[ttml10se]
authorGlenn Adams <glenn@skynav.com>
Thu, 27 Jun 2013 03:45:20 -0600
changeset 413 0fe7753bea57
parent 412 216a924eba20
child 414 af3ea1f5a3e9
[ttml10se]
(1) add SDP US profile to profile list (table 2);
(2) generate new PER-ttaf1-dfxp-201307DD;
ttml10/spec/PER-ttaf1-dfxp-201307DD.html
ttml10/spec/PER-ttaf1-dfxp-201307DD.zip
ttml10/spec/build.xml
ttml10/spec/entitiesper.dtd
ttml10/spec/statusper.xml
ttml10/spec/ttaf1-dfxp.xml
ttml10/spec/ttml-changes.html
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml10/spec/PER-ttaf1-dfxp-201307DD.html	Thu Jun 27 03:45:20 2013 -0600
@@ -0,0 +1,21377 @@
+<!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; }
+
+  ol.enumar      { list-style-type: decimal; }
+  ol.enumla      { list-style-type: lower-alpha; }
+  ol.enumlr      { list-style-type: lower-roman; }
+  ol.enumua      { list-style-type: upper-alpha; }
+  ol.enumur      { list-style-type: upper-roman; }
+
+
+  div.exampleInner pre { margin-left: 1em;
+                       margin-top: 0em; margin-bottom: 0em}
+  div.exampleOuter {border: 4px double gray;
+                  margin: 0em; padding: 0em}
+  div.exampleInner { background-color: #d5dee3;
+                   border-top-width: 4px;
+                   border-top-style: double;
+                   border-top-color: #d3d3d3;
+                   border-bottom-width: 4px;
+                   border-bottom-style: double;
+                   border-bottom-color: #d3d3d3;
+                   padding: 4px; margin: 0em }
+  div.exampleWrapper { margin: 4px }
+  div.exampleHeader { font-weight: bold;
+                    margin: 4px}
+
+  li p { margin-top: 0.3em; margin-bottom: 0.3em; }
+  div.issue { border: 2px solid black; background-color: #ffff66; padding: 0em 1em; margin: 0em 0em }
+  table.ednote { border-collapse: collapse; border: 2px solid black; width: 85% }
+  table.ednote td { background-color: #ddaa66; border: 2px solid black }
+  table.acronyms td.label { width: 15% }
+  table.acronyms td.def { width: 65% }
+  table.graphic { border: 0px none black; width: 100%; border-collapse: collapse }
+  table.graphic caption { font-weight: bold; text-align: center; padding-bottom: 0.5em }
+  table.graphic td { border: 0px none black; text-align: center }
+  table.common { border: 2px solid black; width: 85%; border-collapse: collapse }
+  table.common caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+  table.common th { padding: 0em 0.5em; border: 2px solid black; text-align: left }
+  table.common td { padding: 0em 0.5em; border: 2px solid black }
+  table.syntax { border: 0px solid black; width: 85%; border-collapse: collapse }
+  table.syntax caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+  table.syntax th { border: 0px solid black; text-align: left }
+  table.syntax td { border: 0px solid black }
+  table.syntax div { background-color: #ffffc8 }
+  table.semantics { border: 0px solid black; width: 85%; border-collapse: collapse }
+  table.semantics caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+  table.semantics th { border: 0px solid black; text-align: left }
+  table.semantics td {
+  border-left: 0px solid black;
+  border-right: 0px solid black;
+  border-top: 4px double #d3d3d3;
+  border-bottom: 4px double #d3d3d3;
+  background-color: #ccffcc
+  }
+  table.semantics code.formulae {
+  padding: 1em;
+  border: 1px dashed #005a9c;
+  line-height: 1.1em;
+  background-color: #fdfdfd;
+  }
+  table.example { border: 0px solid black; width: 85%; border-collapse: collapse }
+  table.example caption { font-weight: bold; text-align: left; padding-bottom: 0.5em }
+  table.example th { border: 0px solid black; text-align: left }
+  table.example td { border: 0px solid black;  }
+  table.example div { background-color: #c8ffff }
+  table.example-images { text-align: center; border: 0px solid black; width: 85%; border-collapse: collapse }
+  table.example-images caption { font-weight: bold; text-align: center; padding-bottom: 0.5em }
+  table.example-images td { border: 0px solid black; text-align: center }
+  table.example-images-bordered { text-align: center; border: 0px solid black; width: 85%; border-collapse: collapse }
+  table.example-images-bordered caption { font-weight: bold; text-align: center; padding-bottom: 0.5em }
+  table.example-images-bordered td { border: 1px solid red; text-align: left }
+  .tbd { background-color: #ffff33; border: 2px solid black; width: 85% }
+  .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 July 2013</h2>
+
+    <dl>
+      <dt>This version:</dt>
+
+      <dd><a href=
+      "http://www.w3.org/TR/2013/PER-ttaf1-dfxp-201307DD/">http://www.w3.org/TR/2013/PER-ttaf1-dfxp-201307DD/</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 July 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
+    August 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">Deleted</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">Deleted</a><br>
+    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.3.12 <a href=
+    "#style-value-string">Deleted</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="#d3e18638">Element Derivation</a><br>
+    &nbsp;&nbsp;&nbsp;&nbsp;J.2 <a href="#d3e19117">Attribute
+    Derivation</a><br>
+    K <a href="#qa">QA Framework Compliance</a> (Non-Normative)<br>
+    &nbsp;&nbsp;&nbsp;&nbsp;K.1 <a href="#d3e20003">Requirements</a><br>
+    &nbsp;&nbsp;&nbsp;&nbsp;K.2 <a href="#d3e20167">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 effects of the use of
+        <code>tts:textAlign="center"</code> to specify the paragraph's
+        alignment in the inline progression direction.</p><a id=
+        "ttml-example-subtitle-2" 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>TTAF</b></td>
+
+            <td class="def">
+              <p>Timed Text Authoring Format</p>
+            </td>
+          </tr>
+
+          <tr>
+            <td class="label"><b>TTWG</b></td>
+
+            <td class="def">
+              <p>Timed Text Working Group</p>
