[ttml10se] prepare final PER archive ttml1-WD-20130709-PER
authorGlenn Adams <glenn@skynav.com>
Fri, 28 Jun 2013 00:19:59 -0600
changeset 418 2bdd57e9fc8f
parent 417 3757c307d61d
child 419 b9e9a2c34610
[ttml10se] prepare final PER archive
ttml10/spec/PER-ttaf1-dfxp-201305DD.html
ttml10/spec/PER-ttaf1-dfxp-201305DD.zip
ttml10/spec/PER-ttaf1-dfxp-20130709.zip
ttml10/spec/PER-ttaf1-dfxp-20130709/PER-ttaf1-dfxp-20130709.html
ttml10/spec/PER-ttaf1-dfxp-20130709/images/backgroundColor.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/color.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/direction.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/displayAlign.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/display_0.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/display_1.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/display_2.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/display_3.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/display_4.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/extent.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/fontFamily.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/fontSize.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/fontStyle.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/fontWeight.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/lineHeight.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/model.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/opacity_0.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/opacity_1.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/opacity_2.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/opacity_3.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/opacity_4.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/origin.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/overflow.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/padding.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/streaming.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle1.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle2.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle3.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle4.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle5.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle6.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle7.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle8.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/subtitle9.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/textAlign.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/textDecoration.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/textOutline.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/unicodeBidi.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/visibility_0.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/visibility_1.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/visibility_2.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/visibility_3.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/wrapOption.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/writingMode.png
ttml10/spec/PER-ttaf1-dfxp-20130709/images/zIndex.png
ttml10/spec/PER-ttaf1-dfxp-20130709/rnc/schema.zip
ttml10/spec/PER-ttaf1-dfxp-20130709/xsd/schema.zip
ttml10/spec/PER-ttaf1-dfxp-201307DD.html
ttml10/spec/PER-ttaf1-dfxp-201307DD.zip
ttml10/spec/build.xml
ttml10/spec/entities.dtd
ttml10/spec/entitiesper.dtd
ttml10/spec/statusper.xml
ttml10/spec/ttaf1-dfxp.html
ttml10/spec/ttaf1-dfxp.xml
--- a/ttml10/spec/PER-ttaf1-dfxp-201305DD.html	Thu Jun 27 10:35:37 2013 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,19945 +0,0 @@
-<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
-<html lang="en-us">
-<head>
-  <meta name="generator" content=
-  "HTML Tidy for Linux/x86 (vers 25 March 2009), see www.w3.org">
-  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-  <title>Timed Text Markup Language (TTML) 1.0 (Second Edition)</title>
-  <style type="text/css">
-  code           { font-family: monospace; }
-
-  div.constraint,
-  div.issue,
-  div.note,
-  div.notice     { margin-left: 2em; }
-
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-  ol.enumla      { list-style-type: lower-alpha; }
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-  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 }
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-  table.acronyms td.def { width: 65% }
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-  table.semantics { border: 0px solid black; width: 85%; border-collapse: collapse }
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-  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;
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-  .strong { font-weight: bold }
-  .reqattr { font-weight: bold }
-  .optattr { font-style: italic }
-  </style>
-  <link rel="stylesheet" type="text/css" href=
-  "http://www.w3.org/StyleSheets/TR/W3C-PER.css">
-</head>
-
-<body>
-  <div class="head">
-    <p><a href="http://www.w3.org/"><img src="http://www.w3.org/Icons/w3c_home" alt="W3C"
-    height="48" width="72"></a></p>
-
-    <h1><a id="title" name="title"></a>Timed Text Markup Language (TTML) 1.0 (Second
-    Edition)</h1>
-
-    <h2><a id="w3c-doctype" name="w3c-doctype"></a>W3C Proposed Edited Recommendation DD
-    May 2013</h2>
-
-    <dl>
-      <dt>This version:</dt>
-
-      <dd><a href=
-      "http://www.w3.org/TR/2013/PER-ttaf1-dfxp-201305DD/">http://www.w3.org/TR/2013/PER-ttaf1-dfxp-201305DD/</a></dd>
-
-      <dt>Latest version:</dt>
-
-      <dd><a href=
-      "http://www.w3.org/TR/ttaf1-dfxp/">http://www.w3.org/TR/ttaf1-dfxp/</a></dd>
-
-      <dt>Previous version:</dt>
-
-      <dd><a href=
-      "http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/">http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/</a></dd>
-
-      <dt>Editor:</dt>
-
-      <dd>Glenn Adams, Cox Communications, Inc.</dd>
-
-      <dt>Contributing Authors:</dt>
-
-      <dd>Mike Dolan, Invited Expert</dd>
-
-      <dd>Geoff Freed, WGBH National Center for Accessible Media</dd>
-
-      <dd>Sean Hayes, Microsoft</dd>
-
-      <dd>Erik Hodge, RealNetworks</dd>
-
-      <dd>David Kirby, British Broadcasting Corporation (BBC)</dd>
-
-      <dd>Thierry Michel, W3C</dd>
-
-      <dd>Dave Singer, Apple Computer</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=ttaf1-dfxp"><strong>translations</strong></a>.</p>
-
-    <p class="copyright"><a href=
-    "http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>&nbsp;©&nbsp;2013&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" name="abstract"></a>Abstract</h2>
-
-    <p>This document specifies the Timed Text Markup Language (TTML) 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="#smil21">[SMIL 2.1]</a>
-    document.</p>
-  </div>
-
-  <div>
-    <h2><a id="status" name="status"></a>Status of this Document</h2>
-
-    <p><em>This section describes the status of this document at the time of its
-    publication. Other documents may supersede this document. A list of current W3C
-    publications and the latest revision of this technical report can be found in the
-    <a href="http://www.w3.org/TR/">W3C technical reports index</a> at
-    http://www.w3.org/TR/.</em></p>
-
-    <p>This document, published on DD May 2013, is a <a href=
-    "http://www.w3.org/2005/10/Process-20051014/tr.html#ProposedEditedRec">Proposed
-    Edited Recommendation</a> of the W3C. This second edition is not a new version of
-    this specification; its purpose is to clarify a number of issues that have become
-    apparent since the first edition was published.</p>
-
-    <p>This document has been produced by the <a href=
-    "http://www.w3.org/AudioVideo/TT/">Timed Text (TT) Working Group</a> as part of the
-    W3C <a href="http://www.w3.org/2008/WebVideo/">Video in the Web Activity</a>,
-    following the procedures set out for the W3C <a href=
-    "http://www.w3.org/Consortium/Process/">Process</a>. The authors of this document are
-    listed in the header of this document.</p>
-
-    <p>Publication as a Proposed Edited Recommendation does not imply endorsement by the
-    W3C Membership. This is a draft document and may be updated, replaced or obsoleted by
-    other documents at any time. It is inappropriate to cite this document as other than
-    work in progress.</p>
-
-    <p>W3C Advisory Committee Members are invited to send formal review comments on this
-    Proposed Edited Recommendation to the W3C Team until DD June 2013. Members of the W3C
-    Advisory Committee will find the appropriate review form for this document by
-    consulting their <a href="http://www.w3.org/2002/09/wbs/myQuestionnaires">list of WBS
-    questionnaires</a>.</p>
-
-    <p>This document incorporates changes made against the <a href=
-    "http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/">Recommendation</a> of 18
-    November 2010 that resolve all errata known at the date of publication. A list of the
-    errata that have been applied is provided in <a href=
-    "https://dvcs.w3.org/hg/ttml/raw-file/default/ttml10/spec/ttml-changes.html#change-history-rec-to-2e-per">
-    Changes from Recommendation to Proposed Edited Recommendation (2nd Ed.)</a>.</p>
-
-    <p>Please report errors in and submit comments on this document to the W3C Timed Text
-    public comments mailing list, <a href=
-    "mailto:public-tt-comments@w3.org">public-tt-comments@w3.org</a>. Please include the
-    string <code>[ttml10se]</code> at the beginning of the subject line of your report.
-    Each email message should contain only one error report. Archives of the comments and
-    responses are available at <a href=
-    "http://lists.w3.org/Archives/Public/public-tt-comments/">http://lists.w3.org/Archives/Public/public-tt-comments/</a>.</p>
-
-    <p>An updated <a href="http://www.w3.org/2009/05/dfxp-results.html">implementation
-    report</a> will be made available, but the decision of the Director to transition
-    this document to Proposed Edited Recommendation did not depend on the existence of
-    that report.</p>
-
-    <p>The Timed Text Working Group plans to submit this specification for consideration
-    as a W3C Recommendation (Second Edition) as soon as the Working Group has responded
-    formally to all issues raised during the PER period against this document.</p>
-
-    <p>This document was produced by a group operating under the <a href=
-    "http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 W3C Patent
-    Policy</a>. W3C maintains a <a href=
-    "http://www.w3.org/2004/01/pp-impl/34314/status#disclosures" rel="disclosure">public
-    list of any patent disclosures</a> made in connection with the deliverables of the
-    group; that page also includes instructions for disclosing a patent. An individual
-    who has actual knowledge of a patent which the individual believes contains <a href=
-    "http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
-    Claim(s)</a> must disclose the information in accordance with <a href=
-    "http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of
-    the W3C Patent Policy</a>.</p>
-  </div>
-
-  <div class="toc">
-    <h2><a id="contents" name="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">Content
-    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</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-profiles">Profiles</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="#parameters">Parameters</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;6.1 <a href="#parameter-element-vocabulary">Parameter Element
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.1 <a href=
-    "#parameter-vocabulary-profile">ttp:profile</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.2 <a href=
-    "#parameter-vocabulary-features">ttp:features</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.3 <a href=
-    "#parameter-vocabulary-feature">ttp:feature</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.4 <a href=
-    "#parameter-vocabulary-extensions">ttp:extensions</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.1.5 <a href=
-    "#parameter-vocabulary-extension">ttp:extension</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;6.2 <a href="#parameter-attribute-vocabulary">Parameter
-    Attribute Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.1 <a href=
-    "#parameter-attribute-cellResolution">ttp:cellResolution</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.2 <a href=
-    "#parameter-attribute-clockMode">ttp:clockMode</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.3 <a href=
-    "#parameter-attribute-dropMode">ttp:dropMode</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.4 <a href=
-    "#parameter-attribute-frameRate">ttp:frameRate</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.5 <a href=
-    "#parameter-attribute-frameRateMultiplier">ttp:frameRateMultiplier</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.6 <a href=
-    "#parameter-attribute-markerMode">ttp:markerMode</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.7 <a href=
-    "#parameter-attribute-pixelAspectRatio">ttp:pixelAspectRatio</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.8 <a href=
-    "#parameter-attribute-profile">ttp:profile</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.9 <a href=
-    "#parameter-attribute-subFrameRate">ttp:subFrameRate</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.10 <a href=
-    "#parameter-attribute-tickRate">ttp:tickRate</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.2.11 <a href=
-    "#parameter-attribute-timeBase">ttp:timeBase</a><br>
-    7 <a href="#content">Content</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;7.1 <a href="#content-element-vocabulary">Content Element
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.1.1 <a href=
-    "#document-structure-vocabulary-tt">tt</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.1.2 <a href=
-    "#document-structure-vocabulary-head">head</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.1.3 <a href=
-    "#document-structure-vocabulary-body">body</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.1.4 <a href=
-    "#content-vocabulary-div">div</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.1.5 <a href=
-    "#content-vocabulary-p">p</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.1.6 <a href=
-    "#content-vocabulary-span">span</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.1.7 <a href=
-    "#content-vocabulary-br">br</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;7.2 <a href="#content-attribute-vocabulary">Content Attribute
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.1 <a href=
-    "#content-attribute-id">xml:id</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.2 <a href=
-    "#content-attribute-lang">xml:lang</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.2.3 <a href=
-    "#content-attribute-space">xml:space</a><br>
-    8 <a href="#styling">Styling</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;8.1 <a href="#styling-element-vocabulary">Styling Element
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.1 <a href=
-    "#styling-vocabulary-styling">styling</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.1.2 <a href=
-    "#styling-vocabulary-style">style</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;8.2 <a href="#styling-attribute-vocabulary">Styling Attribute
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.1 <a href=
-    "#style-attribute-style">style</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.2 <a href=
-    "#style-attribute-backgroundColor">tts:backgroundColor</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.3 <a href=
-    "#style-attribute-color">tts:color</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.4 <a href=
-    "#style-attribute-direction">tts:direction</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.5 <a href=
-    "#style-attribute-display">tts:display</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.6 <a href=
-    "#style-attribute-displayAlign">tts:displayAlign</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.7 <a href=
-    "#style-attribute-extent">tts:extent</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.8 <a href=
-    "#style-attribute-fontFamily">tts:fontFamily</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.9 <a href=
