclosing-document-instance">enclosing document instance</a>,
+then there must be a <a href="#embedded-content-vocabulary-data"><code>data</code></a> element child of a <a href="#document-structure-vocabulary-resources"><code>resources</code></a>
+element which is identified by that fragment, i.e., has an <code>xml:id</code> attribute the value of which matches the fragment identifier.</p><p>If a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute is specified and its value does not refer to a fragment of the
+<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then
+a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute should be specified, in which case it must correspond with the media (content) type
+of the referenced resource.</p><p>If a <a href="#embedded-content-attribute-src"><code>src</code></a> attribute is specified and its value does refer to a fragment of the
+<a href="#terms-enclosing-document-instance">enclosing document instance</a>, then
+a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute must not be specified; rather, the content type of the embedded resource is determined by
+the value of the <a href="#embedded-content-attribute-type"><code>type</code></a> attribute on the referenced or embedded
+<a href="#embedded-content-vocabulary-data"><code>data</code></a> element.</p><p>The use of the <code>source</code> element is illustrated by the following examples.</p><a id="embedded-content-vocabulary-source-example-1"></a><table class="example"><caption>Example Fragment – External Source</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;image&gt;
+  &lt;source src="http://example.com/images/caption.png" type="image/png"/&gt;
+&lt;/image&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-source-example-2"></a><table class="example"><caption>Example Fragment – Non-Nested Embedded Source</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;data xml:id="caption" type="image/png" length="119"&gt;
+  iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
+  YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
+&lt;/data&gt;
+...
+&lt;image&gt;
+  &lt;source src="#caption"/&gt;
+&lt;/image&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p><a id="embedded-content-vocabulary-source-example-3"></a><table class="example"><caption>Example Fragment – Nested Embedded Source</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;image&gt;
+  &lt;source&gt;
+    &lt;data type="image/png" length="119"&gt;
+      iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
+      YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
+    &lt;/data&gt;
+  &lt;/source&gt;
+&lt;/image&gt;
+...
+</pre></div>
+</td></tr></tbody></table></div></div><div class="div2">
+<h3><a id="embedded-content-attribute-vocabulary"></a>9.2 Embedded Content Attribute Vocabulary</h3><p>This section defines the following attributes for use with certain <a href="#terms-embedded-content-element">embedded content elements</a>
+and <a href="#terms-embedded-data-element">data elements</a>:</p><ul><li><p><a href="#embedded-content-attribute-encoding"><b>9.2.1 encoding</b></a></p></li><li><p><a href="#embedded-content-attribute-format"><b>9.2.2 format</b></a></p></li><li><p><a href="#embedded-content-attribute-src"><b>9.2.3 src</b></a></p></li><li><p><a href="#embedded-content-attribute-type"><b>9.2.4 type</b></a></p></li></ul><div class="div3">
+<h4><a id="embedded-content-attribute-encoding"></a>9.2.1 encoding</h4><p>The <code>encoding</code> attribute is used to specify the encoding format of data.</p><p>The <code>encoding</code> attribute may be specified by an instance of the following
+element types:</p><ul><li><p><a href="#embedded-content-vocabulary-chunk"><code>chunk</code></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><code>data</code></a></p></li></ul><p>If specified, the value of an <code>encoding</code> attribute must take one of the following values as defined by
+<a href="#data-encodings">[Data Encodings]</a>:</p><ul><li><p><code>base16</code></p></li><li><p><code>base32</code></p></li><li><p><code>base32hex</code></p></li><li><p><code>base64</code></p></li><li><p><code>base64url</code></p></li></ul><p>If not specified, then <code>base64</code> semantics apply.</p></div><div class="div3">
+<h4><a id="embedded-content-attribute-format"></a>9.2.2 format</h4><p>The <code>format</code> attribute is used to specify hints about the media (content) format of
+an embedded content resource beyond media (content) type information
+provided by a <a href="#embedded-content-attribute-type"><code>type</code></a> attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <code>format</code> attribute is useful in the absence of a registered media (content) type,
+e.g., when no media (content) type is available or a generic type is used, such as
+<code>application/octet-stream</code>.</p></div><p>The <code>format</code> attribute may be specified by an instance of the following
+element types:</p><ul><li><p><a href="#embedded-content-vocabulary-audio"><code>audio</code></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><code>data</code></a></p></li><li><p><a href="#embedded-content-vocabulary-font"><code>font</code></a></p></li><li><p><a href="#embedded-content-vocabulary-image"><code>image</code></a></p></li><li><p><a href="#embedded-content-vocabulary-source"><code>source</code></a></p></li></ul><p>The value of a <code>format</code> attribute must adhere to a
+<a href="#embedded-content-value-data-format">&lt;data-format&gt;</a> expression.</p><p>Depending on the context of use, additional constraints may apply.</p></div><div class="div3">
+<h4><a id="embedded-content-attribute-src"></a>9.2.3 src</h4><p>The <code>src</code> attribute is used to specify the location or an identifier that maps to the location of data resource.</p><p>The <code>src</code> attribute may be specified by an instance of the following
+element types:</p><ul><li><p><a href="#embedded-content-vocabulary-audio"><code>audio</code></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><code>data</code></a></p></li><li><p><a href="#embedded-content-vocabulary-font"><code>font</code></a></p></li><li><p><a href="#embedded-content-vocabulary-image"><code>image</code></a></p></li><li><p><a href="#embedded-content-vocabulary-source"><code>source</code></a></p></li></ul><p>If specified, the value of a <code>src</code> attribute must adhere to the value syntax of the
+<code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>, §3.2.17.</p><p>Depending on the context of use, additional constraints may apply.</p></div><div class="div3">
+<h4><a id="embedded-content-attribute-type"></a>9.2.4 type</h4><p>The <code>type</code> attribute is used to specify the media (content) type of data resource, and may express additional
+parameters that characterize the data.</p><p>The <code>type</code> attribute may be specified by an instance of the following
+element types:</p><ul><li><p><a href="#embedded-content-vocabulary-audio"><code>audio</code></a></p></li><li><p><a href="#embedded-content-vocabulary-data"><code>data</code></a></p></li><li><p><a href="#embedded-content-vocabulary-font"><code>font</code></a></p></li><li><p><a href="#embedded-content-vocabulary-image"><code>image</code></a></p></li></ul><p>If specified, the value of a <code>type</code> attribute must adhere to the value syntax of the <code>Content-Type</code>
+MIME header defined by <a href="#mime">[MIME]</a>, §5.1.</p><p>If not specified, then the media (content) type is unknown or deliberately unspecified.</p><p>When decoding a data resource for which a <code>type</code> attribute is specified, then content processing
+must respect the specified type whether it is correct or not. That is, if a <code>type</code> attribute mis-specifies the
+type of a data resource, then content processing must not attempt to override that type by performing content
+sniffing.</p></div></div><div class="div2">
+<h3><a id="embedded-content-value-expressions"></a>9.3 Embedded Content Value Expressions</h3><p>Embedded content elements as well as certain style property values make use of the following expressions:</p><ul><li><p><a href="#embedded-content-value-audio"><b>9.3.1 &lt;audio&gt;</b></a></p></li><li><p><a href="#embedded-content-value-audio-format"><b>9.3.2 &lt;audio-format&gt;</b></a></p></li><li><p><a href="#embedded-content-value-data"><b>9.3.3 &lt;data&gt;</b></a></p></li><li><p><a href="#embedded-content-value-data-format"><b>9.3.4 &lt;data-format&gt;</b></a></p></li><li><p><a href="#embedded-content-value-font"><b>9.3.5 &lt;font&gt;</b></a></p></li><li><p><a href="#embedded-content-value-font-format"><b>9.3.6 &lt;font-format&gt;</b></a></p></li><li><p><a href="#embedded-content-value-image"><b>9.3.7 &lt;image&gt;</b></a></p></li><li><p><a href="#embedded-content-value-image-format"><b>9.3.8 &lt;image-format&gt;</b></a></p></li><li><p><a href="#embedded-content-value-unicode-range"><b>9.3.9 &lt;unicode-range&gt;</b></a></p></li></ul><p>In the syntax representations defined in this section, no
+linear whitespace (LWSP) is implied or permitted between tokens
+unless explicitly specified.</p><div class="div3">
+<h4><a id="embedded-content-value-audio"></a>9.3.1 &lt;audio&gt;</h4><p>An &lt;audio&gt; value expression is used to specify an <a href="#terms-audio-resource">audio resource</a> by reference.</p><a id="audio-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;audio&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;audio&gt;
+  : <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+</pre></div>
+</td></tr></tbody></table><p>If an &lt;audio&gt; value expression takes the form of a <a href="#terms-fragment-identifier">fragment identifier</a>,
+then that fragment identifier must reference an <a href="#embedded-content-vocabulary-audio"><code>audio</code></a> element that is a child of a
+<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p></div><div class="div3">
+<h4><a id="embedded-content-value-audio-format"></a>9.3.2 &lt;audio-format&gt;</h4><p>An &lt;audio-format&gt; expression is used to specify the format of a <a href="#terms-audio-resource">audio resource</a>. Additional format information is useful in the case
+of <a href="#terms-audio-resource">audio resources</a> that lack a registered media (content) type.</p><a id="audio-format-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;audio-format&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;audio-format&gt;
+  : <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
+  | <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+</pre></div>
+</td></tr></tbody></table><p>If a format expression takes the form of an <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
+then it must express an absolute URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not standardize the set of format tokens for use with audio content. Authors are encouraged to
+use tokens in common use, or absent that, to add a prefix <code>"x-"</code> to form a private use token.</p></div></div><div class="div3">
+<h4><a id="embedded-content-value-data"></a>9.3.3 &lt;data&gt;</h4><p>A &lt;data&gt; value expression is used to specify a data resource by reference.</p><a id="data-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;data&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;data&gt;
+  : <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+</pre></div>
+</td></tr></tbody></table><p>If a &lt;data&gt; value expression takes the form of a <a href="#terms-fragment-identifier">fragment identifier</a>,
+then that fragment identifier must reference an <a href="#embedded-content-vocabulary-data"><code>data</code></a> element that is a child of a
+<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p></div><div class="div3">
+<h4><a id="embedded-content-value-data-format"></a>9.3.4 &lt;data-format&gt;</h4><p>A &lt;data-format&gt; expression is used to specify the format of a data resource. Additional format information is useful in the case
+of data resources that lack a registered media (content) type.</p><a id="data-format-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;data-format&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;data-format&gt;
+  : <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
+  | <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+</pre></div>
+</td></tr></tbody></table><p>If a format expression takes the form of an <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
+then it must express an absolute URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not standardize the set of format tokens for use with data content. Authors are encouraged to
+use tokens in common use, or absent that, to add a prefix <code>"x-"</code> to form a private use token.</p></div></div><div class="div3">
+<h4><a id="embedded-content-value-font"></a>9.3.5 &lt;font&gt;</h4><p>An &lt;font&gt; expression is used to specify a <a href="#terms-font-resource">font resource</a> by reference.</p><a id="font-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;font&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;font&gt;
+  : <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+</pre></div>
+</td></tr></tbody></table><p>If a &lt;font&gt; expression takes the form of a <a href="#terms-fragment-identifier">fragment identifier</a>,
+then that fragment identifier must reference a <a href="#embedded-content-vocabulary-font"><code>font</code></a> element that is a child of a
+<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p></div><div class="div3">
+<h4><a id="embedded-content-value-font-format"></a>9.3.6 &lt;font-format&gt;</h4><p>A &lt;font-format&gt; expression is used to specify the format of a <a href="#terms-font-resource">font resource</a>. Additional format information is useful in the case
+of <a href="#terms-font-resource">font resources</a> due that lack a registered media (content) type.</p><a id="font-format-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;font-format&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;font-format&gt;
+  : eot                                     // embedded opentype
+  | otf                                     // opentype
+  | ttf                                     // truetype
+  | woff                                    // web open font format
+  | <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
+  | <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+</pre></div>
+</td></tr></tbody></table><p>If a format expression takes the form of an <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
+then it must express an absolute URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification standardizes a limited set of format tokens for use with font content. In case none of
+these tokens are appropriate, authors are encouraged to use tokens in common use, or absent that, to add a
+prefix <code>"x-"</code> to form a private use token.</p></div></div><div class="div3">
+<h4><a id="embedded-content-value-image"></a>9.3.7 &lt;image&gt;</h4><p>An &lt;image&gt; expression is used to specify an <a href="#terms-image-resource">image resource</a> by reference.</p><a id="image-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;image&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;image&gt;
+  : <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+</pre></div>
+</td></tr></tbody></table><p>If an &lt;image&gt; expression takes the form of a <a href="#terms-fragment-identifier">fragment identifier</a>,
+then that fragment identifier must reference an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element that is a child of a
+<a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element in the <a href="#terms-enclosing-document-instance">enclosing document instance</a>.</p></div><div class="div3">
+<h4><a id="embedded-content-value-image-format"></a>9.3.8 &lt;image-format&gt;</h4><p>An &lt;image-format&gt; expression is used to specify the format of a <a href="#terms-image-resource">image resource</a>. Additional format information is useful in the case
+of <a href="#terms-image-resource">image resources</a> that lack a registered media (content) type.</p><a id="image-format-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;image-format&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;image-format&gt;
+  : <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
+  | <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>
+</pre></div>
+</td></tr></tbody></table><p>If a format expression takes the form of a <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
+then it must express an absolute URI.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not standardize the set of format tokens for use with image content. Authors are encouraged to
+use tokens in common use, or absent that, to add a prefix <code>"x-"</code> to form a private use token.</p></div></div><div class="div3">
+<h4><a id="embedded-content-value-unicode-range"></a>9.3.9 &lt;unicode-range&gt;</h4><p>A &lt;unicode-range&gt; expression is used to specify a collection of Unicode codepoints by enumerating singleton codepoints or ranges of codepoints.</p><a id="unicode-range-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;unicode-range&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;unicode-range&gt;
+  : range ("," range)*
+
+range
+  : codepoint
+  | codepoint "-" codepoint
+
+codepoint
+  : ("U"|"u") "+" hexdigit-or-wildcard{1,6}
+
+hexdigit-or-wildcard
+  : <a href="#style-value-hexDigit">&lt;hexDigit&gt;</a>
+  | "?"
+</pre></div>
+</td></tr></tbody></table><p>No LWSP is permitted within a <code>codepoint</code> sub-expression.</p></div></div></div><div class="div1">
+<h2><a id="styling"></a>10 Styling</h2><p>This section specifies the <em>styling</em> matter of the core
+vocabulary catalog, where
+styling is to be understood as a separable layer of information that applies to
+content and that denotes authorial intentions about the presentation of
+that content.</p><p>Styling attributes are included in TTML to enable authorial intent of presentation
+to be included within a self-contained document. This section describes
+the semantics of style presentation in terms of a standard processing
+model. TTML Processors are not required to present <a href="#terms-document-instance">document instances</a> in any particular way; 
+but an implementation of this model by a TTML <a href="#terms-presentation-processor">presentation processor</a>
+that provides externally observable results that are consistent with this model is
+likely to lead to a user experience that closely resembles the experience intended by
+the documents' authors.</p><p>The semantics of TTML style presentation are described in terms of the model 
+in <a href="#xsl11">[XSL 1.1]</a>. The effects of the attributes in this section 
+are intended to be compatible with the layout and formatting model of XSL; however, Presentation agents
+may use any technology to satisfy the authorial intent of the document. In particular 
+since <a href="#css2">[CSS2]</a> is a subset of this model, a CSS processor may be used 
+for the features that the models have in common.</p><p>No normative use of an
+<code>&lt;?xml-stylesheet ... ?&gt;</code> processing instruction is defined
+by this specification.</p><div class="div2">
+<h3><a id="styling-element-vocabulary"></a>10.1 Styling Element Vocabulary</h3><p>The following elements specify the structure and principal styling aspects of a
+<a href="#terms-document-instance">document instance</a>:</p><ul><li><p><a href="#styling-vocabulary-initial"><b>10.1.1 initial</b></a></p></li><li><p><a href="#styling-vocabulary-style"><b>10.1.2 style</b></a></p></li><li><p><a href="#styling-vocabulary-styling"><b>10.1.3 styling</b></a></p></li></ul><div class="div3">
+<h4><a id="styling-vocabulary-initial"></a>10.1.1 initial</h4><p>The <code>initial</code> element is used to modify the initial value of one or more style properties, i.e, to specify use of different value(s) than
+the specification defined initial value(s).</p><p>The <code>initial</code> element accepts as its children zero or more <code>metadata</code> elements.</p><a id="elt-syntax-initial"></a><table class="syntax"><caption>XML Representation – Element Information Item: initial</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;initial
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
+&lt;/initial&gt;
+</pre></div>
+</td></tr></tbody></table><p>The <code>initial</code> element is illustrated by the following example, wherein
+the initial value of the <code>tts:color</code> property is defined to be <code>yellow</code>.</p><a id="style-vocabulary-initial-example-1"></a><table class="example"><caption>Example Fragment – <code>initial</code></caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;head&gt;
+  &lt;styling&gt;
+    <span class="strong">&lt;initial tts:color="yellow"/&gt;</span>
+  &lt;styling&gt;
+&lt;head&gt;
+...
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="styling-vocabulary-style"></a>10.1.2 style</h4><p>The <code>style</code> element is used to define
+a set of style specifications expressed as a
+specified style set in accordance with
+<a href="#semantics-style-resolution-processing-sss"><b>10.4.4.2 Specified Style Set Processing</b></a>.</p><p>The <code>style</code> element accepts as its children zero or more <code>metadata</code> elements.</p><a id="elt-syntax-style"></a><table class="syntax"><caption>XML Representation – Element Information Item: style</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;style
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
+&lt;/style&gt;
+</pre></div>
+</td></tr></tbody></table><p>If a <code>style</code> element appears as a descendant of a
+<code>region</code> element, then the <code>style</code> element must be
+ignored for the purpose of computing referential styles as defined by
+<a href="#semantics-style-association-referential"><b>10.4.1.2 Referential Styling</b></a> and <a href="#semantics-style-association-chained-referential"><b>10.4.1.3 Chained Referential Styling</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>That is to say, when referential styling is used by an element to
+refer to a <code>style</code> element, then the referenced <code>style</code>
+element must appear as a descendant of the <code>styling</code> element, and
+not in any other context.</p></div></div><div class="div3">
+<h4><a id="styling-vocabulary-styling"></a>10.1.3 styling</h4><p>The <code>styling</code> element is a container element used to group
+styling matter, including metadata that applies to styling matter.</p><p>The <code>styling</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more <code>initial</code> elements,
+followed by zero or more <code>style</code> elements.</p><a id="elt-syntax-styling"></a><table class="syntax"><caption>XML Representation – Element Information Item: styling</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;styling
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#styling-vocabulary-initial">initial</a>*, <a href="#styling-vocabulary-style">style</a>*
+&lt;/styling&gt;
+</pre></div>
+</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
+<code>styling</code> element, the implied time interval of this element is
+defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div></div><div class="div2">
+<h3><a id="styling-attribute-vocabulary"></a>10.2 Styling Attribute Vocabulary</h3><p>This section defines the <a href="#style-attribute-style"><b>10.2.1 style</b></a> attribute used
+with certain animation elements, <a href="#terms-content-element">content elements</a>, certain layout elements, and style definition elements.</p><p>In addition, this section specifies the following attributes in the TT Style Namespace
+for use with style definition elements, certain layout elements, and <a href="#terms-content-element">content elements</a>
+that support inline style specifications:</p><ul><li><p><a href="#style-attribute-backgroundColor"><b>10.2.2 tts:backgroundColor</b></a></p></li><li><p><a href="#style-attribute-backgroundImage"><b>10.2.3 tts:backgroundImage</b></a></p></li><li><p><a href="#style-attribute-backgroundPosition"><b>10.2.4 tts:backgroundPosition</b></a></p></li><li><p><a href="#style-attribute-backgroundRepeat"><b>10.2.5 tts:backgroundRepeat</b></a></p></li><li><p><a href="#style-attribute-border"><b>10.2.6 tts:border</b></a></p></li><li><p><a href="#style-attribute-color"><b>10.2.7 tts:color</b></a></p></li><li><p><a href="#style-attribute-direction"><b>10.2.8 tts:direction</b></a></p></li><li><p><a href="#style-attribute-display"><b>10.2.9 tts:display</b></a></p></li><li><p><a href="#style-attribute-displayAlign"><b>10.2.10 tts:displayAlign</b></a></p></li><li><p><a href="#style-attribute-extent"><b>10.2.11 tts:extent</b></a></p></li><li><p><a href="#style-attribute-fontFamily"><b>10.2.12 tts:fontFamily</b></a></p></li><li><p><a href="#style-attribute-fontKerning"><b>10.2.13 tts:fontKerning</b></a></p></li><li><p><a href="#style-attribute-fontShear"><b>10.2.15 tts:fontShear</b></a></p></li><li><p><a href="#style-attribute-fontSelectionStrategy"><b>10.2.14 tts:fontSelectionStrategy</b></a></p></li><li><p><a href="#style-attribute-fontSize"><b>10.2.16 tts:fontSize</b></a></p></li><li><p><a href="#style-attribute-fontStyle"><b>10.2.17 tts:fontStyle</b></a></p></li><li><p><a href="#style-attribute-fontVariantPosition"><b>10.2.18 tts:fontVariantPosition</b></a></p></li><li><p><a href="#style-attribute-fontWeight"><b>10.2.19 tts:fontWeight</b></a></p></li><li><p><a href="#style-attribute-height"><b>10.2.20 tts:height</b></a></p></li><li><p><a href="#style-attribute-letterSpacing"><b>10.2.21 tts:letterSpacing</b></a></p></li><li><p><a href="#style-attribute-lineHeight"><b>10.2.22 tts:lineHeight</b></a></p></li><li><p><a href="#style-attribute-opacity"><b>10.2.23 tts:opacity</b></a></p></li><li><p><a href="#style-attribute-origin"><b>10.2.24 tts:origin</b></a></p></li><li><p><a href="#style-attribute-overflow"><b>10.2.25 tts:overflow</b></a></p></li><li><p><a href="#style-attribute-padding"><b>10.2.26 tts:padding</b></a></p></li><li><p><a href="#style-attribute-position"><b>10.2.27 tts:position</b></a></p></li><li><p><a href="#style-attribute-ruby"><b>10.2.28 tts:ruby</b></a></p></li><li><p><a href="#style-attribute-rubyAlign"><b>10.2.29 tts:rubyAlign</b></a></p></li><li><p><a href="#style-attribute-rubyOffset"><b>10.2.30 tts:rubyOffset</b></a></p></li><li><p><a href="#style-attribute-rubyPosition"><b>10.2.31 tts:rubyPosition</b></a></p></li><li><p><a href="#style-attribute-showBackground"><b>10.2.32 tts:showBackground</b></a></p></li><li><p><a href="#style-attribute-textAlign"><b>10.2.33 tts:textAlign</b></a></p></li><li><p><a href="#style-attribute-textCombine"><b>10.2.34 tts:textCombine</b></a></p></li><li><p><a href="#style-attribute-textDecoration"><b>10.2.35 tts:textDecoration</b></a></p></li><li><p><a href="#style-attribute-textEmphasis"><b>10.2.36 tts:textEmphasis</b></a></p></li><li><p><a href="#style-attribute-textOrientation"><b>10.2.37 tts:textOrientation</b></a></p></li><li><p><a href="#style-attribute-textOutline"><b>10.2.38 tts:textOutline</b></a></p></li><li><p><a href="#style-attribute-textShadow"><b>10.2.39 tts:textShadow</b></a></p></li><li><p><a href="#style-attribute-unicodeBidi"><b>10.2.40 tts:unicodeBidi</b></a></p></li><li><p><a href="#style-attribute-visibility"><b>10.2.41 tts:visibility</b></a></p></li><li><p><a href="#style-attribute-width"><b>10.2.42 tts:width</b></a></p></li><li><p><a href="#style-attribute-wrapOption"><b>10.2.43 tts:wrapOption</b></a></p></li><li><p><a href="#style-attribute-writingMode"><b>10.2.44 tts:writingMode</b></a></p></li><li><p><a href="#style-attribute-zIndex"><b>10.2.45 tts:zIndex</b></a></p></li></ul><table border="1" class="ednote" summary="Editorial note: Additional Border Styling Attributes"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Additional Border Styling Attributes</b></td><td align="right" valign="top">2013-08-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Consider adding support for <code>tts:borderColor</code>, <code>tts:borderStyle</code>, and <code>tts:borderWidth</code>
+in order to provide a means to independently express styling of the four different borders (top, right, bottom, left). As currently specified, i.e., with only the
+<code>tts:border</code> attribute, one can only express the four borders using the same color, style, and width.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Background Clip, Origin, Size"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Background Clip, Origin, Size</b></td><td align="right" valign="top">2014-11-27</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Consider adding support for <code>tts:backgroundClip</code>,
+<code>tts:backgroundOrigin</code>, and
+<code>tts:backgroundSize</code>.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Additional Width/Height Related Attributes"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Additional Width/Height Related Attributes</b></td><td align="right" valign="top">2014-11-30</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Given the addition of <code>tts:width</code> and <code>tts:height</code>, consider also adding
+<code>tts:minWidth</code>, <code>tts:maxWidth</code>, <code>tts:minHeight</code>, and <code>tts:minHeight</code>.</td></tr></table><p>Unless explicitly permitted by an element type definition, an attribute in the TT Style Namespace should not be specified on an element
+unless it either applies to that element or denotes an inheritable style property. If it does not apply to that element
+and does not denote an inheritable style property, then it must be ignored for the purpose of non-validation processing.
+In the case of validation processing, such usage should be reported as a warning, or, if strict validation is performed,
+as an error.</p><p>Unless explicitly stated otherwise, linear white-space (LWSP) must
+appear between adjacent non-terminal components of a value of a TT
+Style property value unless some other delimiter is permitted and used.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification makes use of <em>lowerCamelCased</em> local
+names for style attributes that
+are based upon like-named properties defined by <a href="#xsl11">[XSL 1.1]</a>.
+This convention is likewise extended to token values of such
+properties.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>An inheritable style property may be expressed as a specified attribute on the
+root <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element or on a
+<a href="#terms-content-element">content element</a> type
+independently of whether the property applies to that
+element type. This capability permits the expression of an inheritable
+style property on ancestor elements to which the property
+does not apply.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Due to the general syntax of this specification (and the schemas it references) with respect
+to how style attributes are specified, particularly for the purpose of supporting inheritance,
+it is possible for an author to inadvertently specify a non-inheritable style attribute on
+an element that applies neither to that element or any of its descendants while still remaining
+conformant from a content validity perspective. Content authors may wish to make use of TTML
+content verification tools that detect and warn about such usage.</p></div><div class="div3">
+<h4><a id="style-attribute-style"></a>10.2.1 style</h4><p>The <code>style</code> attribute is used by referential style association
+to reference one or more <code>style</code> elements each of which define a style (property) set.</p><p>The <code>style</code> attribute may be specified by an instance of the following
+element types:</p><ul><li><p><a href="#animation-vocabulary-animate"><code>animate</code></a></p></li><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#animation-vocabulary-set"><code>set</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li><li><p><a href="#styling-vocabulary-style"><code>style</code></a></p></li></ul><p>If specified, the value of a <code>style</code> attribute must
+adhere to the <code>IDREFS</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§ 3.3.10, and, furthermore, each IDREF must reference a <code>style</code> element
+which has a <code>styling</code> element as an ancestor.</p><p>If the same IDREF, <em>ID<sub>1</sub></em>, appears more than one time in the value of a <code>style</code>
+attribute, then there should be an intervening IDREF, <em>ID<sub>2</sub></em>, where 
+<em>ID<sub>2</sub></em> is not equal to <em>ID<sub>1</sub></em>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This constraint is intended to discourage the use of redundant referential styling while still
+allowing the same style to be referenced multiple times in order to potentially override prior
+referenced styles, e.g., when an intervening, distinct style is referenced in the IDREFS list.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>See the specific element type definitions that permit use of the
+<code>style</code> attribute, as well as <a href="#semantics-style-association-referential"><b>10.4.1.2 Referential Styling</b></a> and <a href="#semantics-style-association-chained-referential"><b>10.4.1.3 Chained Referential Styling</b></a>, for
+further information on its semantics.</p></div></div><div class="div3">
+<h4><a id="style-attribute-backgroundColor"></a>10.2.2 tts:backgroundColor</h4><p>The <code>tts:backgroundColor</code> attribute is used to specify a style property that
+defines the background color of a region or an area generated by content flowed into a region.</p><div class="issue"><p class="prefix"><a id="issue-302"></a><b>Issue (issue-302):</b></p><p class="prefix"><b>Line Area Background Height</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/302">http://www.w3.org/AudioVideo/TT/tracker/issues/302</a></p><p>Fix definition of block progression dimension of background area of a line area. Neither XSL-FO nor CSS are sufficiently precise.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-backgroundColor"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-color">&lt;color&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>transparent</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>The <code>tts:backgroundColor</code> style is illustrated by the following example.</p><a id="style-attribute-backgroundColor-example-1"></a><table class="example"><caption>Example Fragment – Background Color</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="306px 114px"/&gt;
+  &lt;style <span class="strong">tts:backgroundColor="red"</span>/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:padding="3px 40px"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1" <span class="strong">tts:backgroundColor="purple"</span> tts:textAlign="center"&gt;
+  Twinkle, twinkle, little bat!&lt;br/&gt;
+  How &lt;span <span class="strong">tts:backgroundColor="green"</span>&gt;I wonder&lt;/span&gt; where you're at!
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-backgroundColor-example-1-images"></a><table class="example-images"><caption>Example Rendition – Background Color</caption><tbody><tr><td><img src="images/backgroundColor.png" alt="TTML backgroundColor style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+that defined by <a href="#xsl11">[XSL 1.1]</a>, § 7.8.2.</p></div></div><div class="div3">
+<h4><a id="style-attribute-backgroundImage"></a>10.2.3 tts:backgroundImage</h4><p>The <code>tts:backgroundImage</code> attribute is used to specify a style property that
+designates a background <a href="#non-content-image">non-content image</a> to be rendered as
+the background image of a region or an area generated by content flowed into a region.</p><p>A <code>tts:backgroundImage</code> attribute should not make reference to a <a href="#content-image">content image</a>
+used to represent actual content, such as a raster image rendering of a caption. Rather, the use of <code>tts:backgroundImage</code>
+should be limited to styling the background of an element where the content is represented by other means. If it is necessary
+to represent content using a raster image, then it should be expressed by means of an <a href="#embedded-content-vocabulary-image"><code>image</code></a>
+element in a block or inline context.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-backgroundImage"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#embedded-content-value-image">&lt;image&gt;</a> |
+none
+</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>An <a href="#embedded-content-value-image">&lt;image&gt;</a> expression used with this style property may directly reference an external <a href="#terms-image-resource">image resource</a>;
+however, authors should refrain from doing so, and instead, constrain their usage to only refer to <a href="#embedded-content-vocabulary-image"><code>image</code></a>
+children of a <a href="#embedded-content-vocabulary-resources"><code>resources</code></a> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Referring indirectly to an image by means of an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element makes it possible to
+specify an image as an <a href="#terms-embedded-data-resource">embedded data resource</a>, and specify
+additional information about the image, such as its content type, etc. Furthermore, by exploiting the use of multiple
+<a href="#embedded-content-vocabulary-source"><code>source</code></a> children in an <a href="#embedded-content-vocabulary-image"><code>image</code></a> element,
+it becomes possible to specify resolution specific images and fallback <a href="#terms-image-resource">image resources</a>.</p></div><p>The <code>tts:backgroundImage</code> style is illustrated by the following example.</p><a id="style-attribute-backgroundImage-example-1"></a><table class="example"><caption>Example Fragment – Background Image using Embedded Image Resource</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;head&gt;
+  &lt;resources&gt;
+    &lt;image xml:id="embeddedImage"&gt;
+      &lt;source&gt;
+        &lt;data type="image/png" length="119"&gt;
+          iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
+          YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
+        &lt;/data&gt;
+      &lt;/source&gt;
+    &lt;/image&gt;
+  &lt;/resources&gt;
+&lt;/head&gt;
+...
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="306px 114px"/&gt;
+  &lt;style tts:backgroundImage="red"/&gt;
+  &lt;style <span class="strong">tts:backgroundImage="#embeddedImage"</span>/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:padding="3px 40px"/&gt;
+&lt;/region&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Background Image Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Background Image Example Image</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of backgroundImage example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+that defined by <a href="#xsl11">[XSL 1.1]</a>, § 7.8.3.</p></div></div><div class="div3">
+<h4><a id="style-attribute-backgroundPosition"></a>10.2.4 tts:backgroundPosition</h4><p>The <code>tts:backgroundPosition</code> attribute is used to specify a style property that
+defines whether and how a background image is positioned in a region or an area generated by content flowed into a region.</p><p>This attribute may be specified by any element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-backgroundPosition"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-position">&lt;position&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>0% 0%</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>A percentage value component for a horizontal position offset is relative to the width of the
+positioning area minus the width of the background image.
+A percentage value component for a vertical position offset is relative to the height of the
+positioning area minus the height of the background image.
+The positioning area corresponds with the padding rectangle (padding box) of each area generated
+by applicable element.</p><p>The <code>tts:backgroundPosition</code> style is illustrated by the following example.</p><a id="style-attribute-backgroundPosition-example-1"></a><table class="example"><caption>Example Fragment – Background Position</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="306px 114px"/&gt;
+  &lt;style tts:backgroundImage="#embeddedImage"/&gt;
+  &lt;style <span class="strong">tts:backgroundPosition="center"</span>/&gt;
+&lt;/region&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Background Position Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Background Position Example Image</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of backgroundPosition example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+that defined by <a href="#css2">[CSS2]</a>, § 14.2.</p></div></div><div class="div3">
+<h4><a id="style-attribute-backgroundRepeat"></a>10.2.5 tts:backgroundRepeat</h4><p>The <code>tts:backgroundRepeat</code> attribute is used to specify a style property that
+defines whether and how a background image is repeated (tiled) into a region or an area generated by content flowed into a region.</p><p>This attribute may be specified by any element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-backgroundRepeat"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>repeat</code> |
+<code>repeatX</code> |
+<code>repeatY</code> |
+<code>noRepeat</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>repeat</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>The <code>tts:backgroundRepeat</code> style is illustrated by the following example.</p><a id="style-attribute-backgroundRepeat-example-1"></a><table class="example"><caption>Example Fragment – Background Repeat</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="306px 114px"/&gt;
+  &lt;style tts:backgroundImage="#embeddedImage"/&gt;
+  &lt;style <span class="strong">tts:backgroundRepeat="repeatX"</span>/&gt;
+&lt;/region&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Background Repeat Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Background Repeat Example Image</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of backgroundRepeat example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+that defined by <a href="#xsl11">[XSL 1.1]</a>, § 7.8.4.</p></div></div><div class="div3">
+<h4><a id="style-attribute-border"></a>10.2.6 tts:border</h4><p>The <code>tts:border</code> attribute is used to specify a style property that
+defines the border of a region or an area generated by content flowed into a region.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-border"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+[
+<a href="#style-value-borderWidth">&lt;borderWidth&gt;</a> ||
+<a href="#style-value-borderStyle">&lt;borderStyle&gt;</a> ||
+<a href="#style-value-borderColor">&lt;borderColor&gt;</a>
+]
+</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous (color and width only)</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If no border width is specified in the value of the <code>tts:border</code> property,
+then the border width must be interpreted as if a width of
+<code>medium</code> were specified.</p><p>If a computed value of the border width associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the one-dimensional Euclidean distance between
+the computed border width and the supported border width is minimized on a per-edge basis. If there are multiple closest supported values equally distant from
+the computed value for a given edge, then the value least distant from 0, i.e., the least border width, is used.</p></div><p>If no border style is specified in the value of the <code>tts:border</code> property,
+then the border style must be interpreted as if a style of
+<code>none</code> were specified.</p><p>If a computed value of the border style associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>solid</code>.</p><p>If no border color is specified in the value of the <code>tts:border</code> property,
+then the border color must be interpreted as if a color equal
+to the computed value of the element's <code>tts:color</code> style property were specified.</p><p>The <code>tts:border</code> style is illustrated by the following example.</p><a id="style-attribute-border-example-1"></a><table class="example"><caption>Example Fragment – Border</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="306px 114px"/&gt;
+  &lt;style <span class="strong">tts:border="2px solid red"</span>/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:padding="3px 40px"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1" <span class="strong">tts:border="4px solid green"</span> tts:textAlign="center"&gt;
+  Twinkle, twinkle, little bat!&lt;br/&gt;
+  How &lt;span <span class="strong">tts:border="8px solid blue"</span>&gt;I wonder&lt;/span&gt; where you're at!
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Border Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Border Example Image</b></td><td align="right" valign="top">2013-08-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of border example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+that defined by <a href="#xsl11">[XSL 1.1]</a>, § 7.31.3.</p></div></div><div class="div3">
+<h4><a id="style-attribute-color"></a>10.2.7 tts:color</h4><p>The <code>tts:color</code> attribute is used to specify a style property that
+defines the foreground color of marks associated with an area generated by content flowed into a region.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-color"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-color">&lt;color&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td>see prose</td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>The initial value of the <code>tts:color</code> property
+is considered to be implementation dependent. In the absence of
+end-user preference information, a conformant <a href="#terms-presentation-processor">presentation processor</a>
+should use an initial value that is highly contrastive to the
+background color of the <a href="#terms-root-container-region">root container region</a>.</p><p>The <code>tts:color</code> style is illustrated by the following example.</p><a id="style-attribute-color-example-1"></a><table class="example"><caption>Example Fragment – Color</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style <span class="strong">tts:color="white"</span>/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  In spring, when woods are &lt;span <span class="strong">tts:color="green"</span>&gt;getting green&lt;/span&gt;,&lt;br/&gt;
+  I'll try and tell you what I mean.
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-color-example-1-images"></a><table class="example-images"><caption>Example Rendition – Color</caption><tbody><tr><td><img src="images/color.png" alt="TTML color style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.18.1.</p></div></div><div class="div3">
+<h4><a id="style-attribute-direction"></a>10.2.8 tts:direction</h4><p>The <code>tts:direction</code> attribute is used to specify a style property that
+defines the directionality of an embedding or override according to
+the Unicode bidirectional algorithm.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-direction"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>ltr</code> |
+<code>rtl</code>
+</td></tr><tr><td><em>Initial:</em></td><td>
+<code>ltr</code>
+</td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>ltr</code>.</p><p>The <code>tts:direction</code> style is illustrated by the following example.</p><a id="style-attribute-direction-example-1"></a><table class="example"><caption>Example Fragment – Direction</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="265px 84px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  Little birds are playing&lt;br/&gt;
+  Bagpipes on the shore,&lt;br/&gt;
+  &lt;span tts:unicodeBidi="bidiOverride" <span class="strong">tts:direction="rtl"</span>&gt;where the tourists snore.&lt;/span&gt;
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-direction-example-1-images"></a><table class="example-images"><caption>Example Rendition – Direction</caption><tbody><tr><td>
+<img src="images/direction.png" alt="TTML direction style property">
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.29.1.</p></div></div><div class="div3">
+<h4><a id="style-attribute-display"></a>10.2.9 tts:display</h4><p>The <code>tts:display</code> attribute is used to specify a style property that
+defines whether an element is a candidate for layout and composition
+in a region.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-display"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>auto</code> |
+<code>none</code>
+</td></tr><tr><td><em>Initial:</em></td><td>
+<code>auto</code>
+</td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If the value of this attribute is <code>auto</code>,
+then the affected element is a candidate for region layout and
+presentation; however, if the value is <code>none</code>, then the
+affected element and its descendants must be considered ineligible for region
+layout and presentation.</p><p>The <code>tts:display</code> style is illustrated by the following example.</p><a id="style-attribute-display-example-1"></a><table class="example"><caption>Example Fragment – Display</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="369px 119px"
+            tts:backgroundColor="black"
+            tts:color="white"
+            tts:displayAlign="before"
+            tts:textAlign="start"/&gt;
+&lt;/region&gt;
+...
+&lt;div region="r1"&gt;
+  &lt;p dur="5s"&gt;
+    [[[
+    &lt;span <span class="strong">tts:display="none"</span>&gt;
+      &lt;set begin="1s" dur="1s" <span class="strong">tts:display="auto"</span>/&gt;
+      Beautiful soup,
+    &lt;/span&gt;
+    &lt;span <span class="strong">tts:display="none"</span>&gt;
+      &lt;set begin="2s" dur="1s" <span class="strong">tts:display="auto"</span>/&gt;
+      so rich and green,
+    &lt;/span&gt;
+    &lt;span <span class="strong">tts:display="none"</span>&gt;
+      &lt;set begin="3s" dur="1s" <span class="strong">tts:display="auto"</span>/&gt;
+      waiting in a hot tureen!
+    &lt;/span&gt;
+    ]]]
+  &lt;/p&gt;
+&lt;/div&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-display-example-1-images"></a><table class="example-images"><caption>Example Rendition – Display</caption><tbody><tr><td>
+<img src="images/display_0.png" alt="TTML display style property - [0,1)">
+</td></tr><tr><td>
+<img src="images/display_1.png" alt="TTML display style property - [1,2)">
+</td></tr><tr><td>
+<img src="images/display_2.png" alt="TTML display style property - [2,3)">
+</td></tr><tr><td>
+<img src="images/display_3.png" alt="TTML display style property - [3,4)">
+</td></tr><tr><td>
+<img src="images/display_4.png" alt="TTML display style property - [4,5)">
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#css2">[CSS2]</a>, § 9.2.4.</p></div></div><div class="div3">
+<h4><a id="style-attribute-displayAlign"></a>10.2.10 tts:displayAlign</h4><p>The <code>tts:displayAlign</code> attribute is used to specify a style property that
+defines the alignment of block areas in the block progression direction.</p><table border="1" class="ednote" summary="Editorial note: Justification in Block Progression Dimension"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Justification in Block Progression Dimension</b></td><td align="right" valign="top">2015-01-14</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add <code>justify</code> value to support justification in block progression dimension.</td></tr></table><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-displayAlign"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>before</code> |
+<code>center</code> |
+<code>after</code>
+</td></tr><tr><td><em>Initial:</em></td><td>
+<code>before</code>
+</td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#layout-vocabulary-region"><code>region</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>before</code>.</p><p>The <code>tts:displayAlign</code> style is illustrated by the following example.</p><a id="style-attribute-displayAlign-example-1"></a><table class="example"><caption>Example Fragment – Display Align</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="128px 66px" tts:origin="0px 0px"
+       tts:backgroundColor="black" tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:displayAlign="before"</span>/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:extent="192px 66px" tts:origin="128px 66px"/&gt;
+       tts:backgroundColor="green" tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:displayAlign="after"</span>/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r3"&gt;
+  &lt;style tts:extent="128px 66px"/&gt; style tts:origin="0px 132px"
+       tts:backgroundColor="black" tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:displayAlign="before"</span>/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r4"&gt;
+  &lt;style tts:extent="192px 66px" tts:origin="128px 198px"/&gt;
+       tts:backgroundColor="green" tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:displayAlign="after"</span>/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+...
+&lt;div&gt;
+  &lt;p region="r1"&gt;I sent a message to the fish:&lt;/p&gt;
+  &lt;p region="r2"&gt;I told them&lt;br/&gt; "This is what I wish."&lt;/p&gt;
+  &lt;p region="r3"&gt;The little fishes of the sea,&lt;/p&gt;
+  &lt;p region="r4"&gt;They sent an&lt;br/&gt; answer back to me.&lt;/p&gt;
+&lt;/div&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-displayAlign-example-1-images"></a><table class="example-images"><caption>Example Rendition – Display Align</caption><tbody><tr><td><img src="images/displayAlign.png" alt="TTML displayAlign style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.14.4.</p></div></div><div class="div3">
+<h4><a id="style-attribute-extent"></a>10.2.11 tts:extent</h4><p>The <code>tts:extent</code> attribute is used to specify the
+<em>width</em> and <em>height</em> of a region area. It may also be used to specify the extent of
+the <a href="#terms-root-container-region">root container region</a>, which has the effect of defining
+the <a href="#terms-document-coordinate-space">document coordinate space</a>.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-extent"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>auto</code> |
+<code>contain</code> |
+<code>cover</code> |
+<a href="#style-value-measure">&lt;measure&gt;</a> <a href="#style-value-measure">&lt;measure&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-tt"><code>tt</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>relative to width and height of <a href="#terms-root-container-region">root container region</a></td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute consists of two <a href="#style-value-measure">&lt;measure&gt;</a>
+specifications, then they must be interpreted as <em>width</em>
+and <em>height</em>, where the first specification is the
+<em>width</em>, and the second specification is the <em>height</em>.</p><p>The <a href="#style-value-measure">&lt;measure&gt;</a> value(s) used to express extent must be non-negative.</p><p>If the value of this attribute is <code>auto</code>, then the computed value
+of the style property must be considered to be the same as the extent of the <a href="#terms-root-container-region">root container region</a>.</p><table border="1" class="ednote" summary="Editorial note: Semantics of contain and cover"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Semantics of contain and cover</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define semantics of new <code>contain</code> and <code>cover</code> values.</td></tr></table><p>The extent of the <a href="#terms-root-container-region">root container region</a> is determined either by a
+<code>tts:extent</code> specified on the <code>tt</code> element, if
+present, or as described by <a href="#document-structure-vocabulary-tt"><b>8.1.1 tt</b></a> if not present.
+If <code>tts:extent</code> is specified on the <code>tt</code> element, then
+the width and height must be expressed in terms of two <a href="#style-value-length">&lt;length&gt;</a> specifications,
+and these specifications must be expressed as non-percentage, definite lengths using pixel units.</p><p>If a <code>tts:extent</code> attribute is specified on a <code>div</code> or <code>p</code> element, then that specification must be considered to be
+equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>div</code> or <code>p</code> element, where the
+extent of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
+value of this attribute.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
+the computed extent and the supported extent is minimized. If there are multiple closest supported values equally distant from
+the computed value, then the value most distant from [0,0], i.e., of greatest extent, is used.</p><p>This rule for resolving <em>closest supported value</em> makes use of the nearest larger rather than nearest smaller supported distance.
+The rationale for this difference in treatment is
+that use of a larger extent ensures that the affected content will be contained in the region area without causing region overflow,
+while use of a smaller extent makes region overflow more likely.</p></div><p>The <code>tts:extent</code> style is illustrated by the following example.</p><a id="style-attribute-extent-example-1"></a><table class="example"><caption>Example Fragment – Extent</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style <span class="strong">tts:extent="330px 122px"</span>/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  'Tis the voice of the Lobster:&lt;br/&gt;
+  I heard him declare,&lt;br/&gt;
+  "You have baked me too brown,&lt;br/&gt;
+  I must sugar my hair."
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-extent-example-1-images"></a><table class="example-images"><caption>Example Rendition – Extent</caption><tbody><tr><td><img src="images/extent.png" alt="TTML extent style property"></td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-attribute-fontFamily"></a>10.2.12 tts:fontFamily</h4><p>The <code>tts:fontFamily</code> attribute is used to specify a style property that
+defines the font family from which glyphs are selected for glyph areas generated
+by content flowed into a region.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontFamily"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+(<a href="#style-value-familyName">&lt;familyName&gt;</a> | <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a>)
+(<code>","</code>
+&nbsp;(<a href="#style-value-familyName">&lt;familyName&gt;</a> | <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a>))*
+</td></tr><tr><td><em>Initial:</em></td><td><code>default</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The initial value, <code>default</code>, is a generic font family name, and is
+further described in <a href="#style-value-genericFamilyName"><b>10.3.11 &lt;genericFamilyName&gt;</b></a> below.</p></div><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If a computed value of the property associated with this attribute is not supported, then a
+<a href="#terms-presentation-processor">presentation processor</a> must attempt to map the computed font family
+to a supported font family that has similar typographic
+characteristics, or, in the absence of such a mapping, it must
+use the value <code>default</code>.</p><p>The <code>tts:fontFamily</code> style is illustrated by the following example.</p><a id="style-attribute-fontFamily-example-1"></a><table class="example"><caption>Example Fragment – Font Family</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="474px 146px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+  &lt;style <span class="strong">tts:fontFamily="proportionalSansSerif"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;div region="r1"&gt;
+  &lt;p&gt;
+    "The time has come," the Walrus said,&lt;br/&gt;
+    "to talk of many things:
+  &lt;/p&gt;
+  &lt;p tts:textAlign="end" <span class="strong">tts:fontFamily="monospaceSerif"</span>&gt;
+    Of shoes, and ships, and sealing wax,&lt;br/&gt;
+    Of cabbages and kings,
+  &lt;/p&gt;
+  &lt;p&gt;
+    And why the sea is boiling hot,&lt;br/&gt;
+    and whether pigs have wings."
+  &lt;/p&gt;
+&lt;/div&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-fontFamily-example-1-images"></a><table class="example-images"><caption>Example Rendition – Font Family</caption><tbody><tr><td><img src="images/fontFamily.png" alt="TTML fontFamily style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.9.2.</p></div></div><div class="div3">
+<h4><a id="style-attribute-fontKerning"></a>10.2.13 tts:fontKerning</h4><p>The <code>tts:fontKerning</code> attribute is used to specify a style property that
+determines whether font kerning is applied when positioning glyph areas.</p><p>This attribute may be specified by any element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontKerning"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>none</code> |
+<code>normal</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If the value of this attribute is <code>normal</code>, then kerning should be applied if kerning data is available.
+If the value of this attribute is <code>none</code>, then kerning should not be applied whether or not kerning data is available.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><p>The <code>tts:fontKerning</code> style is illustrated by the following
+example.</p><table border="1" class="ednote" summary="Editorial note: Font Kerning Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Kerning Example</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:fontKerning.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#css3-fonts">[CSS Fonts]</a>,
+§ 6.3.</p></div></div><div class="div3">
+<h4><a id="style-attribute-fontSelectionStrategy"></a>10.2.14 tts:fontSelectionStrategy</h4><table border="1" class="ednote" summary="Editorial note: Define tts:fontSelectionStrategy"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Define tts:fontSelectionStrategy</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define <code>tts:fontSelectionStrategy</code> style property based on
+the XSL 1.1 <a href="http://www.w3.org/TR/xsl/#font-selection-strategy">font-selection-strategy</a> and
+recent <a href="http://lists.w3.org/Archives/Public/public-tt/2014Nov/0051.html">TTWG ML thread</a>.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Font Selection"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Selection</b></td><td align="right" valign="top">2014-11-21</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Specify font selection semantics, including how multiple author defined <a href="#terms-font-resource">font resources</a> combine
+with (local) platform defined <a href="#terms-font-resource">font resources</a> to obtain an ordered list of <a href="#terms-font-resource">font resources</a> for performing
+character to glyph mapping.</td></tr></table></div><div class="div3">
+<h4><a id="style-attribute-fontShear"></a>10.2.15 tts:fontShear</h4><p>The <code>tts:fontShear</code> attribute is used to specify a style property that
+determines whether and how a shear transformation is applied to glyph areas.</p><p>This attribute may be specified by any element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontShear"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-length">&lt;percentage&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>0%</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute is <code>0%</code>, then no shear transformation is applied; if the value is <code>100%</code>, then a 2D shear transformation
+of 90 degrees is applied in the axis associated with the inline progression direction; if the value is <code>-100%</code>, then a shear transformation
+of -90 degrees is applied. If the absolute value of the specified percentage is greater than 100%, then it must be interpreted as if 100% were specified with
+the appropriate sign.</p><p>If the inline progression direction corresponds to the X axis, then the 2D shear transformation is described by the following matrix:</p><div class="exampleInner"><pre>
+| 1 <em>a</em> 0 |
+| 0 1 0 |
+| 0 0 1 |
+</pre></div><p>where <em>a</em> is equal to the tangent of the shear angle.</p><p>If the inline progression direction corresponds to the Y axis, then the 2D shear transformation is described by the following matrix:</p><div class="exampleInner"><pre>
+| 1 0 0 |
+| <em>a</em> 1 0 |
+| 0 0 1 |
+</pre></div><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>The <code>tts:fontShear</code> style is illustrated by the following
+example.</p><table border="1" class="ednote" summary="Editorial note: Font Shear Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Shear Example</b></td><td align="right" valign="top">2015-01-07</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:fontShear.</td></tr></table></div><div class="div3">
+<h4><a id="style-attribute-fontSize"></a>10.2.16 tts:fontSize</h4><p>The <code>tts:fontSize</code> attribute is used to specify a style property
+that defines the font size for glyphs that are selected for glyph areas
+generated by content flowed into a region.</p><p>This attribute may be specified by any element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontSize"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a>?
+</td></tr><tr><td><em>Initial:</em></td><td><code>1c</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>if not <a href="#content-vocabulary-span"><code>region</code></a> element,
+then relative to parent element's font size; otherwise, relative to the
+<a href="#terms-computed-cell-size">computed cell size</a></td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If a single <a href="#style-value-length">&lt;length&gt;</a> value is specified, then this length applies
+equally to horizontal and vertical scaling of a glyph's EM square; if two
+<a href="#style-value-length">&lt;length&gt;</a> values are specified, then the first expresses the horizontal
+scaling and the second expresses vertical scaling.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Use of independent horizontal and vertical font sizes is expected to be used
+with cell based units in order to denote fonts that are two rows in height and
+one column in width.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>A glyph's EM square is conventionally defined as the EM square of the font that contains the glyph. That is,
+glyphs do not have an EM square that is distinct from their font's EM square.</p></div><p>If horizontal and vertical sizes are expressed independently, then the
+units of the <a href="#style-value-length">&lt;length&gt;</a> values must be the same.</p><p>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used to express font size must be non-negative.</p><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
+the computed font size and the supported font size is minimized. If there are multiple closest supported values equally distant from
+the computed value, then the value most distant from 0 (single length specification) or [0,0] (two length specifications) is used,
+i.e., the largest font size, is used.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The expression <code>1c</code> means one cell, where <code>'c'</code> expresses
+the <em>cell</em> length unit as defined by <a href="#style-value-length"><b>10.3.14 &lt;length&gt;</b></a>.
+When a single &lt;length&gt; is expressed using cell units, then it refers to the height of
+the <a href="#terms-computed-cell-size">computed cell size</a>.
+When two &lt;length&gt; values are expressed using cell units, then the first refers to the width of
+the <a href="#terms-computed-cell-size">computed cell size</a>, and the second refers to the height of the
+<a href="#terms-computed-cell-size">computed cell size</a>.</p></div><p>The <code>tts:fontSize</code> style is illustrated by the following example.</p><a id="style-attribute-fontSize-example-1"></a><table class="example"><caption>Example Fragment – Font Size</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="299px 97px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style <span class="strong">tts:fontSize="18px"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  Then fill up the glasses&lt;br/&gt;
+  with treacle and ink,&lt;br/&gt;
+  Or anything else&lt;br/&gt;
+  that is &lt;span <span class="strong">tts:fontSize="24px"</span>&gt;pleasant&lt;/span&gt; to drink.
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-fontSize-example-1-images"></a><table class="example-images"><caption>Example Rendition – Font Size</caption><tbody><tr><td><img src="images/fontSize.png" alt="TTML fontSize style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.9.4. The addition of a second length component to permit specifying font
+width and height independently is an extension introduced by TTML.</p></div></div><div class="div3">
+<h4><a id="style-attribute-fontStyle"></a>10.2.17 tts:fontStyle</h4><p>The <code>tts:fontStyle</code> attribute is used to specify a style property that
+defines the font style to apply to glyphs that are selected for glyph areas generated
+by content flowed into a region, where the mapping from font
+style value to specific font face or style parameterization is not determined
+by this specification.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontStyle"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>normal</code> |
+<code>italic</code> |
+<code>oblique</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>Use of the value <code>oblique</code>
+denotes a shear transformation (at an unspecified
+angle) in the inline progression dimension.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><p>The <code>tts:fontStyle</code> style is illustrated by the following example.</p><a id="style-attribute-fontStyle-example-1"></a><table class="example"><caption>Example Fragment – Font Style</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="331px 84px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  In autumn, when the leaves are brown,&lt;br/&gt;
+  Take pen and ink, and &lt;span <span class="strong">tts:fontStyle="italic"</span>&gt;write it down.&lt;/span&gt;
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-fontStyle-example-1-images"></a><table class="example-images"><caption>Example Rendition – Font Style</caption><tbody><tr><td><img src="images/fontStyle.png" alt="TTML fontStyle style property"></td></tr></tbody></table><p></p><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.9.7.</p></div></div><div class="div3">
+<h4><a id="style-attribute-fontVariantPosition"></a>10.2.18 tts:fontVariantPosition</h4><p>The <code>tts:fontVariantPosition</code> attribute is used to enable the selection
+of typographic subscript and superscript glyphs.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontVariantPosition"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>normal</code> |
+<code>sub</code> |
+<code>super</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><table border="1" class="ednote" summary="Editorial note: Font Position Variant Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Font Position Variant Example</b></td><td align="right" valign="top">2014-09-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add example source and rendering of tts:fontVariantPosition.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#css3-fonts">[CSS Fonts]</a>,
+§ 6.5.</p></div></div><div class="div3">
+<h4><a id="style-attribute-fontWeight"></a>10.2.19 tts:fontWeight</h4><p>The <code>tts:fontWeight</code> attribute is used to specify a style property
+that defines the font weight to apply to glyphs that are selected for glyph
+areas generated by content flowed into a region, where the mapping from font
+weight value to specific font face or weight parameterization is not determined
+by this specification.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-fontWeight"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>normal</code> |
+<code>bold</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><p>The <code>tts:fontWeight</code> style is illustrated by the following example.</p><a id="style-attribute-fontWeight-example-1"></a><table class="example"><caption>Example Fragment – Font Weight</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="376px 95px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  They told me you had been to her,&lt;br/&gt;
+  &lt;span <span class="strong">tts:fontWeight="bold"</span>&gt;and mentioned me to him:&lt;/span&gt;&lt;br/&gt;
+  She gave me a good character&lt;br/&gt;
+  &lt;span <span class="strong">tts:fontWeight="bold"</span>&gt;but said I could not swim.&lt;/span&gt;
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-fontWeight-example-1-images"></a><table class="example-images"><caption>Example Rendition – Font Weight</caption><tbody><tr><td><img src="images/fontWeight.png" alt="TTML fontWeight style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.9.9.</p></div></div><div class="div3">
+<h4><a id="style-attribute-height"></a>10.2.20 tts:height</h4><p>The <code>tts:height</code> attribute is used to specify the
+<em>height</em> of an area generated by content flowed into a region.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The term <em>height</em> is interpreted in a writing mode relative manner
+such that <em>height</em> always corresponds to a measure in the block
+progression direction. Therefore, in horizontal writing modes, <em>height</em> expresses a vertical measure,
+while, in vertical writing mode, <em>height</em> expresses a horizontal measure,
+where horizontal and vertical are always interpreted in an absolute sense.</p></div><p>If a <code>tts:height</code> attribute is specified on a <a href="#content-vocabulary-span"><code>span</code></a> element,
+then that <a href="#content-vocabulary-span"><code>span</code></a> element must be processed using
+<a href="#terms-inline-block-display">inline block display</a> semantics for the purpose of presentation processing.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-height"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-measure">&lt;measure&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>,
+<a href="#embedded-content-vocabulary-image"><code>image</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If a <a href="#style-value-measure">&lt;measure&gt;</a> is expressed as a <a href="#style-value-length">&lt;length&gt;</a> value, then it must be non-negative.</p><p>The <code>tts:height</code> style is illustrated by the following example.</p><table border="1" class="ednote" summary="Editorial note: Height Percentage"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Height Percentage</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Specify resolution of percentage value.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Height Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Height Example</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:height.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.15.6, and <a href="#css3-box">[CSS Box Model]</a>, § 9</p></div></div><div class="div3">
+<h4><a id="style-attribute-letterSpacing"></a>10.2.21 tts:letterSpacing</h4><p>The <code>tts:letterSpacing</code> attribute is used to specify a style property that
+increases or decreases the nominal distance between glyph areas.</p><p>Letter spacing has no affect at the beginning or ending of a line area, and must not
+be applied to zero-width glyphs. Furthermore, letter spacing must not cause normally connected glyphs,
+e.g., as used in cursive scripts or with cursive fonts, to become disconnected.</p><p>Letter spacing is applied independently from kerning and justification. Depending upon the font(s) in use,
+the script(s) being presented, and the capabilities of a presentation processor, either or both kerning and
+justification may be applied in addition to letter spacing.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-letterSpacing"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>normal</code> |
+<a href="#style-value-length">&lt;length&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>The value <code>normal</code> corresponds to specifying a <a href="#style-value-length">&lt;length&gt;</a> value of zero (0),
+i.e., neither expand nor compress adjacent glyph spacing.</p><p>If a <a href="#style-value-length">&lt;length&gt;</a> value is expressed as a positive scalar,
+then the spaces between adjacent glyphs are expanded by an additional amount equal to that scalar value.
