--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ttml-ww-profiles/ttml-ww-profiles.html Wed Dec 11 15:44:39 2013 -0500
@@ -0,0 +1,2475 @@
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+
+<body id="respecDocument" role="document" class="h-entry"><div id="respecHeader" role="contentinfo" class="head">
+ <p>
+
+ <a href="http://www.w3.org/"><img src="https://www.w3.org/Icons/w3c_home" alt="W3C" height="48" width="72"></a>
+
+ </p>
+ <h1 class="title p-name" id="title" property="dcterms:title">TTML Text and Image Profiles for Internet Media Subtitles and Captions</h1>
+
+ <h2 id="w3c-editor-s-draft-11-december-2013" property="dcterms:issued" datatype="xsd:dateTime" content="2013-12-11T20:42:30.000Z"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft <time class="dt-published" datetime="2013-12-11">11 December 2013</time></h2>
+ <dl>
+
+ <dt>This version:</dt>
+ <dd><a class="u-url" href=""></a></dd>
+ <dt>Latest published version:</dt>
+ <dd><a href="http://www.w3.org/TR/ttml-ww-profiles/">http://www.w3.org/TR/ttml-ww-profiles/</a></dd>
+
+
+
+
+
+
+
+
+
+ <dt>Editor:</dt>
+ <dd class="p-author h-card vcard" rel="bibo:editor" inlist=""><span typeof="foaf:Person"><span property="foaf:name" class="p-name fn">Pierre Lemieux</span>, <span class="ed_mailto"><a class="u-email email" rel="foaf:mbox" href="mailto:pal@sandflow.com">pal@sandflow.com</a></span></span>
+</dd>
+
+
+
+ </dl>
+
+
+
+
+
+ <p class="copyright">
+ <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> ©
+ 2013
+
+ <a href="http://www.w3.org/"><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup>
+ (<a href="http://www.csail.mit.edu/"><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>,
+ <a href="http://www.ercim.eu/"><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>,
+ <a href="http://www.keio.ac.jp/">Keio</a>, <a href="http://ev.buaa.edu.cn/">Beihang</a>),
+
+ All Rights Reserved.
+
+ <abbr title="World Wide Web Consortium">W3C</abbr> <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>
+
+
+ <hr>
+</div>
+ <section rel="bibo:Chapter" resource="#ref" typeof="bibo:Chapter" datatype="" property="dcterms:abstract" class="introductory" id="abstract"><h2 id="h2_abstract" role="heading" aria-level="1">Abstract</h2>
+ <p>This document specifies two profiles of [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>]: a text-only profile and an image-only
+ profile. These profiles are intended to be used across subtitle and caption delivery applications worldwide, thereby
+ simplifying interoperability, consistent rendering and conversion to other subtitling and captioning formats. The text profile
+ is a superset of [<cite><a href="#bib-SDPUS" class="bibref">SDPUS</a></cite>].</p>
+
+ <p>Both profiles are based on [<cite><a href="#bib-SUBM" class="bibref">SUBM</a></cite>].</p>
+ </section><section rel="bibo:Chapter" resource="#ref" typeof="bibo:Chapter" id="sotd" class="introductory"><h2 id="h2_sotd" role="heading" aria-level="1">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 <abbr title="World Wide Web Consortium">W3C</abbr> publications and the
+ latest revision of this technical report can be found in the <a href="http://www.w3.org/TR/"><abbr title="World Wide Web Consortium">W3C</abbr> technical reports index</a> at
+ http://www.w3.org/TR/.</em>
+ </p>
+
+ <p>
+ This document was published by the <a href="http://www.w3.org/AudioVideo/TT/">Timed Text Working Group</a> as an Editor's Draft.
+
+
+ If you wish to make comments regarding this document, please send them to
+ <a href="mailto:public-tt@w3.org">public-tt@w3.org</a>
+ (<a href="mailto:public-tt-request@w3.org?subject=subscribe">subscribe</a>,
+ <a href="http://lists.w3.org/Archives/Public/public-tt/">archives</a>).
+
+
+
+
+ All comments are welcome.
+
+ </p>
+
+
+ <p>
+ Publication as an Editor's Draft does not imply endorsement by the <abbr title="World Wide Web Consortium">W3C</abbr>
+ 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>
+
+ This document was produced by a group operating under the
+ <a id="sotd_patent" about="" rel="w3p:patentRules" href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 <abbr title="World Wide Web Consortium">W3C</abbr> Patent
+ Policy</a>.
+
+
+
+
+ <abbr title="World Wide Web Consortium">W3C</abbr> maintains a <a href="http://www.w3.org/2004/01/pp-impl/34314/status" 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 <abbr title="World Wide Web Consortium">W3C</abbr> Patent Policy</a>.
+
+
+ </p>
+
+
+
+
+</section><section id="toc"><h2 id="h2_toc" role="heading" aria-level="1" class="introductory">Table of Contents</h2><ul id="respecContents" role="directory" class="toc"><li class="tocline"><a class="tocxref" href="#scope"><span class="secno">1. </span>Scope</a></li><li class="tocline"><a class="tocxref" href="#conformance"><span class="secno">2. </span>Conformance</a></li><li class="tocline"><a class="tocxref" href="#profiles"><span class="secno">3. </span>Profiles</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#general"><span class="secno">3.1 </span>General</a></li><li class="tocline"><a class="tocxref" href="#text-profile"><span class="secno">3.2 </span>Text Profile</a></li><li class="tocline"><a class="tocxref" href="#image-profile"><span class="secno">3.3 </span>Image Profile</a></li></ul></li><li class="tocline"><a class="tocxref" href="#common-constraints"><span class="secno">4. </span>Common Constraints</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#document-encoding"><span class="secno">4.1 </span>Document Encoding</a></li><li class="tocline"><a class="tocxref" href="#namespaces"><span class="secno">4.2 </span>Namespaces</a></li><li class="tocline"><a class="tocxref" href="#related-video-object"><span class="secno">4.3 </span>Related Video Object</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#general-1"><span class="secno">4.3.1 </span>General</a></li><li class="tocline"><a class="tocxref" href="#root-container"><span class="secno">4.3.2 </span>Root Container</a></li><li class="tocline"><a class="tocxref" href="#synchronization"><span class="secno">4.3.3 </span>Synchronization</a></li></ul></li><li class="tocline"><a class="tocxref" href="#progressively-decodable"><span class="secno">4.4 </span>Progressively Decodable</a></li><li class="tocline"><a class="tocxref" href="#region"><span class="secno">4.5 </span>Region</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#presented-region"><span class="secno">4.5.1 </span>Presented Region</a></li><li class="tocline"><a class="tocxref" href="#dimensions-and-position"><span class="secno">4.5.2 </span>Dimensions and Position</a></li><li class="tocline"><a class="tocxref" href="#maximum-number"><span class="secno">4.5.3 </span>Maximum number</a></li></ul></li><li class="tocline"><a class="tocxref" href="#hypothetical-render-model"><span class="secno">4.6 </span>Hypothetical Render Model</a></li><li class="tocline"><a class="tocxref" href="#features"><span class="secno">4.7 </span>Features</a></li></ul></li><li class="tocline"><a class="tocxref" href="#text-profile-constraints"><span class="secno">5. </span>Text Profile Constraints</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#profile-designator-and-definition-document"><span class="secno">5.1 </span>Profile Designator and Definition Document</a></li><li class="tocline"><a class="tocxref" href="#recommended-character-sets"><span class="secno">5.2 </span>Recommended Character Sets</a></li><li class="tocline"><a class="tocxref" href="#features-1"><span class="secno">5.3 </span>Features</a></li></ul></li><li class="tocline"><a class="tocxref" href="#image-profile-constraints"><span class="secno">6. </span>Image Profile Constraints</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#profile-designator-and-definition-document-1"><span class="secno">6.1 </span>Profile Designator and Definition Document</a></li><li class="tocline"><a class="tocxref" href="#presented-image"><span class="secno">6.2 </span>Presented Image</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#definition"><span class="secno">6.2.1 </span>Definition</a></li><li class="tocline"><a class="tocxref" href="#number-per-region"><span class="secno">6.2.2 </span>Number per Region</a></li></ul></li><li class="tocline"><a class="tocxref" href="#div-element"><span class="secno">6.3 </span><code>div</code> element</a></li><li class="tocline"><a class="tocxref" href="#features-2"><span class="secno">6.4 </span>Features</a></li></ul></li><li class="tocline"><a class="tocxref" href="#hypothetical-render-model-1"><span class="secno">7. </span>Hypothetical Render Model</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#performance-model"><span class="secno">7.1 </span>Performance Model</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#overview"><span class="secno">7.1.1 </span>Overview</a></li><li class="tocline"><a class="tocxref" href="#general-2"><span class="secno">7.1.2 </span>General</a></li><li class="tocline"><a class="tocxref" href="#paint-regions"><span class="secno">7.1.3 </span>Paint Regions</a></li><li class="tocline"><a class="tocxref" href="#paint-images"><span class="secno">7.1.4 </span>Paint Images</a></li><li class="tocline"><a class="tocxref" href="#paint-text"><span class="secno">7.1.5 </span>Paint Text</a></li></ul></li><li class="tocline"><a class="tocxref" href="#layout-model"><span class="secno">7.2 </span>Layout Model</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#general-3"><span class="secno">7.2.1 </span>General</a></li><li class="tocline"><a class="tocxref" href="#reference-fonts"><span class="secno">7.2.2 </span>Reference Fonts</a></li><li class="tocline"><a class="tocxref" href="#line-height-and-centering"><span class="secno">7.2.3 </span>Line Height and Centering</a></li></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#recommended-character-sets-1"><span class="secno">A. </span>Recommended Character Sets</a></li><li class="tocline"><a class="tocxref" href="#schema"><span class="secno">B. </span>Schema</a></li><li class="tocline"><a class="tocxref" href="#references"><span class="secno">C. </span>References</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#normative-references"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a class="tocxref" href="#informative-references"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></section>
+
+ <section rel="bibo:Chapter" resource="#ref" typeof="bibo:Chapter" id="scope">
+ <!--OddPage--><h2 id="h2_scope" role="heading" aria-level="1"><span class="secno">1. </span>Scope</h2>
+
+ <p>This document specifies two profiles of [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>]: a text-only profile and an image-only profile. These profiles are
+ intended for subtitle and caption delivery worldwide, including dialog language translation, content description, captions for
+ deaf and hard of hearing, etc.</p>
+
+ <p>The profiles are strict subset of [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>] and the text-only profile a strict supersets of [<cite><a href="#bib-SDPUS" class="bibref">SDPUS</a></cite>].</p>
+ </section>
+
+ <section rel="bibo:Chapter" resource="#ref" typeof="bibo:Chapter" id="conformance"><!--OddPage--><h2 id="h2_conformance" role="heading" aria-level="1"><span class="secno">2. </span>Conformance</h2>
+<p>
+ As well as sections marked as non-normative, all authoring guidelines, diagrams, examples,
+ and notes in this specification are non-normative. Everything else in this specification is
+ normative.