+            </td>
+          </tr>
+        </table>
+      </div>
+
+      <div class="div2">
+        <h3><a id="terms" 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">Computed Cell Size</dt>
+
+          <dd>
+            <p>The size (extent) of a cell computed by dividing the width of
+            the <em>Root Container Region</em> (in pixels) by the column count,
+            i.e., the number of cells in the horizontal axis, and by dividing
+            the height of the <em>Root Container Region</em> (in pixels) by the
+            row count, i.e., the number of cells in the vertical axis, where
+            the column and row counts are determined by the
+            <code>ttp:cellResolution</code> parameter attribute.</p>
+          </dd>
+
+          <dt class="label">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">Related Media Object Region</dt>
+
+          <dd>
+            <p>When a non-null <em>Related Media Object</em> exists, the region
+            in which a presentation processor presents this media object.</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>The term linear white-space (LWSP) is to be interpreted as a
+        non-empty sequence of SPACE (U+0020), TAB (U+0009), CARRIAGE RETURN
+        (U+000D), or LINE FEED (U+000A), which corresponds to production [3]
+        <code>S</code> as defined by <a href="#xml10">[XML 1.0]</a>.</p>
+
+        <p>All content of this specification that is not explicitly marked as
+        non-normative is considered to be normative. If a section or appendix
+        header contains the expression "Non-Normative", then the entirety of
+        the section or appendix is considered non-normative.</p>
+
+        <p>All paragraphs marked as a <span class="strong">Note</span> are
+        considered non-normative.</p>
+
+        <p>Example code fragments are depicted with a light blue-green
+        background color and labeled as "Example Fragment", such as in the
+        following:</p><a id="example-fragment-1" 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="#xml-media">[XML Media Types]</a> § 7, with which an
+            optional <code>profile</code> parameter may appear, the value of
+            which conforms to a profile designator as defined by <a href=
+            "#vocabulary-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> or in another TTWG specification.</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>
+
+            <tr>
+              <td>SDP US</td>
+
+              <td><code>http://www.w3.org/ns/ttml/profile/sdp-us</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>All profile designators which have the TT Profile Namespace as a
+        prefix but are otherwise not listed in <a href=
+        "#profile-vocab-table"><b>Table 2 – Profiles</b></a> are reserved for
+        future standardization, and must not be appear in a conformant
+        <em>Document Instance</em>. Nothwithstanding this constraint, 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> provided it does not use the TT Profile Namespace as a
+        prefix.</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>,
+          and, furthermore, the specific designation that appears in this URI,
+          i.e., the portion of the feature designation that starts with the
+          fragment identifier separator '#', must be defined by this
+          specification or some published version thereof (that has achieved
+          REC status).</p>
+
+          <p>If the URI expressed by the content of the
+          <code>ttp:feature</code> element 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/ttml/extension/"&gt;
+    <span class=
+"strong">&lt;ttp:extension value="use"&gt;#prefilter-by-language&lt;/ttp:extension&gt;</span>
+  &lt;/ttp:extensions&gt;
+&lt;/ttp:profile&gt;
+</pre>
+                  </div>
+                </td>
+              </tr>
+            </tbody>
+          </table>
+
+          <div class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>In the above example, the 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 <em>Root Container Region</em> 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>
+
+          <p>Except where indicated otherwise, when a <a href=
+          "#style-value-length">&lt;length&gt;</a> expressed in cells denotes a
+          dimension parallel to the inline or block progression dimension, the
+          cell's dimension in the inline or block progression dimension
+          applies, respectively.</p>
+
+          <div class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>For example, if padding (on all four edges) is specified as
+            0.1c, the cell resolution is 20 by 10, and the extent of the
+            <em>Root Container Region</em> 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 (well-formed) expression of
+          a duration must be considered to be invalid.</p>
+
+          <div class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>When operating with <code>smpte</code> time base and
+            <code>discontinuous</code> marker mode, there is no effective time
+            coordinate space; rather, all time expressions are interpreted as
+            labeled synchronization events (markers), where the <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>In the absence of other requirements, and if a <em>Related Media
+            Object</em> exists, then it is recommended that the <em>Document
+            Processing Context</em> determine that:</p>
+
+            <ul>
+              <li>
+                <p>if no <code>tts:extent</code> is specified on the root
+                <code>tt</code> element, the extent of the <em>Root Container
+                Region</em> be established as equal to the extent of the
+                <em>Related Media Object Region</em>; and</p>
+              </li>
+
+              <li>
+                <p>the origin of the <em>Root Container Region</em> be