+If expressed as a negative scalar,
+then the spaces between adjacent glyphs are compressed by an additional amount equal to that scalar value, possibly resulting
+in overlapping glyph areas, up to a maximum amount that results an effective advance of zero (0).</p><p>If a computed value of the letter spacing associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the one-dimensional Euclidean distance between
+the computed letter spacing and the supported letter spacing is minimized. If there are multiple closest supported values equally distant from
+the computed value for a given edge, then the value least distant from 0 is used.</p></div><p>The <code>tts:letterSpacing</code> style is illustrated by the following
+example.</p><table border="1" class="ednote" summary="Editorial note: Letter Spacing Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Letter Spacing Example</b></td><td align="right" valign="top">2014-11-30</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:letterSpacing.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#css3-text">[CSS Text]</a>,
+§ 8.2.</p></div></div><div class="div3">
+<h4><a id="style-attribute-lineHeight"></a>10.2.22 tts:lineHeight</h4><p>The <code>tts:lineHeight</code> attribute is used to specify a style property that
+defines the inter-baseline separation between line areas generated by content flowed into a region.</p><div class="issue"><p class="prefix"><a id="issue-284"></a><b>Issue (issue-284):</b></p><p class="prefix"><b>Normal Line Height Multiplier</b></p><p><b>Source</b>: <a href="https://www.w3.org/AudioVideo/TT/tracker/issues/284">https://www.w3.org/AudioVideo/TT/tracker/issues/284</a></p><p>Re-visit choice of 120% versus 125% for multiplier used in interpreting <code>normal</code> line height.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-lineHeight"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>normal</code> |
+<a href="#style-value-length">&lt;length&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>normal</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>relative to this element's font size</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute is <code>normal</code>, then the
+computed value of this style property is determined as follows:</p><ol class="enumar"><li><p>
+Let <em>P</em> be the <code>p</code> element to which this style property applies.
+</p></li><li><p>
+Let <em>FF</em> be the computed value of the <code>tts:fontFamily</code> style property that applies to <em>P</em>.
+</p></li><li><p>
+Let <em>FS</em> be the computed value of the <code>tts:fontSize</code> style property that applies to <em>P</em>.
+</p></li><li><p>
+Let <em>F0</em> be the first font obtained when sequentially mapping each font family in <em>FF</em> to a set of available fonts,
+where this set of available fonts is constrained as needed to satisfy the computed values of the <code>tts:fontStyle</code> and <code>tts:fontWeight</code>
+style properties that apply to <em>P</em>.
+</p></li><li><p>
+If <em>F0</em> is associated with font metrics that specify altitude <em>A</em>, descent <em>D</em>, and line gap <em>G</em>,
+then set <em>LH</em> to the sum of scaled(<em>A</em>), scaled(<em>D</em>), and scaled(<em>G</em>),
+where scaled(<em>X</em>) denotes font metric <em>X</em> scaled according to font size <em>FS</em>.
+</p></li><li><p>
+Otherwise, set <em>LH</em> to 125% of <em>FS</em>.
+</p></li><li><p>
+Set the computed value of this style property to <em>LH</em>.
+</p></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>If a content author wishes to avoid the possibility of different interpretations of <code>normal</code>, for example, due to differences in
+the set of available fonts, then it is recommended that a 
+<a href="#style-value-length">&lt;length&gt;</a> value expression be used to explicitly specify line height value.</p></div><p>If specified as a <a href="#style-value-length">&lt;length&gt;</a>, then the length must
+be non-negative.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
+the computed line height and the supported line height is minimized. If there are multiple closest supported values equally distant from
+the computed value, then the value most distant from 0, i.e., the largest line height, is used.</p></div><p>The <code>tts:lineHeight</code> style is illustrated by the following example.</p><a id="style-attribute-lineHeight-example-1"></a><table class="example"><caption>Example Fragment – Line Height</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="255px 190px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style tts:fontSize="16px"/&gt;
+  &lt;style <span class="strong">tts:lineHeight="32px"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  He thought he saw an elephant,&lt;br/&gt;
+  That practised on a fife:&lt;br/&gt;
+  He looked again, and found it was&lt;br/&gt;
+  A letter from his wife.&lt;br/&gt;
+  "At length I realise," he said,&lt;br/&gt;
+  "The bitterness of Life.
+"&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-lineHeight-example-1-images"></a><table class="example-images"><caption>Example Rendition – Line Height</caption><tbody><tr><td><img src="images/lineHeight.png" alt="TTML lineHeight style property"></td></tr></tbody></table><p></p><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.16.4. Furthermore, it is the intention of this specification that the
+allocation rectangle of a line be consistent with the <span class="strong">per-inline-height-rectangle</span>
+as defined by <a href="#xsl11">[XSL 1.1]</a>, § 4.5, i.e., that a CSS-style line box stacking strategy be used.
+</p></div></div><div class="div3">
+<h4><a id="style-attribute-opacity"></a>10.2.23 tts:opacity</h4><p>The <code>tts:opacity</code> attribute is used to specify a style property that
+defines the opacity (or conversely, the transparency)
+of marks associated with a region or an area generated by content flowed into a region.</p><p>When presented onto a visual medium, the opacity of the region is applied uniformly and on a linear scale
+to all marks produced by content targeted to the
+region after having applied applied any content element specific opacity to areas generated by that content.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-opacity"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-alpha">&lt;alpha&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td>
+<code>1.0</code>
+</td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>The <code>tts:opacity</code> style is illustrated by the following example.</p><table border="1" class="ednote" summary="Editorial note: Enhance Opacity Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Enhance Opacity Example</b></td><td align="right" valign="top">2013-08-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Enhance opacity example to demonstrate opacity on content elements.</td></tr></table><p></p><a id="style-attribute-opacity-example-1"></a><table class="example"><caption>Example Fragment – Opacity</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1" dur="5s"&gt;
+  &lt;set begin="0s" dur="1s" <span class="strong">tts:opacity="1.00"</span>/&gt;
+  &lt;set begin="1s" dur="1s" <span class="strong">tts:opacity="0.75"</span>/&gt;
+  &lt;set begin="2s" dur="1s" <span class="strong">tts:opacity="0.50"</span>/&gt;
+  &lt;set begin="3s" dur="1s" <span class="strong">tts:opacity="0.25"</span>/&gt;
+  &lt;set begin="4s" dur="1s" <span class="strong">tts:opacity="0.00"</span>/&gt;
+  &lt;style tts:extent="304px 77px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  The sun was shining on the sea
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-opacity-example-1-images"></a><table class="example-images"><caption>Example Rendition – Opacity</caption><tbody><tr><td>
+<img src="images/opacity_0.png" alt="TTML opacity style property - [0,1)">
+</td></tr><tr><td>
+<img src="images/opacity_1.png" alt="TTML opacity style property - [1,2)">
+</td></tr><tr><td>
+<img src="images/opacity_2.png" alt="TTML opacity style property - [2,3)">
+</td></tr><tr><td>
+<img src="images/opacity_3.png" alt="TTML opacity style property - [3,4)">
+</td></tr><tr><td>
+<img src="images/opacity_4.png" alt="TTML opacity style property - [4,5)">
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#css3-color">[CSS3 Color]</a>,
+§ 3.2.</p></div></div><div class="div3">
+<h4><a id="style-attribute-origin"></a>10.2.24 tts:origin</h4><p>The <code>tts:origin</code> attribute is used to specify the
+<em>x</em> and <em>y</em> coordinates of the origin of a
+region area with respect to the origin of the <a href="#terms-root-container-region">root container region</a>.</p><p>If both <code>tts:origin</code> and <a href="#style-attribute-position"><code>tts:position</code></a> attributes are
+specified on an element and <a href="#style-attribute-position"><code>tts:position</code></a> is a supported property,
+then the <code>tts:origin</code> attribute must be ignored for the purpose of presentation processing.</p><p>This attribute may be specified by any element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-origin"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>auto</code> |
+<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>relative to width and height of <a href="#terms-root-container-region">root container region</a></td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute consists of two <a href="#style-value-length">&lt;length&gt;</a> specifications,
+then they must be interpreted as <em>x</em> and <em>y</em> coordinates, where the first specification
+is the <em>x</em> coordinate, and the second specification is the <em>y</em> coordinate.</p><p>If the value of this attribute is <code>auto</code>, then the computed value
+of the style property must be considered to be the same as the origin of the <a href="#terms-root-container-region">root container region</a>.</p><p>If a <code>tts:origin</code> attribute is specified on a <code>div</code> or <code>p</code> element, then that specification must be considered to be
+equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>div</code> or <code>p</code> element, where the
+origin of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
+value of this attribute.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
+the computed origin and the supported origin is minimized. If there are multiple closest supported values equally distant from
+the computed value, then the value least distant from [0,0], i.e., closest to the coordinate space origin, is used.</p></div><p>The <code>tts:origin</code> style is illustrated by the following example.</p><a id="style-attribute-origin-example-1"></a><table class="example"><caption>Example Fragment – Origin</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style <span class="strong">tts:origin="40px 40px"</span>/&gt;
+  &lt;style tts:extent="308px 92px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  "To dine!" she shrieked in dragon-wrath.&lt;br/&gt;
+  "To swallow wines all foam and froth!&lt;br/&gt;
+   To simper at a table-cloth!"
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-origin-example-1-images"></a><table class="example-images"><caption>Example Rendition – Origin</caption><tbody><tr><td><img src="images/origin.png" alt="TTML origin style property"></td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-attribute-overflow"></a>10.2.25 tts:overflow</h4><p>The <code>tts:overflow</code> attribute is used to specify a style property that
+defines whether a region area is clipped or not if the descendant areas of the region overflow
+its extent.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-overflow"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>visible</code> |
+<code>hidden</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>hidden</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#layout-vocabulary-region"><code>region</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>If the value of this attribute is <code>visible</code>, then content should
+not be clipped outside of the affected region.
+If the value is <code>hidden</code>, then content should
+be clipped outside of the affected region.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Unless a manual line break element <code>br</code> is used by the content author,
+a paragraph of a given region will generate no more than one line area in that
+region if the computed values of the <code>tts:overflow</code> and <code>tts:wrapOption</code>
+style properties of the region are <code>visible</code> and <code>noWrap</code>,
+respectively.</p></div><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>hidden</code>.</p><p>The <code>tts:overflow</code> style is illustrated by the following example.</p><a id="style-attribute-overflow-example-1"></a><table class="example"><caption>Example Fragment – Overflow</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="232px 40px"/&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="red"/&gt;
+  &lt;style tts:displayAlign="before"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style tts:fontSize="18px"/&gt;
+  &lt;style tts:wrapOption="noWrap"/&gt;
+  &lt;style <span class="strong">tts:overflow="visible"</span>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:extent="232px 40px"/&gt;
+  &lt;style tts:origin="0px 43px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="red"/&gt;
+  &lt;style tts:displayAlign="before"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style tts:fontSize="18px"/&gt;
+  &lt;style tts:wrapOption="noWrap"/&gt;
+  &lt;style <span class="strong">tts:overflow="hidden"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  "But wait a bit," the Oysters cried,&lt;br/&gt;
+  "Before we have our chat;
+&lt;/p&gt;
+&lt;p region="r2"&gt;
+  For some of us are out of breath,&lt;br/&gt;
+  And all of us are fat!"
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-overflow-example-1-images"></a><table class="example-images"><caption>Example Rendition – Overflow</caption><tbody><tr><td><img src="images/overflow.png" alt="TTML overflow style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the <code>tts:noWrap</code> is set to
+<code>noWrap</code> to prevent automatic line wrapping (breaking);
+if this were not specified, then overflow would occur in the block
+progression direction as opposed to the inline progression direction.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.21.2.</p></div></div><div class="div3">
+<h4><a id="style-attribute-padding"></a>10.2.26 tts:padding</h4><p>The <code>tts:padding</code> attribute is used to specify padding (or inset)
+space on one or more sides of a region or an area generated by content flowed into a region.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-padding"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-length">&lt;length&gt;</a> |
+<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> |
+<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> |
+<a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>0px</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>relative to width and height of containing region</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If the value of this attribute consists of one <a href="#style-value-length">&lt;length&gt;</a> specification,
+then that length applies to all edges of the affected areas. If the value
+consists of two <a href="#style-value-length">&lt;length&gt;</a> specifications, then the first applies to the
+before and after edges, and the second applies to the start and end edges.
+If three <a href="#style-value-length">&lt;length&gt;</a> specifications are provided, then the first applies to the
+before edge, the second applies to the start and end edges, and the third applies
+to the after edge.
+If four <a href="#style-value-length">&lt;length&gt;</a> specifications are provided, then they apply to before, end,
+after, and start edges, respectively.</p><p>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used to express padding must be non-negative.</p><p>If padding is applied to a <a href="#content-vocabulary-span"><code>span</code></a> element, and content from that element
+is divided across multiple line areas, then the specified padding must be applied at each line break boundary. In contrast,
+within a single line area, if multiple inline areas are generated by the element, then the specified padding must be applied at
+the first and/or last generated inline area within a line area the inline progression order of the containing block level element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The behavior of padding on a <a href="#content-vocabulary-span"><code>span</code></a> element corresponds with the use of
+a CSS <code>box-decoration-break</code> property with the value <code>clone</code> at line breaks and the value <code>slice</code>
+at non-terminal, i.e., non-first and non-last, inline area boundaries, as defined by <a href="#css3-frag">[CSS Fragmentation]</a>, § 5.4.</p></div><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the one-dimensional Euclidean distance between
+the computed padding and the supported padding is minimized on a per-edge basis. If there are multiple closest supported values equally distant from
+the computed value for a given edge, then the value least distant from 0, i.e., the least padding, is used.</p></div><p>The <code>tts:padding</code> style is illustrated by the following example.</p><table border="1" class="ednote" summary="Editorial note: Enhance Padding Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Enhance Padding Example</b></td><td align="right" valign="top">2013-08-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Enhance padding example to demonstrate padding on content elements.</td></tr></table><p></p><a id="style-attribute-padding-example-1"></a><table class="example"><caption>Example Fragment – Padding</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="446px 104px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+  &lt;style <span class="strong">tts:padding="10px 40px"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1" tts:backgroundColor="red"&gt;
+  Just the place for a Snark! I have said it twice:&lt;br/&gt;
+  That alone should encourage the crew.&lt;br/&gt;
+  Just the place for a Snark! I have said it thrice:&lt;br/&gt;
+  What I tell you three times is true.
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p>When rendering an area to which padding applies, the background color that
+applies to the area is rendered into the padded portion of the area.</p><a id="style-attribute-padding-example-1-images"></a><table class="example-images"><caption>Example Rendition – Padding</caption><tbody><tr><td>
+<img src="images/padding.png" alt="TTML padding style property">
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.31.15, except that individual shorthand values map to writing
+mode relative padding values as defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.8.31, 7.8.32, 7.8.33, and 7.8.34.</p></div></div><div class="div3">
+<h4><a id="style-attribute-position"></a>10.2.27 tts:position</h4><p>The <code>tts:position</code> attribute is used as an alternative way to specify the position
+of a region area with respect the <a href="#terms-root-container-region">root container region</a>.</p><p>If both <code>tts:position</code> and <a href="#style-attribute-origin"><code>tts:origin</code></a> attributes are
+specified on an element and <code>tts:position</code> is a supported property,
+then the <code>tts:origin</code> attribute must be ignored for the purpose of presentation processing.</p><p>This attribute may be specified by any element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-position"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-position">&lt;position&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>center</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-tt"><code>tt</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>A percentage value component for a horizontal position offset is relative to the width of the
+positioning area minus the width of the associated region.
+A percentage value component for a vertical position offset is relative to the height of the
+positioning area minus the height of the associated region.</p><p>The following image depicts a position value "75% 50%", where the rectangle with dashed line denotes the positioning area and the rectangle
+with solid line denotes the region being positioned. In this case the region is positioned such that a vertical line located at 75% of its width coincides with
+a vertical line located at 75% of the width of the positioning area, and a horizontal line located at 50% of its height coincides with
+a vertical line located at 50% of the width of the posititoning area.</p><a id="style-attribute-position-percentage-based-positioning"></a><table class="example-images"><caption>Percentage Based Positioning</caption><tbody><tr><td>
+<img src="images/position_0.png" alt="TTML position style property using percentages">
+</td></tr></tbody></table><p>If specified on a <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element, then, if a
+<a href="#terms-related-media-object">related media object</a> exists, the positioning area corresponds with
+the <a href="#terms-related-media-object-region">related media object region</a>, or, if no
+<a href="#terms-related-media-object">related media object</a> exists, the positioning area corresponds with
+an unspecified presentation region determined by the <a href="#terms-document-processing-context">document processing context</a>.
+For other applicable element types, the positioning area corresponds with the content rectangle (content box)
+of the <a href="#terms-root-container-region">root container region</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The <a href="#terms-root-container-region">root container region</a> has no border or padding; consequently, its border, padding, and
+content rectangles (boxes) are coterminous.</p></div><p>If a horizontal or vertical position offset is specified by a <code>tts:position</code> attribute in the form of a scalar value
+on a <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element, then that value must be expressed using pixel (<code>px</code>) units,
+in which case a pixel must be interpreted as a pixel in the <a href="#terms-presentation-context-coordinate-space">presentation context coordinate space</a>
+(and not a pixel in the <a href="#terms-document-coordinate-space">document coordinate space</a>).</p><p>If a <code>tts:position</code> attribute is specified on a <a href="#content-vocabulary-div"><code>div</code></a> or
+<a href="#content-vocabulary-p"><code>p</code></a> element, then that specification must be considered to be
+equivalent to specifying an anonymous <a href="#terms-inline-region">inline region</a> child of the <code>div</code> or <code>p</code> element, where the
+position of the corresponding region, also referred to as an <a href="#terms-implied-inline-region">implied inline region</a>, is equal to the
+value of this attribute.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
+the computed position and the supported position is minimized. If there are multiple closest supported values equally distant from
+the computed value, then the value least distant from [0,0], i.e., closest to the coordinate space position, is used.</p></div><p>The <code>tts:position</code> style is illustrated by the following example, which positions a region so that it is
+centered in the horizontal dimension and has a bottom edge 10% above the bottom of the positioning area in the vertical dimension.</p><a id="style-attribute-position-example-1"></a><table class="example"><caption>Example Fragment – Position</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style <span class="strong">tts:position="center bottom 10%"</span>/&gt;
+  &lt;style tts:extent="308px 92px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="center"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  "To dine!" she shrieked in dragon-wrath.&lt;br/&gt;
+  "To swallow wines all foam and froth!&lt;br/&gt;
+   To simper at a table-cloth!"
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Position Example Image"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Position Example Image</b></td><td align="right" valign="top">2014-11-28</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert image of position example.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+the <code>background-position</code> property defined by <a href="#css3-bb">[CSS Backgrounds and Borders]</a>, § 3.6.</p></div></div><div class="div3">
+<h4><a id="style-attribute-ruby"></a>10.2.28 tts:ruby</h4><p>The <code>tts:ruby</code> attribute is used to specify the application of ruby
+styling.</p><p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
+this attribute applies as a style property only to those element types indicated in the following table.</p><a id="style-property-details-ruby"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>none</code> |
+<code>container</code> |
+<code>base</code> |
+<code>baseContainer</code> |
+<code>text</code> |
+<code>textContainer</code> |
+<code>delimiter</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p></p><p>If the value of this attribute is <code>none</code>, then no ruby semantics apply; otherwise, the ruby semantics enumerated by
+<a href="#ruby-semantics-mapping-table"><b>Table 8-1 – Ruby Semantics Mapping</b></a> apply.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>none</code>.</p><a id="ruby-semantics-mapping-table"></a><table class="common"><caption>Table 8-1 – Ruby Semantics Mapping</caption><col width="25%" span="1"><col width="25%" span="1"><col width="25%" span="1"><col width="25%" span="1"><col span="1"><tbody><tr><th>Category</th><th>tts:ruby</th><th>Annotation <a href="#ruby">[Ruby]</a></th><th>CSS display <a href="#cssruby">[CSS Ruby]</a></th></tr><tr><td>Ruby Container</td><td><code>container</code></td><td><code>ruby</code></td><td><code>ruby</code></td></tr><tr><td>Ruby Base Content</td><td><code>base</code></td><td><code>rb</code></td><td><code>ruby-base</code></td></tr><tr><td>Ruby Text Content</td><td><code>text</code></td><td><code>rt</code></td><td><code>ruby-text</code></td></tr><tr><td>Ruby Base Container</td><td><code>baseContainer</code></td><td><code>rbc</code></td><td><code>ruby-base-container</code></td></tr><tr><td>Ruby Text Container</td><td><code>textContainer</code></td><td><code>rtc</code></td><td><code>ruby-text-container</code></td></tr><tr><td>Ruby Fallback Delimiter</td><td><code>delimiter</code></td><td><code>rp</code></td><td><code>none</code> | <code>inline</code></td></tr></tbody></table><p>When using <code>tts:ruby</code>, the following nesting constraints apply:</p><ul><li><p>if the computed value of <code>tts:ruby</code> is <code>container</code>, then the
+computed value of <code>tts:ruby</code> of all ancestor elements is <code>none</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>container</code>, then the
+computed value of <code>tts:ruby</code> of its first child element is <code>baseContainer</code>
+or <code>base</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>baseContainer</code>, then the
+computed value of <code>tts:ruby</code> of its parent element is <code>container</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>baseContainer</code>, then the
+computed value of <code>tts:ruby</code> of its first child element is <code>base</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>baseContainer</code>, then its
+preceding sibling is <code>null</code> (i.e., no preceding sibling);</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>textContainer</code>, then the
+computed value of <code>tts:ruby</code> of its parent element is <code>container</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>textContainer</code>, then the
+computed value of <code>tts:ruby</code> of its first child element is either <code>text</code> or <code>delimiter</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>textContainer</code>, then the
+computed value of <code>tts:ruby</code> of its preceding sibling is <code>baseContainer</code> or
+<code>textContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>textContainer</code>, then the
+computed value of <code>tts:ruby</code> of no more than one sibling is <code>textContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>base</code>, then the
+computed value of <code>tts:ruby</code> of its parent element is either <code>container</code> or
+<code>baseContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>base</code>, then its
+preceding sibling is either <code>null</code> (i.e., no preceding sibling) or the
+computed value of <code>tts:ruby</code> of its preceding sibling is <code>base</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>base</code> and the
+computed value of <code>tts:ruby</code> of its parent element is <code>container</code>,
+then the computed value of <code>tts:ruby</code> of no sibling is <code>base</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>base</code>, then the
+computed value of <code>tts:ruby</code> of no descendant element is not <code>none</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>text</code>, then the
+computed value of <code>tts:ruby</code> of its parent element is either <code>container</code> or
+<code>textContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>text</code>, then the
+computed value of <code>tts:ruby</code> of its preceding sibling is <code>base</code>,
+<code>text</code>, or <code>delimiter</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>text</code> and the
+computed value of <code>tts:ruby</code> of its parent element is <code>container</code>,
+then the computed value of <code>tts:ruby</code> of no sibling is <code>text</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>text</code>, then the
+computed value of <code>tts:ruby</code> of no descendant element is not <code>none</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>delimiter</code>, then the
+computed value of <code>tts:ruby</code> of its parent element is either <code>container</code> or <code>textContainer</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>delimiter</code>, then the
+computed value of <code>tts:ruby</code> of its preceding sibling is <code>base</code> or
+<code>text</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>delimiter</code>, then the
+computed value of <code>tts:ruby</code> of exactly one sibling is <code>delimiter</code>;</p></li><li><p>if the computed value of <code>tts:ruby</code> is <code>delimiter</code>, then the
+computed value of <code>tts:ruby</code> of no descendant element is not <code>none</code>;</p></li></ul><p>A validating processor must treat a violation of any of the above constraints as an error.
+For the purpose of presentation processing, the violation of any of these constraints should result in fallback (inline)
+presentation of ruby text annotations.</p><p>When performing normal presentation processing of ruby text annotations, delimiter content must not generate any
+inline areas. When performing fallback presentation of ruby, both delimiter and non-delimiter ruby (base and text) content
+must generate normal inline areas.</p><p>If a presentation processor does not support ruby presentation, then it must perform fallback ruby presentaton.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The above listed constraints are intended to be interpreted as specifying the following nesting model:</p><div class="exampleInner"><pre>
+container
+  : base text
+  | base delimiter text delimiter
+  | baseContainer textContainer textContainer?
+
+baseContainer
+  : base+
+
+textContainer
+  : text+
+  | delimiter text+ delimiter
+
+base | text | delimiter
+  : ( #PCDATA | { span - tts:ruby } )*
+</pre></div><p>This model corresponds to the maximal content model for the <code>ruby</code> element defined by <a href="#ruby">[Ruby]</a>, §2.1,
+with the exception that <code>rtc</code> is effectively extended to permit the optional use of delimiters (<code>rp</code>):</p><div class="exampleInner"><pre>
+ruby
+  : rb rt
+  | rb rp rt rp
+  | rbc rtc rtc?
+
+rbc
+  : rb+
+
+rtc
+  : rt+
+  | rp rt+ rp                            // extension to <a href="#ruby">[Ruby]</a>
+</pre></div></div><div class="note"><p class="prefix"><b>Note:</b></p><p>While not supporting as many opportunities for markup minimization as allowed by <a href="#html5">[HTML5]</a>,
+the formulation of ruby annotation defined here does allow the following shorthands:</p><div class="exampleInner"><pre>
+base text =
+  baseContainer
+    base
+  textContainer
+    text
+
+base delimiter text delimiter =
+  baseContainer
+    base
+  textContainer
+    delimiter text delimiter
+</pre></div><p>Given the content of <code>base</code> is <code>B</code> and the content of
+<code>text</code> is <code>T</code>, then the expression <code>base text</code> could be represented variously in <a href="#html5">[HTML5]</a> as follows:</p><div class="exampleInner"><pre>
+&lt;ruby&gt;B&lt;rt&gt;T&lt;/ruby&gt;
+&lt;ruby&gt;B&lt;rt&gt;T&lt;/rt&gt;&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;rt&gt;T&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rt&gt;T&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/ruby&gt;
+&lt;ruby&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/ruby&gt;
+&lt;ruby&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/rtc&gt;&lt;/ruby&gt;
+&lt;ruby&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/ruby&gt;
+&lt;ruby&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/rtc&gt;&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;rtc&gt;&lt;rt&gt;T&lt;/rtc&gt;&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rtc&gt;&lt;rt&gt;T&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rtc&gt;&lt;rt&gt;T&lt;/rtc&gt;&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rtc&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/ruby&gt;
+&lt;ruby&gt;&lt;rb&gt;B&lt;/rb&gt;&lt;rtc&gt;&lt;rt&gt;T&lt;/rt&gt;&lt;/rtc&gt;&lt;/ruby&gt;
+</pre></div><p>Whereas, in TTML2, the following alternative expressions are possible:</p><div class="exampleInner"><pre>
+&lt;span tts:ruby="container"&gt;
+  &lt;span tts:ruby="base"&gt;B&lt;/span&gt;
+  &lt;span tts:ruby="text"&gt;T&lt;/span&gt;
+&lt;/span&gt;
+</pre></div><p>or its equivalent</p><div class="exampleInner"><pre>
+&lt;span tts:ruby="container"&gt;
+  &lt;span tts:ruby="baseContainer"&gt;
+    &lt;span tts:ruby="base"&gt;B&lt;/span&gt;
+  &lt;/span&gt;
+  &lt;span tts:ruby="textContainer"&gt;
+    &lt;span tts:ruby="text"&gt;T&lt;/span&gt;
+  &lt;/span&gt;
+&lt;/span&gt;
+</pre></div></div><p>Use of <code>tts:ruby</code> to specify simple ruby annotation is illustrated by the following example.</p><a id="style-attribute-ruby-example-1"></a><table class="example"><caption>Example Fragment – Simple Ruby</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;span <span class="strong">tts:ruby="container"</span>&gt;
+  &lt;span <span class="strong">tts:ruby="base"</span>&gt;利用許諾&lt;/span&gt;
+  &lt;span <span class="strong">tts:ruby="text"</span>&gt;ライセンス&lt;/span&gt;
+&lt;/span&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-ruby-example-1-images"></a><table class="example-images"><caption>Example Rendition – Simple Ruby</caption><tbody><tr><td><img src="images/ruby_1.png" alt="TTML ruby style property"></td></tr></tbody></table><p>Use of <code>tts:ruby</code> to specify complex ruby annotation is illustrated by the following example.</p><a id="style-attribute-ruby-example-2"></a><table class="example"><caption>Example Fragment – Complex Ruby</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;span&gt;
+  &lt;span <span class="strong">tts:ruby="container"</span>&gt;
+    &lt;span <span class="strong">tts:ruby="baseContainer"</span>&gt;
+      &lt;span <span class="strong">tts:ruby="base"</span>&gt;東南&lt;/span&gt;
+    &lt;/span&gt;
+    &lt;span <span class="strong">tts:ruby="textContainer"</span> tts:rubyPosition="before"&gt;
+      &lt;span <span class="strong">tts:ruby="text"</span>&gt;とうなん&lt;/span&gt;
+    &lt;/span&gt;
+    &lt;span <span class="strong">tts:ruby="textContainer"</span> tts:rubyPosition="after"&gt;
+      &lt;span <span class="strong">tts:ruby="text"</span>&gt;たつみ&lt;/span&gt;
+    &lt;/span&gt;
+  &lt;/span&gt;
+  &lt;span&gt;の方角&lt;/span&gt;
+&lt;/span&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-ruby-example-2-images"></a><table class="example-images"><caption>Example Rendition – Complex Ruby</caption><tbody><tr><td><img src="images/ruby_2.png" alt="TTML ruby style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#ruby">[Ruby]</a> and <a href="#cssruby">[CSS Ruby]</a>. See also
+<a href="#jlreq">[JLREQ]</a>, §3.3, for further information.</p></div></div><div class="div3">
+<h4><a id="style-attribute-rubyAlign"></a>10.2.29 tts:rubyAlign</h4><p>The <code>tts:rubyAlign</code> attribute is used to specify the position of ruby text within the inline area generated by the ruby text container annotation.</p><p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
+this attribute applies as a style property only to those element types indicated in the following table.</p><a id="style-property-details-rubyAlign"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>start</code> |
+<code>center</code> |
+<code>spaceBetween</code> |
+<code>spaceAround</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>spaceAround</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a> only if the computed value of <a href="#style-attribute-ruby">tts:ruby</a> is <code>container</code>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p></p><p>If the value of this attribute is <code>start</code>, then the start edge of the first glyph area descendant of an inline area generated from a ruby text container
+or ruby text annotation is aligned to the start edge of that inline area.
+If the value is <code>center</code>, then excess whitespace
+is equally distributed before and after the first and last glyphs, respectively.
+If the value is <code>spaceBetween</code>, then excess whitespace
+is equally distributed between each glyph area descendant.
+If the value is <code>spaceAround</code>, then excess whitespace
+is equally distributed before and after each glyph area descendant.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>spaceAround</code>.</p><table border="1" class="ednote" summary="Editorial note: Ruby Align Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Ruby Align Example</b></td><td align="right" valign="top">2014-09-20</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add example source and rendering of tts:rubyAlign.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#cssruby">[CSS Ruby]</a>, §4.3, and the examples and example
+renderings shown there apply.</p></div></div><div class="div3">
+<h4><a id="style-attribute-rubyOffset"></a>10.2.30 tts:rubyOffset</h4><p>The <code>tts:rubyOffset</code> attribute is used to specify the offset (distance) of ruby text with respect to its associated ruby base
+in the block progression dimension.</p><p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
+this attribute applies as a style property only to those element types indicated in the following table.</p><a id="style-property-details-rubyOffset"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-length">&lt;length&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>0px</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a> only if the computed value of <a href="#style-attribute-ruby">tts:ruby</a> is <code>container</code>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>relative to this element's font size</td></tr><tr><td><em>Animatable:</em></td><td>continuous</td></tr></tbody></table><p></p><p>If specified, the value of <code>tts:rubyOffset</code> expresses the offset (distance) between padding edge <em>E<sub>1</sub></em> of the inline area
+generated by a ruby text container (explicit or implied) and padding edge <em>E<sub>2</sub></em>  of the inline area generated by a ruby base container (explicit or implied), where
+<em>E<sub>1</sub></em> and <em>E<sub>2</sub></em> are perpendicular to the block progression direction and are (or would be) adjacent in the absence of
+such an offset.</p><p>Negative length expressions are permitted.</p><table border="1" class="ednote" summary="Editorial note: Ruby Offset Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Ruby Offset Example</b></td><td align="right" valign="top">2014-10-02</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add example source and rendering of tts:rubyOffset.</td></tr></table></div><div class="div3">
+<h4><a id="style-attribute-rubyPosition"></a>10.2.31 tts:rubyPosition</h4><p>The <code>tts:rubyPosition</code> attribute is used to specify the position of ruby text in the block progression dimension
+with respect to its associated ruby base.</p><table border="1" class="ednote" summary="Editorial note: Outside Annotations"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Outside Annotations</b></td><td align="right" valign="top">2015-01-14</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add <code>auto</code> and <code>outside</code> values as defined by &lt;emphasisPosition&gt; expressions.</td></tr></table><p>This attribute may be specified by any element type that permits use of attributes in the TT Style Namespace; however,
+this attribute applies as a style property only to those element types indicated in the following table.</p><a id="style-property-details-rubyPosition"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>before</code> |
+<code>after</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>before</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a> only if the computed value of <a href="#style-attribute-ruby">tts:ruby</a> is <code>container</code>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p></p><p>If the value of this attribute is <code>before</code>, then an inline area generated from a ruby text container or ruby text annotation
+is placed before (prior to) the first edge in the block progression dimension of the inline area generated from an associated ruby base container or ruby base annotation.
+If the value is <code>after</code>, then an inline area generated from a ruby text container or ruby text annotation
+is placed after (subsequent to) the second edge in the block progression dimension of the inline area generated from an associated ruby base container or ruby base
+annotation.</p><p>The absolute position of the ruby text container or ruby text annotation is determined
+in accordance to the computed value of the <code>tts:writingMode</code> style property of the region into which the affected content is placed; in particular, the
+mappings defined enumerated by <a href="#rubyPosition-semantics-mapping-table"><b>Table 8-2 – Ruby Position Semantics Mapping by Writing Mode</b></a> apply as further defined by <a href="#cssruby">[CSS Ruby]</a>, §4.1.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>before</code>.</p><a id="rubyPosition-semantics-mapping-table"></a><table class="common"><caption>Table 8-2 – Ruby Position Semantics Mapping by Writing Mode</caption><col width="20%" span="1"><col width="20%" span="1"><col width="20%" span="1"><col width="20%" span="1"><col width="20%" span="1"><col span="1"><tbody><tr><th>tts:rubyPosition</th><th><code>lrtb</code></th><th><code>rltb</code></th><th><code>tbrl</code></th><th><code>tblr</code></th></tr><tr><td><code>before</code></td><td><code>over</code></td><td><code>over</code></td><td><code>right</code></td><td><code>left</code></td></tr><tr><td><code>after</code></td><td><code>under</code></td><td><code>under</code></td><td><code>left</code></td><td><code>right</code></td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Ruby Position Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Ruby Position Example</b></td><td align="right" valign="top">2014-09-20</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add example source and rendering of tts:rubyPosition.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#cssruby">[CSS Ruby]</a>, §4.1, and the examples and example
+renderings shown there apply modulo the mappings defined above.</p></div></div><div class="div3">
+<h4><a id="style-attribute-showBackground"></a>10.2.32 tts:showBackground</h4><p>The <code>tts:showBackground</code> attribute is used to specify
+constraints on when the background color of a region is intended to be
+presented.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-showBackground"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>always</code> |
+<code>whenActive</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>always</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#layout-vocabulary-region"><code>region</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>If the value of this attribute is <code>always</code>, then the
+background color of a region is always rendered when performing presentation
+processing on a visual medium; if the value is <code>whenActive</code>,
+then the background color of a region is rendered only when some
+content is flowed into the region.</p><p>A region satisfies the <code>whenActive</code> case if (1) it is a
+<a href="#terms-temporally-active-region">temporally active region</a> and (2) content is selected into the region,
+where that content is also <a href="#terms-temporally-active">temporally active</a>.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>always</code>.</p><p>The <code>tts:showBackground</code> style is illustrated by the following example.</p><a id="style-attribute-showBackground-example-1"></a><table class="example"><caption>Example Fragment – Show Background</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:extent="265px 100px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style <span class="strong">tts:showBackground="always"</span>/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="before"/&gt;
+  &lt;style tts:textAlign="start"/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:origin="205px 60px"/&gt;
+  &lt;style tts:extent="290px 100px"/&gt;
+  &lt;style tts:backgroundColor="red"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="before"/&gt;
+  &lt;style tts:textAlign="end"/&gt;
+  &lt;style <span class="strong">tts:showBackground="whenActive"</span>/&gt;
+&lt;/region&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#smil3">[SMIL 3.0]</a>,
+§ 7.4.2.</p></div></div><div class="div3">
+<h4><a id="style-attribute-textAlign"></a>10.2.33 tts:textAlign</h4><p>The <code>tts:textAlign</code> attribute is used to specify a style property that
+defines how inline areas are aligned within a containing block area in the inline progression
+direction.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textAlign"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>left</code> |
+<code>center</code> |
+<code>right</code> |
+<code>start</code> |
+<code>end</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>start</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>see prose</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>The <code>tts:textAlign</code> attribute is inheritable only on a <a href="#content-vocabulary-p"><code>p</code></a> element. If not
+specified on a <a href="#content-vocabulary-span"><code>span</code></a> element, then the <code>tts:textAlign</code> style property  does not apply to that
+element, rather, normal inline composition and alignment apply.</p><p>If a <code>tts:textAlign</code> attribute is specified on a <a href="#content-vocabulary-span"><code>span</code></a> element,
+then that <a href="#content-vocabulary-span"><code>span</code></a> element must be processed using
+<a href="#terms-inline-block-display">inline block display</a> semantics for the purpose of presentation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <code>tts:textAlign</code> attribute may be used on a <a href="#content-vocabulary-span"><code>span</code></a> element in order
+to force composition using <a href="#terms-inline-block-display">inline block display</a> semantics and to apply a different alignment
+to the resulting nested block area. For example, a paragraph may be composed using center text alignment, while the text content within the paragraph, if
+wrapped in a span, may be composed using left text alignment.</p></div><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>start</code>.</p><p>The <code>tts:textAlign</code> style is illustrated by the following example.</p><a id="style-attribute-textAlign-example-1"></a><table class="example"><caption>Example Fragment – Text Align</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="355px 43px"/&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:textAlign="start"</span>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:extent="355px 43px"/&gt;
+  &lt;style tts:origin="0px 47px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:textAlign="end"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  Beware the Jabberwock, my son!&lt;br/&gt;
+  The jaws that bite, the claws that catch!
+&lt;/p&gt;
+&lt;p region="r2"&gt;
+  Beware the Jubjub bird, and shun&lt;br/&gt;
+  The frumious Bandersnatch!
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-textAlign-example-1-images"></a><table class="example-images"><caption>Example Rendition – Text Align</caption><tbody><tr><td><img src="images/textAlign.png" alt="TTML textAlign style property"></td></tr></tbody></table><p></p><table border="1" class="ednote" summary="Editorial note: Text Align on Span Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Align on Span Example</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of use of tts:textAlign on a span element.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.16.9.</p></div></div><div class="div3">
+<h4><a id="style-attribute-textCombine"></a>10.2.34 tts:textCombine</h4><p>When a vertical writing mode applies, the <code>tts:textCombine</code> attribute is used to specify a style property that
+determines whether and how multiple nominally non-combining characters are combined so that their glyph areas
+consume the nominal bounding box of a single em square. If a horizontal writing mode applies, then this property is ignored
+for the purpose of presentation processing.</p><p>Combination processing may make use of one or more techniques to obtain the goal of visual combination into an em square. For
+example, half-width variant forms may be selected, a ligature may be selected, a smaller font size may be applied, etc. At a minimum, an
+implementation that supports this style property must be able to select half-width variant forms if available.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textCombine"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>none</code> |
+<code>all</code> |
+[ <code>digits</code> <a href="#style-value-non-negative-integer">&lt;non-negative-integer&gt;</a>? ]
+</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If the specified value of this attribute is <code>none</code>, then no combination processing applies.
+If the specified value of this attribute is <code>all</code>, then all affected characters should be combined.
+If the specified value of this attribute is <code>digits</code>, then all affected characters should be combined if they are a sequence of a digits which length is
+equal to or less than a specified count, or two (2) if no count is specified.</p><p>Combination must not cross an element boundary, a bidirectional boundary, or a non-glyph area boundary.</p><p>This attribute has no impact on or interaction with the nominal layout of glyph areas that constitute a Unicode combining character sequence.</p><table border="1" class="ednote" summary="Editorial note: Text Combine Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Combine Example</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:textCombine.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+that defined by <a href="#css3-wm">[CSS Writing Modes]</a>, § 9.1.</p></div></div><div class="div3">
+<h4><a id="style-attribute-textDecoration"></a>10.2.35 tts:textDecoration</h4><p>The <code>tts:textDecoration</code> attribute is used to specify a style property that
+defines a text decoration effect to apply to glyph areas or other inline
+areas that are generated by content flowed into a region.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textDecoration"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>none</code> |
+[ [
+<code>underline</code> |
+<code>noUnderline</code>
+] || [
+<code>lineThrough</code> |
+<code>noLineThrough</code>
+] || [
+<code>overline</code> |
+<code>noOverline</code>
+] ]
+</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td><a href="#content-vocabulary-span"><code>span</code></a></td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this
+style property, each character child of a <code>p</code> element is
+considered to be enclosed in an anonymous span.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>none</code>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The syntax used above in defining the value of this property is based on the
+value component syntax defined in <a href="#css2">[CSS2]</a>, § 1.4.2.1. In essence,
+one or more of the values separated by <code>||</code> may appear in the property
+value in any order, such as <code>"noUnderline overline lineThrough"</code>.</p></div><p>The <code>tts:textDecoration</code> style is illustrated by the following example.</p><a id="style-attribute-textDecoration-example-1"></a><table class="example"><caption>Example Fragment – Text Decoration</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="385px 82px"/&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:padding="5px 2px"/&gt;
+  &lt;style <span class="strong">tts:textDecoration="underline"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  The sea was wet&lt;span <span class="strong">tts:textDecoration="noUnderline"</span>&gt; as &lt;/span&gt;wet
+  &lt;span <span class="strong">tts:textDecoration="noUnderline"</span>&gt;
+    could be,&lt;br/&gt;
+    The sand was dry as dry.&lt;br/&gt;
+    &lt;span <span class="strong">tts:textDecoration="lineThrough"</span>&gt;There weren't any&lt;/span&gt;
+    You &lt;span <span class="strong">tts:textDecoration="lineThrough"</span>&gt;couldn't&lt;/span&gt;
+    could not see a cloud&lt;br/&gt;
+    Because no cloud was in the sky.
+  &lt;/span&gt;
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-textDecoration-example-1-images"></a><table class="example-images"><caption>Example Rendition – Text Decoration</caption><tbody><tr><td><img src="images/textDecoration.png" alt="TTML textDecoration style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.17.4.</p></div></div><div class="div3">
+<h4><a id="style-attribute-textEmphasis"></a>10.2.36 tts:textEmphasis</h4><p>The <code>tts:textEmphasis</code> attribute is used to specify a style property that
+determines whether and how text emphasis marks are presented on affected content.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textEmphasis"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+[
+<a href="#style-value-emphasisStyle">&lt;emphasisStyle&gt;</a> ||
+<a href="#style-value-emphasisColor">&lt;emphasisColor&gt;</a> ||
+<a href="#style-value-emphasisPosition">&lt;emphasisPosition&gt;</a>
+]
+</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous (color only)</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If the specified value of this attribute is <code>auto</code>, then it must be interpreted as if
+<code>auto</code> were specified for both emphasis style and emphasis position components.</p><p>If no emphasis style is specified,
+then the emphasis style must be interpreted as if a style of <code>auto</code> were specified.
+If no emphasis color is specified,
+then the emphasis color must be interpreted as if a color of <code>current</code> were specified.
+If no emphasis position is specified,
+then the emphasis position must be interpreted as if a position of <code>auto</code> were specified.</p><table border="1" class="ednote" summary="Editorial note: Text Emphasis Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Emphasis Example</b></td><td align="right" valign="top">2015-01-05</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:textEmphasis.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+that defined by <a href="#css3-decoration">[CSS Text Decoration]</a>, § 3.</p></div></div><div class="div3">
+<h4><a id="style-attribute-textOrientation"></a>10.2.37 tts:textOrientation</h4><p>The <code>tts:textOrientation</code> attribute is used to specify a style property that
+defines a text orientation to apply to glyphs that are selected for glyph areas generated
+by content flowed into a region to which a vertical writing mode applies.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textOrientation"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>mixed</code> |
+<code>sideways</code> |
+<code>sidewaysLeft</code> |
+<code>sidewaysRight</code> |
+<code>upright</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>mixed</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If the value of this attribute is <code>mixed</code>, then, in vertical writing modes,
+glyphs from horizontal scripts are set sideways, i.e., 90° clockwise from
+their nominal orientation in horizontal text, while glyphs from vertical scripts are not
+affected.</p><p>If the value of this attribute is <code>sidewaysLeft</code>, then, in vertical writing modes,
+glyphs from horizontal scripts are set sideways with 90° counter-clockwise rotation.</p><p>If the value of this attribute is <code>sidewaysRight</code>, then, in vertical writing modes,
+glyphs from horizontal scripts are set sideways with 90° clockwise rotation.</p><p>If the value of this attribute is <code>sideways</code>, then, in vertical writing modes,
+glyphs from horizontal scripts are set sideways, either 90° clockwise or
+90° counter-clockwise, according to whether the writing mode is
+<code>tbrl</code> or <code>tblr</code>, respectively. Glyphs from vertical scripts are not
+affected.</p><p>If the value of this attribute is <code>upright</code>, then, in vertical writing modes,
+glyphs from horizontal scripts are set upright, i.e., using their
+nominal orientation in horizontal text, while glyphs from vertical scripts are not
+affected. In addition, for purposes of bidirectional processing, this value causes all
+affected characters to be treated as strong left-to-right, i.e., to be treated as if
+a <code>tts:direction</code> of <code>ltr</code> and <code>tts:unicodeOverride</code> of
+<code>override</code> were applied.</p><p>If a vertical writing mode does not apply, then this style property has no effect.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>mixed</code>.</p><p>The <code>tts:textOrientation</code> style is illustrated by the following
+example.</p><table border="1" class="ednote" summary="Editorial note: Text Orientation Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Orientation Example</b></td><td align="right" valign="top">2013-08-24</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:textOrientation.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#css3-wm">[CSS Writing Modes]</a>,
+§ 5.1.</p></div></div><div class="div3">
+<h4><a id="style-attribute-textOutline"></a>10.2.38 tts:textOutline</h4><p>The <code>tts:textOutline</code> attribute is used to specify a style property that
+defines a text outline effect to apply to glyphs that are selected for glyph areas generated
+by content flowed into a region.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textOutline"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>none</code> |
+<a href="#style-value-color">&lt;color&gt;</a>?
+<a href="#style-value-length">&lt;length&gt;</a>
+<a href="#style-value-length">&lt;length&gt;</a>?
+</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>relative to this element's font size</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>The value of this attribute consists of an optional <a href="#style-value-color">&lt;color&gt;</a> term
+followed by one or two <a href="#style-value-length">&lt;length&gt;</a> terms.  If a <em>color</em> term is
+present, then it denotes the outline color; if no <em>color</em> term is
+present, the computed value of the <code>tts:color</code> applies.  The first
+<em>length</em> term denotes the outline thickness and the second length
+term, if present, indicates the blur radius.</p><p>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used to express thickness and blur radius must be non-negative.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When a <a href="#style-value-length">&lt;length&gt;</a> expressed in
+cells is used in a <code>tts:textOutline</code> value,
+the cell's dimension in the block progression dimension applies.
+For example, if text outline thickness is specified as 0.1c, the cell resolution
+is 20 by 10, and the extent of the <a href="#terms-root-container-region">root container region</a> is 640 by 480, then the
+outline thickness will be a nominal 480 / 10 * 0.1 pixels, i.e., 4.8px,
+without taking into account rasterization effects.</p></div><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>none</code>.</p><p>The <code>tts:textOutline</code> style is illustrated by the following
+example.</p><a id="style-attribute-textOutline-example-1"></a><table class="example"><caption>Example Fragment – Text Outline</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:backgroundColor="transparent"/&gt;
+  &lt;style tts:color="yellow"/&gt;
+  &lt;style <span class="strong">tts:textOutline="black 2px 0px"</span>/&gt;
+  &lt;style tts:fontFamily="proportionalSansSerif"/&gt;
+  &lt;style tts:fontSize="24px"/&gt;
+&lt;/region&gt;
+...
+&lt;p&gt;
+  How doth the little crocodile&lt;br/&gt;
+  Improve its shining tail,&lt;br/&gt;
+  And pour the waters of the Nile&lt;br/&gt;
+  On every golden scale!&lt;br/&gt;
+  How cheerfully he seems to grin,&lt;br/&gt;
+  How neatly spreads his claws,&lt;br/&gt;
+  And welcomes little fishes in,&lt;br/&gt;
+  With gently smiling jaws!
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-textOutline-example-1-images"></a><table class="example-images"><caption>Example Rendition – Text Outline</caption><tbody><tr><td><img src="images/textOutline.png" alt="textOutline style property"></td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-attribute-textShadow"></a>10.2.39 tts:textShadow</h4><p>The <code>tts:textShadow</code> attribute is used to specify a style property that
+defines one or more text shadow decorations to apply to glyphs that are selected for glyph areas generated
+by content flowed into a region.</p><p>If both <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a> and <code>tts:textShadow</code> attributes
+are specified on an element and <code>tts:textShadow</code> is a supported property,
+then the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a> attribute must be ignored for the purpose of presentation processing.</p><p>If multiple text shadows apply, then they are drawn in the specified order immediately prior to drawing the glyph area to which they apply.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-textShadow"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>none</code> |
+[ <a href="#style-value-shadow">&lt;shadow&gt;</a> ]#
+</td></tr><tr><td><em>Initial:</em></td><td><code>none</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>relative to this element's font size</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>none</code>.</p><table border="1" class="ednote" summary="Editorial note: Text Shadow Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Text Shadow Example</b></td><td align="right" valign="top">2015-01-08</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:textShadow.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property represented by this attribute are based upon 
+that defined by <a href="#css3-decoration">[CSS Text Decoration]</a>, § 4.</p></div></div><div class="div3">
+<h4><a id="style-attribute-unicodeBidi"></a>10.2.40 tts:unicodeBidi</h4><p>The <code>tts:unicodeBidi</code> attribute is used to specify a style property that
+defines a directional embedding or override according to
+the Unicode bidirectional algorithm.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-unicodeBidi"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>normal</code> |
+<code>embed</code> |
+<code>bidiOverride</code>
+</td></tr><tr><td><em>Initial:</em></td><td>
+<code>normal</code>
+</td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>normal</code>.</p><p>The <code>tts:unicodeBidi</code> style is illustrated by the following example.</p><a id="style-attribute-unicodeBidi-example-1"></a><table class="example"><caption>Example Fragment – Unicode Bidirectionality</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="265px 84px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:textAlign="center"/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  Little birds are playing&lt;br/&gt;
+  Bagpipes on the shore,&lt;br/&gt;
+  &lt;span <span class="strong">tts:unicodeBidi="bidiOverride"</span> tts:direction="rtl"&gt;where the tourists snore.&lt;/span&gt;
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-unicodeBidi-example-1-images"></a><table class="example-images"><caption>Example Rendition – Unicode Bidirectionality</caption><tbody><tr><td>
+<img src="images/unicodeBidi.png" alt="TTML unicodeBidi style property">
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.29.6.</p></div></div><div class="div3">
+<h4><a id="style-attribute-visibility"></a>10.2.41 tts:visibility</h4><p>The <code>tts:visibility</code> attribute is used to specify a style property that
+defines whether generated areas are visible or not when rendered on a visual
+presentation medium.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-visibility"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>visible</code> |
+<code>hidden</code>
+</td></tr><tr><td><em>Initial:</em></td><td>
+<code>visible</code>
+</td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#layout-vocabulary-region"><code>region</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>The <code>tts:visibility</code> style has no affect on content layout or
+composition, but merely determines whether composed content is visible or not.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>visible</code>.</p><p>The <code>tts:visibility</code> style is illustrated by the following example.</p><a id="style-attribute-visibility-example-1"></a><table class="example"><caption>Example Fragment – Visibility</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="398px 121px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1" dur="4s"&gt;
+  &lt;span <span class="strong">tts:visibility="hidden"</span>&gt;
+    &lt;set begin="1s" <span class="strong">tts:visibility="visible"</span>/&gt;
+    Curiouser
+  &lt;/span&gt;
+  &lt;span <span class="strong">tts:visibility="hidden"</span>&gt;
+    &lt;set begin="2s" <span class="strong">tts:visibility="visible"</span>/&gt;
+    and
+  &lt;/span&gt;
+  &lt;span <span class="strong">tts:visibility="hidden"</span>&gt;
+    &lt;set begin="3s" <span class="strong">tts:visibility="visible"</span>/&gt;
+    curiouser!
+  &lt;/span&gt;
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-visibility-example-1-images"></a><table class="example-images"><caption>Example Rendition – Visibility</caption><tbody><tr><td>
+<img src="images/visibility_0.png" alt="TTML visibility style property - [0,1)">
+</td></tr><tr><td>
+<img src="images/visibility_1.png" alt="TTML visibility style property - [1,2)">
+</td></tr><tr><td>
+<img src="images/visibility_2.png" alt="TTML visibility style property - [2,3)">
+</td></tr><tr><td>
+<img src="images/visibility_3.png" alt="TTML visibility style property - [3,4)">
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.30.17.</p></div></div><div class="div3">
+<h4><a id="style-attribute-width"></a>10.2.42 tts:width</h4><p>The <code>tts:width</code> attribute is used to specify the
+<em>width</em> of an area generated by content flowed into a region.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The term <em>width</em> is interpreted in a writing mode relative manner
+such that <em>width</em> always corresponds to a measure in the inline
+progression direction. Therefore, in horizontal writing modes, <em>width</em> expresses a horizontal measure,
+while, in vertical writing mode, <em>width</em> expresses a vertical measure,
+where horizontal and vertical are always interpreted in an absolute sense.</p></div><p>If a <code>tts:width</code> attribute is specified on a <a href="#content-vocabulary-span"><code>span</code></a> element,
+then that <a href="#content-vocabulary-span"><code>span</code></a> element must be processed using
+<a href="#terms-inline-block-display">inline block display</a> semantics for the purpose of presentation processing.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-width"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<a href="#style-value-measure">&lt;measure&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>,
+<a href="#embedded-content-vocabulary-image"><code>image</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>see prose</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous</td></tr></tbody></table><p>If a <a href="#style-value-measure">&lt;measure&gt;</a> is expressed as a <a href="#style-value-length">&lt;length&gt;</a> value, then it must be non-negative.</p><p>The <code>tts:width</code> style is illustrated by the following example.</p><table border="1" class="ednote" summary="Editorial note: Width Percentage"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Width Percentage</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Specify resolution of percentage value.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: Width Example"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Width Example</b></td><td align="right" valign="top">2014-11-29</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert example fragment and image of tts:width.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.15.14, and <a href="#css3-box">[CSS Box Model]</a>, § 9</p></div></div><div class="div3">
+<h4><a id="style-attribute-wrapOption"></a>10.2.43 tts:wrapOption</h4><p>The <code>tts:wrapOption</code> attribute is used to specify a style property that
+defines whether or not automatic line wrapping (breaking) applies within the context of
+the affected element.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-wrapOption"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>wrap</code> |
+<code>noWrap</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>wrap</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#content-vocabulary-span"><code>span</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>yes</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>For the purpose of determining applicability of this style property,
+each character child of a <code>p</code> element is considered to be enclosed in an anonymous
+span.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>wrap</code>.</p><p>The <code>tts:wrapOption</code> style is illustrated by the following example.</p><a id="style-attribute-wrapOption-example-1"></a><table class="example"><caption>Example Fragment – Wrap Option</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="192px 117px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:displayAlign="after"/&gt;
+  &lt;style tts:overflow="hidden"/&gt;
+  &lt;style <span class="strong">tts:wrapOption="noWrap"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p&gt;
+  I'll tell thee everything I can:&lt;br/&gt;
+  There's little to relate.&lt;br/&gt;
+  I saw an aged aged man,&lt;br/&gt;
+  A-sitting on a gate.
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-wrapOption-example-1-images"></a><table class="example-images"><caption>Example Rendition – Wrap Option</caption><tbody><tr><td><img src="images/wrapOption.png" alt="TTML wrapOption style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.16.13.</p></div></div><div class="div3">
+<h4><a id="style-attribute-writingMode"></a>10.2.44 tts:writingMode</h4><p>The <code>tts:writingMode</code> attribute is used to specify a style property that
+defines the block and inline progression directions to be used for the purpose of
+stacking block and inline areas within a region area.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-writingMode"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>lrtb</code> |
+<code>rltb</code> |
+<code>tbrl</code> |
+<code>tblr</code> |
+<code>lr</code> |
+<code>rl</code> |
+<code>tb</code>
+</td></tr><tr><td><em>Initial:</em></td><td><code>lrtb</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#layout-vocabulary-region"><code>region</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete</td></tr></tbody></table><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the value <code>lrtb</code>.</p><p>The <code>tts:writingMode</code> style is illustrated by the following example.</p><a id="style-attribute-writingMode-example-1"></a><table class="example"><caption>Example Fragment – Writing Mode</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:extent="50px 570px"/&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:padding="10px 3px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:writingMode="tbrl"</span>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:extent="310px 50px"/&gt;
+  &lt;style tts:origin="70px 120px"/&gt;
+  &lt;style tts:padding="10px 3px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:writingMode="rltb"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  I sometimes dig for buttered rolls,&lt;br/&gt;
+  Or set limed twigs for crabs:
+&lt;/p&gt;
+&lt;p region="r2" tts:direction="rtl" tts:unicodeBidi="bidiOverride"&gt;
+  I sometimes search the grassy knolls for the wheels of Hansom-cabs.
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="style-attribute-writingMode-example-1-images"></a><table class="example-images"><caption>Example Rendition – Writing Mode</caption><tbody><tr><td><img src="images/writingMode.png" alt="TTML writingMode style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the second paragraph in the above example that targets region
+<code>r2</code>, the <code>tts:unicodeBidi</code> and
+<code>tts:direction</code> properties are set to
+<code>bidiOverride</code> and <code>rtl</code>, respectively, in order
+to override the normally left-to-right directionality of characters in
+the Latin script.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.29.7.</p></div></div><div class="div3">
+<h4><a id="style-attribute-zIndex"></a>10.2.45 tts:zIndex</h4><p>The <code>tts:zIndex</code> attribute is used to specify a style property that
+defines the front-to-back ordering of region areas in the case that they overlap.</p><p>This attribute may be specified by any
+element type
+that permits use of attributes in the TT Style Namespace; however, this attribute applies
+as a style property only to those element types indicated in the following table.</p><a id="style-property-details-zIndex"></a><table class="common"><col width="25%" span="1"><col span="1"><tbody><tr><td><em>Values:</em></td><td>
+<code>auto</code> |
+<a href="#style-value-integer">&lt;integer&gt;</a>
+</td></tr><tr><td><em>Initial:</em></td><td><code>auto</code></td></tr><tr><td><em>Applies to:</em></td><td>
+<a href="#layout-vocabulary-region"><code>region</code></a>
+</td></tr><tr><td><em>Inherited:</em></td><td>no</td></tr><tr><td><em>Percentages:</em></td><td>N/A</td></tr><tr><td><em>Animatable:</em></td><td>discrete, continuous (over integral values only)</td></tr></tbody></table><p>If two areas are associated with the same Z-index value, then, if those areas
+overlap in space, the area(s) generated by lexically subsequent elements must be
+rendered over area(s) generated by lexically prior elements, where lexical
+order is defined as the postorder traversal of a <a href="#terms-document-instance">document instance</a>.</p><p>The semantics of the value <code>auto</code> are those defined by
+<a href="#xsl11">[XSL 1.1]</a>, § 7.30.18, where the <code>tt</code> element
+is considered to establish the root stacking context.</p><p>If a computed value of the property associated with this attribute is not supported,
+then a <a href="#terms-presentation-processor">presentation processor</a> must use the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
+the computed z-index and the supported z-index is minimized. If there are multiple closest supported values equally distant from
+the computed value, then the value least distant from 0, i.e., closest to the base stack level of the current stacking context, is used.</p></div><p>The <code>tts:zIndex</code> style is illustrated by the following example.</p><a id="style-attribute-zIndex-example-1"></a><table class="example"><caption>Example Fragment – Z Index</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  &lt;style tts:origin="0px 0px"/&gt;
+  &lt;style tts:extent="400px 100px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:zIndex="0"</span>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r2"&gt;
+  &lt;style tts:origin="100px 60px"/&gt;
+  &lt;style tts:extent="400px 100px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="red"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:textAlign="end"/&gt;
+  &lt;style <span class="strong">tts:zIndex="1"</span>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r3"&gt;
+  &lt;style tts:origin="0px 120px"/&gt;
+  &lt;style tts:extent="400px 100px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="black"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style <span class="strong">tts:zIndex="2"</span>/&gt;
+&lt;/region&gt;
+&lt;region xml:id="r4"&gt;
+  &lt;style tts:origin="100px 180px"/&gt;
+  &lt;style tts:extent="400px 100px"/&gt;
+  &lt;style tts:padding="5px"/&gt;
+  &lt;style tts:backgroundColor="red"/&gt;
+  &lt;style tts:color="white"/&gt;
+  &lt;style tts:textAlign="end"/&gt;
+  &lt;style <span class="strong">tts:zIndex="3"</span>/&gt;
+&lt;/region&gt;
+...