+</p>
+<p>
+ The key words <em title="MUST" class="rfc2119">MUST</em>, <em title="MUST NOT" class="rfc2119">MUST NOT</em>, <em title="REQUIRED" class="rfc2119">REQUIRED</em>, <em title="SHOULD" class="rfc2119">SHOULD</em>, <em title="SHOULD NOT" class="rfc2119">SHOULD NOT</em>, <em title="RECOMMENDED" class="rfc2119">RECOMMENDED</em>, <em title="MAY" class="rfc2119">MAY</em>,
+ and <em title="OPTIONAL" class="rfc2119">OPTIONAL</em> in this specification are to be interpreted as described in [<cite><a href="#bib-RFC2119" class="bibref">RFC2119</a></cite>].
+</p>
+
+ <p>A subtitle document <em title="SHALL" class="rfc2119">SHALL</em> conform to a profile defined herein if it meets all normative provisions associated with the
+ profile.</p>
+
+ <p>A TTML presentation processor <em title="SHALL" class="rfc2119">SHALL</em> conform to a profile if it is capable of presenting any subtitle document conforming to
+ the profile, i.e. if it implements all features and provisions of the profile</p>
+ </section>
+
+ <section id="profiles">
+ <!--OddPage--><h2 id="h2_profiles" role="heading" aria-level="1"><span class="secno">3. </span>Profiles</h2>
+
+ <section id="general">
+ <h3 id="h3_general" role="heading" aria-level="2"><span class="secno">3.1 </span>General</h3>
+
+ <p>A subtitle document <em title="SHALL NOT" class="rfc2119">SHALL NOT</em> conform to the Text and Image Profiles simultaneously.</p>
+ </section>
+
+ <section id="text-profile">
+ <h3 id="h3_text-profile" role="heading" aria-level="2"><span class="secno">3.2 </span>Text Profile</h3>
+
+ <p>A subtitle document conforming to the Text Profile <em title="SHALL" class="rfc2119">SHALL</em> conform to Sections <a class="sec-ref" href="#common-constraints"><span class="secno">4.</span> <span class="sec-title">Common Constraints</span></a> and
+ <a class="sec-ref" href="#text-profile-constraints"><span class="secno">5.</span> <span class="sec-title">Text Profile Constraints</span></a>.</p>
+ </section>
+
+ <section id="image-profile">
+ <h3 id="h3_image-profile" role="heading" aria-level="2"><span class="secno">3.3 </span>Image Profile</h3>
+
+ <p>A subtitle document conforming to the Image Profile <em title="SHALL" class="rfc2119">SHALL</em> conform to Sections <a class="sec-ref" href="#common-constraints"><span class="secno">4.</span> <span class="sec-title">Common Constraints</span></a> and
+ <a class="sec-ref" href="#image-profile-constraints"><span class="secno">6.</span> <span class="sec-title">Image Profile Constraints</span></a>.</p>
+ </section>
+ </section>
+
+ <section id="common-constraints">
+ <!--OddPage--><h2 id="h2_common-constraints" role="heading" aria-level="1"><span class="secno">4. </span>Common Constraints</h2>
+
+ <section id="document-encoding">
+ <h3 id="h3_document-encoding" role="heading" aria-level="2"><span class="secno">4.1 </span>Document Encoding</h3>
+
+ <p>A subtitle document <em title="SHALL" class="rfc2119">SHALL</em> use UTF-8 character encoding as specified in [<cite><a href="#bib-UNICODE" class="bibref">UNICODE</a></cite>].</p>
+ </section>
+
+ <section id="namespaces">
+ <h3 id="h3_namespaces" role="heading" aria-level="2"><span class="secno">4.2 </span>Namespaces</h3>
+
+ <p>The following namespaces (see [<cite><a href="#bib-xml-names" class="bibref">xml-names</a></cite>]) are used in this specification:</p>
+
+ <table class="simple">
+ <thead>
+ <tr>
+ <th>Prefix</th>
+
+ <th>Value</th>
+ </tr>
+ </thead>
+
+ <tbody>
+ <tr>
+ <td>imsc</td>
+
+ <td>http://www.w3.org/ns/ttml/profile/imsc</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <p>The namespace prefix values defined above are for convenience and document instances may use any prefix value that
+ conforms to [<cite><a href="#bib-xml-names" class="bibref">xml-names</a></cite>].</p>
+ </section>
+
+ <section id="related-video-object">
+ <h3 id="h3_related-video-object" role="heading" aria-level="2"><span class="secno">4.3 </span>Related Video Object</h3>
+
+ <section id="general-1">
+ <h4 id="h4_general-1" role="heading" aria-level="3"><span class="secno">4.3.1 </span>General</h4>
+
+ <p>A subtitle document <em title="MAY" class="rfc2119">MAY</em> be associated with a related video object, which <em title="SHALL" class="rfc2119">SHALL</em> consist of a sequence of frames, each a
+ rectangular array of pixels.</p>
+ </section>
+
+ <section id="root-container">
+ <h4 id="h4_root-container" role="heading" aria-level="3"><span class="secno">4.3.2 </span>Root Container</h4>
+
+ <div class="issue"><div id="h_issue_1" role="heading" aria-level="4" class="issue-title"><span>Issue 1</span></div><p class="">See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/201">ISSUE-201</a> for a discussion of aspect
+ ratio in the context of [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>].</p></div>
+
+ <p>The root container of a subtitle document <em title="SHALL" class="rfc2119">SHALL</em> be mapped to the related video object frame according to the
+ following:</p>
+
+ <ol>
+ <li>
+ <p>If <code>ttp:aspectRatio</code> is present, the root container <em title="SHALL" class="rfc2119">SHALL</em> be mapped to a rectangular area within the
+ related video object such that:</p>
+
+ <ol style="list-style-type: lower-roman;">
+ <li>the aspect ratio of the rectangular area is equal to <code>ttp:aspectRatio</code>,</li>
+
+ <li>the center of the rectangular area is colocated with the center of the related video object frame,</li>
+
+ <li>the rectangular area (including its boundary) is entirely within the related video object frame (including its boundary), and</li>
+
+ <li>the rectangular area has a height or width equal to that of the related video object frame.</li>
+ </ol>
+ </li>
+
+ <li>
+ <p>Otherwise, the root container of a subtitle document <em title="SHALL" class="rfc2119">SHALL</em> be mapped to the related video object frame in its
+ entirety. If <code>tts:extent</code> is present on the <code>tt</code> element, the extents of the root container <em title="SHALL" class="rfc2119">SHALL</em>
+ be equal to the dimensions of the related video object frame.</p>
+ </li>
+ </ol>
+
+ <p><code>ttp:aspectRatio</code> <em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be present if <code>tts:extent</code> is present.<br></p>
+
+ <div class="note"><div id="h_note_1" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">As specified in Section <a class="sec-ref" href="#features"><span class="secno">4.7</span> <span class="sec-title">Features</span></a>, <code>tts:extent</code> is present if the <code>px</code>
+ length measure is used anywhere within the document.</p></div>
+
+ <p>Integer pixel positions on the related video object frame computed from real percentage length values <em title="SHALL" class="rfc2119">SHALL</em> use half-up
+ rounding, i.e. round(x) = floor(x+0.5).</p>
+ </section>
+
+ <section id="synchronization">
+ <h4 id="h4_synchronization" role="heading" aria-level="3"><span class="secno">4.3.3 </span>Synchronization</h4>
+
+ <p>Each intermediate synchronic document of the subtitle document is intended to be displayed on a specific frame and
+ removed on a specific frame of the related video object.</p>
+
+ <p>A media time expression M <em title="SHALL" class="rfc2119">SHALL</em> correspond to the frame of the related video object with the presentation time that is
+ the closest to, but not less, than M.</p>
+
+ <p>If <code>ttp:frameRate</code> is specified, then the product of <code>ttp:frameRate</code> and
+ <code>ttp:frameRateMultiplier</code> <em title="SHALL" class="rfc2119">SHALL</em> be the frame rate of the related video object.</p>
+
+ <aside class="example"><div class="example-title"><span>Example 1</span></div>
+ A media time expression of 00:00:05.1 corresponds to frame ceiling(5.1 × ( 1000 / 1001 × 30) = 153 of a related video
+ object with a frame rate of 1000 / 1001 × 30 ≈ 29.97.
