--- a/ttml-ww-profiles/ttml-ww-profiles.html Sat Oct 31 12:02:25 2015 -0700
+++ b/ttml-ww-profiles/ttml-ww-profiles.html Sat Oct 31 22:26:01 2015 -0700
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- }
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-
-<body class="h-entry" role="document" id="respecDocument"><div class="head" role="contentinfo" id="respecHeader">
- <p>
-
-
- <a href="http://www.w3.org/"><img width="72" height="48" src="https://www.w3.org/Icons/w3c_home" alt="W3C"></a>
-
-
-
-
- </p>
- <h1 class="title p-name" id="title" property="dcterms:title">TTML Profiles for Internet Media Subtitles and Captions 1.0 (IMSC1)</h1>
-
- <h2 id="w3c-editor-s-draft-31-october-2015"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft <time property="dcterms:issued" class="dt-published" datetime="2015-10-31">31 October 2015</time></h2>
- <dl>
-
- <dt>This version:</dt>
- <dd><a class="u-url" href="https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml-ww-profiles/ttml-ww-profiles.html">https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml-ww-profiles/ttml-ww-profiles.html</a></dd>
- <dt>Latest published version:</dt>
- <dd><a href="http://www.w3.org/TR/ttml-imsc1/">http://www.w3.org/TR/ttml-imsc1/</a></dd>
-
-
- <dt>Latest editor's draft:</dt>
- <dd><a href="https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml-ww-profiles/ttml-ww-profiles.html">https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml-ww-profiles/ttml-ww-profiles.html</a></dd>
-
-
-
- <dt>Implementation report:</dt>
- <dd><a href="https://www.w3.org/wiki/TimedText/IMSC1_Implementation_Report">https://www.w3.org/wiki/TimedText/IMSC1_Implementation_Report</a></dd>
-
-
-
-
-
-
-
- <dt>Editor:</dt>
- <dd class="p-author h-card vcard" property="bibo:editor" resource="_:editor0"><span property="rdf:first" typeof="foaf:Person"><span property="foaf:name" class="p-name fn">Pierre Lemieux</span>, <span class="ed_mailto"><a class="u-email email" property="foaf:mbox" href="mailto:pal@sandflow.com">pal@sandflow.com</a></span></span>
-<span property="rdf:rest" resource="rdf:nil"></span>
-</dd>
-
-
-
- </dl>
-
-
-
-
-
- <p class="copyright">
- <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> ©
- 2015
-
- <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>).
-
- <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 rel="license" href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a>
-
-
- rules apply.
- </p>
-
-
- <hr>
-</div>
- <section id="abstract" class="introductory" property="dc:abstract"><h2 id="h-abstract" resource="#h-abstract"><span property="xhv:role" resource="xhv:heading">Abstract</span></h2>
- <p>This document specifies two profiles of [<cite><a class="bibref" href="#bib-TTML1">TTML1</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 class="bibref" href="#bib-ttml10-sdp-us">ttml10-sdp-us</a></cite>].</p>
-
- <p>The document defines extensions to [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>], as well as incorporates extensions specified in [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>] and
- [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>].</p>
-
- <p>Both profiles are based on [<cite><a class="bibref" href="#bib-SUBM">SUBM</a></cite>].</p>
- </section><section id="sotd" class="introductory"><h2 id="h-sotd" resource="#h-sotd"><span property="xhv:role" resource="xhv:heading">Status of This Document</span></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?subject=%5Bimsc%5D">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>)
- with <code>[imsc]</code> at the start of your email's subject.
-
-
-
-
-
-
- All comments are welcome.
-
-
- </p>
-
- <p>
- Please see the Working Group's <a href="https://www.w3.org/wiki/TimedText/IMSC1_Implementation_Report">implementation
- report</a>.