+&lt;p region="r1"&gt;
+  I passed by his garden, and marked, with one eye,&lt;br/&gt;
+  How the Owl and the Panther were sharing a pie.
+&lt;/p&gt;
+&lt;p region="r2"&gt;
+  The Panther took pie-crust, and gravy, and meat,&lt;br/&gt;
+  While the Owl had the dish as its share of the treat.
+&lt;/p&gt;
+&lt;p region="r3"&gt;
+  When the pie was all finished, the Owl, as a boon,&lt;br/&gt;
+  Was kindly permitted to pocket the spoon:
+&lt;/p&gt;
+&lt;p region="r4"&gt;
+  While the Panther received knife and fork&lt;br/&gt;
+  with a growl,&lt;br/&gt;
+  And concluded the banquet by...
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><p></p><a id="style-attribute-zIndex-example-1-images"></a><table class="example-images"><caption>Example Rendition – Z Index</caption><tbody><tr><td><img src="images/zIndex.png" alt="TTML zIndex style property"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the style property
+represented by this attribute are based upon that defined by <a href="#xsl11">[XSL 1.1]</a>,
+§ 7.30.18.</p></div></div></div><div class="div2">
+<h3><a id="styling-style-value-expressions"></a>10.3 Styling Value Expressions</h3><p>Style property values include the use of the following expressions:</p><ul><li><p><a href="#style-value-alpha"><b>10.3.1 &lt;alpha&gt;</b></a></p></li><li><p><a href="#style-value-borderColor"><b>10.3.2 &lt;borderColor&gt;</b></a></p></li><li><p><a href="#style-value-borderStyle"><b>10.3.3 &lt;borderStyle&gt;</b></a></p></li><li><p><a href="#style-value-borderWidth"><b>10.3.4 &lt;borderWidth&gt;</b></a></p></li><li><p><a href="#style-value-color"><b>10.3.5 &lt;color&gt;</b></a></p></li><li><p><a href="#style-value-digit"><b>10.3.6 &lt;digit&gt;</b></a></p></li><li><p><a href="#style-value-emphasisColor"><b>10.3.7 &lt;emphasisColor&gt;</b></a></p></li><li><p><a href="#style-value-emphasisStyle"><b>10.3.8 &lt;emphasisStyle&gt;</b></a></p></li><li><p><a href="#style-value-emphasisPosition"><b>10.3.9 &lt;emphasisPosition&gt;</b></a></p></li><li><p><a href="#style-value-familyName"><b>10.3.10 &lt;familyName&gt;</b></a></p></li><li><p><a href="#style-value-genericFamilyName"><b>10.3.11 &lt;genericFamilyName&gt;</b></a></p></li><li><p><a href="#style-value-hexDigit"><b>10.3.12 &lt;hexDigit&gt;</b></a></p></li><li><p><a href="#style-value-integer"><b>10.3.13 &lt;integer&gt;</b></a></p></li><li><p><a href="#style-value-length"><b>10.3.14 &lt;length&gt;</b></a></p></li><li><p><a href="#style-value-measure"><b>10.3.15 &lt;measure&gt;</b></a></p></li><li><p><a href="#style-value-namedColor"><b>10.3.16 &lt;namedColor&gt;</b></a></p></li><li><p><a href="#style-value-non-negative-integer"><b>10.3.17 &lt;non-negative-integer&gt;</b></a></p></li><li><p><a href="#style-value-number"><b>10.3.18 &lt;number&gt;</b></a></p></li><li><p><a href="#style-value-percentage"><b>10.3.19 &lt;percentage&gt;</b></a></p></li><li><p><a href="#style-value-position"><b>10.3.20 &lt;position&gt;</b></a></p></li><li><p><a href="#style-value-shadow"><b>10.3.21 &lt;shadow&gt;</b></a></p></li></ul><p>In the syntax representations defined in this section, no
+linear whitespace (LWSP) is implied or permitted between tokens
+unless explicitly specified.</p><div class="div3">
+<h4><a id="style-value-alpha"></a>10.3.1 &lt;alpha&gt;</h4><p>An &lt;alpha&gt; expression is used to express an opacity value,
+where	0 means fully transparent and 1 means fully opaque.</p><a id="alpha-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;alpha&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;alpha&gt;
+  : <em>float</em>
+</pre></div>
+</td></tr></tbody></table><p>In the above syntax representation, the syntactic element
+<em><code>float</code></em> must adhere to the lexical
+representation defined by <a href="#xsd-2">[XML Schema Part 2]</a>&nbsp;§
+3.2.4.1. If the value represented is less than 0.0,
+then it must be interpreted as equal to 0.0; similarly, if the value
+represented is greater than 1.0, then it must be interpreted as
+1.0. The value NaN must be interpreted as 0.0.</p><p>A specified value for &lt;alpha&gt; should not be <code>NaN</code>,
+less than 0, or greater than 1.</p><p>If a <a href="#terms-presentation-processor">presentation processor</a> does not support a specific,
+valid opacity value, then it must interpret it as being equal to the
+closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
+the computed opacity and the supported opacity is minimized. If there are multiple closest supported values equally distant from
+the computed value, then the value most distant from 0, i.e., the greatest opacity, is used.</p></div></div><div class="div3">
+<h4><a id="style-value-borderColor"></a>10.3.2 &lt;borderColor&gt;</h4><p>A &lt;borderColor&gt; expression is used to express the color of one
+or more borders.</p><a id="borderColor-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;borderColor&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;borderColor&gt;
+  : <a href="#style-value-color">&lt;color&gt;</a>
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-value-borderStyle"></a>10.3.3 &lt;borderStyle&gt;</h4><p>A &lt;borderStyle&gt; expression is used to express the style of one
+or more borders.</p><a id="borderStyle-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;borderStyle&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;borderStyle&gt;
+  : none
+  | dotted
+  | dashed
+  | solid
+  | double
+</pre></div>
+</td></tr></tbody></table><p>The interpretation of <code>dotted</code>, <code>dashed</code>, and <code>double</code> are considered
+to be implementation dependent.</p><p>If an implementation does not recognize or otherwise distinguish one of these border style values, then
+it must be interpreted as if a style of <code>solid</code> were specified; as such, an implementation that
+supports borders must minimally support the <code>solid</code> value.</p></div><div class="div3">
+<h4><a id="style-value-borderWidth"></a>10.3.4 &lt;borderWidth&gt;</h4><p>A &lt;borderWidth&gt; expression is used to express the width of one
+or more borders.</p><a id="borderWidth-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;borderWidth&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;borderWidth&gt;
+  : thin
+  | medium
+  | thick
+  | <a href="#style-value-length">&lt;length&gt;</a>
+</pre></div>
+</td></tr></tbody></table><p>The interpretation of <code>thin</code>, <code>medium</code>, and <code>thick</code> are considered
+to be implementation dependent; however, the resolved lengths of these widths must adhere to the following
+constraints: width(thin) &lt; width(medium); width(medium) &lt; width(thick).</p><p>If a border width is expressed as a <a href="#style-value-length">&lt;length&gt;</a>,
+then it must not take the form of a percentage value; i.e., it must take the form of a scalar value.</p></div><div class="div3">
+<h4><a id="style-value-color"></a>10.3.5 &lt;color&gt;</h4><p>A &lt;color&gt; expression is used to specify a named color, exact RGB color triple,
+or exact RGBA color tuple, where the alpha component, if expressed,
+is maximum (255) at 100% opacity
+and minimum (0) at 0% opacity, and where the applicable color space is
+defined by <a href="#srgb">[SRGB]</a>.</p><a id="color-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;color&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;color&gt;
+  : "#" rrggbb
+  | "#" rrggbbaa
+  | "rgb" "(" r-value "," g-value "," b-value ")"
+  | "rgba" "(" r-value "," g-value "," b-value "," a-value ")"
+  | <a href="#style-value-namedColor">&lt;namedColor&gt;</a>
+
+rrggbb
+  :  <a href="#style-value-hexDigit">&lt;hexDigit&gt;</a>{6}
+
+rrggbbaa
+  :  <a href="#style-value-hexDigit">&lt;hexDigit&gt;</a>{8}
+
+r-value | g-value | b-value | a-value
+  : component-value
+
+component-value
+  : non-negative-integer                    // valid range: [0,255]
+
+non-negative-integer
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+</pre></div>
+</td></tr></tbody></table><p>When expressing RGB component values, these values are considered
+to <span class="strong">not</span> be premultiplied by alpha.</p><p>For the purpose of performing presentation processing such that
+non-opaque or non-transparent alpha or opacity values apply, then the
+semantics of compositing functions are defined with respect to the use of
+the <a href="#srgb">[SRGB]</a> color space for both inputs and outputs of
+the composition function.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of <a href="#srgb">[SRGB]</a> for the stated semantics of
+composition is not meant to prevent an actual processor from using some
+other color space either for internal or external purposes. For
+example, a <a href="#terms-presentation-processor">presentation processor</a> may ultimately convert the SRGB values
+used here to the YUV color space for rendition on a television device.</p></div><p>If a <a href="#terms-presentation-processor">presentation processor</a> does not support a specific,
+valid color or alpha value, then it must interpret it as being equal
+to the closest supported value.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this context, the phrase <em>closest supported value</em> means the value for which the Euclidean distance between
+the computed color and alpha and the supported color and alpha in the RGB color space is minimized. If there are multiple closest supported values equally distant from
+the computed value, then the value least distant from opaque black <code>rgb(0,0,0,255)</code>, i.e., the closest to opaque black, is used.</p></div></div><div class="div3">
+<h4><a id="style-value-digit"></a>10.3.6 &lt;digit&gt;</h4><p>A &lt;digit&gt; is used to express integers and other types of numbers or tokens.</p><a id="digit-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;digit&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;digit&gt;
+  : "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-value-emphasisColor"></a>10.3.7 &lt;emphasisColor&gt;</h4><p>An &lt;emphasisColor&gt; expression is used to express the color of text
+emphasis marks.</p><a id="emphasisColor-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;emphasisColor&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;emphasisColor&gt;
+  : current
+  | <a href="#style-value-color">&lt;color&gt;</a>
+</pre></div>
+</td></tr></tbody></table><dl><dt class="label"><code>current</code></dt><dd><p>Equivalent to the computed value of <a href="#style-attribute-color"><code>tts:color</code></a> of the affected text.</p></dd><dt class="label"><a href="#style-value-color">&lt;color&gt;</a></dt><dd><p>The specified color.</p></dd></dl><p>If an implementation does not recognize or otherwise distinguish emphasis color value, then
+it must be interpreted as if a style of <code>current</code> were specified; as such, an implementation that
+supports text emphasis marks must minimally support the <code>current</code> value.</p></div><div class="div3">
+<h4><a id="style-value-emphasisStyle"></a>10.3.8 &lt;emphasisStyle&gt;</h4><p>An &lt;emphasisStyle&gt; expression is used to express the style of text
+emphasis marks.</p><a id="emphasisStyle-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;emphasisStyle&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;emphasisStyle&gt;
+  : none
+  | auto 
+  | [ filled | open ] || [ circle | dot | sesame ]
+  | <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
+</pre></div>
+</td></tr></tbody></table><p>The semantics of text emphasis style values are defined as follows:</p><dl><dt class="label"><code>none</code></dt><dd><p>No text emphasis mark.</p></dd><dt class="label"><code>auto</code></dt><dd><p>If a vertical writing mode applies, then equivalent to <code>filled sesame</code>; otherwise,
+equivalent to <code>filled circle</code>.</p></dd><dt class="label"><code>filled</code></dt><dd><p>Emphasis mark is filled with emphasis color.</p></dd><dt class="label"><code>open</code></dt><dd><p>Emphasis mark is not filled, i.e., its outline is stroked with the emphasis color, but it is not filled.</p></dd><dt class="label"><code>circle</code></dt><dd><p>Emphasis mark is a circle. If filled, then equivalent to U+25CF '●'; if open, then equivalent to U+25CB '○'</p></dd><dt class="label"><code>dot</code></dt><dd><p>Emphasis mark is a dot. If filled, then equivalent to U+2022 '•'; if open, then equivalent to U+25E6 '◦'</p></dd><dt class="label"><code>sesame</code></dt><dd><p>Emphasis mark is a sesame. If filled, then equivalent to U+FE45 '﹅'; if open, then equivalent to U+FE46 '﹆'</p></dd><dt class="label"><a href="#content-value-quoted-string">&lt;quoted-string&gt;</a></dt><dd><p>Emphasis mark is the first grapheme cluster of string, with remainder of string ignored.</p></dd></dl><p>If only <code>filled</code> or <code>open</code> is specified, then it is equivalent to <code>filled circle</code> and <code>open circle</code>, respectively.</p><p>If only <code>circle</code>, <code>dot</code>, or <code>sesame</code> is specified, then it is equivalent to <code>filled circle</code>, <code>filled dot</code>, and
+<code>filled sesame</code>, respectively.</p><p>If an implementation does not recognize or otherwise distinguish an emphasis style value, then
+it must be interpreted as if a style of <code>auto</code> were specified; as such, an implementation that
+supports text emphasis marks must minimally support the <code>auto</code> value.</p></div><div class="div3">
+<h4><a id="style-value-emphasisPosition"></a>10.3.9 &lt;emphasisPosition&gt;</h4><p>An &lt;emphasisPosition&gt; expression is used to express the position of text
+emphasis marks.</p><a id="emphasisPosition-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;emphasisPosition&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;emphasisPosition&gt;
+  : auto
+  | before
+  | after
+  | outside
+</pre></div>
+</td></tr></tbody></table><dl><dt class="label"><code>auto</code></dt><dd><p>If the containing block area consists of exactly two line areas, then equivalent to <code>outside</code>; otherwise,
+equivalent to <code>before</code>.</p></dd><dt class="label"><code>before</code></dt><dd><p>Towards the before edge of the affected glyph areas. If a horizontal writing mode applies, then this is towards the
+top of the glyph areas. If a vertical writing mode applies, then this is either towards the right or left of the glyph
+areas, according to whether <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a> resolves to
+<code>tbrl</code> or <code>tblr</code>, respectively.</p></dd><dt class="label"><code>after</code></dt><dd><p>Towards the after edge of the affected glyph areas. If a horizontal writing mode applies, then this is towards the
+bottom of the glyph areas. If a vertical writing mode applies, then this is either towards the left or right of the glyph
+areas, according to whether <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a> resolves to
+<code>tbrl</code> or <code>tblr</code>, respectively.</p></dd><dt class="label"><code>outside</code></dt><dd><p>Equivalent to <code>before</code> for all but the last affected line area; otherwise, equivalent to <code>after</code>
+for the last affected line area.</p></dd></dl><p>If an implementation does not recognize or otherwise distinguish an emphasis position value, then
+it must be interpreted as if a position of <code>auto</code> were specified; as such, an implementation that
+supports text emphasis marks must minimally support the <code>auto</code> value.</p></div><div class="div3">
+<h4><a id="style-value-familyName"></a>10.3.10 &lt;familyName&gt;</h4><p>A &lt;familyName&gt; expression specifies a font family name.</p><a id="familyName-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;familyName&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;familyName&gt;
+  : unquoted-string
+  | <a href="#content-value-quoted-string">&lt;quoted-string&gt;</a>
+
+unquoted-string
+  : identifier ( lwsp identifier )*
+
+lwsp
+  : ( ' ' | '\t' | '\n' | '\r' )+
+
+identifier
+  : [-]? identifier-start identifier-following*
+
+identifier-start
+  : [_a-zA-Z]
+  | non-ascii-or-c1
+  | escape
+
+identifier-following
+  : [_a-zA-Z0-9-]
+  | non-ascii-or-c1
+  | escape
+
+non-ascii-or-c1
+  : [^\0-\237]
+
+escape
+  : '\\' <em>char</em>
+</pre></div>
+
+</td></tr></tbody></table><p>In addition to adhering to the syntax rules specified above, the following semantic rules apply:</p><ul><li><p>the semantic value of a &lt;familyName&gt; expression is the semantic value of its <code>unquoted-string</code> or <code>quoted-string</code>
+non-terminal, according to whichever applies;</p></li><li><p>the semantic value of an <code>unquoted-string</code> non-terminal is a pair <code>&lt;</code><em>quoted</em>, <em>content</em><code>&gt;</code>,
+where <em>quoted</em> is a boolean <code>false</code>, and
+where <em>content</em> is the result of appending the value of each <code>identifier</code>
+non-terminal, in lexical order, where the value of each identifier is preceded by a single SPACE (U+0020) character if it is not the first
+identifier;</p></li><li><p>the semantic value of a <code>quoted-string</code> non-terminal is a pair <code>&lt;</code><em>quoted</em>, <em>content</em><code>&gt;</code>,
+where <em>quoted</em> is a boolean <code>true</code>, and
+where <em>content</em> is the unquoted content of the quoted string, i.e., the sequence of characters between the delimiting quotes.</p></li><li><p>the semantic value of an <code>escape</code> non-terminal is the value of the escaped <code>char</code>;</p></li><li><p>a &lt;familyName&gt; that takes the form of an <code>unquoted-string</code> that contains an <code>identifier</code> that
+starts with two <code>-</code> HYPHEN-MINUS (U+002D) characters must be considered to be invalid;</p></li><li><p>a &lt;familyName&gt; that takes the form of an <code>unquoted-string</code> that contains a single <code>identifier</code> that
+matches (by case sensitive comparison) a &lt;genericFamilyName&gt; must be interpreted as that &lt;genericFamilyName&gt;;</p></li><li><p>a &lt;familyName&gt; that takes the form of a <code>quoted-string</code> whose content (unquoted value)
+matches (by case sensitive comparison) a &lt;genericFamilyName&gt; must not be interpreted as that &lt;genericFamilyName&gt;, but as
+the actual name of a non-generic font family.</p></li><li><p>The syntactic element <em><code>char</code></em> is to be interpreted according
+to the <code>Char</code> production defined by <a href="#xml10">[XML 1.0]</a>&nbsp;§2.2.</p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>The <code>{unicode}</code> escape mechanism defined by <a href="#css2">[CSS2]</a>&nbsp;§4.1.1
+is not supported by this syntax; rather, authors are expected to either (1) directly encode the character
+using the document encoding or (2) use an XML character reference according to
+<a href="#xml10">[XML 1.0]</a>&nbsp;§4.1. When a syntactically significant character needs to be used
+without its normal syntactic interpretation, it may be be escaped using the backslash
+(reverse solidus) <code>escape</code> non-terminal specified above.</p><p>When using the backslash (reverse solidus) <code>escape</code> non-terminal, the above syntax does
+not place any restriction on what character may be escaped, e.g., <code>\\[\n\r\f0-9a-f]</code> are
+permitted. If one of these latter escapes appears in a &lt;familyName&gt; expression, then it will
+need to be converted to a <code>{unicode}</code> escape if it is to be used with a standard XSL-FO
+or CSS parser. In particular, a backslash followed by a newline is ignored by CSS, while it is not
+ignored by the above syntax. Such an unignored escaped newline would need to be represented using
+an equivalent <code>{unicode}</code> escape, such as <code>\a</code>, to order to express in CSS.</p></div></div><div class="div3">
+<h4><a id="style-value-genericFamilyName"></a>10.3.11 &lt;genericFamilyName&gt;</h4><p>A &lt;genericFamilyName&gt; expression specifies a font family using a general
+token that indicates a class of font families.</p><p>The resolution of a generic family name to a concrete font instance is considered to
+be implementation dependent, both in the case of content authoring and content interpretation.</p><a id="genericFamilyName-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;genericFamilyName&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;genericFamilyName&gt;
+  : "default"
+  | "monospace"
+  | "sansSerif"
+  | "serif"
+  | "monospaceSansSerif"
+  | "monospaceSerif"
+  | "proportionalSansSerif"
+  | "proportionalSerif"
+</pre></div>
+</td></tr></tbody></table><p>The mapping between a generic (font) family name and an actual font is not
+determined by this specification; however, the
+distinction of monospace versus proportional and serif versus sans-serif
+should be maintained if possible when performing presentation.</p><p>If a generic (font) family name of <code>monospace</code> is specified,
+then it may be interpreted as equivalent to either <code>monospaceSansSerif</code>
+or <code>monospaceSerif</code>. The generic family names <code>sansSerif</code>
+and <code>serif</code> are to be interpreted as equivalent to <code>proportionalSansSerif</code>
+and <code>proportionalSerif</code>, respectively.</p><p>If the generic family name <code>default</code> is specified (or implied by
+an initial value), then its typographic characteristics are considered to be implementation
+dependent; however, it is recommended that this default font family be mapped to
+an monospaced, sans-serif font.</p></div><div class="div3">
+<h4><a id="style-value-hexDigit"></a>10.3.12 &lt;hexDigit&gt;</h4><p>A &lt;hexDigit&gt; is used to express integers and other types of numbers or tokens
+that employ base 16 arithmetic.</p><p>For the purpose of parsing, a distinction must not be made between lower and upper case.</p><a id="hexDigit-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;hexDigit&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;hexDigit&gt;
+  : <a href="#style-value-digit">&lt;digit&gt;</a>
+  | "a" | "b" | "c" | "d" | "e" | "f"
+  | "A" | "B" | "C" | "D" | "E" | "F"
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-value-integer"></a>10.3.13 &lt;integer&gt;</h4><p>An &lt;integer&gt; expression is used to express an arbitrary, signed integral value.</p><a id="integer-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;integer&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;integer&gt;
+  : ( "+" | "-" )? <a href="#style-value-non-negative-integer">&lt;non-negative-integer&gt;</a>
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-value-length"></a>10.3.14 &lt;length&gt;</h4><p>A &lt;length&gt; expression is used to express either a coordinate component of point
+in a cartesian space or a distance between two points in a cartesian space.</p><a id="length-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;length&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;length&gt;
+  : scalar
+  | <a href="#style-value-percentage">&lt;percentage&gt;</a>
+
+scalar
+  : <a href="#style-value-percentage">&lt;number&gt;</a> units
+
+units
+  : "px"
+  | "em"
+  | "c"                                     // abbreviation of "cell"
+  | "vw"
+  | "vh"
+</pre></div>
+</td></tr></tbody></table><p>It is an error to omit the units component of a scalar length
+value.</p><p>The semantics of
+the unit of measure <code>px</code> (pixel) 
+are as defined by <a href="#xsl11">[XSL 1.1]</a>, § 5.9.13.</p><div class="issue"><p class="prefix"><a id="issue-179"></a><b>Issue (issue-179):</b></p><p class="prefix"><b>Definition of Pixel</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/179">http://www.w3.org/AudioVideo/TT/tracker/issues/179</a></p><p>Replace unworkable (and unadopted) definition of pixel with an appropriate definition based on units of some viewport coordinate space.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>When specified relative to a font whose size is expressed as a single length
+measure or as two length measures of equal length, the unit of measure <code>em</code> is considered to be
+identical to that defined by <a href="#xsl11">[XSL 1.1]</a>, § 5.9.13;
+however, when specified relative to a font whose size is expressed as
+two length measures of non-equal lengths, then one <code>em</code> is
+equal to the inline progression dimension of the anamorphically
+scaled font when used to specify lengths in the inline progression
+direction and equal to the block progression dimension of the scaled
+font when used to specify lengths in the block progression direction.</p><p>The semantics of the unit of measure <code>c</code> (cell) are
+defined by the parameter <a href="#parameter-attribute-cellResolution"><b>7.2.1 ttp:cellResolution</b></a>.</p><p>The units of measure <code>vw</code> and <code>vh</code> are defined as
+one percent (1%) of the width and height of the <a href="#terms-root-container-region">root container region</a>, respectively.
+For example, the length <code>25vw</code> is interpreted as 25% of the width of
+the <a href="#terms-root-container-region">root container region</a>.</p></div><div class="div3">
+<h4><a id="style-value-measure"></a>10.3.15 &lt;measure&gt;</h4><p>A &lt;measure&gt; value expresses a distance used to measure an allocation
+dimension in either the inline progression direction or the block progression direction, where
+the direction that applies is determined by the context of use.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The terms <em>width</em> and <em>height</em> are interpreted in a writing mode relative manner
+such that <em>width</em> always corresponds to a measure in the inline
+progression direction and <em>height</em> always corresponds to a measure in the block progression direction.
+Therefore, in horizontal writing modes, <em>width</em> expresses a horizontal measure
+and <em>height</em> expresses a vertical measure, while, in vertical writing mode, <em>width</em> expresses a vertical measure
+and <em>height</em> expresses a horizontal measure, where horizontal and vertical are always interpreted in an absolute sense.</p></div><a id="measure-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;measure&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;measure&gt;
+  : auto
+  | available
+  | fitContent
+  | maxContent
+  | minContent
+  | <a href="#style-value-length">&lt;length&gt;</a>
+</pre></div>
+</td></tr></tbody></table><p>The semantics of measure values are defined as follows:</p><dl><dt class="label"><code>auto</code></dt><dd><p>As determined by <a href="#semantics-style-automatic-measure-calculation"><b>10.4.5 Automatic Measure Calculation</b></a>.</p></dd><dt class="label"><code>available</code></dt><dd><p>For width in a horizontal writing mode, the numeric value equal to the width of the parent containing block's width less
+the current element's combined border and padding width.
+For height in a horizontal writing mode, the numeric value equal to the height of the parent containing block's height less
+the current element's combined border and padding height.</p><p>For vertical writing mode, the sense of width and height is reversed.</p></dd><dt class="label"><code>fitContent</code></dt><dd><p>A numeric value equal to the maximum of the values of (1) <code>minContent</code> and (2) the minimum of values of <code>maxContent</code> and <code>available</code>.</p></dd><dt class="label"><code>maxContent</code></dt><dd><p>For width in a horizontal writing mode, the maximum numeric value that encloses all of the element's content such that lines are broken only at
+hard, i.e., mandatory, break points, even if that means overflowing the parent's width.</p><p>For height in a horizontal writing mode, the maximum numeric value that encloses all of the element's content such that lines are broken at
+all possible line break positions, i.e., both hard (mandatory) and soft (optional) break points.</p><p>For vertical writing mode, the sense of width and height is reversed.</p></dd><dt class="label"><code>minContent</code></dt><dd><p>For width in a horizontal writing mode, the minimum numeric value that encloses all of the element's content such that lines are broken at
+all possible line break positions, i.e., both hard (mandatory) and soft (optional) break points.</p><p>For height in a horizontal writing mode, the minimum numeric value that encloses all of the element's content such that lines are broken only at
+hard, i.e., mandatory, break points, even if that means overflowing the parent's width.</p><p>For vertical writing mode, the sense of width and height is reversed.</p></dd><dt class="label"><code><a href="#style-value-length">&lt;length&gt;</a></code></dt><dd><p>A non-negative numeric value expressed as a scalar or percentage.</p></dd></dl></div><div class="div3">
+<h4><a id="style-value-namedColor"></a>10.3.16 &lt;namedColor&gt;</h4><p>A &lt;namedColor&gt; is used to express an RGBA color with a convenient name, and where the applicable color space is
+defined by <a href="#srgb">[SRGB]</a>.</p><p>For the purpose of parsing, a distinction must not be made between lower and upper case.</p><a id="namedColor-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;namedColor&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;namedColor&gt;
+  : "transparent"                           // #00000000
+  | "black"                                 // #000000ff
+  | "silver"                                // #c0c0c0ff
+  | "gray"                                  // #808080ff
+  | "white"                                 // #ffffffff
+  | "maroon"                                // #800000ff
+  | "red"                                   // #ff0000ff
+  | "purple"                                // #800080ff
+  | "fuchsia"                               // #ff00ffff
+  | "magenta"                               // #ff00ffff (= fuchsia)
+  | "green"                                 // #008000ff
+  | "lime"                                  // #00ff00ff
+  | "olive"                                 // #808000ff
+  | "yellow"                                // #ffff00ff
+  | "navy"                                  // #000080ff
+  | "blue"                                  // #0000ffff
+  | "teal"                                  // #008080ff
+  | "aqua"                                  // #00ffffff
+  | "cyan"                                  // #00ffffff (= aqua)
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>Except for <code>transparent</code>, the set of named colors specified above constitutes a proper
+subset of the set of named colors specified by <a href="#svg11">[SVG 1.1]</a>, § 4.2.</p></div></div><div class="div3">
+<h4><a id="style-value-non-negative-integer"></a>10.3.17 &lt;non-negative-integer&gt;</h4><p>A &lt;non-negative-integer&gt; expression is used to express an arbitrary, non-negative integral value.</p><a id="non-negative-integer-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;non-negative-integer&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;non-negative-integer&gt;
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-value-number"></a>10.3.18 &lt;number&gt;</h4><p>An &lt;number&gt; expression is used to express an arbitrary, signed integer or real valued number.</p><a id="number-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;number&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;number&gt;
+  : sign? non-negative-number
+
+sign
+  : "+" | "-"
+
+number
+
+non-negative-number
+  : <a href="#style-value-non-negative-integer">&lt;non-negative-integer&gt;</a>
+  | non-negative-real
+
+non-negative-real
+  : <a href="#style-value-digit">&lt;digit&gt;</a>* "." <a href="#style-value-digit">&lt;digit&gt;</a>+
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-value-percentage"></a>10.3.19 &lt;percentage&gt;</h4><p>An &lt;percentage&gt; expression is used to express an arbitrary, signed integral or real valued percentage.</p><a id="percentage-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;percentage&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;percentage&gt;
+  : <a href="#style-value-number">&lt;number&gt;</a> "%"
+</pre></div>
+</td></tr></tbody></table></div><div class="div3">
+<h4><a id="style-value-position"></a>10.3.20 &lt;position&gt;</h4><p>A &lt;position&gt; expression is used to indirectly determine the origin of an area or an image with respect to a reference area.</p><a id="position-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;position&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;position&gt;
+  : offset-position-h                       // single component value
+  | offset-position-v                       // single component value
+  | offset-position-h offset-position-v     // two component values
+  | position-keyword-h edge-offset-v        // three component values
+  | position-keyword-v edge-offset-h        // three component values
+  | edge-offset-h position-keyword-v        // three component values
+  | edge-offset-v position-keyword-h        // three component values
+  | edge-offset-h edge-offset-v             // four component values
+  | edge-offset-v edge-offset-h             // four component values
+
+offset-position-h
+  : position-keyword-h
+  | <a href="#style-value-length">&lt;length&gt;</a>
+
+offset-position-v
+  : position-keyword-v
+  | <a href="#style-value-length">&lt;length&gt;</a>
+
+edge-offset-h
+  : edge-keyword-h <a href="#style-value-length">&lt;length&gt;</a>
+
+edge-offset-v
+  : edge-keyword-v <a href="#style-value-length">&lt;length&gt;</a>
+
+position-keyword-h
+  : center
+  | edge-keyword-h
+
+position-keyword-v
+  : center
+  | edge-keyword-v
+
+edge-keyword-h
+  : left
+  | right
+
+edge-keyword-v
+  : top
+  | bottom
+</pre></div>
+</td></tr></tbody></table><p>A &lt;position&gt; expression may consist of one to four component values as follows:</p><dl><dt class="label">one component</dt><dd><p>either a horizontal offset (<code>offset-position-h</code>) or a vertical offset (<code>offset-position-v</code>)</p></dd><dt class="label">two components</dt><dd><p>a horizontal offset (<code>offset-position-h</code>) followed by a vertical offset (<code>offset-position-v</code>)</p></dd><dt class="label">three components</dt><dd><p>a horizontal edge offset (<code>edge-offset-position-h</code>) and a vertical edge offset (<code>edge-offset-position-v</code>), in any order, where one offset is a keyword and the other offset is a keyword <a href="#style-value-length">&lt;length&gt;</a> pair</p></dd><dt class="label">four components</dt><dd><p>a horizontal edge offset (<code>edge-offset-position-h</code>) and a vertical edge offset (<code>edge-offset-position-v</code>), in any order, where both offsets are keyword <a href="#style-value-length">&lt;length&gt;</a> pairs</p></dd></dl><p>Every &lt;position&gt; expression can be translated to a four component equivalent of the form
+<code>left <a href="#style-value-length">&lt;length&gt;</a> top <a href="#style-value-length">&lt;length&gt;</a></code> by means of the following
+equivalence tables:</p><a id="position-expression-one-component-equivalents"></a><table class="common"><caption>One Component Equivalents</caption><col width="25%" span="1"><col width="25%" span="1"><tbody><tr><th>Value</th><th>Equivalent</th></tr><tr><td><code>center</code></td><td><code>center center</code></td></tr><tr><td><code>left</code></td><td><code>left center</code></td></tr><tr><td><code>right</code></td><td><code>right center</code></td></tr><tr><td><code>top</code></td><td><code>center top</code></td></tr><tr><td><code>bottom</code></td><td><code>center bottom</code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a></code></td><td><code><a href="#style-value-length">&lt;length&gt;</a> center</code></td></tr></tbody></table><p></p><a id="position-expression-two-component-equivalents"></a><table class="common"><caption>Two Component Equivalents</caption><col width="25%" span="1"><col width="25%" span="1"><tbody><tr><th>Value</th><th>Equivalent</th></tr><tr><td><code>center center</code></td><td><code>left 50% top 50%</code></td></tr><tr><td><code>center top</code></td><td><code>left 50% top 0%</code></td></tr><tr><td><code>center bottom</code></td><td><code>left 50% top 100%</code></td></tr><tr><td><code>center <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 50% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>left center</code></td><td><code>left 0% top 50%</code></td></tr><tr><td><code>left top</code></td><td><code>left 0% top 0%</code></td></tr><tr><td><code>left bottom</code></td><td><code>left 0% top 100%</code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 0% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>right center</code></td><td><code>left 100% top 50%</code></td></tr><tr><td><code>right top</code></td><td><code>left 100% top 0%</code></td></tr><tr><td><code>right bottom</code></td><td><code>left 100% top 100%</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 100% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a> top</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a> bottom</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code><a href="#style-value-length">&lt;length&gt;</a> <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr></tbody></table><p></p><a id="position-expression-three-component-equivalents"></a><table class="common"><caption>Three Component Equivalents</caption><col width="25%" span="1"><col width="25%" span="1"><tbody><tr><th>Value</th><th>Equivalent</th></tr><tr><td><code>bottom left <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code>bottom right <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>left 50% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length&gt;</a> left</code></td><td><code>left 0% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length&gt;</a> right</code></td><td><code>left 100% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>center bottom <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 50% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>center left <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code>center right <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code>center top <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 50% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>left bottom <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 0% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>left top <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 0% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length&gt;</a> bottom</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top</code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code>right bottom <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 100% bottom <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>right top <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left 100% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length&gt;</a> bottom</code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 100%</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 50%</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top</code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code>top left <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code>top right <a href="#style-value-length">&lt;length&gt;</a></code></td><td><code>right <a href="#style-value-length">&lt;length&gt;</a> top 0%</code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length&gt;</a> center</code></td><td><code>left 50% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length&gt;</a> left</code></td><td><code>left 100% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length&gt;</a> right</code></td><td><code>left 100% top <a href="#style-value-length">&lt;length&gt;</a></code></td></tr></tbody></table><p></p><a id="position-expression-four-component-equivalents"></a><table class="common"><caption>Four Component Equivalents</caption><col width="25%" span="1"><col width="25%" span="1"><tbody><tr><th>Value</th><th>Equivalent</th></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length-v&gt;</a> left <a href="#style-value-length">&lt;length-h&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length-h&gt;</a> top (100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code></td></tr><tr><td><code>bottom <a href="#style-value-length">&lt;length-v&gt;</a> right <a href="#style-value-length">&lt;length-h&gt;</a></code></td><td><code>left (100% - <a href="#style-value-length">&lt;length-h&gt;</a>) top (100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code></td></tr><tr><td><code>left <a href="#style-value-length">&lt;length-h&gt;</a> bottom <a href="#style-value-length">&lt;length-v&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length-h&gt;</a> top (100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length-h&gt;</a> bottom <a href="#style-value-length">&lt;length-v&gt;</a></code></td><td><code>left (100% - <a href="#style-value-length">&lt;length-h&gt;</a>) top (100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code></td></tr><tr><td><code>right <a href="#style-value-length">&lt;length-h&gt;</a> top <a href="#style-value-length">&lt;length-v&gt;</a></code></td><td><code>left (100% - <a href="#style-value-length">&lt;length-h&gt;</a>) top <a href="#style-value-length">&lt;length-v&gt;</a></code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length-v&gt;</a> left <a href="#style-value-length">&lt;length-h&gt;</a></code></td><td><code>left <a href="#style-value-length">&lt;length-h&gt;</a> top <a href="#style-value-length">&lt;length-v&gt;</a></code></td></tr><tr><td><code>top <a href="#style-value-length">&lt;length-v&gt;</a> right <a href="#style-value-length">&lt;length-h&gt;</a></code></td><td><code>left (100% - <a href="#style-value-length">&lt;length-h&gt;</a>) top <a href="#style-value-length">&lt;length-v&gt;</a></code></td></tr></tbody></table><p>If a <a href="#style-value-length">&lt;length&gt;</a> component is expressed as a percentage, then that percentage is interpreted in relation to
+some reference dimension, where the reference dimension is defined by the context of use.</p><p>A <a href="#style-value-length">&lt;length&gt;</a> component of a &lt;position&gt; expression may be positive or negative. Positive lengths are interpreted as
+insets from the referenced edge, while negative lengths are interpreted as outsets from the referenced edge. For example, an inset from the <code>left</code>
+edge is located to the right of that edge (if non-zero), while an outset from the <code>left</code> edge is located to the left of that edge (if non-zero). In
+contrast, an inset from the <code>right</code> edge is located to the left of that edge (if non-zero), while an outset from the <code>right</code> edge
+is located to the right of that edge (if non-zero). A similar arrangement holds for <code>top</code> and <code>bottom</code> edges.</p><p>When performing four component equivalent conversion, the expression <code>(100% - <a href="#style-value-length">&lt;length-h&gt;</a>)</code>
+is to be interpreted as the difference between 100% and the percentage equivalent of the <a href="#style-value-length">&lt;length-h&gt;</a>
+expression. Similarly, the expression <code>(100% - <a href="#style-value-length">&lt;length-v&gt;</a>)</code>
+is to be interpreted as the difference between 100% and the percentage equivalent of the <a href="#style-value-length">&lt;length-v&gt;</a> expression.
+In both cases, the resulting difference may be a negative percentage.</p></div><div class="div3">
+<h4><a id="style-value-shadow"></a>10.3.21 &lt;shadow&gt;</h4><p>A &lt;shadow&gt; value expresses a shadow decoration to be applied to a generated area. If
+the generated area is a glyph area, then it applies to the outline of the glyph (not the glyph area bounding box). If the
+generated area is not a glyph area, then it applies to the border rectangle of the area.</p><a id="shadow-style-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;shadow&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;shadow&gt;
+  : inset? &amp;&amp; <a href="#style-value-length">&lt;length&gt;</a>{2,4} &amp;&amp; <a href="#style-value-color">&lt;color&gt;</a>
+</pre></div>
+</td></tr></tbody></table><p>A shadow value expression consists of an optional <code>inset</code> token term,
+two to four <a href="#style-value-length">&lt;length&gt;</a> terms, and
+an optional <a href="#style-value-color">&lt;color&gt;</a> term.</p><p>The first <a href="#style-value-length">&lt;length&gt;</a> term denotes the offset in the inline progression direction of the associated area,
+where positive denotes towards the end edge and negative towards the start edge,
+the second <a href="#style-value-length">&lt;length&gt;</a> term denotes the offset in the block progression direction of the associated area,
+where positive denotes towards the after edge and negative towards the before edge.
+The third <a href="#style-value-length">&lt;length&gt;</a> term, if present, denotes the blur radius, and must be non-negative.
+The fourth <a href="#style-value-length">&lt;length&gt;</a> term, if present, denotes the spread distance, where positive denotes expansion and negative denotes contraction.</p><p>If no <a href="#style-value-color">&lt;color&gt;</a> term is
+present, then the computed value of the <code>tts:color</code> property applies.</p><p>If applied to a glyph area, then an <code>inset</code> token and a spread distance, if either or both are present, are ignored for purpose of presentation processing.</p><table border="1" class="ednote" summary="Editorial note: Shadow Inset"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Shadow Inset</b></td><td align="right" valign="top">2015-01-08</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define semantics of <code>inset</code> term.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>When a <a href="#style-value-length">&lt;length&gt;</a> expressed in
+cells is used in a <code>tts:textShadow</code> value,
+the cell's dimension in the block progression dimension applies.
+For example, if text shadow thickness is specified as 0.1c, the cell resolution
+is 20 by 10, and the extent of the <a href="#terms-root-container-region">root container region</a> is 640 by 480, then the
+shadow thickness will be a nominal 480 / 10 * 0.1 pixels, i.e., 4.8px,
+without taking into account rasterization effects.</p></div></div></div><div class="div2">
+<h3><a id="semantics-styling"></a>10.4 Styling Semantics</h3><p>This section defines the semantics of style resolution in terms of
+a standard processing model as follows:</p><ul><li><p><a href="#semantics-style-association"><b>10.4.1 Style Association</b></a></p></li><li><p><a href="#semantics-style-inheritance"><b>10.4.2 Style Inheritance</b></a></p></li><li><p><a href="#semantics-style-resolution-value-categories"><b>10.4.3 Style Resolution Value Categories</b></a></p></li><li><p><a href="#semantics-style-resolution-processing"><b>10.4.4 Style Resolution Processing</b></a></p></li></ul><p>Any implementation of this model is permitted provided that the
+externally observable results are consistent with the results produced
+by this model.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of style resolution employed here are based upon
+<a href="#xsl11">[XSL 1.1]</a>, § 5.</p></div><div class="div3">
+<h4><a id="semantics-style-association"></a>10.4.1 Style Association</h4><p>Style association is a sub-process of <a href="#semantics-style-resolution-processing"><b>10.4.4 Style Resolution Processing</b></a> used to determine the
+specified style set of each content and
+layout element.</p><p>Style matter may be associated with content
+ and layout matter in a number of ways:</p><ul><li><p><a href="#semantics-style-association-inline">inline styling</a></p></li><li><p><a href="#semantics-style-association-referential">referential styling</a></p></li><li><p><a href="#semantics-style-association-chained-referential">chained referential styling</a></p></li></ul><p>In addition to the above, style matter may be associated with layout matter using:</p><ul><li><p><a href="#semantics-style-association-nested">nested styling</a></p></li></ul><div class="div4">
+<h5><a id="semantics-style-association-inline"></a>10.4.1.1 Inline Styling</h5><p>Style properties may be expressed in an inline manner by direct
+specification of an attribute from the TT Style Namespace on the
+affected element. When expressed in this manner, the association of
+style information is referred to as <em>inline styling</em>.</p><p>Style properties associated by inline styling are afforded a higher priority than all other
+forms of style association.</p><a id="style-association-example-1"></a><table class="example"><caption>Example – Inline Styling</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;p <span class="strong">tts:color="white"</span>&gt;White 1&nbsp;&lt;span <span class="strong">tts:color="yellow"</span>&gt;Yellow&lt;/span&gt;&nbsp;White 2&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the two text fragments <code>"White 1 "</code> and
+<code>" White 2"</code>, which are interpreted as anonymous spans, are not
+associated with a color style property; rather, they inherit their color style
+from their parent <code>p</code> element as described in <a href="#semantics-style-inheritance-content"><b>10.4.2.1 Content Style Inheritance</b></a> below.  </p></div></div><div class="div4">
+<h5><a id="semantics-style-association-referential"></a>10.4.1.2 Referential Styling</h5><p>Style properties may be expressed in an out-of-line manner and referenced by the
+affected element using the <code>style</code> attribute. When expressed in this manner,
+the association of style information is referred to as <em>referential styling</em>.</p><p>If a <code>style</code> attribute specifies multiple references, then those references are
+evaluated in the specified order, and that order applies to resolution of the value of a
+style property in the case that it is specified along multiple reference paths.</p><p>The use of referential styling is restricted to making
+reference to <code>style</code> element descendants of a <code>styling</code>
+element. It is considered an error to reference a <code>style</code>
+element that is a descendant of a <code>layout</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of referential styling encourages the reuse of style specifications while
+sacrificing locality of reference.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>A single <a href="#terms-content-element">content element</a> may be associated with style properties by a hybrid mixture of
+inline and referential styling, in which case inline styling is given priority as described above
+by <a href="#semantics-style-association-inline"><b>10.4.1.1 Inline Styling</b></a>.</p></div><a id="style-association-example-2"></a><table class="example"><caption>Example – Referential Styling</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;style <span class="strong">xml:id="s1"</span> tts:color="white"/&gt;
+&lt;style <span class="strong">xml:id="s2"</span> tts:color="yellow"/&gt;
+...
+&lt;p <span class="strong">style="s1"</span>&gt;White 1&nbsp;&lt;span <span class="strong">style="s2"</span>&gt;Yellow&lt;/span&gt;&nbsp;White 2&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the two text fragments <code>"White 1 "</code> and
+<code>" White 2"</code>, which are interpreted as anonymous spans, are not
+associated with a color style property; rather, they inherit their color style
+from their parent <code>p</code> element as described in <a href="#semantics-style-inheritance-content"><b>10.4.2.1 Content Style Inheritance</b></a> below.</p></div></div><div class="div4">
+<h5><a id="semantics-style-association-chained-referential"></a>10.4.1.3 Chained Referential Styling</h5><p>Style properties may be expressed in an out-of-line manner and may themselves reference
+other out-of-line style properties, thus creating a chain of references starting at the
+affected element. When expressed in this manner, the association of style information
+is referred to as <em>chained referential styling</em>.</p><p>If the same style property is specified in more than one referenced
+style set, then the last referenced style set applies, where the order of application starts from
+the affected element and proceeds to referenced style sets, and, in turn, to subsequent referenced style sets.</p><p>A loop in a sequence of chained style references must be considered an error.</p><p>The use of referential styling is restricted to making
+reference to <code>style</code> element descendants of a <code>styling</code>
+element. It is considered an error to reference a <code>style</code>
+element that is a descendant of a <code>layout</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of chained referential styling encourages the grouping of style specifications
+into general and specific sets, which further aids in style specification reuse.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>A single <a href="#terms-content-element">content element</a> may be associated with style properties by a hybrid mixture of
+inline, referential styling, and chained referential styling, in which case inline styling is
+given priority as described above by <a href="#semantics-style-association-inline"><b>10.4.1.1 Inline Styling</b></a>.</p></div><a id="style-association-example-3"></a><table class="example"><caption>Example – Chained Referential Styling</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;style <span class="strong">xml:id="s1"</span> tts:color="white" tts:fontFamily="monospaceSerif"/&gt;
+&lt;style <span class="strong">xml:id="s2"</span> <span class="strong">style="s1"</span> tts:color="yellow"/&gt;
+...
+&lt;p <span class="strong">style="s1"</span>&gt;White Monospace&lt;/p&gt;
+&lt;p <span class="strong">style="s2"</span>&gt;Yellow Monospace&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table></div><div class="div4">
+<h5><a id="semantics-style-association-nested"></a>10.4.1.4 Nested Styling</h5><p>Style properties may be expressed in a nested manner by direct specification of one or
+more <code>style</code> element children of the affected element.
+When expressed in this manner, the association of style information
+is referred to as <em>nested styling</em>.</p><p>Style properties associated by nested styling are afforded a lower priority than inline
+styling but with higher priority than referential styling.</p><a id="style-association-example-4"></a><table class="example"><caption>Example – Nested Styling</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region xml:id="r1"&gt;
+  <span class="strong">&lt;style tts:extent="128px 66px"/&gt;</span>
+  <span class="strong">&lt;style tts:origin="0px 0px"/&gt;</span>
+  <span class="strong">&lt;style tts:displayAlign="center"/&gt;</span>
+&lt;/region&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In this version of this specification, nested styling applies only
+to the <code>region</code> element.</p></div></div></div><div class="div3">
+<h4><a id="semantics-style-inheritance"></a>10.4.2 Style Inheritance</h4><p>Style inheritance is a sub-process of <a href="#semantics-style-resolution-processing"><b>10.4.4 Style Resolution Processing</b></a> used to determine the
+specified style set of each content and
+layout element.</p><p>Styles are further propagated to content matter
+using:
+</p><ul><li><p><a href="#semantics-style-inheritance-content">content style inheritance</a></p></li><li><p><a href="#semantics-style-inheritance-region">region style inheritance</a></p></li><li><p><a href="#semantics-style-inheritance-root">root style inheritance</a></p></li></ul><p>For the purpose of determining inherited styles, the element hierarchy of
+an intermediate synchronic document form of a <a href="#terms-document-instance">document instance</a> must be used, where
+such intermediate forms are defined by <a href="#semantics-region-layout-step-1"><b>11.3.1.3 Intermediate Synchronic Document Construction</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The intermediate synchronic document form is utilized rather than
+the original form in order to facilitate region inheritance
+processing.</p></div><div class="div4">
+<h5><a id="semantics-style-inheritance-content"></a>10.4.2.1 Content Style Inheritance</h5><p>Style properties are inherited from ancestor <a href="#terms-content-element">content elements</a>
+within an intermediate synchronic document
+if a style property is not associated with a <a href="#terms-content-element">content element</a> (or
+an anonymous span) and the style property is designated as
+inheritable.</p><p>If a style property is determined to require inheritance, then the inherited value must
+be the value of the same named style property in the computed
+style set of the
+element's nearest ancestor element that defines the property
+within the applicable intermediate synchronic document.</p><a id="style-inheritance-example-2"></a><table class="example"><caption>Example – Content Style Inheritance</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;p <span class="strong">tts:fontFamily="monospaceSansSerif"</span>&gt;
+  &lt;span tts:color="yellow"&gt;Yellow Monospace&lt;/span&gt;
+&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the <code>span</code> element that encloses the character items
+<code>Yellow Monospace</code> is not associated with a <code>tts:fontFamily</code> style
+property and this property is inheritable; therefore, the value of the
+<code>tts:fontFamily</code> style
+is inherited from the computed style
+set of the ancestor <code>p</code> element,
+and is added to the
+specified
+style
+set of the <code>span</code> element.</p></div></div><div class="div4">
+<h5><a id="semantics-style-inheritance-region"></a>10.4.2.2 Region Style Inheritance</h5><p>Style properties are inherited from a <a href="#layout-vocabulary-region">region</a> element in the following case:</p><ol class="enumar"><li><p>if an inheritable style property <em>P</em> is not associated with
+a <a href="#terms-content-element">content element</a>
+or an anonymous span <em>E</em>, and</p></li><li><p>if that style property <em>P</em> is in the computed style
+set of region <em>R</em>, and</p></li><li><p>if that element <em>E</em> is flowed into (presented within) region
+<em>R</em>.</p></li></ol><a id="style-inheritance-example-3"></a><table class="example"><caption>Example – Region Style Inheritance</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region <span class="strong">xml:id="r1"</span>&gt;
+&nbsp;&nbsp;&lt;style tts:color="yellow"/&gt;
+&nbsp;&nbsp;&lt;style tts:fontFamily="monospaceSerif"/&gt;
+&lt;/region&gt;
+...
+&lt;p <span class="strong">region="r1"</span>&gt;Yellow Monospace&lt;/p&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the anonymous span that encloses the character
+items <code>Yellow Monospace</code> effectively inherits the <code>tts:color</code>
+and <code>tts:fontFamily</code> styles specified on the <code>region</code>
+element into which the <code>p</code> element is flowed (presented).</p></div></div><div class="div4">
+<h5><a id="semantics-style-inheritance-root"></a>10.4.2.3 Root Style Inheritance</h5><p>Style properties are inherited from the root <a href="#document-structure-vocabulary-tt">tt</a> element in the following case:</p><ol class="enumar"><li><p>if an inheritable style property <em>P</em> is not associated with
+a <a href="#layout-vocabular-region"><code>region</code></a> element, and</p></li><li><p>if that
+style property <em>P</em> is in the computed style
+set of the root <a href="#document-structure-vocabulary-tt">tt</a> element.</p></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>Root style inheritance provides a mechanism by means of which <code>region</code> elements
+can inherit a common style rather than repeating the specification of the style on each
+<code>region</code> element.</p></div><a id="style-inheritance-example-4"></a><table class="example"><caption>Example – Root Style Inheritance</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt <span class="strong">tts:color="yellow"</span>&gt;
+...
+&lt;region xml:id="r1" <span class="strong">tts:fontFamily="monospaceSerif"</span>/&gt;
+...
+&lt;p region="r1"&gt;Yellow Monospace&lt;/p&gt;
+...
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the <code>region</code> element inherits the
+<code>tts:color</code> style specified on the <code>tt</code> element, which,
+along with the <code>tts:fontFamily</code> style specified on the <code>region</code>
+element, are inherited by <code>p</code> element when selected into the region.</p></div></div></div><div class="div3">
+<h4><a id="semantics-style-resolution-value-categories"></a>10.4.3 Style Resolution Value Categories</h4><p>During style resolution, layout, and presentation processing,
+three categories of style property values are distinguished as
+follows:</p><ul><li><p><a href="#semantics-style-resolved-value-category-specified">specified values</a></p></li><li><p><a href="#semantics-style-resolved-value-category-computed">computed values</a></p></li><li><p><a href="#semantics-style-resolved-value-category-actual">actual values</a></p></li></ul><div class="div4">
+<h5><a id="semantics-style-resolved-value-category-specified"></a>10.4.3.1 Specified Values</h5><p>Values of style properties that are associated with or inherited
+by an element or anonymous span are referred to as <em>specified values</em>. The
+set of all specified style properties of a given element is referred to
+as the <em>specified style set</em> of that element.</p></div><div class="div4">
+<h5><a id="semantics-style-resolved-value-category-computed"></a>10.4.3.2 Computed Values</h5><p>When style properties are specified using relative value expressions,
+such as a named color, a relative unit (e.g., cell), or a percentage, then
+they need to be further resolved into absolute units, such as an RGB triple,
+pixels, etc.</p><p>During the style resolution process, all specified style values are
+reinterpreted (or recalculated) in absolute terms, and then recorded as
+<em>computed values</em>. The
+set of all computed style properties of a given element is referred to
+as the <em>computed style set</em> of that element.</p><p>When a style value is inherited, either explicitly or implicitly, it
+is the computed value of the style that is inherited from an ancestor
+element. This is required since the resolution of certain relative units,
+such as percentage, require evaluating the expression in the immediate
+(local) context of reference, and not in a distant (remote) context of
+reference where the related (resolving) expression is not available.</p></div><div class="div4">
+<h5><a id="semantics-style-resolved-value-category-actual"></a>10.4.3.3 Actual Values</h5><p>During the actual presentation process, other transformations occur
+that map some value expressions to concrete, physical values. For example,
+the colors of computed style values are further subjected to closest color
+approximation and gamma correction
+during the display process. In addition, length value expressions that use
+pixels in computed style values are considered to express logical rather than
+physical (device) pixels. Consequently, these logical pixels are subject to
+being further transformed or mapped to physical (device) pixels during
+presentation.</p><p>The final values that result from the logical to device mapping
+process are referred to as <em>actual values</em>.  The set of all
+actual style properties of a given element is referred to as the
+<em>actual style set</em> of that element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>More than one set of actual values may be produced during the
+process of presentation. For example, a TTML <a href="#terms-presentation-processor">presentation processor</a>
+device may output an RGBA component video signal which is then
+further transformed by an NTSC or PAL television to produce a final
+image. In this case, both color and dimensions may further be modified
+prior to presentation.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>In general, a TTML <a href="#terms-presentation-processor">presentation processor</a> will not have access
+to actual style set values; as a consequence, no further use or reference
+to actual values is made below when formally describing the style
+resolution process.</p></div></div></div><div class="div3">
+<h4><a id="semantics-style-resolution-processing"></a>10.4.4 Style Resolution Processing</h4><p>The process of style resolution is defined herein as the procedure
+(and results thereof) for resolving (determining) the computed values
+of all style properties that apply to content and layout elements:</p><ul><li><p><a href="#semantics-style-resolution-processing-definitions"><b>10.4.4.1 Conceptual Definitions</b></a></p></li><li><p><a href="#semantics-style-resolution-processing-sss"><b>10.4.4.2 Specified Style Set Processing</b></a></p></li><li><p><a href="#semantics-style-resolution-processing-css"><b>10.4.4.3 Computed Style Set Processing</b></a></p></li><li><p><a href="#semantics-style-resolution-process-overall"><b>10.4.4.4 Style Resolution Process</b></a></p></li></ul><p>The process described here forms an integral sub-process of
+<a href="#semantics-region-layout"><b>11.3.1 Region Layout and Presentation</b></a>.</p><div class="div4">
+<h5><a id="semantics-style-resolution-processing-definitions"></a>10.4.4.1 Conceptual Definitions</h5><p>For the purpose of interpreting the style resolution processing
+model specified below, the following conceptual definitions apply:</p><dl><dt class="label">[style property]</dt><dd><p>a style property, <em>P</em>, is considered to consist of a
+tuple <code>[name, value]</code>, where the name of the
+property is a tuple <code>[namespace value,
+unqualified name]</code> and the value of the property is a
+tuple <code>[category, type, value expression]</code></p><a id="conceptual-definition-example-style-property"></a><table class="example"><caption>Example – conceptual style property</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+[
+  ["http://www.w3.org/ns/ttml#styling", "color"],
+  ["specified", <em>color</em>, "red"]
+]
+</pre></div>
+</td></tr></tbody></table><p></p></dd><dt class="label">[style (property) set]</dt><dd><p>a style (property) set consists of an unordered collection of style
+properties, where no two style properties within the set have an
+identical name, where by "identical name" is meant equality of
+namespace value of name tuple and unqualified name of name tuple;</p><p>in a specified style (property) set, the category of each style
+property is "specified"; a specified style (property) set of an
+element <em>E</em> is referred to as <em>SSS(E)</em>;</p><a id="conceptual-definition-example-specified-style-set"></a><table class="example"><caption>Example – conceptual (specified) style (property) set</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+{
+  [
+    ["http://www.w3.org/ns/ttml#styling", "backgroundColor"],
+    ["specified", <em>color</em>, 0x00FF00 ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "color"],
+    ["specified", <em>color</em>, "red" ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "fontSize"],
+    ["specified", <em>length</em>, "1c" ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "lineHeight"],
+    ["specified", <em>length</em>, "117%" ]
+  ]
+}
+</pre></div>
+</td></tr></tbody></table><p>in a computed style (property) set, the category of each style
+property is either "specified" or "computed"; a computed style (property) set of an element
+<em>E</em> is referred to as <em>CSS(E)</em>;</p><a id="conceptual-definition-example-computed-style-set"></a><table class="example"><caption>Example – conceptual (computed) style (property) set</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+{
+  [
+    ["http://www.w3.org/ns/ttml#styling", "backgroundColor"],
+    ["specified", <em>color</em>, 0x00FF00 ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "color"],
+    ["computed", <em>color</em>, 0xFF0000 ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "fontSize"],
+    ["computed", <em>length</em>, "24px" ]
+  ],
+  [
+    ["http://www.w3.org/ns/ttml#styling", "lineHeight"],
+    ["computed", <em>length</em>, "28px" ]
+  ]
+}
+</pre></div>
+</td></tr></tbody></table><p></p></dd><dt class="label">[style (property) merging]</dt><dd><p>a style property <em>P<sub>new</sub></em> is merged into a
+style (property) set, <em>SS</em>, as follows: if a style property
+<em>P<sub>old</sub></em> is already present in <em>SS</em>
+where the name of <em>P<sub>new</sub></em> is identical to the
+name of <em>P<sub>old</sub></em>, then replace
+<em>P<sub>old</sub></em> in <em>SS</em> with
+<em>P<sub>new</sub></em>; otherwise, add
+<em>P<sub>new</sub></em> to <em>SS</em>;</p></dd><dt class="label">[style (property) set merging]</dt><dd><p>a style (property) set <em>SS<sub>new</sub></em> is merged into
+an existing style (property) set <em>SS<sub>old</sub></em> as
+follows: for each style property <em>P<sub>new</sub></em> in
+<em>SS<sub>new</sub></em>, merge <em>P<sub>new</sub></em> into
+<em>SS<sub>old</sub></em>;</p></dd></dl></div><div class="div4">
+<h5><a id="semantics-style-resolution-processing-sss"></a>10.4.4.2 Specified Style Set Processing</h5><p>The specified style set <em>SSS</em> of an element or
+anonymous span <em>E</em>,
+<em>SSS(E)</em>, is determined according to the following ordered
+rules:</p><ol class="enumar"><li><p><span class="strong">[initialization]</span> initialize
+the specified style set <em>SSS</em> of <em>E</em> to the
+empty set;</p></li><li><p><span class="strong">[referential and chained referential
+styling]</span> for each <code>style</code> element <em>S<sub>REF</sub></em>
+referenced by a <code>style</code> attribute specified on
+<em>E</em>, and in the order specified in the <code>style</code>
+attribute, then, if <em>S<sub>REF</sub></em> is a descendant
+of a <code>styling</code> element,
+merge the specified style set of
+<em>S<sub>REF</sub></em>, <em>SSS(S<sub>REF</sub>)</em>, into
+the specified style set of <em>E</em>,
+<em>SSS(E)</em>;</p></li><li><p><span class="strong">[nested styling]</span> for each
+nested <code>style</code> element child <em>S<sub>NEST</sub></em> of
+<em>E</em>, and in the specified order of child elements, merge
+the specified style set of <em>S<sub>NEST</sub></em>,
+<em>SSS(S<sub>NEST</sub>)</em>, into the specified style set of
+<em>E</em>, <em>SSS(E)</em>;</p></li><li><p><span class="strong">[inline styling]</span> for each
+style property <em>P</em> expressed as a specified styling
+attribute of <em>E</em>,
+merge <em>P</em> into the specified style
+set of <em>E</em>, <em>SSS(E)</em>;</p></li><li><p><span class="strong">[animation styling]</span> if the
+element type of <em>E</em> is not the animation element type
+<code>set</code>, then for each
+immediate animation (<code>set</code>) element child <em>A</em> of element <em>E</em>,
+merge the specified style set of <em>A</em>,
+<em>SSS(A)</em>, into the specified style set of <em>E</em>, <em>SSS(E)</em>;</p></li><li><p><span class="strong">[implicit inheritance and initial value fallback]</span> if the
+element type of <em>E</em> is not animation element type <code>animate</code> or <code>set</code>
+and is not styling element type <code>style</code>,
+then for each style property
+<em>P</em> in the set of style properties defined
+above in <a href="#styling-attribute-vocabulary"><b>10.2 Styling Attribute Vocabulary</b></a>, perform the
+following ordered sub-steps:</p><ol class="enumla"><li><p>if <em>P</em> is present in the specified
+style set of <em>E</em>, <em>SSS(E)</em>, then continue to the
+next style property;</p></li><li><p>if <em>P</em> is defined to be inheritable and <em>E</em> is
+not the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element, then perform the following:</p><ul><li><p>set <em>P′</em> to the result of
+looking up the value of <em>P</em> in the computed style set of
+the nearest ancestor element of <em>E</em>, <em>NEAREST-ANCESTOR(E)</em>, such that
+<em>CSS(NEAREST-ANCESTOR(E))</em> contains a definition of <em>P</em>;</p></li></ul></li><li><p>otherwise (<em>P</em> is not inheritable or <em>E</em> is
+the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element), perform the following:</p><ul><li><p>set <em>P′</em> to the initial value of
+property <em>P</em>, where the initial value of a property is
+determined as follows:</p><ol class="enumlr"><li><p>if an <a href="#styling-vocabulary-initial"><code>initial</code></a>
+element defines the initial value for <em>P</em>, then use that value;</p></li><li><p>otherwise, use the initial value specified by the property definition of <em>P</em> found above
+in <a href="#styling-attribute-vocabulary"><b>10.2 Styling Attribute Vocabulary</b></a>;</p></li></ol></li></ul></li><li><p>if the value of <em>P′</em> is not undefined, then merge
+<em>P′</em> into the specified style set of <em>E</em>,
+<em>SSS(E)</em>.</p></li></ol></li></ol></div><div class="div4">
+<h5><a id="semantics-style-resolution-processing-css"></a>10.4.4.3 Computed Style Set Processing</h5><p>The computed style set <em>CSS</em> of an element or
+anonymous span <em>E</em>,
+<em>CSS(E)</em>, is determined according to the following ordered
+rules:</p><ol class="enumar"><li><p><span class="strong">[resolve specified styles]</span>
+determine (obtain) the specified style set <em>SSS</em> of
+<em>E</em>, namely, <em>SSS(E)</em>, in accordance with
+<a href="#semantics-style-resolution-processing-sss"><b>10.4.4.2 Specified Style Set Processing</b></a>;</p></li><li><p><span class="strong">[initialization]</span>
+initialize <em>CSS(E)</em> to a (deep) copy of
+<em>SSS(E)</em>;</p></li><li><p><span class="strong">[filter]</span> if
+<em>E</em> is an <code>animate</code>, <code>set</code>, or <code>style</code> element, then return
+<em>CSS(E)</em> as the resulting computed style set without
+further resolution; otherwise, continue with the next rule;</p></li><li><p><span class="strong">[relative value resolution]</span> for each
+style property <em>P</em> in <em>CSS(E)</em>, where the value
+type of <em>P</em> is relative, perform the following ordered
+sub-steps:</p><ol class="enumla"><li><p>replace the relative value of <em>P</em> with an
+equivalent, non-relative (computed) value;</p></li><li><p>set the category of <em>P</em> to "computed";</p></li></ol></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>As a result of the filtering rule above, the computed style set of
+an <code>animate</code>, <code>set</code>, or <code>style</code> element includes only specified values, in which case
+relative value expressions remain relative; consequently, the
+resolution of relative value expressions (that may be assigned by
+means of referential style association) always takes place in the
+context of a layout or <a href="#terms-content-element">content element</a> which has a presentation
+context, and not in the non-presentation, declaration context
+of an <code>animate</code>, <code>set</code>, or referable <code>style</code> element.</p></div></div><div class="div4">
+<h5><a id="semantics-style-resolution-process-overall"></a>10.4.4.4 Style Resolution Process</h5><p>The top-level style resolution process is defined as follows: using
+a preorder traversal of each element and <em>anonymous span</em>,
+<em>E</em>, of an intermediate synchronic document,
+<em>DOC<sub>inter</sub></em>, perform the following ordered
+sub-steps:</p><ol class="enumar"><li><p><span class="strong">[filter]</span> if <em>E</em>
+is not one of the following, then continue to the next element in the preorder traversal, i.e.,
+do not perform the subsequent step below on <em>E</em>:</p><ul><li><p><a href="#document-structure-vocabulary-tt"><code>tt</code></a></p></li><li><p><a href="#styling-vocabulary-style"><code>style</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li><li><p><a href="#animation-vocabulary-animate"><code>animate</code></a></p></li><li><p><a href="#animation-vocabulary-set"><code>set</code></a></p></li><li><p><em>anonymous span</em></p></li></ul></li><li><p> <span class="strong">[resolve computed styles]</span>
+determine (obtain) the computed style set <em>CSS</em> of
+<em>E</em>, namely, <em>CSS(E)</em>, in accordance with
+<a href="#semantics-style-resolution-processing-css"><b>10.4.4.3 Computed Style Set Processing</b></a>.</p></li></ol></div></div><div class="div3">
+<h4><a id="semantics-style-automatic-measure-calculation"></a>10.4.5 Automatic Measure Calculation</h4><table border="1" class="ednote" summary="Editorial note: Automatic Measures"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Automatic Measures</b></td><td align="right" valign="top">2014-11-30</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define semantics for resolving the <code>auto</code> value as used with a  <a href="#style-value-measure">&lt;measure&gt;</a> expression,
+the definition of which should be consistent with <a href="#css3-box">[CSS Box Model]</a>, § 15.</td></tr></table></div></div></div><div class="div1">
+<h2><a id="layout"></a>11 Layout</h2><p>This section specifies the <em>layout</em> matter of the core
+vocabulary catalog, where
+layout is to be understood as a separable layer of information that applies to
+content and that denotes authorial intentions about the presentation of
+that content.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The two layers of layout and style matter are considered to be independently
+separable. Layout matter specifies one or more spaces or areas into
+which content is intended to be presented, while style matter specifies the manner in
+which presentation occurs within the layout.</p><p>In certain cases, a content author may choose to embed (inline) style matter directly
+into layout or content matter. In such cases, an alternative 
+exists – use of referential styling –
+in which the style
+matter is not embedded (inlined).</p></div><div class="div2">
+<h3><a id="layout-element-vocabulary"></a>11.1 Layout Element Vocabulary</h3><p>The following elements specify the structure and principal layout aspects of a
+<a href="#terms-document-instance">document instance</a>:</p><ul><li><p><a href="#layout-vocabulary-layout"><b>11.1.1 layout</b></a></p></li><li><p><a href="#layout-vocabulary-region"><b>11.1.2 region</b></a></p></li></ul><div class="div3">
+<h4><a id="layout-vocabulary-layout"></a>11.1.1 layout</h4><p>The <code>layout</code> element is a container element used to group
+out-of-line layout matter, including metadata that applies to layout matter.</p><p>The <code>layout</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by
+zero or more <code>region</code> elements.</p><a id="elt-syntax-layout"></a><table class="syntax"><caption>XML Representation – Element Information Item: layout</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;layout
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#layout-vocabulary-region">region</a>*
+&lt;/layout&gt;
+</pre></div>
+</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
+<code>layout</code> element, the implied time interval of this element is
+defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div><div class="div3">
+<h4><a id="layout-vocabulary-region"></a>11.1.2 region</h4><p>The <code>region</code> element is used to define a rectangular space or area into which content is
+to be flowed for the purpose of presentation.</p><p>A <code>region</code> element may appear as either (1) a child of a
+<a href="#layout-vocabulary-layout">layout</a> element or (2) a child of block level
+<a href="#terms-content-element">content element</a>, specifically, of elements
+in the <a href="#element-vocab-group-block">Block.class</a> element group.