+ </aside>
+ </section>
+ </section>
+
+ <section id="progressively-decodable">
+ <h3 id="h3_progressively-decodable" role="heading" aria-level="2"><span class="secno">4.4 </span>Progressively Decodable</h3>
+
+ <p>A progressively decodable subtitle document is a subtitle document structured to facilitate processing before the document
+ is received in its entirety. It shall conform to the following:</p>
+
+ <ol>
+ <li>elements appear in the document in increasing order according to their resolved begin time;</li>
+
+ <li>no element references another element (i) occurring later in the document or (ii) with a later begin time; and</li>
+
+ <li>a <code>imsc:progressivelyDecodable</code> attribute with value "true" is present on the <code>tt</code>
+ element.</li>
+ </ol>
+
+ <p>The <code>imsc:progressivelyDecodable</code> attribute shall conform to the following syntax:</p>
+
+ <table class="syntax">
+ <tbody>
+ <tr>
+ <td>
+ <div class="exampleInner">
+ <pre>imsc:progressivelyDecodable
+ : "true"
+ | "false"
+</pre>
+ </div>
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <p>The initial value of <code>imsc:progressivelyDecodable</code> shall be "false".</p>
+
+ <p>A <code>imsc:progressivelyDecodable</code> attribute with value "false" may be present on the <code>tt</code>
+ element if the subtitle document is not a progressively decodable subtitle document.</p>
+
+ <p>A <code>imsc:progressivelyDecodable</code> attribute is considered to be significant only when specified on the
+ <code>tt</code> element.</p>
+
+ <div class="note"><div id="h_note_2" role="heading" aria-level="3" class="note-title"><span>Note</span></div><p class="">The placement and use of <code>div</code>, <code>region</code> and <code>span</code> that contain time
+ attributes, and (ii) the use of <code>set</code>.</p></div>
+ </section>
+
+ <section id="region">
+ <h3 id="h3_region" role="heading" aria-level="2"><span class="secno">4.5 </span>Region</h3>
+
+ <section id="presented-region">
+ <h4 id="h4_presented-region" role="heading" aria-level="3"><span class="secno">4.5.1 </span>Presented Region</h4>
+
+ <p>A region, as defined in [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>], <em title="SHALL" class="rfc2119">SHALL</em> be considered presented in a given intermediate synchronic document if all of
+ the following conditions are true:</p>
+
+ <ol>
+ <li>
+ <p><code>tts:opacity</code> is not equal to "0.0" for the region; and</p>
+ </li>
+
+ <li>
+ <p><code>tts:display</code> is not "none"; and</p>
+ </li>
+
+ <li>
+ <p>content is selected into the region or <code>tts:showBackground</code> is equal to "always" for the
+ region.</p>
+ </li>
+ </ol>
+
+ <div class="note"><div id="h_note_3" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">As specified in [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>], the initial value of <code>tts:opacity</code> is "1.0", the initial
+ value of <code>tts:showBackground</code> is "always", and the initial value of <code>tts:display</code> is
+ "auto"</p></div>
+ </section>
+
+ <section id="dimensions-and-position">
+ <h4 id="h4_dimensions-and-position" role="heading" aria-level="3"><span class="secno">4.5.2 </span>Dimensions and Position</h4>
+
+ <p>All regions <em title="SHALL" class="rfc2119">SHALL</em> be entirely contained within the root container, i.e. the intersection of the sets of coordinates belonging to a region (including its boundary) and the sets of coordinates belonging to the root container (including its boundary) is the set of coordinates belonging to the region (including its boundary).</p>
+
+ <p>No two presented regions in a given intermediate synchronic document <em title="SHALL" class="rfc2119">SHALL</em> overlap, i.e. the intersection of the sets of coordinates within each region (including its boundary) is empty.</p>
+ </section>
+
+ <section id="maximum-number">
+ <h4 id="h4_maximum-number" role="heading" aria-level="3"><span class="secno">4.5.3 </span>Maximum number</h4>
+
+ <p>The number of presented regions in a given intermediate synchronic document <em title="SHALL" class="rfc2119">SHALL</em> be smaller than or equal to 4.</p>
+ </section>
+ </section>
+
+ <section id="hypothetical-render-model">
+ <h3 id="h3_hypothetical-render-model" role="heading" aria-level="2"><span class="secno">4.6 </span>Hypothetical Render Model</h3>
+
+ <p>Any sequence of consecutive intermediate synchronic documents <em title="SHALL" class="rfc2119">SHALL</em> be reproducible without error by the Hypothetical
+ Render Model specified in Section <a href="#h2_hypothetical-render-model-1"></a>.</p>
+ </section>
+
+ <section id="features">
+ <h3 id="h3_features" role="heading" aria-level="2"><span class="secno">4.7 </span>Features</h3>
+
+ <p>Unless specified otherwise, the features included in a subtitle document <em title="SHALL" class="rfc2119">SHALL</em> conform to the Table below:</p>
+
+ <table class="simple">
+ <thead>
+ <tr>
+ <th>Feature</th>
+
+ <th>Provisions</th>
+ </tr>
+ </thead>
+
+ <tbody>
+ <tr>
+ <td><code>#animation</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#cellResolution</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#clockMode</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#content</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#core</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#display-block</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#display-inline</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#display-region</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#display</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#dropMode</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#extent-region</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. The <code>tts:extent</code> attribute <em title="SHALL" class="rfc2119">SHALL</em> be present on all <code>region</code> elements.</td>
+ </tr>
+
+ <tr>
+ <td><code>#extent-root</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. If the document includes any length value that uses the <code>px</code> expression,
+ <code>tts:extent</code> <em title="SHALL" class="rfc2119">SHALL</em> be present on the <code>tt</code> element.</td>
+ </tr>
+
+ <tr>
+ <td><code>#extent</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#frameRate</code></td>
+
+ <td>If the document includes any time expression that uses the frame field, the <code>ttp:frameRate</code> attribute
+ <em title="SHALL" class="rfc2119">SHALL</em> be present on the <code>tt</code> element.</td>
+ </tr>
+
+ <tr>
+ <td><code>#frameRateMultiplier</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#layout</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-cell</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-integer</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-negative</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-percentage</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-pixel</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-positive</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-real</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#markerMode</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#metadata</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#opacity</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#origin</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#overflow</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#pixelAspectRatio</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#presentation</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#profile</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#showBackground</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#structure</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#styling-chained</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#styling-inheritance-content</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#styling-inheritance-region</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#styling-inline</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#styling-nested</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#styling-referential</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#styling</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#subFrameRate</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#tickRate</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. <code>ttp:tickRate</code> <em title="SHALL" class="rfc2119">SHALL</em> be present on the <code>tt</code> element if the
+ #time-offset-with-ticks feature is used in the document.</td>
+ </tr>
+
+ <tr>
+ <td><code>#timeBase-clock</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#timeBase-media</code></td>
+
+ <td><em title="SHALL" class="rfc2119">SHALL</em> be used. <code>ttp:timeBase</code> <em title="SHALL" class="rfc2119">SHALL</em> be present on the <code>tt</code> element and <em title="SHALL" class="rfc2119">SHALL</em> be equal to
+ "media".</td>
+ </tr>
+
+ <tr>
+ <td><code>#timeBase-smpte</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#time-clock-with-frames</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#time-clock</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#time-offset-with-frames</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#time-offset-with-ticks</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#time-offset</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#timeContainer</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#timing</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. The same syntax of <code>#clock-time</code> or <code>#offset-time</code> <em title="SHOULD" class="rfc2119">SHOULD</em> be used throughout the
+ subtitle document.</td>
+ </tr>
+
+ <tr>
+ <td><code>#transformation</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#unicodeBidi</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#visibility-block</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#visibility-inline</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#visibility-region</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#visibility</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#writingMode-horizontal-lr</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#writingMode-horizontal-rl</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#writingMode-horizontal</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#writingMode</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#zIndex</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#aspectRatio</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#forcedDisplay</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <div class="issue"><div id="h_issue_2" role="heading" aria-level="3" class="issue-title"><span>Issue 2</span></div><p class="">See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/230">ISSUE-230</a> for a description of
+ <code>#forcedDisplay</code></p></div>
+
+ <div class="note"><div id="h_note_4" role="heading" aria-level="3" class="note-title"><span>Note</span></div><p class="">As specified in [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>], a <code>#time-offset-with-frames</code> expression is translated to a media time
+ M according to M = 3600 · hours + 60 · minutes + seconds + (frames ÷ (<code>ttp:frameRateMultiplier</code> ·
+ <code>ttp:frameRate</code>)).</p></div>
+ </section>
+ </section>
+
+ <section id="text-profile-constraints">
+ <!--OddPage--><h2 id="h2_text-profile-constraints" role="heading" aria-level="1"><span class="secno">5. </span>Text Profile Constraints</h2>
+
+ <section id="profile-designator-and-definition-document">
+ <h3 id="h3_profile-designator-and-definition-document" role="heading" aria-level="2"><span class="secno">5.1 </span>Profile Designator and Definition Document</h3>
+
+ <div class="issue"><div id="h_issue_3" role="heading" aria-level="3" class="issue-title"><span>Issue 3</span></div><p class="">This Section is a placeholder and will be revisited based the outcome of the [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>] profile discussions.</p></div>
+
+ <p>A subtitle document conforming to the Text Profile <em title="SHALL" class="rfc2119">SHALL</em> be associated with the following profile designator and profile
+ definition document:</p>
+ <pre><?xml version="1.0" encoding="utf-8"?>
+<profile designator="http://www.w3.org/ns/ttml/profile/imsc/text/designator" xmlns="http://www.w3.org/ns/ttml#parameter">
+ <extensions>
+ <extension>http://www.w3.org/ns/ttml/profile/imsc/text/feature#all</extension>
+ </extensions>
+</profile>
+</pre>
+ </section>
+<section id="recommended-character-sets">
+ <h3 id="h3_recommended-character-sets" role="heading" aria-level="2"><span class="secno">5.2 </span>Recommended Character Sets</h3>
+
+ <p></p>Authors should to select from the sets of characters specified in <a class="sec-ref" href="#recommended-character-sets-1"><span class="secno">A.</span> <span class="sec-title">Recommended Character Sets</span></a><p></p>
+ </section>
+ <section id="features-1">
+ <h3 id="h3_features-1" role="heading" aria-level="2"><span class="secno">5.3 </span>Features</h3>
+
+ <div class="issue"><div id="h_issue_4" role="heading" aria-level="3" class="issue-title"><span>Issue 4</span></div><p class="">The following assumes, but does not require, the porting of the [<cite><a href="#bib-ST2052-1" class="bibref">ST2052-1</a></cite>] <code>#backgroundImage</code>
+ features to [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>]. See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/238">ISSUE-238</a>.</p></div>
+
+ <p>The features included in a subtitle document <em title="SHALL" class="rfc2119">SHALL</em> conform to the Table below:</p>
+
+ <table class="simple">
+ <thead>
+ <tr>
+ <th>Feature</th>
+
+ <th>Provisions</th>
+ </tr>
+ </thead>
+
+ <tbody>
+ <tr>
+ <td><code>#backgroundColor-block</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#backgroundColor-inline</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#backgroundColor-region</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#backgroundColor</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#backgroundImage</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#backgroundImageHorizontal</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#backgroundImageVertical</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#bidi</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#color</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. The initial value of <code>tts:color</code> <em title="SHALL" class="rfc2119">SHALL</em> be "white".</td>
+ </tr>
+
+ <tr>
+ <td><code>#direction</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#displayAlign</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. The initial value of <code>tts:displayAlign</code> <em title="SHALL" class="rfc2119">SHALL</em> be "after" for the default region, as defined in [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>].</td>
+ </tr>
+
+ <tr>
+ <td><code>#extent-region</code></td>
+
+ <td>
+ The <code>tts:extent</code> attribute when applied to a region element <em title="SHALL" class="rfc2119">SHALL</em> use <code>px</code> units or
+ "percentage" representation, and <em title="SHALL NOT" class="rfc2119">SHALL NOT</em> use <code>em</code> units.<br>
+ Section <a class="sec-ref" href="#layout-model"><span class="secno">7.2</span> <span class="sec-title">Layout Model</span></a> <em title="SHOULD" class="rfc2119">SHOULD</em> be used to calculate a region extent that avoids clipping.