- </p>
-
-
-
- <p>
- For this specification to exit the CR stage, at least 2 independent implementations of every feature
- defined in this specification but not already present in [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] need to be documented in the implementation
- report. The implementation report is based on implementer-provided test results for the <a href="https://dvcs.w3.org/hg/ttml/file/tip/ttml-ww-profiles/testsuite">test suite</a> (tests and sample
- content) maintained by the Working Group. The Working Group does not require that implementations are publicly available
- but encourages them to be so.
- </p>
-
- <p>The Working Group expects the test suite and the implementation report to evolve significantly before the specification advances to Proposed Recommendation.</p>
- <p>The Working Group has not identified features "at risk" for this specification.</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" property="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>
-
- <p>This document is governed by the <a id="w3c_process_revision" href="http://www.w3.org/2015/Process-20150901/">1 September 2015 <abbr title="World Wide Web Consortium">W3C</abbr> Process Document</a>.
- </p>
-
-
-
-
-
-
-</section><section id="toc"><h2 class="introductory" id="h-toc" resource="#h-toc"><span property="xhv:role" resource="xhv:heading">Table of Contents</span></h2><ul class="toc" role="directory" id="respecContents"><li class="tocline"><a href="#scope" class="tocxref"><span class="secno">1. </span>Scope</a></li><li class="tocline"><a href="#conventions" class="tocxref"><span class="secno">2. </span>Documentation Conventions</a></li><li class="tocline"><a href="#terms" class="tocxref"><span class="secno">3. </span>Terms and Definitions</a></li><li class="tocline"><a href="#conformance" class="tocxref"><span class="secno">4. </span>Conformance</a></li><li class="tocline"><a href="#profiles" class="tocxref"><span class="secno">5. </span>Profiles</a><ul class="toc"><li class="tocline"><a href="#general" class="tocxref"><span class="secno">5.1 </span>General</a></li><li class="tocline"><a href="#text-profile" class="tocxref"><span class="secno">5.2 </span>Text Profile</a></li><li class="tocline"><a href="#image-profile" class="tocxref"><span class="secno">5.3 </span>Image Profile</a></li></ul></li><li class="tocline"><a href="#common-constraints" class="tocxref"><span class="secno">6. </span>Common Constraints</a><ul class="toc"><li class="tocline"><a href="#document-encoding" class="tocxref"><span class="secno">6.1 </span>Document Encoding</a></li><li class="tocline"><a href="#foreign-element-and-attributes" class="tocxref"><span class="secno">6.2 </span>Foreign Element and Attributes</a></li><li class="tocline"><a href="#namespaces" class="tocxref"><span class="secno">6.3 </span>Namespaces</a></li><li class="tocline"><a href="#overflow" class="tocxref"><span class="secno">6.4 </span>Overflow</a></li><li class="tocline"><a href="#related-video-object" class="tocxref"><span class="secno">6.5 </span>Related Video Object</a></li><li class="tocline"><a href="#synchronization" class="tocxref"><span class="secno">6.6 </span>Synchronization</a></li><li class="tocline"><a href="#extensions" class="tocxref"><span class="secno">6.7 </span>Extensions</a><ul class="toc"><li class="tocline"><a href="#ttp-aspectRatio" class="tocxref"><span class="secno">6.7.1 </span>ittp:aspectRatio</a></li><li class="tocline"><a href="#ttp-progressivelyDecodable" class="tocxref"><span class="secno">6.7.2 </span>ittp:progressivelyDecodable</a></li><li class="tocline"><a href="#tts-forcedDisplay" class="tocxref"><span class="secno">6.7.3 </span>itts:forcedDisplay</a></li><li class="tocline"><a href="#ttm-altText" class="tocxref"><span class="secno">6.7.4 </span>ittm:altText</a></li></ul></li><li class="tocline"><a href="#region" class="tocxref"><span class="secno">6.8 </span>Region</a><ul class="toc"><li class="tocline"><a href="#presented-region" class="tocxref"><span class="secno">6.8.1 </span>Presented Region</a></li><li class="tocline"><a href="#dimensions-and-position" class="tocxref"><span class="secno">6.8.2 </span>Dimensions and Position</a></li><li class="tocline"><a href="#maximum-number" class="tocxref"><span class="secno">6.8.3 </span>Maximum number</a></li></ul></li><li class="tocline"><a href="#hypothetical-render-model-1" class="tocxref"><span