+In the former case, the region is referred to as an <a href="#terms-out-of-line-region">out-of-line region</a>, while in the latter
+case, it is referred to as an <a href="#terms-inline-region">inline region</a>.</p><p>In addition, and in accordance with
+<a href="#semantics-style-inheritance-region"><b>10.4.2.2 Region Style Inheritance</b></a>, 
+the <code>region</code> element may be used to specify inheritable style properties to be
+inherited by content that is flowed into it.</p><p>The <code>region</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more
+elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group,
+followed by
+zero or more <code>style</code> elements.</p><p>Any metadata specified by children in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a>
+element group applies semantically to the <code>region</code> element and its descendants as a whole.
+Any animation elements specified by children in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a>
+element group apply semantically to the <code>region</code> element.
+Any <code>style</code> child element must be considered a local style
+definition that applies only to the containing <code>region</code>
+element, i.e., does not apply for resolving referential styling (but does apply for region
+style inheritance).</p><a id="elt-syntax-region"></a><table class="syntax"><caption>XML Representation – Element Information Item: region</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;region
+  <a href="#animation-attribute-animate">animate</a> = IDREFS
+  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#timing-attribute-timeContainer">timeContainer</a> = (<em>par</em>|<em>seq</em>)
+  <a href="#metadata-attribute-role">ttm:role</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*, <a href="#styling-vocabulary-style">style</a>*
+&lt;/region&gt;
+</pre></div>
+</td></tr></tbody></table><p>An <a href="#terms-out-of-line-region">out-of-line</a> <code>region</code> element
+must specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute.</p><p>An <a href="#terms-out-of-line-region">out-of-line</a> <code>region</code> element may specify one or more of the timing attributes:
+<code>begin</code>, <code>end</code>, <code>dur</code>. An <a href="#terms-inline-region">inline</a> <code>region</code> element must not
+specifiy a timing attribute, and, if specified, must be ignored for the purpose
+of presentation processing.</p><p>If <code>begin</code> and (or) <code>end</code> attributes are specified on an out-of-line
+<code>region</code> element, then they specify the beginning and (or) ending points
+of a time interval during which the region is eligible for activation and with
+respect to which animation child elements of the region are timed.
+If specified, these begin and end points are relative to the time
+interval of the nearest ancestor element associated with a time
+interval, irregardless of whether that interval is explicit or implied.
+The nearest ancestor element of an out-of-line <code>region</code> element that is associated
+with a time interval is the <code>layout</code> element.
+If a <code>dur</code> attribute is specified on an out-of-line <code>region</code> element, then it
+specifies the simple duration of the region.</p><p>The active time interval of an <a href="#terms-inline-region">inline</a> <code>region</code> element is the
+active time interval of its parent <a href="#terms-content-element">content element</a>.</p><p>For the purpose of determining the semantics of presentation processing, a
+region that is temporally inactive must not produce any visible marks when
+presented on a visual medium.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>An <a href="#terms-out-of-line-region">out-of-line</a> <code>region</code> element may be associated with a time interval for two
+purposes: (1) in order to temporally bound the presentation of the region and
+its content, and (2) to provide a temporal context in which animations of region
+styles may be effected.</p><p>For example, an author may wish to specify an <a href="#terms-out-of-line-region">out-of-line</a> <code>region</code> element that is otherwise empty, but
+may have a visible background color to be presented starting at some time and
+continuing over the region's duration.  The simple duration of the region serves
+additionally to scope the presentation effects of content that is targeted to the
+region. An author may also wish to move a region within the <a href="#terms-root-container-region">root container region</a>
+or change a region's background color by means of animation effects. In
+both of these cases, it is necessary to posit an active time interval for a
+region.</p><p>In contrast to <a href="#terms-out-of-line-region">out-of-line regions</a>, <a href="#terms-inline-region">inline regions</a> are specifically bound to
+the temporal context of their parent <a href="#terms-content-element">content elements</a>,
+and, as such, do not require (or admit) the specification of independent timing.</p></div><p>If no <code>timeContainer</code> attribute is specified on
+a <code>region</code> element, then it must be interpreted as having
+<em>parallel</em> time containment semantics.</p><p>If both <a href="#style-attribute-origin"><code>tts:origin</code></a> and <a href="#style-attribute-position"><code>tts:position</code></a> attributes are present
+on a <code>region</code> element, then the <a href="#style-attribute-origin"><code>tts:origin</code></a> must be ignored for the purpose of presentation processing.
+If neither <a href="#style-attribute-origin"><code>tts:origin</code></a> nor <a href="#style-attribute-position"><code>tts:position</code></a> attribute is present and
+if the computed value of the the <a href="#parameter-attribute-version"><code>ttp:version</code></a> attribute on the root <code>tt</code> element is two (2) or greater, then
+the semantics of the initial value of the <a href="#style-attribute-position"><code>tts:position</code></a> attribute apply for the purpose of presentation processing; otherwise, the semantics of the initial value of the <a href="#style-attribute-origin"><code>tts:origin</code></a> attribute apply.</p><p>If a <a href="#metadata-attribute-role"><code>ttm:role</code></a> attribute is
+specified on a <code>region</code> element, then it must adhere to the
+value syntax defined by <a href="#metadata-attribute-role-syntax"><b>Syntax Representation – ttm:role</b></a>, and where the roles identified
+by this attribute express the semantic roles of the region
+independently from the semantic roles of any content targeted to
+(associated with) the region.</p></div></div><div class="div2">
+<h3><a id="layout-attribute-vocabulary"></a>11.2 Layout Attribute Vocabulary</h3><p>This section defines the <a href="#layout-attribute-region"><b>11.2.1 region</b></a> attribute used with <a href="#terms-content-element">content elements</a>.</p><div class="div3">
+<h4><a id="layout-attribute-region"></a>11.2.1 region</h4><p>The <code>region</code> attribute is used to reference a <code>region</code>
+element which defines a space or area into which a <a href="#terms-content-element">content element</a> is intended to be flowed.</p><p>If specified, the value of a <code>region</code> attribute must
+adhere to the <code>IDREF</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§ 3.3.9, and, furthermore, this IDREF must reference a <code>region</code> element
+which has a <code>layout</code> element as an ancestor.</p><p>The <code>region</code> attribute may be specified by an instance of the following
+element types:</p><ul><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>See <a href="#semantics-region-layout"><b>11.3.1 Region Layout and Presentation</b></a> below for further information on content
+flow in a region.</p></div></div></div><div class="div2">
+<h3><a id="semantics-layout"></a>11.3 Layout Semantics</h3><div class="issue"><p class="prefix"><a id="issue-365"></a><b>Issue (issue-365):</b></p><p class="prefix"><b>HTML Mapping</b></p><p><b>Source</b>: <a href="https://www.w3.org/AudioVideo/TT/tracker/issues/365">https://www.w3.org/AudioVideo/TT/tracker/issues/365</a></p><p>Define HTML5 mapping while separating ISD generation from follow-on mappings.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><div class="div3">
+<h4><a id="semantics-region-layout"></a>11.3.1 Region Layout and Presentation</h4><p>This section defines the semantics of region layout and
+presentation in terms of a standard processing model as
+follows:</p><ul><li><p><a href="#semantics-default-region"><b>11.3.1.1 Default Region</b></a></p></li><li><p><a href="#semantics-inline-regions"><b>11.3.1.2 Inline Regions</b></a></p></li><li><p><a href="#semantics-region-layout-step-1"><b>11.3.1.3 Intermediate Synchronic Document Construction</b></a></p></li><li><p><a href="#semantics-region-layout-step-2"><b>11.3.1.4 Synchronic Flow Processing</b></a></p></li><li><p><a href="#semantics-region-layout-example"><b>11.3.1.5 Elaborated Example (Non-Normative)</b></a></p></li></ul><p>Any
+implementation is permitted provided that the externally observable
+results are consistent with the results produced by this model.
+</p><div class="div4">
+<h5><a id="semantics-default-region"></a>11.3.1.1 Default Region</h5><p>If a <a href="#terms-document-instance">document instance</a> does not specify an
+<a href="#terms-out-of-line-region">out-of-line region</a>,
+then a <em>default region</em> is implied with the following characteristics:</p><ul><li><p>the identity of the default region is considered to be an anonymous <a href="#terms-out-of-line-region">out-of-line region</a>;</p></li><li><p>the extent of the default region is the same as the extent of the <a href="#terms-root-container-region">root container region</a>;</p></li><li><p>the temporal interval of the default region is the same as the interval defined by the <a href="#terms-root-temporal-extent">root temporal extent</a>;</p></li></ul><p>Furthermore, if no
+<a href="#terms-out-of-line-region">out-of-line region</a> is specified, then the
+<a href="#layout-attribute-region"><code>region</code></a> attribute must
+not be specified on any <a href="#terms-content-element">content element</a> in the <a href="#terms-document-instance">document instance</a>.</p><p>If a default region is implied for a given <a href="#terms-document-instance">document instance</a>, then
+the <a href="#document-structure-vocabulary-body"><code>body</code></a> element
+is implicitly targeted to (associated with) the default region.</p><p>When implying a default region, the <a href="#terms-document-instance">document instance</a> is to be
+treated as if a <a href="#layout-vocabulary-region"><code>region</code></a> element and its
+parent <a href="#layout-vocabulary-layout"><code>layout</code></a>
+element were specified in a <a href="#document-structure-vocabulary-head"><code>head</code></a>
+element, and a matching <a href="#layout-attribute-region"><code>region</code></a> attribute were
+specified on the <a href="#document-structure-vocabulary-body"><code>body</code></a> element
+as shown in the following example:</p><a id="semantics-default-region-example"></a><table class="example"><caption>Example – Implied Default Region</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head&gt;
+    <span class="strong">&lt;layout&gt;
+      &lt;region xml:id="anonymous"/&gt;
+    &lt;/layout&gt;</span>
+  &lt;/head&gt;
+  &lt;body <span class="strong">region="anonymous"</span>/&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, a default <code>region</code> element and <code>region</code>
+attribute are implied. In addition, a <code>layout</code> container element is implied for
+the implied <code>region</code> element.</p></div></div><div class="div4">
+<h5><a id="semantics-inline-regions"></a>11.3.1.2 Inline Regions</h5><p>An <a href="#terms-inline-region">inline region</a> is a syntactic mechanism for specifying a
+<a href="#terms-region">region</a> in a way that minimizes the syntactic distance between a region
+specification and the content that references that region. Semantically, each
+<a href="#terms-inline-region">inline region</a> is equivalent to specifying a unique
+<a href="#terms-out-of-line-region">out-of-line region</a> referenced implicitly only by the
+<a href="#terms-content-element">content element</a> in whose context the
+<a href="#terms-inline-region">inline region</a> is specified (or implied).</p><p>An <a href="#terms-inline-region">inline region</a> is declared in one of two ways:
+(1) by specifying a <a href="#style-attribute-extent"><code>tts:extent</code></a> or
+<a href="#style-attribute-origin"><code>tts:origin</code></a> style attribute on
+a <a href="#terms-content-element">content element</a>
+in the <a href="#element-vocab-group-block">Block.class</a> element group, or
+(2) by specifying an explicit  <a href="#layout-vocabulary-region"><code>region</code></a> element
+child of a <a href="#terms-content-element">content element</a>
+in the <a href="#element-vocab-group-block">Block.class</a> element group. The
+former is referred to as an <em>implied inline region specification</em>,
+the latter as an <em>explicit inline region specification</em>; furthermore, the former is considered
+to be a syntactic shorthand for the latter, and is processed by converting it into the latter as
+described below.</p><p>Inline regions are processed in accordance with the procedure
+<span class="strong"><a href="#procedure-process-inline-regions">[process inline regions]</a></span>, which
+entails first generating implied inline regions, and then generating out-of-line regions that correspond with implied
+or explicit inline regions. This latter procedure additionally binds content elements associated with inline regions
+to the corresponding generated out-of-line regions.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <a href="#terms-content-element">content element</a> can only be associated with a single
+<a href="#terms-region">region</a>. Consequently, if a <a href="#terms-content-element">content element</a>
+specifies a <a href="#layout-attribute-region"><code>region</code></a> attribute, then any <em>implied inline region specification</em>
+or <em>explicit inline region specification</em> is ignored. If the <a href="#terms-content-element">content element</a> does not specify a
+<a href="#layout-attribute-region"><code>region</code></a> attribute, but it includes
+both an <em>implied inline region specification</em> and an <em>explicit inline region specification</em>,
+then the former is ignored in favor of the latter.</p></div><dl><dt class="label"><a id="procedure-process-inline-regions"></a>[process inline regions]</dt><dd><ol class="enumar"><li><p>perform procedure <span class="strong"><a href="#procedure-generate-inline-regions">[generate inline regions]</a></span>;</p></li><li><p>perform procedure <span class="strong"><a href="#procedure-generate-out-of-line-regions">[generate out-of-line regions]</a></span>;</p></li></ol></dd><dt class="label"><a id="procedure-generate-inline-regions"></a>[generate inline regions]</dt><dd><p>For each <a href="#terms-content-element">content element</a> <em>B</em>
+in the <a href="#element-vocab-group-block">Block.class</a> element group,
+perform the following ordered steps:</p><ol class="enumar"><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains
+neither <a href="#style-attribute-extent"><code>tts:extent</code></a> nor
+<a href="#style-attribute-origin"><code>tts:origin</code></a> style attribute, then exit this procedure;</p></li><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains a
+<a href="#layout-attribute-region"><code>region</code></a> attribute, then exit this procedure</p></li><li><p>if the <code>[children]</code> information item property of <em>B</em> contains a
+<a href="#layout-vocabulary-region"><code>region</code></a> element, then exit this procedure;</p></li><li><p>create an empty <a href="#layout-vocabulary-region"><code>region</code></a> element <em>R</em>,
+initialized as follows:</p><ul><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains a
+<a href="#style-attribute-extent"><code>tts:extent</code></a> attribute,
+then copy that attribute to the <code>[attributes]</code> information item property of <em>R</em>;
+otherwise, add a <a href="#style-attribute-extent"><code>tts:extent</code></a> attribute with value <code>auto</code>
+to the <code>[attributes]</code> information item property of <em>R</em>;</p></li><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains a
+<a href="#style-attribute-origin"><code>tts:origin</code></a> attribute,
+then copy that attribute to the <code>[attributes]</code> information item property of <em>R</em>;
+otherwise, add a <a href="#style-attribute-origin"><code>tts:origin</code></a> attribute with value <code>auto</code>
+to the <code>[attributes]</code> information item property of <em>R</em>;</p></li></ul></li><li><p>insert <em>R</em> into the <code>[children]</code> information item property of <em>B</em>
+such that <em>R</em> immediately precedes the first <a href="#terms-content-element">content element</a>
+child of <em>B</em>, or, if none is present, then <em>R</em> is the last child element of <em>B</em>;</p></li><li><p>remove the <a href="#style-attribute-extent"><code>tts:extent</code></a> and
+<a href="#style-attribute-origin"><code>tts:origin</code></a> style attributes, if present, from the
+<code>[attributes]</code> information item property of <em>B</em>;</p></li></ol></dd><dt class="label"><a id="procedure-generate-out-of-line-regions"></a>[generate out-of-line regions]</dt><dd><p>For each <a href="#terms-content-element">content element</a> <em>B</em>
+in the <a href="#element-vocab-group-block">Block.class</a> element group,
+perform the following ordered steps:</p><ol class="enumar"><li><p>if the <code>[attributes]</code> information item property of <em>B</em> contains a
+<a href="#layout-attribute-region"><code>region</code></a> attribute, then exit this procedure</p></li><li><p>if the <code>[children]</code> information item property of <em>B</em> does not contain
+a <a href="#layout-vocabulary-region"><code>region</code></a> element <em>R</em>, then exit this procedure;</p></li><li><p>create an empty <a href="#layout-vocabulary-region"><code>region</code></a> element <em>R'&nbsp;</em>,
+initialized as follows:</p><ul><li><p>set the <code>[children]</code> information item property of <em>R'&nbsp;</em> to a deep copy of
+the <code>[children]</code> information item property of <em>R</em>;</p></li><li><p>set the <code>[attributes]</code> information item property of <em>R'&nbsp;</em> to a deep copy of
+the <code>[attributes]</code> information item property of <em>R</em>;</p></li><li><p>if the <code>[attributes]</code> information item property of <em>R'&nbsp;</em> does not include
+an <code>xml:id</code> attribute, then add an implied <code>xml:id</code> attribute with a generated value
+<em>ID</em> that is unique within the scope of the TTML <a href="#terms-document-instance">document instance</a>;
+otherwise, let <em>ID</em> be the value of the <code>xml:id</code> attribute of <em>R'&nbsp;</em>;</p></li><li><p>if present, remove the following attributes from the <code>[attributes]</code> information item property of <em>R'&nbsp;</em>:
+<code>begin</code>,
+<code>dur</code>, and
+<code>end</code>;</p></li><li><p>add a <code>begin</code> attribute to the <code>[attributes]</code> information item property of <em>R'&nbsp;</em> with
+a value equivalent to the computed begin time of <em>B</em> within the root temporal extent;</p></li><li><p>add a <code>dur</code> attribute to the <code>[attributes]</code> information item property of <em>R'&nbsp;</em> with
+a value equivalent to the computed simple duration of <em>B</em>;</p></li></ul></li><li><p>if the TTML <a href="#terms-document-instance">document instance</a> does not have a
+<a href="#document-structure-vocabulary-head"><code>head</code></a> element, then insert an empty
+<a href="#document-structure-vocabulary-head"><code>head</code></a> element as the first child of
+the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element;</p></li><li><p>if the <a href="#document-structure-vocabulary-head"><code>head</code></a> element does not have
+a <a href="#layout-vocabulary-layout"><code>layout</code></a> child element, then insert an empty
+<a href="#layout-vocabulary-layout"><code>layout</code></a> element immediately after a
+<a href="#styling-vocabulary-styling"><code>styling</code></a> element, if present, and immediately before an
+<a href="#animation-vocabulary-styling"><code>animation</code></a> element, if present, or as the last child of
+the <a href="#document-structure-vocabulary-head"><code>head</code></a> element if neither are present;</p></li><li><p>append <em>R'&nbsp;</em> to the <code>[children]</code> information item property of the
+<a href="#layout-vocabulary-layout"><code>layout</code></a> element child of the 
+<a href="#document-structure-vocabulary-head"><code>head</code></a> element;</p></li><li><p>add a <a href="#layout-attribute-region"><code>region</code></a> attribute with value <em>ID</em> to the <code>[attributes]</code> information
+item property of <em>B</em>;</p></li><li><p>remove <em>R</em> from the <code>[children]</code> information item property of <em>B</em>;</p></li></ol><div class="issue"><p class="prefix"><a id="issue-324"></a><b>Issue (issue-324):</b></p><p class="prefix"><b>Duration Restrictions</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/324">http://www.w3.org/AudioVideo/TT/tracker/issues/324</a></p><p>Handle case where use of <code>dur</code> is not permitted, e.g., when using discontinuous SMPTE time base.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div></dd></dl><p>The use of an <em>implied inline region specification</em> and the resulting generated inline region is shown by the following two example documents.</p><a id="semantics-inline-region-input-example-1-implied"></a><table class="example"><caption>Example – Implied Inline Region Specification</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head/&gt;
+  &lt;body&gt;
+    &lt;div <span class="strong">tts:extent="540px 100px" tts:origin="50px 339px"</span>&gt;
+      &lt;p&gt;Some Content&lt;/p&gt;
+    &lt;div/&gt;
+  &lt;body/&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="semantics-generated-out-of-line-region-example-1-implied"></a><table class="example"><caption>Example – Generated Inline Region</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head/&gt;
+  &lt;body&gt;
+    &lt;div&gt;
+      <span class="strong">&lt;region tts:extent="540px 100px" tts:origin="50px 339px"/&gt;</span>
+      &lt;p&gt;Some Content&lt;/p&gt;
+    &lt;div/&gt;
+  &lt;body/&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p>The use of an <em>explicit inline region specification</em> or a generated inline region that derives from
+an <em>implicit inline region specification</em>
+and the resulting generated out-of-line region is shown by the following two example documents.</p><a id="semantics-inline-region-input-example-2-explicit"></a><table class="example"><caption>Example – Explicit or Generated Inline Region Specification</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head/&gt;
+  &lt;body&gt;
+    &lt;div begin="5s" dur="10s"&gt;
+      <span class="strong">&lt;region tts:extent="540px 100px" tts:origin="50px 339px"/&gt;</span>
+      &lt;p&gt;Some Content&lt;/p&gt;
+    &lt;div/&gt;
+  &lt;body/&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p></p><a id="semantics-generated-out-of-line-region-example-2-explicit"></a><table class="example"><caption>Example – Generated Out-of-line Region</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"&gt;
+  &lt;head&gt;
+    <span class="strong">&lt;layout&gt;
+      &lt;region xml:id="region3451" begin="5s" dur="10s" tts:extent="540px 100px" tts:origin="50px 339px"/&gt;
+    &lt;/layout&gt;</span>
+  &lt;/head&gt;
+  &lt;body&gt;
+    &lt;div begin="5s" dur="10s" <span class="strong">region="region3451"</span>&gt;
+      &lt;p&gt;Some Content&lt;/p&gt;
+    &lt;div/&gt;
+  &lt;body/&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table></div><div class="div4">
+<h5><a id="semantics-region-layout-step-1"></a>11.3.1.3 Intermediate Synchronic Document Construction</h5><table border="1" class="ednote" summary="Editorial note: Use Formalized ISD"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Use Formalized ISD</b></td><td align="right" valign="top">2014-09-22</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Revise in order to take into account new formalization of ISD structure and semantics (Appendix C).</td></tr></table><p>For the purposes of performing presentation processing, the active time
+duration of a <a href="#terms-document-instance">document instance</a> is divided into a sequence of time coordinates where at
+each time coordinate, some element becomes temporally active or inactive,
+then, at each such time coordinate, a <a href="#terms-document-instance">document instance</a> is mapped from its original, source
+form, <em>DOC<sub>source</sub></em> , 
+to an intermediate
+synchronic document form,
+<em>DOC<sub>inter</sub></em> , according to the
+<span class="strong"><a href="#procedure-construct-intermediate-document">[construct intermediate document]</a></span> procedure:</p><dl><dt class="label"><a id="procedure-construct-intermediate-document"></a>[construct intermediate document]</dt><dd><ol class="enumar"><li><p>perform procedure <span class="strong"><a href="#procedure-process-inline-regions">[process inline regions]</a></span>;</p></li><li><p>for each temporally active region <em>R</em>, replicate the
+sub-tree
+ of <em>DOC<sub>source</sub></em>
+headed by the <code>body</code> element;</p></li><li><p>evaluating this sub-tree in a postorder traversal, prune elements if they
+are not a <a href="#terms-content-element">content element</a>, if they are temporally inactive, if they are empty,
+or if they aren't associated with region <em>R</em> according to the
+<span class="strong"><a href="procedure-associate-region">[associate region]</a></span> procedure;</p></li><li><p>if the pruned sub-tree is non-empty, then reparent it to the <em>R</em>
+element;</p></li><li><p>finally, after completing the above steps, prune the original <code>body</code>
+element from the intermediate document, then prune all <code>region</code>,
+<code>begin</code>, <code>end</code>, and <code>dur</code> attributes, which are no
+longer semantically relevant;</p></li></ol><div class="note"><p class="prefix"><b>Note:</b></p><p>In this section, the term <em>prune</em>, when used in reference to
+an element, means that the element is to be removed from its parent's children,
+which, in turn, implies that the descendants of the pruned element will no longer
+be descendants of the element's parent. When <em>prune</em> is used in
+reference to an attribute, it means that attribute is to be removed from its
+associated (owning) element node.</p></div></dd><dt class="label"><a id="procedure-associate-region"></a>[associate region]</dt><dd><p></p><div class="issue"><p class="prefix"><a id="issue-341"></a><b>Issue (issue-341):</b></p><p class="prefix"><b>Multiple Descendant Region Ambiguitty</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/341">http://www.w3.org/AudioVideo/TT/tracker/issues/341</a></p><p>Refine step (3) to resolve ambiguity when multiple regions are referenced by descendants.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><table border="1" class="ednote" summary="Editorial note: Inline Region Association"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Inline Region Association</b></td><td align="right" valign="top">2013-08-28</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Define inline region association.</td></tr></table><p>A <a href="#terms-content-element">content element</a> is associated with a region according
+to the following ordered rules, where the first rule satisfied
+is used and remaining rules are skipped:</p><ol class="enumar"><li><p>if the element specifies a <a href="#layout-attribute-region"><code>region</code></a> attribute,
+then the element is associated with the region referenced by that
+attribute;</p></li><li><p>if some ancestor of that element specifies a <a href="#layout-attribute-region"><code>region</code></a> attribute,
+then the element is associated with the region referenced by the most
+immediate ancestor that specifies this attribute;</p></li><li><p> if the element contains a descendant element that
+specifies a <a href="#layout-attribute-region"><code>region</code></a> attribute,
+then the element is associated with the region referenced by that
+attribute;</p></li><li><p>if a default region was implied (due to the absence of any
+<a href="#layout-vocabulary-region"><code>region</code></a> element),
+then the element is associated with the default region;</p></li><li><p>the element is not associated with any region.</p></li></ol></dd></dl><p>The result of performing the processing described above will be a sequence of
+<em>N</em> intermediate  synchronic
+<a href="#terms-document-instance">document instances</a>,
+<em>DOC<sub><span>inter<sub>0</sub></span></sub></em> …
+<em>DOC<sub><span>inter<sub>N−1</sub></span></sub></em>.</p><div class="note" id="semantics-smooth-scrolling-recommendation"><p class="prefix"><b>Note:</b></p><p>Where an implementation is able to detect significant similarity between two
+adjacent synchronic <a href="#terms-document-instance">document instances</a>,
+<em>DOC<sub><span>inter<sub>N</sub></span></sub></em>
+<em>DOC<sub><span>inter<sub>N−1</sub></span></sub></em>,
+then it is preferred that the implementation make the transition between
+presenting the two instances as smooth as possible, e.g., as described
+by <a href="#cea608e">[CEA-608-E]</a>, § C.3, and <a href="#ccreq">[CC-DECODER-REQ]</a>.</p></div></div><div class="div4">
+<h5><a id="semantics-region-layout-step-2"></a>11.3.1.4 Synchronic Flow Processing</h5><p>Subsequent to performing a temporal (synchronic) slice and subsequent
+remapping of regionally selected content hierarchy, the resulting intermediate
+synchronic document is subjected to a flow transformation step that produces 
+a rooted flow object tree represented as an XSL FO document instance as defined by <a href="#xsl11">[XSL 1.1]</a>,
+and semantically extended by TTML specific style properties that have no XSL
+FO counterpart.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In this section, the use of XSL FO is intended to be conceptual only, employed
+solely for the purpose of defining the normative presentation semantics of
+TTML. An actual implementation of this algorithm is not required to create or process
+XSL-FO representations. In particular, it is possible to implement these semantics
+using alternative presentation models, such as Cascading Style Sheets (CSS).</p></div><p>Each intermediate synchronic document produced by <a href="#semantics-region-layout-step-1"><b>11.3.1.3 Intermediate Synchronic Document Construction</b></a> is mapped 
+to an XSL FO document instance, <em>F</em>, as follows:</p><ol class="enumar"><li><p>perform the following ordered sub-steps to create anonymous spans:</p><ol class="enumla"><li><p>for each significant text node in a <a href="#terms-content-element">content element</a>,
+synthesize an anonymous span to enclose the text node, substituting
+the new anonymous span for the original text node child in its sibling
+and parent hierarchy;</p></li><li><p>for each contiguous sequence of anonymous spans, replace the
+sequence with a single anonymous span which contains a sequence of
+text nodes representing the individual text node children of the
+original sequence of anonymous spans;</p></li><li><p>for each span element whose child is a single anonymous span,
+replace the anonymous span with its sequence of child text
+nodes;</p></li></ol></li><li><p>resolve styles according to <a href="#semantics-style-resolution-process-overall"><b>10.4.4.4 Style Resolution Process</b></a>;</p></li><li><p>map the <code>tt</code> element to an <code>fo:root</code> element, populated
+initially with an <code>fo:layout-master-set</code> element that contains a valid
+<code>fo:simple-page-master</code> that, in turn, contains an
+<code>fo:region-body</code> child, where the extent of the <a href="#terms-root-container-region">root container region</a> expressed on the
+<code>tt</code> element is mapped to <code>page-width</code> and
+<code>page-height</code> attributes on the <code>fo:simple-page-master</code>
+element;</p></li><li><p>map the <code>layout</code> element to an <code>fo:page-sequence</code> element and a
+child <code>fo:flow</code> element that reference the page master and page region
+defined by the simple page master produced above;</p></li><li><p>map each non-empty <code>region</code> element to an <code>fo:block-container</code>
+element with an <code>absolute-position</code> attribute with value
+<code>absolute</code>, with <code>top</code>, <code>left</code>, <code>bottom</code>, and <code>right</code>
+attributes that express a rectangle equivalent to the region's origin and
+extent, and with a <code>line-stacking-strategy</code> attribute with value <code>line-height</code>;</p></li><li><p>for each <code>body</code>, <code>div</code>, and <code>p</code> element that is not
+associated with a <code>tts:display</code> style property with the value
+<code>none</code>, map the element to a distinct <code>fo:block</code> element,
+populating the style properties of <code>fo:block</code> by using the computed
+style set associated with each original TTML <a href="#terms-content-element">content element</a>;</p></li><li><p>for the resulting <code>fo:block</code> formatting object
+produced in the previous step that corresponds to the <code>body</code>
+element, perform the following ordered sub-steps:</p><ol class="enumla"><li><p>if the <code>display-align</code> style property of this <code>fo:block</code>
+has the value <code>center</code> or <code>after</code>,
+then synthesize and insert as the first child of this <code>fo:block</code>
+an empty <code>fo:block</code> with the following attributes:
+<code>space-after.optimum</code>, <code>space-after.maximum</code>, and
+<code>space-after.conditionality</code>, where the value of the former
+two attributes is the height or width of the containing
+<code>fo:block-container</code> element, whichever of these is designated
+as the block progression dimension, and where the value of the last is
+<code>retain</code>;</p></li><li><p>if the <code>display-align</code> style property of this <code>fo:block</code>
+has the value <code>center</code> or <code>before</code>,
+then synthesize and insert as the last child of this <code>fo:block</code>
+an empty <code>fo:block</code> with the following attributes:
+<code>space-after.optimum</code>, <code>space-after.maximum</code>, and
+<code>space-after.conditionality</code>, where the value of the former
+two attributes is the height or width of the containing
+<code>fo:block-container</code> element, whichever of these is designated
+as the block progression dimension, and where the value of the last is
+<code>retain</code>;</p></li></ol></li><li><p>for each <code>span</code> element that is not
+associated with a <code>tts:display</code> style property with the value
+<code>none</code> and for each anonymous
+span that is a child of a <code>p</code> or <code>span</code> element,
+map the element or
+sequence of character items to a distinct <code>fo:inline</code> element,
+populating the style properties of <code>fo:inline</code> by using the computed
+style set associated with each original TTML <a href="#terms-content-element">content element</a>
+or anonymous span;</p></li><li><p>for each <code>br</code> element that is not
+associated with a <code>tts:display</code> style property with the value
+<code>none</code>, map the element to
+a distinct <code>fo:character</code> element having the following
+properties:</p><ul><li><p><code>character="&amp;#x000A;"</code></p></li><li><p><code>suppress-at-line-break="retain"</code></p></li></ul></li><li><p>for each TTML style property attribute in some computed
+style set that
+has no counterpart in <a href="#xsl11">[XSL 1.1]</a>, map that attribute directly through
+to the relevant formatting object produced by the input TTML <a href="#terms-content-element">content element</a> to
+which the style property applies;</p></li><li><p>optionally, synthesize a unique <code>id</code> attribute on each resulting
+formatting object element that relates that element to the input element that
+resulted in that formatting object element;</p></li></ol><p>For each resulting document instance F, if processing requires presentation on a 
+visual medium, then apply formatting and rendering semantics consistent with that 
+prescribed by <a href="#xsl11">[XSL 1.1]</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In an XSL FO area tree produced by formatting <em>F</em> using 
+an <a href="#xsl11">[XSL 1.1]</a> formatting processor, 
+the <code>page-viewport-area</code>,
+which is generated by <code>fo:page-sequence</code> element by
+reference to the sole generated <code>fo:simple-page-master</code>
+element, would correspond to the <a href="#terms-root-container-region">root container region</a> defined
+above in <a href="#definitions"><b>2 Definitions</b></a>.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>When mapping a <code>region</code> element to <code>fo:block-container</code>, it may
+be necessary to use a negative offset as a value for one or more of the
+<code>top</code>, <code>left</code>, <code>bottom</code>, and <code>right</code>
+XSL-FO properties in case the region extends outside of its containing block.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Due to the possible presence of TTML style properties or style property values
+in a given <a href="#terms-document-instance">document instance</a> for which there is no <a href="#xsl11">[XSL 1.1]</a> counterpart,
+Implementors should recognize that it is the layout model of <a href="#xsl11">[XSL 1.1]</a> that is being referenced
+by this specification, not the requirement to use a compliant <a href="#xsl11">[XSL 1.1]</a> formatting processor,
+since such would not necessarily be sufficient to satisfy the full presentation semantics
+defined by this specification, and would contain a large number of features not needed to
+implement the presentation semantics of TTML.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The purpose of inserting additional, collapsible space in the block progression
+dimension of the <code>fo:block</code> that corresponds with the <code>body</code> element
+is to ensure that the before and after edges of this <code>fo:block</code> are coincident
+with the before and after edges of the <code>fo:block-container</code> that corresponds
+to the containing <code>region</code>, while simultaneously taking into account the needs
+to satisfy alignment in the block progression dimension. For example, this assures that
+the background color associated with the <code>body</code> element, if not <code>transparent</code>,
+ will fill the containing region wholly.</p></div></div><div class="div4">
+<h5><a id="semantics-region-layout-example"></a>11.3.1.5 Elaborated Example (Non-Normative)</h5><p>An example of the processing steps described above is elaborated below, starting with <a href="#region-mapping-example-1-s"><b>Example – Sample Source Document</b></a>.</p><a id="region-mapping-example-1-s"></a><table class="example"><caption>Example – Sample Source Document</caption><tbody><tr><td>
+<div class="exampleInner"><pre>&lt;tt tts:extent="640px 480px" xml:lang="en"
+  xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;head&gt;
+    &lt;layout&gt;
+      &lt;region xml:id="r1"&gt;
+        &lt;style tts:origin="10px 100px"/&gt;
+        &lt;style tts:extent="620px 96px"/&gt;
+        &lt;style tts:fontSize="40px"/&gt;
+        &lt;style tts:fontWeight="bold"/&gt;
+        &lt;style tts:backgroundColor="black"/&gt;
+        &lt;style tts:color="red"/&gt;
+        &lt;style tts:textAlign="center"/&gt;
+        &lt;style tts:displayAlign="center"/&gt;
+      &lt;/region&gt;
+      &lt;region xml:id="r2"&gt;
+        &lt;style tts:origin="10px 300px"/&gt;
+        &lt;style tts:extent="620px 96px"/&gt;
+        &lt;style tts:fontSize="40px"/&gt;
+        &lt;style tts:fontWeight="bold"/&gt;
+        &lt;style tts:backgroundColor="black"/&gt;
+        &lt;style tts:color="yellow"/&gt;
+        &lt;style tts:textAlign="center"/&gt;
+        &lt;style tts:displayAlign="center"/&gt;
+      &lt;/region&gt;
+    &lt;/layout&gt;
+  &lt;/head&gt;
+  &lt;body xml:id="b1"&gt;
+    &lt;div xml:id="d1" begin="0s" dur="2s"&gt;
+      &lt;p xml:id="p1" region="r1"&gt;Text 1&lt;/p&gt;
+      &lt;p xml:id="p2" region="r2"&gt;Text 2&lt;/p&gt;
+    &lt;/div&gt;
+    &lt;div xml:id="d2" begin="1s" dur="2s"&gt;
+      &lt;p xml:id="p3" region="r2"&gt;Text 3&lt;/p&gt;
+      &lt;p xml:id="p4" region="r1"&gt;Text 4&lt;/p&gt;
+    &lt;/div&gt;
+  &lt;/body&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p>In the above document, the content hierarchy consists of two divisions, each
+containing two paragraphs. This content is targeted (associated with) one of two
+non-overlapping regions that are styled identically except for their position
+and their foreground colors, the latter of which is inherited by and applies to
+the (and, in this case, anonymous) spans reparented into the regions.</p><p>The following, first intermediate document shows the synchronic state for time
+interval [0,1), during which time only division <code>d1</code> is temporally active,
+and where paragraphs <code>p1</code> and <code>p2</code> (and their ancestors)
+are associated with regions <code>r1</code> and <code>r2</code>, respectively.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The intermediate documents shown below are not valid <a href="#terms-document-instance">document instances</a>,
+but rather, are representations of possible internal processing states used for
+didactic purposes.</p></div><a id="region-mapping-example-1-i0"></a><table class="example"><caption>Example – Intermediate Document – [0s,1s)</caption><tbody><tr><td>
+<div class="exampleInner"><pre>&lt;tt tts:extent="640px 480px" xml:lang="en"
+  xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;head&gt;
+    &lt;layout&gt;
+      &lt;region xml:id="r1"&gt;
+        &lt;style tts:origin="10px 100px"/&gt;
+        &lt;style tts:extent="620px 96px"/&gt;
+        &lt;style tts:fontSize="40px"/&gt;
+        &lt;style tts:fontWeight="bold"/&gt;
+        &lt;style tts:backgroundColor="black"/&gt;
+        &lt;style tts:color="red"/&gt;
+        &lt;style tts:textAlign="center"/&gt;
+        &lt;style tts:displayAlign="center"/&gt;
+        &lt;body xml:id="b1-1"&gt;
+          &lt;div xml:id="d1-1"&gt;
+            &lt;p xml:id="p1"&gt;Text 1&lt;/p&gt;
+          &lt;/div&gt;
+        &lt;/body&gt;
+      &lt;/region&gt;
+      &lt;region xml:id="r2"&gt;
+        &lt;style tts:origin="10px 300px"/&gt;
+        &lt;style tts:extent="620px 96px"/&gt;
+        &lt;style tts:fontSize="40px"/&gt;
+        &lt;style tts:fontWeight="bold"/&gt;
+        &lt;style tts:backgroundColor="black"/&gt;
+        &lt;style tts:color="yellow"/&gt;
+        &lt;style tts:textAlign="center"/&gt;
+        &lt;style tts:displayAlign="center"/&gt;
+        &lt;body xml:id="b1-2"&gt;
+          &lt;div xml:id="d1-2"&gt;
+            &lt;p xml:id="p2"&gt;Text 2&lt;/p&gt;
+          &lt;/div&gt;
+        &lt;/body&gt;
+      &lt;/region&gt;
+    &lt;/layout&gt;
+  &lt;/head&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p>An XSL FO document instance that would yield rendering consistent with TTML, and 
+which may be produced by performing flow processing upon the first intermediate 
+document is illustrated below.</p><a id="region-mapping-example-1-f0"></a><table class="example"><caption>Example – XSL FO Document – [0s,1s)</caption><tbody><tr><td>
+<div class="exampleInner"><pre>&lt;fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format"&gt;
+  &lt;fo:layout-master-set&gt;
+    &lt;fo:simple-page-master master-name="m1"
+      page-width="640px" page-height="480px"&gt;
+      &lt;fo:region-body/&gt;
+    &lt;/fo:simple-page-master&gt;
+  &lt;/fo:layout-master-set&gt;
+  &lt;fo:page-sequence master-reference="m1"&gt;
+    &lt;fo:flow flow-name="xsl-region-body"&gt;
+      &lt;!-- region (r1) --&gt;
+      &lt;fo:block-container id="r1" absolute-position="absolute"
+        left="10px" top="100px" width="620px" height="96px"
+        background-color="black" display-align="center"&gt;
+        &lt;!-- body (b1) --&gt;
+        &lt;fo:block id="b1-1"&gt;
+          &lt;!-- body's space (before) filler --&gt;
+          &lt;fo:block
+            space-after.optimum="96px"
+            space-after.maximum="96px"
+            space-after.conditionality="retain"/&gt;
+          &lt;!-- div (d1) --&gt;
+          &lt;fo:block id="d1-1"&gt;
+            &lt;!-- p (p1) --&gt;
+            &lt;fo:block id="p1" text-align="center"&gt;
+              &lt;fo:inline font-size="40px" font-weight="bold"
+              color="red"&gt;Text 1&lt;/fo:inline&gt;
+            &lt;/fo:block&gt;
+          &lt;/fo:block&gt;
+          &lt;!-- body's space (after) filler --&gt;
+          &lt;fo:block
+            space-after.optimum="96px"
+            space-after.maximum="96px"
+            space-after.conditionality="retain"/&gt;
+        &lt;/fo:block&gt;
+      &lt;/fo:block-container&gt;
+      &lt;!-- region (r2) --&gt;
+      &lt;fo:block-container id="r2" absolute-position="absolute"
+        left="10px" top="300px" width="620px" height="96px"
+        background-color="black" display-align="center"&gt;
+        &lt;!-- body (b1) --&gt;
+        &lt;fo:block id="b1-2"&gt;
+          &lt;!-- body's space (before) filler --&gt;
+          &lt;fo:block
+            space-after.optimum="96px"
+            space-after.maximum="96px"
+            space-after.conditionality="retain"/&gt;
+          &lt;!-- div (d1) --&gt;
+          &lt;fo:block id="d1-2"&gt;
+            &lt;!-- p (p2) --&gt;
+            &lt;fo:block id="p2" text-align="center"&gt;
+              &lt;fo:inline font-size="40px" font-weight="bold"
+              color="yellow"&gt;Text 2&lt;/fo:inline&gt;
+            &lt;/fo:block&gt;
+          &lt;/fo:block&gt;
+          &lt;!-- body's space (after) filler --&gt;
+          &lt;fo:block
+            space-after.optimum="96px"
+            space-after.maximum="96px"
+            space-after.conditionality="retain"/&gt;
+        &lt;/fo:block&gt;
+      &lt;/fo:block-container&gt;
+    &lt;/fo:flow&gt;
+  &lt;/fo:page-sequence&gt;
+&lt;/fo:root&gt;
+</pre></div>
+</td></tr></tbody></table><p>The following, second intermediate document shows the synchronic state for
+time interval [1,2), during which time both divisions <code>d1</code> and
+<code>d2</code> are temporally active, and where paragraphs <code>p1</code> and
+<code>p4</code> (and their ancestors) are associated with region <code>r1</code>
+and paragraphs <code>p2</code> and <code>p3</code> (and their ancestors) are
+associated with region <code>r2</code>.</p><a id="region-mapping-example-1-i1"></a><table class="example"><caption>Example – Intermediate Document – [1s,2s)</caption><tbody><tr><td>
+<div class="exampleInner"><pre>&lt;tt tts:extent="640px 480px" xml:lang="en"
+  xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;head&gt;
+    &lt;layout&gt;
+      &lt;region xml:id="r1"&gt;
+        &lt;style tts:origin="10px 100px"/&gt;
+        &lt;style tts:extent="620px 96px"/&gt;
+        &lt;style tts:fontSize="40px"/&gt;
+        &lt;style tts:fontWeight="bold"/&gt;
+        &lt;style tts:backgroundColor="black"/&gt;
+        &lt;style tts:color="red"/&gt;
+        &lt;style tts:textAlign="center"/&gt;
+        &lt;style tts:displayAlign="center"/&gt;
+        &lt;body xml:id="b1-1"&gt;
+          &lt;div xml:id="d1-1"&gt;
+            &lt;p xml:id="p1"&gt;Text 1&lt;/p&gt;
+          &lt;/div&gt;
+          &lt;div xml:id="d2-1"&gt;
+            &lt;p xml:id="p4"&gt;Text 4&lt;/p&gt;
+          &lt;/div&gt;
+        &lt;/body&gt;
+      &lt;/region&gt;
+      &lt;region xml:id="r2"&gt;
+        &lt;style tts:origin="10px 300px"/&gt;
+        &lt;style tts:extent="620px 96px"/&gt;
+        &lt;style tts:fontSize="40px"/&gt;
+        &lt;style tts:fontWeight="bold"/&gt;
+        &lt;style tts:backgroundColor="black"/&gt;
+        &lt;style tts:color="yellow"/&gt;
+        &lt;style tts:textAlign="center"/&gt;
+        &lt;style tts:displayAlign="center"/&gt;
+        &lt;body xml:id="b1-2"&gt;
+          &lt;div xml:id="d1-2"&gt;
+            &lt;p xml:id="p2"&gt;Text 2&lt;/p&gt;
+          &lt;/div&gt;
+          &lt;div xml:id="d2-2"&gt;
+            &lt;p xml:id="p3"&gt;Text 3&lt;/p&gt;
+          &lt;/div&gt;
+        &lt;/body&gt;
+      &lt;/region&gt;
+    &lt;/layout&gt;
+  &lt;/head&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><p>The following, third intermediate document shows the synchronic state for time
+interval [2,3), during which time only division <code>d2</code> is temporally active,
+and where paragraphs <code>p4</code> and <code>p3</code> (and their ancestors)
+are associated with regions <code>r1</code> and <code>r2</code>, respectively.</p><a id="region-mapping-example-1-i2"></a><table class="example"><caption>Example – Intermediate Document – [2s,3s)</caption><tbody><tr><td>
+<div class="exampleInner"><pre>&lt;tt tts:extent="640px 480px" xml:lang="en"
+  xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;head&gt;
+    &lt;layout&gt;
+      &lt;region xml:id="r1"&gt;
+        &lt;style tts:origin="10px 100px"/&gt;
+        &lt;style tts:extent="620px 96px"/&gt;
+        &lt;style tts:fontSize="40px"/&gt;
+        &lt;style tts:fontWeight="bold"/&gt;
+        &lt;style tts:backgroundColor="black"/&gt;
+        &lt;style tts:color="red"/&gt;
+        &lt;style tts:textAlign="center"/&gt;
+        &lt;style tts:displayAlign="center"/&gt;
+        &lt;body xml:id="b1-1"&gt;
+          &lt;div xml:id="d2-1"&gt;
+            &lt;p xml:id="p4"&gt;Text 4&lt;/p&gt;
+          &lt;/div&gt;
+        &lt;/body&gt;
+      &lt;/region&gt;
+      &lt;region xml:id="r2"&gt;
+        &lt;style tts:origin="10px 300px"/&gt;
+        &lt;style tts:extent="620px 96px"/&gt;
+        &lt;style tts:fontSize="40px"/&gt;
+        &lt;style tts:fontWeight="bold"/&gt;
+        &lt;style tts:backgroundColor="black"/&gt;
+        &lt;style tts:color="yellow"/&gt;
+        &lt;style tts:textAlign="center"/&gt;
+        &lt;style tts:displayAlign="center"/&gt;
+        &lt;body xml:id="b1-2"&gt;
+          &lt;div xml:id="d2-2"&gt;
+            &lt;p xml:id="p3"&gt;Text 3&lt;/p&gt;
+          &lt;/div&gt;
+        &lt;/body&gt;
+      &lt;/region&gt;
+    &lt;/layout&gt;
+  &lt;/head&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table></div></div><div class="div3">
+<h4><a id="semantics-line-layout"></a>11.3.2 Line Layout</h4><p>If a profile that applies to a <a href="#terms-document-instance">document instance</a>
+requires use of the <a href="#feature-lineBreak-uax14">#lineBreak-uax14</a> feature
+(i.e., the value attribute for the feature is specified as <code>use</code>), then
+the recommendations defined by <a href="http://www.unicode.org/reports/tr14/#Algorithm">Line
+Breaking Algorithm</a> <a href="#uax14">[UAX14]</a> apply when performing
+line layout on the content of the <a href="#terms-document-instance">document instance</a>.</p></div></div></div><div class="div1">
+<h2><a id="timing"></a>12 Timing</h2><p>This section specifies the <em>timing</em> matter of the core
+vocabulary catalog, where
+timing is to be understood as a separable layer of information that applies to
+content and that denotes authorial intentions about the temporal presentation of
+that content.</p><div class="div2">
+<h3><a id="timing-element-vocabulary"></a>12.1 Timing Element Vocabulary</h3><p>No timing related element vocabulary is defined for use in the core
+vocabulary catalog.</p></div><div class="div2">
+<h3><a id="timing-attribute-vocabulary"></a>12.2 Timing Attribute Vocabulary</h3><p>This section defines the following basic timing attributes for use with timed elements:</p><ul><li><p><a href="#timing-attribute-begin"><b>12.2.1 begin</b></a></p></li><li><p><a href="#timing-attribute-dur"><b>12.2.2 dur</b></a></p></li><li><p><a href="#timing-attribute-end"><b>12.2.3 end</b></a></p></li></ul><p>In addition, this section defines the <a href="#timing-attribute-timeContainer"><b>12.2.4 timeContainer</b></a> attribute for use with timed elements
+that serve simultaneously as timing containers.</p><div class="div3">
+<h4><a id="timing-attribute-begin"></a>12.2.1 begin</h4><p>The <code>begin</code> attribute is used to specify the begin
+point of a temporal interval associated with a timed element. If
+specified, the value of a <code>begin</code> attribute must adhere to
+a &lt;timeExpression&gt; specification as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>The begin point of a temporal interval is included in the
+interval; i.e., the interval is left-wise closed.</p><p>The semantics of the <code>begin</code> attribute are those defined
+by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3,
+while taking into account any overriding semantics defined by this specification.</p></div><div class="div3">
+<h4><a id="timing-attribute-dur"></a>12.2.2 dur</h4><p>The <code>dur</code> attribute is used to specify the duration of a
+temporal interval associated with a timed element. If specified,
+the value of a <code>dur</code> attribute must adhere to a
+&lt;timeExpression&gt; specification as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When the <code>clock-time</code> form of a &lt;timeExpression&gt; specification
+is used with a <code>dur</code> attribute, it is intended to be interpreted as
+a difference between two implied clock time expressions.</p></div><p>When a <a href="#terms-document-instance">document instance</a> specifies the use of the
+<code>smpte</code> time base and <code>discontinuous</code> marker
+mode, a (well-formed) <code>dur</code> attribute must not be specified on any
+element.</p><p>The semantics of the <code>dur</code> attribute are those defined
+by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3,
+while taking into account any overriding semantics defined by this specification.