+ </td>
+ </tr>
+
+ <tr>
+ <td><code>#fontFamily-generic</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. A <code>tts:fontFamily</code> of either "monospaceSerif" or
+ "proportionalSansSerif" <em title="SHOULD" class="rfc2119">SHOULD</em> be specified for all presented text content. A tts:fontFamily of
+ "default" <em title="SHALL" class="rfc2119">SHALL</em> be equivalent to "monospaceSerif".</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontFamily-non-generic</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontFamily</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontSize-anamorphic</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontSize-isomorphic</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontSize</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontStyle-italic</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontStyle-oblique</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontStyle</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontWeight-bold</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontWeight</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#image</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-em</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#lineBreak-uax14</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#lineHeight</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#nested-div</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#nested-span</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#origin</code></td>
+
+ <td>The <code>tts:origin</code> attribute <em title="SHALL" class="rfc2119">SHALL</em> use <code>px</code> units or "percentage" representation, and
+ <em title="SHALL NOT" class="rfc2119">SHALL NOT</em> use <code>em</code> units.</td>
+ </tr>
+
+ <tr>
+ <td><code>#padding-1</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#padding-2</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#padding-3</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#padding-4</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#padding</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textAlign-absolute</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textAlign-relative</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textAlign</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. The initial value of <code>tts:textAlign</code> <em title="SHALL" class="rfc2119">SHALL</em> be "center" for the default region, as defined in [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>].</td>
+ </tr>
+
+ <tr>
+ <td><code>#textDecoration-over</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textDecoration-through</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textDecoration-under</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textDecoration</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textOutline-blurred</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textOutline-unblurred</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textOutline</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. If specified, the border thickness <em title="SHALL" class="rfc2119">SHALL</em> be 10% or less than the associated font size.</td>
+ </tr>
+
+ <tr>
+ <td><code>#wrapOption</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#writingMode-vertical</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <div class="note"><div id="h_note_5" role="heading" aria-level="3" class="note-title"><span>Note</span></div><p class="">The initial values specified for <code>tts:color</code>, <code>tts:displayAlign</code> are those specified by [<cite><a href="#bib-ST2052-1" class="bibref">ST2052-1</a></cite>].</p></div>
+ </section>
+ </section>
+
+ <section id="image-profile-constraints">
+ <!--OddPage--><h2 id="h2_image-profile-constraints" role="heading" aria-level="1"><span class="secno">6. </span>Image Profile Constraints</h2>
+
+ <section id="profile-designator-and-definition-document-1">
+ <h3 id="h3_profile-designator-and-definition-document-1" role="heading" aria-level="2"><span class="secno">6.1 </span>Profile Designator and Definition Document</h3>
+
+ <div class="issue"><div id="h_issue_5" role="heading" aria-level="3" class="issue-title"><span>Issue 5</span></div><p class="">This Section is a placeholder and will be revisited based the outcome of the [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>] profile discussions.</p></div>
+
+ <p>A subtitle document conforming to the Image Profile <em title="SHALL" class="rfc2119">SHALL</em> be associated with the following profile designator and profile
+ definition document:</p>
+ <pre><?xml version="1.0" encoding="utf-8"?>
+<profile designator="http://www.w3.org/ns/ttml/profile/imsc/image/designator" xmlns="http://www.w3.org/ns/ttml#parameter">
+ <extensions>
+ <extension>http://www.w3.org/ns/ttml/profile/definition/imsc/image/feature#all</extension>
+ </extensions>
+</profile>
+</pre>
+ </section>
+
+ <section id="presented-image">
+ <h3 id="h3_presented-image" role="heading" aria-level="2"><span class="secno">6.2 </span>Presented Image</h3>
+
+ <section id="definition">
+ <h4 id="h4_definition" role="heading" aria-level="3"><span class="secno">6.2.1 </span>Definition</h4>
+
+ <p>A presented image <em title="SHALL" class="rfc2119">SHALL</em> be a <code>div</code> element with a smpte:backgroundImage attribute that is contained within a
+ presented region.</p>
+ </section>
+
+ <section id="number-per-region">
+ <h4 id="h4_number-per-region" role="heading" aria-level="3"><span class="secno">6.2.2 </span>Number per Region</h4><!-- start CFF-TT 1.0.7 -->
+
+ <p>In a given synchronic document, there shall be at most one presented image per presented region.</p>
+ <!-- end CFF-TT 1.0.7 -->
+ </section>
+ </section>
+
+ <section id="div-element">
+ <h3 id="h3_div-element" role="heading" aria-level="2"><span class="secno">6.3 </span><code>div</code> element</h3>
+
+ <p>If a <code>tts:backgroundImage</code> attribute is applied to a <code>div</code> element, the width and height of the
+ region extent associated with the <code>div</code> element <em title="SHALL" class="rfc2119">SHALL</em> be present and <em title="SHALL" class="rfc2119">SHALL</em> be equal to the width and height of the
+ image source referenced by the <code>tts:backgroundImage</code>.</p>
+ </section>
+
+ <section id="features-2">
+ <h3 id="h3_features-2" role="heading" aria-level="2"><span class="secno">6.4 </span>Features</h3>
+
+ <div class="issue"><div id="h_issue_6" role="heading" aria-level="3" class="issue-title"><span>Issue 6</span></div><p class="">The following assumes, but does not require, the porting of the [<cite><a href="#bib-ST2052-1" class="bibref">ST2052-1</a></cite>] <code>#backgroundImage</code>
+ features to [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>]. See <a href="http://www.w3.org/AudioVideo/TT/tracker/issues/238">ISSUE-238</a>.</p></div>
+
+
+ <p>The features included in a subtitle document <em title="SHALL" class="rfc2119">SHALL</em> conform to the Table below:</p>
+
+ <table class="simple">
+ <thead>
+ <tr>
+ <th>Feature</th>
+
+ <th>Provisions</th>
+ </tr>
+ </thead>
+
+ <tbody>
+ <tr>
+ <td><code>#backgroundImage</code></td>
+
+ <td><em title="MAY" class="rfc2119">MAY</em> be used. The backgroundImage attribute <em title="SHALL" class="rfc2119">SHALL</em> reference a complete image that conforms to the PNG image coding
+ as specified in Sections 7.1.1.3 and 15.1 of [<cite><a href="#bib-MHP" class="bibref">MHP</a></cite>].<br>
+ If a pHYs chunk is present, it <em title="SHALL" class="rfc2119">SHALL</em> indicate square pixels. Note: If no pixel aspect ratio is carried, the default of
+ square pixels will be assumed.</td>
+ </tr>
+
+ <tr>
+ <td><code>#backgroundImageHorizontal</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used. <code>#backgroundImage</code> remains available for use.</td>
+ </tr>
+
+ <tr>
+ <td><code>#backgroundImageVertical</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used. <code>#backgroundImage</code> remains available for use.</td>
+ </tr>
+
+ <tr>
+ <td><code>#bidi</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#color</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#content</code></td>
+
+ <td>The <code>p</code>, <code>span</code> and <code>br</code> elements <em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be present.</td>
+ </tr>
+
+ <tr>
+ <td><code>#direction</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#displayAlign</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontFamily</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontSize</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontStyle</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#fontWeight</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#image</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#length-em</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#lineBreak-uax14</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#lineHeight</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#nested-div</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#nested-span</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#padding</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textAlign</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textDecoration</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#textOutline</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#wrapOption</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+
+ <tr>
+ <td><code>#writingMode-vertical</code></td>
+