+                established so that this region is centered in the <em>Related
+                Media Object Region</em>.</p>
+              </li>
+            </ul>
+          </div>
+
+          <div class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>If an author desires to signal the (storage or image) aspect
+            ratio of the <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>
+
+          <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 except parameter
+          vocabulary.</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 except parameter vocabulary.</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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the above four cited XSL-FO properties are
+            defined by by <a href="#xsl11">[XSL 1.1]</a>, § 7.17.3, 7.16.7,
+            7.16.12, and 7.16.8, respectively.</p>
+          </div>
+        </div>
+      </div>
+    </div>
+
+    <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 effects of the attributes in
+      this section are intended to be compatible with the layout and formatting
+      model of XSL; however, Presentation agents may use any technology to
+      satisfy the authorial intent of the document. In particular since
+      <a href="#css2">[CSS2]</a> is a subset of this model, a CSS processor may
+      be used for the features that the models have in common.</p>
+
+      <p>No normative use of an <code>&lt;?xml-stylesheet ... ?&gt;</code>
+      processing instruction is defined by this specification.</p>
+
+      <div class="div2">
+        <h3><a id="styling-element-vocabulary" 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>
+      </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 style (property) set.</p>
+
+          <p>The <code>style</code> attribute may be specified by an instance
+          of the following element types:</p>
+
+          <ul>
+            <li>
+              <p><a href=
+              "#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, and, furthermore, each
+          IDREF must reference a <code>style</code> element which has a
+          <code>styling</code> element as an ancestor.</p>
+
+          <p>If the same IDREF, <em>ID<sub>1</sub></em>, appears more than one
+          time in the value of a <code>style</code> attribute, then there
+          should be an intervening IDREF, <em>ID<sub>2</sub></em>, where
+          <em>ID<sub>2</sub></em> is not equal to <em>ID<sub>1</sub></em>.</p>
+
+          <div class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>This constraint is intended to discourage the use of redundant
+            referential styling while still allowing the same style to be
+            referenced multiple times in order to potentially override prior
+            referenced styles, e.g., when an intervening, distinct style is
+            referenced in the IDREFS list.</p>
+          </div>
+
+          <div class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>See the specific element type definitions that permit use of the
+            <code>style</code> attribute, as well as <a href=
+            "#semantics-style-association-referential"><b>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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.8.2.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-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 <em>Root Container Region</em>.</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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.18.1.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-direction" 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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.29.1.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-display" 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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href=
+            "#css2">[CSS2]</a>, § 9.2.4.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-displayAlign" 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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.14.4.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-extent" 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
+          <em>Root Container Region</em>).</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 <em>Root Container
+                Region</em></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>.</p>
+
+          <p>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used
+          to express extent must be non-negative.</p>
+
+          <p>If the value of this attribute is <code>auto</code>, then the
+          initial value of the style property must be considered to be the same
+          as the extent of the <em>Root Container Region</em>.</p>
+
+          <p>The extent of the <em>Root Container Region</em> is determined
+          either by a <code>tts:extent</code> specified on the <code>tt</code>
+          element, if present, or as described by <a href=
+          "#document-structure-vocabulary-tt"><b>7.1.1 tt</b></a> if not
+          present. If <code>tts:extent</code> is specified on the
+          <code>tt</code> element, then the width and height must be expressed
+          in terms of two <a href="#style-value-length">&lt;length&gt;</a>
+          specifications, and these specifications must be expressed as
+          non-percentage, definite lengths using pixel units.</p>
+
+          <p>If a 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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.9.2.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-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.</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, or if no parent
+                element, then relative to the <em>Computed Cell Size</em></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 closest
+          supported value 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>.