class="secno">6.9 </span>Hypothetical Render Model</a></li><li class="tocline"><a href="#common-features" class="tocxref"><span class="secno">6.10 </span>Features</a></li></ul></li><li class="tocline"><a href="#text-profile-constraints" class="tocxref"><span class="secno">7. </span>Text Profile Constraints</a><ul class="toc"><li class="tocline"><a href="#text-profile-designator" class="tocxref"><span class="secno">7.1 </span>Profile Designator</a></li><li class="tocline"><a href="#recommended-character-sets" class="tocxref"><span class="secno">7.2 </span>Recommended Character Sets</a></li><li class="tocline"><a href="#reference-fonts-1" class="tocxref"><span class="secno">7.3 </span>Reference Fonts</a></li><li class="tocline"><a href="#features" class="tocxref"><span class="secno">7.4 </span>Features</a></li></ul></li><li class="tocline"><a href="#image-profile-constraints" class="tocxref"><span class="secno">8. </span>Image Profile Constraints</a><ul class="toc"><li class="tocline"><a href="#image-profile-designator" class="tocxref"><span class="secno">8.1 </span>Profile Designator</a></li><li class="tocline"><a href="#presented-image" class="tocxref"><span class="secno">8.2 </span>Presented Image</a><ul class="toc"><li class="tocline"><a href="#definition" class="tocxref"><span class="secno">8.2.1 </span>Definition</a></li><li class="tocline"><a href="#number-per-region" class="tocxref"><span class="secno">8.2.2 </span>Number per Region</a></li></ul></li><li class="tocline"><a href="#div-element" class="tocxref"><span class="secno">8.3 </span><code>div</code> element</a></li><li class="tocline"><a href="#features-1" class="tocxref"><span class="secno">8.4 </span>Features</a></li></ul></li><li class="tocline"><a href="#hypothetical-render-model" class="tocxref"><span class="secno">9. </span>Hypothetical Render Model</a><ul class="toc"><li class="tocline"><a href="#overview-non-normative" class="tocxref"><span class="secno">9.1 </span>Overview (non-normative)</a></li><li class="tocline"><a href="#hypothetical-render-model-general" class="tocxref"><span class="secno">9.2 </span>General</a></li><li class="tocline"><a href="#paint-regions" class="tocxref"><span class="secno">9.3 </span>Paint Regions</a></li><li class="tocline"><a href="#paint-images" class="tocxref"><span class="secno">9.4 </span>Paint Images</a></li><li class="tocline"><a href="#paint-text" class="tocxref"><span class="secno">9.5 </span>Paint Text</a></li></ul></li><li class="tocline"><a href="#reference-fonts" class="tocxref"><span class="secno">A. </span>Reference Fonts</a></li><li class="tocline"><a href="#recommended-unicode-code-points-per-language" class="tocxref"><span class="secno">B. </span>Recommended Character Sets</a></li><li class="tocline"><a href="#forced-content" class="tocxref"><span class="secno">C. </span>Forced content (non-normative)</a></li><li class="tocline"><a href="#wcag-applications" class="tocxref"><span class="secno">D. </span>WCAG Considerations</a></li><li class="tocline"><a href="#sample-instance" class="tocxref"><span class="secno">E. </span>Sample Document Instance (non-normative)</a></li><li class="tocline"><a href="#features-and-extensions" class="tocxref"><span class="secno">F. </span>Extensions</a><ul class="toc"><li class="tocline"><a href="#general-1" class="tocxref"><span class="secno">F.1 </span>General</a></li><li class="tocline"><a href="#progressivelydecodable" class="tocxref"><span class="secno">F.2 </span>#progressivelyDecodable</a></li><li class="tocline"><a href="#aspectratio" class="tocxref"><span class="secno">F.3 </span>#aspectRatio</a></li><li class="tocline"><a href="#forceddisplay" class="tocxref"><span class="secno">F.4 </span>#forcedDisplay</a></li><li class="tocline"><a href="#alttext" class="tocxref"><span class="secno">F.5 </span>#altText</a></li><li class="tocline"><a href="#linepadding" class="tocxref"><span class="secno">F.6 </span>#linePadding</a></li><li class="tocline"><a href="#multirowalign" class="tocxref"><span class="secno">F.7 </span>#multiRowAlign</a></li></ul></li><li class="tocline"><a href="#xml-schemas" class="tocxref"><span class="secno">G. </span>XML Schema Definitions (non-normative)</a></li><li class="tocline"><a href="#simple-scripts" class="tocxref"><span class="secno">H. </span>Simple Scripts</a></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">I. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">I.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">I.2 </span>Informative references</a></li></ul></li></ul></section>