+ <td><em title="SHALL NOT" class="rfc2119">SHALL NOT</em> be used.</td>
+ </tr>
+ </tbody>
+ </table>
+ </section>
+ </section>
+
+ <section id="hypothetical-render-model-1">
+ <!--OddPage--><h2 id="h2_hypothetical-render-model-1" role="heading" aria-level="1"><span class="secno">7. </span>Hypothetical Render Model</h2>
+
+ <section id="performance-model">
+ <h3 id="h3_performance-model" role="heading" aria-level="2"><span class="secno">7.1 </span>Performance Model</h3>
+
+ <section id="overview">
+ <h4 id="h4_overview" role="heading" aria-level="3"><span class="secno">7.1.1 </span>Overview</h4>
+
+ <p>This Section specifies the Hypothetical Render Model illustrated in <a class="fig-ref" href="#fig-hypothetical-render-model">Fig. <span class="figno">1</span> <span class="fig-title">
+ Hypothetical Render Model
+ </span></a>.</p>
+
+ <p>The purpose of the model is to limit subtitle document complexity. It is not however intended to serve as basis for
+ implementation. For instance, while the model defines a glyph buffer for the purpose of limiting the number of glyphs
+ displayed at any given point in time, it does not require an implementation to implement such a buffer.</p>
+
+ <figure id="fig-hypothetical-render-model">
+ <img src="hypothetical-render-figure-1.png" alt="Hypothetical Render Model">
+
+ <figcaption>Fig. <span class="figno">1</span> <span class="fig-title">
+ Hypothetical Render Model
+ </span></figcaption>
+ </figure>
+
+ <p>The model operates on successive intermediate synchronic documents obtained from an input subtitle document, and uses a
+ simple double buffering model: while an intermediate synchronic document E<sub>n</sub> is being painted into Presentation
+ Buffer P<sub>n</sub> (the "front buffer" of the model), the previous intermediate synchronic document
+ E<sub>n-1</sub> is available for display in Presentation Buffer P<sub>n-1</sub> (the "back buffer" of the
+ model).</p>
+
+ <p>The model specifies an (hypothetical) time required for completely painting an intermediate synchronic document as a
+ proxy for complexity. Painting includes drawing region backgrounds, rendering and copying glyphs, and decoding and copying
+ images. Complexity is then limited by requiring that painting of intermediate synchronic document E<sub>n</sub> completes
+ before the end of intermediate synchronic document E<sub>n-1</sub>.</p>
+
+ <p>Whenever applicable, constraints are specified relative to root container dimensions, allowing subtitle sequences to be
+ authored independently of related video object resolution.</p>
+
+ <p>To enables scenarios where the same glyphs are used in multiple successive intermediate synchronic documents, e.g. to
+ convey a CEA-608/708-style roll-up (see [<cite><a href="#bib-CEA-608" class="bibref">CEA-608</a></cite>] and [<cite><a href="#bib-CEA-708" class="bibref">CEA-708</a></cite>]), the Glyph Buffers G<sub>n</sub> and G<sub>n-1</sub>
+ store rendered glyphs across intermediate synchronic documents, allowing glyphs to be copied into the Presentation Buffer
+ instead of rendered, a more costly operation.</p>
+
+ <p>Similarly, Decoded Image Buffers D<sub>n</sub> and D<sub>n-1</sub> store decoded images across intermediate synchronic
+ documents, allowing images to be copied into the Presentation Buffer instead of decoded.</p>
+ </section>
+
+ <section id="general-2">
+ <h4 id="h4_general-2" role="heading" aria-level="3"><span class="secno">7.1.2 </span>General</h4>
+
+ <p>The Presentation Compositor <em title="SHALL" class="rfc2119">SHALL</em> render in Presentation Buffer P<sub>n</sub> each successive intermediate synchronic
+ document E<sub>n</sub> using the following steps in order:</p>
+
+ <ol>
+ <li>clear the pixels, except for the first intermediate synchronic document E<sub>0</sub> for the which the pixels of
+ P<sub>0</sub> <em title="SHALL" class="rfc2119">SHALL</em> be assumed to have been cleared;</li>
+
+ <li>paint, according to stacking order, all background pixels for each region;</li>
+
+ <li>paint all pixels for background colors associated with text or image subtitle content; and</li>
+
+ <li>paint the text or image subtitle content.</li>
+ </ol>
+
+ <p>The Presentation Compositor <em title="SHALL" class="rfc2119">SHALL</em> start rendering E<sub>n</sub>:</p>
+
+ <ul>
+ <li>at the presentation time of E<sub>0</sub> minus Initial Painting Delay (IPD), if n = 0</li>
+
+ <li>at the presentation time of E<sub>n-1</sub>, if n > 0</li>
+ </ul>
+
+ <p>The duration DUR(E<sub>n</sub>) for painting an intermediate synchronic document E<sub>n</sub> in the Presentation
+ Buffer P<sub>n</sub> <em title="SHALL" class="rfc2119">SHALL</em> be:</p>
+
+ <p>DUR(E<sub>n</sub>) = S(E<sub>n</sub>) / BDraw + DUR<sub>T</sub>(E<sub>n</sub>) + DUR<sub>I</sub>(E<sub>n</sub>)</p>
+
+ <p>Where:</p>
+
+ <ul>
+ <li>S(E<sub>n</sub>) is the total normalized drawing area for intermediate synchronic document E<sub>n</sub>, as
+ specified in <a class="sec-ref" href="#paint-regions"><span class="secno">7.1.3</span> <span class="sec-title">Paint Regions</span></a>
+ </li>
+
+ <li>BDraw is the normalized background drawing performance factor.</li>
+
+ <li>DUR<sub>T</sub>(E<sub>n</sub>) is the duration, in seconds, for painting the text subtitle content for intermediate
+ synchronic document E<sub>n</sub>, as specified in Section <a class="sec-ref" href="#paint-text"><span class="secno">7.1.5</span> <span class="sec-title">Paint Text</span></a>
+ </li>
+
+ <li>DUR<sub>I</sub>(E<sub>n</sub>) is the duration, in seconds, for painting the image subtitle content for intermediate
+ synchronic document E<sub>n</sub>, as specified in Section <a class="sec-ref" href="#paint-images"><span class="secno">7.1.4</span> <span class="sec-title">Paint Images</span></a>
+ </li>
+ </ul>
+
+ <p>The contents of the Presentation Buffer P<sub>n</sub> <em title="SHALL" class="rfc2119">SHALL</em> be transferred instantaneously to Presentation Buffer
+ P<sub>n-1</sub> at the presentation time of intermediate synchronic document E<sub>n</sub>, making the latter available for
+ display.</p>
+
+ <div class="note"><div id="h_note_6" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">It is possible for the contents of Presentation Buffer P<sub>n-1</sub> to never be displayed. This can
+ happen if Presentation Buffer P<sub>n</sub> is copied twice to Presentation Buffer P<sub>n-1</sub> between two consecutive
+ video frame boundaries of the related video object.</p></div>
+
+ <p>It <em title="SHALL" class="rfc2119">SHALL</em> be an error for the Presentation Compositor to fail to complete painting pixels for E<sub>n</sub> before the
+ presentation time of E<sub>n</sub>.</p>
+
+ <p>Unless specified otherwise, the following table <em title="SHALL" class="rfc2119">SHALL</em> specify values for IPD and BDraw.</p>
+
+ <table class="simple">
+ <thead>
+ <tr>
+ <th>Parameter</th>
+
+ <th>Initial value</th>
+ </tr>
+ </thead>
+
+ <tbody>
+ <tr>
+ <td>Initial Painting Delay (IPD)</td>
+
+ <td>1 s</td>
+ </tr>
+
+ <tr>
+ <td>Normalized background drawing performance factor (BDraw)</td>
+
+ <td>12 s<sup>-1</sup></td>
+ </tr>
+ </tbody>
+ </table>
+
+ <div class="note"><div id="h_note_7" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">BDraw effectively sets a limit on fillings regions - for example, assuming that the root container is
+ ultimately rendered at 1920×1080 resolution, a BDraw of 12 s<sup>-1</sup> would correspond to a fill rate of
+ 1920×1080×12/s=23.7×2<sup>20</sup>pixels s<sup>-1</sup>.</p></div>
+
+ <div class="note"><div id="h_note_8" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">IPD effectively sets a limit on the complexity of any given intermediate synchronic document.</p></div>
+ </section>
+
+ <section id="paint-regions">
+ <h4 id="h4_paint-regions" role="heading" aria-level="3"><span class="secno">7.1.3 </span>Paint Regions</h4>
+
+ <p>The total normalized drawing area S(E<sub>n</sub>) for intermediate synchronic document E<sub>n</sub> <em title="SHALL" class="rfc2119">SHALL</em> be</p>
+
+ <p>S(E<sub>n</sub>) = CLEAR(E<sub>n</sub>) + PAINT(E<sub>n</sub> )</p>
+
+ <p>where CLEAR(E<sub>0</sub>) = 0 and CLEAR(E<sub>n | n > 0</sub>) = 1, i.e. the root container in its entirety.</p>
+
+ <div class="note"><div id="h_note_9" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">To ensure consistency of the Presentation Buffer, a new intermediate synchronic document requires clearing
+ of the root container.</p></div>
+
+ <p>PAINT(E<sub>n</sub>) <em title="SHALL" class="rfc2119">SHALL</em> be the normalized area to be painted for all regions that are used in intermediate synchronic
+ document E<sub>n</sub> according to</p>
+
+ <p>PAINT(E<sub>n</sub>) = ∑<sub>R<sub>i</sub>∈R<sub>p</sub></sub> SIZE(R<sub>i</sub>) ∙ NBG(R<sub>i</sub>)</p>
+
+ <p>where R_p <em title="SHALL" class="rfc2119">SHALL</em> be the set of regions presented in the intermediate synchronic document E<sub>n</sub> – see Section
+ <a class="sec-ref" href="#presented-region"><span class="secno">4.5.1</span> <span class="sec-title">Presented Region</span></a> for the definition of presented region.</p>
+
+ <p>NSIZE(R<sub>i</sub>) <em title="SHALL" class="rfc2119">SHALL</em> be given by:</p>
+
+ <p>NSIZE(R<sub>i</sub>) = (width of R<sub>i</sub> ∙ height of R<sub>i</sub> ) ÷ (root container height ∙ root
+ container width)</p>
+
+ <aside class="example"><div class="example-title"><span>Example 2</span></div>
+ For a region R<sub>i</sub> in with <code>tts:extent="250px 50px"</code> within a root container with
+ <code>tts:extent="1920px 1080px"</code>, NSIZE(R<sub>i</sub>) = 0.603.