+In a deliberate divergence from <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3, the value of
+the <code>dur</code> attribute is permitted to be zero (0).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In the context of the subset of <a href="#smil3">[SMIL 3.0]</a> semantics supported by
+this specification, the active duration of an element that specifies both
+<code>end</code> and <code>dur</code> attributes is equal to the lesser of the value of
+the <code>dur</code> attribute and the difference between the value of the
+<code>end</code> attribute and the element's begin time.</p></div></div><div class="div3">
+<h4><a id="timing-attribute-end"></a>12.2.3 end</h4><p>The <code>end</code> attribute is used to specify the ending point
+of a temporal interval associated with a timed element. If
+specified, the value of an <code>end</code> attribute must adhere to a
+&lt;timeExpression&gt; specification as defined by <a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a>.</p><p>The ending point of a temporal interval is not included in the
+interval; i.e., the interval is right-wise open.</p><p>The presentation effects of a non-empty active
+temporal interval include the frame immediately prior to the frame
+(or tick) equal to or immediately following the time specified by the ending
+point, but do not extend into this latter frame (or tick).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, if an active interval is [10s,10.33333s), and the
+frame rate is 30 frames per second, then the presentation effects of the interval
+are limited to frames 300 through 309 only (assuming that 0s corresponds
+with frame 0). The same holds if the active interval is specified
+as [300f,310f).</p></div><p>The semantics of the <code>end</code> attribute are those defined
+by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.3,
+while taking into account any overriding semantics defined by this specification.</p></div><div class="div3">
+<h4><a id="timing-attribute-timeContainer"></a>12.2.4 timeContainer</h4><p>The <code>timeContainer</code> attribute is used to specify a local temporal
+context by means of which timed child elements are temporally situated.</p><p>If specified, the value of a <code>timeContainer</code> attribute must be one
+of the following:</p><ul><li><p><code>par</code></p></li><li><p><code>seq</code></p></li></ul><p>If the time container semantics of an element instance is <code>par</code>,
+then the temporal intervals of child elements are considered to apply in
+parallel, i.e., simultaneously in time. Furthermore, the specification of
+the time interval of each child element is considered to be relative to the temporal
+interval of the container element instance. For the purpose of determining the
+<a href="#smil3">[SMIL 3.0]</a> <code>endsync</code> semantics of a <code>par</code>
+time container, a default value of <code>all</code> applies.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The use of a default value of <code>all</code> for the <code>endsync</code>
+behavior is distinct from <a href="#smil3">[SMIL 3.0]</a> which uses a default value
+of <code>last</code>.</p></div><p>If the time container semantics of an element instance is <code>seq</code>,
+then the temporal intervals of child elements are considered to apply in
+sequence, i.e., sequentially in time. Furthermore, the specification of
+the time interval of each child element is considered to be relative to the temporal
+interval of its sibling elements, unless it is the first child element, in which case
+it is considered to be relative to the temporal interval of the container
+element instance.</p><p>Each time container is considered to constitute an independent time base, i.e.,
+time coordinate system.</p><p>If a <code>timeContainer</code> attribute is not specified on an element that
+has time container semantics, then <code>par</code> time container semantics must apply.</p><p>Time container semantics applies only to the following element types:</p><ul><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li></ul><p>The semantics of parallel and sequential time
+containment are those defined by <a href="#smil3">[SMIL 3.0]</a>, § 5.4.4,
+while taking into account any overriding semantics defined by this specification.</p></div></div><div class="div2">
+<h3><a id="timing-time-value-expressions"></a>12.3 Time Value Expressions</h3><p>Timing attribute values include the use of the following expressions:</p><ul><li><p><a href="#timing-value-timeExpression"><b>12.3.1 &lt;timeExpression&gt;</b></a></p></li></ul><div class="div3">
+<h4><a id="timing-value-timeExpression"></a>12.3.1 &lt;timeExpression&gt;</h4><p>A &lt;timeExpression&gt; is used to specify a coordinate within
+some time base, where the applicable time base is determined by the
+<code>ttp:timeBase</code> parameter, and where the semantics defined
+by <a href="#time-expression-semantics"><b>H Time Expression Semantics</b></a> apply.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See
+<a href="#parameter-attribute-frameRate"><b>7.2.4 ttp:frameRate</b></a>,
+<a href="#parameter-attribute-subFrameRate"><b>7.2.11 ttp:subFrameRate</b></a>,
+<a href="#parameter-attribute-tickRate"><b>7.2.12 ttp:tickRate</b></a>, and
+<a href="#parameter-attribute-timeBase"><b>7.2.13 ttp:timeBase</b></a> for further information on
+explicit specification of frame rate, sub-frame rate, tick rate, and time base.</p></div><div class="issue"><p class="prefix"><a id="issue-293"></a><b>Issue (issue-293):</b></p><p class="prefix"><b>Dates in Time Expressions</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/293">http://www.w3.org/AudioVideo/TT/tracker/issues/293</a></p><p>Consider adding dates to time expressions to handle issues around midnight crossings and related use cases.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><a id="timeExpression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;timeExpression&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;timeExpression&gt;
+  : clock-time
+  | offset-time
+
+clock-time
+  : hours ":" minutes ":" seconds ( fraction | ":" frames ( "." sub-frames )? )?
+
+offset-time
+  : time-count fraction? metric?
+
+hours
+  : <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>
+  | <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>+
+
+minutes | seconds
+  : <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>
+
+frames
+  : <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>
+  | <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a> <a href="#style-value-digit">&lt;digit&gt;</a>+
+
+sub-frames
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+
+fraction
+  : "." <a href="#style-value-digit">&lt;digit&gt;</a>+
+
+time-count
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+
+metric
+  : "h"                 // hours
+  | "m"                 // minutes
+  | "s"                 // seconds
+  | "ms"                // milliseconds
+  | "f"                 // frames
+  | "t"                 // ticks
+</pre></div>
+</td></tr></tbody></table><p>If a &lt;timeExpression&gt; is expressed in terms of a
+<em>clock-time</em>, then leading zeroes are used when expressing hours,
+minutes, seconds, and frames less than 10. Minutes are constrained to
+[0…59], while seconds (including any fractional part) are constrained to the closed
+interval [0,60], where the value 60 applies only to leap seconds.</p><p>If a &lt;timeExpression&gt; is expressed in terms of a
+<em>clock-time</em> and a <em>frames</em> term is specified,
+then the value of this term must be constrained to the interval
+[0…<em>F-1</em>], where <em>F</em> is the frame rate
+determined by the <code>ttp:frameRate</code> parameter as defined
+by <a href="#parameter-attribute-frameRate"><b>7.2.4 ttp:frameRate</b></a>.
+It is considered an error if a <em>frames</em> term or
+<code>f</code> (frames) metric is specified when the <code>clock</code> time base applies.</p><p>If a &lt;timeExpression&gt; is expressed in terms of a
+<em>clock-time</em> and a <em>sub-frames</em> term is
+specified, then the value of this term must be constrained to the
+interval [0…<em>S-1</em>], where <em>S</em> is the
+sub-frame rate determined by the <code>ttp:subFrameRate</code> parameter as defined by <a href="#parameter-attribute-subFrameRate"><b>7.2.11 ttp:subFrameRate</b></a>.
+It is considered an error if a <em>sub-frames</em> term is specified
+when the <code>clock</code> time base applies.</p><p>If a &lt;timeExpression&gt; is expressed in terms of an
+<em>offset-time</em> and no <em>metric</em> is specified, then it is to be treated as
+if a metric of <code>s</code> (seconds) were specified.</p></div></div><div class="div2">
+<h3><a id="semantics-timing"></a>12.4 Timing Semantics</h3><p>The semantics of time containment, durations, and intervals defined by
+<a href="#smil3">[SMIL 3.0]</a> apply to the interpretation of like-named timed elements and timing
+vocabulary defined by this specification, given the following
+constraints:</p><div class="issue"><p class="prefix"><a id="issue-338"></a><b>Issue (issue-338):</b></p><p class="prefix"><b>Implicit Duration of Singleton Span</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/338">http://www.w3.org/AudioVideo/TT/tracker/issues/338</a></p><p>Refine definition implicit duration of singleton span in a sequential container.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><ul><li><p>The implicit duration of an anonymous span is defined as follows: if
+the anonymous span's parent time container is a parallel time container, then
+the implicit duration is equivalent to the <code>indefinite</code>
+duration value as defined by <a href="#smil3">[SMIL 3.0]</a>; if the anonymous span's
+parent time container is a sequential time container, then the implicit duration
+is equivalent to zero.</p></li><li><p>The implicit duration of a <code>body</code>, <code>div</code>, <code>p</code>,
+or <code>span</code> element is determined in accordance to (1) whether
+the element is a parallel or sequential time container, (2) the default
+<code>endsync</code> semantics defined above by <a href="#timing-attribute-timeContainer"><b>12.2.4 timeContainer</b></a>,
+and (3) the semantics of <a href="#smil3">[SMIL 3.0]</a> as applied to these time
+containers.</p></li><li><p>The implicit duration of the <code>region</code> element is defined to
+be equivalent to the <code>indefinite</code>
+duration value as defined by <a href="#smil3">[SMIL 3.0]</a>.</p></li><li><p>If the governing time base is <code>clock</code>, then time
+expressions are considered to be equivalent to wall-clock
+based timing in <a href="#smil3">[SMIL 3.0]</a>, where the specific semantics of
+<a href="#time-expression-semantics-clock"><b>H.1 Clock Time Base</b></a> apply.</p></li><li><p>If the governing time base is <code>media</code>, then time
+expressions are considered to be equivalent to offset based timing
+in <a href="#smil3">[SMIL 3.0]</a>, where the specific semantics of
+<a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> apply.</p></li><li><p>If the governing time base is <code>smpte</code>, then time
+expressions are considered to be equivalent to either offset
+based timing or event based timing in <a href="#smil3">[SMIL 3.0]</a>, where the specific semantics of
+<a href="#time-expression-semantics-smpte"><b>H.3 SMPTE Time Base</b></a> apply.</p></li></ul></div></div><div class="div1">
+<h2><a id="animation"></a>13 Animation</h2><p>This section specifies the <em>animation</em> matter of the
+core vocabulary catalog, where
+animation is to be understood as a separable layer of information that combines
+timing and styling in order to denote authorial intention about (temporally) dynamic
+styling of content.</p><table border="1" class="ednote" summary="Editorial note: Out-of-Line Animation Time Containment"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Out-of-Line Animation Time Containment</b></td><td align="right" valign="top">2014-07-31</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Support ability for author to declare whether a referenced out-of-line animation's timing is relative
+to its <code>animation</code> container element's timing or relative to the referring element's timing.
+For example, add an <code>@animateTimeContainer</code> attribute optionally used with the newly defined
+<code>@animate</code> attribute, where value can be <code>normal</code> (the default value) or <code>self</code>, and where <code>normal</code>
+means timing is with respect to the out-of-line animation element's ancestor <code>animation</code> container and <code>self</code> means timing is
+with respect to the referring element.</td></tr></table><div class="div2">
+<h3><a id="animation-element-vocabulary"></a>13.1 Animation Element Vocabulary</h3><p>The following elements specify the structure and principal animation aspects of a
+<a href="#terms-document-instance">document instance</a>:</p><ul><li><p><a href="#animation-vocabulary-animate"><b>13.1.1 animate</b></a></p></li><li><p><a href="#animation-vocabulary-animation"><b>13.1.2 animation</b></a></p></li><li><p><a href="#animation-vocabulary-set"><b>13.1.3 set</b></a></p></li></ul><div class="div3">
+<h4><a id="animation-vocabulary-animate"></a>13.1.1 animate</h4><p>The <code>animate</code> element expresses a series of changes (animations) to be applied (targeted) to one or more style property attributes of associated elements.</p><div class="issue"><p class="prefix"><a id="issue-355"></a><b>Issue (issue-355):</b></p><p class="prefix"><b>Marquee</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/355">http://www.w3.org/AudioVideo/TT/tracker/issues/355</a></p><p>Consider whether semantics of ARIB-TT's marquee extension can be handled by <code>animate</code>, and, if not, then consider extending.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>An <code>animate</code> element may appear as either (1) a child of a
+<a href="#terms-content-element">content element</a> or a <a href="#layout-vocabulary-region"><code>region</code></a> element,
+referred to as <a href="#terms-inline-animation">inline animation</a>, or
+(2) a child of an <a href="#animation-vocabulary-animation">animation</a> element, referred to as
+<a href="#terms-out-of-line-animation">out-of-line animation</a>.
+In the former case, the parent of the <code>animate</code> element is the associated element; in the latter
+case, any element that references the <code>animate</code> element using an <code>animate</code> attribute is
+an associated element.</p><p>The <code>animate</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group.</p><a id="elt-syntax-animate"></a><table class="syntax"><caption>XML Representation – Element Information Item: animate</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;animate
+  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  calcMode = <a href="#animation-value-calcMode">&lt;calcMode&gt;</a>
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  fill = <a href="#animation-value-fill">&lt;fill&gt;</a>
+  keySplines = <a href="#animation-value-keySplines">&lt;keySplines&gt;</a>
+  keyTimes = <a href="#animation-value-keyTimes">&lt;keyTimes&gt;</a>
+  repeatCount = <a href="#animation-value-repeatCount">&lt;repeatCount&gt;</a>
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
+&lt;/animate&gt;
+</pre></div>
+</td></tr></tbody></table><p>An <a href="#terms-out-of-line-animation">out-of-line</a> <code>animate</code> element
+must specify an <a href="#content-attribute-xml-id"><code>xml:id</code></a> attribute.</p><p>Style property attributes targeted by an <code>animate</code> element are specified directly using
+attributes in the TT Style namespace or in a namespace that is not a TT namespace, where the list (sequence) of animation (key) values
+adhere to the <a href="#animation-value-animationValueList">&lt;animationValueList&gt;</a> syntax, and where each
+constituent <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> adheres to the syntax of the specified
+attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In contrast with <a href="#svg11">[SVG 1.1]</a>, §19.2.12, a single <code>animate</code> element, as defined here, may be used to
+perform continuous animations on a set of targeted style property attributes instead of being limited to targeting a single style property attribute.
+In <a href="#svg11">[SVG 1.1]</a>, this would require the use of multiple <code>animate</code> elements rather than a single <code>animate</code> element.</p><p>Furthermore, by using direct specification of animated style property and key values, it is not necessary to employ the <code>from</code>,
+<code>to</code>, <code>by</code>, or <code>values</code> animation value attributes defined by <a href="#svg11">[SVG 1.1]</a>, §19.2.9.</p></div><p>Except for the constraints or variations enumerated below, the semantics of the <code>animate</code> element and its attributes
+enumerated above are defined to be those specified by <a href="#svg11">[SVG 1.1]</a>, §19.2.12:</p><ol class="enumar"><li><p>The attributes targeted by an <code>animate</code> element and the key values to be applied to these attributes are
+specified by direct use of attributes in the TT Style namespace or a namespace that is not a TT namespace (as opposed to using
+SVG's <code>attributeName</code> and <code>from</code>,  <code>to</code>, <code>by</code>, or <code>values</code> attributes).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, specifying <code>tts:color="red;green;blue"</code> is
+considered equivalent to specifying <code>attributeName="tts:color"</code> and <code>values="red;green;blue"</code> in <a href="#svg11">[SVG 1.1]</a>.</p></div></li><li><p>If no <code>calcMode</code> attribute is specified, then a <em>calcMode</em> value of <code>linear</code> applies.</p></li><li><p>If no <code>fill</code> attribute is specified, then a <em>fill</em> value of <code>remove</code> applies.</p></li></ol><p>An example of using the <code>animate</code> element to animate content
+styling is illustrated below:</p><a id="animation-vocabulary-animate-example-1"></a><table class="example"><caption>Example Fragment – Content Style Animation</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;p dur="5s"&gt;
+<span class="strong">&lt;animate tts:color="yellow;red;green;blue;yellow"/&gt;</span>
+Text with Continuously Varying Colors!
+&lt;/p&gt;
+...
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the foreground color of the content "Text
+with Continuously Varying Colors!" is continuously animated from yellow, to red, to green, to
+red, then back to yellow over a 5 second period.</p></div><p>An example of using the <code>animate</code> element to animate region
+styling is illustrated below:</p><a id="animation-vocabulary-animate-example-2"></a><table class="example"><caption>Example Fragment – Region Style Animation</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"
+    xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
+    xmlns:tts="http://www.w3.org/ns/ttml#styling"
+    ttp:extent="640px 480px"&gt;
+    &lt;head&gt;
+      &lt;layout&gt;
+	&lt;region xml:id="r1" timeContainer="seq" tts:opacity="0"&gt;
+	  <span class="strong">&lt;animate dur="1s" tts:opacity="0;1"/&gt;</span>
+	  &lt;set dur="5s" tts:opacity="1"/&gt;
+	  <span class="strong">&lt;animate dur="1s" tts:opacity="1;0"/&gt;</span>
+	  &lt;style tts:extent="480px 60px"/&gt;
+	  &lt;style tts:origin="80px 400px"/&gt;
+	&lt;/region&gt;
+      &lt;/layout&gt;
+    &lt;/head&gt;
+    &lt;body region="r1"&gt;...&lt;/body&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, a region, <code>r1</code>, is initially set to 0% opacity,
+fully transparent, then is faded in to 100% opacity, fully opaque, over a one second
+interval. Opacity remains at 100% for five more seconds, and then is faded out to 0%
+over a one second interval, where it remains.</p></div><p></p><table border="1" class="ednote" summary="Editorial note: Animate Example Images"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Animate Example Images</b></td><td align="right" valign="top">2013-08-25</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert animated SVG images of animate examples.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the <code>animate</code> element
+are based upon that defined by <a href="#svg11">[SVG 1.1]</a>,
+§19.2.12, which, in turn, is based upon <a href="#smil3">[SMIL 3.0]</a>, §12.</p></div></div><div class="div3">
+<h4><a id="animation-vocabulary-animation"></a>13.1.2 animation</h4><p>The <code>animation</code> element is a container element used to group
+<a href="#terms-out-of-line-animation">out-of-line animation</a> matter, including metadata that applies to animation matter.</p><p>The <code>animation</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group, followed by
+zero or more elements in the <a href="#element-vocab-group-animation"><code>Animation.class</code></a> element group.</p><a id="elt-syntax-animation"></a><table class="syntax"><caption>XML Representation – Element Information Item: animation</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;animation
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#element-vocab-group-animation">Animation.class</a>*
+&lt;/animation&gt;
+</pre></div>
+</td></tr></tbody></table><p>To the extent that time semantics apply to the content of the
+<code>animation</code> element, the implied time interval of this element is
+defined to be coterminous with the <a href="#terms-root-temporal-extent">root temporal extent</a>.</p></div><div class="div3">
+<h4><a id="animation-vocabulary-set"></a>13.1.3 set</h4><p>The <code>set</code> element expresses one or more a discrete changes (animations) to be applied (targeted) to style property attributes
+of associated elements.</p><p>A <code>set</code> element may appear as either (1) a child of a
+<a href="#terms-content-element">content element</a> or a <a href="#layout-vocabulary-region"><code>region</code></a> element,
+referred to as <a href="#terms-inline-animation">inline animation</a>, or
+(2) a child of an <a href="#animation-vocabulary-animation">animation</a> element, referred to as
+<a href="#terms-out-of-line-animation">out-of-line animation</a>.
+In the former case, the parent of the <code>set</code> element is the associated element; in the latter
+case, any element that references the <code>set</code> element using an <code>animate</code> attribute is
+an associated element.</p><p>The <code>set</code> element accepts as its children zero or more
+elements in the <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group.</p><a id="elt-syntax-set"></a><table class="syntax"><caption>XML Representation – Element Information Item: set</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;set
+  <a href="#timing-attribute-begin">begin</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#timing-attribute-dur">dur</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end">end</a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  fill = <a href="#animation-value-fill">&lt;fill&gt;</a>
+  repeatCount = <a href="#animation-value-repeatCount">&lt;repeatCount&gt;</a>
+  <a href="#style-attribute-style">style</a> = IDREFS
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
+&lt;/set&gt;
+</pre></div>
+</td></tr></tbody></table><p>Style property attributes targeted by an <code>set</code> element are specified directly using
+attributes in the TT Style namespace or in a namespace that is not some TT namespace, where the single target animation (key) value
+adheres to the <a href="#animation-value-animationValueList">&lt;animationValueList&gt;</a> syntax, where each
+constituent <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> adheres to the syntax of the specified
+attribute, and where exactly one constituent <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> is specified.</p><p>If more than one constituent <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> is specified, then all
+constituents other than the first must be ignored for the purpose of presentation processing, and must be considered an error for the
+purpose of validation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>In contrast with <a href="#svg11">[SVG 1.1]</a>, §19.2.13, a single <code>set</code> element, as defined here, may be used to
+perform discrete animations on a set of targeted style property attributes instead of being limited to targeting a single style property attribute.
+In <a href="#svg11">[SVG 1.1]</a>, this would require the use of multiple <code>set</code> elements rather than a single <code>set</code> element.</p></div><p>Except for the constraints or variations enumerated below, the semantics of the <code>set</code> element and its attributes
+enumerated above are defined to be those specified by <a href="#svg11">[SVG 1.1]</a>, §19.2.13:</p><ol class="enumar"><li><p>The attributes targeted by a <code>set</code> element and the discrete values to be applied to these attributes are
+specified by direct use of attributes in the TT Style namespace or in a namespace that is not a TT namespace (as opposed to using SVG's
+<code>attributeName</code> and <code>to</code> attributes).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>For example, specifying <code>tts:color="red"</code> is
+considered equivalent to specifying <code>attributeName="tts:color"</code> and <code>to="red"</code> in <a href="#svg11">[SVG 1.1]</a>.</p></div></li><li><p>If no <code>fill</code> attribute is specified, then a <em>fill</em> value of <code>remove</code> applies.</p></li></ol><p>An example of using the <code>set</code> element to animate content
+styling is illustrated below:</p><a id="animation-vocabulary-set-example-1"></a><table class="example"><caption>Example Fragment – Content Style Animation</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;p dur="5s" tts:color="yellow"&gt;
+<span class="strong">&lt;set begin="1s" dur="1s" tts:color="red"/&gt;</span>
+<span class="strong">&lt;set begin="2s" dur="1s" tts:color="green"/&gt;</span>
+<span class="strong">&lt;set begin="3s" dur="1s" tts:color="red"/&gt;</span>
+Text with Flashing Colors!
+&lt;/p&gt;
+...
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the foreground color of the content "Text
+with Flashing Colors!" is animated from yellow, to red, to green, to
+red, then back to yellow over a 5 second period.</p></div><p>An example of using the <code>set</code> element to animate region
+styling is illustrated below:</p><a id="animation-vocabulary-set-example-2"></a><table class="example"><caption>Example Fragment – Region Style Animation</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="" xmlns="http://www.w3.org/ns/ttml"
+    xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
+    xmlns:tts="http://www.w3.org/ns/ttml#styling"
+    ttp:cellResolution="40 16"&gt;
+    &lt;head&gt;
+      &lt;layout&gt;
+	&lt;region xml:id="r1" timeContainer="seq"&gt;
+	  <span class="strong">&lt;set dur="10s" tts:origin=" 8c 14c"/&gt;</span>
+	  <span class="strong">&lt;set dur="2s"  tts:origin=" 2c  2c"/&gt;</span>
+	  <span class="strong">&lt;set dur="3s"  tts:origin=" 8c 14c"/&gt;</span>
+	  <span class="strong">&lt;set dur="2s"  tts:origin="14c  4c"/&gt;</span>
+	  <span class="strong">&lt;set dur="10s" tts:origin=" 8c 14c"/&gt;</span>
+	  &lt;style tts:extent="24c 2c"/&gt;
+	&lt;/region&gt;
+      &lt;/layout&gt;
+    &lt;/head&gt;
+    &lt;body region="r1"&gt;...&lt;/body&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, the <a href="#terms-root-container-region">root container region</a> is divided into a
+cell grid of 40 columns and 16 rows. A region, <code>r1</code>, with
+dimensions of 24 columns and 2 rows is then positioned within the
+<a href="#terms-root-container-region">root container region</a>, with its position varying over time in order to
+create an effect of moving the region, which may be desirable so as
+to avoid obscuring characters in an underlying video with captions.</p></div><p></p><table border="1" class="ednote" summary="Editorial note: Set Example Images"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Set Example Images</b></td><td align="right" valign="top">2013-08-25</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Insert animated SVG images of set examples.</td></tr></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The semantics of the <code>set</code> element
+are based upon that defined by <a href="#svg11">[SVG 1.1]</a>,
+§19.2.13, which, in turn, is based upon <a href="#smil3">[SMIL 3.0]</a>, §12.</p></div></div></div><div class="div2">
+<h3><a id="animation-attribute-vocabulary"></a>13.2 Animation Attribute Vocabulary</h3><p>This section defines the <a href="#animation-attribute-animate"><b>13.2.1 animate</b></a> attribute used with <a href="#terms-content-element">content elements</a>
+and certain layout elements.</p><div class="div3">
+<h4><a id="animation-attribute-animate"></a>13.2.1 animate</h4><p>The <code>animate</code> attribute is used
+to reference one or more <a href="#animation-vocabulary-animate"><code>animate</code></a>
+or <a href="#animation-vocabulary-set"><code>set</code></a> elements
+each of which defines a specific <a href="#terms-out-of-line-animation">out-of-line animation</a>.</p><p>The <code>animate</code> attribute may be specified by an instance of the following
+element types:</p><ul><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li></ul><p>If specified, the value of an <code>animate</code> attribute must
+adhere to the <code>IDREFS</code> data type defined by <a href="#xsd-2">[XML Schema Part 2]</a>,
+§ 3.3.10, and, furthermore, each IDREF must reference an <a href="#animation-vocabulary-animate"><code>animate</code></a>
+or <a href="#animation-vocabulary-set"><code>set</code></a> element
+which has a <a href="#animation-vocabulary-animation"><code>animation</code></a> element as an ancestor.</p><p>A given IDREF must not appear more than one time in the value of an <code>animate</code>
+attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See the specific element type definitions that permit use of the
+<code>animate</code> attribute.</p></div></div></div><div class="div2">
+<h3><a id="animation-value-expressions"></a>13.3 Animation Value Expressions</h3><p>Animation attribute values include the use of the following expressions:</p><ul><li><p><a href="#animation-value-animationValue"><b>13.3.1 &lt;animationValue&gt;</b></a></p></li><li><p><a href="#animation-value-animationValueList"><b>13.3.2 &lt;animationValueList&gt;</b></a></p></li><li><p><a href="#animation-value-calcMode"><b>13.3.3 &lt;calcMode&gt;</b></a></p></li><li><p><a href="#animation-value-fill"><b>13.3.4 &lt;fill&gt;</b></a></p></li><li><p><a href="#animation-value-keySplines"><b>13.3.5 &lt;keySplines&gt;</b></a></p></li><li><p><a href="#animation-value-keyTimes"><b>13.3.6 &lt;keyTimes&gt;</b></a></p></li><li><p><a href="#animation-value-repeatCount"><b>13.3.7 &lt;repeatCount&gt;</b></a></p></li></ul><div class="div3">
+<h4><a id="animation-value-animationValue"></a>13.3.1 &lt;animationValue&gt;</h4><p>An &lt;animationValue&gt; expression is used to specify the starting (initial), intermediate,
+or ending (final) of the attribute targeted by the animation.</p><a id="animationValue-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;animationValue&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;animationValue&gt;
+  : string
+</pre></div>
+</td></tr></tbody></table><p>The syntax of an &lt;animationValue&gt; expression must satisfy all syntax
+requirements that apply to the attribute targeted by the animation.</p><table border="1" class="ednote" summary="Editorial note: Improve Syntax of AnimationValue"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Improve Syntax of AnimationValue</b></td><td align="right" valign="top">2014-07-31</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Enhance detail of syntax of &lt;animationValue&gt; in order to prevent appearance of an unquoted or unescaped semicolon,
+which is used as a delimiter between animation values in &lt;animationValueList&gt;.</td></tr></table><p>The semantics of an &lt;animationValue&gt; expression are those defined by
+<a href="#svg11">[SVG 1.1]</a>, §19.2.9.</p></div><div class="div3">
+<h4><a id="animation-value-animationValueList"></a>13.3.2 &lt;animationValueList&gt;</h4><p>An &lt;animationValueList&gt; expression is used to specify a list of animation values that sequentially
+apply to the attribute targeted by the animation, wherein each pair of values is separated by a SEMICOLON (U+003B) character
+optionally surrounded by linear white-space (LWSP) characters.</p><a id="animationValueList-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;animationValueList&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;animationValueList&gt;
+  : <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> [ ";" <a href="#animation-value-animationValue">&lt;animationValue&gt;</a> ]*
+</pre></div>
+</td></tr></tbody></table><p>The syntax of an &lt;animationValue&gt; in an &lt;animationValueList&gt; expression must satisfy all syntax
+requirements that apply to the attribute targeted by the animation.</p><p>The semantics of an &lt;animationValueList&gt; expression are those defined by
+<a href="#svg11">[SVG 1.1]</a>, §19.2.9.</p></div><div class="div3">
+<h4><a id="animation-value-calcMode"></a>13.3.3 &lt;calcMode&gt;</h4><p>A &lt;calcMode&gt; expression is used to control the interpolation mode of the animation.</p><a id="calcMode-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;calcMode&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;calcMode&gt;
+  : "discrete"
+  | "linear"
+  | "spline"
+</pre></div>
+</td></tr></tbody></table><p>The semantics of a &lt;calcMode&gt; expression are those defined by
+<a href="#svg11">[SVG 1.1]</a>, §19.2.9.</p></div><div class="div3">
+<h4><a id="animation-value-fill"></a>13.3.4 &lt;fill&gt;</h4><p>A &lt;fill&gt; expression is used to determine effect of the animation after the active end of the animation.</p><a id="fill-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;fill&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;fill&gt;
+  : "freeze"
+  | "remove"
+</pre></div>
+</td></tr></tbody></table><p>The semantics of a &lt;fill&gt; expression are those defined by
+<a href="#svg11">[SVG 1.1]</a>, §19.2.8.</p></div><div class="div3">
+<h4><a id="animation-value-keySplines"></a>13.3.5 &lt;keySplines&gt;</h4><p>An &lt;keySplines&gt; expression is used to specify a list of Bezier control points that control the pacing of an
+animation, wherein each pair of values is separated by a SEMICOLON (U+003B) character
+optionally surrounded by linear white-space (LWSP) characters.</p><a id="keySplines-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;keySplines&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;keySplines&gt;
+  : control [ lwsp? ";" lwsp? control ]*
+
+control
+  : x1 comma? y1 comma? x2 comma? y2
+
+x1, x2, y1, y2
+  : coordinate
+
+coordinate                                // 0 ≥ <em>value</em> ≥ 1
+  : whole
+  | whole "." fraction
+  | "." fraction
+
+whole, fraction
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+
+comma
+  : ","
+
+lwsp
+  : ( ' ' | '\t' | '\n' | '\r' )+
+</pre></div>
+</td></tr></tbody></table><p>The semantics of a &lt;keySplines&gt; expression are those defined by
+<a href="#svg11">[SVG 1.1]</a>, §19.2.9, as apply to the <code>keySplines</code> attribute.</p></div><div class="div3">
+<h4><a id="animation-value-keyTimes"></a>13.3.6 &lt;keyTimes&gt;</h4><p>An &lt;keyTimes&gt; expression is used to specify a list of relative time values that control the pacing of an
+animation, wherein each pair of values is separated by a SEMICOLON (U+003B) character
+optionally surrounded by linear white-space (LWSP) characters.</p><a id="keyTimes-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;keyTimes&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;keyTimes&gt;
+  : time [ lwsp? ";" lwsp? time ]*
+
+time                                // 0 ≥ <em>value</em> ≥ 1
+  : whole
+  | whole "." fraction
+  | "." fraction
+
+whole, fraction
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+
+
+lwsp
+  : ( ' ' | '\t' | '\n' | '\r' )+
+</pre></div>
+</td></tr></tbody></table><p>The semantics of a &lt;keyTimes&gt; expression are those defined by
+<a href="#svg11">[SVG 1.1]</a>, §19.2.9, as apply to the <code>keyTimes</code> attribute.</p></div><div class="div3">
+<h4><a id="animation-value-repeatCount"></a>13.3.7 &lt;repeatCount&gt;</h4><p>A &lt;repeatCount&gt; expression is used to determine the number of iterations of a repeated animation.</p><a id="repeatCount-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;repeatCount&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;repeatCount&gt;
+  : count
+  | "indefinite"
+
+count:
+  : <a href="#style-value-digit">&lt;digit&gt;</a>+                       // <em>value</em> &gt; 0
+</pre></div>
+</td></tr></tbody></table><p>The semantics of a &lt;repeatCount&gt; expression are those defined by
+<a href="#svg11">[SVG 1.1]</a>, §19.2.8.</p></div></div></div><div class="div1">
+<h2><a id="metadata"></a>14 Metadata</h2><p>This section specifies the <em>metadata</em> matter of the core
+vocabulary catalog, where
+metadata is to be understood as a separable layer of information that applies to
+parameters, content,
+style, layout, timing, and even metadata itself, where the information
+represented by metadata takes one of two forms: (1) metadata defined by this
+specification for standardized use in a <a href="#terms-document-instance">document instance</a>, and (2) arbitrary
+metadata defined outside of the scope of this specification, whose use and
+semantics depend entirely upon an application's use of TTML Content.</p><div class="div2">
+<h3><a id="metadata-element-vocabulary"></a>14.1 Metadata Element Vocabulary</h3><p>The <a href="#metadata-vocabulary-metadata"><b>14.1.1 metadata</b></a> element serves as
+a generic container element for grouping metadata information.</p><p>In addition, the following elements, all defined in the TT Metadata Namespace,
+provide standard representations for metadata that is expected to be commonly
+used in a <a href="#terms-document-instance">document instance</a>:
+</p><ul><li><p><a href="#metadata-vocabulary-actor"><b>14.1.2 ttm:actor</b></a></p></li><li><p><a href="#metadata-vocabulary-agent"><b>14.1.3 ttm:agent</b></a></p></li><li><p><a href="#metadata-vocabulary-copyright"><b>14.1.4 ttm:copyright</b></a></p></li><li><p><a href="#metadata-vocabulary-desc"><b>14.1.5 ttm:desc</b></a></p></li><li><p><a href="#metadata-vocabulary-item"><b>14.1.6 ttm:item</b></a></p></li><li><p><a href="#metadata-vocabulary-name"><b>14.1.7 ttm:name</b></a></p></li><li><p><a href="#metadata-vocabulary-title"><b>14.1.8 ttm:title</b></a></p></li></ul><div class="div3">
+<h4><a id="metadata-vocabulary-metadata"></a>14.1.1 metadata</h4><p>The <code>metadata</code> element functions as a generic container for metadata
+information.</p><p>Metadata information may be expressed with a <code>metadata</code> element by specifying
+(1) one or more metadata attributes or foreign namespace attributes on the <code>metadata</code> element,
+(2) one or more metadata item or foreign namespace child elements,
+(3) one or more <a href="#embedded-content-vocabulary-data"><code>data</code></a> child elements, or
+(4) a combination of the preceding.</p><a id="elt-syntax-metadata"></a><table class="syntax"><caption>XML Representation – Element Information Item: metadata</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;metadata
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute in TT Metadata namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> (<a href="#element-vocab-group-data"><code>Data.class</code></a>|{<em>any element in TT Metadata namespace</em>}|{<em>any element not in any TT namespace</em>})*
+&lt;/metadata&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The meaning of a specific metadata item must be evaluated in the
+context where it appears. The core vocabulary catalog permits an
+arbitrary number of <code>metadata</code> element children on any
+<a href="#terms-content-element">content element</a> type. See specific element
+vocabulary definitions for any constraints that apply to such
+usage.</p></div><p>The use of document metadata is illustrated by the following example.</p><a id="metadata-vocabulary-metadata-example-1"></a><table class="example"><caption>Example Fragment – Document Metadata</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;head&gt;
+  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+    &lt;ttm:title&gt;Document Metadata Example&lt;/ttm:title&gt;
+    &lt;ttm:desc&gt;This document employs document metadata.&lt;/ttm:desc&gt;
+  &lt;/metadata&gt;
+&lt;/head&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p><p>The use of element metadata is illustrated by the following example.</p><a id="metadata-vocabulary-metadata-example-2"></a><table class="example"><caption>Example Fragment – Element Metadata</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;div&gt;
+  &lt;metadata xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+    &lt;ttm:title&gt;Chapter 6 – Sherlock Holmes Gives a Demonstration&lt;/ttm:title&gt;
+    &lt;ttm:desc&gt;Holmes shows Watson how the murderer entered the window.&lt;/ttm:desc&gt;
+  &lt;/metadata&gt;
+&lt;/div&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p><p>The use of metadata attribute items is illustrated by the following example.</p><a id="metadata-vocabulary-metadata-example-3"></a><table class="example"><caption>Example Fragment – Foreign Metadata Attribute Items</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;div xmlns:ext="http://example.org/ttml#metadata"&gt;
+  &lt;metadata ext:ednote="remove this division prior to publishing"/&gt;
+&lt;/div&gt;
+...
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, a global attribute from a foreign (external)
+namespace is used to express a metadata attribute that applies
+semantically to the containing <code>div</code> element. Note that the
+attribute may also be expressed directly on the <code>div</code> element;
+however, in this case the author wishes to segregate certain metadata
+attributes by expressing them indirectly on <code>metadata</code>
+elements.</p></div><p></p><p>The use of foreign element metadata is illustrated by the following example.</p><a id="metadata-vocabulary-metadata-example-4"></a><table class="example"><caption>Example Fragment – Foreign Element Metadata</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;metadata
+  xmlns:dc="http://purl.org/dc/elements/1.1/"
+  xmlns:dcterms="http://purl.org/dc/terms/"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"&gt;
+  &lt;dc:title&gt;Foreign Element Metadata Example&lt;/dc:title&gt;
+  &lt;dc:description&gt;Express metadata using elements in foreign namespace.&lt;/dc:description&gt;
+  &lt;dc:format xsi:type="dcterms:IMT"&gt;application/ttml+xml&lt;/dc:format&gt;
+&lt;/metadata&gt;
+...
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, a number of elements defined by the Dublin
+Core metadata vocabulary are used to express document level metadata.</p></div><p></p></div><div class="div3">
+<h4><a id="metadata-vocabulary-actor"></a>14.1.2 ttm:actor</h4><p>The <code>ttm:actor</code> element is used to link the definition of a (role-based) character
+agent with another agent that portrays the character.</p><a id="elt-syntax-metadata-actor"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:actor</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttm:actor
+  <span class="reqattr">agent</span> = IDREF
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> EMPTY
+&lt;/ttm:actor&gt;
+</pre></div>
+</td></tr></tbody></table><p>The <code>agent</code> attribute of a <code>ttm:actor</code> element must
+reference a <em>significant</em> <code>ttm:agent</code> element that denotes the agent
+acting the part of a character.</p><p>An example of the <code>ttm:actor</code> element is shown above in
+<a href="#metadata-vocabulary-agent-example-1"><b>Example Fragment – Agent Metadata</b></a>.</p></div><div class="div3">
+<h4><a id="metadata-vocabulary-agent"></a>14.1.3 ttm:agent</h4><p>The <code>ttm:agent</code> element is used to define an agent for the purpose of associating
+content information with an agent who is involved in the production or expression of that content.</p><p>The <code>ttm:agent</code> element accepts as its children zero or more <code>ttm:name</code> elements followed by
+zero or one <code>ttm:actor</code> element.</p><p>At least one <code>ttm:name</code> element child should be specified that expresses a name for the
+agent, whether it be the name of a person, character, group, or organization.</p><a id="elt-syntax-metadata-agent"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:agent</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttm:agent
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <span class="reqattr">type</span> = (<em>person</em>|<em>character</em>|<em>group</em>|<em>organization</em>|<em>other</em>)
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#metadata-vocabulary-name">ttm:name</a>*, <a href="#metadata-vocabulary-actor">ttm:actor</a>?
+&lt;/ttm:agent&gt;
+</pre></div>
+</td></tr></tbody></table><p>A <code>type</code> attribute must be specified on each <code>ttm:agent</code> element, and,
+if specified, must have one of the following values:</p><ul><li><p><code>person</code></p></li><li><p><code>character</code></p></li><li><p><code>group</code></p></li><li><p><code>organization</code></p></li><li><p><code>other</code></p></li></ul><p>If the value of the <code>type</code> attribute is <code>character</code>, then the
+<code>ttm:agent</code> element instance should specify a <code>ttm:actor</code> child that
+specifies the agent that plays the role of the actor.</p><p>A <code>ttm:agent</code> metadata item is considered to be significant only
+when specified as a child of the <code>head</code> element or as a child of a
+<code>metadata</code> element child of the <code>head</code> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A <code>ttm:agent</code> element instance is typically referenced using a <code>ttm:agent</code>
+attribute on a <a href="#terms-content-element">content element</a> type.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>If a character agent is played by multiple actors, then multiple character
+agents may be specified (and referenced) wherein different definitions of the
+character specify different actors.</p></div><p>The use of agent metadata is illustrated by the following example.</p><a id="metadata-vocabulary-agent-example-1"></a><table class="example"><caption>Example Fragment – Agent Metadata</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;tt xml:lang="en" xmlns="http://www.w3.org/ns/ttml" xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;
+  &lt;head&gt;
+    <span class="strong">&lt;ttm:agent xml:id="connery" type="person"&gt;</span>
+      &lt;ttm:name type="family"&gt;Connery&lt;/ttm:name&gt;
+      &lt;ttm:name type="given"&gt;Thomas Sean&lt;/ttm:name&gt;
+      &lt;ttm:name type="alias"&gt;Sean&lt;/ttm:name&gt;
+      &lt;ttm:name type="full"&gt;Sir Thomas Sean Connery&lt;/ttm:name&gt;
+    <span class="strong">&lt;/ttm:agent&gt;</span>
+    <span class="strong">&lt;ttm:agent xml:id="bond" type="character"&gt;</span>
+      &lt;ttm:name type="family"&gt;Bond&lt;/ttm:name&gt;
+      &lt;ttm:name type="given"&gt;James&lt;/ttm:name&gt;
+      &lt;ttm:name type="alias"&gt;007&lt;/ttm:name&gt;
+      &lt;ttm:actor agent="connery"/&gt;
+    <span class="strong">&lt;/ttm:agent&gt;</span>
+  &lt;/head&gt;
+  &lt;body&gt;
+    &lt;div&gt;
+      ...  
+      &lt;p <span class="strong">ttm:agent="bond"</span>&gt;I travel, a sort of licensed troubleshooter.&lt;/p&gt;
+      ...  
+    &lt;/div&gt;
+  &lt;/body&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>In the above example, two agents, a real (person) agent, Sean
+Connery, and a fictitious (character) agent, James Bond, are defined,
+where the latter is linked to the former by means of the a
+<code>ttm:actor</code> element. A reference is then made from content (the
+<code>p</code> element) to the character agent associated with
+(responsible for producing) that content. Note that in this example
+the <code>ttm:agent</code> metadata items are specified as immediate
+children of the document's <code>head</code> element rather than being
+placed in a container <code>metadata</code> element.</p></div></div><div class="div3">
+<h4><a id="metadata-vocabulary-copyright"></a>14.1.4 ttm:copyright</h4><p>The <code>ttm:copyright</code> element is used to express a human-readable copyright that
+applies to some scoping level.</p><p>A copyright statement that applies to a document as a whole should appear as a
+child of the <code>head</code> element.</p><a id="elt-syntax-metadata-copyright"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:copyright</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttm:copyright
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA
+&lt;/ttm:copyright&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>No specific use of the <code>ttm:copyright</code> element is defined by this specification.</p></div></div><div class="div3">
+<h4><a id="metadata-vocabulary-desc"></a>14.1.5 ttm:desc</h4><p>The <code>ttm:desc</code> element is used to express a human-readable description of
+a specific element instance.</p><a id="elt-syntax-metadata-desc"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:desc</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttm:desc
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA
+&lt;/ttm:desc&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>No specific use of the <code>ttm:desc</code> element is defined by this specification.</p></div><p>Examples of the <code>ttm:desc</code> element are shown above in
+<a href="#metadata-vocabulary-metadata-example-1"><b>Example Fragment – Document Metadata</b></a> and
+<a href="#metadata-vocabulary-metadata-example-2"><b>Example Fragment – Element Metadata</b></a>.</p></div><div class="div3">
+<h4><a id="metadata-vocabulary-item"></a>14.1.6 ttm:item</h4><p>The <code>ttm:item</code> element is used to express arbitrary named metadata items.</p><p>The <code>ttm:item</code> element accepts one of the following two content models:
+(1) one or more text nodes (i.e., <code>#PCDATA</code>) or
+(2) zero or more nested <a href="#metadata-vocabulary-item">ttm:item</a> elements.</p><a id="elt-syntax-metadata-item"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:item</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttm:item
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <span class="reqattr">name</span> = <a href="#metadata-value-item-name">&lt;item-name&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA | <a href="#metadata-vocabulary-item">ttm:item</a>*
+&lt;/ttm:item&gt;
+</pre></div>
+</td></tr></tbody></table><p>A <code>name</code> attribute must be specified to identify the name of the item, the value of which must adhere to
+an <a href="#metadata-value-item-name">&lt;item-name&gt;</a> value expression.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>No general constraint is placed on the appearance of multiple named metadata items that specify the same name; however,
+the definition of a specific named item may further constrain the context of use as well as the potential appearance of multiple items that share the same name.</p></div><p>The value of a named metadata item is
+(1) empty if the element has no child text or element nodes,
+(2) the character content of the <code>ttm:item</code> element when that element's children consists solely of text nodes, or
+(3) a collection of named metadata sub-items.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The definition of a particular named item will typically constrain the set of permitted values. Furthermore, it may
+specify that a particular value is implied in the absence of a specified value.</p></div><p>The use of a named metadata item is illustrated by the following example, which shows the use of a named metadata item
+in order to associate a <a href="#terms-simple-data-embedding">simple data embedding</a> with an original file name.</p><a id="metadata-vocabulary-item-example-1"></a><table class="example"><caption>Example Fragment – Named Metadata Item</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+...
+&lt;image&gt;
+  &lt;source&gt;
+    &lt;data type="image/png"&gt;
+      <span class="strong">&lt;ttm:item name="originalFileName" xmlns:ttm="http://www.w3.org/ns/ttml#metadata"&gt;image.png&lt;/ttm:item&gt;</span>
+      &lt;chunk length="119"&gt;
+        iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8
+        YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=
+      &lt;/chunk&gt;
+    &lt;/data&gt;
+  &lt;/source&gt;
+&lt;/image&gt;
+...
+</pre></div>
+</td></tr></tbody></table><p></p><div class="note"><p class="prefix"><b>Note:</b></p><p>The above example makes use of a single <a href="#embedded-content-vocabulary-chunk">chunk</a> element in order
+to include a <code>ttm:item</code> element as a child of the <a href="#embedded-content-vocabulary-data">data</a> element;
+i.e., if the encoded image bytes had been included directly as #PCDATA in the <a href="#embedded-content-vocabulary-data">data</a> element,
+then it would not have been possible to include the <code>ttm:item</code> child element. See the supported content models on the
+<a href="#embedded-content-vocabulary-data">data</a> element for more information.</p></div></div><div class="div3">
+<h4><a id="metadata-vocabulary-name"></a>14.1.7 ttm:name</h4><p>The <code>ttm:name</code> element is used to specify a name of a person, character,
+group, or organization.</p><a id="elt-syntax-metadata-name"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:name</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttm:name
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <span class="reqattr">type</span> = (<em>full</em>|<em>family</em>|<em>given</em>|<em>alias</em>|<em>other</em>)
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA
+&lt;/ttm:name&gt;
+</pre></div>
+</td></tr></tbody></table><p>A <code>type</code> attribute must be specified on each <code>ttm:name</code> element, and,
+if specified, must have one of the following values:</p><ul><li><p><code>full</code></p></li><li><p><code>family</code></p></li><li><p><code>given</code></p></li><li><p><code>alias</code></p></li><li><p><code>other</code></p></li></ul><p>The relationship between the type of a name and the syntactic expression of the name
+is not defined by this specification.</p><p>Two examples of the <code>ttm:name</code> element are shown above in
+<a href="#metadata-vocabulary-agent-example-1"><b>Example Fragment – Agent Metadata</b></a>.</p></div><div class="div3">
+<h4><a id="metadata-vocabulary-title"></a>14.1.8 ttm:title</h4><p>The <code>ttm:title</code> element is used to express a human-readable title of
+a specific element instance.</p><a id="elt-syntax-metadata-title"></a><table class="syntax"><caption>XML Representation – Element Information Item: ttm:title</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;ttm:title
+  <a href="#content-attribute-condition">condition</a> = <a href="#content-value-condition">&lt;condition&gt;</a>
+  <a href="#content-attribute-xml-id">xml:id</a> = ID
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-space">xml:space</a> = (<em>default</em>|<em>preserve</em>)
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> #PCDATA
+&lt;/ttm:title&gt;
+</pre></div>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>No specific use of the <code>ttm:title</code> element is defined by this specification.</p></div><p>Examples of the <code>ttm:title</code> element are shown above in
+<a href="#metadata-vocabulary-metadata-example-1"><b>Example Fragment – Document Metadata</b></a> and
+<a href="#metadata-vocabulary-metadata-example-2"><b>Example Fragment – Element Metadata</b></a>.</p></div></div><div class="div2">
+<h3><a id="metadata-attribute-vocabulary"></a>14.2 Metadata Attribute Vocabulary</h3><p>This section specifies the following attributes in the TT Metadata Namespace
+for use with the <code>metadata</code> element and with certain
+<a href="#terms-content-element">content element</a> types:</p><ul><li><p><a href="#metadata-attribute-agent"><b>14.2.1 ttm:agent</b></a></p></li><li><p><a href="#metadata-attribute-role"><b>14.2.2 ttm:role</b></a></p></li></ul><div class="issue"><p class="prefix"><a id="issue-358"></a><b>Issue (issue-358):</b></p><p class="prefix"><b>Document Sequencing</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/358">http://www.w3.org/AudioVideo/TT/tracker/issues/358</a></p><p>Add <code>ttm:sequenceIdentifier</code> or <code>ttm:sequenceNumber</code> or both if unavoidable.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><div class="issue"><p class="prefix"><a id="issue-361"></a><b>Issue (issue-361):</b></p><p class="prefix"><b>Media Timestamp Correlation</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/361">http://www.w3.org/AudioVideo/TT/tracker/issues/361</a></p><p>Add <code>ttm:mediaTimestamp</code> to support media synchronization.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Only certain metadata item attributes may be used with <a href="#terms-content-element">content element</a>. See
+the definitions of <a href="#terms-content-element">content elements</a> to determine permissible usage.</p></div><div class="div3">
+<h4><a id="metadata-attribute-agent"></a>14.2.1 ttm:agent</h4><p>The <code>ttm:agent</code> attribute takes an <code>IDREFS</code>
+value, and is used with certain <a href="#terms-content-element">content elements</a> to designate the
+agents that perform or are
+involved in the performance of the content.</p><p>If specified, a <code>ttm:agent</code> attribute must reference <em>significant</em>
+<code>ttm:agent</code> element instances.</p><p>The same IDREF, <em>ID</em>, should not appear more than once in the value of a <code>ttm:agent</code> attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This constraint is intended to discourage the use of redundant agent references.</p></div><p>An example of the <code>ttm:agent</code> attribute is shown above in
+<a href="#metadata-vocabulary-agent-example-1"><b>Example Fragment – Agent Metadata</b></a>.</p></div><div class="div3">
+<h4><a id="metadata-attribute-role"></a>14.2.2 ttm:role</h4><p>The <code>ttm:role</code> attribute may be used by a content author
+to express
+the roles, functions, or characteristics
+of some <a href="#terms-content-element">content element</a> that is so labeled.</p><div class="issue"><p class="prefix"><a id="issue-25"></a><b>Issue (issue-25):</b></p><p class="prefix"><b>Parameterized Roles</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/25">http://www.w3.org/AudioVideo/TT/tracker/issues/25</a></p><p>Consider supporting parameterized roles to increase CEA 708 interoperability.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If specified, the value of this attribute must adhere to the following
+syntax, where
+the syntactic element <em>S</em> must adhere to production
+[3] <code>S</code> as defined by <a href="#xml10">[XML 1.0]</a>&nbsp;§
+2.3:</p><a id="metadata-attribute-role-syntax"></a><table class="syntax"><caption>Syntax Representation – ttm:role</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+ttm:role
+  role ( <em>S</em> role )*
+
+role
+  : "action"
+  | "caption"
+  | "description"
+  | "dialog"
+  | "expletive"
+  | "kinesic"
+  | "lyrics"
+  | "music"
+  | "narration"
+  | "quality"
+  | "sound"
+  | "source"
+  | "suppressed"
+  | "reproduction"
+  | "thought"
+  | "title"
+  | "transcription"
+  | extension-role
+
+extension-role
+  : "x-" token-char+
+
+token-char
+  : { XML NameChar }    // XML 1.1 Production [4a]
+</pre></div>
+</td></tr></tbody></table><p>The same <code>role</code> token, <em>R</em>, should not appear more than once in the value of a <code>ttm:role</code> attribute.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This constraint is intended to discourage the use of redundant role tokens.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>All values of <code>ttm:role</code> that do not start with the prefix
+<code>x-</code> are reserved for future standardization.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>If using a custom <code>x-</code> prefixed form of <code>ttm:role</code>, it
+is recommended that an organization unique infix be used as well in order to
+prevent collisions. For example, <code>x-example-org-custom-role</code>. Furthermore,
+a registry for role values is available at
+<a href="http://www.w3.org/wiki/TTML/RoleRegistry">http://www.w3.org/wiki/TTML/RoleRegistry</a>
+in order to promote interoperability and collision avoidance.</p></div></div></div><div class="div2">
+<h3><a id="metadata-value-expressions"></a>14.3 Metadata Value Expressions</h3><p>Metadata vocabulary may make use of the following expressions:</p><ul><li><p><a href="#metadata-value-item-name"><b>14.3.1 &lt;item-name&gt;</b></a></p></li></ul><div class="div3">
+<h4><a id="metadata-value-item-name"></a>14.3.1 &lt;item-name&gt;</h4><p>An &lt;item-name&gt; expression is used to specify the name of a metadata item expressed with a
+<a href="#metadata-vocabulary-item">ttm:item</a> element.</p><a id="item-name-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;item-name&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;item-name&gt;
+  : <a href="#metadata-value-named-item">&lt;named-item&gt;</a>
+  | <a href="http://www.w3.org/TR/xmlschema-2/#QName">xsd:QName</a>
+</pre></div>
+</td></tr></tbody></table><p>If an item name expression takes the form of a qualified name (<a href="http://www.w3.org/TR/xmlschema-2/#QName">xsd:QName</a>), 
+then the prefix of that qualified name must have been declared in a namespace declaration as specified by <a href="#xmlns10">[XML Namespaces 1.0]</a>.</p><p>All values of &lt;item-name&gt; that do not take the form of qualified name (<a href="http://www.w3.org/TR/xmlschema-2/#QName">xsd:QName</a>)
+are reserved for future standardization by the W3C.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>It is intended that all item names defined by this specification are unqualified (without a prefix), whereas those defined by
+external specifications are qualified (with a prefix).</p></div></div><div class="div3">
+<h4><a id="metadata-value-named-item"></a>14.3.2 &lt;named-item&gt;</h4><p>A &lt;named-item&gt; value is one of an enumerated collection of named metadata items associated with a value by
+a <a href="#metadata-vocabulary-item"><code>ttm:item</code></a> element.</p><a id="named-item-value-expression-syntax"></a><table class="syntax"><caption>Syntax Representation – &lt;named-item&gt;</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;named-item&gt;
+  : cea608CaptionService
+  | cea608Channel
+  | cea608ContentAdvisory
+  | cea608CopyAndRedistributionControl
+  | cea608FieldStart
+  | cea608ProgramName
+  | cea608ProgramType
+  | cea708EasyReader
+  | cea708FCCMinimum
+  | cea708ServiceNumber
+  | cea708TransformMode
+  | cea708TransformOrigin
+  | cea708TransformTimingThreshold
+  | creationCountryOfOrigin
+  | creationDate
+  | creationSystem
+  | editor
+  | editorContact
+  | maximumCharactersPerRow
+  | originalEpisodeTitle
+  | originalFileName
+  | originalProgramTitle
+  | publisher
+  | readingSpeed
+  | revisionDate
+  | revisionNumber
+  | sourceFormat
+  | subtitleCount
+  | subtitleReferenceCode
+  | targetAspectRatio
+  | targetActiveFormatDescriptor
+  | targetBarData
+  | targetFormat
+  | translatedEpisodeTitle
+  | translatedProgramTitle
+  | translator
+  | translatorContact
+</pre></div>
+</td></tr></tbody></table><p></p><div class="issue"><p class="prefix"><a id="issue-328"></a><b>Issue (issue-328):</b></p><p class="prefix"><b>Alternate Text Metadata</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/328">http://www.w3.org/AudioVideo/TT/tracker/issues/328</a></p><p>Add named item to handle <code>ittm:altText</code>.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><table border="1" class="ednote" summary="Editorial note: Elaborate Named Items"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Elaborate Named Items</b></td><td align="right" valign="top">2014-11-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Further specify the value syntax of certain named items, e.g., by adding external document references (CEA608) or by defining specific value syntax.</td></tr></table><dl><dt class="label"><a id="named-item-cea608CaptionService"></a><code>cea608CaptionService</code></dt><dd><p>A string that expresses the field and channel mapping of a CEA-608 caption service, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608Channel"></a><code>cea608Channel</code></dt><dd><p>A string that expresses the channel code of a CEA-608 caption service, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608ContentAdvisory"></a><code>cea608ContentAdvisory</code></dt><dd><p>A string that expresses the content advisory packet information of a CEA-608 caption service, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608CopyAndRedistributionControl"></a><code>cea608CopyAndRedistributionControl</code></dt><dd><p>A string that expresses the copy and redistribution control packet information of a CEA-608 caption service, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608FieldStart"></a><code>cea608FieldStart</code></dt><dd><p>An integer that expresses the field start of a CEA-608 caption service, where the value
+is either 1 or 2.</p></dd><dt class="label"><a id="named-item-cea608ProgramName"></a><code>cea608ProgramName</code></dt><dd><p>A string that expresses the program name of a CEA-608 caption service, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea608ProgramType"></a><code>cea608ProgramType</code></dt><dd><p>A string that expresses the program type code of a CEA-608 caption service, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-cea708EasyReader"></a><code>cea708EasyReader</code></dt><dd><p>A boolean that expresses whether a CEA-708 caption service is characterized for use with an easy reader, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:boolean</a>.</p></dd><dt class="label"><a id="named-item-cea708FCCMinimum"></a><code>cea708FCCMinimum</code></dt><dd><p>A boolean that expresses whether a CEA-708 caption service is characterized as conforming to minimum FCC decoder requirements, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:boolean</a>.</p></dd><dt class="label"><a id="named-item-cea708ServiceNumber"></a><code>cea708ServiceNumber</code></dt><dd><p>An integer that expresses the service number of a CEA-708 caption service, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</a> and is less than 32.</p></dd><dt class="label"><a id="named-item-cea708TransformMode"></a><code>cea708TransformMode</code></dt><dd><p>One of the token values <code>enhanced</code> or <code>preserved</code>.</p></dd><dt class="label"><a id="named-item-cea708TransformOrigin"></a><code>cea708TransformOrigin</code></dt><dd><p>Either the token <code>none</code> or an <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>,
+where the latter expresses a CEA-708 transformation source format.</p></dd><dt class="label"><a id="named-item-cea708TransformTimingThreshold"></a><code>cea708TransformTimingThreshold</code></dt><dd><p>A real number that expresses a threshold parameter used to suppress the inclusion of temporary timed states when
+transforming amongst a CEA-708 caption service and a <a href="#terms-timed-text-content-document">timed text content document</a>,
+where the value adheres to <a href="http://www.w3.org/TR/xmlschema-2/#boolean">xsd:float</a>.</p></dd><dt class="label"><a id="named-item-creationCountryOfOrigin"></a><code>creationCountryOfOrigin</code></dt><dd><p>A string that expresses a the country or origin code associated with this document, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-creationDate"></a><code>creationDate</code></dt><dd><p>A date that expresses the creation date of this document, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#date">xsd:date</a>.</p></dd><dt class="label"><a id="named-item-creationSystem"></a><code>creationSystem</code></dt><dd><p>A free form string expressing the software and version used to create the document, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-editor"></a><code>editor</code></dt><dd><p>A string that expresses the name of one or more editors, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-editorContact"></a><code>editorContact</code></dt><dd><p>A string that expresses the contact details of one or more editors, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-maximumCharactersPerRow"></a><code>maximumCharactersPerRow</code></dt><dd><p>A non-negative integer that expresses the maximum number of characters per row (line) used in this document, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>.</p></dd><dt class="label"><a id="named-item-originalEpisodeTitle"></a><code>originalEpisodeTitle</code></dt><dd><p>A string that expresses the episode title in the original language, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-originalFileName"></a><code>originalFileName</code></dt><dd><p>A string that expresses the original file name of a <a href="#terms-data-resource">data resource</a>, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p><p>A <code>originalFileName</code> item may specified as a descendant element of a <a href="#embedded-content-vocabulary-data">data</a> element
+in order to associate the <a href="#terms-data-resource">data resource</a> represented by that <a href="#embedded-content-vocabulary-data">data</a> element
+with an original file name.</p></dd><dt class="label"><a id="named-item-originalProgramTitle"></a><code>originalProgramTitle</code></dt><dd><p>A string that expresses the program title in the original language, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-publisher"></a><code>publisher</code></dt><dd><p>A string that expresses the name of one or more publishers, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-readingSpeed"></a><code>readingSpeed</code></dt><dd><p>An integer that expresses the reading speed in words per minute, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</a>.</p></dd><dt class="label"><a id="named-item-revisionDate"></a><code>revisionDate</code></dt><dd><p>A date that expresses the last revision date of this document, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#date">xsd:date</a>.</p></dd><dt class="label"><a id="named-item-revisionNumber"></a><code>revisionNumber</code></dt><dd><p>A non-negative integer that expresses the revision number of this document, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>.</p></dd><dt class="label"><a id="named-item-sourceFormat"></a><code>sourceFormat</code></dt><dd><p>A string that expresses the source subtitle or caption format from which the <a href="#terms-enclosing-document-instance">enclosing document instance</a>
+was transformed, where the value adheres to either <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
+or <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>.</p></dd><dt class="label"><a id="named-item-subtitleCount"></a><code>subtitleCount</code></dt><dd><p>A non-negative integer that expresses the number of subtitles (captions) in this document, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>.</p></dd><dt class="label"><a id="named-item-subtitleReferenceCode"></a><code>subtitleReferenceCode</code></dt><dd><p>A string that expresses a subtitle reference code, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-targetAspectRatio"></a><code>targetAspectRatio</code></dt><dd><p>A string that expresses the target video's aspect ratio, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-targetActiveFormatDescriptor"></a><code>targetActiveFormatDescriptor</code></dt><dd><p>A string that expresses the target video's active format descriptor, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-targetBarData"></a><code>targetBarData</code></dt><dd><p>A string that expresses the target video's bar data, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-targetFormat"></a><code>targetFormat</code></dt><dd><p>A string that expresses the target subtitle or caption format to which the <a href="#terms-enclosing-document-instance">enclosing document instance</a>
+is intended to be transformed, where the value adheres to either <a href="http://www.w3.org/TR/xmlschema-2/#token">xsd:token</a>
+or <a href="http://www.w3.org/TR/xmlschema-2/#anyURI">xsd:anyURI</a>.</p></dd><dt class="label"><a id="named-item-translatedEpisodeTitle"></a><code>translatedEpisodeTitle</code></dt><dd><p>A string that expresses the episode title in the translated (local) language, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-translatedProgramTitle"></a><code>translatedProgramTitle</code></dt><dd><p>A string that expresses the program title in the translated (local) language, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-translator"></a><code>translator</code></dt><dd><p>A string that expresses the name of one or more translators, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd><dt class="label"><a id="named-item-translatorContact"></a><code>translatorContact</code></dt><dd><p>A string that expresses the contact details of one or more translators, where the value
+adheres to <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>.</p></dd></dl></div></div></div></div><div class="back"><div class="div1">
+<h2><a id="concrete-encoding"></a>A Concrete Encoding</h2><p><em>This appendix is normative.</em></p><p>In the absence of other requirements, a <a href="#terms-document-instance">document instance</a> should be concretely encoded as a
+well-formed XML 1.0 <a href="#xml10">[XML 1.0]</a> document using the UTF-8 character encoding.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>When using XML 1.0 <a href="#xml10">[XML 1.0]</a> as the concrete encoding of TTML, only the following named character entities are defined:
+<code>&amp;amp;</code>, <code>&amp;apos;</code>, <code>&amp;gt;</code>, <code>&amp;lt;</code>, and <code>&amp;quot;</code>.</p></div><div class="issue"><p class="prefix"><a id="issue-360"></a><b>Issue (issue-360):</b></p><p class="prefix"><b>Support Content Encoding</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/360">http://www.w3.org/AudioVideo/TT/tracker/issues/360</a></p><p>Specify preference to use of gzip content encoding for compressed delivery in the case that client indicates it accepts encoding.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div></div><div class="div1">
+<h2><a id="reduced-infoset"></a>B Reduced XML Infoset</h2><p><em>This appendix is normative.</em></p><p>For the purposes of this specification, a <a href="#terms-reduced-xml-infoset">reduced xml infoset</a> is
+an XML Information Set <a href="#infoset">[XML InfoSet]</a> that consists of only the following information items
+and information item properties:</p><div class="div2">
+<h3><a id="reduced-infoset-document"></a>B.1 Document Information Item</h3><ul><li><p><code>[document element]</code></p></li></ul></div><div class="div2">
+<h3><a id="reduced-infoset-element"></a>B.2 Element Information Item</h3><ul><li><p><code>[namespace URI]</code></p></li><li><p><code>[local name]</code></p></li><li><p><code>[children]</code></p></li><li><p><code>[attributes]</code></p></li></ul><p>Child information items <code>[children]</code> are reduced to only
+<a href="#terms-element-information-item">element information items</a> and
+<a href="#terms-character-information-item">character information items</a>.</p></div><div class="div2">
+<h3><a id="reduced-infoset-attribute"></a>B.3 Attribute Information Item</h3><ul><li><p><code>[namespace URI]</code></p></li><li><p><code>[local name]</code></p></li><li><p><code>[normalized value]</code></p></li></ul><div class="note"><p class="prefix"><b>Note:</b></p><p>See also <a href="#terms-attribute-information-item">attribute information item</a>.</p></div></div><div class="div2">
+<h3><a id="reduced-infoset-character"></a>B.4 Character Information Item</h3><ul><li><p><code>[character code]</code></p></li></ul><p>Contiguous character information items are not required to be represented distinctly,
+but may be aggregated (chunked) into a sequence of character codes (i.e., a character string).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>See also <a href="#terms-character-information-item">character information item</a>.</p></div></div></div><div class="div1">
+<h2><a id="schemas"></a>C Schemas</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the following schemas for use with
+<a href="#terms-document-instance">document instances</a>:</p><ul><li><p>Relax NG, Compact Syntax (RNC) Schema</p></li><li><p>XML Schema Definition (XSD) Schema</p></li></ul><p>In any case where a schema specified by this appendix differs from the
+normative definitions of document type, element type, or attribute type
+as defined by the body of this specification, then the body of this
+specification takes precedence.</p><div class="div2">
+<h3><a id="ttml-schema-rnc"></a>C.1 Relax NG Compact (RNC) Schema</h3><p>A Relax NG Compact Syntax (RNC) <a href="#rng">[RELAX NG]</a> based schema
+for TTML Content is available at <a href="rnc/schema.zip">ZIP
+Archive</a>. This schema is to be considered non-normative for the purpose of defining the validity
+of Timed Text Markup Language content as defined by this specification.