-    "#style-attribute-fontSize">tts:fontSize</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.10 <a href=
-    "#style-attribute-fontStyle">tts:fontStyle</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.11 <a href=
-    "#style-attribute-fontWeight">tts:fontWeight</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.12 <a href=
-    "#style-attribute-lineHeight">tts:lineHeight</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.13 <a href=
-    "#style-attribute-opacity">tts:opacity</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.14 <a href=
-    "#style-attribute-origin">tts:origin</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.15 <a href=
-    "#style-attribute-overflow">tts:overflow</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.16 <a href=
-    "#style-attribute-padding">tts:padding</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.17 <a href=
-    "#style-attribute-showBackground">tts:showBackground</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.18 <a href=
-    "#style-attribute-textAlign">tts:textAlign</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.19 <a href=
-    "#style-attribute-textDecoration">tts:textDecoration</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.20 <a href=
-    "#style-attribute-textOutline">tts:textOutline</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.21 <a href=
-    "#style-attribute-unicodeBidi">tts:unicodeBidi</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.22 <a href=
-    "#style-attribute-visibility">tts:visibility</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.23 <a href=
-    "#style-attribute-wrapOption">tts:wrapOption</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.24 <a href=
-    "#style-attribute-writingMode">tts:writingMode</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.2.25 <a href=
-    "#style-attribute-zIndex">tts:zIndex</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;8.3 <a href="#styling-style-value-expressions">Style Value
-    Expressions</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.1 <a href=
-    "#style-value-alpha">&lt;alpha&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.2 <a href=
-    "#style-value-color">&lt;color&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.3 <a href=
-    "#style-value-digit">&lt;digit&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.4 <a href=
-    "#style-value-duration">&lt;duration&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.5 <a href=
-    "#style-value-familyName">&lt;familyName&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.6 <a href=
-    "#style-value-genericFamilyName">&lt;genericFamilyName&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.7 <a href=
-    "#style-value-hexDigit">&lt;hexDigit&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.8 <a href=
-    "#style-value-integer">&lt;integer&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.9 <a href=
-    "#style-value-length">&lt;length&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.10 <a href=
-    "#style-value-namedColor">&lt;namedColor&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.11 <a href=
-    "#style-value-quotedString">&lt;quotedString&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.12 <a href=
-    "#style-value-string">&lt;string&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;8.4 <a href="#semantics-style-resolution">Style
-    Resolution</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.1 <a href=
-    "#semantics-style-association">Style Association</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.1.1
-    <a href="#semantics-style-association-inline">Inline Styling</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.1.2
-    <a href="#semantics-style-association-referential">Referential Styling</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.1.3
-    <a href="#semantics-style-association-chained-referential">Chained Referential
-    Styling</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.1.4
-    <a href="#semantics-style-association-nested">Nested Styling</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.2 <a href=
-    "#semantics-style-inheritance">Style Inheritance</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.2.1
-    <a href="#semantics-style-inheritance-content">Content Style Inheritance</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.2.2
-    <a href="#semantics-style-inheritance-region">Region Style Inheritance</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.3 <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;8.4.3.1
-    <a href="#semantics-style-resolved-value-category-specified">Specified Values</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.3.2
-    <a href="#semantics-style-resolved-value-category-computed">Computed Values</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.3.3
-    <a href="#semantics-style-resolved-value-category-actual">Actual Values</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.4 <a href=
-    "#semantics-style-resolution-processing">Style Resolution Processing</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.4.1
-    <a href="#semantics-style-resolution-processing-definitions">Conceptual
-    Definitions</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.4.4.2
-    <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;8.4.4.3
-    <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;8.4.4.4
-    <a href="#semantics-style-resolution-process-overall">Style Resolution
-    Process</a><br>
-    9 <a href="#layout">Layout</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;9.1 <a href="#layout-element-vocabulary">Layout Element
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.1 <a href=
-    "#layout-vocabulary-layout">layout</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.1.2 <a href=
-    "#layout-vocabulary-region">region</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;9.2 <a href="#layout-attribute-vocabulary">Layout Attribute
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.2.1 <a href=
-    "#layout-attribute-region">region</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;9.3 <a href="#semantics-region-layout">Region Layout and
-    Presentation</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.1 <a href=
-    "#semantics-default-region">Default Region</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.2 <a href=
-    "#semantics-region-layout-step-1">Intermediate Synchronic Document
-    Construction</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.3 <a href=
-    "#semantics-region-layout-step-2">Synchronic Flow Processing</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.3.4 <a href=
-    "#semantics-region-layout-example">Elaborated Example (Informative)</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;9.4 <a href="#semantics-line-layout">Line Layout</a><br>
-    10 <a href="#timing">Timing</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;10.1 <a href="#timing-element-vocabulary">Timing Element
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;10.2 <a href="#timing-attribute-vocabulary">Timing Attribute
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.1 <a href=
-    "#timing-attribute-begin">begin</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.2 <a href=
-    "#timing-attribute-end">end</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.3 <a href=
-    "#timing-attribute-dur">dur</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.2.4 <a href=
-    "#timing-attribute-timeContainer">timeContainer</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;10.3 <a href="#timing-time-value-expressions">Time Value
-    Expressions</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.3.1 <a href=
-    "#timing-value-timeExpression">&lt;timeExpression&gt;</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;10.4 <a href="#timing-time-intervals">Time Intervals</a><br>
-    11 <a href="#animation">Animation</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;11.1 <a href="#animation-element-vocabulary">Animation
-    Element Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.1.1 <a href=
-    "#animation-vocabulary-set">set</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;11.2 <a href="#animation-attribute-vocabulary">Animation
-    Attribute Vocabulary</a><br>
-    12 <a href="#metadata">Metadata</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;12.1 <a href="#metadata-element-vocabulary">Metadata Element
-    Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.1.1 <a href=
-    "#metadata-vocabulary-metadata">metadata</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.1.2 <a href=
-    "#metadata-vocabulary-title">ttm:title</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.1.3 <a href=
-    "#metadata-vocabulary-desc">ttm:desc</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.1.4 <a href=
-    "#metadata-vocabulary-copyright">ttm:copyright</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.1.5 <a href=
-    "#metadata-vocabulary-agent">ttm:agent</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.1.6 <a href=
-    "#metadata-vocabulary-name">ttm:name</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.1.7 <a href=
-    "#metadata-vocabulary-actor">ttm:actor</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;12.2 <a href="#metadata-attribute-vocabulary">Metadata
-    Attribute Vocabulary</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.1 <a href=
-    "#metadata-attribute-agent">ttm:agent</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.2.2 <a href=
-    "#metadata-attribute-role">ttm:role</a><br></p>
-
-    <h3><a id="appendices" name="appendices"></a>Appendices</h3>
-
-    <p class="toc">A <a href="#reduced-infoset">Reduced XML Infoset</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;A.1 <a href="#reduced-infoset-document">Document Information
-    Item</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;A.2 <a href="#reduced-infoset-element">Element Information
-    Item</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;A.3 <a href="#reduced-infoset-attribute">Attribute
-    Information Item</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;A.4 <a href="#reduced-infoset-character">Character
-    Information Item</a><br>
-    B <a href="#schemas">Schemas</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;B.1 <a href="#ttml-schema-rnc">Relax NG Compact (RNC)
-    Schema</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;B.2 <a href="#ttml-schema-xsd">XML Schema Definition (XSD)
-    Schema</a><br>
-    C <a href="#media-types-registration">Media Type Registration</a><br>
-    D <a href="#features">Features</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;D.1 <a href="#feature-designations">Feature
-    Designations</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.1 <a href=
-    "#feature-animation">#animation</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.2 <a href=
-    "#feature-backgroundColor">#backgroundColor</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.3 <a href=
-    "#feature-backgroundColor-block">#backgroundColor-block</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.4 <a href=
-    "#feature-backgroundColor-inline">#backgroundColor-inline</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.5 <a href=
-    "#feature-backgroundColor-region">#backgroundColor-region</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.6 <a href=
-    "#feature-bidi">#bidi</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.7 <a href=
-    "#feature-cellResolution">#cellResolution</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.8 <a href=
-    "#feature-clockMode">#clockMode</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.9 <a href=
-    "#feature-clockMode-gps">#clockMode-gps</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.10 <a href=
-    "#feature-clockMode-local">#clockMode-local</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.11 <a href=
-    "#feature-clockMode-utc">#clockMode-utc</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.12 <a href=
-    "#feature-color">#color</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.13 <a href=
-    "#feature-content">#content</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.14 <a href=
-    "#feature-core">#core</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.15 <a href=
-    "#feature-direction">#direction</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.16 <a href=
-    "#feature-display">#display</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.17 <a href=
-    "#feature-display-block">#display-block</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.18 <a href=
-    "#feature-display-inline">#display-inline</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.19 <a href=
-    "#feature-display-region">#display-region</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.20 <a href=
-    "#feature-displayAlign">#displayAlign</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.21 <a href=
-    "#feature-dropMode">#dropMode</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.22 <a href=
-    "#feature-dropMode-dropNTSC">#dropMode-dropNTSC</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.23 <a href=
-    "#feature-dropMode-dropPAL">#dropMode-dropPAL</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.24 <a href=
-    "#feature-dropMode-nonDrop">#dropMode-nonDrop</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.25 <a href=
-    "#feature-extent">#extent</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.26 <a href=
-    "#feature-extent-region">#extent-region</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.27 <a href=
-    "#feature-extent-root">#extent-root</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.28 <a href=
-    "#feature-fontFamily">#fontFamily</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.29 <a href=
-    "#feature-fontFamily-generic">#fontFamily-generic</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.30 <a href=
-    "#feature-fontFamily-non-generic">#fontFamily-non-generic</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.31 <a href=
-    "#feature-fontSize">#fontSize</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.32 <a href=
-    "#feature-fontSize-anamorphic">#fontSize-anamorphic</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.33 <a href=
-    "#feature-fontSize-isomorphic">#fontSize-isomorphic</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.34 <a href=
-    "#feature-fontStyle">#fontStyle</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.35 <a href=
-    "#feature-fontStyle-italic">#fontStyle-italic</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.36 <a href=
-    "#feature-fontStyle-oblique">#fontStyle-oblique</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.37 <a href=
-    "#feature-fontWeight">#fontWeight</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.38 <a href=
-    "#feature-fontWeight-bold">#fontWeight-bold</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.39 <a href=
-    "#feature-frameRate">#frameRate</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.40 <a href=
-    "#feature-frameRateMultiplier">#frameRateMultiplier</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.41 <a href=
-    "#feature-layout">#layout</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.42 <a href=
-    "#feature-length">#length</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.43 <a href=
-    "#feature-length-cell">#length-cell</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.44 <a href=
-    "#feature-length-em">#length-em</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.45 <a href=
-    "#feature-length-integer">#length-integer</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.46 <a href=
-    "#feature-length-negative">#length-negative</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.47 <a href=
-    "#feature-length-percentage">#length-percentage</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.48 <a href=
-    "#feature-length-pixel">#length-pixel</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.49 <a href=
-    "#feature-length-positive">#length-positive</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.50 <a href=
-    "#feature-length-real">#length-real</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.51 <a href=