+            When a single &lt;length&gt; is expressed using cell units, then it
+            refers to the height of the <em>Computed Cell Size</em>.</p>
+          </div>
+
+          <div class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>As specified above, the use of percentage units to express font
+            size are interpreted as relative to <em>Computed Cell Size</em>
+            when there is no parent element. For example, if cell resolution is
+            32 by 15, and the extent of the <em>Root Container Region</em> is
+            640 by 480, then the <em>Computed Cell Size</em> is [20px, 32px],
+            i.e., 640px/32 (width) and 480px/15 (height). Consequently, if
+            <code>tts:fontSize</code> were specified as 75% on the root
+            <code>tt</code> element, then this would be equivalent to
+            specifying 24px, i.e., 32px cell height * 75%. If two length
+            expressions (independent horizontal and vertical font scaling) were
+            specified, e.g., "80% 75%", then this would be equivalent to
+            specifying "16px 24px", i.e., 80% of 20px cell width is 16px, and
+            75% of 32px cell height is 24px.</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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.9.4. The addition of a second length component to
+            permit specifying font width and height independently is an
+            extension introduced by TTML.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-fontStyle" 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> denotes 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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.9.7.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.9.9.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.16.4. Furthermore, it is the intention of this
+            specification that the allocation rectangle of a line be consistent
+            with the <span class="strong">per-inline-height-rectangle</span> as
+            defined by <a href="#xsl11">[XSL 1.1]</a>, § 4.5, i.e., that a
+            CSS-style line box stacking strategy be used.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-opacity" 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>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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href=
+            "#css3-color">[CSS3 Color]</a>, § 3.2.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-origin" 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 <em>Root Container Region</em>.</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 <em>Root Container
+                Region</em></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 origin of the <em>Root Container Region</em>.</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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.21.2.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-padding" 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>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used
+          to express padding 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>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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.31.15, except that individual shorthand values map to
+            writing mode relative padding values as defined by <a href=
+            "#xsl11">[XSL 1.1]</a>, § 7.8.31, 7.8.32, 7.8.33, and 7.8.34.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-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 flowed 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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#smil21">[SMIL
+            2.1]</a>, § 5.3.3.</p>
+          </div>
+        </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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.16.9.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.17.4.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-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>
+
+          <p>The <a href="#style-value-length">&lt;length&gt;</a> value(s) used
+          to express thickness and blur radius must be non-negative.</p>
+
+          <div class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>When a <a href="#style-value-length">&lt;length&gt;</a>
+            expressed in cells is used in a <code>tts:textOutline</code> value,
+            the cell's dimension in the block progression dimension applies.
+            For example, if text outline thickness is specified as 0.1c, the
+            cell resolution is 20 by 10, and the extent of the <em>Root
+            Container Region</em> 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 class="note">
+            <p class="prefix"><b>Note:</b></p>
+
+            <p>The semantics of the style property represented by this
+            attribute are based upon that defined by <a href="#xsl11">[XSL
+            1.1]</a>, § 7.29.6.</p>
+          </div>
+        </div>
+
+        <div class="div3">
+          <h4><a id="style-attribute-visibility" 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>
+              </t