+In particular, the formal validity of TTML Content
+is defined by <a href="#conformance-content"><b>3.1 Document Conformance</b></a>.</p></div><div class="div2">
+<h3><a id="ttml-schema-xsd"></a>C.2 XML Schema Definition (XSD) Schema</h3><p>A W3C XML Schema Definition (XSD) <a href="#xsd-1">[XML Schema Part 1]</a> based schema
+for TTML Content is available at <a href="xsd/schema.zip">ZIP
+Archive</a>. This schema is to be considered non-normative for the purpose of defining the validity
+of Timed Text Markup Language content as defined by this specification.
+In particular, the formal validity of TTML Content
+is defined by <a href="#conformance-content"><b>3.1 Document Conformance</b></a>.</p></div></div><div class="div1">
+<h2><a id="media-types-registration"></a>D Media Type Registration</h2><p><em>This appendix is normative.</em></p><div class="issue"><p class="prefix"><a id="issue-352"></a><b>Issue (issue-352):</b></p><p class="prefix"><b>Restore Media Type Registration</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/352">http://www.w3.org/AudioVideo/TT/tracker/issues/352</a></p><p>Restore and update media type registration for IANA update.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p></p><div class="issue"><p class="prefix"><a id="issue-351"></a><b>Issue (issue-351):</b></p><p class="prefix"><b>Processor Profiles Parameter</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/351">http://www.w3.org/AudioVideo/TT/tracker/issues/351</a></p><p>Add definition of <code>processorProfiles</code> media type parameter.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div></div><div class="div1">
+<h2><a id="features"></a>E Features</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies (1) a set of feature designations, each of which
+labels one or more syntactic and/or semantic features defined by this
+specification, and (2) for each designated feature, whether the feature is mandatory
+or optional for a transformation or <a href="#terms-presentation-processor">presentation processor</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>A TTML processor is said to <em>implement the transformation semantics</em> or
+<em>implement the presentation semantics</em> of feature designation <em>F</em>
+if it satisfies the requirements of this appendix with respect to the definition of
+feature designation <em>F</em> as pertains to transformation or
+presentation processing, respectively.</p></div><div class="div2">
+<h3><a id="feature-designations"></a>E.1 Feature Designations</h3><p>A feature designation is expressed as a string that adheres to the following
+form:</p><div class="exampleInner"><pre>
+feature-designation
+  : feature-namespace designation
+
+feature-namespace
+  : <em>TT Feature Namespace</em>                    // http://www.w3.org/ns/ttml/feature/
+
+designation
+  : "#" token-char+
+
+token-char
+  : { XML NameChar }                        // XML 1.1 Production [4a]
+</pre></div><p>All values of <code>feature-designation</code> not defined by this specification are reserved
+for future standardization.</p><p>The following sub-sections define all feature designations, expressed
+as relative URIs (fragment identifiers) with respect to the 
+TT Feature Namespace base URI.</p><table border="1" class="ednote" summary="Editorial note: #animation subset features"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: #animation subset features</b></td><td align="right" valign="top">2013-08-26</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add fine grained subset features of #animation.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: #inline-region features"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: #inline-region features</b></td><td align="right" valign="top">2014-03-27</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add feature(s) associated with support for explicit and implied inline regions.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: New style property features"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: New style property features</b></td><td align="right" valign="top">2014-10-02</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add features to cover new style properties: border, fontVariantPosition, ruby, rubyAlign, rubyOffset, rubyPosition, textOrientation, etc.</td></tr></table><p></p><table border="1" class="ednote" summary="Editorial note: New embedded content features"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: New embedded content features</b></td><td align="right" valign="top">2014-11-27</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add features to cover new embedded content features: audio, data, font, image, etc.</td></tr></table><div class="div3">
+<h4><a id="feature-animation"></a>E.1.1 #animation</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#animation</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <a href="#animation"><b>13 Animation</b></a>:</p><ul><li><p><a href="#animation-vocabulary-animation"><code>animation</code></a></p></li><li><p><a href="#animation-vocabulary-animate"><code>animate</code></a></p></li><li><p><a href="#animation-vocabulary-set"><code>set</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#animation</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p></div><div class="div3">
+<h4><a id="feature-backgroundColor"></a>E.1.2 #backgroundColor</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#backgroundColor</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#backgroundColor</code> feature if it (1) implements presentation semantic support
+for the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
+attribute
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space.</p></div><div class="div3">
+<h4><a id="feature-backgroundColor-block"></a>E.1.3 #backgroundColor-block</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#backgroundColor-block</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
+attribute when applied to a content element that would generate a
+block area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#backgroundColor-block</code> feature if it (1) implements presentation semantic
+support for the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
+attribute when applied to a content element that generates a
+block area
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space.</p></div><div class="div3">
+<h4><a id="feature-backgroundColor-inline"></a>E.1.4 #backgroundColor-inline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#backgroundColor-inline</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
+attribute when applied to a content element that would generate an
+inline area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#backgroundColor-inline</code> feature if it (1) implements presentation semantic
+support for the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
+attribute when applied to a content element that generates an
+inline area
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space.</p></div><div class="div3">
+<h4><a id="feature-backgroundColor-region"></a>E.1.5 #backgroundColor-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#backgroundColor-region</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
+attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#backgroundColor-region</code> feature if it (1) implements presentation semantic
+support for the <a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a>
+attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space
+.</p></div><div class="div3">
+<h4><a id="feature-bidi"></a>E.1.6 #bidi</h4><p>A TTML processor supports the <code>#bidi</code> feature if it
+supports the following features:</p><ul><li><p><a href="#feature-direction"><code>#direction</code></a></p></li><li><p><a href="#feature-unicodeBidi"><code>#unicodeBidi</code></a></p></li><li><p><a href="#feature-writingMode-horizontal"><code>#writingMode-horizontal</code></a></p></li></ul></div><div class="div3">
+<h4><a id="feature-border"></a>E.1.7 #border</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#border</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-border"><code>tts:border</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#border</code> feature if it (1) implements presentation semantic support
+for the <a href="#style-attribute-border"><code>tts:border</code></a>
+attribute
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of border colors,
+including all primary and secondary colors of the SRGB color space.</p><table border="1" class="ednote" summary="Editorial note: Features related to tts:border"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Features related to tts:border</b></td><td align="right" valign="top">2013-08-23</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add additional border related features.</td></tr></table></div><div class="div3">
+<h4><a id="feature-cellResolution"></a>E.1.8 #cellResolution</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#cellResolution</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-cellResolution"><code>ttp:cellResolution</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#cellResolution</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-cellResolution"><code>ttp:cellResolution</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-clockMode"></a>E.1.9 #clockMode</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#clockMode</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#clockMode</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-clockMode-gps"></a>E.1.10 #clockMode-gps</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#clockMode-gps</code> feature if it recognizes and is capable of
+transforming the <code>gps</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#clockMode-gps</code> feature if it implements presentation semantic support
+for the <code>gps</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-clockMode-local"></a>E.1.11 #clockMode-local</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#clockMode-local</code> feature if it recognizes and is capable of
+transforming the <code>local</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#clockMode-local</code> feature if it implements presentation semantic support
+for the <code>local</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-clockMode-utc"></a>E.1.12 #clockMode-utc</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#clockMode-utc</code> feature if it recognizes and is capable of
+transforming the <code>utc</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#clockMode-utc</code> feature if it implements presentation semantic support
+for the <code>utc</code> value of the <a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-color"></a>E.1.13 #color</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#color</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-color"><code>tts:color</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#color</code> feature if it (1) implements presentation semantic support
+for the <a href="#style-attribute-color"><code>tts:color</code></a>
+attribute
+and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least sixteen (16) values of color,
+including all primary and secondary colors of the SRGB color space.</p></div><div class="div3">
+<h4><a id="feature-content"></a>E.1.14 #content</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#content</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <a href="#content"><b>8 Content</b></a>:</p><ul><li><p><a href="#document-structure-vocabulary-body"><code>body</code></a></p></li><li><p><a href="#content-vocabulary-div"><code>div</code></a></p></li><li><p><a href="#content-vocabulary-p"><code>p</code></a></p></li><li><p><a href="#content-vocabulary-span"><code>span</code></a></p></li><li><p><a href="#content-vocabulary-br"><code>br</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#content</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p></div><div class="div3">
+<h4><a id="feature-core"></a>E.1.15 #core</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#core</code>
+feature if it recognizes and is capable of transforming the following
+core attributes vocabulary defined by <a href="#content"><b>8 Content</b></a>:</p><ul><li><p><a href="#content-attribute-xml-id">@<code>xml:id</code></a></p></li><li><p><a href="#content-attribute-xml-id">@<code>xml:lang</code></a></p></li><li><p><a href="#content-attribute-xml-id">@<code>xml:space</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#core</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p></div><div class="div3">
+<h4><a id="feature-direction"></a>E.1.16 #direction</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#direction</code> feature if it recognizes and is capable of
+transforming all defined values of the <a href="#style-attribute-direction"><code>tts:direction</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#direction</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-direction"><code>tts:direction</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-display"></a>E.1.17 #display</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#display</code> feature if it recognizes and is capable of
+transforming all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#display</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-display-block"></a>E.1.18 #display-block</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#display-block</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
+attribute when applied to a content element that would generate a
+block area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#display-block</code> feature if it implements presentation semantic
+support for all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
+attribute when applied to a content element that generates a
+block area.</p></div><div class="div3">
+<h4><a id="feature-display-inline"></a>E.1.19 #display-inline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#display-inline</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
+attribute when applied to a content element that would generate an
+inline area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#display-inline</code> feature if it implements presentation semantic
+support for all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
+attribute when applied to a content element that generates an
+inline area.</p></div><div class="div3">
+<h4><a id="feature-display-region"></a>E.1.20 #display-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#display-region</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
+attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#display-region</code> feature if it implements presentation semantic
+support for all defined values of the <a href="#style-attribute-display"><code>tts:display</code></a>
+attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p></div><div class="div3">
+<h4><a id="feature-displayAlign"></a>E.1.21 #displayAlign</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#displayAlign</code> feature if it recognizes and is capable of
+transforming all defined values of the <a href="#style-attribute-displayAlign"><code>tts:displayAlign</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#displayAlign</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-displayAlign"><code>tts:displayAlign</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-dropMode"></a>E.1.22 #dropMode</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#dropMode</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#dropMode</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-dropMode-dropNTSC"></a>E.1.23 #dropMode-dropNTSC</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#dropMode-dropNTSC</code> feature if it recognizes and is capable of
+transforming the <code>dropNTSC</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#dropMode-dropNTSC</code> feature if it implements presentation semantic support
+for the <code>dropNTSC</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-dropMode-dropPAL"></a>E.1.24 #dropMode-dropPAL</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#dropMode-dropPAL</code> feature if it recognizes and is capable of
+transforming the <code>dropPAL</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#dropMode-dropPAL</code> feature if it implements presentation semantic support
+for the <code>dropPAL</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-dropMode-nonDrop"></a>E.1.25 #dropMode-nonDrop</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#dropMode-nonDrop</code> feature if it recognizes and is capable of
+transforming the <code>nonDrop</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#dropMode-nonDrop</code> feature if it implements presentation semantic support
+for the <code>nonDrop</code> value of the <a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-extent"></a>E.1.26 #extent</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#extent</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-extent"><code>tts:extent</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#extent</code> feature if it implements presentation semantic support for
+the <a href="#style-attribute-extent"><code>tts:extent</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-extent-region"></a>E.1.27 #extent-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#extent-region</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-extent"><code>tts:extent</code></a>
+attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#extent-region</code> feature if it implements presentation semantic support for
+the <a href="#style-attribute-extent"><code>tts:extent</code></a>
+attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p></div><div class="div3">
+<h4><a id="feature-extent-root"></a>E.1.28 #extent-root</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#extent-root</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-extent"><code>tts:extent</code></a>
+attribute when applied to the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#extent-root</code> feature if it implements presentation semantic support for
+the <a href="#style-attribute-extent"><code>tts:extent</code></a>
+attribute when applied to a <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element.</p></div><div class="div3">
+<h4><a id="feature-fontFamily"></a>E.1.29 #fontFamily</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontFamily</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontFamily</code> feature if it implements presentation semantic support
+for the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-fontFamily-generic"></a>E.1.30 #fontFamily-generic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontFamily-generic</code> feature if it recognizes and is
+capable of transforming <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a>
+values when used with the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontFamily-generic</code> feature if it implements presentation semantic
+support for <a href="#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a>
+values when used with the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-fontFamily-non-generic"></a>E.1.31 #fontFamily-non-generic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontFamily-non-generic</code> feature if it recognizes and is
+capable of transforming <a href="#style-value-familyName">&lt;familyName&gt;</a>
+values when used with the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontFamily-non-generic</code> feature if it implements presentation semantic
+support for <a href="#style-value-familyName">&lt;familyName&gt;</a>
+values when used with the <a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-fontSize"></a>E.1.32 #fontSize</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontSize</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontSize</code> feature if it implements presentation semantic support
+for the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-fontSize-anamorphic"></a>E.1.33 #fontSize-anamorphic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontSize-anamorphic</code> feature if it recognizes and is
+capable of transforming values of the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
+attribute that consist of two <a href="#style-value-length">&lt;length&gt;</a> specifications.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontSize-anamorphic</code> feature if it implements presentation semantic
+support for defined values of the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
+attribute that consist of two <a href="#style-value-length">&lt;length&gt;</a> specifications.</p></div><div class="div3">
+<h4><a id="feature-fontSize-isomorphic"></a>E.1.34 #fontSize-isomorphic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontSize-isomorphic</code> feature if it recognizes and is
+capable of transforming values of the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
+attribute that consist of a single <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontSize-isomorphic</code> feature if it implements presentation semantic
+support for defined values of the <a href="#style-attribute-fontSize"><code>tts:fontSize</code></a>
+attribute that consist of a single <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
+<h4><a id="feature-fontStyle"></a>E.1.35 #fontStyle</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontStyle</code> feature if it recognizes and is capable of
+transforming all defined values of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontStyle</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-fontStyle-italic"></a>E.1.36 #fontStyle-italic</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontStyle-italic</code> feature if it recognizes and is
+capable of transforming the <code>italic</code> value of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontStyle-italic</code> feature if it implements presentation semantic
+support for the <code>italic</code> of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-fontStyle-oblique"></a>E.1.37 #fontStyle-oblique</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontStyle-oblique</code> feature if it recognizes and is
+capable of transforming the <code>oblique</code> value of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontStyle-oblique</code> feature if it implements presentation semantic
+support for the <code>oblique</code> of the <a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-fontWeight"></a>E.1.38 #fontWeight</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontWeight</code> feature if it recognizes and is capable of
+transforming all defined values of the <a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontWeight</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-fontWeight-bold"></a>E.1.39 #fontWeight-bold</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#fontWeight-bold</code> feature if it recognizes and is
+capable of transforming <code>bold</code> value of the <a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#fontWeight-bold</code> feature if it implements presentation semantic
+support for the <code>bold</code> of the <a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-frameRate"></a>E.1.40 #frameRate</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#frameRate</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-frameRate"><code>ttp:frameRate</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#frameRate</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-frameRate"><code>ttp:frameRate</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-frameRateMultiplier"></a>E.1.41 #frameRateMultiplier</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#frameRateMultiplier</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-frameRateMultiplier"><code>ttp:frameRateMultiplier</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#frameRateMultiplier</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-frameRateMultiplier"><code>ttp:frameRateMultiplier</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-layout"></a>E.1.42 #layout</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#layout</code>
+feature if it (1) recognizes and is capable of transforming the following
+vocabulary defined by <a href="#layout"><b>11 Layout</b></a>:</p><ul><li><p><a href="#layout-vocabulary-layout"><code>layout</code></a></p></li><li><p><a href="#layout-vocabulary-region"><code>region</code></a></p></li><li><p><a href="#layout-attribute-region">@<code>region</code></a></p></li></ul><p>and (2) supports the following attributes when applied to the
+<a href="#layout-vocabulary-region"><code>region</code></a> element:</p><ul><li><p><a href="#style-attribute-extent"><code>tts:extent</code></a></p></li><li><p><a href="#style-attribute-origin"><code>tts:origin</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#layout</code>
+feature if it implements presentation semantic support for the
+same vocabulary and features enumerated above.</p></div><div class="div3">
+<h4><a id="feature-length"></a>E.1.43 #length</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#length</code>
+feature if it recognizes and is capable of transforming all defined
+values of the <a href="#style-value-length">&lt;length&gt;</a>
+style value expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#length</code>
+feature if it implements presentation semantic support for all defined values of
+the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length</code> is intended to imply support for the following features:
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>,
+<code>#length-negative</code>,
+<code>#length-cell</code>,
+<code>#length-em</code>,
+<code>#length-percentage</code>, and
+<code>#length-pixel</code>.</p></div></div><div class="div3">
+<h4><a id="feature-length-cell"></a>E.1.44 #length-cell</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#length-cell</code> feature if it recognizes and is capable of
+transforming scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
+that use <code>c</code> (cell) units.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#length-cell</code> feature if it implements presentation semantic support
+for scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
+that use <code>c</code> (cell) units.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-cell</code> does not, by itself, imply support for
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>, or
+<code>#length-negative</code> features.</p></div></div><div class="div3">
+<h4><a id="feature-length-em"></a>E.1.45 #length-em</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#length-em</code> feature if it recognizes and is capable of
+transforming scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
+that use <code>em</code> (EM) units.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#length-em</code> feature if it implements presentation semantic support
+for scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
+that use <code>em</code> (EM) units.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-em</code> does not, by itself, imply support for
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>, or
+<code>#length-negative</code> features.</p></div></div><div class="div3">
+<h4><a id="feature-length-integer"></a>E.1.46 #length-integer</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#length-integer</code> feature if it recognizes and is
+capable of transforming integer values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#length-integer</code> feature if it implements presentation semantic
+support for integer values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.
+</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-integer</code> does not, by itself, imply support for
+<code>#length-positive</code> or
+<code>#length-negative</code> features.</p></div></div><div class="div3">
+<h4><a id="feature-length-negative"></a>E.1.47 #length-negative</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#length-negative</code> feature if it recognizes and is
+capable of transforming negative values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#length-negative</code> feature if it implements presentation semantic
+support for negative values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.
+</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-negative</code> does not, by itself, imply support for
+<code>#length-integer</code> or
+<code>#length-real</code> features.</p></div></div><div class="div3">
+<h4><a id="feature-length-percentage"></a>E.1.48 #length-percentage</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#length-percentage</code> feature if it recognizes and is
+capable of transforming percentage values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#length-percentage</code> feature if it implements presentation semantic
+support for percentage values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.
+</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-percentage</code> does not, by itself, imply support for
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>, or
+<code>#length-negative</code> features.</p></div></div><div class="div3">
+<h4><a id="feature-length-pixel"></a>E.1.49 #length-pixel</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#length-pixel</code> feature if it recognizes and is capable of
+transforming scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
+that use <code>px</code> (pixel) units.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#length-pixel</code> feature if it implements presentation semantic support
+for scalar values of the <a href="#style-value-length">&lt;length&gt;</a> style value expression
+that use <code>px</code> (pixel) units.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-pixel</code> does not, by itself, imply support for
+<code>#length-integer</code>,
+<code>#length-real</code>,
+<code>#length-positive</code>, or
+<code>#length-negative</code> features.</p></div></div><div class="div3">
+<h4><a id="feature-length-positive"></a>E.1.50 #length-positive</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#length-positive</code> feature if it recognizes and is
+capable of transforming positive values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#length-positive</code> feature if it implements presentation semantic
+support for positive values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.
+</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-positive</code> is intended to imply support for zero valued
+<a href="#style-value-length">&lt;length&gt;</a> style value
+expressions.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-positive</code> does not, by itself, imply support for
+<code>#length-integer</code> or
+<code>#length-real</code> features.</p></div></div><div class="div3">
+<h4><a id="feature-length-real"></a>E.1.51 #length-real</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#length-real</code> feature if it recognizes and is
+capable of transforming real values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#length-real</code> feature if it implements presentation semantic
+support for real values of the <a href="#style-value-length">&lt;length&gt;</a> style value
+expression.
+</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-real</code> is intended to imply support for
+integer valued <a href="#style-value-length">&lt;length&gt;</a> style value
+expressions as well as real valued expressions.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>Support for <code>#length-real</code> does not, by itself, imply support for
+<code>#length-positive</code> or
+<code>#length-negative</code> features.</p></div></div><div class="div3">
+<h4><a id="feature-lineBreak-uax14"></a>E.1.52 #lineBreak-uax14</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#lineBreak-uax14</code> feature if it recognizes and is capable of
+transforming requirements expressed by <a href="#uax14">[UAX14]</a> into its
+target document space.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#lineBreak-uax14</code> feature if it implements presentation semantic support
+for <a href="#uax14">[UAX14]</a> as applies to line breaking.</p></div><div class="div3">
+<h4><a id="feature-lineHeight"></a>E.1.53 #lineHeight</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#lineHeight</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-lineHeight"><code>tts:lineHeight</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#lineHeight</code> feature if it implements presentation semantic support for
+the <a href="#style-attribute-lineHeight"><code>tts:lineHeight</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-markerMode"></a>E.1.54 #markerMode</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#markerMode</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#markerMode</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-markerMode-continuous"></a>E.1.55 #markerMode-continuous</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#markerMode-continuous</code> feature if it recognizes and is capable of
+transforming the <code>continuous</code> value of the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#markerMode-continuous</code> feature if it implements presentation semantic support
+for the <code>continuous</code> value of the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-markerMode-discontinuous"></a>E.1.56 #markerMode-discontinuous</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#markerMode-discontinuous</code> feature if it recognizes and is capable of
+transforming the <code>discontinuous</code> value of the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#markerMode-discontinuous</code> feature if it implements presentation semantic support
+for the <code>discontinuous</code> value of the <a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-metadata"></a>E.1.57 #metadata</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#metadata</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <a href="#metadata"><b>14 Metadata</b></a>:</p><ul><li><p><a href="#metadata-vocabulary-metadata"><code>metadata</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:title</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:desc</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:copyright</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:agent</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:name</code></a></p></li><li><p><a href="#metadata-vocabulary-title"><code>ttm:actor</code></a></p></li><li><p><a href="#metadata-attribute-agent">@<code>ttm:agent</code></a></p></li><li><p><a href="#metadata-attribute-role">@<code>ttm:role</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#metadata</code>
+feature if it recognizes and is capable of presenting the information
+expressed by the same vocabulary enumerated above.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not define a standardized form for the
+presentation of metadata information. The presentation or ability to
+present metadata information is considered to be implementation
+dependent.</p></div></div><div class="div3">
+<h4><a id="feature-nested-div"></a>E.1.58 #nested-div</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#nested-div</code>
+feature if it recognizes and is capable of transforming nested
+<a href="#content-vocabulary-div"><code>div</code></a> elements.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#nested-div</code>
+feature if it implements presentation semantic support for nested
+<a href="#content-vocabulary-div"><code>div</code></a> elements.</p></div><div class="div3">
+<h4><a id="feature-nested-span"></a>E.1.59 #nested-span</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#nested-span</code>
+feature if it recognizes and is capable of transforming nested
+<a href="#content-vocabulary-span"><code>span</code></a> elements.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#nested-span</code>
+feature if it implements presentation semantic support for nested
+<a href="#content-vocabulary-span"><code>span</code></a> elements.</p></div><div class="div3">
+<h4><a id="feature-opacity"></a>E.1.60 #opacity</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#opacity</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-opacity"><code>tts:opacity</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#opacity</code> feature if it (1) implements presentation semantic support for
+the <a href="#style-attribute-opacity"><code>tts:opacity</code></a>
+attribute and (2) is capable of displaying or generating an output display
+signal that distinguishes between at least eight (8) values of opacity.</p></div><div class="div3">
+<h4><a id="feature-origin"></a>E.1.61 #origin</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#origin</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-origin"><code>tts:origin</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#origin</code> feature if it implements presentation semantic support for
+the <a href="#style-attribute-origin"><code>tts:origin</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-overflow"></a>E.1.62 #overflow</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#overflow</code> feature if it recognizes and is capable of
+transforming all defined values of the <a href="#style-attribute-overflow"><code>tts:overflow</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#overflow</code> feature if it implements presentation semantic support for
+all defined values of the <a href="#style-attribute-overflow"><code>tts:overflow</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-overflow-visible"></a>E.1.63 #overflow-visible</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#overflow-visible</code> feature if it recognizes and is capable of
+transforming the <code>visible</code> value of the <a href="#style-attribute-overflow"><code>tts:overflow</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#overflow-visible</code> feature if it implements presentation semantic support for
+the <code>visible</code> value of the <a href="#style-attribute-overflow"><code>tts:overflow</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-padding"></a>E.1.64 #padding</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#padding</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-padding"><code>tts:padding</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#padding</code> feature if it implements presentation semantic support for
+the <a href="#style-attribute-padding"><code>tts:padding</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-padding-1"></a>E.1.65 #padding-1</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#padding-1</code> feature if it recognizes and is capable of
+transforming values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
+that consist of one <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#padding-1</code>
+feature if it implements presentation semantic support for values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
+that consist of one <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
+<h4><a id="feature-padding-2"></a>E.1.66 #padding-2</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#padding-2</code> feature if it recognizes and is capable of
+transforming values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
+that consist of two <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#padding-2</code>
+feature if it implements presentation semantic support for values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
+that consist of two <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
+<h4><a id="feature-padding-3"></a>E.1.67 #padding-3</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#padding-3</code> feature if it recognizes and is capable of
+transforming values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
+that consist of three <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#padding-3</code>
+feature if it implements presentation semantic support for values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
+that consist of three <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
+<h4><a id="feature-padding-4"></a>E.1.68 #padding-4</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#padding-4</code> feature if it recognizes and is capable of
+transforming values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
+that consist of four <a href="#style-value-length">&lt;length&gt;</a> specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#padding-4</code>
+feature if it implements presentation semantic support for values of the <a href="#style-attribute-padding"><code>tts:padding</code></a> attribute
+that consist of four <a href="#style-value-length">&lt;length&gt;</a> specification.</p></div><div class="div3">
+<h4><a id="feature-pixelAspectRatio"></a>E.1.69 #pixelAspectRatio</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#pixelAspectRatio</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-pixelAspectRatio"><code>ttp:pixelAspectRatio</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#pixelAspectRatio</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-pixelAspectRatio"><code>ttp:pixelAspectRatio</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-presentation"></a>E.1.70 #presentation</h4><p>A TTML processor supports the
+<code>#presentation</code> feature if it
+(1) satisfies the generic processor criteria defined by 
+<a href="#conformance-generic-processor"><b>3.2.1 Generic Processor Conformance</b></a>,
+(2) implements support for the region and line layout
+semantics defined by <a href="#semantics-region-layout"><b>11.3.1 Region Layout and Presentation</b></a> and
+<a href="#semantics-line-layout"><b>11.3.2 Line Layout</b></a>, respectively, and
+(3) implements presentation semantics for the following features:</p><ul><li><p><a href="#content"><code>#content</code></a></p></li><li><p><a href="#feature-core"><code>#core</code></a></p></li><li><p><a href="#feature-profile"><code>#profile</code></a></p></li><li><p><a href="#feature-structure"><code>#structure</code></a></p></li><li><p><a href="#feature-time-offset"><code>#time-offset</code></a></p></li><li><p><a href="#timing"><code>#timing</code></a></p></li></ul><p>
+In addition, a TTML processor that supports the
+<code>#presentation</code> feature should satisfy the user agent
+accessibility guidelines specified by <a href="#uaag">[UAAG]</a>.</p></div><div class="div3">
+<h4><a id="feature-profile"></a>E.1.71 #profile</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#profile</code>
+feature if it recognizes and is capable of transforming the
+<a href="#profile-attribute-profile"><code>ttp:profile</code></a>
+attribute on the <a href="#document-structure-vocabulary-tt"><code>tt</code></a> element and
+transforming the following vocabulary defined by
+<a href="#parameter-element-vocabulary"><b>7.1 Parameter Element Vocabulary</b></a>:</p><ul><li><p><a href="#profile-vocabulary-profile"><code>ttp:profile</code></a></p></li><li><p><a href="#profile-vocabulary-features"><code>ttp:features</code></a></p></li><li><p><a href="#profile-vocabulary-feature"><code>ttp:feature</code></a></p></li><li><p><a href="#profile-vocabulary-extensions"><code>ttp:extensions</code></a></p></li><li><p><a href="#profile-vocabulary-extension"><code>ttp:extension</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#profile</code> feature if it implements presentation semantic support
+for the same vocabulary specified above.</p></div><div class="div3">
+<h4><a id="feature-showBackground"></a>E.1.72 #showBackground</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#showBackground</code> feature if it recognizes and is capable
+of transforming all defined values of the <a href="#style-attribute-showBackground"><code>tts:showBackground</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#showBackground</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-showBackground"><code>tts:showBackground</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-structure"></a>E.1.73 #structure</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#structure</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <a href="#content"><b>8 Content</b></a>:</p><ul><li><p><a href="#document-structure-vocabulary-tt"><code>tt</code></a></p></li><li><p><a href="#document-structure-vocabulary-head"><code>head</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#structure</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p></div><div class="div3">
+<h4><a id="feature-styling"></a>E.1.74 #styling</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#styling</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <a href="#styling"><b>10 Styling</b></a>:</p><ul><li><p><a href="#styling-vocabulary-styling"><code>styling</code></a></p></li><li><p><a href="#styling-vocabulary-style"><code>style</code></a></p></li><li><p><a href="#style-attribute-style">@<code>style</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#styling</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p></div><div class="div3">
+<h4><a id="feature-styling-chained"></a>E.1.75 #styling-chained</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#styling-chained</code> feature if it recognizes and is capable
+of transforming chained style association as defined by <a href="#semantics-style-association-chained-referential"><b>10.4.1.3 Chained Referential Styling</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#styling-chained</code> feature if it implements presentation semantic
+support for chained style association as defined by <a href="#semantics-style-association-chained-referential"><b>10.4.1.3 Chained Referential Styling</b></a>.</p></div><div class="div3">
+<h4><a id="feature-styling-inheritance-content"></a>E.1.76 #styling-inheritance-content</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#styling-inheritance</code> feature if it recognizes and is
+capable of transforming content style inheritance as defined by
+<a href="#semantics-style-inheritance-content"><b>10.4.2.1 Content Style Inheritance</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#styling-inheritance-content</code> feature if it implements
+presentation semantic support for content style inheritance as defined by <a href="#semantics-style-inheritance-content"><b>10.4.2.1 Content Style Inheritance</b></a>.</p></div><div class="div3">
+<h4><a id="feature-styling-inheritance-region"></a>E.1.77 #styling-inheritance-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#styling-inheritance</code> feature if it recognizes and is
+capable of transforming region style inheritance as defined by
+<a href="#semantics-style-inheritance-region"><b>10.4.2.2 Region Style Inheritance</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#styling-inheritance-region</code> feature if it implements
+presentation semantic support for region style inheritance as defined by <a href="#semantics-style-inheritance-region"><b>10.4.2.2 Region Style Inheritance</b></a>.</p></div><div class="div3">
+<h4><a id="feature-styling-inline"></a>E.1.78 #styling-inline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#styling-inline</code> feature if it recognizes and is capable
+of transforming inline style association as defined by <a href="#semantics-style-association-inline"><b>10.4.1.1 Inline Styling</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#styling-inline</code> feature if it implements presentation semantic support
+for inline style association as defined by <a href="#semantics-style-association-inline"><b>10.4.1.1 Inline Styling</b></a>.</p></div><div class="div3">
+<h4><a id="feature-styling-nested"></a>E.1.79 #styling-nested</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#styling-nested</code> feature if it recognizes and is capable
+of transforming nested style association as defined by <a href="#semantics-style-association-nested"><b>10.4.1.4 Nested Styling</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#styling-nested</code> feature if it implements presentation semantic support
+for nested style association as defined by <a href="#semantics-style-association-nested"><b>10.4.1.4 Nested Styling</b></a>.</p></div><div class="div3">
+<h4><a id="feature-styling-referential"></a>E.1.80 #styling-referential</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#styling-referential</code> feature if it recognizes and is capable
+of transforming referential style association as defined by <a href="#semantics-style-association-referential"><b>10.4.1.2 Referential Styling</b></a>.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#styling-referential</code> feature if it implements presentation semantic
+support for referential style association as defined by <a href="#semantics-style-association-referential"><b>10.4.1.2 Referential Styling</b></a>.</p></div><div class="div3">
+<h4><a id="feature-subFrameRate"></a>E.1.81 #subFrameRate</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#subFrameRate</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-subFrameRate"><code>ttp:subFrameRate</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#subFrameRate</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-subFrameRate"><code>ttp:subFrameRate</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textAlign"></a>E.1.82 #textAlign</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textAlign</code> feature if it recognizes and is capable
+of transforming all defined values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textAlign</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textAlign-absolute"></a>E.1.83 #textAlign-absolute</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textAlign-absolute</code> feature if it recognizes and is
+capable of transforming the <code>left</code>, <code>center</code>,
+and <code>right</code> values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textAlign-absolute</code> feature if it implements presentation semantic
+support for the <code>left</code>, <code>center</code>, and
+<code>right</code> values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textAlign-relative"></a>E.1.84 #textAlign-relative</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textAlign-relative</code> feature if it recognizes and is
+capable of transforming the <code>start</code>, <code>center</code>,
+and <code>end</code> values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textAlign-relative</code> feature if it implements presentation semantic
+support for the <code>start</code>, <code>center</code>, and
+<code>end</code> values of the <a href="#style-attribute-textAlign"><code>tts:textAlign</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textDecoration"></a>E.1.85 #textDecoration</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textDecoration</code> feature if it recognizes and is capable
+of transforming all defined values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textDecoration</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textDecoration-over"></a>E.1.86 #textDecoration-over</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textDecoration-over</code> feature if it recognizes and is
+capable of transforming the <code>overline</code> and
+<code>noOverline</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textDecoration-over</code> feature if it implements
+presentation semantic support for the <code>overline</code> and
+<code>noOverline</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textDecoration-through"></a>E.1.87 #textDecoration-through</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textDecoration-through</code> feature if it recognizes and is
+capable of transforming the <code>lineThrough</code> and
+<code>noLineThrough</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textDecoration-through</code> feature if it implements
+presentation semantic support for the <code>lineThrough</code> and
+<code>noLineThrough</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textDecoration-under"></a>E.1.88 #textDecoration-under</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textDecoration-under</code> feature if it recognizes and is
+capable of transforming the <code>underline</code> and
+<code>noUnderline</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textDecoration-under</code> feature if it implements
+presentation semantic support for the <code>underline</code> and
+<code>noUnderline</code> values of the <a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textOrientation"></a>E.1.89 #textOrientation</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textOrientation</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-textOrientation"><code>tts:textOrientation</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textOrientation</code> feature if it implements presentation semantic support
+for the <a href="#style-attribute-textOrientation"><code>tts:textOrientation</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textOutline"></a>E.1.90 #textOutline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textOutline</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textOutline</code> feature if it implements presentation semantic support
+for the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-textOutline-blurred"></a>E.1.91 #textOutline-blurred</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textOutline-blurred</code> feature if it recognizes and is capable of
+transforming values of the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
+attribute that includes a blur radius specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textOutline-blurred</code> feature if it implements presentation semantic support
+for values of the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
+attribute that includes a blur radius specification.</p></div><div class="div3">
+<h4><a id="feature-textOutline-unblurred"></a>E.1.92 #textOutline-unblurred</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#textOutline-unblurred</code> feature if it recognizes and is capable of
+transforming values of the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
+attribute that does not include a blur radius specification.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#textOutline-unblurred</code> feature if it implements presentation semantic support
+for values of the <a href="#style-attribute-textOutline"><code>tts:textOutline</code></a>
+attribute that does not include a blur radius specification.</p></div><div class="div3">
+<h4><a id="feature-tickRate"></a>E.1.93 #tickRate</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#tickRate</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-tickRate"><code>ttp:tickRate</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#tickRate</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-tickRate"><code>ttp:tickRate</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-timeBase-clock"></a>E.1.94 #timeBase-clock</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#timeBase-clock</code> feature if it recognizes and is capable
+of transforming the <code>clock</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
+attribute and if it supports the <a href="#feature-clockMode"><code>#clockMode</code></a> feature.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#timeBase-clock</code> feature if it implements presentation
+semantic support for the <code>clock</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
+attribute and if it supports the <a href="#feature-clockMode"><code>#clockMode</code></a> feature.</p></div><div class="div3">
+<h4><a id="feature-timeBase-media"></a>E.1.95 #timeBase-media</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#timeBase-media</code> feature if it recognizes and is capable
+of transforming the <code>media</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#timeBase-media</code> feature if it implements presentation
+semantic support for the <code>media</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-timeBase-smpte"></a>E.1.96 #timeBase-smpte</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#timeBase-smpte</code> feature if it recognizes and is capable
+of transforming the <code>smpte</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
+attribute and if it supports the <a href="#feature-dropMode"><code>#dropMode</code></a> feature.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#timeBase-smpte</code> feature if it implements presentation
+semantic support for the <code>smpte</code> value of the <a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a>
+attribute and if it supports the <a href="#feature-dropMode"><code>#dropMode</code></a> feature.</p></div><div class="div3">
+<h4><a id="feature-timeContainer"></a>E.1.97 #timeContainer</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#timeContainer</code> feature if it recognizes and is capable of
+transforming the <a href="#timing-attribute-timeContainer"><code>timeContainer</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#timeContainer</code> feature if it implements presentation semantic support
+for the <a href="#timing-attribute-timeContainer"><code>timeContainer</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-time-clock"></a>E.1.98 #time-clock</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#time-clock</code> feature if it recognizes and is capable of
+transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
+satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
+&lt;timeExpression&gt;
+  : hours ":" minutes ":" seconds ( fraction )?
+</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#time-clock</code> feature if it implements presentation
+semantic support for the same syntax specified above.</p></div><div class="div3">
+<h4><a id="feature-time-clock-with-frames"></a>E.1.99 #time-clock-with-frames</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#time-clock-with-frames</code> feature if it supports the
+<a href="#feature-frameRate"><code>#frameRate</code></a>,
+<a href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></a>, and
+<a href="#feature-subFrameRate"><code>#subFrameRate</code></a> features
+and if it recognizes and is capable of
+transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
+satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
+&lt;timeExpression&gt;
+  : hours ":" minutes ":" seconds ( fraction | ":" frames ( "." sub-frames )? )?
+</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#time-clock-with-frames</code> feature if it implements
+presentation semantic support for the same features and syntax
+specified above.</p></div><div class="div3">
+<h4><a id="feature-time-offset"></a>E.1.100 #time-offset</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#time-offset</code> feature if it recognizes and is capable of
+transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
+satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
+&lt;timeExpression&gt;
+  : time-count fraction? ( "h" | "m" | "s" | "ms" )
+</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#time-offset</code> feature if it implements presentation
+semantic support for the same syntax specified above.</p></div><div class="div3">
+<h4><a id="feature-time-offset-with-frames"></a>E.1.101 #time-offset-with-frames</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#time-offset-with-frames</code> feature if it supports the
+<a href="#feature-frameRate"><code>#frameRate</code></a>,
+<a href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></a>, and
+<a href="#feature-subFrameRate"><code>#subFrameRate</code></a> features
+and if it recognizes and is capable of
+transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
+satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
+&lt;timeExpression&gt;
+  : time-count fraction? "f"
+</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#time-offset-with-frames</code> feature if it implements
+presentation semantic support for the same features and syntax
+specified above.</p></div><div class="div3">
+<h4><a id="feature-time-offset-with-ticks"></a>E.1.102 #time-offset-with-ticks</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#time-offset-with-ticks</code> feature if it supports the 
+<a href="#feature-tickRate"><code>#tickRate</code></a> feature
+and if it recognizes and is capable of
+transforming all values of the <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a> that
+satisfy the following subset of time expression syntax:</p><div class="exampleInner"><pre>
+&lt;timeExpression&gt;
+  : time-count fraction? "t"
+</pre></div><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#time-offset-with-ticks</code> feature if it implements presentation
+semantic support for the same features and syntax specified above.</p></div><div class="div3">
+<h4><a id="feature-timing"></a>E.1.103 #timing</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the <code>#timing</code>
+feature if it recognizes and is capable of transforming the following
+vocabulary defined by <a href="#timing"><b>12 Timing</b></a>:</p><ul><li><p><a href="#timing-attribute-begin">@<code>begin</code></a></p></li><li><p><a href="#timing-attribute-dur">@<code>dur</code></a></p></li><li><p><a href="#timing-attribute-end">@<code>end</code></a></p></li></ul><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the <code>#timing</code>
+feature if it implements presentation semantic support for the
+same vocabulary enumerated above.</p></div><div class="div3">
+<h4><a id="feature-transformation"></a>E.1.104 #transformation</h4><p>A TTML processor supports the
+<code>#transformation</code> feature if it
+(1) satisfies the generic processor criteria defined by 
+<a href="#conformance-generic-processor"><b>3.2.1 Generic Processor Conformance</b></a> and
+(2) implements the transformation semantics of the following features:</p><ul><li><p><a href="#content"><code>#content</code></a></p></li><li><p><a href="#feature-core"><code>#core</code></a></p></li><li><p><a href="#feature-profile"><code>#profile</code></a></p></li><li><p><a href="#feature-structure"><code>#structure</code></a></p></li><li><p><a href="#feature-time-offset"><code>#time-offset</code></a></p></li><li><p><a href="#timing"><code>#timing</code></a></p></li></ul></div><div class="div3">
+<h4><a id="feature-unicodeBidi"></a>E.1.105 #unicodeBidi</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#unicodeBidi</code> feature if it recognizes and is capable of
+transforming all defined values of the <a href="#style-attribute-unicodeBidi"><code>tts:unicodeBidi</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#unicodeBidi</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-unicodeBidi"><code>tts:unicodeBidi</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-version"></a>E.1.106 #version</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#version</code> feature if it recognizes and is capable of
+transforming the <a href="#parameter-attribute-version"><code>ttp:version</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#version</code> feature if it implements presentation semantic support
+for the <a href="#parameter-attribute-version"><code>ttp:version</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-visibility"></a>E.1.107 #visibility</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#visibility</code> feature if it recognizes and is capable
+of transforming all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#visibility</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-visibility-block"></a>E.1.108 #visibility-block</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#visibility-block</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
+attribute when applied to a content element that would generate a
+block area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#visibility-block</code> feature if it implements presentation semantic
+support for all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
+attribute when applied to a content element that generates a
+block area.</p></div><div class="div3">
+<h4><a id="feature-visibility-inline"></a>E.1.109 #visibility-inline</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#visibility-inline</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
+attribute when applied to a content element that would generate an
+inline area during presentation processing.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#visibility-inline</code> feature if it implements presentation semantic
+support for all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
+attribute when applied to a content element that generates an
+inline area.</p></div><div class="div3">
+<h4><a id="feature-visibility-region"></a>E.1.110 #visibility-region</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#visibility-region</code> feature if it recognizes and is
+capable of transforming all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
+attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#visibility-region</code> feature if it implements presentation semantic
+support for all defined values of the <a href="#style-attribute-visibility"><code>tts:visibility</code></a>
+attribute when applied to a <a href="#layout-vocabulary-region"><code>region</code></a> element.</p></div><div class="div3">
+<h4><a id="feature-wrapOption"></a>E.1.111 #wrapOption</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#wrapOption</code> feature if it recognizes and is capable
+of transforming all defined values of the <a href="#style-attribute-wrapOption"><code>tts:wrapOption</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#wrapOption</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-wrapOption"><code>tts:wrapOption</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-writingMode"></a>E.1.112 #writingMode</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#writingMode</code> feature if it recognizes and is capable
+of transforming all defined values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#writingMode</code> feature if it implements presentation semantic support
+for all defined values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-writingMode-vertical"></a>E.1.113 #writingMode-vertical</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#writingMode-vertical</code> feature if it recognizes and is
+capable of transforming the <code>tbrl</code>, <code>tblr</code>, and
+<code>tb</code> values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#writingMode-vertical</code> feature if it implements presentation semantic
+support for the <code>tbrl</code>, <code>tblr</code>, and
+<code>tb</code> values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-writingMode-horizontal"></a>E.1.114 #writingMode-horizontal</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#writingMode-horizontal</code> feature if it recognizes and is
+capable of transforming the <code>lrtb</code>, <code>rltb</code>,
+<code>lr</code> and <code>rl</code> values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#writingMode-horizontal</code> feature if it implements presentation semantic
+support for the <code>lrtb</code>, <code>rltb</code>, <code>lr</code>
+and <code>rl</code> values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-writingMode-horizontal-lr"></a>E.1.115 #writingMode-horizontal-lr</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#writingMode-horizontal</code> feature if it recognizes and is
+capable of transforming the <code>lrtb</code> and <code>lr</code>
+values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#writingMode-horizontal-lr</code> feature if it implements presentation semantic
+support for the <code>lrtb</code> and <code>lr</code> values of the
+<a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-writingMode-horizontal-rl"></a>E.1.116 #writingMode-horizontal-rl</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#writingMode-horizontal</code> feature if it recognizes and is
+capable of transforming the <code>rltb</code> and <code>rl</code>
+values of the <a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#writingMode-horizontal-rl</code> feature if it implements presentation semantic
+support for the <code>rltb</code> and <code>rl</code> values of the
+<a href="#style-attribute-writingMode"><code>tts:writingMode</code></a>
+attribute.</p></div><div class="div3">
+<h4><a id="feature-zIndex"></a>E.1.117 #zIndex</h4><p>A TTML <a href="#terms-transformation-processor">transformation processor</a> supports the
+<code>#zIndex</code> feature if it recognizes and is capable of
+transforming the <a href="#style-attribute-zIndex"><code>tts:zIndex</code></a>
+attribute.</p><p>A TTML <a href="#terms-presentation-processor">presentation processor</a> supports the
+<code>#zIndex</code> feature if it implements presentation semantic support for
+the <a href="#style-attribute-zIndex"><code>tts:zIndex</code></a>
+attribute.</p></div></div><div class="div2">
+<h3><a id="feature-support"></a>E.2 Feature Support</h3><p>The following table, <a href="#feature-support-table"><b>Table E-1 – Feature Support</b></a>,
+enumerates every defined feature designation (expressed without the TT
+Feature Namespace), and, for each designated feature, specifies
+whether the feature must be implemented, i.e., is mandatory (M), or may be implemented, i.e.,
+is optional (O), for transformation and <a href="#terms-presentation-processor">presentation processor</a>s.</p><a id="feature-support-table"></a><table class="common"><caption>Table E-1 – Feature Support</caption><col width="60%" span="1"><col width="20%" span="1"><col width="20%" span="1"><tbody><tr><td><span class="strong">Feature</span></td><td><span class="strong">Transformation</span></td><td><span class="strong">Presentation</span></td></tr><tr><td><a href="#feature-animation"><code>#animation</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-backgroundColor"><code>#backgroundColor</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-backgroundColor-block"><code>#backgroundColor-block</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-backgroundColor-inline"><code>#backgroundColor-inline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-backgroundColor-region"><code>#backgroundColor-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-bidi"><code>#bidi</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-border"><code>#border</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-cellResolution"><code>#cellResolution</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-clockMode"><code>#clockMode</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-clockMode-gps"><code>#clockMode-gps</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-clockMode-local"><code>#clockMode-local</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-clockMode-utc"><code>#clockMode-utc</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-color"><code>#color</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-content"><code>#content</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-core"><code>#core</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-direction"><code>#direction</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-display"><code>#display</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-display-block"><code>#display-block</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-display-inline"><code>#display-inline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-display-region"><code>#display-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-displayAlign"><code>#displayAlign</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-dropMode"><code>#dropMode</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-dropMode-dropNTSC"><code>#dropMode-dropNTSC</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-dropMode-dropPAL"><code>#dropMode-dropPAL</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-dropMode-nonDrop"><code>#dropMode-nonDrop</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-extent"><code>#extent</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-extent-region"><code>#extent-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-extent-root"><code>#extent-root</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontFamily"><code>#fontFamily</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontFamily-generic"><code>#fontFamily-generic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontFamily-non-generic"><code>#fontFamily-non-generic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontSize"><code>#fontSize</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontSize-anamorphic"><code>#fontSize-anamorphic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontSize-isomorphic"><code>#fontSize-isomorphic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontStyle"><code>#fontStyle</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontStyle-italic"><code>#fontStyle-italic</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontStyle-oblique"><code>#fontStyle-oblique</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontWeight"><code>#fontWeight</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-fontWeight-bold"><code>#fontWeight-bold</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-frameRate"><code>#frameRate</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-frameRateMultiplier"><code>#frameRateMultiplier</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-layout"><code>#layout</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length"><code>#length</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-cell"><code>#length-cell</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-em"><code>#length-em</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-integer"><code>#length-integer</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-negative"><code>#length-negative</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-percentage"><code>#length-percentage</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-pixel"><code>#length-pixel</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-positive"><code>#length-positive</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-length-real"><code>#length-real</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-lineBreak-uax14"><code>#lineBreak-uax14</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-lineHeight"><code>#lineHeight</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-markerMode"><code>#markerMode</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-markerMode-continuous"><code>#markerMode-continuous</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-markerMode-discontinuous"><code>#markerMode-discontinuous</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-metadata"><code>#metadata</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-nested-div"><code>#nested-div</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-nested-span"><code>#nested-span</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-opacity"><code>#opacity</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-origin"><code>#origin</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-overflow"><code>#overflow</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-overflow-visible"><code>#overflow-visible</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding"><code>#padding</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding-1"><code>#padding-1</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding-2"><code>#padding-2</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding-3"><code>#padding-3</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-padding-4"><code>#padding-4</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-pixelAspectRatio"><code>#pixelAspectRatio</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-presentation"><code>#presentation</code></a></td><td>O</td><td>M</td></tr><tr><td><a href="#feature-profile"><code>#profile</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-showBackground"><code>#showBackground</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-structure"><code>#structure</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-styling"><code>#styling</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-chained"><code>#styling-chained</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-inheritance-content"><code>#styling-inheritance-content</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-inheritance-region"><code>#styling-inheritance-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-inline"><code>#styling-inline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-nested"><code>#styling-nested</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-styling-referential"><code>#styling-referential</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-subFrameRate"><code>#subFrameRate</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textAlign"><code>#textAlign</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textAlign-absolute"><code>#textAlign-absolute</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textAlign-relative"><code>#textAlign-relative</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textDecoration"><code>#textDecoration</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textDecoration-over"><code>#textDecoration-over</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textDecoration-through"><code>#textDecoration-through</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textDecoration-under"><code>#textDecoration-under</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textOrientation"><code>#textOrientation</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textOutline"><code>#textOutline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textOutline-blurred"><code>#textOutline-blurred</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-textOutline-unblurred"><code>#textOutline-unblurred</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-tickRate"><code>#tickRate</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timeBase-clock"><code>#timeBase-clock</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timeBase-media"><code>#timeBase-media</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timeBase-smpte"><code>#timeBase-smpte</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timeContainer"><code>#timeContainer</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-time-clock"><code>#time-clock</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-time-clock-with-frames"><code>#time-clock-with-frames</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-time-offset"><code>#time-offset</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-time-offset-with-frames"><code>#time-offset-with-frames</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-time-offset-with-ticks"><code>#time-offset-with-ticks</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-timing"><code>#timing</code></a></td><td>M</td><td>M</td></tr><tr><td><a href="#feature-transformation"><code>#transformation</code></a></td><td>M</td><td>O</td></tr><tr><td><a href="#feature-unicodeBidi"><code>#unicodeBidi</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-version"><code>#version</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-visibility"><code>#visibility</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-visibility-block"><code>#visibility-block</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-visibility-inline"><code>#visibility-inline</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-visibility-region"><code>#visibility-region</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-wrapOption"><code>#wrapOption</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode"><code>#writingMode</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode-vertical"><code>#writingMode-vertical</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode-horizontal"><code>#writingMode-horizontal</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode-horizontal-lr"><code>#writingMode-horizontal-lr</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-writingMode-horizontal-rl"><code>#writingMode-horizontal-rl</code></a></td><td>O</td><td>O</td></tr><tr><td><a href="#feature-zIndex"><code>#zIndex</code></a></td><td>O</td><td>O</td></tr></tbody></table><p>For the sake of convenience, the following table,
+<a href="#feature-transformation-mandatory-table"><b>Table E-2 – Mandatory Features - Transformation</b></a>, enumerates all
+mandatory features for a TTML <a href="#terms-transformation-processor">transformation processor</a>, providing additional
+comments to summarize the context of usage or the nature of the feature.
+The <a href="#terms-profile-definition-document">profile definition document</a> that defines the corresponding
+TTML Transformation Profile is specified in
+<a href="#profile-ttml2-transformation"><b>G.3 TTML2 Transformation Profile</b></a>.
+</p><a id="feature-transformation-mandatory-table"></a><table class="common"><caption>Table E-2 – Mandatory Features - Transformation</caption><col width="60%" span="1"><col width="40%" span="1"><tbody><tr><td><span class="strong">Feature</span></td><td><span class="strong">Comments</span></td></tr><tr><td><a href="#feature-content"><code>#content</code></a></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>,
+<a href="#content-vocabulary-br"><code>br</code></a>
+</td></tr><tr><td><a href="#feature-core"><code>#core</code></a></td><td>
+<a href="#content-attribute-xml-id">@<code>xml:id</code></a>,
+<a href="#content-attribute-xml-id">@<code>xml:lang</code></a>,
+<a href="#content-attribute-xml-id">@<code>xml:space</code></a>
+</td></tr><tr><td><a href="#feature-profile"><code>#profile</code></a></td><td></td></tr><tr><td><a href="#feature-structure"><code>#structure</code></a></td><td>
+<a href="#document-structure-vocabulary-tt"><code>tt</code></a>,
+<a href="#document-structure-vocabulary-head"><code>head</code></a>
+</td></tr><tr><td><a href="#feature-time-offset"><code>#time-offset</code></a></td><td></td></tr><tr><td><a href="#feature-timing"><code>#timing</code></a></td><td>
+<a href="#timing-attribute-begin">@<code>begin</code></a>,
+<a href="#timing-attribute-dur">@<code>dur</code></a>,
+<a href="#timing-attribute-end">@<code>end</code></a>
+</td></tr><tr><td><a href="#feature-transformation"><code>#transformation</code></a></td><td></td></tr></tbody></table><p>For the sake of convenience, the following table,
+<a href="#feature-presentation-mandatory-table"><b>Table E-3 – Mandatory Features - Presentation</b></a>, enumerates all
+mandatory features for a TTML <a href="#terms-presentation-processor">presentation processor</a>, providing additional
+comments to summarize the context of usage or the nature of the feature.
+The <a href="#terms-profile-definition-document">profile definition document</a> that defines the corresponding
+TTML Presentation Profile is specified in
+<a href="#profile-ttml2-presentation"><b>G.2 TTML2 Presentation Profile</b></a>.