-
-
-
- <section id="scope" typeof="bibo:Chapter" resource="#scope" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-scope" resource="#h-scope"><span property="xhv:role" resource="xhv:heading"><span class="secno">1. </span>Scope</span></h2>
-
- <p>This document specifies two profiles of [<cite><a class="bibref" href="#bib-TTML1">TTML1</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 text-only profile is a strict superset of [<cite><a class="bibref" href="#bib-ttml10-sdp-us">ttml10-sdp-us</a></cite>].</p>
-
- <p>The document defines extensions to [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>], as well as incorporates extensions specified in [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>] and
- [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>].</p>
- </section>
-
- <section id="conventions" typeof="bibo:Chapter" resource="#conventions" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-conventions" resource="#h-conventions"><span property="xhv:role" resource="xhv:heading"><span class="secno">2. </span>Documentation Conventions</span></h2>
-
- <p>This specification uses the same conventions as [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] for the specification of parameter attributes, styling attributes and metadata elements. In particular, Section 2.3 of [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] specifies conventions used in the XML representation of elements.</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>
- </section>
-
- <section id="terms" typeof="bibo:Chapter" resource="#terms" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-terms" resource="#h-terms"><span property="xhv:role" resource="xhv:heading"><span class="secno">3. </span>Terms and Definitions</span></h2>
-
- <p><dfn data-dfn-type="dfn" id="dfn-default-region">Default Region</dfn>. See Section 9.3.1 at [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>].</p>
-
- <p><dfn data-dfn-type="dfn" id="dfn-document-instance">Document Instance</dfn>. See Section 2.2 at [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>].</p>
-
- <p><dfn data-dfn-type="dfn" id="dfn-intermediate-synchronic-document">Intermediate synchronic document</dfn>. See Section 9.3.2 at [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>].</p>
-
- <p><dfn data-dfn-type="dfn" id="dfn-processor">Processor</dfn>. Either a <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">Presentation processor</a> or a <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">Transformation processor</a>.</p>
-
- <p><dfn data-dfn-type="dfn" id="dfn-presentation-processor">Presentation processor</dfn>. See Section 2.2 at [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>].</p>
-
- <p><dfn data-dfn-type="dfn" id="dfn-transformation-processor">Transformation processor</dfn>. See Section 2.2 at [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>].</p>
-
- <p><dfn data-dfn-type="dfn" id="dfn-related-media-object">Related Media Object</dfn>. See Section 2.2 at [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>].</p>
-
- <p><dfn data-dfn-type="dfn" id="dfn-related-video-object">Related Video Object</dfn>. A <a href="#dfn-related-media-object" class="internalDFN" data-link-type="dfn">Related Media Object</a> that consists of a sequence of image frames, each a rectangular array of pixels.</p>
-
- <p><dfn data-dfn-type="dfn" id="dfn-text-alternative">text alternative</dfn>. As defined in [<cite><a class="bibref" href="#bib-WCAG20">WCAG20</a></cite>].</p>
-
- </section>
-
- <section id="conformance" typeof="bibo:Chapter" resource="#conformance" property="bibo:hasPart"><!--OddPage--><h2 id="h-conformance" resource="#h-conformance"><span property="xhv:role" resource="xhv:heading"><span class="secno">4. </span>Conformance</span></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 id="respecRFC2119">The key words <em class="rfc2119" title="MAY">MAY</em>, <em class="rfc2119" title="SHALL">SHALL</em>, <em class="rfc2119" title="SHALL NOT">SHALL NOT</em>, <em class="rfc2119" title="SHOULD">SHOULD</em>, and <em class="rfc2119" title="SHOULD NOT">SHOULD NOT</em> are
- to be interpreted as described in [<cite><a class="bibref" href="#bib-RFC2119">RFC2119</a></cite>].