+ </aside>
+
+ <p>NBG(R<sub>i</sub>) <em title="SHALL" class="rfc2119">SHALL</em> be the total number of <code>tts:backgroundColor</code> attributes associated with the given
+ region R<sub>i</sub> in the intermediate synchronic document. A <code>tts:backgroundColor</code> attribute is associated
+ with a region when it is explicitly specified (either as an attribute in the element, or by reference to a declared style)
+ in the following circumstances:</p>
+
+ <ul>
+ <li>It is specified on the <code>region</code> layout element that defines the region.</li>
+
+ <li>It is specified on a <code>div</code>, <code>p</code>, <code>span</code> or <code>br</code> content element that is
+ to be flowed into the region for presentation in the intermediate synchronic document (see [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>] for more details on
+ when a content element is followed into a region).</li>
+
+ <li>It is specified on a <code>set</code> animation element that is to be applied to content elements that are to be
+ flowed into the region for presentation in the intermediate synchronic document (see [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>] for more details on when
+ a <code>set</code> animation element is applied to content elements).</li>
+ </ul>
+
+ <p>Even if a specified <code>tts:backgroundColor</code> is the same as specified on the nearest ancestor content element or
+ animation element, specifying any <code>tts:backgroundColor</code> <em title="SHALL" class="rfc2119">SHALL</em> require an additional fill operation for all
+ region pixels.</p>
+ </section>
+
+ <section id="paint-images">
+ <h4 id="h4_paint-images" role="heading" aria-level="3"><span class="secno">7.1.4 </span>Paint Images</h4>
+
+ <p>The Presentation Compositor <em title="SHALL" class="rfc2119">SHALL</em> paint into the Presentation Buffer P<sub>n</sub> all visible pixels of presented
+ images of intermediate synchronic document E<sub>n</sub>.</p>
+
+ <p>For each presented image, the Presentation Compositor <em title="SHALL" class="rfc2119">SHALL</em> either:</p>
+
+ <ul>
+ <li>if an identical image is present in Decoded Image Buffer D<sub>n</sub>, copy the image from Decoded Image Buffer
+ D<sub>n</sub> to the Presentation Buffer P<sub>n</sub> using the Image Copier; or</li>
+
+ <li>if an identical image is present in Decoded Image Buffer D<sub>n-1</sub>, i.e. an identical image was present in
+ intermediate synchronic document E<sub>n-1</sub>, copy using the Image Copier the glyph from Decoded Image Buffer
+ D<sub>n-1</sub> to both the Decoded Image Buffer D<sub>n</sub> and the Presentation Buffer P<sub>n</sub>; or</li>
+
+ <li>Otherwise, decode the image using the Image Decoder the image into the Presentation Buffer P<sub>n</sub> and Decoded
+ Image Buffer D<sub>n</sub>.</li>
+ </ul>
+
+ <p>Two images <em title="SHALL" class="rfc2119">SHALL</em> be identical if and only if they reference the same encoded image source.</p>
+
+ <p>The duration DUR<sub>I</sub>(E<sub>n</sub>) for painting images of an intermediate synchronic document E<sub>n</sub> in
+ the Presentation Buffer <em title="SHALL" class="rfc2119">SHALL</em> be as follows:</p>
+
+ <p>DUR<sub>I</sub>(E<sub>n</sub>) = ∑<sub>I<sub>i</sub> ∈ I<sub>c</sub></sub> NRGA(I<sub>i</sub>) / ICpy +
+ ∑<sub>I<sub>j</sub> ∈ I<sub>d</sub></sub> NSIZ(I<sub>j</sub>) / IDec</p>
+
+ <p>where</p>
+
+ <ul>
+ <li>I<sub>c</sub> is the set of images copied when painting intermediate synchronic document E<sub>n</sub></li>
+
+ <li>I<sub>d</sub> is the set of images decoded when painting intermediate synchronic document E<sub>n</sub></li>
+
+ <li>IDec is the image decoding rate</li>
+
+ <li>ICpy is the normalized image copy performance factor.</li>
+ </ul>
+
+ <p>NRGA(I<sub>i</sub>) is the Normalized Image Area of presented image I<sub>i</sub> and <em title="SHALL" class="rfc2119">SHALL</em> be equal to:</p>
+
+ <p>NRGA(I<sub>i</sub>)= (width of I<sub>i</sub> ) ∙ height of I<sub>i</sub> ) ÷ ( root container height ∙ root
+ container width )</p>
+
+ <p>NSIZ(I<sub>i</sub>) <em title="SHALL" class="rfc2119">SHALL</em> be the number of pixels of presented image I<sub>i</sub>.</p>
+
+ <p>The contents of the Decoded Image Buffer D<sub>n</sub> <em title="SHALL" class="rfc2119">SHALL</em> be transferred instantaneously to Decoded Image Buffer
+ D<sub>n-1</sub> at the presentation time of intermediate synchronic document E<sub>n</sub>.</p>
+
+ <p>The total size occupied by images stored in Decoded Image Buffers D<sub>n</sub> or D<sub>n-1</sub> <em title="SHALL" class="rfc2119">SHALL</em> be the sum of
+ their Normalized Image Area.</p>
+
+ <p>The size of Decoded Image Buffers D<sub>n</sub> or D<sub>n-1</sub> <em title="SHALL" class="rfc2119">SHALL</em> be the Normalized Decoded Image Buffer Size
+ (NDIBS).</p>
+
+ <p>Unless specified otherwise, the following table <em title="SHALL" class="rfc2119">SHALL</em> specify ICpy, Idec, and NDBIS.</p>
+
+ <table class="simple">
+ <thead>
+ <tr>
+ <th>Parameter</th>
+
+ <th>Initial value</th>
+ </tr>
+ </thead>
+
+ <tbody>
+ <tr>
+ <td>Normalized image copy performance factor (ICpy)</td>
+
+ <td>6</td>
+ </tr>
+
+ <tr>
+ <td>Image Decoding rate (Idec)</td>
+
+ <td>1 × 2<sup>20</sup> pixels s<sup>-1</sup></td>
+ </tr>
+
+ <tr>
+ <td>Normalized Decoded Image Buffer Size (NDIBS)</td>
+
+ <td>0.9885</td>
+ </tr>
+ </tbody>
+ </table>
+ </section>
+
+ <section id="paint-text">
+ <h4 id="h4_paint-text" role="heading" aria-level="3"><span class="secno">7.1.5 </span>Paint Text</h4>
+
+ <p>For each glyph displayed in intermediate synchronic document E<sub>n</sub>, the Presentation Compositor <em title="SHALL" class="rfc2119">SHALL</em>:</p>
+
+ <ul>
+ <li>if an identical glyph is present in Glyph Buffer G<sub>n</sub>, copy the glyph from Glyph Buffer G<sub>n</sub> to the
+ Presentation Buffer P<sub>n</sub> using the Glyph Copier; or</li>
+
+ <li>if an identical glyph is present in Glyph Buffer G<sub>n-1</sub>, i.e. an identical glyph was present in intermediate
+ synchronic document E<sub>n-1</sub>, copy using the Glyph Copier the glyph from Glyph Buffer G<sub>n-1</sub> to both the
+ Glyph Buffer G<sub>n</sub> and the Presentation Buffer P<sub>n</sub>; or</li>
+
+ <li>Otherwise render using the Glyph Renderer the glyph into the Presentation Buffer P<sub>n</sub> and Glyph Buffer
+ G<sub>n</sub> using the corresponding style information.</li>
+ </ul>
+
+ <p>Two glyphs are identical if and only if the following [<cite><a href="#bib-TTML2" class="bibref">TTML2</a></cite>] styles are identical:</p>
+
+ <ul>
+ <li><code>tts:color</code></li>
+
+ <li><code>tts:fontFamily</code></li>
+
+ <li><code>tts:fontSize</code></li>
+
+ <li><code>tts:fontStyle</code></li>
+
+ <li><code>tts:fontWeight</code></li>
+
+ <li><code>tts:textDecoration</code></li>
+
+ <li><code>tts:textOutline</code></li>
+ </ul>
+
+ <figure id="fig-example-of-presentation-compositor-behavior-for-text-rendering">
+ <img src="text-render-example-figure-2.png" alt="Example of Presentation Compositor Behavior for Text Rendering" height="150" width="324">
+
+ <figcaption>Fig. <span class="figno">2</span> <span class="fig-title">
+ Example of Presentation Compositor Behavior for Text Rendering
+ </span></figcaption>
+ </figure>
+
+ <p>The duration DUR<sub>T</sub>(E<sub>n</sub>) for painting the text of an intermediate synchronic document E<sub>n</sub>
+ in the Presentation Buffer is as follows:</p>
+
+ <p>DUR<sub>T</sub>(E<sub>n</sub>) = ∑<sub>G<sub>i</sub> ∈ G<sub>r</sub></sub> NRGA(G<sub>i</sub>) / Ren(G<sub>i</sub>)
+ + ∑<sub>G<sub>j</sub> ∈ G<sub>c</sub></sub> NRGA(G<sub>j</sub>) / GCpy</p>
+
+ <p>Where:</p>
+
+ <ul>
+ <li>G<sub>r</sub> is the set of glyphs rendered into the Presentation Buffer P<sub>n</sub> using the Glyph Renderer in
+ intermediate synchronic document E<sub>n</sub>.</li>
+
+ <li>G<sub>c</sub> is the set of glyphs copied to the Presentation Buffer P<sub>n</sub> using the Glyph Copier in
+ intermediate synchronic document E<sub>n</sub>.</li>
+
+ <li>Ren(G<sub>i</sub>) is the text rendering performance factor glyph G<sub>i</sub></li>
+
+ <li>GCpy is the normalized glyph copy performance factor</li>
+ </ul>
+
+ <p>G<sub>r</sub> and G<sub>c</sub> <em title="SHALL" class="rfc2119">SHALL</em> include only glyphs in presented regions and <em title="SHALL NOT" class="rfc2119">SHALL NOT</em> include a [<cite><a href="#bib-UNICODE" class="bibref">UNICODE</a></cite>] Code
+ Point if it does not result in a change to presentation, e.g. the Code Point is ignored.</p>
+
+ <p>The Normalized Rendered Glyph Area NRGA(G<sub>i</sub>) of a glyph G<sub>i</sub> <em title="SHALL" class="rfc2119">SHALL</em> be equal to:</p>
+
+ <p>NRGA(G<sub>i</sub>)= (fontSize of G<sub>i</sub> as percentage of root container height)<sup>2</sup></p>
+
+ <p>The contents of the Glyph Buffer G<sub>n</sub> <em title="SHALL" class="rfc2119">SHALL</em> be copied instantaneously to Glyph Buffer G<sub>n-1</sub> at the
+ presentation time of intermediate synchronic document E<sub>n</sub>.</p>
+
+ <p>The total size occupied by the glyphs stored in Glyph Buffers G<sub>n</sub> or G<sub>n-1</sub> <em title="SHALL" class="rfc2119">SHALL</em> be the sum of their
+ Normalized Rendered Glyph Area.</p>
+
+ <p>The size of Glyph Buffers G<sub>n</sub> and G<sub>n-1</sub> <em title="SHALL" class="rfc2119">SHALL</em> be the Normalized Glyph Buffer Size (NGBS).</p>
+
+ <p>Unless specified otherwise, the following table <em title="SHALL" class="rfc2119">SHALL</em> specify GCpy, Ren and NGBS, and <em title="SHALL" class="rfc2119">SHALL</em> apply to all supported font
+ styles (including provision of outline border).</p>
+
+ <table class="simple">
+ <thead>
+ <tr>
+ <th>Parameter</th>
+
+ <th>Initial value</th>
+ </tr>
+ </thead>
+
+ <tbody>
+ <tr>
+ <td>Normalized glyph copy performance factor (GCpy)</td>
+
+ <td>12</td>
+ </tr>
+
+ <tr>
+ <td>Text rendering performance factor Ren(G<sub>i</sub> if G<sub>i</sub> is not a CJK Unified Ideograph as specified
+ in [<cite><a href="#bib-UNICODE" class="bibref">UNICODE</a></cite>].</td>
+
+ <td>1.2</td>
+ </tr>
+
+ <tr>
+ <td>Text rendering performance factor Ren(G<sub>i</sub>) if G<sub>i</sub> is a CJK Unified Ideograph as specified in
+ [<cite><a href="#bib-UNICODE" class="bibref">UNICODE</a></cite>].</td>
+
+ <td>0.6</td>
+ </tr>
+
+ <tr>
+ <td>Normalized Glyph Buffer Size (NGBS)</td>
+
+ <td>1</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <div class="note"><div id="h_note_10" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">NRGA(G<sub>i</sub>) does not take into account glyph decorations (e.g. underline), glyph effects (e.g.