+</p><a id="feature-presentation-mandatory-table"></a><table class="common"><caption>Table E-3 – Mandatory Features - Presentation</caption><col width="60%" span="1"><col width="40%" span="1"><tbody><tr><td><span class="strong">Feature</span></td><td><span class="strong">Comments</span></td></tr><tr><td><a href="#feature-content"><code>#content</code></a></td><td>
+<a href="#document-structure-vocabulary-body"><code>body</code></a>,
+<a href="#content-vocabulary-div"><code>div</code></a>,
+<a href="#content-vocabulary-p"><code>p</code></a>,
+<a href="#content-vocabulary-span"><code>span</code></a>,
+<a href="#content-vocabulary-br"><code>br</code></a>
+</td></tr><tr><td><a href="#feature-core"><code>#core</code></a></td><td>
+<a href="#content-attribute-xml-id">@<code>xml:id</code></a>,
+<a href="#content-attribute-xml-id">@<code>xml:lang</code></a>,
+<a href="#content-attribute-xml-id">@<code>xml:space</code></a>
+</td></tr><tr><td><a href="#feature-profile"><code>#profile</code></a></td><td></td></tr><tr><td><a href="#feature-presentation"><code>#presentation</code></a></td><td></td></tr><tr><td><a href="#feature-structure"><code>#structure</code></a></td><td>
+<a href="#document-structure-vocabulary-tt"><code>tt</code></a>,
+<a href="#document-structure-vocabulary-head"><code>head</code></a>
+</td></tr><tr><td><a href="#feature-time-offset"><code>#time-offset</code></a></td><td></td></tr><tr><td><a href="#feature-timing"><code>#timing</code></a></td><td>
+<a href="#timing-attribute-begin">@<code>begin</code></a>,
+<a href="#timing-attribute-dur">@<code>dur</code></a>,
+<a href="#timing-attribute-end">@<code>end</code></a>
+</td></tr></tbody></table></div></div><div class="div1">
+<h2><a id="extensions"></a>F Extensions</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the syntactic form of extension designations, which are
+used to express authorial intent regarding the support for extension
+mechanisms in a TTML processor.</p><div class="div2">
+<h3><a id="extension-designations"></a>F.1 Extension Designations</h3><p>An extension designation is expressed as a string that adheres to the following
+form:</p><div class="exampleInner"><pre>
+extension-designation
+  : extension-namespace designation
+
+extension-namespace
+  : <em>TT Extension Namespace</em>                  // http://www.w3.org/ns/ttml/extension/
+  | <em>Other Extension Namespace</em>               // expressed as an absolute URI
+
+designation
+  : "#" token-char+
+
+token-char
+  : { XML NameChar }                        // XML 1.1 Production [4a]
+</pre></div><p>If the extension namespace of an extension designation is the TT
+Extension Namespace, then all values of the following
+<code>designation</code> token are reserved for future
+standardization.</p><p>If the extension namespace of an extension designation is not the
+TT Extension Namespace, i.e., is an <em>Other Extension Namespace</em>,
+then the extension namespace must be expressed as an absolute URI
+capable of serving as a base URI used in combination with a
+<code>designation</code> token that takes the form of a fragment
+identifier.</p></div></div><div class="div1">
+<h2><a id="standard-profiles"></a>G Standard Profiles</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the following standard TTML profiles:</p><ul><li><p><a href="#profile-ttml2-full"><b>G.1 TTML2 Full Profile</b></a></p></li><li><p><a href="#profile-ttml2-presentation"><b>G.2 TTML2 Presentation Profile</b></a></p></li><li><p><a href="#profile-ttml2-transformation"><b>G.3 TTML2 Transformation Profile</b></a></p></li></ul><p>Each TTML profile is defined in terms of a <a href="#terms-profile-definition-document">profile definition document</a>,
+which is expressed as an XML document wherein the root element adheres to
+<a href="#profile-vocabulary-profile"><b>6.1.1 ttp:profile</b></a>.</p><div class="div2">
+<h3><a id="profile-ttml2-full"></a>G.1 TTML2 Full Profile</h3><p>The TTML2 Full Profile is intended to be used to
+express maximum compliance for both transformation and presentation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This profile is a superset of the
+<a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml1/spec/ttml1.html#profile-dfxp-full">DFXP Full Profile</a>:
+it requires support for the
+<a href="#feature-version"><code>#border</code></a>,
+<a href="#feature-version"><code>#textOrientation</code></a>, and
+<a href="#feature-version"><code>#version</code></a>
+features.</p></div><div class="exampleInner"><pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
+&lt;!-- this file defines the "dfxp-full" profile of ttml --&gt;
+&lt;profile xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
+  &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+    &lt;!-- required (mandatory) feature support --&gt;
+    &lt;feature value="required"&gt;#animation&lt;/feature&gt;
+    &lt;feature value="required"&gt;#backgroundColor-block&lt;/feature&gt;
+    &lt;feature value="required"&gt;#backgroundColor-inline&lt;/feature&gt;
+    &lt;feature value="required"&gt;#backgroundColor-region&lt;/feature&gt;
+    &lt;feature value="required"&gt;#backgroundColor&lt;/feature&gt;
+    &lt;feature value="required"&gt;#bidi&lt;/feature&gt;
+    &lt;feature value="required"&gt;#border&lt;/feature&gt;
+    &lt;feature value="required"&gt;#cellResolution&lt;/feature&gt;
+    &lt;feature value="required"&gt;#clockMode-gps&lt;/feature&gt;
+    &lt;feature value="required"&gt;#clockMode-local&lt;/feature&gt;
+    &lt;feature value="required"&gt;#clockMode-utc&lt;/feature&gt;
+    &lt;feature value="required"&gt;#clockMode&lt;/feature&gt;
+    &lt;feature value="required"&gt;#color&lt;/feature&gt;
+    &lt;feature value="required"&gt;#content&lt;/feature&gt;
+    &lt;feature value="required"&gt;#core&lt;/feature&gt;
+    &lt;feature value="required"&gt;#direction&lt;/feature&gt;
+    &lt;feature value="required"&gt;#display-block&lt;/feature&gt;
+    &lt;feature value="required"&gt;#display-inline&lt;/feature&gt;
+    &lt;feature value="required"&gt;#display-region&lt;/feature&gt;
+    &lt;feature value="required"&gt;#display&lt;/feature&gt;
+    &lt;feature value="required"&gt;#displayAlign&lt;/feature&gt;
+    &lt;feature value="required"&gt;#dropMode-dropNTSC&lt;/feature&gt;
+    &lt;feature value="required"&gt;#dropMode-dropPAL&lt;/feature&gt;
+    &lt;feature value="required"&gt;#dropMode-nonDrop&lt;/feature&gt;
+    &lt;feature value="required"&gt;#dropMode&lt;/feature&gt;
+    &lt;feature value="required"&gt;#extent-region&lt;/feature&gt;
+    &lt;feature value="required"&gt;#extent-root&lt;/feature&gt;
+    &lt;feature value="required"&gt;#extent&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontFamily-generic&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontFamily-non-generic&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontFamily&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontSize-anamorphic&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontSize-isomorphic&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontSize&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontStyle-italic&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontStyle-oblique&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontStyle&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontWeight-bold&lt;/feature&gt;
+    &lt;feature value="required"&gt;#fontWeight&lt;/feature&gt;
+    &lt;feature value="required"&gt;#frameRate&lt;/feature&gt;
+    &lt;feature value="required"&gt;#frameRateMultiplier&lt;/feature&gt;
+    &lt;feature value="required"&gt;#layout&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length-cell&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length-em&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length-integer&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length-negative&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length-percentage&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length-pixel&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length-positive&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length-real&lt;/feature&gt;
+    &lt;feature value="required"&gt;#length&lt;/feature&gt;
+    &lt;feature value="required"&gt;#lineBreak-uax14&lt;/feature&gt;
+    &lt;feature value="required"&gt;#lineHeight&lt;/feature&gt;
+    &lt;feature value="required"&gt;#markerMode-continuous&lt;/feature&gt;
+    &lt;feature value="required"&gt;#markerMode-discontinuous&lt;/feature&gt;
+    &lt;feature value="required"&gt;#markerMode&lt;/feature&gt;
+    &lt;feature value="required"&gt;#metadata&lt;/feature&gt;
+    &lt;feature value="required"&gt;#nested-div&lt;/feature&gt;
+    &lt;feature value="required"&gt;#nested-span&lt;/feature&gt;
+    &lt;feature value="required"&gt;#opacity&lt;/feature&gt;
+    &lt;feature value="required"&gt;#origin&lt;/feature&gt;
+    &lt;feature value="required"&gt;#overflow-visible&lt;/feature&gt;
+    &lt;feature value="required"&gt;#overflow&lt;/feature&gt;
+    &lt;feature value="required"&gt;#padding-1&lt;/feature&gt;
+    &lt;feature value="required"&gt;#padding-2&lt;/feature&gt;
+    &lt;feature value="required"&gt;#padding-3&lt;/feature&gt;
+    &lt;feature value="required"&gt;#padding-4&lt;/feature&gt;
+    &lt;feature value="required"&gt;#padding&lt;/feature&gt;
+    &lt;feature value="required"&gt;#pixelAspectRatio&lt;/feature&gt;
+    &lt;feature value="required"&gt;#presentation&lt;/feature&gt;
+    &lt;feature value="required"&gt;#profile&lt;/feature&gt;
+    &lt;feature value="required"&gt;#showBackground&lt;/feature&gt;
+    &lt;feature value="required"&gt;#structure&lt;/feature&gt;
+    &lt;feature value="required"&gt;#styling-chained&lt;/feature&gt;
+    &lt;feature value="required"&gt;#styling-inheritance-content&lt;/feature&gt;
+    &lt;feature value="required"&gt;#styling-inheritance-region&lt;/feature&gt;
+    &lt;feature value="required"&gt;#styling-inline&lt;/feature&gt;
+    &lt;feature value="required"&gt;#styling-nested&lt;/feature&gt;
+    &lt;feature value="required"&gt;#styling-referential&lt;/feature&gt;
+    &lt;feature value="required"&gt;#styling&lt;/feature&gt;
+    &lt;feature value="required"&gt;#subFrameRate&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textAlign-absolute&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textAlign-relative&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textAlign&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textDecoration-over&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textDecoration-through&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textDecoration-under&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textDecoration&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textOrientation&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textOutline-blurred&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textOutline-unblurred&lt;/feature&gt;
+    &lt;feature value="required"&gt;#textOutline&lt;/feature&gt;
+    &lt;feature value="required"&gt;#tickRate&lt;/feature&gt;
+    &lt;feature value="required"&gt;#time-clock-with-frames&lt;/feature&gt;
+    &lt;feature value="required"&gt;#time-clock&lt;/feature&gt;
+    &lt;feature value="required"&gt;#time-offset-with-frames&lt;/feature&gt;
+    &lt;feature value="required"&gt;#time-offset-with-ticks&lt;/feature&gt;
+    &lt;feature value="required"&gt;#time-offset&lt;/feature&gt;
+    &lt;feature value="required"&gt;#timeBase-clock&lt;/feature&gt;
+    &lt;feature value="required"&gt;#timeBase-media&lt;/feature&gt;
+    &lt;feature value="required"&gt;#timeBase-smpte&lt;/feature&gt;
+    &lt;feature value="required"&gt;#timeContainer&lt;/feature&gt;
+    &lt;feature value="required"&gt;#timing&lt;/feature&gt;
+    &lt;feature value="required"&gt;#transformation&lt;/feature&gt;
+    &lt;feature value="required"&gt;#unicodeBidi&lt;/feature&gt;
+    &lt;feature value="required"&gt;#version&lt;/feature&gt;
+    &lt;feature value="required"&gt;#visibility-block&lt;/feature&gt;
+    &lt;feature value="required"&gt;#visibility-inline&lt;/feature&gt;
+    &lt;feature value="required"&gt;#visibility-region&lt;/feature&gt;
+    &lt;feature value="required"&gt;#visibility&lt;/feature&gt;
+    &lt;feature value="required"&gt;#wrapOption&lt;/feature&gt;
+    &lt;feature value="required"&gt;#writingMode-horizontal-lr&lt;/feature&gt;
+    &lt;feature value="required"&gt;#writingMode-horizontal-rl&lt;/feature&gt;
+    &lt;feature value="required"&gt;#writingMode-horizontal&lt;/feature&gt;
+    &lt;feature value="required"&gt;#writingMode-vertical&lt;/feature&gt;
+    &lt;feature value="required"&gt;#writingMode&lt;/feature&gt;
+    &lt;feature value="required"&gt;#zIndex&lt;/feature&gt;
+    &lt;!-- optional (voluntary) feature support --&gt;
+  &lt;/features&gt;
+  &lt;extensions xml:base="http://www.w3.org/ns/ttml/extension/"&gt;
+    &lt;!-- required (mandatory) extension support --&gt;
+    &lt;!-- optional (voluntary) extension support --&gt;
+  &lt;/extensions&gt;
+&lt;/profile&gt;
+
+</pre></div></div><div class="div2">
+<h3><a id="profile-ttml2-presentation"></a>G.2 TTML2 Presentation Profile</h3><p>The TTML2 Presentation Profile is intended to be used to
+express minimum compliance for presentation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This profile is a superset of the
+<a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml1/spec/ttml1.html#profile-dfxp-presentation">DFXP Presentation Profile</a>:
+it requires support for the <a href="#feature-version"><code>#version</code></a> feature.</p></div><div class="exampleInner"><pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
+&lt;!-- this file defines the "dfxp-presentation" profile of ttml --&gt;
+&lt;profile xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
+  &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+    &lt;!-- required (mandatory) feature support --&gt;
+    &lt;feature value="required"&gt;#content&lt;/feature&gt;
+    &lt;feature value="required"&gt;#core&lt;/feature&gt;
+    &lt;feature value="required"&gt;#presentation&lt;/feature&gt;
+    &lt;feature value="required"&gt;#profile&lt;/feature&gt;
+    &lt;feature value="required"&gt;#structure&lt;/feature&gt;
+    &lt;feature value="required"&gt;#time-offset&lt;/feature&gt;
+    &lt;feature value="required"&gt;#timing&lt;/feature&gt;
+    &lt;feature value="required"&gt;#version&lt;/feature&gt;
+    &lt;!-- optional (voluntary) feature support --&gt;
+    &lt;feature value="optional"&gt;#animation&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#backgroundColor-block&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#backgroundColor-inline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#backgroundColor-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#backgroundColor&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#bidi&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#border&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#cellResolution&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#clockMode-gps&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#clockMode-local&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#clockMode-utc&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#clockMode&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#color&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#direction&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#display-block&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#display-inline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#display-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#display&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#displayAlign&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#dropMode-dropNTSC&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#dropMode-dropPAL&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#dropMode-nonDrop&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#dropMode&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#extent-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#extent-root&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#extent&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontFamily-generic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontFamily-non-generic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontFamily&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontSize-anamorphic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontSize-isomorphic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontSize&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontStyle-italic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontStyle-oblique&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontStyle&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontWeight-bold&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontWeight&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#frameRate&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#frameRateMultiplier&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#layout&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-cell&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-em&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-integer&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-negative&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-percentage&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-pixel&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-positive&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-real&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#lineBreak-uax14&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#lineHeight&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#markerMode-continuous&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#markerMode-discontinuous&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#markerMode&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#metadata&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#nested-div&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#nested-span&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#opacity&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#origin&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#overflow-visible&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#overflow&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding-1&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding-2&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding-3&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding-4&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#pixelAspectRatio&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#showBackground&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-chained&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-inheritance-content&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-inheritance-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-inline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-nested&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-referential&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#subFrameRate&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textAlign-absolute&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textAlign-relative&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textAlign&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textDecoration-over&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textDecoration-through&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textDecoration-under&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textDecoration&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textOrientation&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textOutline-blurred&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textOutline-unblurred&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textOutline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#tickRate&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#time-clock-with-frames&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#time-clock&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#time-offset-with-frames&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#time-offset-with-ticks&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#timeBase-clock&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#timeBase-media&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#timeBase-smpte&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#timeContainer&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#transformation&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#unicodeBidi&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#visibility-block&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#visibility-inline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#visibility-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#visibility&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#wrapOption&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode-horizontal-lr&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode-horizontal-rl&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode-horizontal&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode-vertical&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#zIndex&lt;/feature&gt;
+  &lt;/features&gt;
+  &lt;extensions xml:base="http://www.w3.org/ns/ttml/extension/"&gt;
+    &lt;!-- required (mandatory) extension support --&gt;
+    &lt;!-- optional (voluntary) extension support --&gt;
+  &lt;/extensions&gt;
+&lt;/profile&gt;
+
+</pre></div></div><div class="div2">
+<h3><a id="profile-ttml2-transformation"></a>G.3 TTML2 Transformation Profile</h3><p>The TTML2 Transformation Profile is intended to be used to
+express minimum compliance for transformation processing.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>This profile is a superset of the
+<a href="https://dvcs.w3.org/hg/ttml/raw-file/default/ttml1/spec/ttml1.html#profile-dfxp-transformation">DFXP Transformation Profile</a>:
+it requires support for the <a href="#feature-version"><code>#version</code></a> feature.</p></div><div class="exampleInner"><pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
+&lt;!-- this file defines the "dfxp-transformation" profile of ttml --&gt;
+&lt;profile xmlns="http://www.w3.org/ns/ttml#parameter"&gt;
+  &lt;features xml:base="http://www.w3.org/ns/ttml/feature/"&gt;
+    &lt;!-- required (mandatory) feature support --&gt;
+    &lt;feature value="required"&gt;#content&lt;/feature&gt;
+    &lt;feature value="required"&gt;#core&lt;/feature&gt;
+    &lt;feature value="required"&gt;#profile&lt;/feature&gt;
+    &lt;feature value="required"&gt;#structure&lt;/feature&gt;
+    &lt;feature value="required"&gt;#time-offset&lt;/feature&gt;
+    &lt;feature value="required"&gt;#timing&lt;/feature&gt;
+    &lt;feature value="required"&gt;#transformation&lt;/feature&gt;
+    &lt;feature value="required"&gt;#version&lt;/feature&gt;
+    &lt;!-- optional (voluntary) feature support --&gt;
+    &lt;feature value="optional"&gt;#animation&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#backgroundColor-block&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#backgroundColor-inline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#backgroundColor-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#backgroundColor&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#bidi&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#border&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#cellResolution&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#clockMode-gps&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#clockMode-local&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#clockMode-utc&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#clockMode&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#color&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#direction&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#display-block&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#display-inline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#display-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#display&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#displayAlign&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#dropMode-dropNTSC&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#dropMode-dropPAL&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#dropMode-nonDrop&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#dropMode&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#extent-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#extent-root&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#extent&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontFamily-generic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontFamily-non-generic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontFamily&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontSize-anamorphic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontSize-isomorphic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontSize&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontStyle-italic&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontStyle-oblique&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontStyle&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontWeight-bold&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#fontWeight&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#frameRate&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#frameRateMultiplier&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#layout&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-cell&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-em&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-integer&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-negative&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-percentage&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-pixel&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-positive&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length-real&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#length&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#lineBreak-uax14&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#lineHeight&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#markerMode-continuous&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#markerMode-discontinuous&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#markerMode&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#metadata&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#nested-div&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#nested-span&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#opacity&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#origin&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#overflow-visible&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#overflow&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding-1&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding-2&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding-3&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding-4&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#padding&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#pixelAspectRatio&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#presentation&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#showBackground&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-chained&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-inheritance-content&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-inheritance-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-inline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-nested&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling-referential&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#styling&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#subFrameRate&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textAlign-absolute&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textAlign-relative&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textAlign&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textDecoration-over&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textDecoration-through&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textDecoration-under&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textDecoration&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textOrientation&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textOutline-blurred&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textOutline-unblurred&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#textOutline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#tickRate&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#time-clock-with-frames&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#time-clock&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#time-offset-with-frames&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#time-offset-with-ticks&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#timeBase-clock&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#timeBase-media&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#timeBase-smpte&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#timeContainer&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#unicodeBidi&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#visibility-block&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#visibility-inline&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#visibility-region&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#visibility&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#wrapOption&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode-horizontal-lr&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode-horizontal-rl&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode-horizontal&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode-vertical&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#writingMode&lt;/feature&gt;
+    &lt;feature value="optional"&gt;#zIndex&lt;/feature&gt;
+  &lt;/features&gt;
+  &lt;extensions xml:base="http://www.w3.org/ns/ttml/extension/"&gt;
+    &lt;!-- required (mandatory) extension support --&gt;
+    &lt;!-- optional (voluntary) extension support --&gt;
+  &lt;/extensions&gt;
+&lt;/profile&gt;
+
+</pre></div></div></div><div class="div1">
+<h2><a id="time-expression-semantics"></a>H Time Expression Semantics</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the semantics for interpreting time expressions in <a href="#terms-document-instance">document instances</a>.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The phrase <em>local real time</em> as used below is intended to model a virtual real time clock in the document processing context, where
+<em>local</em> means in the immediate proximity of the implementation of this processing context. The intent
+of defining relationships with this virtual clock is to establish a locally valid physical realization of time for didactic purposes.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The phrase <em>play rate</em> as used below is intended to model a (possibly variable) parameter in the document processing context wherein
+the rate of playback (or interpretation) of time may artificially dilated or narrowed, for example, when slowing down or speeding up the rate of
+playback of a <a href="#terms-related-media-object">related media object</a>. Without loss of generality, the following discussion assumes a fixed play(back) rate. In the case of
+variable play rates, appropriate adjustments may need to be made to the resulting computations.</p></div><div class="div2">
+<h3><a id="time-expression-semantics-clock"></a>H.1 Clock Time Base</h3><p>When operating with the <code>clock</code> time base, the following semantics apply for interpreting time expressions,
+as defined by <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, and their relationship to media time and local real time.</p><p>The clock time base <span class="strong"><code>C</code></span> is related to local real time <span class="strong"><code>R</code></span>
+expressed in an arbitrary (implementation defined) epoch <span class="strong"><code>E</code></span>
+as follows:</p><a id="clock-time-and-real-time"></a><table class="semantics"><caption>TTML Semantics – Clock Time and Real Time Relationship</caption><tbody><tr><td>
+<blockquote><p><br>
+<code>R = C + epochOffset + discontinuityOffset</code>
+<br><br>
+where <code>C ∈ ℜ</code>, <code>0 ≤ C &lt; ∞</code>, <code>C</code> in seconds since the most immediately prior midnight of the reference clock base;
+<br><br>
+<code>epochOffset ∈ ℜ</code>, <code>0 ≤ epochOffset &lt; ∞</code>, <code>epochOffset</code> in seconds, with 0 being the beginning
+of epoch <code>E</code>, and where the value of <code>epochOffset</code> is determined from the computed value of the <code>ttp:clockMode</code> parameter
+as follows:
+<br><br>
+(1) if <code>local</code>, then the difference between the local real time at the most immediately prior local midnight and the local real time
+at the beginning of epoch <code>E</code>, expressed in seconds;
+<br><br>
+(2) if <code>gps</code>, then the difference between the GPS time at the most immediately prior GPS midnight
+and the GPS time at the beginning of epoch <code>E</code>, expressed in seconds;
+<br><br>
+(3) if <code>utc</code>, then the difference between the UTC time at the most immediately prior UTC midnight
+and the UTC time at the beginning of epoch <code>E</code>, expressed in seconds;
+<br><br>
+<code>discontinuityOffset ∈ ℜ</code>, <code>−∞ &lt; discontinuityOffset &lt; ∞</code>, <code>discontinuityOffset</code> in seconds,
+and where the value of <code>discontinuityOffset</code> is equal to the sum of leap seconds (and fractions thereof) that have been added (or subtracted) since the
+most immediately prior midnight in the reference clock base;
+<br><br>
+and <code>epochOffset</code> and <code>discontinuityOffset</code> are determined once and only once prior to the beginning of the <a href="#terms-root-temporal-extent">root temporal extent</a> such that
+during the period between value determination and the beginning of the <a href="#terms-root-temporal-extent">root temporal extent</a> there occurs no local midnight or reference clock base discontinuity.
+<br></p></blockquote>
+</td></tr></tbody></table><p>Time value expressions, as denoted by a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, are related to
+clock time <span class="strong"><code>C</code></span> as follows:</p><a id="time-expressions-and-clock-time"></a><table class="semantics"><caption>TTML Semantics – Time Expressions and Clock Time Relationship</caption><tbody><tr><td>
+<blockquote><p><br>
+If a time expression uses the <em>clock-time</em> form or an <em>offset-time</em> form that doesn't use the ticks (<code>t</code>) metric, then:
+<br><br>
+<code>C = 3600 * hours + 60 * minutes + seconds</code>
+<br><br>
+where
+<code>hours</code>,
+<code>minutes</code>,
+<code>seconds</code> components are extracted from time expression if present, or zero if not present.
+<br><br>
+Otherwise, if a time expression uses an <em>offset-time</em> form that uses the ticks (<code>t</code>) metric, then:
+<br><br>
+<code>C = ticks / tickRate</code>
+<br></p></blockquote>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>The <em>frames</em> and <em>sub-frames</em> terms and the frames (<code>f</code>) metric of time expressions do not apply when using
+the <code>clock</code> time base.</p></div><p>The clock time base <span class="strong"><code>C</code></span> is independent of media time <span class="strong"><code>M</code></span>:</p><a id="clock-time-and-media-time"></a><table class="semantics"><caption>TTML Semantics – Clock Time and Media Time Relationship</caption><tbody><tr><td>
+<blockquote><p><br>
+<code>M ¬∝ C</code>
+<br></p></blockquote>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>That is to say, timing is disconnected from (not necessarily proportional to) media time when
+the <code>clock</code> time base is used. For example, if the media play rate is zero (0), media playback is suspended; however, timing coordinates
+will continue to advance according to the natural progression of clock time in direct proportion to the reference clock base. Furthermore, if the media play rate changes
+during playback, presentation timing is not affected.
+</p></div></div><div class="div2">
+<h3><a id="time-expression-semantics-media"></a>H.2 Media Time Base</h3><p>When operating with the <code>media</code> time base, the following semantics apply for interpreting time expressions,
+as defined by <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, and their relationship to media time and local real time.</p><div class="issue"><p class="prefix"><a id="issue-306"></a><b>Issue (issue-306):</b></p><p class="prefix"><b>Fractional Time Expressions</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/306">http://www.w3.org/AudioVideo/TT/tracker/issues/306</a></p><p>Augment syntax to cover fractional time expressions.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>The media time base <span class="strong"><code>M</code></span> is related to local real time <span class="strong"><code>R</code></span>
+expressed in an arbitrary (implementation defined) epoch <span class="strong"><code>E</code></span> as follows:</p><a id="media-time-and-real-time"></a><table class="semantics"><caption>TTML Semantics – Media Time and Real Time Relationship</caption><tbody><tr><td>
+<blockquote><p><br>
+<code>R = playRate * M + epochOffset</code>
+<br><br>
+where <code>M ∈ ℜ</code>, <code>0 ≤ M &lt; ∞</code>, <code>M</code> in seconds, with 0 corresponding to the beginning of the <a href="#terms-root-temporal-extent">root temporal extent</a>;
+<br><br>
+<code>playRate ∈ ℜ</code>, <code>−∞ &lt; playRate &lt; ∞</code>, <code>playRate</code> is unit-less, and where the value of
+<code>playRate</code> is determined by the document processing context;
+<br><br>
+and <code>epochOffset ∈ ℜ</code>, <code>0 ≤ epochOffset &lt; ∞</code>, <code>epochOffset</code> in seconds, with 0 corresponding to the beginning of
+an epoch <code>E</code>, and where the value of <code>epochOffset</code> is the difference between the local real time at the beginning of the
+<a href="#terms-root-temporal-extent">root temporal extent</a> and the local real time at the the beginning of epoch <code>E</code>, expressed in seconds.
+</p></blockquote>
+</td></tr></tbody></table><p>Time value expressions, as denoted by a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, are related to
+media time <span class="strong"><code>M</code></span> in accordance to the
+<code>ttp:frameRate</code>, <code>ttp:subFrameRate</code>, and <code>ttp:frameRateMultipler</code> parameters as follows:</p><a id="time-expressions-and-media-time"></a><table class="semantics"><caption>TTML Semantics – Time Expressions and Media Time Relationship</caption><tbody><tr><td>
+<blockquote><p><br>
+If a time expression uses a <em>clock-time</em> form or an <em>offset-time</em> form that doesn't use the ticks (<code>t</code>) metric, then:
+<br><br>
+<code>
+M = referenceBegin + 3600 * hours + 60 * minutes + seconds + ((frames + (subFrames / subFrameRate)) / effectiveFrameRate)
+</code>
+<br><br>
+where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
+parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
+timed element exists, then <code>referenceBegin</code>
+is the media time that corresponds to the beginning of the nearest ancestor time container or
+zero (0) if this time container is the <a href="#terms-root-temporal-extent">root temporal extent</a>; otherwise, if sequential and a prior sibling
+timed element exists, then <code>referenceBegin</code> is the media time that corresponds to the active end of the
+immediate prior sibling timed element;
+<br><br>
+the <code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
+are extracted from time expression if present, or zero if not present;
+<br><br>
+<code>subFrameRate</code> is the computed value of the <code>ttp:subFrameRate</code> parameter;
+<br><br>
+and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
+<code>frameRate</code> is the computed value of the <code>ttp:frameRate</code> parameter and
+<code>frameRateMultipler</code> is the computed value of the <code>ttp:frameRateMultiplier</code> parameter.
+<br><br>
+Otherwise, if a time expression uses an <em>offset-time</em> form that uses the ticks (<code>t</code>) metric, then:
+<br><br>
+<code>
+M = referenceBegin + ticks / tickRate
+</code>
+<br><br>
+where <code>referenceBegin</code> is as described above;
+<br><br>
+the <code>ticks</code> component is extracted from time expression;
+<br><br>
+and <code>tickRate</code> is the computed value of the <code>ttp:tickRate</code> parameter;
+<br></p></blockquote>
+</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>If the computed <code>frameRateMultipler</code> ratio is not integral, then <code>effectiveFrameRate</code> will be a non-integral rational.</p></div><div class="note"><p class="prefix"><b>Note:</b></p><p>The begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a> is related to the begin time of a
+<a href="#terms-related-media-object">related media object</a> in accordance with the computed value of the
+<a href="#parameter-attribute-mediaOffset"><code>ttp:mediaOffset</code></a> parameter property.</p></div></div><div class="div2">
+<h3><a id="time-expression-semantics-smpte"></a>H.3 SMPTE Time Base</h3><p>When operating with the <code>smpte</code> time base, the following semantics apply for interpreting time expressions,
+as defined by <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, and their relationship to media time and local real time.</p><div class="issue"><p class="prefix"><a id="issue-322"></a><b>Issue (issue-322):</b></p><p class="prefix"><b>Incorrect Expression for NTSC Drop Mode</b></p><p><b>Source</b>: <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/322">http://www.w3.org/AudioVideo/TT/tracker/issues/322</a></p><p>Correct formula for NTSC drop mode calculation.</p><p class="prefix"><b>Resolution:</b></p><p>None recorded.</p></div><p>If the computed value of the <code>ttp:markerMode</code> parameter is <code>discontinuous</code>, then there is no direct relationship between
+time expressions and media time <span class="strong"><code>M</code></span> or local real time <span class="strong"><code>R</code></span>. In
+this case, time expressions refer to synchronization events (markers) emitted by the <a href="#terms-document-processing-context">document processing context</a>
+when <a href="#terms-smpte-time-code">smpte time codes</a>
+are encountered in the <a href="#terms-related-media-object">related media object</a>.</p><p>Otherwise, if the computed value of the <code>ttp:markerMode</code> parameter is <code>continuous</code>, then the relationships between time expressions and
+local real time and media time are as described below in terms of a <a href="#terms-synthetic-smpte-document-syncbase">synthetic smpte document syncbase</a>, here referred to as the
+SMPTE time base <span class="strong"><code>S</code></span>.</p><a id="time-expressions-and-smpte-time"></a><table class="semantics"><caption>TTML Semantics – Time Expressions and SMPTE Time Relationship</caption><tbody><tr><td>
+<blockquote><p><br>
+<code>S = (countedFrames - droppedFrames + (subFrames / subFrameRate)) / effectiveFrameRate</code>
+<br><br>where<br><br>
+<code>countedFrames = (3600 * hours + 60 * minutes + seconds) * frameRate + frames</code>
+<br><br>
+<code>hours</code>, <code>minutes</code>, <code>seconds</code>, <code>frames</code>, <code>subFrames</code> components
+are extracted from time expression if present, or zero if not present;
+<br><br>
+<code>droppedFrames</code> is computed as follows:
+<br><br>
+1. let <em>dropMode</em> be the computed value of the <code>ttp:dropMode</code> parameter;
+<br><br>
+2. if <em>dropMode</em> is <code>dropNTSC</code>, let
+<code>droppedFrames = (hours * 54 + floor(minutes - minutes/10)) * 2</code>;
+<br><br>
+3. otherwise, if <em>dropMode</em> is <code>dropPAL</code>, let
+<code>droppedFrames = (hours * 27 + floor(minutes/2 - minutes/20)) * 4</code>;
+<br><br>
+4. otherwise, let
+<code>droppedFrames = 0</code>;
+<br><br>
+<code>frameRate</code> is the computed value of the <code>ttp:frameRate</code> parameter;
+<br><br>
+<code>subFrameRate</code> is the computed value of the <code>ttp:subFrameRate</code> parameter;
+<br><br>
+and <code>effectiveFrameRate</code> (in frames per second) is <code>frameRate * frameRateMultipler</code> where
+<code>frameRate</code> is the computed value of the <code>ttp:frameRate</code> parameter and
+<code>frameRateMultipler</code> is the computed value of the <code>ttp:frameRateMultiplier</code> parameter.
+<br><br>
+Notwithstanding the above, if a time expression contains a frame code that is designated as
+dropped according to <a href="#parameter-attribute-dropMode"><b>7.2.3 ttp:dropMode</b></a>, then that time expression
+must be considered to be invalid for purposes of validation assessment.
+<br></p></blockquote>
+</td></tr></tbody></table><p>The SMPTE time base <span class="strong"><code>S</code></span> is related to the media time base <span class="strong"><code>M</code></span> as follows:</p><a id="smpte-time-and-media-time"></a><table class="semantics"><caption>TTML Semantics – SMPTE Time and Media Time Relationship</caption><tbody><tr><td>
+<blockquote><p><br>
+<code>M = referenceBegin + S</code>
+<br><br>
+where <code>referenceBegin</code> is determined according to whether the nearest ancestor time container employs
+parallel (<code>par</code>) or sequential (<code>seq</code>) semantics: if parallel or if sequential and no prior sibling
+timed element exists, then <code>referenceBegin</code>
+is the SMPTE time that corresponds to the beginning of the nearest ancestor time container or
+zero (0) if this time container is the <a href="#terms-root-temporal-extent">root temporal extent</a>; otherwise, if sequential and a prior sibling
+timed element exists, then <code>referenceBegin</code> is the SMPTE time that corresponds to the active end of the
+immediate prior sibling timed element;
+<br></p></blockquote>
+</td></tr></tbody></table><p>Given the derived media time base as described above, then 
+media time base <span class="strong"><code>M</code></span> is related to the local real time <span class="strong"><code>R</code></span>
+as described in <a href="#time-expression-semantics-media"><b>H.2 Media Time Base</b></a> above.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a> is related to the begin time of a
+<a href="#terms-related-media-object">related media object</a> in accordance with the computed value of the
+<a href="#parameter-attribute-mediaOffset"><code>ttp:mediaOffset</code></a> parameter property.</p></div></div></div><div class="div1">
+<h2><a id="isd"></a>I Intermediate Document Syntax</h2><p><em>This appendix is normative.</em></p><p>This appendix specifies the syntactic elements and structure of a
+<a href="#terms-timed-text-intermediate-document">timed text intermediate document</a>.
+An ISD instance may be represented as a standalone document instance or
+in a collection represented as an ISD Sequence instance.</p><p>All ISD related vocabulary is defined in the TTML ISD Namespace, defined here as <code>http://www.w3.org/ns/ttml#isd</code>,
+where the recommended prefix is <code>isd</code>.</p><p>A TTML <a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>, in short, an <em>ISD</em> or <em>ISD instance</em>,
+represents a discrete, temporally non-overlapping interval, an <em>ISD interval</em>,
+of a source TTML document where, except for non-discrete animation, all content, styling, and layout information remains static within that interval.
+In particular, the timing hierarchy of a TTML document is flattened and then sub-divided into temporally non-overlapping intervals, where each such
+interval defines a static view of the source TTML document within that interval, and where that static view is represented as an ISD instance.
+A concrete, standalone instance of a TTML
+<a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a> must specify an
+<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element as its root document element. When an instance of a
+<a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a> is included in a
+<a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a> instance, then the ISD instance is represented
+by an <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> child element of the root 
+<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>An ISD instance may contain one or more animate elements that denote continuous animation within the associated interval. Continuously animated styles are sub-divided across
+ISD interval boundaries such that their step-wise concatenation expresses an equivalent continuous animation over any intersecting ISD interval(s).</p></div><p>A TTML <a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a> represents a collection
+of temporally non-overlapping <a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a> instances ordered according
+to their begin times. A concrete instance of a TTML
+<a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a> must specify an
+<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element as its root document element.</p><div class="div2">
+<h3><a id="isd-vocabulary"></a>I.1 ISD Vocabulary</h3><div class="div3">
+<h4><a id="isd-vocabulary-sequence"></a>I.1.1 isd:sequence</h4><p>The <code>isd:sequence</code> element serves as the root document element of an <a href="#terms-intermediate-synchronic-document-sequence">Intermediate
+Synchronic Document Sequence</a>  document.</p><p>The <code>isd:sequence</code> element accepts as its children zero or more elements in the
+<a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or one <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element,
+followed by zero or more <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> elements.</p><p>Child <code>isd:isd</code> elements must be ordered in accordance to the media time equivalent of their
+begin time; furthermore, the temporal intervals of any two child <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> elements must not overlap (in time).</p><a id="elt-syntax-isd-sequence"></a><table class="syntax"><caption>XML Representation – Element Information Item: isd:sequence</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;isd:sequence
+  size = <a href="http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger">xsd:nonNegativeInteger</a>
+  version = <a href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</a>
+  <a href="#content-attribute-xml-lang"><span class="reqattr">xml:lang</span></a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  {<em>any attribute in the <a href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</a></em>}&gt;
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#profile-vocabulary-profile">ttp:profile</a>?, <a href="#isd-vocabulary-isd">isd:isd</a>*
+&lt;/isd:sequence&gt;
+</pre></div>
+</td></tr></tbody></table><p>If the <code>size</code> attribute is specified, then it must be a non-negative integer corresponding to the number of
+<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> child elements.
+If not specified, then the size must be considered to be <em>indefinite</em>, unless and until the
+<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element is terminated, in which case the size
+may be determined by inspection.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The <code>size</code> attribute would normally be omitted in the case of real time captioning.</p></div><p>If the <code>version</code> attribute is specified, then it must be a positive integer corresponding to the version of this
+<a href="#terms-intermediate-synchronic-document-syntax">Intermediate Synchronic Document Syntax</a> specification used in authoring
+the ISD sequence document. If specified, the numeric value must be greater than or equal to two (2). If not specified, then the version must be
+consider to be equal to two (2). The version associated with this
+<a href="#terms-intermediate-synchronic-document-sequence-syntax">Intermediate Synchronic Document Sequence Syntax</a> specification is two (2).</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The ISD abstraction referred to or implied by <a href="#ttml1">[TTML1]</a> §9.3.2 was not concretely defined by that specification. Here we reserve version one (1)
+for informal discussion of that earlier abstraction and its various (non-standardized) realizations.</p></div><p>An <a href="#content-attribute-xml-lang"><code>xml:lang</code></a> attribute must be specified on the
+<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element.
+If its value is empty, it signifies that there is no default language that applies
+to the content within the <a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a>. Otherwise,
+the specified value denotes the default language that applies to each constituent
+<a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>.</p><p>One or more parameter properties may be specified from the restricted parameter attribute set enumerated in <a href="#isd-parameter-attribute-set"><b>I.2 ISD Parameter Attribute Set</b></a>.
+If specified, then they apply globally to each constituent <a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>.</p><p>If a child <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element is present,
+then that <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element must satisfy the following constraints:</p><ul><li><p>no <code>combine</code> attribute is specified;</p></li><li><p>no <code>designator</code> attribute is specified;</p></li><li><p>no <code>type</code> attribute is specified;</p></li><li><p>no <code>use</code> attribute is specified;</p></li><li><p>no descendant element is a <code>ttp:profile</code> element;</p></li><li><p>no descendant <code>ttp:feature</code> element specifies a <code>value</code> attribute with the value <code>prohibited</code>;</p></li><li><p>no descendant <code>ttp:extension</code> element specifies a <code>value</code> attribute with the value <code>prohibited</code>.</p></li></ul><p>Furthermore, such a child <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element must specify a profile that is equivalent to the combined
+<a href="#terms-processor-profile">processor profile</a> of the source TTML document having fetched all externally referenced profile documents.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>The intent of permitting a single <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> to be specified in an
+<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> is to provide a simplified mechanism to declare
+processor profile requirements that must be met in order to process the document (in the absence of an end-user override).</p></div></div><div class="div3">
+<h4><a id="isd-vocabulary-isd"></a>I.1.2 isd:isd</h4><p>The <code>isd:isd</code> element serves either as (1) the root document element of a standalone <a href="#terms-intermediate-synchronic-document">Intermediate
+Synchronic Document</a> or (2) as a child of an <a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element of a
+<a href="#terms-intermediate-synchronic-document-sequence">Intermediate Synchronic Document Sequence</a> document.</p><p>The <code>isd:isd</code> element accepts as its children zero or more elements in the
+<a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or one <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element,
+followed by zero or more <a href="#isd-vocabulary-css"><code>isd:css</code></a> elements,
+followed by zero or more <a href="#isd-vocabulary-region"><code>isd:region</code></a> elements.</p><a id="elt-syntax-isd"></a><table class="syntax"><caption>XML Representation – Element Information Item: isd:isd</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;isd:isd
+  <a href="#timing-attribute-begin"><span class="reqattr">begin</span></a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  <a href="#timing-attribute-end"><span class="reqattr">end</span></a> = <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>
+  version = <a href="http://www.w3.org/TR/xmlschema-2/#positiveInteger">xsd:positiveInteger</a>
+  <a href="#content-attribute-xml-lang">xml:lang</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  {<em>any attribute in the <a href="#isd-parameter-attribute-set">ISD Parameter Attribute Set</a></em>}&gt;
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#profile-vocabulary-profile">ttp:profile</a>?, <a href="#isd-vocabulary-css">isd:css</a>*, <a href="#isd-vocabulary-region">isd:region</a>*
+&lt;/isd:isd&gt;
+</pre></div>
+</td></tr></tbody></table><p>A <code>begin</code> attribute must be specified, the value of which must take the <em>offset-time</em> form of
+a <a href="#timing-value-timeExpression">&lt;timeExpression&gt;</a>, and, further, is restricted to use a metric of
+<code>s</code> (seconds),
+<code>f</code> (frames),
+<code>t</code> (ticks), or may omit the metric, in which case <code>s</code> seconds is implied. This
+begin time is expressed as an offset from the begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a>
+of the source TTML document from which this <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element was derived.</p><p>An <code>end</code> attribute must be similarlly specified, where the same constraints apply.
+This end time is expressed as an offset from the begin time of the <a href="#terms-root-temporal-extent">root temporal extent</a>
+of the source TTML document from which this <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element was derived.</p><div class="note"><p class="prefix"><b>Note:</b></p><p>Expressed in the terminology of <a href="#smil3">[SMIL 3.0]</a>, the values of these <code>begin</code> and <code>end</code> attributes
+correspond to the resolved begin and end times of the <em>active duration</em> with respect to the <em>document begin</em>.</p></div><p>An <a href="#content-attribute-xml-lang"><code>xml:lang</code></a> attribute must be specified on the
+<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element if it is a standalone <a href="#terms-intermediate-synchronic-document">Intermediate
+Synchronic Document</a> document; otherwise, it may be specified, and should be specified if the default language of the 
+<a href="#isd-vocabulary-sequence"><code>isd:isd</code></a> element differs from the default language of its
+parent <a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element.
+If its value is empty, it signifies that there is no default language that applies
+to the content within the <a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>. Otherwise,
+the specified value denotes the default language that applies.</p><p>The <code>version</code> attribute follows the syntax and semantics of the same named attribute on the
+<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element type. The <code>version</code>
+attribute must not be specified on an <a href="#isd-vocabulary-isd">isd:isd</a> element that is not
+a root document element, i.e., is a child element of an <a href="#isd-vocabulary-sequence">isd:sequence</a> element.</p><p>A child <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element may be present if the
+<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element is a standalone <a href="#terms-intermediate-synchronic-document">Intermediate
+Synchronic Document</a> document, in which case the same constraints and semantics apply as specified in <a href="#isd-vocabulary-sequence"><b>I.1.1 isd:sequence</b></a>;
+otherwise, if not a standalone document, a child <a href="#profile-vocabulary-profile"><code>ttp:profile</code></a> element must not be present.</p></div><div class="div3">
+<h4><a id="isd-vocabulary-css"></a>I.1.3 isd:css</h4><p>The <code>isd:css</code> element is used to represent a unique computed style set of some collection of elements
+that share the same set of computed styles. In particular, for each
+element <em>E</em> in the source TTML document which is selected and copied into a
+<a href="#isd-vocabulary-region"><code>isd:region</code></a> element of a given
+<a href="#terms-intermediate-synchronic-document">Intermediate Synchronic Document</a>, the computed style
+set of <em>E</em>, <em>CSS(E)</em>, is determined, and, if that <em>CSS(E)</em> is not already specified
+by an existing <code>isd:css</code> element, then it is assigned a unique identifier and instantiated as a new
+<code>isd:css</code> element.</p><p>The <code>isd:css</code> element accepts as its children zero or more elements in the
+<a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group.</p><a id="elt-syntax-isd-style"></a><table class="syntax"><caption>XML Representation – Element Information Item: isd:css</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;isd:css
+  <a href="#content-attribute-xml-id"><span class="reqattr">xml:id</span></a> = ID
+  {<em>any attribute in TT Style namespace</em>}
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*
+&lt;/isd:css&gt;
+</pre></div>
+</td></tr></tbody></table><p>For each arbitrary pair of <code>isd:css</code> child elements of an
+<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element,
+<em>S1</em> and <em>S2</em>, the set of specified styles of <em>S1</em> must
+not be the same as the set of specified styles of <em>S2</em>. For the purpose of comparing two
+sets of specified styles, the styles must be placed into a canonical order and then compared item
+by item for value equality, where the canonical order is in accordance to the qualified attribute name
+order, where each qualified name consists of a tuple <code>&lt;namespace URL, local name&gt;</code>,
+and such tuples are compared component-wise by case-sensitive lexical string order.</p></div><div class="div3">
+<h4><a id="isd-vocabulary-region"></a>I.1.4 isd:region</h4><p>The <code>isd:region</code> element is used to represent a layout and presentation region
+and the content selected into that region, where that content takes the form of a
+<a href="#document-structure-vocabulary-body">body</a> element and its descendant TTML content elements.</p><p>The <code>isd:region</code> element accepts as its children zero or more elements in the
+<a href="#element-vocab-group-metadata"><code>Metadata.class</code></a> element group,
+followed by zero or more <a href="#animation-vocabulary-animate"><code>animate</code></a> elements,
+followed by exactly one <a href="#document-structure-vocabulary-body"><code>body</code></a> element.</p><a id="elt-syntax-isd-region"></a><table class="syntax"><caption>XML Representation – Element Information Item: isd:region</caption><tbody><tr><td>
+<div class="exampleInner"><pre>
+&lt;isd:region
+  <a href="#style-attribute-style">style</a> = IDREF
+  <a href="#metadata-attribute-role">ttm:role</a> = <a href="http://www.w3.org/TR/xmlschema-2/#string">xsd:string</a>
+  <a href="#content-attribute-xml-id"><span class="reqattr">xml:id</span></a> = ID
+  {<em>any attribute not in default or any TT namespace</em>}&gt;
+  <em>Content:</em> <a href="#element-vocab-group-metadata">Metadata.class</a>*, <a href="#animation-vocabulary-animate">animate</a>*, <a href="#document-structure-vocabulary-body">body</a>
+&lt;/isd:region&gt;
+</pre></div>
+</td></tr></tbody></table><p>If the computed style set of the region represented by the <code>isd:region</code> element is not the
+set of initial style values that apply to <a href="#layout-vocabulary-region"><code>region</code></a>, then a
+<code>style</code> attribute must be specified which references an <a href="#isd-vocabulary-css"><code>isd:css</code></a> element that specifies the
+region's computed style set.</p><p>The following constraints apply to the <a href="#document-structure-vocabulary-body"><code>body</code></a> element
+and its descendant elements:</p><ul><li><p>no <code>animate</code> attribute is specified;</p></li><li><p>no <code>begin</code> attribute is specified;</p></li><li><p>no <code>dur</code> attribute is specified;</p></li><li><p>no <code>end</code> attribute is specified;</p></li><li><p>no <code>region</code> attribute is specified;</p></li><li><p>no <code>timeContainer</code> attribute is specified;</p></li><li><p>no attribute in the TT Style namespace is specified;</p></li><li><p>no <a href="#animation-vocabulary-set">set</a> element is present;</p></li><li><p>no significant text node, i.e., text node in a #PCDATA context, is not contained in a 
+<a href="#content-vocabulary-span"><code>span</code></a> element that contains no other child.</p></li></ul><p>In addition, for the <a href="#document-structure-vocabulary-body"><code>body</code></a> element <em>B</em> and
+each of its descendant content elements <em>C</em>, if the computed style set of <em>B</em> or each <em>C</em> is
+not equal to the computed style set of its parent element, then that element, <em>B</em> or <em>C</em>, must specify a <code>style</code>
+attribute that references an <a href="#isd-vocabulary-css"><code>isd:css</code></a> element that specifies the
+element's computed style set.</p></div></div><div class="div2">
+<h3><a id="isd-parameter-attribute-set"></a>I.2 ISD Parameter Attribute Set</h3><p>The following subset of the defined <a href="#attribute-vocab-group-parameters">Parameter Attributes</a>
+are available for use with an
+<a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> or
+<a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element as described above:</p><ul><li><p><a href="#parameter-attribute-cellResolution">ttp:cellResolution</a></p></li><li><p><a href="#parameter-attribute-frameRate">ttp:frameRate</a></p></li><li><p><a href="#parameter-attribute-frameRateMultiplier">ttp:frameRateMultipler</a></p></li><li><p><a href="#parameter-attribute-mediaOffset">ttp:mediaOffset</a></p></li><li><p><a href="#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</a></p></li><li><p><a href="#parameter-attribute-subFrameRate">ttp:subFrameRate</a></p></li><li><p><a href="#parameter-attribute-tickRate">ttp:tickRate</a></p></li></ul></div><div class="div2">
+<h3><a id="isd-interchange"></a>I.3 ISD Interchange</h3><p>A concrete document instance that employs the <a href="#isd">Intermediate Synchronic Document Syntax</a> must be
+encoded as a well-formed <a href="#xml10">[XML 1.0]</a> document using the UTF-8 character encoding. Furthermore, such a document must specify
+an <a href="#isd-vocabulary-sequence"><code>isd:sequence</code></a> element or
+an <a href="#isd-vocabulary-isd"><code>isd:isd</code></a> element as the root document element.</p><p>When a resource consisting of a concrete ISD Sequence or ISD instance is interchanged and a media type is used to identify the content type
+of that resource, then the media type <code>application/ttml+xml</code> should be used, about which see <a href="#ttml1">[TTML1]</a> Appendix C.
+If this media type is used, the optional <code>profile</code> parameter must not be specified, or, if specified, must be ignored by a processor.</p></div><div class="div2">
+<h3><a id="isd-examples"></a>I.4 ISD Examples</h3><p><em>This sub-section is non-normative.</em></p><table border="1" class="ednote" summary="Editorial note: Add ISD Examples"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Add ISD Examples</b></td><td align="right" valign="top">2014-09-22</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Add worked out examples of ISD Sequence and ISD document instances.</td></tr></table></div></div><div class="div1">
+<h2><a id="references"></a>J References</h2><p><em>This appendix is normative.</em></p><dl><dt class="label"><a id="css2"></a>CSS2</dt><dd>Bert Bos et al.,
+<a href="http://www.w3.org/TR/2011/REC-CSS2-20110607/"><cite>Cascading
+Style Sheets, Level 2 Revision 1</cite></a>, W3C Recommendation, 07 June 2011.
+(See <a href="http://www.w3.org/TR/2011/REC-CSS2-20110607/">http://www.w3.org/TR/2011/REC-CSS2-20110607/</a>.)
+</dd><dt class="label"><a id="css3-color"></a>CSS3 Color</dt><dd>Tantek Çelik and Chris Lilley,
+<a href="http://www.w3.org/TR/2011/REC-css3-color-20110607/"><cite>CSS Color
+Module Level 3</cite></a>, W3C Recommendation, 07 June 2011. (See
+<a href="http://www.w3.org/TR/2011/REC-css3-color-20110607/">http://www.w3.org/TR/2011/REC-css3-color-20110607/</a>.)
+</dd><dt class="label"><a id="data-encodings"></a>Data Encodings</dt><dd>S. Josefsson,
+<a href="http://www.rfc-editor.org/rfc/rfc4648.txt"><cite>The Base16, Base32, and Base64 Data Encodings</cite></a>,
+RFC 4648, October 2006, IETF. (See
+<a href="http://www.rfc-editor.org/rfc/rfc4648.txt">http://www.rfc-editor.org/rfc/rfc4648.txt</a>.)
+</dd><dt class="label"><a id="gps"></a>GPS</dt><dd>
+<a href="http://www.gps.gov/technical/"><cite>Global
+Positioning System</cite></a>, US Air Force.
+(See
+<a href="http://www.gps.gov/technical/">http://www.gps.gov/technical/</a>.)
+</dd><dt class="label"><a id="html5"></a>HTML5</dt><dd>Ian Hickson et al.,
+<a href="http://www.w3.org/TR/2014/REC-html5-20141028/"><cite>HTML5 A vocabulary and associated APIs for HTML and XHTML</cite></a>,
+W3C Recommendation, 28 October 2014. (See
+<a href="http://www.w3.org/TR/2014/REC-html5-20141028/">http://www.w3.org/TR/2014/REC-html5-20141028/</a>.)
+</dd><dt class="label"><a id="media-queries"></a>Media Queries</dt><dd>Florian Rivoal,,
+<a href="http://www.w3.org/TR/2012/REC-css3-mediaqueries-20120619/"><cite>Media Queries</cite></a>, W3C Recommendation, 19 June 2012. (See
+<a href="http://www.w3.org/TR/2012/REC-css3-mediaqueries-20120619/">http://www.w3.org/TR/2012/REC-css3-mediaqueries-20120619/</a>.)
+</dd><dt class="label"><a id="mime"></a>MIME</dt><dd>Ned Freed and Nathaniel Borenstein,  
+<a href="http://www.rfc-editor.org/rfc/rfc2045.txt"><cite>Multipurpose Internet
+Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite></a>,
+RFC 2045, November 1996, IETF.(See
+<a href="http://www.rfc-editor.org/rfc/rfc2045.txt">http://www.rfc-editor.org/rfc/rfc2045.txt</a>.)
+</dd><dt class="label"><a id="media-types"></a>MIME Media Types</dt><dd>Ned Freed and Nathaniel Borenstein,  
+<a href="http://www.rfc-editor.org/rfc/rfc2046.txt"><cite>Multipurpose Internet
+Mail Extensions (MIME) Part Two: Media Types</cite></a>,
+RFC 2046, November 1996, IETF.(See
+<a href="http://www.rfc-editor.org/rfc/rfc2046.txt">http://www.rfc-editor.org/rfc/rfc2046.txt</a>.)
+</dd><dt class="label"><a id="rng"></a>RELAX NG</dt><dd>ISO/IEC 19757-2,
+<a href="http://www.iso.org/"><cite>Information technology – Document
+Schema Definition Language (DSDL) – Part 2: Regular-grammar-based validation – RELAX NG</cite></a>,
+International Organization for Standardization (ISO).
+</dd><dt class="label"><a id="ruby"></a>Ruby</dt><dd>Masayasu Ishikawa et al.,
+<a href="http://www.w3.org/TR/2001/REC-ruby-20010531/"><cite>Ruby Annotation</cite></a>
+W3C Recommendation, 31 May 2001.
+(See <a href="http://www.w3.org/TR/2001/REC-ruby-20010531/">http://www.w3.org/TR/2001/REC-ruby-20010531/</a>.)
+</dd><dt class="label"><a id="smil3"></a>SMIL 3.0</dt><dd>Dick Bultermann, et al.,
+<a href="http://www.w3.org/TR/2008/REC-SMIL3-20081201/"><cite>Synchronized
+Multimedia Integration Language (SMIL 3.0)</cite></a>,
+W3C Recommendation, 1 December 2008. (See
+<a href="http://www.w3.org/TR/2008/REC-SMIL3-20081201/">http://www.w3.org/TR/2008/REC-SMIL3-20081201/</a>.)
+</dd><dt class="label"><a id="smpte12m"></a>SMPTE 12M</dt><dd>ANSI/SMPTE 12M,
+<a href="https://www.smpte.org/"><cite>Television, Audio and Film –
+Time and Control Code</cite></a>, SMPTE Standard.
+</dd><dt class="label"><a id="srgb"></a>SRGB</dt><dd>IEC 61966-2-1,
+<a href="http://www.iec.ch/"><cite>Multimedia
+systems and equipment – Colour measurement and management
+– Part 2-1: Colour management – Default RGB colour space
+– sRGB</cite></a>, International Electrotechnical
+Commission (IEC).
+</dd><dt class="label"><a id="svg11"></a>SVG 1.1</dt><dd>Erik Dahlström et al., Eds.,
+<a href="http://www.w3.org/TR/2011/REC-SVG11-20110816/"><cite>Scalable
+Vector Graphics (SVG) 1.1 Second Edition</cite></a>, W3C Recommendation, 16
+August 2011. (See
+<a href="http://www.w3.org/TR/2011/REC-SVG11-20110816/">http://www.w3.org/TR/2011/REC-SVG11-20110816/</a>.)
+</dd><dt class="label"><a id="uaag"></a>UAAG</dt><dd>Ian Jacobs, Jon Gunderson, and Eric Hansen, Eds.,
+<a href="http://www.w3.org/TR/2002/REC-UAAG10-20021217/"><cite>User
+Agent Accessibility Guidelines 1.0</cite></a>, W3C Recommendation, 17
+December 2002. (See
+<a href="http://www.w3.org/TR/2002/REC-UAAG10-20021217/">http://www.w3.org/TR/2002/REC-UAAG10-20021217/</a>.)
+</dd><dt class="label"><a id="uax14"></a>UAX14</dt><dd>Asmus Freytag, <a href="http://www.unicode.org/reports/tr14/tr14-17.html"><cite>Line Breaking
+Properties</cite></a>, Unicode Consortium, 29 August 2005. (See
+<a href="http://www.unicode.org/reports/tr14/tr14-17.html">http://www.unicode.org/reports/tr14/tr14-17.html</a>.)
+</dd><dt class="label"><a id="uri"></a>URI</dt><dd>T. Berner-Lee, R. Fielding, and L. Masinter,
+<a href="http://www.rfc-editor.org/rfc/rfc2396.txt"><cite>Uniform Resource Identifiers (URI): Generic Syntax</cite></a>,
+RFC 2396, August 1998, IETF.(See
+<a href="http://www.rfc-editor.org/rfc/rfc2396.txt">http://www.rfc-editor.org/rfc/rfc2396.txt</a>.)
+</dd><dt class="label"><a id="utc"></a>UTC</dt><dd>
+Recommendation TF.460,
+<a href="http://www.itu.int/"><cite>Standard-Frequency and Time-Signal
+Emissions</cite></a>, International
+Telecommunciations Union, Radio Sector (ITU-R).
+</dd><dt class="label"><a id="wcag"></a>WCAG</dt><dd>Ben Caldwell, et al., Eds.,
+<a href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/"><cite>Web
+Content Accessibility Guidelines (WCAG) 2.0</cite></a>, W3C Recommendation, 11 December 2008. (See
+<a href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/">http://www.w3.org/TR/2008/REC-WCAG20-20081211/</a>.)
+</dd><dt class="label"><a id="xlink11"></a>XLink 1.1</dt><dd>Steve DeRose, et al.
+<a href="http://www.w3.org/TR/2010/REC-xlink11-20100506/"><cite>XML Linking Language (XLink) Version 1.1</cite></a>,
+W3C Recommendation, 06 May 2010. (See
+<a href="http://www.w3.org/TR/2010/REC-xlink11-20100506/">http://www.w3.org/TR/2010/REC-xlink11-20100506/</a>.)
+</dd><dt class="label"><a id="xml10"></a>XML 1.0</dt><dd>Tim Bray, et al.
+<a href="http://www.w3.org/TR/2008/REC-xml-20081126/"><cite>Extensible Markup Language (XML)
+1.0 (Fifth Edition)</cite></a>, W3C Recommendation, 26 November 2008. (See
+<a href="http://www.w3.org/TR/2008/REC-xml-20081126/">http://www.w3.org/TR/2008/REC-xml-20081126/</a>.)
+</dd><dt class="label"><a id="xml11"></a>XML 1.1</dt><dd>Tim Bray, et al.
+<a href="http://www.w3.org/TR/2006/REC-xml11-20060816/"><cite>Extensible Markup Language (XML)
+1.1 (Second Edition)</cite></a>, W3C Recommendation, 16 August 2006, edited in place 29 September 2006. (See
+<a href="http://www.w3.org/TR/2006/REC-xml11-20060816/">http://www.w3.org/TR/2006/REC-xml11-20060816/</a>.)
+</dd><dt class="label"><a id="xmlbase"></a>XML Base</dt><dd>Jonathan Marsh and Richard Tobin, Eds.,
+<a href="http://www.w3.org/TR/2009/REC-xmlbase-20090128/"><cite>XML Base (Second Edition)</cite></a>,
+W3C Recommendation, 28 January 2009. (See
+<a href="http://www.w3.org/TR/2009/REC-xmlbase-20090128/">http://www.w3.org/TR/2009/REC-xmlbase-20090128/</a>.)
+</dd><dt class="label"><a id="xmlid"></a>XML ID</dt><dd>Jonathan Marsh, Daniel Veillard, Norman Walsh, Eds.,
+<a href="http://www.w3.org/TR/2005/REC-xml-id-20050909/"><cite>xml:id Version 1.0</cite></a>,
+W3C Recommendation, 09 September 2005. (See
+<a href="http://www.w3.org/TR/2005/REC-xml-id-20050909/">http://www.w3.org/TR/2005/REC-xml-id-20050909/</a>.)
+</dd><dt class="label"><a id="infoset"></a>XML InfoSet</dt><dd>John Cowan and Richard Tobin, Eds.,
+<a href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/"><cite>XML Information Set (Second Edition)</cite></a>,
+W3C Recommendation, 04 February 2004. (See
+<a href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/">http://www.w3.org/TR/2004/REC-xml-infoset-20040204/</a>.)