-    "#feature-lineBreak-uax14">#lineBreak-uax14</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.52 <a href=
-    "#feature-lineHeight">#lineHeight</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.53 <a href=
-    "#feature-markerMode">#markerMode</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.54 <a href=
-    "#feature-markerMode-continuous">#markerMode-continuous</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.55 <a href=
-    "#feature-markerMode-discontinuous">#markerMode-discontinuous</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.56 <a href=
-    "#feature-metadata">#metadata</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.57 <a href=
-    "#feature-nested-div">#nested-div</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.58 <a href=
-    "#feature-nested-span">#nested-span</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.59 <a href=
-    "#feature-opacity">#opacity</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.60 <a href=
-    "#feature-origin">#origin</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.61 <a href=
-    "#feature-overflow">#overflow</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.62 <a href=
-    "#feature-overflow-visible">#overflow-visible</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.63 <a href=
-    "#feature-padding">#padding</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.64 <a href=
-    "#feature-padding-1">#padding-1</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.65 <a href=
-    "#feature-padding-2">#padding-2</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.66 <a href=
-    "#feature-padding-3">#padding-3</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.67 <a href=
-    "#feature-padding-4">#padding-4</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.68 <a href=
-    "#feature-pixelAspectRatio">#pixelAspectRatio</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.69 <a href=
-    "#feature-presentation">#presentation</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.70 <a href=
-    "#feature-profile">#profile</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.71 <a href=
-    "#feature-showBackground">#showBackground</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.72 <a href=
-    "#feature-structure">#structure</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.73 <a href=
-    "#feature-styling">#styling</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.74 <a href=
-    "#feature-styling-chained">#styling-chained</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.75 <a href=
-    "#feature-styling-inheritance-content">#styling-inheritance-content</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.76 <a href=
-    "#feature-styling-inheritance-region">#styling-inheritance-region</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.77 <a href=
-    "#feature-styling-inline">#styling-inline</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.78 <a href=
-    "#feature-styling-nested">#styling-nested</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.79 <a href=
-    "#feature-styling-referential">#styling-referential</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.80 <a href=
-    "#feature-subFrameRate">#subFrameRate</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.81 <a href=
-    "#feature-textAlign">#textAlign</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.82 <a href=
-    "#feature-textAlign-absolute">#textAlign-absolute</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.83 <a href=
-    "#feature-textAlign-relative">#textAlign-relative</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.84 <a href=
-    "#feature-textDecoration">#textDecoration</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.85 <a href=
-    "#feature-textDecoration-over">#textDecoration-over</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.86 <a href=
-    "#feature-textDecoration-through">#textDecoration-through</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.87 <a href=
-    "#feature-textDecoration-under">#textDecoration-under</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.88 <a href=
-    "#feature-textOutline">#textOutline</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.89 <a href=
-    "#feature-textOutline-blurred">#textOutline-blurred</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.90 <a href=
-    "#feature-textOutline-unblurred">#textOutline-unblurred</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.91 <a href=
-    "#feature-tickRate">#tickRate</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.92 <a href=
-    "#feature-timeBase-clock">#timeBase-clock</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.93 <a href=
-    "#feature-timeBase-media">#timeBase-media</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.94 <a href=
-    "#feature-timeBase-smpte">#timeBase-smpte</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.95 <a href=
-    "#feature-timeContainer">#timeContainer</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.96 <a href=
-    "#feature-time-clock">#time-clock</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.97 <a href=
-    "#feature-time-clock-with-frames">#time-clock-with-frames</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.98 <a href=
-    "#feature-time-offset">#time-offset</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.99 <a href=
-    "#feature-time-offset-with-frames">#time-offset-with-frames</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.100 <a href=
-    "#feature-time-offset-with-ticks">#time-offset-with-ticks</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.101 <a href=
-    "#feature-timing">#timing</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.102 <a href=
-    "#feature-transformation">#transformation</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.103 <a href=
-    "#feature-unicodeBidi">#unicodeBidi</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.104 <a href=
-    "#feature-visibility">#visibility</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.105 <a href=
-    "#feature-visibility-block">#visibility-block</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.106 <a href=
-    "#feature-visibility-inline">#visibility-inline</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.107 <a href=
-    "#feature-visibility-region">#visibility-region</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.108 <a href=
-    "#feature-wrapOption">#wrapOption</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.109 <a href=
-    "#feature-writingMode">#writingMode</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.110 <a href=
-    "#feature-writingMode-vertical">#writingMode-vertical</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.111 <a href=
-    "#feature-writingMode-horizontal">#writingMode-horizontal</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.112 <a href=
-    "#feature-writingMode-horizontal-lr">#writingMode-horizontal-lr</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.113 <a href=
-    "#feature-writingMode-horizontal-rl">#writingMode-horizontal-rl</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;D.1.114 <a href=
-    "#feature-zIndex">#zIndex</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;D.2 <a href="#feature-support">Feature Support</a><br>
-    E <a href="#extensions">Extensions</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;E.1 <a href="#extension-designations">Extension
-    Designations</a><br>
-    F <a href="#profiles">Profiles</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;F.1 <a href="#profile-dfxp-transformation">DFXP
-    Transformation Profile</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;F.2 <a href="#profile-dfxp-presentation">DFXP Presentation
-    Profile</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;F.3 <a href="#profile-dfxp-full">DFXP Full Profile</a><br>
-    G <a href="#references">References</a><br>
-    H <a href="#other-references">Other References</a> (Non-Normative)<br>
-    I <a href="#requirements">Requirements</a> (Non-Normative)<br>
-    J <a href="#derivation">Vocabulary Derivation</a> (Non-Normative)<br>
-    &nbsp;&nbsp;&nbsp;&nbsp;J.1 <a href="#d3e18280">Element Derivation</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;J.2 <a href="#d3e18759">Attribute Derivation</a><br>
-    K <a href="#qa">QA Framework Compliance</a> (Non-Normative)<br>
-    &nbsp;&nbsp;&nbsp;&nbsp;K.1 <a href="#d3e19629">Requirements</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;K.2 <a href="#d3e19793">Guidelines</a><br>
-    L <a href="#streaming">Streaming TTML Content</a> (Non-Normative)<br>
-    M <a href="#concrete-encoding">Concrete Encoding</a> (Non-Normative)<br>
-    N <a href="#time-expression-semantics">Time Expression Semantics</a>
-    (Non-Normative)<br>
-    &nbsp;&nbsp;&nbsp;&nbsp;N.1 <a href="#time-expression-semantics-clock">Clock Time
-    Base</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;N.2 <a href="#time-expression-semantics-media">Media Time
-    Base</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;N.3 <a href="#time-expression-semantics-smpte">SMPTE Time
-    Base</a><br>
-    O <a href="#common-styling">Common Caption Style Examples</a> (Non-Normative)<br>
-    &nbsp;&nbsp;&nbsp;&nbsp;O.1 <a href="#pop-on-example">Pop-On Caption Example</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;O.2 <a href="#roll-up-example">Roll-Up Caption
-    Example</a><br>
-    &nbsp;&nbsp;&nbsp;&nbsp;O.3 <a href="#paint-on-example">Paint-On Caption
-    Example</a><br>
-    P <a href="#acknowledgments">Acknowledgments</a> (Non-Normative)<br></p>
-  </div>
-  <hr>
-
-  <div class="body">
-    <div class="div1">
-      <h2><a id="intro" name="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) 1.0 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>I 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 (as implied by
-      the acronym DFXP), 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="#smil21">[SMIL 2.1]</a> document. Certain properties of TTML support
-      streamability of content, as described in <a href="#streaming"><b>L Streaming TTML
-      Content</b></a>.</p>
-
-      <div class="note">
-        <p class="prefix"><b>Note:</b></p>
-
-        <p>While TTML was 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 <em>Document Instance</em>. 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" name="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" name="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>
-      </div>
-
-      <div class="div2">
-        <h3><a id="example" name="example"></a>1.2 Document Example</h3>
-
-        <p>A TTML <em>Document Instance</em> 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" name="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" name=
-        "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" name=
-        "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" name=
-        "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 <em>Document Instance</em> 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" name=
-        "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><a id="ttml-example-subtitle-1" name="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
-        affect 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" name="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" name="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" name="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" name="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" name=
-        "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" name="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" name="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" name="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
-        <em>Document Instance</em>. 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" name="definitions"></a>2 Definitions</h2>
-
-      <div class="div2">
-        <h3><a id="acronyms" name="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>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>TT AS</b></td>
-
-            <td class="def">
-              <p>Timed Text Authoring System</p>
-            </td>
-          </tr>
-
-          <tr>
-            <td class="label"><b>TT AF</b></td>
-
-            <td class="def">
-              <p>Timed Text Authoring Format</p>
-            </td>
-          </tr>
-
-          <tr>
-            <td class="label"><b>TT WG</b></td>
-
-            <td class="def">
-              <p>Timed Text Working Group</p>
-            </td>
-          </tr>
-        </table>
-      </div>
-
-      <div class="div2">
-        <h3><a id="terms" name="terms"></a>2.2 Terminology</h3>
-
-        <dl>
-          <dt class="label">Abstract Document Instance</dt>
-
-          <dd>
-            <p>An instance of an abstract data set as represented by a <em>Reduced XML
-            Infoset</em>.</p>
-          </dd>
-
-          <dt class="label">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">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">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">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">Content Profile</dt>
-
-          <dd>
-            <p>A collection of features and extensions that are (or may be) employed by
-            Timed Text Markup Language content.</p>
-          </dd>
-
-          <dt class="label">Content Region</dt>
-
-          <dd>
-            <p>A logical region into which rendered content is placed when modeling or
-            performing presentation processing.</p>
-          </dd>
-
-          <dt class="label">Document Instance</dt>
-
-          <dd>
-            <p>A concrete realization of a Timed Text Markup Language document, where the
-            concrete form is specific to the context of reference. For example, a
-            sequence of bytes that represents an XML serialization of a Timed Text
-            document, an internal, parsed representation of such a Timed Text document,
-            etc.</p>
-          </dd>
-
-          <dt class="label">Document Interchange Context</dt>
-
-          <dd>
-            <p>The implied context or environment external to a <em>Content
-            Processor</em> in which document interchange occurs, and in which out-of-band
-            protocols or specifications may define certain behavioral defaults, such as
-            an implied <em>Content Profile</em>.</p>
-          </dd>
-
-          <dt class="label">Document Processing Context</dt>
-
-          <dd>
-            <p>The implied context or environment internal to a <em>Content
-            Processor</em> 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 <em>Synthetic Document Syncbase</em>.</p>
-          </dd>
-
-          <dt class="label">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">Exchange Profile</dt>
-
-          <dd>
-            <p>A content profile that serves a set of needs for content interchange.</p>
-          </dd>
-
-          <dt class="label">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">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 future
-            revision of this specification).</p>
-          </dd>
-
-          <dt class="label">Presentation Processor</dt>
-
-          <dd>
-            <p>A <em>Content Processor</em> which purpose is to layout, format, and
-            render, i.e., to present, <em>Timed Text Markup Language</em> content by
-            applying the presentation semantics defined in this specification.</p>
-          </dd>
-
-          <dt class="label">Processor</dt>
-
-          <dd>
-            <p>See <em>Content Processor</em>.</p>
-          </dd>
-
-          <dt class="label">Processor Profile</dt>
-
-          <dd>
-            <p>A collection of features and extensions that must or may be implemented
-            (supported) by a content processor.</p>
-          </dd>
-
-          <dt class="label">Profile Definition Document</dt>
-
-          <dd>
-            <p>A document that defines a specific collection of features and extensions
-            for which support is required or optional in a recipient content
-            processor.</p>
-          </dd>
-
-          <dt class="label">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">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>A Reduced XML