-</p>
-
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> that conforms to a profile defined herein:</p>
-
-
-
- <ul>
- <li><em class="rfc2119" title="SHALL">SHALL</em> satisfy all normative provisions specified by the profile;</li>
- <li><em class="rfc2119" title="MAY">MAY</em> use any vocabulary, syntax or attribute values whose interpretation will be successfully processed by a processor that supports "permitted" features;</li>
- <li><em class="rfc2119" title="SHALL NOT">SHALL NOT</em> use any vocabulary, syntax or attribute values that would require the processor to implement any "prohibited" features to successfully process the document.</li>
- </ul>
-
-
-
- <p>A <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> that conforms to a profile defined in this specification:</p>
-
- <ul>
- <li><em class="rfc2119" title="SHALL">SHALL</em> satisfy the Generic Processor Conformance requirements at Section 3.2.1 of [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>];</li>
-
- <li><em class="rfc2119" title="SHALL">SHALL</em> satisfy all normative provisions specified by the profile; and</li>
-
- <li><em class="rfc2119" title="SHALL">SHALL</em> implement presentation semantic support for all features designated as "permitted" by the profile, subject to
- any additional constraints on features as specified by the profile.</li>
- </ul>
-
- <p>A <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a> that conforms to a profile defined in this specification:</p>
-
- <ul>
- <li><em class="rfc2119" title="SHALL">SHALL</em> satisfy the Generic Processor Conformance requirements at Section 3.2.1 of [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>];</li>
-
- <li><em class="rfc2119" title="SHALL">SHALL</em> satisfy all normative provisions specified by the profile; and</li>
-
- <li><em class="rfc2119" title="SHALL">SHALL</em> implement transformation semantic support for all features designated as "permitted" by the profile, subject to
- any additional constraints on features as specified by the profile.</li>
- </ul>
-
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h-note1"><span>Note</span></div><p class="">The use of the term <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> (<a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a>) within this specification
- does not imply conformance to the DFXP Presentation Profile (DFXP Transformation Profile) specified in [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>]. In other
- words, it is not considered an error for a <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> (<a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a>) to conform to a
- profile defined in this specification without also conforming to the DFXP Presentation Profile (DFXP Transformation
- Profile).</p></div>
-
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h-note2"><span>Note</span></div><p class="">This specification does not specify <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> or <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a> behavior when processing or transforming a non-conformant <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>.</p></div>
- </section>
-
- <section id="profiles" typeof="bibo:Chapter" resource="#profiles" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-profiles" resource="#h-profiles"><span property="xhv:role" resource="xhv:heading"><span class="secno">5. </span>Profiles</span></h2>
-
- <section id="general" typeof="bibo:Chapter" resource="#general" property="bibo:hasPart">
- <h3 id="h-general" resource="#h-general"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.1 </span>General</span></h3>
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> conform to the <a href="#dfn-text-profile" class="internalDFN" data-link-type="dfn">Text Profile</a> and <a href="#dfn-image-profile" class="internalDFN" data-link-type="dfn">Image Profile</a> simultaneously.</p>
-
- <p>In applications that require subtitle/caption content in image form to be simultaneously available in text form, two
- distinct <a data-lt="Document Instance" href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instances</a>, one conforming to the <a href="#dfn-text-profile" class="internalDFN" data-link-type="dfn">Text Profile</a> and the other conforming to the <a href="#dfn-image-profile" class="internalDFN" data-link-type="dfn">Image Profile</a>,