+ outline) or actual glyph aspect ratio. An implementation can determine an actual buffer size needs based on worst-case
+ glyph size complexity.</p></div>
+
+ <aside class="example"><div class="example-title"><span>Example 3</span></div>
+ Setting a Glyph Buffer Normalized Size effectively sets a limit on the total number of distinct glyphs present in any
+ given intermediate synchronic document E<sub>n</sub>. For example, assuming a maximum Normalized Glyph Buffer Size of 1
+ and the default tts:fontSize of 1c are used, the glyph's height as percentage of root container height is 1/15 , and
+ the maximum number of distinct glyphs that can be buffered is 1÷(1÷15)^2=225 glyphs. In this example, an implementation
+ rendering at 1920x1080 would need to allocate a glyph buffer no smaller than (1920÷32)×(1080÷15)×225=~1 Mpixels.
+ </aside>
+
+ <aside class="example"><div class="example-title"><span>Example 4</span></div>
+ GCpy effectively sets a limit on animating glyphs. For example, assuming that the root container is ultimately rendered
+ at 1920×1080 resolution and no regions need to have background color painted (so only a CLEAR(E<sub>n</sub>) operation
+ is required for the normalized drawing area for the intermediate synchronic document), a GCpy and BDraw of 12 s-1 would
+ mean that a group of 160 glyphs with a tts:fontSize equal to 5% of the root container height could be moved at most
+ approximately 12 s<sup>-1</sup> ÷ (1 + ( 160 × 0.05<sup>2</sup> )) = 8.6 times per second.
+ </aside>
+
+ <aside class="example"><div class="example-title"><span>Example 5</span></div>
+ Ren(G<sub>i</sub>) effectively sets a limit on the glyph rendering rate. For example, assuming that the root container is
+ ultimately rendered at a 1920×1080 resolution, a Ren(G<sub>i</sub>) of 1.2 s-1 would mean that at most 120 glyphs with a
+ fontSize of 108 px (10% of 1080 px and NRGA(G<sub>i</sub>) = 0.01) could be rendered every second.
+ </aside>
+ </section>
+ </section><!-- start CFF-TT 1.0.7 -->
+
+ <section id="layout-model">
+ <h3 id="h3_layout-model" role="heading" aria-level="2"><span class="secno">7.2 </span>Layout Model</h3>
+
+ <section id="general-3">
+ <h4 id="h4_general-3" role="heading" aria-level="3"><span class="secno">7.2.1 </span>General</h4>
+
+ <p>The height and width of the area occupied by text within a region depend on line height as well as the width of, and
+ spacing between (kerning), individual glyphs. The following allows the area occupied by text to be precisely determined,
+ and thus region extent to be set such that text flows without clipping.</p>
+ </section>
+
+ <section id="reference-fonts">
+ <h4 id="h4_reference-fonts" role="heading" aria-level="3"><span class="secno">7.2.2 </span>Reference Fonts</h4>
+
+ <p>A glyph that matches one of the combinations of computed font family and code point listed in the table below <em title="SHALL" class="rfc2119">SHALL</em> be laid out using metrics equal to the metrics of the specified reference font, unless the glyph is not defined by the
+ reference font.</p>
+
+ <table class="simple">
+ <thead>
+ <tr>
+ <th>Computed Font Family</th>
+
+ <th>Code Points</th>
+
+ <th>Reference Font</th>
+ </tr>
+ </thead>
+
+ <tbody>
+ <tr>
+ <td>monospaceSerif</td>
+
+ <td>
+ All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>
+ </td>
+
+ <td>
+ <a href="http://www.microsoft.com/typography/fonts/family.aspx?FID=10">http://www.microsoft.com/typography/fonts/family.aspx?FID=10</a>
+ (Courier New)
+ </td>
+ </tr>
+
+ <tr>
+ <td>proportionalSansSerif</td>
+
+ <td>
+ All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>, excluding the code
+ points defined for Semitic languages alone.
+ </td>
+
+ <td>
+ <a href="http://www.microsoft.com/typography/fonts/family.aspx?FID=8">http://www.microsoft.com/typography/fonts/family.aspx?FID=8</a>
+ (Arial) or <a href="http://www.linotype.com/en/526/Helvetica-family.html">http://www.linotype.com/en/526/Helvetica-family.html</a>
+ (Helvetica)
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <div class="note"><div id="h_note_11" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">Implementations can use use fonts other than those specified above. Two fonts with equal metrics can have a
+ different appearance, but flow identically.</p></div>
+
+ <div class="note"><div id="h_note_12" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">proportionalSansSerif is not used in practice for Hebrew and Arabic captions and subtitles.</p></div>
+ </section>
+
+ <section id="line-height-and-centering">
+ <h4 id="h4_line-height-and-centering" role="heading" aria-level="3"><span class="secno">7.2.3 </span>Line Height and Centering</h4>
+
+ <p>The computed value of <code>tts:lineHeight</code> shall be equal to 120% if tts:lineHeight="normal".</p>
+
+ <p><code>tts:lineHeight</code> values expressed using the percentage metric shall be relative to the largest font size on
+ the line.</p>
+
+ <aside class="example"><div class="example-title"><span>Example 6</span></div>
+ Assuming that the root container is ultimately rendered at a 1920×1080 resolution and
+ <code>tts:lineHeight</code>="100%", a line mixing glyphs with font size of "10px", "36px"
+ and "1c" has a computed value of <code>tts:lineHeight</code> equal to "72px".
+ </aside>
+
+ <p>If the computed value of <code>tts:lineHeight</code> is not supported, then a presentation processor <em title="SHALL" class="rfc2119">SHALL</em> use the next
+ highest supported value.</p>
+
+ <aside class="example"><div class="example-title"><span>Example 7</span></div>
+ Three lines of 12px characters with <code>tts:lineHeight</code>="normal" has a height of 45px = ⌈12px *
+ 120%⌉ × 3 assuming line heights have 1px resolution.
+ </aside>
+
+ <p>White space in excess of the largest font size on the line <em title="SHALL" class="rfc2119">SHALL</em> be allocated evenly top and bottom (half-leading). Note
+ that inter-baseline separation includes any leading.</p><!-- end CFF-TT 1.0.7 -->
+
+ <div class="note"><div id="h_note_13" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">Since font size can change on a line and text can wrap, it is necessary to first determine the glyphs
+ present on a line before determining line height.</p></div>
+
+ <div class="note"><div id="h_note_14" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="">Glyphs that do not extend beyond the specific <code>tts:fontSize</code> value will not clip top or
+ bottom.</p></div>
+ </section>
+ </section>
+ </section>
+
+ <section id="recommended-character-sets-1" class="appendix">
+ <!--OddPage--><h2 id="h2_recommended-character-sets-1" role="heading" aria-level="1"><span class="secno">A. </span>Recommended Character Sets</h2>
+
+
+ <p>When authoring textual content, authors are encouraged to select from sets of characters based on the language expressed using the xml:lang. The idea is to increase the confidence that the text will be presented correctly by implementations targeting specific locales.</p>
+
+ <p>Specifically, for a given language X, an author should choose characters from the set resulting from the union of the following sets:
+ </p><li>the main basic exemplar character set specified for the language in [<cite><a href="#bib-CLDR" class="bibref">CLDR</a></cite>]; and</li>
+ <li>the common character set specified in Table 1; and</li>
+ <li>supplementary characters specified for the language in Table 2, if any</li>
+
+ <p></p>
+
+<p>In other words, the character set specified in Table XXXX is available to authors across all languages, and Table XXXX specifies characters that have proven useful in captioning and subtitling applications for a given language. Some of these sets may overlap.</p>
+
+ <p>The terms used in this table are defined in [<cite><a href="#bib-UNICODE" class="bibref">UNICODE</a></cite>].</p>
+
+ <table class="simple">
+ <caption>Table 1. Common Character Set.</caption>
+ <tbody><tr>