-            Infoset</b></a>.</p>
-          </dd>
-
-          <dt class="label">Related Media Object</dt>
-
-          <dd>
-            <p>A (possibly null) media object associated with or otherwise related to a
-            <em>Document Instance</em>. For example, an aggregate audio/video media
-            object for which a <em>Document Instance</em> provides caption or subtitle
-            information, and with which that <em>Document Instance</em> is
-            associated.</p>
-          </dd>
-
-          <dt class="label">Root Container Region</dt>
-
-          <dd>
-            <p>A logical region that establishes a coordinate system into which
-            <em>Document Instance</em> content regions are placed and optionally
-            clipped.</p>
-          </dd>
-
-          <dt class="label">Root Temporal Extent</dt>
-
-          <dd>
-            <p>The temporal extent (interval) defined by the temporal beginning and
-            ending of a <em>Document Instance</em> in relationship with some external
-            application or presentation context.</p>
-          </dd>
-
-          <dt class="label">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">Synthetic Document Syncbase</dt>
-
-          <dd>
-            <p>A document level <a href=
-            "http://www.w3.org/TR/2005/REC-SMIL2-20051213/smil-timing.html#Timing-Syncbases">
-            syncbase</a> <a href="#smil21">[SMIL 2.1]</a>, § 10.7.1, synthesized or
-            otherwise established by the <em>Document Processing Context</em> in
-            accordance with the <em>Related Media Object</em> or other processing
-            criteria.</p>
-          </dd>
-
-          <dt class="label">Synthetic SMPTE Document Syncbase</dt>
-
-          <dd>
-            <p>A <em>Synthetic Document Syncbase</em> constructed from <em>SMPTE Time
-            Code</em> values embedded in or associated with the <em>Related Media
-            Object</em> or otherwise determined by the <em>Document Processing
-            Context</em>.</p>
-          </dd>
-
-          <dt class="label">Timed Text</dt>
-
-          <dd>
-            <p>Textual information that is intrinsically or extrinsically associated with
-            timing information.</p>
-          </dd>
-
-          <dt class="label">Timed Text Markup Language</dt>
-
-          <dd>
-            <p>A content type that represents timed text media for the purpose of
-            interchange among authoring systems.</p>
-          </dd>
-
-          <dt class="label">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">Transformation Processor</dt>
-
-          <dd>
-            <p>A <em>Content Processor</em> which purpose is to transform or otherwise
-            rewrite <em>Timed Text Markup Language</em> content to either <em>Timed Text
-            Markup Language</em> 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">Valid Abstract Document Instance</dt>
-
-          <dd>
-            <p>An <em>Abstract Document Instance</em> 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>
-        </dl>
-      </div>
-
-      <div class="div2">
-        <h3><a id="conventions" name="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" name="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> = integer
-  size = (<em>large</em>|<em>medium</em>|<em>small</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 attribute information item 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>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>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" name="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>
-      </div>
-    </div>
-
-    <div class="div1">
-      <h2><a id="conformance" name="conformance"></a>3 Conformance</h2>
-
-      <p>This section specifies the general conformance requirements for TTML Content and
-      processors.</p>
-
-      <div class="div2">
-        <h3><a id="conformance-content" name="conformance-content"></a>3.1 Content
-        Conformance</h3>
-
-        <p>A TTML <em>Document Instance</em> conforms to this specification if the
-        following criteria are satisfied:</p>
-
-        <ol class="enumar">
-          <li>
-            <p>When transporting a <em>Document Instance</em> in a <em>Document
-            Interchange Context</em> in which a Media Type <a href="#media-types">[Media
-            Types]</a> identifies the content type of the interchanged <em>Document
-            Instance</em>, then the specified media type is
-            <code>application/ttml+xml</code> in conformance with <a href="#rfc3023">[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-profiles"><b>5.2 Profiles</b></a>.</p>
-          </li>
-
-          <li>
-            <p>The <em>Document Instance</em> is or can be represented as a Reduced XML
-            Infoset as defined by <a href="#reduced-infoset"><b>A Reduced XML
-            Infoset</b></a>.</p>
-          </li>
-
-          <li>
-            <p>The Reduced XML Infoset that corresponds to the <em>Document Instance</em>
-            is or can be associated 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 <em>Reduced XML Infoset</em> that corresponds to the <em>Document
-            Instance</em> is a <em>Valid Abstract Document Instance</em> of the
-            associated <em>Abstract Document Type</em>.</p>
-          </li>
-
-          <li>
-            <p>The <em>Reduced XML Infoset</em> 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" name="conformance-processor"></a>3.2 Processor
-        Conformance</h3>
-
-        <div class="div3">
-          <h4><a id="conformance-generic-processor" name=
-          "conformance-generic-processor"></a>3.2.1 Generic Processor Conformance</h4>
-
-          <p>A TTML <em>Content Processor</em> 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 Reduced XML Infoset representation of a conformant
-              <em>Document Instance</em>.</p>
-            </li>
-
-            <li>
-              <p>If a process does or can perform validation of a candidate <em>Document
-              Instance</em>, then it provides at least one mechanism to implicitly or
-              explicitly associate the <em>Reduced XML Infoset</em> representation of a
-              conformant <em>Document Instance</em> 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 <em>Document Instance</em> unless the processor does not
-              support some required (mandatory) feature specified or implied by a TTML
-              Content profile declared to apply to the <em>Document Instance</em>.</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>D.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>D.2 Feature
-                Support</b></a>.</p>
-              </div>
-            </li>
-          </ol>
-        </div>
-
-        <div class="div3">
-          <h4><a id="conformance-transformation-processor" name=
-          "conformance-transformation-processor"></a>3.2.2 Transformation Processor
-          Conformance</h4>
-
-          <p>A TTML <em>Content Processor</em> is a conformant TTML <em>Transformation
-          Processor</em> 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 DFXP Transformation profile as specified by
-              <a href="#profile-dfxp-transformation"><b>F.1 DFXP Transformation
-              Profile</b></a>.</p>
-            </li>
-          </ol>
-        </div>
-
-        <div class="div3">
-          <h4><a id="conformance-presentation-processor" name=
-          "conformance-presentation-processor"></a>3.2.3 Presentation Processor
-          Conformance</h4>
-
-          <p>A TTML <em>Content Processor</em> is a conformant TTML <em>Presentation
-          Processor</em> 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 DFXP Presentation profile as specified by
-              <a href="#profile-dfxp-presentation"><b>F.2 DFXP Presentation
-              Profile</b></a>.</p>
-            </li>
-          </ol>
-        </div>
-      </div>
-
-      <div class="div2">
-        <h3><a id="claims" name="claims"></a>3.3 Claims</h3>
-
-        <p>Any claim of compliance with respect to the conformance of a TTML <em>Document
-        Instance</em> or <em>Content Processor</em> 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-profiles"><b>5.2 Profiles</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 <em>Document Instance</em> 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="#parameter-attribute-profile"><b>6.2.8
-        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=
-        "#parameter-vocabulary-profile"><b>6.1.1 ttp:profile</b></a>.</p>
-      </div>
-    </div>
-
-    <div class="div1">
-      <h2><a id="doctypes" name="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</b></a></p>
-        </li>
-      </ul>
-
-      <p>Each <em>Abstract Document Type</em> 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 <em>Abstract Document Instance</em> may be assessed in terms of validity, and
-      is considered to be a <em>Valid Abstract Document Instance</em> 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 <em>Abstract Document
-          Type</em>, 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
-          <em>Abstract Document Type</em>, 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 1 – Namespaces</b></a>,</p>
-        </li>
-      </ol>
-
-      <p>then the document element is one of the document element types permitted by the
-      associated <em>Abstract Document Type</em>, 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 <em>Abstract Document Type</em>.</p>
-
-      <div class="note">
-        <p class="prefix"><b>Note:</b></p>
-
-        <p>While a conformant processor may not <em>a priori</em> reject a conformant
-        <em>Document Instance</em> that adheres to a supported content profile, a given
-        <em>Document Instance</em> 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" name="ttml-content-doctype"></a>4.1 TTML
-        Content</h3>
-
-        <p>TTML Content is an <em>Abstract Document Type</em> 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 conformant TTML Content <em>Document
-        Instances</em>:</p>
-
-        <ul>
-          <li>
-            <p><a href="#ttml-schema-rnc"><b>B.1 Relax NG Compact (RNC)
-            Schema</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#ttml-schema-xsd"><b>B.2 XML Schema Definition (XSD)
-            Schema</b></a></p>
-          </li>
-        </ul>
-
-        <p>The (root) document element of a TTML Content <em>Document Instance</em> must
-        be a <code>tt</code> element, as defined by <a href=
-        "#document-structure-vocabulary-tt"><b>7.1.1 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>xs: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 <em>Document Instance</em> to be
-          based on an <em>Abstract Document Instance</em> 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
-          <em>Document Instance</em> validity.</p>
-        </div>
-      </div>
-    </div>
-
-    <div class="div1">
-      <h2><a id="vocabulary" name="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-profiles"><b>5.2 Profiles</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" name="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 <em>Document Instance</em>, 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" name="namespace-vocab-table"></a>
-
-        <table class="common">
-          <caption>
-            Table 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 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>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-profiles" name="vocabulary-profiles"></a>5.2 Profiles</h3>
-
-        <p>The Timed Text Markup Language (TTML) employs a number of standard, predefined
-        profiles of its vocabulary and associated semantics. 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="#profiles"><b>F Profiles</b></a>.</p><a id="profile-vocab-table"
-        name="profile-vocab-table"></a>
-
-        <table class="common">
-          <caption>
-            Table 2 – Profiles
-          </caption>
-          <col width="25%" span="1">
-          <col span="1">
-
-          <tbody>
-            <tr>
-              <th>Name</th>
-
-              <th>Designator</th>
-            </tr>
-
-            <tr>
-              <td>DFXP Transformation</td>
-
-              <td><code>http://www.w3.org/ns/ttml/profile/dfxp-transformation</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 Full</td>
-
-              <td><code>http://www.w3.org/ns/ttml/profile/dfxp-full</code></td>
-            </tr>
-          </tbody>
-        </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>dfxp-presentation</code>, then the absolutized profile designator would
-          be <code>http://www.w3.org/ns/ttml/profile/dfxp-presentation</code>.</p>
-        </div>
-
-        <p>A profile designator is not restricted to the set of designators enumerated in
-        <a href="#profile-vocab-table"><b>Table 2 – Profiles</b></a>, but may be any URI
-        that feasibly dereferences a TTML <em>Profile Definition Document</em>.</p>
-
-        <p>The profile of TTML that must be supported by a TTML <em>Content
-        Processor</em> in order to process a <em>Document Instance</em> is determined
-        either (1) by specifying a <code>ttp:profile</code> attribute on the root
-        <code>tt</code> element, as defined by <a href=
-        "#parameter-attribute-profile"><b>6.2.8 ttp:profile</b></a>, or (2) by including
-        one or more <code>ttp:profile</code> elements in the <code>head</code> element,
-        in accordance with <a href="#parameter-vocabulary-profile"><b>6.1.1
-        ttp:profile</b></a>.</p>
-
-        <p>If a <code>ttp:profile</code> element appears as a descendant of the
-        <code>tt</code> element, then the <a href=
-        "#parameter-attribute-profile"><code>ttp:profile</code></a> attribute should not
-        be specified on the <code>tt</code> element. If both a <code>ttp:profile</code>
-        element and a <code>ttp:profile</code> attribute are present (in a given
-        <em>Document Instance</em>), then the <code>ttp:profile</code> attribute must be
-        ignored for the purpose of determining the declared profile requirements.</p>
-
-        <p>If more than one <code>ttp:profile</code> element appears in a <em>Document
-        Instance</em>, then all specified profiles apply simultaneously. In such a case,
-        if some feature or some extension is specified by one profile to be used
-        (mandatory and enabled) and by another profile to be required (mandatory) or
-        optional (voluntary), then that feature or extension must be considered to be
-        used (mandatory and enabled); if some feature or some extension is specified by
-        one profile to be merely required (mandatory) and by another profile to be
-        optional (voluntary), then that feature or extension must be considered to be
-        required (mandatory).</p>
-
-        <p>If neither <a href="#parameter-attribute-profile"><code>ttp:profile</code></a>
-        attribute nor <a href=
-        "#parameter-vocabulary-profile"><code>ttp:profile</code></a> element is present
-        in a <em>Document Instance</em>, and if the <em>Document Interchange Context</em>
-        does not make an implicit or explicit reference to a pre-defined Content Profile
-        or does not specify a <em>Profile Definition Document</em> or another equivalent
-        set of feature designations, then the DFXP Transformation profile applies.</p>
-
-        <div class="note">
-          <p class="prefix"><b>Note:</b></p>
-
-          <p>It is not a requirement on a conformant <em>Document Instance</em> that a
-          <em>Content Profile</em> be internally defined by use of a
-          <code>ttp:profile</code> element or internally referenced by a
-          <code>ttp:profile</code> attribute. More specifically, it is permitted that the
-          <em>Document Interchange Context</em> determines the applicable <em>Content
-          Profile</em> through private agreement, out-of-band protocol, or common use
-          (between sender and receiver) of a 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:profile</code> attribute be used when the
-          author wishes to reference one of the standard, predefined 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 <em>Profile Definition Document</em>.