- <em class="rfc2119" title="SHOULD">SHOULD</em> be offered. In addition, the <a href="#dfn-text-profile" class="internalDFN" data-link-type="dfn">Text Profile</a> <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHOULD">SHOULD</em> be associated with the <a href="#dfn-image-profile" class="internalDFN" data-link-type="dfn">Image Profile</a>
- <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> such that, when image content is encountered, assistive technologies have access to its corresponding text
- form. The method by which this association is made is left to each application.</p>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note3"><span>Note</span></div><p class="">The <code>ittm:altText</code> element specified <a href="#ttm-altText" class="sec-ref"><span class="secno">6.7.4</span> <span class="sec-title">ittm:altText</span></a> also allows text equivalent
- string to be associated with an image, e.g. to support indexation of the content and also facilitate quality checking of the
- document during authoring.</p></div>
-
- <p>Annex <a href="#wcag-applications" class="sec-ref"><span class="secno">D.</span> <span class="sec-title">WCAG Considerations</span></a> specifically discusses this specification in the context of the [<cite><a class="bibref" href="#bib-WCAG20">WCAG20</a></cite>]
- guidelines.</p>
- </section>
-
- <section id="text-profile" typeof="bibo:Chapter" resource="#text-profile" property="bibo:hasPart">
- <h3 id="h-text-profile" resource="#h-text-profile"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.2 </span>Text Profile</span></h3>
-
- <p>The <dfn data-dfn-type="dfn" id="dfn-text-profile">Text Profile</dfn> consists of Sections <a href="#common-constraints" class="sec-ref"><span class="secno">6.</span> <span class="sec-title">Common Constraints</span></a> and <a href="#text-profile-constraints" class="sec-ref"><span class="secno">7.</span> <span class="sec-title">Text Profile Constraints</span></a>.</p>
- </section>
-
- <section id="image-profile" typeof="bibo:Chapter" resource="#image-profile" property="bibo:hasPart">
- <h3 id="h-image-profile" resource="#h-image-profile"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3 </span>Image Profile</span></h3>
-
- <p>The <dfn data-dfn-type="dfn" id="dfn-image-profile">Image Profile</dfn> consists of Sections <a href="#common-constraints" class="sec-ref"><span class="secno">6.</span> <span class="sec-title">Common Constraints</span></a> and <a href="#image-profile-constraints" class="sec-ref"><span class="secno">8.</span> <span class="sec-title">Image Profile Constraints</span></a>.</p>
- </section>
- </section>
-
- <section id="common-constraints" typeof="bibo:Chapter" resource="#common-constraints" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-common-constraints" resource="#h-common-constraints"><span property="xhv:role" resource="xhv:heading"><span class="secno">6. </span>Common Constraints</span></h2>
-
- <section id="document-encoding" typeof="bibo:Chapter" resource="#document-encoding" property="bibo:hasPart">
- <h3 id="h-document-encoding" resource="#h-document-encoding"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.1 </span>Document Encoding</span></h3>
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHALL">SHALL</em> use UTF-8 character encoding as specified in [<cite><a class="bibref" href="#bib-UNICODE">UNICODE</a></cite>].</p>
- </section>
-
- <section id="foreign-element-and-attributes" typeof="bibo:Chapter" resource="#foreign-element-and-attributes" property="bibo:hasPart">
- <h3 id="h-foreign-element-and-attributes" resource="#h-foreign-element-and-attributes"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.2 </span>Foreign Element and Attributes</span></h3>
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="MAY">MAY</em> contain elements and attributes that are neither specifically permitted nor forbidden by a
- profile.</p>
- </section>
-
- <section id="namespaces" typeof="bibo:Chapter" resource="#namespaces" property="bibo:hasPart">
- <h3 id="h-namespaces" resource="#h-namespaces"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3 </span>Namespaces</span></h3>