+ <th>(Basic Latin)</th>
+ </tr>
+
+ <tr>
+ <td>U+0020 - U+007E (Letterlike Symbols)</td>
+ </tr>
+
+ <tr>
+ <td>U+2103 : DEGREES CELSIUS</td>
+ </tr>
+
+ <tr>
+ <td>U+2109 : DEGREES FAHRENHEIT</td>
+ </tr>
+
+ <tr>
+ <td>U+2120 : SERVICE MARK SIGN</td>
+ </tr>
+
+ <tr>
+ <td>U+2122 : TRADE MARK SIGN</td>
+ </tr>
+
+ <tr>
+ <th>(Latin-1 Supplement)</th>
+ </tr>
+
+ <tr>
+ <td>U+00A0 - U+00FF</td>
+ </tr>
+
+ <tr>
+ <th>(Number Forms)</th>
+ </tr>
+
+ <tr>
+ <td>U+2153 – U+215F : Fractions</td>
+ </tr>
+
+ <tr>
+ <th>(Latin Extended-A)</th>
+ </tr>
+
+ <tr>
+ <td>U+0152 : LATIN CAPITAL LIGATURE OE</td>
+ </tr>
+
+ <tr>
+ <td>U+0153 : LATIN SMALL LIGATURE OE</td>
+ </tr>
+
+ <tr>
+ <td>U+0160 : LATIN CAPITAL LETTER S WITH CARON</td>
+ </tr>
+
+ <tr>
+ <td>U+0161 : LATIN SMALL LETTER S WITH CARON</td>
+ </tr>
+
+ <tr>
+ <td>U+0178 : LATIN CAPITAL LETTER Y WITH DIAERESIS</td>
+ </tr>
+
+ <tr>
+ <td>U+017D : LATIN CAPITAL LETTER Z WITH CARON</td>
+ </tr>
+
+ <tr>
+ <td>U+017E : LATIN SMALL LETTER Z WITH CARON</td>
+ </tr>
+
+ <tr>
+ <th>(Box Drawing)</th>
+ </tr>
+
+ <tr>
+ <td>U+2500 : BOX DRAWINGS LIGHT HORIZONTAL</td>
+ </tr>
+
+ <tr>
+ <td>U+2502 : BOX DRAWINGS LIGHT VERTICAL</td>
+ </tr>
+
+ <tr>
+ <td>U+250C : BOX DRAWINGS LIGHT DOWN AND RIGHT</td>
+ </tr>
+
+ <tr>
+ <td>U+2510 : BOX DRAWINGS LIGHT DOWN AND LEFT</td>
+ </tr>
+
+ <tr>
+ <td>U+2514 : BOX DRAWINGS LIGHT UP AND RIGHT</td>
+ </tr>
+
+ <tr>
+ <td>U+2518 : BOX DRAWINGS LIGHT UP AND LEFT</td>
+ </tr>
+
+ <tr>
+ <th>(Latin Extended-B)</th>
+ </tr>
+
+ <tr>
+ <td>U+0192 : LATIN SMALL LETTER F WITH HOOK</td>
+ </tr>
+
+ <tr>
+ <th>(Block Elements)</th>
+ </tr>
+
+ <tr>
+ <td>U+2588 : FULL BLOCK</td>
+ </tr>
+
+ <tr>
+ <th>(Spacing Modifier Letters)</th>
+ </tr>
+
+ <tr>
+ <td>U+02DC : SMALL TILDE</td>
+ </tr>
+ <tr>
+ <th>(Geometric Shapes)</th>
+ </tr>
+
+ <tr>
+ <td>U+25A1 : WHITE SQUARE</td>
+ </tr>
+
+ <tr>
+ <th>(General Punctuation)</th>
+ </tr>
+
+ <tr>
+ <td>U+2010 - U+2015 : Dashes</td>
+ </tr>
+
+ <tr>
+ <td>U+2016 - U+2027 : General punctuation</td>
+ </tr>
+
+ <tr>
+ <td>U+2030 - U+203A : General punctuation</td>
+ </tr>
+
+ <tr>
+ <th>(Musical Symbols)</th>
+ </tr>
+
+ <tr>
+ <td>U+2669 : QUARTER NOTE</td>
+ </tr>
+
+ <tr>
+ <td>U+266A : EIGHTH NOTE</td>
+ </tr>
+
+ <tr>
+ <td>U+266B : BEAMED EIGHTH NOTES</td>
+ </tr>
+
+ <tr>
+ <th>(Currency symbols)</th>
+ </tr>
+
+ <tr>
+ <td>U+20AC : EURO SIGN</td>
+ </tr>
+ </tbody></table>
+
+ <table class="simple">
+ <caption>Table 2. Supplementary Character Sets.</caption>
+ <thead>
+ <tr>
+
+ <th>Primary language subtag</th>
+
+ <th>Characters</th>
+ </tr>
+ </thead>
+
+ <tbody>
+
+
+ <tr>
+
+ <td>lv, lt, et, tr, hr, cs, pl, sl, sk</td>
+
+ <td>
+ (Latin Extended-A)<br>
+ U+0100 – U+017F</td>
+ </tr>
+
+ <tr>
+
+ <td>nl</td>
+
+ <td>
+ (Combining Diacritical Marks)<br>
+ U+0301</td>
+
+ </tr>
+
+ <tr>
+
+ <td>ro</td>
+
+ <td>
+ (Latin Extended-A)<br>
+ U+0100 – U+017F<br>
+ (Latin Extended-B)<br>
+ U+0218 – U+0219<br>
+U+021A – U+021B
+ </td></tr>
+
+
+
+ <tr><td>el</td>
+
+ <td>
+ (Combining Diacritical Marks)<br>
+ U+0301<br>
+ U+0308<br>
+ (Greek and Coptic)<br>
+ U+0386 – U+0387<br>
+ U+0388 – U+03CE
+ </td>
+ </tr>
+
+
+ <tr>
+
+ <td>pt, es</td>
+
+ <td>(Currency symbols)<br>
+ U+20A1 – U+20A2<br>
+ U+20B3</td>
+ </tr>
+
+
+
+ <tr>
+ <td>ar</td>
+
+ <td>
+ (Arabic)<br>
+ U+060C – U+060D<br>
+ U+061B<br>
+ U+061E – U+061F<br>
+ U+0621 – U+063A<br>
+ U+0640 – U+0652<br>
+ U+0660 – U+066D<br>
+ U+0670<br>
+ </td>
+ </tr>
+
+ <tr>
+ <td>he</td>
+
+ <td>
+ (Hebrew)<br>
+ U+05B0 – U+05C3<br>
+ U+05D0 – U+05EA<br>
+ U+05F3 – U+05F4</td>
+ </tr>
+
+
+
+
+ <tr>
+
+ <td>bs, bg, mk, ru, sr</td>
+
+ <td>
+ (Latin Extended-A)<br>
+ U+0100 – U+017F<br>
+ (Cyrillic)<br>
+ U+0400 – U+045F</td>
+ </tr>
+
+ <tr>
+
+ <td>uk</td>
+
+ <td>
+ (Latin Extended-A)<br>
+ U+0100 – U+017F<br>
+ (Cyrillic)<br>
+ U+0400 – U+045F<br>
+ U+0490 – U+0491<br>
+ (Spacing Modifier Letters)<br>
+ U+02BC<br>
+(Letterlike Symbols)<br>
+ U+2116
+
+
+
+ </td>
+ </tr>
+
+
+
+
+ <tr>
+
+ <td>kk</td>
+
+ <td>
+ (Latin Extended-A)<br>
+ U+0100 – U+017F<br>
+ (Cyrillic)<br>
+ U+0400 – U+045F<br>
+ U+0492 – U+0493<br>
+ U+049A – U+049B<br>
+ U+04A2 – U+04A3<br>
+ U+04AE – U+04B1<br>
+ U+04BA – U+04BB<br>
+ U+04D8 – U+04D9<br>
+ U+04E8 – U+04E9<br>
+
+
+
+
+ </td>
+ </tr>
+
+ <tr>
+
+ <td>hu</td>
+
+ <td>
+ (Latin Extended-A)<br>
+ U+0100 – U+017F<br>
+ (General Punctuation)<br>
+ U+2052<br>
+ (Miscellaneous Mathematical Symbols-A)<br>
+U+27E8–U+27E9
+</td>
+ </tr>
+ </tbody>
+ </table>
+ </section>
+
+ <section id="schema" class="appendix">
+ <!--OddPage--><h2 id="h2_schema" role="heading" aria-level="1"><span class="secno">B. </span>Schema</h2>
+
+ <p><em>TBD</em></p>
+ </section>
+
+
+<section rel="bibo:Chapter" resource="#ref" typeof="bibo:Chapter" id="references" class="appendix"><!--OddPage--><h2 id="h2_references" role="heading" aria-level="1"><span class="secno">C. </span>References</h2><section rel="bibo:Chapter" resource="#ref" typeof="bibo:Chapter" id="normative-references"><h3 id="h3_normative-references" role="heading" aria-level="2"><span class="secno">C.1 </span>Normative references</h3><dl about="" class="bibliography"><dt id="bib-MHP">[MHP]</dt><dd rel="dcterms:requires">ETSI TS 101 812 V1.3.1, Digital Video Broadcasting (DVB); Multimedia Home
+</dd><dt id="bib-RFC2119">[RFC2119]</dt><dd rel="dcterms:requires">S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key words for use in RFCs to Indicate Requirement Levels.</cite></a> March 1997. Internet RFC 2119. URL: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a>
+</dd><dt id="bib-SDPUS">[SDPUS]</dt><dd rel="dcterms:requires">World Wide Web Consortium (W3C). <a href="http://www.w3.org/TR/ttml10-sdp-us/">TTML Simple Delivery Profile for Closed Captions (US)</a> (W3C Working Group Note, 05 February 2013)
+</dd><dt id="bib-SUBM">[SUBM]</dt><dd rel="dcterms:requires">World Wide Web Consortium (W3C). <a href="http://www.w3.org/Submission/2013/SUBM-ttml-ww-profiles-20130607/">TTML Text and Image Profiles for Internet Media Subtitles and Captions</a> (Member Submission, 07 June 2013)
+</dd><dt id="bib-TTML2">[TTML2]</dt><dd rel="dcterms:requires">World Wide Web Consortium (W3C). Timed Text Markup Language 2 (TTML 2)
+</dd><dt id="bib-UNICODE">[UNICODE]</dt><dd rel="dcterms:requires"><a href="http://www.unicode.org/versions/latest/"><cite>The Unicode Standard</cite></a>. URL: <a href="http://www.unicode.org/versions/latest/">http://www.unicode.org/versions/latest/</a>
+</dd><dt id="bib-xml-names">[xml-names]</dt><dd rel="dcterms:requires">Tim Bray; Dave Hollander; Andrew Layman; Richard Tobin; Henry Thompson et al. <a href="http://www.w3.org/TR/xml-names"><cite>Namespaces in XML 1.0 (Third Edition)</cite></a>. 8 December 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/xml-names">http://www.w3.org/TR/xml-names</a>
+</dd></dl></section><section rel="bibo:Chapter" resource="#ref" typeof="bibo:Chapter" id="informative-references"><h3 id="h3_informative-references" role="heading" aria-level="2"><span class="secno">C.2 </span>Informative references</h3><dl about="" class="bibliography"><dt id="bib-CEA-608">[CEA-608]</dt><dd rel="dcterms:references"><a href="http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/Line-21-Data-Service.aspx">Line-21 Data Services</a>, ANSI/CEA Standard.
+</dd><dt id="bib-CEA-708">[CEA-708]</dt><dd rel="dcterms:references"><a href="http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/CEA-708-D.aspx">Digital Television (DTV) Closed Captioning</a>, ANSI/CEA Standard.
+</dd><dt id="bib-CLDR">[CLDR]</dt><dd rel="dcterms:references">Unicode Consortium. <a href="http://cldr.unicode.org">The Common Locale Data Repository Project</a>
+</dd><dt id="bib-ST2052-1">[ST2052-1]</dt><dd rel="dcterms:references">SMPTE ST 2052-1, Timed Text Format (SMPTE-TT)
+</dd></dl></section></section></body></html>
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