-          However, it is not required that a conformant TTML Content processor 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 <em>Document Instance</em> 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 required (mandatory) that was either not specified in the underlying,
-          baseline profile or was specified as optional (voluntary) in the baseline
-          profile. A predefined profile is subsetted by specifying some feature or
-          extension to be optional (voluntary) that was specified as required 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>If a <em>Document Instance</em> makes use of a feature defined by <a href=
-        "#feature-designations"><b>D.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 feature</em> or a <em>used feature</em>
-        specification in one of its declared or referenced profiles. If a <em>Document
-        Instance</em> makes use of an extension designatable by <a href=
-        "#extension-designations"><b>E.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 extension</em> or a
-        <em>used extension</em> specification in one of its declared or referenced
-        profiles.</p>
-
-        <div class="note">
-          <p class="prefix"><b>Note:</b></p>
-
-          <p>A required or used feature specification is expressed directly (or
-          indirectly by referring to a profile) by means of a <a href=
-          "#parameter-vocabulary-feature"><code>ttp:feature</code></a> element where the
-          value of its <code>value</code> attribute is <code>required</code> or
-          <code>use</code>, respectively. A required or used extension specification is
-          expressed directly (or indirectly by referring to a profile) by means of a
-          <a href="#parameter-vocabulary-extension"><code>ttp:extension</code></a>
-          element where the value of its <code>value</code> attribute is
-          <code>required</code> or <code>use</code>, respectively.</p>
-        </div>
-
-        <p>An example of an author defined additive, derived profile of the DFXP
-        Presentation profile is shown below in <a href=
-        "#ttml-example-sub-profile"><b>Example Fragment – DFXP Additive
-        Profile</b></a>.</p><a id="ttml-example-sub-profile" name=
-        "ttml-example-sub-profile"></a>
-
-        <table class="example">
-          <caption>
-            Example Fragment – DFXP 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="dfxp-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 DFXP
-          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-dfxp-presentation"><b>F.2 DFXP 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="div2">
-        <h3><a id="vocabulary-overview" name="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" name="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="#parameters"><b>6 Parameters</b></a></p>
-            </li>
-
-            <li>
-              <p><a href="#content"><b>7 Content</b></a></p>
-            </li>
-
-            <li>
-              <p><a href="#styling"><b>8 Styling</b></a></p>
-            </li>
-
-            <li>
-              <p><a href="#layout"><b>9 Layout</b></a></p>
-            </li>
-
-            <li>
-              <p><a href="#timing"><b>10 Timing</b></a></p>
-            </li>
-
-            <li>
-              <p><a href="#animation"><b>11 Animation</b></a></p>
-            </li>
-
-            <li>
-              <p><a href="#metadata"><b>12 Metadata</b></a></p>
-            </li>
-          </ul>
-
-          <p>The core element vocabulary specified for use with a <em>Document
-          Instance</em> is enumerated in <a href="#element-vocab-table"><b>Table 3 –
-          Element Vocabulary</b></a>.</p><a id="element-vocab-table" name=
-          "element-vocab-table"></a>
-
-          <table class="common">
-            <caption>
-              Table 3 – Element Vocabulary
-            </caption>
-            <col width="25%" span="1">
-            <col span="1">
-
-            <tbody>
-              <tr>
-                <th>Module</th>
-
-                <th>Elements</th>
-              </tr>
-
-              <tr>
-                <td>Animation</td>
-
-                <td><a href="#animation-vocabulary-set">set</a></td>
-              </tr>
-
-              <tr>
-                <td>Content</td>
-
-                <td><a href="#document-structure-vocabulary-body">body</a>, <a href=
-                "#content-vocabulary-div">div</a>, <a href="#content-vocabulary-p">p</a>,
-                <a href="#content-vocabulary-span">span</a>, <a href=
-                "#content-vocabulary-br">br</a></td>
-              </tr>
-
-              <tr>
-                <td>Document</td>
-
-                <td><a href="#document-structure-vocabulary-tt">tt</a></td>
-              </tr>
-
-              <tr>
-                <td>Head</td>
-
-                <td><a href="#document-structure-vocabulary-head">head</a></td>
-              </tr>
-
-              <tr>
-                <td>Layout</td>
-
-                <td><a href="#layout-vocabulary-layout">layout</a>, <a href=
-                "#layout-vocabulary-region">region</a></td>
-              </tr>
-
-              <tr>
-                <td>Metadata</td>
-
-                <td><a href="#metadata-vocabulary-metadata">metadata</a></td>
-              </tr>
-
-              <tr>
-                <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-name">ttm:name</a>, <a href=
-                "#metadata-vocabulary-title">ttm:title</a></td>
-              </tr>
-
-              <tr>
-                <td>Parameter Items</td>
-
-                <td><a href="#parameter-vocabulary-profile">ttp:profile</a>, <a href=
-                "#parameter-vocabulary-features">ttp:features</a>, <a href=
-                "#parameter-vocabulary-feature">ttp:feature</a>, <a href=
-                "#parameter-vocabulary-extensions">ttp:extensions</a>, <a href=
-                "#parameter-vocabulary-extension">ttp:extension</a></td>
-              </tr>
-
-              <tr>
-                <td>Styling</td>
-
-                <td><a href="#styling-vocabulary-styling">styling</a>, <a href=
-                "#styling-vocabulary-style">style</a></td>
-              </tr>
-            </tbody>
-          </table>
-
-          <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 4
-          – Element Vocabulary Groups</b></a>.</p><a id="element-vocab-group-table" name=
-          "element-vocab-group-table"></a>
-
-          <table class="common">
-            <caption>
-              Table 4 – Element Vocabulary Groups
-            </caption>
-            <col width="25%" span="1">
-            <col span="1">
-
-            <tbody>
-              <tr>
-                <th>Group</th>
-
-                <th>Elements</th>
-              </tr>
-
-              <tr>
-                <td>Animation.class</td>
-
-                <td><a href="#animation-vocabulary-set">set</a></td>
-              </tr>
-
-              <tr>
-                <td>Block.class</td>
-
-                <td><a href="#content-vocabulary-div">div</a> | <a href=
-                "#content-vocabulary-p">p</a></td>
-              </tr>
-
-              <tr>
-                <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>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-title">ttm:title</a></td>
-              </tr>
-
-              <tr>
-                <td>Parameters.class</td>
-
-                <td><a href="#parameter-vocabulary-profile">ttp:profile</a></td>
-              </tr>
-            </tbody>
-          </table>
-
-          <p>The attribute vocabulary specified for use with the core vocabulary catalog
-          is enumerated in <a href="#attribute-vocab-table"><b>Table 5 – Attribute
-          Vocabulary</b></a>.</p><a id="attribute-vocab-table" name=
-          "attribute-vocab-table"></a>
-
-          <table class="common">
-            <caption>
-              Table 5 – Attribute Vocabulary
-            </caption>
-            <col width="25%" span="1">
-            <col span="1">
-
-            <tbody>
-              <tr>
-                <th>Module</th>
-
-                <th>Attributes</th>
-              </tr>
-
-              <tr>
-                <td>Core Attributes</td>
-
-                <td><a href="#content-attribute-id">xml:id</a>, <a href=
-                "#content-attribute-lang">xml:lang</a>, <a href=
-                "#content-attribute-space">xml:space</a></td>
-              </tr>
-
-              <tr>
-                <td>Layout</td>
-
-                <td><a href="#layout-attribute-region">region</a></td>
-              </tr>
-
-              <tr>
-                <td>Metadata Attributes</td>
-
-                <td><a href="#metadata-attribute-agent">ttm:agent</a>, <a href=
-                "#metadata-attribute-role">ttm:role</a></td>
-              </tr>
-
-              <tr>
-                <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-pixelAspectRatio">ttp:pixelAspectRatio</a>,
-                <a href="#parameter-attribute-profile">ttp:profile</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>
-                <td>Styling</td>
-
-                <td><a href="#style-attribute-style">style</a></td>
-              </tr>
-
-              <tr>
-                <td>Styling Attributes</td>
-
-                <td><a href="#style-attribute-backgroundColor">tts:backgroundColor</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-fontSize">tts:fontSize</a>, <a href=
-                "#style-attribute-fontStyle">tts:fontStyle</a>, <a href=
-                "#style-attribute-fontWeight">tts:fontWeight</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-showBackground">tts:showBackground</a>, <a href=
-                "#style-attribute-textAlign">tts:textAlign</a>, <a href=
-                "#style-attribute-textDecoration">tts:textDecoration</a>, <a href=
-                "#style-attribute-textOutline">tts:textOutline</a>, <a href=
-                "#style-attribute-unicodeBidi">tts:unicodeBidi</a>, <a href=
-                "#style-attribute-visibility">tts:visibility</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>
-                <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 – 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" name=
-          "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 <em>Document
-          Instance</em> may contain arbitrary namespace qualified elements that reside in
-          any namespace other than those namespaces defined for use with this
-          specification. Furthermore, a conforming <em>Document Instance</em> 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="parameters" name="parameters"></a>6 Parameters</h2>
-
-      <p>This section specifies the <em>parameters</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 <em>Document Processing Context</em> by means of which TTML Content
-      can be related to an external environment.</p>
-
-      <div class="div2">
-        <h3><a id="parameter-element-vocabulary" name=
-        "parameter-element-vocabulary"></a>6.1 Parameter Element Vocabulary</h3>
-
-        <p>The following elements, all defined in the TT Parameter Namespace, specify
-        parametric information that applies to a <em>Document Instance</em> or
-        <em>Content Processor</em>:</p>
-
-        <ul>
-          <li>
-            <p><a href="#parameter-vocabulary-profile"><b>6.1.1 ttp:profile</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-vocabulary-features"><b>6.1.2 ttp:features</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-vocabulary-feature"><b>6.1.3 ttp:feature</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-vocabulary-extensions"><b>6.1.4
-            ttp:extensions</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-vocabulary-extension"><b>6.1.5
-            ttp:extension</b></a></p>
-          </li>
-        </ul>
-
-        <div class="div3">
-          <h4><a id="parameter-vocabulary-profile" name=
-          "parameter-vocabulary-profile"></a>6.1.1 ttp:profile</h4>
-
-          <p>The <code>ttp:profile</code> element is used to specify a collection of used
-          (mandatory and enabled), required (mandatory), and optional (voluntary)
-          features and extensions that must or may be supported by a <em>Content
-          Processor</em> in order to process a <em>Document Instance</em> that makes (or
-          may make) use of such features and extensions.</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>D 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 uses of the <code>ttp:profile</code>
-          element:</p>
-
-          <ul>
-            <li>
-              <p>as a child of the <code>head</code> element within a TTML <em>Document
-              Instance</em>;</p>
-            </li>
-
-            <li>
-              <p>as the root element of a TTML <em>Profile Definition Document</em>
-              instance;</p>
-            </li>
-          </ul>
-
-          <p>When a <code>tt:profile</code> element appears within a TTML <em>Document
-          Instance</em>, its purpose is to express authorial intentions about which
-          features and extensions must or may be supported by a recipient content
-          processor. In addition, the element indirectly expresses information about the
-          set of features or extensions that are (or may expected to be) used by the
-          <em>Document Instance</em>.</p>
-
-          <p>When a <code>tt:profile</code> element is used by a TTML <em>Profile
-          Definition Document</em> instance, it serves to publish a machine readable
-          specification of a specific TTML Content profile, of which this specification
-          defines three such <em>Profile Definition Documents</em> in <a href=
-          "#profiles"><b>F Profiles</b></a>.</p>
-
-          <p>The <code>ttp:profile</code> element accepts as its children zero or more
-          elements in the <code>Metadata.class</code> element group, followed by zero or
-          more <code>ttp:features</code> elements, followed by zero or more
-          <code>ttp:extensions</code> elements.</p><a id="elt-syntax-parameter-profile"
-          name="elt-syntax-parameter-profile"></a>
-
-          <table class="syntax">
-            <caption>
-              XML Representation – Element Information Item: ttp:profile
-            </caption>
-
-            <tbody>
-              <tr>
-                <td>
-                  <div class="exampleInner">
-                    <pre>
-&lt;ttp:profile
-  use = string
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#parameter-vocabulary-features">ttp:features</a>*, <a href=
-"#parameter-vocabulary-extensions">ttp:extensions</a>*
-&lt;/ttp:profile&gt;
-</pre>
-                  </div>
-                </td>
-              </tr>
-            </tbody>
-          </table>
-
-          <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-profiles"><b>5.2 Profiles</b></a>. In this
-          case, the profile designator must refer to (1) a standard, predefined
-          <em>Profile Definition Document</em> as defined by <a href="#profiles"><b>F
-          Profiles</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 baseline profile of the specifying
-          <code>ttp:profile</code> element.</p>
-
-          <p>If the <code>use</code> attribute is not specified, then the baseline
-          profile 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 collection of features and extensions of a profile are determined
-          according to the following ordered rules:</p>
-
-          <ol class="enumar">
-            <li>
-              <p>initialize the features and extensions of the profile to the empty
-              set;</p>
-            </li>
-
-            <li>
-              <p>if a <code>use</code> attribute is present, then augment the profile
-              with the set of features and extensions specified by the referenced
-              baseline profile;</p>
-            </li>
-
-            <li>
-              <p>for each <code>ttp:feature</code> and <code>ttp:extension</code> element
-              descendant of the <code>ttp:profile</code> element, using a post-order
-              traversal, merge the specified feature or extension with the features and
-              extensions of the profile, where merging a feature or extension entails
-              replacing an existing feature or extension specification, if it already
-              exists, or adding a new feature or extension specification, if it does not
-              yet exist in the profile;</p>
-            </li>
-          </ol>
-
-          <p>A conformant TTML processor is not required to be able to dereference a
-          <em>Profile Definition Document</em> that is not one of the standard,
-          predefined profiles defined by <a href="#profiles"><b>F 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 <em>Profile