+</dd><dt class="label"><a id="xml-media"></a>XML Media Types</dt><dd>Makato Murata, Simon St. Laurent,
+Kan Khon, Eds., <a href="http://www.rfc-editor.org/rfc/rfc3023.txt"><cite>XML Media Types</cite></a>,
+RFC 3023, January 2001, IETF.(See
+<a href="http://www.rfc-editor.org/rfc/rfc3023.txt">http://www.rfc-editor.org/rfc/rfc3023.txt</a>.)
+</dd><dt class="label"><a id="xmlns10"></a>XML Namespaces 1.0</dt><dd>Tim Bray, et al.
+<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/"><cite>Namespaces
+in XML 1.0 (Third Edition)</cite></a>, W3C Recommendation, 8 December 2009. (See
+<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">http://www.w3.org/TR/2009/REC-xml-names-20091208/</a>.)
+</dd><dt class="label"><a id="xsd-1"></a>XML Schema Part 1</dt><dd>Henry S. Thompson, David Beech,
+Murray Maloney, Noah Mendelsohn, Eds.,
+<a href="http://www.w3.org/TR/xmlschema-1/"><cite>XML Schema Part 1: Structures</cite></a>,
+W3C Recommendation, 28 October 2004. (See
+<a href="http://www.w3.org/TR/xmlschema-1/">http://www.w3.org/TR/xmlschema-1/</a>.)
+</dd><dt class="label"><a id="xsd-2"></a>XML Schema Part 2</dt><dd>Paul Biron and Ashok Malhotra,
+<a href="http://www.w3.org/TR/xmlschema-2/"><cite>XML Schema Part 2: Datatypes</cite></a>,
+W3C Recommendation, 28 October 2004. (See
+<a href="http://www.w3.org/TR/xmlschema-2/">http://www.w3.org/TR/xmlschema-2/</a>.)
+</dd><dt class="label"><a id="xsl11"></a>XSL 1.1</dt><dd>Anders Berglund,
+<a href="http://www.w3.org/TR/2006/REC-xsl11-20061205/"><cite>Extensible Stylesheet Language (XSL) Version 1.1</cite></a>,
+W3C Recommendation, 05 December 2006. (See
+<a href="http://www.w3.org/TR/2006/REC-xsl11-20061205/">http://www.w3.org/TR/2006/REC-xsl11-20061205/</a>.)
+</dd></dl></div><div class="div1">
+<h2><a id="other-references"></a>K Other References (Non-Normative)</h2><dl><dt class="label"><a id="ccreq"></a>CC-DECODER-REQ</dt><dd><a href="http://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol4/pdf/CFR-2012-title47-vol4-sec79-101.pdf"><cite>Closed Caption Decoder
+Requirements for Analog Television Receivers</cite></a>,
+United States Code of Federal Regulations, Title 47, Volume 1, Part 79, § 79.101. (See
+<a href="http://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol4/pdf/CFR-2012-title47-vol4-sec79-101.pdf">http://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol4/pdf/CFR-2012-title47-vol4-sec79-101.pdf</a>.)
+</dd><dt class="label"><a id="cea608e"></a>CEA-608-E</dt><dd>
+EIA/CEA-608-E,
+<a href="http://www.ce.org/"><cite>Line 21 Data
+Services</cite></a>, EIA/CEA Standard,
+Consumer Electronics Association (CEA).
+</dd><dt class="label"><a id="cea708e"></a>CEA-708-E</dt><dd>
+CEA-708-D,
+<a href="http://www.ce.org/"><cite>Digital Television (DTV) Closed Captioning</cite></a>, CEA Standard,
+Consumer Electronics Association (CEA).
+</dd><dt class="label"><a id="css3-bb"></a>CSS Backgrounds and Borders</dt><dd>Bert Bos, Elika Etamad and Brad Kemper,
+<a href="http://dev.w3.org/csswg/css3-background/"><cite>CSS Backgrounds and Borders Module Level 3</cite></a>, W3C Editor's Draft. (See
+<a href="http://dev.w3.org/csswg/css3-background/">http://dev.w3.org/csswg/css-backgrounds/</a>.)
+</dd><dt class="label"><a id="css3-box"></a>CSS Box Model</dt><dd>Bert Bos, Anton Prowse,
+<a href="http://dev.w3.org/csswg/css-box-3/"><cite>CSS Basic Box Model</cite></a>, W3C Editor's Draft. (See
+<a href="http://dev.w3.org/csswg/css-box-3/">http://dev.w3.org/csswg/css-box-3/</a>.)
+</dd><dt class="label"><a id="css3-fonts"></a>CSS Fonts</dt><dd>John Daggett,
+<a href="http://dev.w3.org/csswg/css-fonts/"><cite>CSS Fonts Module Level 3</cite></a>, W3C Editor's Draft. (See
+<a href="http://dev.w3.org/csswg/css-fonts/">http://dev.w3.org/csswg/css-fonts/</a>.)
+</dd><dt class="label"><a id="css3-frag"></a>CSS Fragmentation</dt><dd>Rossen Atanassov and Elika Etemad,,
+<a href="http://dev.w3.org/csswg/css-break/"><cite>CSS Fragmentation Module Level 3</cite></a>, W3C Editor's Draft. (See
+<a href="http://dev.w3.org/csswg/css-break/">http://dev.w3.org/csswg/css-break/</a>.)
+</dd><dt class="label"><a id="cssruby"></a>CSS Ruby</dt><dd>Elika Etemad and Koji Ishii,
+<a href="http://dev.w3.org/csswg/css-ruby-1/"><cite>CSS Ruby Layout Module Level 1</cite></a>
+W3C Editor's Draft.
+(See <a href="http://dev.w3.org/csswg/css-ruby-1/">http://dev.w3.org/csswg/css-ruby-1/</a>.)
+</dd><dt class="label"><a id="css3-text"></a>CSS Text</dt><dd>Elika Etamad (aka fantasai) and Koji Ishii,
+<a href="http://dev.w3.org/csswg/css-text-3/"><cite>CSS Text Module Level 3</cite></a>, W3C Editor's Draft. (See
+<a href="http://dev.w3.org/csswg/css-text-3/">http://dev.w3.org/csswg/css-text-3/</a>.)
+</dd><dt class="label"><a id="css3-decoration"></a>CSS Text Decoration</dt><dd>Elika Etamad (aka fantasai) and Koji Ishii,
+<a href="http://dev.w3.org/csswg/css-text-decor-3/"><cite>CSS Text Decoration Module Level 3</cite></a>, W3C Editor's Draft. (See
+<a href="http://dev.w3.org/csswg/css-text-decor-3/">http://dev.w3.org/csswg/css-text-decor-3/</a>.)
+</dd><dt class="label"><a id="css3-wm"></a>CSS Writing Modes</dt><dd>Elika Etamad and Koji Ishii,
+<a href="http://dev.w3.org/csswg/css-writing-modes-3/"><cite>CSS Writing Modes Level 3</cite></a>, W3C Editor's Draft. (See
+<a href="http://dev.w3.org/csswg/css-writing-modes-3/">http://dev.w3.org/csswg/css-writing-modes-3/</a>.)
+</dd><dt class="label"><a id="dcmes"></a>DCMES 1.1</dt><dd>Dublin Core Metadata Initiative,
+<a href="http://dublincore.org/documents/dces/"><cite>Dublin Core Metadata Element Set, Version 1.1: Reference Description</cite></a>. (See
+<a href="http://dublincore.org/documents/dces/">http://dublincore.org/documents/dces/</a>.)
+</dd><dt class="label"><a id="jlreq"></a>JLREQ</dt><dd>Richard Ishida et al.,
+<a href="http://www.w3.org/TR/2012/NOTE-jlreq-20120403/"><cite>Requirements for Japanese Text Layout</cite></a>
+W3C Working Group Note, 3 April 2012.
+(See <a href="http://www.w3.org/TR/2012/NOTE-jlreq-20120403/">http://www.w3.org/TR/2012/NOTE-jlreq-20120403/</a>.)
+</dd><dt class="label"><a id="mpeg7-5"></a>MPEG7-5</dt><dd>
+ISO/IEC 15938-5,
+<a href="http://www.iso.org/"><cite>Information technology – Multimedia content description
+interface – Part 5: Multimedia description schemes</cite></a>,
+International Organization for Standardization (ISO).
+</dd><dt class="label"><a id="nsoriginal"></a>NSOriginal</dt><dd>Tim Bray, et al.
+<a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/"><cite>Namespaces
+in XML</cite></a>, W3C Recommendation, 14 January 1999. (See
+<a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/">http://www.w3.org/TR/1999/REC-xml-names-19990114/</a>.)
+</dd><dt class="label"><a id="nsstate"></a>NSState</dt><dd>Norman Walsh, Ed.,
+<a href="http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09.html"><cite>The Disposition
+of Names in an XML Namespace</cite></a>, TAG Finding, 9 January 2006. (See
+<a href="http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09.html">http://www.w3.org/2001/tag/doc/namespaceState-2006-01-09</a>.)
+</dd><dt class="label"><a id="qaf-sg"></a>QAF SG</dt><dd>Karl Dubost, et al.,
+<a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/"><cite>QA
+Framework: Specifications Guidelines</cite></a>, W3C Recommendation, 17
+August 2005. (See
+<a href="http://www.w3.org/TR/qaframe-spec/">http://www.w3.org/TR/qaframe-spec/</a>.)
+</dd><dt class="label"><a id="sdpus"></a>SDP US</dt><dd>Glenn Adams, Monica Martin, Sean Hayes,
+<a href="http://www.w3.org/TR/2013/NOTE-ttml10-sdp-us-20130205/"><cite>TTML Simple Delivery Profile for Closed Captions (US)</cite></a>,
+W3C WG Note, 5 February 2013. (See
+<a href="http://www.w3.org/TR/2013/NOTE-ttml10-sdp-us-20130205/">http://www.w3.org/TR/2013/NOTE-ttml10-sdp-us-20130205/</a>.)
+</dd><dt class="label"><a id="smpte170m"></a>SMPTE 170M</dt><dd>ANSI/SMPTE 170M, 
+<a href="http://www.smpte.org/"><cite>Television – Composite Analog Video
+Signal – NTSC for Studio Applications</cite></a>, SMPTE Standard.
+</dd><dt class="label"><a id="smpte2052"></a>SMPTE 2052-11</dt><dd>SMPTE 2052-11,
+<a href="http://www.smpte.org/"><cite>Conversion from CEA-708 Caption Data to SMPTE-TT</cite></a>,
+SMPTE Recommended Practice.
+</dd><dt class="label"><a id="ttaf1-req"></a>TTAF1-REQ</dt><dd>Glenn Adams, Ed.,
+<a href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/"><cite>Timed Text (TT) Authoring Format 1.0 Use
+Cases and Requirements</cite></a>,
+W3C Working Group Note, 27 April 2006. (See
+<a href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/">http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427/</a>.)
+</dd><dt class="label"><a id="ttml1"></a>TTML1</dt><dd>Glenn Adams, Ed.,
+<a href="http://www.w3.org/TR/2013/REC-ttml1-20130924/"><cite>Timed Text Markup Language 1 (TTML1) (Second Edition)</cite></a>,
+W3C Recommendation, 24 September 2013. (See
+<a href="http://www.w3.org/TR/2013/REC-ttml1-20130924/">http://www.w3.org/TR/2013/REC-ttml1-20130924/</a>.)
+</dd><dt class="label"><a id="xhtml10"></a>XHTML 1.0</dt><dd>Steven Pemberton, et al.,
+<a href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/"><cite>XHTML™ 1.0,
+The Extensible Hypertext Markup Language (Second Edition)</cite></a>,
+W3C Recommendation, 01
+August 2002. (See
+<a href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/">http://www.w3.org/TR/2002/REC-xhtml1-20020801/</a>.)
+</dd></dl></div><div class="div1">
+<h2><a id="requirements"></a>L Requirements (Non-Normative)</h2><p>The Timed Text Markup Language (TTML), also known as the Distribution Format Exchange Profile (DFXP) of the Timed Text Authoring
+Format (TTAF), satisfies a subset of the requirements established by
+<a href="#ttaf1-req">[TTAF1-REQ]</a>. The following table enumerates these requirements and
+indicates the extent to which they are satisfied by this specification, where
+<em>S</em> denotes a requirement is satisfied, <em>P</em> denotes
+a requirement is partially satisfied, and <em>N</em> denotes a
+requirement is not satisfied.</p><a id="requirements-table"></a><table class="common"><caption>Table L-1 – Requirement Satisfaction</caption><col width="10%" span="1"><col width="40%" span="1"><col width="10%" span="1"><col span="1"><tbody><tr><th>ID</th><th>Name</th><th>Status</th><th>Comments</th></tr><tr><td>R100</td><td>Specification Format</td><td>S</td><td></td></tr><tr><td>R101</td><td>Specification Modularity</td><td>S</td><td></td></tr><tr><td>R102</td><td>Specification Organization</td><td>S</td><td></td></tr><tr><td>R103</td><td>Core and Periphery</td><td>S</td><td>TT extension namespaces</td></tr><tr><td>R104</td><td>Evolution of Core</td><td>S</td><td>TT extension namespaces</td></tr><tr><td>R105</td><td>Ownership of Core</td><td>S</td><td>TT namespaces</td></tr><tr><td>R106</td><td>Surjection of Core</td><td>S</td><td></td></tr><tr><td>R107</td><td>Evolution of Periphery</td><td>S</td><td>TT extension namespaces</td></tr><tr><td>R108</td><td>Ownership of Periphery</td><td>S</td><td>Non-TT namespaces</td></tr><tr><td>R109</td><td>Transformation</td><td>S</td><td>Supports 3GPP, QText, RealText, SAMI</td></tr><tr><td>R110</td><td>Streamable Transformation</td><td>S</td><td>Progressive decoding</td></tr><tr><td>R111</td><td>Accessibility – Content</td><td>S</td><td>Alternative document instances</td></tr><tr><td>R112</td><td>Accessibility – Authoring System</td><td>S</td><td></td></tr><tr><td>R200</td><td>Authorability</td><td>S</td><td></td></tr><tr><td>R201</td><td>Multiple Natural Languages</td><td>S</td><td>Alternative document instances</td></tr><tr><td>R202</td><td>Natural Language Coverage</td><td>S</td><td>Unicode 4.0</td></tr><tr><td>R203</td><td>Natural Language Association Granularity</td><td>S</td><td>See <code>xml:lang</code></td></tr><tr><td>R204</td><td>Minimum Character Representability</td><td>S</td><td>Unicode 4.0</td></tr><tr><td>R205</td><td>Intrinsic and Extrinsic Text Content</td><td>P</td><td>Intrinsic only</td></tr><tr><td>R206</td><td>Markup Association</td><td>P</td><td>Intrinsic only</td></tr><tr><td>R207</td><td>Conditional Content</td><td>N</td><td></td></tr><tr><td>R208</td><td>Flowed Text</td><td>S</td><td></td></tr><tr><td>R209</td><td>Logical Flowed Text Vocabulary</td><td>S</td><td></td></tr><tr><td>R210</td><td>Presentational Flowed Text Vocabulary</td><td>S</td><td>Implied mapping from logical flowed text.</td></tr><tr><td>R211</td><td>Flowed Text Vocabulary Relationship</td><td>S</td><td></td></tr><tr><td>R212</td><td>Flowed Text Vocabulary Separation</td><td>N</td><td></td></tr><tr><td>R213</td><td>Non-Flowed Text</td><td>N</td><td></td></tr><tr><td>R214</td><td>Non-Flowed Text Vocabulary</td><td>N</td><td></td></tr><tr><td>R215</td><td>Hybrid Flowed and Non-Flowed Text</td><td>N</td><td></td></tr><tr><td>R216</td><td>Hyperlinking</td><td>N</td><td>Can support via XLink</td></tr><tr><td>R217</td><td>Embedded Graphics</td><td>N</td><td></td></tr><tr><td>R218</td><td>Non-Embedded Graphics</td><td>N</td><td></td></tr><tr><td>R219</td><td>Embedded Fonts</td><td>N</td><td></td></tr><tr><td>R220</td><td>Non-Embedded Fonts</td><td>N</td><td></td></tr><tr><td>R221</td><td>Descriptive Vocabulary</td><td>S</td><td>See <code>ttm:agent</code>, <code>ttm:role</code></td></tr><tr><td>R222</td><td>Embedded Audio</td><td>N</td><td></td></tr><tr><td>R223</td><td>Non-Embedded Audio</td><td>N</td><td></td></tr><tr><td>R290</td><td>Markup Format</td><td>S</td><td></td></tr><tr><td>R291</td><td>Markup Format and Unicode Interaction</td><td>S</td><td></td></tr><tr><td>R292</td><td>Extrinsic Resource References</td><td>N</td><td>No extrinsic references</td></tr><tr><td>R293</td><td>Schema Validity Specification</td><td>S</td><td></td></tr><tr><td>R300</td><td>Inline Styling</td><td>S</td><td></td></tr><tr><td>R301</td><td>Inline Styling Form</td><td>P</td><td>Inline and referential styling</td></tr><tr><td>R301</td><td>Out-of-Line Styling</td><td>N</td><td></td></tr><tr><td>R301</td><td>Out-of-Line Styling Form</td><td>N</td><td></td></tr><tr><td>R304</td><td>Styling Prioritization</td><td>S</td><td></td></tr><tr><td>R305</td><td>Style Parameters – Aural</td><td>N</td><td></td></tr><tr><td>R306</td><td>Style Parameters – Visual</td><td>P</td><td>Supports absolute position, background color, color, display none, display alignment,
+font family, font size, font style, font weight, height, line height, origin,
+opacity, overflow, padding (before, after, start, end), text alignment,
+text shadow (as outline), visibility, width, writing mode, z-index</td></tr><tr><td>R390</td><td>Style Parameter Symmetry</td><td>S</td><td></td></tr><tr><td>R391</td><td>Style Parameter Definitions</td><td>S</td><td></td></tr><tr><td>R392</td><td>Style Parameter Shorthands</td><td>S</td><td></td></tr><tr><td>R401</td><td>Inline Timing</td><td>S</td><td></td></tr><tr><td>R402</td><td>Out-of-Line Timing</td><td>N</td><td></td></tr><tr><td>R403</td><td>Synchronization Parameters</td><td>P</td><td>Supports begin, end, dur</td></tr><tr><td>R404</td><td>Synchronization Parameter Value Spaces</td><td>P</td><td>Supports offset values, media marker values (SMPTE 12M), wall-clock values</td></tr><tr><td>R405</td><td>Time Containment Semantics</td><td>P</td><td>Supports sequential, parallel</td></tr><tr><td>R500</td><td>Animation Modes</td><td>P</td><td>Supports discrete</td></tr><tr><td>R502</td><td>Highlight Animation</td><td>S</td><td><code>&lt;set tts:backgroundColor="..."/&gt;</code></td></tr><tr><td>R503</td><td>Fade Transition Animation</td><td>S</td><td><code>&lt;set tts:opacity="..."/&gt;</code></td></tr><tr><td>R504</td><td>Animated Style Parameters – Aural</td><td>N</td><td></td></tr><tr><td>R505</td><td>Animated Style Parameters – Visual</td><td>P</td><td>Supports animating background color, color, display, opacity, origin, visibility</td></tr><tr><td>N506</td><td>Animated Content</td><td>S</td><td></td></tr><tr><td>R600</td><td>Metadata Item Association</td><td>S</td><td>See <code>metadata</code>, <a href="#element-vocab-group-metadata"><code>Metadata.class</code></a></td></tr><tr><td>R601</td><td>Metadata Item Constituents</td><td>P</td><td>Supports name, value</td></tr><tr><td>R602</td><td>Metadata Item Value Representation</td><td>P</td><td>See <code>metadata</code></td></tr><tr><td>R603</td><td>Metadata Item Extensibility</td><td>S</td><td>See <code>metadata</code></td></tr><tr><td>R604</td><td>Metadata Item Validation</td><td>S</td><td>See <code>metadata</code></td></tr><tr><td>R690</td><td>Dublin Core Preference</td><td>N</td><td>Uses <code>ttm:copyright</code>, <code>ttm:desc</code>, <code>ttm:title</code></td></tr></tbody></table></div><div class="div1">
+<h2><a id="derivation"></a>M Vocabulary Derivation (Non-Normative)</h2><p>This appendix provides information about the derivation of TTML
+vocabulary, separately describing derivation of elements and
+attributes.</p><table border="1" class="ednote" summary="Editorial note: Update Derivation"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: Update Derivation</b></td><td align="right" valign="top">2015-01-14</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Update derivation tables to include new vocabulary added in TTML2.</td></tr></table><div class="div2">
+<h3><a id="d3e37582"></a>M.1 Element Derivation</h3><p>The first column of <a href="#element-vocab-derivation-table"><b>Table M-1 – Elements</b></a>
+specifies a TTML element vocabulary item; the second column specifies the
+syntactic and/or semantic model on which the vocabulary item is based;
+the third column specifies the reference that defines
+the model (if a model is indicated);
+the fourth column specifies details about the derivation; the last
+column refers to additional notes describing the nature of the
+derivation.</p><p>In the fourth column, which describes details of derivation, a
+notation is use to indicate the addition or removal of an attribute.
+For example, in the derivation of the <code>tt:div</code> element, the
+details column includes "-@class", which denotes that the
+<code>class</code> attribute that is specified for use with the
+<code>xhtml:div</code> model element is not specified for use with the
+corresponding TTML element; in contrast, the details column includes
+"+@begin", which denotes that a <code>begin</code> attribute is added
+that is not specified for use with the <code>xhtml:div</code> model
+element.</p><a id="element-vocab-derivation-table"></a><table class="common"><caption>Table M-1 – Elements</caption><col width="20%" span="1"><col width="17%" span="1"><col width="13%" align="center" span="1"><col width="40%" span="1"><col width="10%" align="center" span="1"><tbody><tr><td><span class="strong">Element</span></td><td><span class="strong">Model</span></td><td><span class="strong">Reference</span></td><td><span class="strong">Details</span></td><td><span class="strong">Notes</span></td></tr><tr><td><a href="#animation-vocabulary-animate"><code>tt:animate</code></a></td><td><code>svg:animate</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@* except begin, dur, end; +@tts:*, +@xml:lang, +@xml:space</td><td>3,6</td></tr><tr><td><a href="#animation-vocabulary-animation"><code>tt:animation</code></a></td><td><code>tt:layout</code></td><td><a href="#ttml1">[TTML1]</a></td><td>conceptual derivation</td><td>12</td></tr><tr><td><a href="#document-structure-vocabulary-body"><code>tt:body</code></a></td><td><code>xhtml:body</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
++@timeContainer, +@ttm:*, +@tts:*; content model
+subsetted to zero or more division (div) children, and supersetted by
+optional metadata and animation children</td><td>1,2</td></tr><tr><td><a href="#content-vocabulary-br"><code>tt:br</code></a></td><td><code>xhtml:br</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@title; +@ttm:*, +@tts:*, +@xml:lang, +@xml:space;
+content model supersetted by
+optional metadata and animation children for congruity with other
+content vocabulary</td><td>1,2</td></tr><tr><td><a href="#content-vocabulary-div"><code>tt:div</code></a></td><td><code>xhtml:div</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
++@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
+subsetted to zero or more paragraph (p) children, and supersetted by
+optional metadata and animation children</td><td>1,2,3</td></tr><tr><td><a href="#document-structure-vocabulary-head"><code>tt:head</code></a></td><td><code>xhtml:head</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@dir, -@lang, -@profile; +@id, +@xml:space; content model changed to
+optional metadata children, followed by optional styling child,
+followed by optional layout child</td><td>1,3</td></tr><tr><td><a href="#layout-vocabulary-layout"><code>tt:layout</code></a></td><td><code>fo:simple-page-master</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-metadata"><code>tt:metadata</code></a></td><td><code>svg:metadata</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@xml:base; +@ttm:*, +@xml:lang, +@xml:space; content model
+subsetted to foreign namespace element content only (no #PCDATA)</td><td>3,5</td></tr><tr><td><a href="#content-vocabulary-p"><code>tt:p</code></a></td><td><code>xhtml:p</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
++@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
+subsetted to zero or more span children, and supersetted by optional
+metadata and animation children</td><td>1,2,3</td></tr><tr><td><a href="#layout-vocabulary-region"><code>tt:region</code></a></td><td><code>fo:region-*</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#animation-vocabulary-set"><code>tt:set</code></a></td><td><code>svg:set</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@* except begin, dur, end; +@tts:*, +@xml:lang, +@xml:space</td><td>3,6</td></tr><tr><td><a href="#content-vocabulary-span"><code>tt:span</code></a></td><td><code>xhtml:span</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@class, -@dir, -@lang, -@on*, -@title; +@begin, +@dur, +@end, +@region,
++@timeContainer, +@ttm:*, +@tts:*, +@xml:space; content model
+subsetted to zero or more #PCDATA or break (br) children, and
+supersetted by optional metadata and animation children</td><td>1,2,3</td></tr><tr><td><a href="#styling-vocabulary-style"><code>tt:style</code></a></td><td><em>style specification</em></td><td><a href="#css2">[CSS2]</a></td><td>XML representation of identified set of pairs of style property
+name and value, with optional inclusion of other styles by reference
+to other style elements</td><td>7</td></tr><tr><td><a href="#styling-vocabulary-styling"><code>tt:styling</code></a></td><td><code>xhtml:style</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>XML representation of a set of style specifications sets, each
+represented by a style child element</td><td>1,7</td></tr><tr><td><a href="#document-structure-vocabulary-tt"><code>tt:tt</code></a></td><td><code>xhtml:html</code></td><td><a href="#xhtml10">[XHTML 1.0]</a></td><td>-@dir, -@lang; +@id, +@ttp:*, +@xml:space; content model subsetted by
+permitting body and/or head to be optional</td><td>1,8</td></tr><tr><td><a href="#metadata-vocabulary-actor"><code>ttm:actor</code></a></td><td><code>mpeg7:Creator</code></td><td><a href="#mpeg7-5">[MPEG7-5]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-agent"><code>ttm:agent</code></a></td><td><code>mpeg7:Agent</code></td><td><a href="#mpeg7-5">[MPEG7-5]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-copyright"><code>ttm:copyright</code></a></td><td><code>mpeg7:CopyrightString</code></td><td><a href="#mpeg7-5">[MPEG7-5]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-desc"><code>ttm:desc</code></a></td><td><code>svg:desc</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@class, -@style, -@xml:base</td><td>2,5,9</td></tr><tr><td><a href="#metadata-vocabulary-name"><code>ttm:name</code></a></td><td><code>mpeg7:Name</code></td><td><a href="#mpeg7-5">[MPEG7-5]</a></td><td>conceptual derivation</td><td>4</td></tr><tr><td><a href="#metadata-vocabulary-title"><code>ttm:title</code></a></td><td><code>svg:title</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>-@class, -@style, -@xml:base</td><td>2,5,9</td></tr><tr><td><a href="#profile-vocabulary-extension"><code>ttp:extension</code></a></td><td><code>@requiredExtensions</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>10</td></tr><tr><td><a href="#profile-vocabulary-extensions"><code>ttp:extensions</code></a></td><td><code>@requiredExtensions</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>10</td></tr><tr><td><a href="#profile-vocabulary-feature"><code>ttp:feature</code></a></td><td><code>@requiredFeatures</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>10</td></tr><tr><td><a href="#profile-vocabulary-features"><code>ttp:features</code></a></td><td><code>@requiredFeatures</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>10</td></tr><tr><td><a href="#profile-vocabulary-profile"><code>ttp:profile</code></a></td><td><code>@baseProfile</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>conceptual derivation</td><td>11</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><ol class="enumar"><li><p>Derivation is indicated with respect to the strict DTD defined
+by <a href="#xhtml10">[XHTML 1.0]</a>, §A.1.</p></li><li><p>The <code>class</code> attribute is effectively replaced by the
+<code>style</code>
+attribute, which, instead of specifying an inline style,
+refers indirectly to one or more <a href="#styling-vocabulary-style"><code>style</code></a>
+elements that define a set of style specification sets.</p></li><li><p>The <code>xml:lang</code> and <code>xml:space</code> attributes are defined for all element
+types in order to support their inheritance semantics to operate in
+the context of foreign namespace elements.</p></li><li><p>Derivation is conceptual (notional) only.</p></li><li><p>The <code>xml:base</code> attribute is not used since there are no external
+references from core vocabulary.</p></li><li><p>The <code>attributeName</code> and <code>to</code> attributes of
+<code>svg:set</code> are replaced by the
+direct expression of the target attribute name and value by use of a
+<code>tts:*</code> attribute.</p></li><li><p>CSS style specification syntax is mapped to XML by use of
+attributes defined in the TT Style Namespace.</p></li><li><p>The <code>xml:id</code> attribute is defined for use on all element types.</p></li><li><p>The <code>style</code> attribute is supported only on
+<a href="#terms-content-element">content element</a>.</p></li><li><p>Derived from the use of <code>@requiredExtensions</code>
+and <code>@requiredFeatures</code> on the <code>svg:svg</code> element,
+but extended to support distinct specification of optionality.</p></li><li><p>Derived from the use of <code>@baseProfile</code>
+and <code>@version</code> on the <code>svg:svg</code> element.</p></li><li><p>Conceptually derived from existing <code>tt:layout</code> element,
+which is a generic container for layout specifications, but for use
+in defining animation specifications that apply to targeted elements.</p></li></ol></div></div><div class="div2">
+<h3><a id="d3e38099"></a>M.2 Attribute Derivation</h3><p>The first column of <a href="#attribute-vocab-derivation-table"><b>Table M-2 – Attributes</b></a>
+specifies a TTML attribute vocabulary item; the second column specifies the
+syntactic and/or semantic model on which the vocabulary item is based;
+the third column specifies the reference that defines
+the model (if a model is indicated);
+the fourth column specifies details about the derivation; the last
+column refers to additional notes describing the nature of the
+derivation.</p><p>In the fourth column, which describes details of derivation, a
+notation is use to indicate the addition or removal of an attribute
+value.  For example, in the derivation of the <code>timeContainer</code>
+attribute,
+the details column includes "-excl", which denotes that the
+<code>excl</code> value that is specified for use with the
+<code>timeContainer</code> model attribute is not specified for use with the
+corresponding TTML attribute; similarly, an "+<em>value</em>"
+in the details column indicates that the attribute's values have been
+extended to include <em>value</em>.</p><p>Only those attributes that are specified for use on more than one TTML
+element type are listed below. Those per-element namespace attributes
+that are uniquely defined for a specific TTML element type are not
+listed below, but are considered to be part of the specific element
+type's derivation described in <a href="#element-vocab-derivation-table"><b>Table M-1 – Elements</b></a>
+above.</p><a id="attribute-vocab-derivation-table"></a><table class="common"><caption>Table M-2 – Attributes</caption><col width="20%" span="1"><col width="17%" span="1"><col width="13%" align="center" span="1"><col width="40%" span="1"><col width="10%" align="center" span="1"><tbody><tr><td><span class="strong">Attribute</span></td><td><span class="strong">Model</span></td><td><span class="strong">Reference</span></td><td><span class="strong">Details</span></td><td><span class="strong">Notes</span></td></tr><tr><td><a href="#timing-attribute-begin"><code>begin</code></a></td><td><code>begin</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>see notes</td><td>2,3,4</td></tr><tr><td><a href="#timing-attribute-dur"><code>dur</code></a></td><td><code>dur</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>see notes</td><td>2,3,4</td></tr><tr><td><a href="#timing-attribute-end"><code>end</code></a></td><td><code>end</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>see notes</td><td>2,3,4</td></tr><tr><td><a href="#layout-attribute-region"><code>region</code></a></td><td><code>master-reference</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>conceptual derivation</td><td></td></tr><tr><td><a href="#style-attribute-style"><code>style</code></a></td><td><code>class</code></td><td><a href="#css2">[CSS2]</a></td><td>dereferences style specification(s) directly</td><td></td></tr><tr><td><a href="#timing-attribute-timeContainer"><code>timeContainer</code></a></td><td><code>timeContainer</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>
+-<code>excl</code>,
+-<code>none</code>;
+no default attribute value
+</td><td>5</td></tr><tr><td><a href="#metadata-attribute-agent"><code>ttm:agent</code></a></td><td><em>none</em></td><td></td><td>used to attribute agent of content</td><td></td></tr><tr><td><a href="#metadata-attribute-role"><code>ttm:role</code></a></td><td><em>none</em></td><td></td><td>used to attribute role of content</td><td></td></tr><tr><td><a href="#parameter-attribute-cellResolution"><code>ttp:cellResolution</code></a></td><td><em>none</em></td><td></td><td>expresses uniform grid resolution for cell based coordinates</td><td></td></tr><tr><td><a href="#parameter-attribute-clockMode"><code>ttp:clockMode</code></a></td><td><em>none</em></td><td></td><td>determines how to interpret time expressions</td><td></td></tr><tr><td><a href="#parameter-attribute-frameRate"><code>ttp:frameRate</code></a></td><td><em>none</em></td><td></td><td>expresses integral frame rate</td><td></td></tr><tr><td><a href="#parameter-attribute-frameRateMultiplier"><code>ttp:frameRateMultiplier</code></a></td><td><em>none</em></td><td></td><td>used to express non-integral, rational frame rates</td><td></td></tr><tr><td><a href="#parameter-attribute-markerMode"><code>ttp:markerMode</code></a></td><td><em>none</em></td><td></td><td>expresses marker continuity semantics</td><td></td></tr><tr><td><a href="#parameter-attribute-pixelAspectRatio"><code>ttp:pixelAspectRatio</code></a></td><td><em>none</em></td><td></td><td>expresses pixel aspect ratio of related media</td><td></td></tr><tr><td><a href="#profile-attribute-profile"><code>ttp:profile</code></a></td><td><em>none</em></td><td></td><td>expresses profile of TTML used by a <a href="#terms-document-instance">document instance</a></td><td></td></tr><tr><td><a href="#parameter-attribute-dropMode"><code>ttp:dropMode</code></a></td><td><em>none</em></td><td></td><td>expresses frame counting (drop) modes</td><td></td></tr><tr><td><a href="#parameter-attribute-subFrameRate"><code>ttp:subFrameRate</code></a></td><td><em>none</em></td><td></td><td>expresses sub-frame rate</td><td></td></tr><tr><td><a href="#parameter-attribute-tickRate"><code>ttp:tickRate</code></a></td><td><em>none</em></td><td></td><td>used to interpret tick based time expressions</td><td></td></tr><tr><td><a href="#parameter-attribute-timeBase"><code>ttp:timeBase</code></a></td><td><em>none</em></td><td></td><td>used to interpret semantics of time expressions</td><td></td></tr><tr><td><a href="#parameter-attribute-version"><code>ttp:version</code></a></td><td><code>version</code></td><td><a href="#svg11">[SVG 1.1]</a></td><td>used only integer values</td><td></td></tr><tr><td><a href="#style-attribute-backgroundColor"><code>tts:backgroundColor</code></a></td><td><code>background-color</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1,6</td></tr><tr><td><a href="#style-attribute-border"><code>tts:border</code></a></td><td><code>border</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1,6</td></tr><tr><td><a href="#style-attribute-color"><code>tts:color</code></a></td><td><code>color</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>6</td></tr><tr><td><a href="#style-attribute-direction"><code>tts:direction</code></a></td><td><code>direction</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td></td></tr><tr><td><a href="#style-attribute-display"><code>tts:display</code></a></td><td><code>display</code></td><td><a href="#css2">[CSS2]</a></td><td>only <code>auto</code>, <code>none</code></td><td></td></tr><tr><td><a href="#style-attribute-displayAlign"><code>tts:displayAlign</code></a></td><td><code>display-align</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#style-attribute-extent"><code>tts:extent</code></a></td><td><code>width</code>, <code>height</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>shorthand property</td><td></td></tr><tr><td><a href="#style-attribute-fontFamily"><code>tts:fontFamily</code></a></td><td><code>font-family</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, extends generic family names</td><td>1</td></tr><tr><td><a href="#style-attribute-fontSize"><code>tts:fontSize</code></a></td><td><code>font-size</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1,7</td></tr><tr><td><a href="#style-attribute-fontStyle"><code>tts:fontStyle</code></a></td><td><code>font-style</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>backslant</code></td><td>1</td></tr><tr><td><a href="#style-attribute-fontWeight"><code>tts:fontWeight</code></a></td><td><code>font-weight</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>bolder</code>, -<code>lighter</code>, -<code>&lt;number&gt;</code></td><td>1</td></tr><tr><td><a href="#style-attribute-lineHeight"><code>tts:lineHeight</code></a></td><td><code>line-height</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>&lt;number&gt;</code>, -<code>&lt;space&gt;</code></td><td>1</td></tr><tr><td><a href="#style-attribute-opacity"><code>tts:opacity</code></a></td><td><code>opacity</code></td><td><a href="#css3-color">[CSS3 Color]</a></td><td>-<code>inherit</code></td><td></td></tr><tr><td><a href="#style-attribute-origin"><code>tts:origin</code></a></td><td><code>top</code>, <code>left</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>shorthand property</td><td></td></tr><tr><td><a href="#style-attribute-overflow"><code>tts:overflow</code></a></td><td><code>overflow</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>auto</code>, -<code>error-if-overflow</code></td><td></td></tr><tr><td><a href="#style-attribute-padding"><code>tts:padding</code></a></td><td><code>padding</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>8</td></tr><tr><td><a href="#style-attribute-showBackground"><code>tts:showBackground</code></a></td><td><code>showBackground</code></td><td><a href="#smil3">[SMIL 3.0]</a></td><td>-<code>inherit</code></td><td></td></tr><tr><td><a href="#style-attribute-textAlign"><code>tts:textAlign</code></a></td><td><code>text-align</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#style-attribute-textDecoration"><code>tts:textDecoration</code></a></td><td><code>text-decoration</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1,9,12</td></tr><tr><td><a href="#style-attribute-textOrientation"><code>tts:textOrientation</code></a></td><td><code>text-orientation</code></td><td><a href="#css3-wm">[CSS Writing Modes]</a></td><td>
+-<code>inherit</code>,
+-<code>sideways-left</code>,
+-<code>sideways-right</code>,
+-<code>use-glyph-orientation</code>
+</td><td>1</td></tr><tr><td><a href="#style-attribute-textOutline"><code>tts:textOutline</code></a></td><td><code>text-shadow</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>10,12</td></tr><tr><td><a href="#style-attribute-unicodeBidi"><code>tts:unicodeBidi</code></a></td><td><code>unicode-bidi</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#style-attribute-visibility"><code>tts:visibility</code></a></td><td><code>visibility</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code>, -<code>collapse</code></td><td></td></tr><tr><td><a href="#style-attribute-wrapOption"><code>tts:wrapOption</code></a></td><td><code>wrap-option</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#style-attribute-writingMode"><code>tts:writingMode</code></a></td><td><code>writing-mode</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>
+-<code>inherit</code>,
+-<code>bt-lr</code>,
+-<code>bt-rl</code>,
+-<code>lr-bt</code>,
+-<code>rl-bt</code>,
+-<code>lr-alternating-rl-bt</code>,
+-<code>lr-alternating-rl-tb</code>,
+-<code>lr-inverting-rl-bt</code>,
+-<code>lr-inverting-rl-tb</code>,
+-<code>tb-lr-in-lr-pairs</code>
+</td><td>1</td></tr><tr><td><a href="#style-attribute-zIndex"><code>tts:zIndex</code></a></td><td><code>z-index</code></td><td><a href="#xsl11">[XSL 1.1]</a></td><td>-<code>inherit</code></td><td>1</td></tr><tr><td><a href="#content-attribute-xml-id"><code>xml:id</code></a></td><td><code>xml:id</code></td><td><a href="#xmlid">[XML ID]</a></td><td>complies with model</td><td></td></tr><tr><td><a href="#content-attribute-xml-lang"><code>xml:lang</code></a></td><td><code>xml:lang</code></td><td><a href="#xml10">[XML 1.0]</a></td><td>complies with model</td><td></td></tr><tr><td><a href="#content-attribute-xml-space"><code>xml:space</code></a></td><td><code>xml:space</code></td><td><a href="#xml10">[XML 1.0]</a></td><td>see notes</td><td>11</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><ol class="enumar"><li><p>Attribute name and/or value(s) are normalized to use
+<em>lowerCamelCase</em> naming convention.</p></li><li><p>Restricted to expressing a clock value that denotes one of the
+following in accordance to whether the parameter expressed by the
+<code>ttp:timeBase</code> attribute is <code>media</code>, <code>smpte</code>,
+or <code>clock</code>, respectively:
+(1) an offset from an implicit syncbase that is linked to a media time
+line, (2) an event time
+that represents the occurrence of an implicit media marker, or (3) a wall-clock
+time.</p></li><li><p>Syntactically subsets and supersets the <a href="#smil3">[SMIL 3.0]</a>&nbsp;<code>Clock-value</code> syntax as follows:
+(1) requires non-negative <code>Full-clock-value</code> or
+<code>Timecount-value</code>;
+(2) if <code>Full-clock-value</code>
+then <em>hours</em> must be two or more digits;
+(3) if <code>Timecount-value</code>, then <em>metric</em> must be
+specified;
+(4) uses <code>m</code> as alias for <code>min</code> metric to denote
+minutes;
+(5) adds <code>f</code> and <code>t</code> metrics denoting frames and
+ticks, respectively;
+(6) adds alternative expression of optional <code>Fraction</code> in
+<code>Full-clock-value</code> by specifying frame count or frame
+count with subframe count.
+</p></li><li><p>
+Interpretation of time expression is further constrained by
+parameters expressed by
+<code>ttp:clockMode</code>,
+<code>ttp:dropMode</code>,
+<code>ttp:frameRate</code>,
+<code>ttp:frameRateMultiplier</code>,
+<code>ttp:markerMode</code>,
+<code>ttp:subFrameRate</code>,
+<code>ttp:tickRate</code>, and
+<code>ttp:timeBase</code> attributes.</p></li><li><p>Uses subset of named colors from model to which two aliases are
+added as follows: <code>magenta</code> as <code>fuchsia</code>, and <code>cyan</code>
+as <code>aqua</code>.</p></li><li><p>If not specified, then parallel (par) container semantics apply to
+the element types specified by <a href="#timing-attribute-timeContainer"><b>12.2.4 timeContainer</b></a>.</p></li><li><p>Restricts size to length specification which can be a percentage;
+adds optional second length (or percentage) for
+specifying separate horizontal and vertical scaling of glyph's EM
+square.</p></li><li><p>Expressed in terms of writing mode relative padding properties
+rather than absolute padding properties.</p></li><li><p>Excludes <code>blink</code> and <code>no-blink</code> values.</p></li><li><p>Uses only one length specification instead of two, where one length
+defines distance of outline effect from nominal edge of glyph contour
+outline perpendicular to point of glyph contour. Percentage lengths
+are also added to express outline effect in relative to font size.
+Outline effects are intended to be drawn both outside of outer closed
+contours and inside of inner closed contours.</p></li><li><p>On root element, default attribute value specified as
+<code>default</code>, which is defined in terms of whitespace
+normalization. Semantics of preservation and default normalization are
+defined in terms of presentation semantics by <a href="#content-attribute-xml-space"><b>8.2.9 xml:space</b></a>.</p></li><li><p>Defined to be inheritable.</p></li></ol></div></div></div><div class="div1">
+<h2><a id="qa"></a>N QA Framework Compliance (Non-Normative)</h2><p>This appendix specifies the compliance of this specification with the
+requirements and guidelines defined by <a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/">QA
+Framework Specifications Guidelines</a>&nbsp;<a href="#qaf-sg">[QAF SG]</a>.</p><div class="div2">
+<h3><a id="d3e39092"></a>N.1 Requirements</h3><a id="qa-framework-requirements-table"></a><table class="common"><caption>Table N-1 – QA Framework Requirements Checklist</caption><col width="76%" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><tbody><tr><td><span class="strong">Requirement</span></td><td><span class="strong">YES</span></td><td><span class="strong">NO</span></td><td><span class="strong">N/A</span></td><td><span class="strong">Notes</span></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#include-conformance-clause-principle">Requirement 01: Include a conformance
+clause</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-scope-principle">Requirement 02: Define the scope.</a></td><td><a href="#intro">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#implement-principle">Requirement 03: Identify who or what will implement the specification.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ref-norm-principle">Requirement 04: Make a list of normative references.</a></td><td><a href="#references">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-terms-principle">Requirement 05: Define the terms used in the normative parts of the specification.</a></td><td><a href="#definitions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conf-label-principle">Requirement 06: Create conformance labels for each part of the conformance model.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#consistent-style-principle">Requirement 07: Use a consistent style for conformance requirements and explain how to distinguish them.</a></td><td><a href="#conventions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#req-opt-conf-principle">Requirement 08: Indicate which conformance requirements are mandatory, which are recommended, and which are optional.</a></td><td><a href="#conventions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdivide-mandatory-principle">Requirement 09: If the technology is subdivided, then indicate which subdivisions are mandatory for conformance.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdiv-constraints-principle">Requirement 10: If the technology is subdivided, then address subdivision constraints.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#likehood-extension-principle">Requirement 11: Address Extensibility.</a></td><td><a href="#doctypes">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#deprecated-feature-principle">Requirement 12: Identify deprecated features.</a></td><td></td><td></td><td>N/A</td><td>1</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#degree-support-principle">Requirement 13: Define how each class of product handles each deprecated feature.</a></td><td></td><td></td><td>N/A</td><td>1</td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><ol class="enumar"><li><p>No feature is deprecated by this version of this specification.</p></li></ol></div></div><div class="div2">
+<h3><a id="d3e39256"></a>N.2 Guidelines</h3><a id="qa-framework-guidelines-table"></a><table class="common"><caption>Table N-2 – QA Framework Guidelines Checklist</caption><col width="76%" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><col width="6%" align="center" span="1"><tbody><tr><td><span class="strong">Guideline</span></td><td><span class="strong">YES</span></td><td><span class="strong">NO</span></td><td><span class="strong">N/A</span></td><td><span class="strong">Notes</span></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conformance-model-gp">Good Practice 01: Define the specification's conformance model in the conformance clause.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#norm-informative-gp">Good Practice 02: Specify in the conformance clause how to distinguish normative from informative content.</a></td><td><a href="#conventions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#conformance-claim-gp">Good Practice 03: Provide the wording for conformance claims.</a></td><td><a href="#claims">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ics-gp">Good Practice 04: Provide an Implementation Conformance Statement Pro Forma.</a></td><td></td><td>NO</td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ics-claim-gp">Good Practice 05: Require an Implementation Conformance Statement as part of valid conformance claims.</a></td><td><a href="#claims">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#use-example-gp">Good Practice 06: Provide examples, use cases, and graphics.</a></td><td><a href="#example">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#write-sample-gp">Good Practice 07: Write sample code or tests.</a></td><td>YES</td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#ref-define-practice">Good Practice 08: When imposing requirements by normative references, address conformance dependencies.</a></td><td><a href="#references">YES</a></td><td></td><td></td><td>1</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-terms-inline-gp">Good Practice 09: Define unfamiliar terms in-line and consolidate the definitions in a glossary section.</a></td><td><a href="#definitions">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#reuse-terms-gp">Good Practice 10: Use terms already defined without changing their definition.</a></td><td><a href="#definitions">YES</a></td><td></td><td></td><td>2</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#formal-language-gp">Good Practice 11: Use formal languages when possible.</a></td><td><a href="#schemas">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#write-assertion-gp">Good Practice 12: Write Test Assertions.</a></td><td></td><td>NO</td><td></td><td>3</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#subdivide-foster-gp">Good Practice 13: Create subdivisions of the technology when warranted.</a></td><td><a href="#conformance">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#rules-profiles-gp">Good Practice 14: If the technology is profiled, define rules for creating new profiles.</a></td><td><a href="#vocabulary-profiling">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#need-option-gp">Good Practice 15:Use optional features as warranted.</a></td><td>YES</td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#label-options-gp">Good Practice 16: Clearly identify optional features.</a></td><td>YES</td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#constraints-gp">Good Practice 17: Indicate any limitations or constraints on optional features.</a></td><td>YES</td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#extensions-prohibited-gp">Good Practice 18: If extensibility is allowed, define an extension mechanism.</a></td><td><a href="#extension-vocabulary-overview">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#breaking-conformance-gp">Good Practice 19: Warn extension creators to create extensions that do not interfere with conformance.</a></td><td><a href="#extension-vocabulary-overview">YES</a></td><td></td><td></td><td></td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#define-error-gp">Good Practice 20: Define error-handling for unknown extensions.</a></td><td><a href="#conformance-processor">YES</a></td><td></td><td></td><td>4</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#workaround-gp">Good Practice 21: Explain how to avoid using a deprecated feature.</a></td><td></td><td></td><td>N/A</td><td>5</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#obsolete-gp">Good Practice 22: Identify obsolete features.</a></td><td></td><td></td><td>N/A</td><td>5</td></tr><tr><td><a href="http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#error-handling-gp">Good Practice 23: Define an error handling mechanism.</a></td><td><a href="#reduced-infoset">YES</a></td><td></td><td></td><td></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><ol class="enumar"><li><p>When making normative references to external specifications,
+specific clauses or sections are cited.</p></li><li><p>See also <a href="#derivation"><b>M Vocabulary Derivation</b></a>.</p></li><li><p>Test assertions and test suites will be provided prior to entering
+Proposed Recommendation (PR) phase.</p></li><li><p>See criterion #3 in <a href="#conformance-processor"><b>3.2 Processor Conformance</b></a> and definition of
+TTML <a href="#doctypes">Abstract Document Instance</a>.</p></li><li><p>No feature is deprecated or obsoleted by this version of this specification.</p></li></ol></div></div></div><div class="div1">
+<h2><a id="streaming"></a>O Streaming TTML Content (Non-Normative)</h2><p>TTML Content is designed to support streamability by implementing the
+following properties:</p><ul><li><p>can be progressively encoded (i.e., does not require computing
+subsequent data prior to sending current data);</p></li><li><p>can be progressively decoded (i.e., does not require forward
+references, but uses only reverse references when necessary);</p></li><li><p>does not require dereferencing (and subsequent loading) of any
+resources other than TTML Content (i.e., no embedded URIs);</p></li><li><p>does not support alternative content forms (e.g., different
+language, graphics formats, time bases) in a single document;</p></li><li><p>has timing structure compiled into inline format that makes
+possible a temporal ordering of content that follows temporal
+presentation order;</p></li><li><p>constrains content models to prevent arbitrary nested content
+structures;</p></li></ul><p>One possible means by which TTML Content may be streamed is to
+partition a <a href="#terms-document-instance">document instance</a>'s information set into
+non-overlapping fragments, where one particular fragment, call it the
+<em>root fragment</em>, represents the front matter (head) of the
+<a href="#terms-document-instance">document instance</a> as well as its top level structural elements, and
+other fragments represent content whose time intervals are expected to
+be active in parallel.</p><p>In applications that require arbitrary (random) entry into a
+stream, i.e., the property of being able to start reading data at an
+arbitrary data access unit, the root fragment will be repetitively
+transmitted (inserted) into the stream in order to permit a decoder to
+resynchronize and acquire sufficient structural information in the
+information set in order to interpret subsequent content
+fragments.</p><p>An example of such a fragmentation of a <a href="#terms-document-instance">document instance</a> is
+shown in <a href="#fragment-streaming-graphic"><b>Figure 3 – Fragment Streaming</b></a>.</p><a id="fragment-streaming-graphic"></a><table class="example-images"><caption>Figure 3 – Fragment Streaming</caption><col span="1"><tbody><tr><td><img src="images/streaming.png" alt="Fragment Streaming"></td></tr></tbody></table><div class="note"><p class="prefix"><b>Note:</b></p><p>This specification does not define a transport buffer model or a decoder
+capabilities model.</p></div></div><div class="div1">
+<h2><a id="common-styling"></a>P Common Caption Style Examples (Non-Normative)</h2><p>This section provides examples of the following common caption styles using TTML Content
+to obtain the desired behavior:</p><ul><li><p>Pop-On Captions</p></li><li><p>Roll-Up Captions</p></li><li><p>Paint-On Captions</p></li></ul><div class="div2">
+<h3><a id="pop-on-example"></a>P.1 Pop-On Caption Example</h3><p>An example of paint-on captions. In this example, two regions are targeted with alternating, paint-on content, where content is timed
+using explicit sequential time containment rules. Each paragraph is non-overlapping in time and appears in the same single row
+of its targeted region.</p><a id="pop-on-example-1-s"></a><table class="example"><caption>Example – Pop-On Captions</caption><tbody><tr><td>
+<div class="exampleInner"><pre>&lt;tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;head&gt;
+    &lt;layout&gt;
+      &lt;region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 1c"/&gt;
+      &lt;region xml:id="r2" tts:color="yellow" tts:origin="10c 8c" tts:extent="40c 1c"/&gt;
+    &lt;/layout&gt;
+  &lt;/head&gt;
+  &lt;body&gt;
+    &lt;div timeContainer="seq"&gt;
+      &lt;p region="r1" dur="4s"&gt;Lorem ipsum dolor sit&lt;/p
+      &lt;p region="r2" dur="4s"&gt;Amet consectetur adipiscing elit&lt;/p&gt;
+      &lt;p region="r1" dur="6s"&gt;Sed do eiusmod tempor incididunt labore&lt;/p&gt;
+      &lt;p region="r2" dur="4s"&gt;et dolore magna aliqua&lt;/p&gt;
+      &lt;p region="r1" dur="7s"&gt;Ut enim ad minim veniam quis, nostrud&lt;/p&gt;
+    &lt;/div&gt;
+  &lt;/body&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table></div><div class="div2">
+<h3><a id="roll-up-example"></a>P.2 Roll-Up Caption Example</h3><p>An example of roll-up captions. Roll-up effects are achieved by using overlapped time intervals, where zero, one, or two paragraphs appear in the region
+at a given time. Each paragraph consumes a single row (line) of the region since no wrapping occurs. Depending on whether a <a href="#terms-presentation-processor">presentation processor</a> supports
+<a href="#semantics-smooth-scrolling-recommendation">smooth scrolling between adjacent synchronic intermediate document instances</a>, the transitions, i.e., moving an
+old paragraph (line) out and a new paragraph (line) in, will be either smooth or discrete.</p><a id="roll-up-example-1-s"></a><table class="example"><caption>Example – Roll-Up Captions</caption><tbody><tr><td>
+<div class="exampleInner"><pre>&lt;tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;head&gt;
+    &lt;layout&gt;
+      &lt;region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 2c"/&gt;
+    &lt;/layout&gt;
+  &lt;/head&gt;
+  &lt;body&gt;
+    &lt;div region="r1"&gt;
+      &lt;p begin="0s" end="8s"&gt;Lorem ipsum dolor sit&lt;/p
+      &lt;p begin="4s" end="12s"&gt;Amet consectetur adipiscing elit&lt;/p&gt;
+      &lt;p begin="8s" end="18s"&gt;Sed do eiusmod tempor incididunt labore&lt;/p&gt;
+      &lt;p begin="14s" end="25s"&gt;et dolore magna aliqua&lt;/p&gt;
+      &lt;p begin="18s" end="29s"&gt;Ut enim ad minim veniam quis, nostrud&lt;/p&gt;
+    &lt;/div&gt;
+  &lt;/body&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table></div><div class="div2">
+<h3><a id="paint-on-example"></a>P.3 Paint-On Caption Example</h3><p>An example of paint-on captions. Paint-on effects are achieved by using timed <code>span</code> elements in order to expose (paint) inline text units, e.g., words,
+over some time interval. Here, five paragraphs have their individual words sequentially timed in order to paint one new word every second. The end of the active duration of
+each inline element coincides with the end of the <code>div</code> element's parallel time container, so that once a word is painted, it remains in the region (on its rendered line) until the <code>div</code> element's active time interval lapses.</p><a id="paint-on-example-1-s"></a><table class="example"><caption>Example – Paint-On Captions</caption><tbody><tr><td>
+<div class="exampleInner"><pre>&lt;tt ttp:cellResolution="60 20" xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
+  xmlns:tts="http://www.w3.org/ns/ttml#parameter" xmlns:tts="http://www.w3.org/ns/ttml#styling"&gt;
+  &lt;head&gt;
+    &lt;layout&gt;
+      &lt;region xml:id="r1" tts:color="white" tts:origin="10c 4c" tts:extent="40c 5c"/&gt;
+    &lt;/layout&gt;
+  &lt;/head&gt;
+  &lt;body&gt;
+    &lt;div begin="0s" end="25s"&gt;
+      &lt;p&gt;
+        &lt;span begin="0s"&gt;Lorem&lt;/span&gt;
+        &lt;span begin="1s"&gt;ipsum&lt;/span&gt;
+        &lt;span begin="2s"&gt;dolor&lt;/span&gt;
+        &lt;span begin="3s"&gt;sit&lt;/span&gt;
+      &lt;/p&gt;
+      &lt;p&gt;
+        &lt;span begin="4s"&gt;Amet&lt;/span&gt;                
+        &lt;span begin="5s"&gt;consectetur&lt;/span&gt;
+        &lt;span begin="6s"&gt;adipiscing&lt;/span&gt;
+        &lt;span begin="7s"&gt;elit&lt;/span&gt;
+      &lt;/p&gt;
+      &lt;p&gt;
+        &lt;span begin="8s"&gt;Sed&lt;/span&gt;
+        &lt;span begin="9s"&gt;do&lt;/span&gt;
+        &lt;span begin="10s"&gt;eiusmod&lt;/span&gt;
+        &lt;span begin="11s"&gt;tempor&lt;/span&gt;
+        &lt;span begin="12s"&gt;incididunt &lt;/span&gt;
+        &lt;span begin="13s"&gt;labore&lt;/span&gt;
+     &lt;/p&gt;
+     &lt;p&gt;
+        &lt;span begin="14s"&gt;et&lt;/span&gt;
+        &lt;span begin="15s"&gt;dolore&lt;/span&gt;
+        &lt;span begin="16s"&gt;magna&lt;/span&gt;
+        &lt;span begin="17s"&gt;aliqua&lt;/span&gt;
+      &lt;/p&gt;
+      &lt;p&gt;
+        &lt;span begin="18s"&gt;Ut&lt;/span&gt;
+        &lt;span begin="19s"&gt;enim&lt;/span&gt;
+        &lt;span begin="20s"&gt;ad&lt;/span&gt;
+        &lt;span begin="21s"&gt;minim&lt;/span&gt;
+        &lt;span begin="22s"&gt;veniam&lt;/span&gt;
+        &lt;span begin="23s"&gt;quis,&lt;/span&gt;
+        &lt;span begin="24s"&gt;nostrud&lt;/span&gt;
+      &lt;/p&gt;
+    &lt;/div&gt;
+  &lt;/body&gt;
+&lt;/tt&gt;
+</pre></div>
+</td></tr></tbody></table></div></div><div class="div1">
+<h2><a id="cea708-mapping"></a>Q CEA708 Mapping Considerations (Non-Normative)</h2><p>This section provides additional information about mapping CEA708
+constructs to TTML.</p><table border="1" class="ednote" summary="Editorial note: CEA708 Mapping"><tr class="ednote-r1"><td align="left" valign="top"><b>Editorial note: CEA708 Mapping</b></td><td align="right" valign="top">2014-03-06</td></tr><tr class="ednote-r2"><td colspan="2" align="left" valign="top">Refer to ST2052-11 as starting point. Add additional considerations.</td></tr></table></div><div class="div1">
+<h2><a id="acknowledgments"></a>R Acknowledgments (Non-Normative)</h2><p>The editor acknowledges the current and former members of the Timed Text Working
+Group, the members of other W3C Working Groups, and industry experts
+in other forums who have contributed directly or indirectly to the
+process or content of this document as follows:</p><p>Glenn Adams,
+Thomas Bause-Mason,
+John Birch,
+Kees Blom,
+Bert Bos,
+Brad Botkin,
+Dick Bulterman,
+Frans de Jong,
+Mike Dolan,
+Martin Dürst,
+Donald Evans,
+Geoff Freed,
+Al Gilman,
+Giles Godart-Brown,
+Markus Gylling,
+Markku Hakkinen,
+Sean Hayes,
+Erik Hodge,
+Philipp Hoschka,
+Suzi Hyun,
+Michael Jordan,
+Masahiko Kaneko,
+Courtney Kennedy,
+George Kerscher,
+David Kirby,
+Andrew Kirkpatrick,
+Philippe Le Hégaret,
+Pierre-Anthony Lemieux,
+Chris Lilley,
+Jason Livingston,
+Monica Martin,
+Matthew May,
+Nigel Megitt,
+Thierry Michel,
+Frank Olivier,
+Soohong Daniel Park,
+Silvia Pfeiffer,
+Rohit Puri,
+Brian Raymor,
+David Ronca,
+Patrick Schmitz,
+David Singer,
+Craig Smithpeters,
+Andreas Tai,
+and Mohamed Zergaoui.
+</p><p>The editor wishes to especially acknowledge the following contributions
+by current and past members: Mike Dolan (SMPTE time codes, streaming; SMPTE liaison), David
+Kirby (introductory example document; SMPTE time codes, descriptive metadata; EBU/AAF liaison), Geoff Freed (styling
+and example images of style properties), Sean Hayes (advanced profile
+concepts, including applicative timing, HTML/CSS mapping proposal), Erik Hodge (timing),
+Thierry Michel (metadata), and Dave Singer (animation, scrolling).</p><p>The editor also wishes to acknowledge the support of the following current and past sponsors of his work
+on this specification: Cox Communications, Netflix, Microsoft, and Samsung Electronics.</p><p>The Working Group dedicates this specification to our colleague David Kirby.</p></div></div></body></html>
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