-          Definition Document</em>, 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 <em>Document
-          Instance</em> due to the inability to reference a non-standard <em>Profile
-          Definition Document</em>, 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="parameter-vocabulary-profile-example-1" name=
-          "parameter-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="dfxp-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 DFXP 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="parameter-vocabulary-features" name=
-          "parameter-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 requirements.</p>
-
-          <p>The <code>ttp:features</code> element accepts as its children zero or more
-          elements in the <code>Metadata.class</code> element group, followed by zero or
-          more <code>ttp:feature</code> elements.</p><a id=
-          "elt-syntax-parameter-features" name="elt-syntax-parameter-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 = string : <em>TT Feature Namespace</em>
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#parameter-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>D.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="parameter-vocabulary-feature" name=
-          "parameter-vocabulary-feature"></a>6.1.3 ttp:feature</h4>
-
-          <p>The <code>ttp:feature</code> element is used to specify infomation about
-          support requirements for a particular feature.</p>
-
-          <p>The children of the <code>ttp:feature</code> element must express a
-          non-empty sequence of character information items that adheres to the
-          <code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part
-          2]</a>, §3.2.17.</p><a id="elt-syntax-parameter-feature" name=
-          "elt-syntax-parameter-feature"></a>
-
-          <table class="syntax">
-            <caption>
-              XML Representation – Element Information Item: ttp:feature
-            </caption>
-
-            <tbody>
-              <tr>
-                <td>
-                  <div class="exampleInner">
-                    <pre>
-&lt;ttp:feature
-  value = (optional|required|use) : required
-  <a href="#content-attribute-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>If the URI expressed by the content of the <code>ttp:feature</code> element
-          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>D.1
-          Feature Designations</b></a>.</p>
-
-          <p>If the URI expressed by the content of the <code>ttp:feature</code> element
-          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 whether a conforming TTML
-          processor must or may implement the designated feature in order to process the
-          document. If the value of the <code>value</code> attribute is
-          <code>optional</code>, then the processor need not implement or otherwise
-          support the feature in order to process the document; if the value is
-          <code>required</code>, then the processor must implement or otherwise support
-          the feature, irrespective of whether the feature is enabled or disabled, in
-          order to process the document; if the value is <code>use</code>, then the
-          processor must both (1) implement or otherwise support the feature and (2) have
-          enabled (activated) use of the feature.</p>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>The default value of the <code>value</code> attribute is
-            <code>required</code>, as indicated in the above element information item
-            definition. Therefore, if a <code>value</code> attribute is not specified on
-            a <code>ttp:feature</code> element, it is equivalent to specifying that
-            support for the feature is required.</p>
-          </div>
-
-          <p>If the value of the <code>value</code> attribute is <code>required</code> or
-          <code>use</code> and the TTML processor implementation does not support the
-          feature, or if the <code>value</code> attribute is <code>use</code> and the
-          TTML processor implementation supports but has disabled that feature, 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 <em>Document Instance</em> due to the
-          specification of a required, but unsupported feature by this element, 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>If the value of the <code>value</code> attribute is <code>optional</code>,
-          and if the TTML processor implementation does not support the feature, then it
-          may further process the document even in the case that some use of the feature
-          is present in the document. In the case of actual use of a feature designated
-          as optional, the default semantics associated with that feature apply; that is,
-          the processor may behave as if the feature were not actually used or referenced
-          by the document. Notwithstanding the above, the syntactic presence or reference
-          to an optional feature by a document must not be considered to be a violation
-          of document validity or a barrier to further processing if the syntactic
-          expression is well-formed and valid.</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 given profile, then it
-          must be interpreted as if the feature were specified with the
-          <code>value</code> attribute equal to <code>optional</code>.</p>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>In particular, if some feature is not present in a profile definition,
-            then it is not to be interpreted as meaning the use of that feature (in a
-            <em>Document Instance</em>) is disallowed or otherwise prohibited.</p>
-          </div>
-
-          <p>The <code>ttp:feature</code> element is illustrated by the following
-          example.</p><a id="parameter-vocabulary-feature-example-1" name=
-          "parameter-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/dfxp-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>
-  &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 DFXP presentation profile is used as the
-            baseline profile. This baseline profile is then modified by two
-            <code>ttp:feature</code> elements in order to superset the baseline profile
-            (since neither <code>#fontStyle-italic</code> nor
-            <code>#textDecoration-under</code> are required by the DFXP presentation
-            profile).</p>
-
-            <p>The effect of this example is to express authorial intentions that italic
-            font style and text underlining must be supported.</p>
-          </div>
-        </div>
-
-        <div class="div3">
-          <h4><a id="parameter-vocabulary-extensions" name=
-          "parameter-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 requirements.</p>
-
-          <p>The <code>ttp:extensions</code> element accepts as its children zero or more
-          elements in the <code>Metadata.class</code> element group, followed by zero or
-          more <code>ttp:extension</code> elements.</p><a id=
-          "elt-syntax-parameter-extensions" name="elt-syntax-parameter-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 = string : <em>TT Extension Namespace</em>
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#parameter-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>E.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="parameter-vocabulary-extension" name=
-          "parameter-vocabulary-extension"></a>6.1.5 ttp:extension</h4>
-
-          <p>The <code>ttp:extension</code> element is used to specify infomation about
-          support requirements for a particular extension.</p>
-
-          <p>The children of the <code>ttp:extension</code> element must express a
-          non-empty sequence of character information items that adheres to the
-          <code>xsd:anyURI</code> data type defined by <a href="#xsd-2">[XML Schema Part
-          2]</a>, §3.2.17.</p><a id="elt-syntax-parameter-extension" name=
-          "elt-syntax-parameter-extension"></a>
-
-          <table class="syntax">
-            <caption>
-              XML Representation – Element Information Item: ttp:extension
-            </caption>
-
-            <tbody>
-              <tr>
-                <td>
-                  <div class="exampleInner">
-                    <pre>
-&lt;ttp:extension
-  value = (optional|required|use) : required
-  <a href="#content-attribute-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>If the URI expressed by the content of the <code>ttp:extension</code>
-          element 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>E.1
-          Extension Designations</b></a>.</p>
-
-          <p>If the URI expressed by the content of the <code>ttp:feature</code> element
-          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 whether a conforming TTML
-          processor must or may implement the designated extension in order to process
-          the document. If the value of the <code>value</code> attribute is
-          <code>optional</code>, then the processor need not implement or otherwise
-          support the extension in order to process the document; if the value is
-          <code>required</code>, then the processor must implement or otherwise support
-          the extension in order to process the document; if the value is
-          <code>use</code>, then the processor must both (1) implement or otherwise
-          support the extension and (2) enable (activate) use of the extension.</p>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>The default value of the <code>value</code> attribute is
-            <code>required</code>, as indicated in the above element information item
-            definition. Therefore, if a <code>value</code> attribute is not specified on
-            a <code>ttp:extension</code> element, it is equivalent to specifying that
-            support for the extension is required.</p>
-          </div>
-
-          <p>If the value of the <code>value</code> attribute is <code>required</code> or
-          <code>use</code> and the TTML processor implementation does not support the
-          extension, or if the <code>value</code> attribute is <code>use</code> and the
-          TTML processor implementation supports but has disabled that extension, 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 <em>Document Instance</em> due to the
-          specification of a required, but unsupported extension by this element, 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>If the value of the <code>value</code> attribute is <code>optional</code>,
-          and if the TTML processor implementation does not support the extension, then
-          it may further process the document even in the case that some use of the
-          extension is present in the document. In the case of actual use of an extension
-          designated as optional, the default semantics associated with that extension
-          apply; that is, the processor may behave as if the extension were not actually
-          used or referenced by the document. Notwithstanding the above, the syntactic
-          presence or reference to an optional extension by a document must not be
-          considered to be a violation of document validity or a barrier to further
-          processing if the syntactic expression is well-formed and valid.</p>
-
-          <p>If some well known extension is not specified by a
-          <code>ttp:extension</code> element in a given profile, then it must be
-          interpreted as if the extension were specified with the <code>value</code>
-          attribute equal to <code>optional</code>.</p>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>In particular, if some extension is not present in a profile definition,
-            then it is not to be interpreted as meaning the use of that extension (in a
-            <em>Document Instance</em>) is disallowed or otherwise prohibited.</p>
-          </div>
-
-          <p>The <code>ttp:extension</code> element is illustrated by the following
-          example.</p><a id="parameter-vocabulary-extension-example-1" name=
-          "parameter-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/dfxp-transformation"&gt;
-  &lt;ttp:extensions xml:base="http://example.org/ttaf1/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 DFXP 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 DFXP 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="parameter-attribute-vocabulary" name=
-        "parameter-attribute-vocabulary"></a>6.2 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>6.2.1
-            ttp:cellResolution</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-clockMode"><b>6.2.2
-            ttp:clockMode</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-dropMode"><b>6.2.3 ttp:dropMode</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-frameRate"><b>6.2.4
-            ttp:frameRate</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-frameRateMultiplier"><b>6.2.5
-            ttp:frameRateMultiplier</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-markerMode"><b>6.2.6
-            ttp:markerMode</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-pixelAspectRatio"><b>6.2.7
-            ttp:pixelAspectRatio</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-profile"><b>6.2.8 ttp:profile</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-subFrameRate"><b>6.2.9
-            ttp:subFrameRate</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-tickRate"><b>6.2.10 ttp:tickRate</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#parameter-attribute-timeBase"><b>6.2.11 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" name=
-          "parameter-attribute-cellResolution"></a>6.2.1 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 root
-          container region 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" name=
-          "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="#cea608c">[CEA-608-C]</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>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>Except where indicated otherwise, when a <a href=
-            "#style-value-length">&lt;length&gt;</a> expressed in cells expresses a
-            dimension parallel to the inline or block progression dimension, the cell's
-            dimension in the inline or block progression dimension applies, respectively.
-            For example, if padding (on all four edges) is specified as 0.1c, the cell
-            resolution is 20 by 10, and the root container extent 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" name=
-          "parameter-attribute-clockMode"></a>6.2.2 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>6.2.11 ttp:timeBase</b></a>.</p>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>See <a href="#timing-time-value-expressions"><b>10.3 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" name=
-          "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>6.2.11 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" name=
-          "parameter-attribute-dropMode"></a>6.2.3 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>6.2.11 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" name=
-          "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>6.2.11 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" name=
-          "parameter-attribute-frameRate"></a>6.2.4 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 <em>Document
-          Instance</em> 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-frameRate-syntax" name=
-          "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 <em>Document Instance</em> is used to
-          interpret time expressions that are expressed in <em>frames</em> as defined by
-          <a href="#timing-value-timeExpression"><b>10.3.1
-          &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>N.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" name=
-          "parameter-attribute-frameRateMultiplier"></a>6.2.5
-          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" name=
-          "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" name=
-          "parameter-attribute-markerMode"></a>6.2.6 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>6.2.11 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" name=
-          "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>6.2.11 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 indicates this choice was incorrect, and that the most
-            common default is <code>discontinuous</code>.</p>
-          </div>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>Due to lack of industry consensus on the utility and interpretation of the
-            <code>continuous</code> marker mode, authors are advised to avoid its use.
-            Furthermore, the <code>ttp:markerMode</code> is being considered for
-            deprecation in the next revision of this specification.</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 <em>Content Processor</em> must create and maintain a
-          <em>Synthetic SMPTE Document Syncbase</em> within which these time expressions
-          are interpreted as further described in <a href=
-          "#timing-time-intervals"><b>10.4 Time Intervals</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 <em>Synthetic SMPTE Document Syncbase</em>, 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 <em>SMPTE Time Code</em> synchronization events
-            (markers), where the <em>Document Processing Context</em> 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
-          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 <em>Document Processing
-            Context</em> 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-pixelAspectRatio" name=
-          "parameter-attribute-pixelAspectRatio"></a>6.2.7 ttp:pixelAspectRatio</h4>
-
-          <p>The <code>ttp:pixelAspectRatio</code> attribute may be used by a content
-          author to express the aspect ratio of non-square pixels in the production of
-          content that makes use of pixel coordinates.</p>
-
-          <p>If specified, the value of this attribute must adhere to the following
-          syntax:</p><a id="parameter-attribute-pixelAspectRatio-syntax" name=
-          "parameter-attribute-pixelAspectRatio-syntax"></a>
-
-          <table class="syntax">
-            <caption>
-              Syntax Representation – ttp:pixelAspectRatio
-            </caption>
-
-            <tbody>
-              <tr>
-                <td>
-                  <div class="exampleInner">
-                    <pre>
-ttp:pixelAspectRatio
-  : width height                            // <em>width</em> != 0; <em>height</em> != 0
-
-width | height
-  : <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 width and height 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 class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>This parameter may be used by a content transcoder or translator in order
-            to convert pixel measurements between different pixel aspect ratios while
-            still maintaining authorial layout intentions.</p>
-          </div>
-        </div>
-
-        <div class="div3">
-          <h4><a id="parameter-attribute-profile" name=
-          "parameter-attribute-profile"></a>6.2.8 ttp:profile</h4>
-
-          <p>The <code>ttp:profile</code> attribute may be used by a content author to
-          express the profile of the Timed Text Markup Language (TTML) used in a
-          <em>Document Instance</em>.</p>
-
-          <p>If specified, the value of this 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, further, must specify a profile designator in accordance
-          with <a href="#vocabulary-profiles"><b>5.2 Profiles</b></a>.</p>
-
-          <p>A <code>ttp:profile</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" name=
-          "parameter-attribute-subFrameRate"></a>6.2.9 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
-          <em>Document Instance</em> 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" name=
-          "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 <em>Document Instance</em> is used to
-          interpret time expressions that are expressed in <em>sub-frames</em> as defined
-          by <a href="#timing-value-timeExpression"><b>10.3.1
-          &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>N.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" name=
-          "parameter-attribute-tickRate"></a>6.2.10 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 <em>Document
-          Instance</em> 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" name=
-          "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 <em>Document Instance</em> 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>10.3.1 &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>N.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" name=
-          "parameter-attribute-timeBase"></a>6.2.11 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
-          <em>Document Instance</em>.</p>
-
-          <p>If specified, the value of this attribute must adhere to the following
-          syntax:</p><a id="parameter-attribute-timeBase-syntax" name=
-          "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 <em>Document
-          Instance</em> is to be synchronized, or it may be the content of a <em>Document
-          Instance</em> 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 <em>Document Instance</em> 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>6.2.6 ttp:markerMode</b></a> and <a href=
-          "#parameter-attribute-dropMode"><b>6.2.3 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=
-            "#smil21">[SMIL 2.1]</a>, § 10.4.1, 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 <em>Document Instance</em> 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
-            <em>Document Instance</em>, the interpretation of time expressions is uniform
-            throughout the <em>Document Instance</em>.</p>
-          </div>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>See <a href="#time-expression-semantics"><b>N 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" name="content"></a>7 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" name="content-element-vocabulary"></a>7.1
-        Content Element Vocabulary</h3>
-
-        <p>The following elements specify the structure and principal content aspects of
-        a <em>Document Instance</em>:</p>
-
-        <ul>
-          <li>
-            <p><a href="#document-structure-vocabulary-tt"><b>7.1.1 tt</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#document-structure-vocabulary-head"><b>7.1.2 head</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#document-structure-vocabulary-body"><b>7.1.3 body</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#content-vocabulary-div"><b>7.1.4 div</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#content-vocabulary-p"><b>7.1.5 p</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#content-vocabulary-span"><b>7.1.6 span</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#content-vocabulary-br"><b>7.1.7 br</b></a></p>
-          </li>
-        </ul>
-
-        <div class="div3">
-          <h4><a id="document-structure-vocabulary-tt" name=
-          "document-structure-vocabulary-tt"></a>7.1.1 tt</h4>
-
-          <p>The <code>tt</code> element serves as the root document element of a
-          <em>Document Instance</em>.</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" name="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="#style-attribute-extent">tts:extent</a> = string
-  <a href="#content-attribute-id">xml:id</a> = ID
-  <a href="#content-attribute-lang"><span class="reqattr">xml:lang</span></a> = string
-  <a href=
-"#content-attribute-space">xml:space</a> = (<em>default</em>|<em>preserve</em>) : default
-  {<em>any attribute in TT Parameter 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 <em>Root Temporal Extent</em>, i.e., the time interval over which a
-          <em>Document Instance</em> 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 <code>tts:extent</code> attribute is specified on the <code>tt</code>
-          element, then it must adhere to <a href="#style-attribute-extent"><b>8.2.7
-          tts:extent</b></a>, in which case it specifies the spatial extent of the
-          <em>Root Container Region</em> in which content regions are located and
-          presented. If no <code>tts:extent</code> attribute is specified, then the
-          spatial extent of the <em>Root Container Region</em> is considered to be
-          determined by the <em>Document Processing Context</em>. The origin of the
-          <em>Root Container Region</em> is determined by the <em>Document Processing
-          Context</em>.</p>
-
-          <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
-            <em>Root Container Region</em> 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=
-            "#cea708d">[CEA-708-D]</a> , §4.5 “Caption Service Metadata”, “ASPECT
-            RATIO”.</p>
-          </div>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>In the absence of other requirements, and if a <em>Related Media
-            Object</em> exists, then it is recommended that the origin of the <em>Root
-            Container Region</em> be established so that it is centered in the region
-            within which the <em>Related Media Object</em> is presented.</p>
-          </div>
-
-          <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 <em>Document
-          Instance</em>.</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" name=
-          "document-structure-vocabulary-head"></a>7.1.2 head</h4>
-
-          <p>The <code>head</code> element is a container element used to group header
-          matter, including metadata, profile, styling, and layout information.</p>
-
-          <p>The <code>head</code> element accepts as its children zero or more elements
-          in the <code>Metadata.class</code> element group, followed by zero or more
-          elements in the <code>Parameters.class</code> element group, followed by zero
-          or one <code>styling</code> element, followed by zero or one
-          <code>layout</code> element.</p>
-
-          <p>Any metadata specified by children in the <code>Metadata.class</code>
-          element group applies semantically to the <em>Document Instance</em> 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 <em>Document Instance</em> as a
-          whole, and not just the <code>head</code> element.</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
-          content elements.</p>
-
-          <p>A <code>layout</code> child element is used to specify layout constructs
-          that are referenced by content elements.</p><a id="elt-syntax-head" name=
-          "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-id">xml:id</a> = ID
-  <a href="#content-attribute-lang">xml:lang</a> = string
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#element-vocab-group-table">Parameters.class</a>*, <a href=
-"#styling-vocabulary-styling">styling</a>?, <a href=
-"#layout-vocabulary-layout">layout</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 <em>Root Temporal Extent</em>.</p>
-        </div>
-
-        <div class="div3">
-          <h4><a id="document-structure-vocabulary-body" name=
-          "document-structure-vocabulary-body"></a>7.1.3 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 <code>Metadata.class</code> element group, followed by zero or more
-          elements in the <code>Animation.class</code> element group, followed by zero or
-          more <code>div</code> elements.</p>
-
-          <p>Any metadata specified by children in the <code>Metadata.class</code>
-          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
-          <code>Animation.class</code> element group apply semantically to the
-          <code>body</code> element.</p><a id="elt-syntax-body" name=
-          "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="#timing-attribute-begin">begin</a> = <a href=
-"#timing-value-timeExpression">&lt;timeExpression&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-id">xml:id</a> = ID
-  <a href="#content-attribute-lang">xml:lang</a> = string
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#element-vocab-group-table">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 <em>Root Temporal
-          Extent</em>. Similarly, if the end point of this interval remains unspecified,
-          then the end point is interpreted as the ending point of the <em>Root Temporal
-          Extent</em>.</p>
-
-          <div class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>A <em>Document Instance</em> 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 <em>Root Temporal Extent</em>.</p>
-
-          <p>If the <em>Root Temporal Extent</em> 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 <em>Root
-          Temporal Extent</em>.</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
-            <em>Document Instance</em> are available for style inheritance by descendant
-            content elements 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" name="content-vocabulary-div"></a>7.1.4
-          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 <code>Metadata.class</code> element group, followed by zero or more
-          elements in the <code>Animation.class</code> element group, followed by zero or
-          more <code>div</code> or <code>p</code> elements.</p>
-
-          <p>Any metadata specified by children in the <code>Metadata.class</code>
-          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
-          <code>Animation.class</code> element group apply semantically to the
-          <code>div</code> element.</p><a id="elt-syntax-div" name="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="#timing-attribute-begin">begin</a> = <a href=
-"#timing-value-timeExpression">&lt;timeExpression&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-id">xml:id</a> = ID
-  <a href="#content-attribute-lang">xml:lang</a> = string
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#element-vocab-group-table">Animation.class</a>*, <a href=
-"#element-vocab-group-table">Block.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
-            <em>Document Instance</em> are available for style inheritance by descendant
-            content elements 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>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" name="content-vocabulary-p"></a>7.1.5 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 <code>Metadata.class</code> element group, followed by zero or more
-          elements in the <code>Animation.class</code> element group, followed by zero or
-          more intermixed <code>span</code> elements, <code>br</code> elements, or text
-          nodes interpreted as an anonymous spans.</p>
-
-          <p>Any metadata specified by children in the <code>Metadata.class</code>
-          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
-          <code>Animation.class</code> element group apply semantically to the
-          <code>p</code> element.</p><a id="elt-syntax-p" name="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="#timing-attribute-begin">begin</a> = <a href=
-"#timing-value-timeExpression">&lt;timeExpression&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-id">xml:id</a> = ID
-  <a href="#content-attribute-lang">xml:lang</a> = string
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#element-vocab-group-table">Animation.class</a>*, <a href=
-"#element-vocab-group-table">Inline.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
-            <em>Document Instance</em> are available for style inheritance by descendant
-            content elements such as <code>span</code> and <code>br</code>.</p>
-          </div>
-
-          <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
-          character information items, 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>9.3.3 Synchronic Flow Processing</b></a>
-            for further details.</p>
-          </div>
-        </div>
-
-        <div class="div3">
-          <h4><a id="content-vocabulary-span" name="content-vocabulary-span"></a>7.1.6
-          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 <code>Metadata.class</code> element group, followed by zero or more
-          elements in the <code>Animation.class</code> element group, followed by zero or
-          more intermixed <code>span</code> elements, <code>br</code> elements, or text
-          nodes interpreted as anonymous spans.</p>
-
-          <p>Any metadata specified by children in the <code>Metadata.class</code>
-          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
-          <code>Animation.class</code> element group apply semantically to the
-          <code>span</code> element.</p><a id="elt-syntax-span" name=
-          "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="#timing-attribute-begin">begin</a> = <a href=
-"#timing-value-timeExpression">&lt;timeExpression&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-id">xml:id</a> = ID
-  <a href="#content-attribute-lang">xml:lang</a> = string
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#element-vocab-group-table">Animation.class</a>*, <a href=
-"#element-vocab-group-table">Inline.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
-            <em>Document Instance</em> are available for style inheritance by descendant
-            content elements 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>
-        </div>
-
-        <div class="div3">
-          <h4><a id="content-vocabulary-br" name="content-vocabulary-br"></a>7.1.7
-          br</h4>
-
-          <p>The <code>br</code> element denotes an explicit line break.</p><a id=
-          "elt-syntax-br" name="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="#style-attribute-style">style</a> = IDREFS
-  <a href="#content-attribute-id">xml:id</a> = ID
-  <a href="#content-attribute-lang">xml:lang</a> = string
-  <a href="#content-attribute-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-table">Metadata.class</a>*, <a href=
-"#element-vocab-group-table">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>
-        </div>
-      </div>
-
-      <div class="div2">
-        <h3><a id="content-attribute-vocabulary" name=
-        "content-attribute-vocabulary"></a>7.2 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-id"><b>7.2.1 xml:id</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#content-attribute-lang"><b>7.2.2 xml:lang</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#content-attribute-space"><b>7.2.3 xml:space</b></a></p>
-          </li>
-        </ul>
-
-        <div class="div3">
-          <h4><a id="content-attribute-id" name="content-attribute-id"></a>7.2.1
-          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-lang" name="content-attribute-lang"></a>7.2.2
-          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.</p>
-        </div>
-
-        <div class="div3">
-          <h4><a id="content-attribute-space" name="content-attribute-space"></a>7.2.3
-          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.</p>
-
-          <p>The semantics of the value <code>default</code> are fixed to mean that when
-          performing presentation processing of a <em>Document Instance</em> as described
-          by <a href="#semantics-region-layout-step-2"><b>9.3.3 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>
-      </div>
-    </div>
-
-    <div class="div1">
-      <h2><a id="styling" name="styling"></a>8 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 <em>Document Instances</em> in
-      any particular way; but an implementation of this model by a TTML Presentation
-      Processor 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 intended effect of the attributes in this
-      section are to be compatible with the layout model of XSL. Presentation agents may
-      however 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" name="styling-element-vocabulary"></a>8.1
-        Styling Element Vocabulary</h3>
-
-        <p>The following elements specify the structure and principal styling aspects of
-        a <em>Document Instance</em>:</p>
-
-        <ul>
-          <li>
-            <p><a href="#styling-vocabulary-styling"><b>8.1.1 styling</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#styling-vocabulary-style"><b>8.1.2 style</b></a></p>
-          </li>
-        </ul>
-
-        <div class="div3">
-          <h4><a id="styling-vocabulary-styling" name=
-          "styling-vocabulary-styling"></a>8.1.1 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 <code>Metadata.class</code> element group, followed by zero or
-          more <code>style</code> elements.</p><a id="elt-syntax-styling" name=
-          "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-id">xml:id</a> = ID
-  <a href="#content-attribute-lang">xml:lang</a> = string
-  <a href="#content-attribute-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-table">Metadata.class</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 <em>Root Temporal Extent</em>.</p>
-        </div>
-
-        <div class="div3">
-          <h4><a id="styling-vocabulary-style" name="styling-vocabulary-style"></a>8.1.2
-          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>8.4.4.2 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" name=
-          "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="#style-attribute-style">style</a> = IDREFS
-  <a href="#content-attribute-id">xml:id</a> = ID
-  <a href="#content-attribute-lang">xml:lang</a> = string
-  <a href="#content-attribute-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> EMPTY
-&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>8.4.1.2 Referential
-          Styling</b></a> and <a href=
-          "#semantics-style-association-chained-referential"><b>8.4.1.3 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 class="note">
-            <p class="prefix"><b>Note:</b></p>
-
-            <p>In this version of this specification, the <code>style</code> element is
-            the only non-metadata element that is not defined to accept
-            <code>Metadata.class</code> children. It is expected that this asymmetry will
-            be corrected in the next revision of this specification.</p>
-          </div>
-        </div>
-      </div>
-
-      <div class="div2">
-        <h3><a id="styling-attribute-vocabulary" name=
-        "styling-attribute-vocabulary"></a>8.2 Styling Attribute Vocabulary</h3>
-
-        <p>This section defines the <a href="#style-attribute-style"><b>8.2.1
-        style</b></a> attribute used with both style definition elements as well as
-        content 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
-        content elements that support inline style specifications:</p>
-
-        <ul>
-          <li>
-            <p><a href="#style-attribute-backgroundColor"><b>8.2.2
-            tts:backgroundColor</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-color"><b>8.2.3 tts:color</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-direction"><b>8.2.4 tts:direction</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-display"><b>8.2.5 tts:display</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-displayAlign"><b>8.2.6
-            tts:displayAlign</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-extent"><b>8.2.7 tts:extent</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-fontFamily"><b>8.2.8 tts:fontFamily</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-fontSize"><b>8.2.9 tts:fontSize</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-fontStyle"><b>8.2.10 tts:fontStyle</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-fontWeight"><b>8.2.11 tts:fontWeight</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-lineHeight"><b>8.2.12 tts:lineHeight</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-opacity"><b>8.2.13 tts:opacity</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-origin"><b>8.2.14 tts:origin</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-overflow"><b>8.2.15 tts:overflow</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-padding"><b>8.2.16 tts:padding</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-showBackground"><b>8.2.17
-            tts:showBackground</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-textAlign"><b>8.2.18 tts:textAlign</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-textDecoration"><b>8.2.19
-            tts:textDecoration</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-textOutline"><b>8.2.20
-            tts:textOutline</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-unicodeBidi"><b>8.2.21
-            tts:unicodeBidi</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-visibility"><b>8.2.22 tts:visibility</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-wrapOption"><b>8.2.23 tts:wrapOption</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-writingMode"><b>8.2.24
-            tts:writingMode</b></a></p>
-          </li>
-
-          <li>
-            <p><a href="#style-attribute-zIndex"><b>8.2.25 tts:zIndex</b></a></p>
-          </li>
-        </ul>
-
-        <p>Unless explicitly stated otherwise, linear white-space (LWSP) must appear
-        between adjacent non-terminal components of a value of a TT Style or TT Style
-        Extension 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>A style property may be expressed as a specified attribute on any content
-          element 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="div3">
-          <h4><a id="style-attribute-style" name="style-attribute-style"></a>8.2.1
-          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
-          specified style 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="#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>
-
-            <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.</p>
-
-          <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>8.4.1.2 Referential
-            Styling</b></a> and <a href=
-            "#semantics-style-association-chained-referential"><b>8.4.1.3 Chained
-            Referential Styling</b></a>, for further information on its semantics.</p>
-          </div>
-        </div>
-
-        <div class="div3">
-          <h4><a id="style-attribute-backgroundColor" name=
-          "style-attribute-backgroundColor"></a>8.2.2 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>
-
-          <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" name=
-          "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</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" name=
-          "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><a id="style-attribute-backgroundColor-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-color" name="style-attribute-color"></a>8.2.3
-          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" name=
-          "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</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 presentation processor should use an initial value that is highly
-          contrastive to the background color of the root container region.</p>
-
-          <p>The <code>tts:color</code> style is illustrated by the following
-          example.</p><a id="style-attribute-color-example-1" name=
-          "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><a id="style-attribute-color-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-direction" name=
-          "style-attribute-direction"></a>8.2.4 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" name=
-          "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 specified value of this attribute is not supported, then a presentation
-          processor must ignore the attribute.</p>
-
-          <p>The <code>tts:direction</code> style is illustrated by the following
-          example.</p><a id="style-attribute-direction-example-1" name=
-          "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><a id="style-attribute-direction-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-display" name="style-attribute-display"></a>8.2.5
-          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" name=
-          "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" name=
-          "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><a id="style-attribute-display-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-displayAlign" name=
-          "style-attribute-displayAlign"></a>8.2.6 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>
-
-          <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" name=
-          "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 specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>before</code> were
-          specified.</p>
-
-          <p>The <code>tts:displayAlign</code> style is illustrated by the following
-          example.</p><a id="style-attribute-displayAlign-example-1" name=
-          "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><a id="style-attribute-displayAlign-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-extent" name="style-attribute-extent"></a>8.2.7
-          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 (which may be the root container
-          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-extent" name=
-          "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> | <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="#document-structure-vocabulary-tt"><code>tt</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 root container region</td>
-              </tr>
-
-              <tr>
-                <td><em>Animatable:</em></td>
-
-                <td>discrete</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>width</em> and <em>height</em>, where the first
-          specification is the <em>width</em>, and the second specification is the
-          <em>height</em>, where, if either <em>width</em> or <em>height</em> is negative
-          or zero, then extent must be considered zero in both inline and block
-          progression dimensions.</p>
-
-          <p>If the value of this attribute is <code>auto</code>, then the initial value
-          of the style property must be considered to be the same as the root container
-          extent.</p>
-
-          <p>The root container extent is determined either by a <code>tts:extent</code>
-          specified on the <code>tt</code> element, if present, or by the external
-          authoring context, 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 specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>auto</code> were
-          specified.</p>
-
-          <p>The <code>tts:extent</code> style is illustrated by the following
-          example.</p><a id="style-attribute-extent-example-1" name=
-          "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><a id="style-attribute-extent-example-1-images" name=
-          "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" name=
-          "style-attribute-fontFamily"></a>8.2.8 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" name=
-          "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-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>8.3.6
-            &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 specified font family is not available, then a presentation processor
-          must attempt to map the specified font family to an available font family that
-          has similar typographic characteristics, or, in the absence of such a mapping,
-          it must interpret the font family as if the value <code>default</code> were
-          specified.</p>
-
-          <p>The <code>tts:fontFamily</code> style is illustrated by the following
-          example.</p><a id="style-attribute-fontFamily-example-1" name=
-          "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><a id="style-attribute-fontFamily-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-fontSize" name="style-attribute-fontSize"></a>8.2.9
-          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, where font size is interpreted as a
-          scaling transform to the font's design EM square.</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" name=
-          "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-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 parent element's font size</td>
-              </tr>
-
-              <tr>
-                <td><em>Animatable:</em></td>
-
-                <td>discrete</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>
-
-          <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 specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>1c</code> were
-          specified.</p>
-
-          <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>8.3.9 &lt;length&gt;</b></a>.</p>
-          </div>
-
-          <p>The <code>tts:fontSize</code> style is illustrated by the following
-          example.</p><a id="style-attribute-fontSize-example-1" name=
-          "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><a id="style-attribute-fontSize-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-fontStyle" name=
-          "style-attribute-fontStyle"></a>8.2.10 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" name=
-          "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-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> denote a shear transformation (at an
-          unspecified angle) in the inline progression dimension.</p>
-
-          <p>If a specified font style is not available, then a presentation processor
-          must attempt to map the specified font style to an available font style that
-          has similar typographic characteristics, or, in the absence of such a mapping,
-          it must interpret the font style as if the value <code>normal</code> were
-          specified.</p>
-
-          <p>The <code>tts:fontStyle</code> style is illustrated by the following
-          example.</p><a id="style-attribute-fontStyle-example-1" name=
-          "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><a id="style-attribute-fontStyle-example-1-images" name=
-          "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>
-        </div>
-
-        <div class="div3">
-          <h4><a id="style-attribute-fontWeight" name=
-          "style-attribute-fontWeight"></a>8.2.11 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" name=
-          "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-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 specified font weight is not available, then a presentation processor
-          must attempt to map the specified font weight to an available font weight that
-          has similar typographic characteristics, or, in the absence of such a mapping,
-          it must interpret the font weight as if the value <code>normal</code> were
-          specified.</p>
-
-          <p>The <code>tts:fontWeight</code> style is illustrated by the following
-          example.</p><a id="style-attribute-fontWeight-example-1" name=
-          "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><a id="style-attribute-fontWeight-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-lineHeight" name=
-          "style-attribute-lineHeight"></a>8.2.12 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>
-
-          <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" name=
-          "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</td>
-              </tr>
-            </tbody>
-          </table>
-
-          <p>If the value of this attribute is <code>normal</code>, then the initial
-          value of the style property must be considered to be the same as the largest
-          font size that applies to any descendant element.</p>
-
-          <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 specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>normal</code> were
-          specified.</p>
-
-          <p>The <code>tts:lineHeight</code> style is illustrated by the following
-          example.</p><a id="style-attribute-lineHeight-example-1" name=
-          "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><a id="style-attribute-lineHeight-example-1-images" name=
-          "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>
-        </div>
-
-        <div class="div3">
-          <h4><a id="style-attribute-opacity" name="style-attribute-opacity"></a>8.2.13
-          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.</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.</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" name=
-          "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="#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>An <a href="#style-value-alpha">&lt;alpha&gt;</a> value greater than 1.0
-          must be considered equivalent to an <a href=
-          "#style-value-alpha">&lt;alpha&gt;</a> value of 1.0.</p>
-
-          <p>The <code>tts:opacity</code> style is illustrated by the following
-          example.</p><a id="style-attribute-opacity-example-1" name=
-          "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><a id="style-attribute-opacity-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-origin" name="style-attribute-origin"></a>8.2.14
-          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 root container extent, if specified, or the external authoring
-          context, if not specified.</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" name=
-          "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="#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 root container region</td>
-              </tr>
-
-              <tr>
-                <td><em>Animatable:</em></td>
-
-                <td>discrete</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 initial value
-          of the style property must be considered to be the same as the root container
-          origin.</p>
-
-          <p>If a specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>auto</code> were
-          specified.</p>
-
-          <p>The <code>tts:origin</code> style is illustrated by the following
-          example.</p><a id="style-attribute-origin-example-1" name=
-          "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><a id="style-attribute-origin-example-1-images" name=
-          "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" name="style-attribute-overflow"></a>8.2.15
-          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" name=
-          "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, and region composition and
-          layout must be performed as if the region's width and height were
-          unconstrained, but with a well-defined origin. 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 value of the <code>tts:overflow</code> style that
-            applies to the region is <code>visible</code> and if the applicable
-            <code>tts:wrapOption</code> style is <code>noWrap</code>.</p>
-          </div>
-
-          <p>If a specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>hidden</code> were
-          specified.</p>
-
-          <p>The <code>tts:overflow</code> style is illustrated by the following
-          example.</p><a id="style-attribute-overflow-example-1" name=
-          "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><a id="style-attribute-overflow-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-padding" name="style-attribute-padding"></a>8.2.16
-          tts:padding</h4>
-
-          <p>The <code>tts:padding</code> attribute is used to specify padding (or inset)
-          space on all sides of 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-padding" name=
-          "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="#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 region</td>
-              </tr>
-
-              <tr>
-                <td><em>Animatable:</em></td>
-
-                <td>discrete</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>If a specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>0px</code> were
-          specified.</p>
-
-          <p>The <code>tts:padding</code> style is illustrated by the following
-          example.</p><a id="style-attribute-padding-example-1" name=
-          "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" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-showBackground" name=
-          "style-attribute-showBackground"></a>8.2.17 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" name=
-          "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 selected into the
-          region.</p>
-
-          <p>If a specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>always</code> were
-          specified.</p>
-
-          <p>The <code>tts:showBackground</code> style is illustrated by the following
-          example.</p><a id="style-attribute-showBackground-example-1" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-textAlign" name=
-          "style-attribute-textAlign"></a>8.2.18 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" name=
-          "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></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>If a specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>start</code> were
-          specified.</p>
-
-          <p>The <code>tts:textAlign</code> style is illustrated by the following
-          example.</p><a id="style-attribute-textAlign-example-1" name=
-          "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><a id="style-attribute-textAlign-example-1-images" name=
-          "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>
-        </div>
-
-        <div class="div3">
-          <h4><a id="style-attribute-textDecoration" name=
-          "style-attribute-textDecoration"></a>8.2.19 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" name=
-          "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 specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>none</code> were
-          specified.</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" name=
-          "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><a id="style-attribute-textDecoration-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-textOutline" name=
-          "style-attribute-textOutline"></a>8.2.20 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" name=
-          "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</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>
-
-          <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 root container
-            extent 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 specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>none</code> were
-          specified.</p>
-
-          <p>The <code>tts:textOutline</code> style is illustrated by the following
-          example.</p><a id="style-attribute-textOutline-example-1" name=
-          "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><a id="style-attribute-textOutline-example-1-images" name=
-          "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=
-                "backgroundColor style property"></td>
-              </tr>
-            </tbody>
-          </table>
-        </div>
-
-        <div class="div3">
-          <h4><a id="style-attribute-unicodeBidi" name=
-          "style-attribute-unicodeBidi"></a>8.2.21 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" name=
-          "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 specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>normal</code> were
-          specified.</p>
-
-          <p>The <code>tts:unicodeBidi</code> style is illustrated by the following
-          example.</p><a id="style-attribute-unicodeBidi-example-1" name=
-          "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><a id="style-attribute-unicodeBidi-example-1-images" name=
-          "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>
-
-        <div class="div3">
-          <h4><a id="style-attribute-visibility" name=
-          "style-attribute-visibility"></a>8.2.22 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" name=
-          "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 specified value of this attribute is not supported, then a presentation
-          processor must interpret the attribute as if the value <code>visible</code>
-          were specified.</p>
-
-          <p>The <code>tts:visibility</code> style is illustrated by the following
-          example.</p><a id="style-attribute-visibility-example-1" name=
-          "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>