-
- <p>The following namespaces (see [<cite><a class="bibref" href="#bib-xml-names">xml-names</a></cite>]) are used in this specification:</p>
-
- <table class="simple">
- <thead>
- <tr>
- <th>Name</th>
-
- <th>Prefix</th>
-
- <th>Value</th>
-
- <th>Defining Specification</th>
- </tr>
- </thead>
-
- <tbody>
- <tr>
- <td>XML</td>
-
- <td>xml</td>
-
- <td>http://www.w3.org/XML/1998/namespace</td>
-
- <td>[<cite><a class="bibref" href="#bib-xml-names">xml-names</a></cite>]</td>
- </tr>
-
- <tr>
- <td>TT Parameter</td>
-
- <td>ttp</td>
-
- <td>http://www.w3.org/ns/ttml#parameter</td>
-
- <td>[<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>]</td>
- </tr>
-
- <tr>
- <td>TT Styling</td>
-
- <td>tts</td>
-
- <td>http://www.w3.org/ns/ttml#styling</td>
-
- <td>[<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>]</td>
- </tr>
-
- <tr>
- <td>TT Feature</td>
-
- <td><em>none</em></td>
-
- <td>http://www.w3.org/ns/ttml/feature/</td>
-
- <td>[<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>]</td>
- </tr>
-
- <tr>
- <td>SMPTE-TT Extension</td>
-
- <td>smpte</td>
-
- <td>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt</td>
-
- <td>[<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>]</td>
- </tr>
-
- <tr>
- <td>EBU-TT Styling</td>
-
- <td>ebutts</td>
-
- <td>urn:ebu:tt:style</td>
-
- <td>[<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>]</td>
- </tr>
-
- <tr>
- <td>EBU-TT Metadata</td>
-
- <td>ebuttm</td>
-
- <td>urn:ebu:tt:metadata</td>
-
- <td>[<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>]</td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Styling</td>
-
- <td>itts</td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1#styling</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Parameter</td>
-
- <td>ittp</td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1#parameter</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Metadata</td>
-
- <td>ittm</td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1#metadata</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Extension</td>
-
- <td><em>none</em></td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1/extension/</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Text Profile Designator</td>
-
- <td><em>none</em></td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1/text</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Image Profile Designator</td>
-
- <td><em>none</em></td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1/image</td>
-
- <td><em>This specification</em></td>
- </tr>
- </tbody>
- </table>
-
- <p>The namespace prefix values defined above are for convenience and <a data-lt="Document Instance" href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instances</a> <em class="rfc2119" title="MAY">MAY</em> use any prefix value that
- conforms to [<cite><a class="bibref" href="#bib-xml-names">xml-names</a></cite>].</p>
-
- <p>The namespaces defined by this specification are mutable [<cite><a class="bibref" href="#bib-namespaceState">namespaceState</a></cite>]; all undefined names in these namespaces are reserved for future standardization by the <abbr title="World Wide Web Consortium">W3C</abbr>.</p>
- </section>
-
- <section id="overflow" typeof="bibo:Chapter" resource="#overflow" property="bibo:hasPart">
- <h3 id="h-overflow" resource="#h-overflow"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.4 </span>Overflow</span></h3>
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHOULD">SHOULD</em> be authored assuming strict clipping of content that falls out of region areas, regardless of
- the computed value of <code>tts:overflow</code> for the region.</p>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note4"><span>Note</span></div><p class="">As specified in [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>], <code>tts:overflow</code> has no effect on the extent of the region, and hence
- the total normalized drawing area S(En) at <a href="#paint-regions" class="sec-ref"><span class="secno">9.3</span> <span class="sec-title">Paint Regions</span></a>.</p></div>
- </section>
-
- <section id="related-video-object" typeof="bibo:Chapter" resource="#related-video-object" property="bibo:hasPart">
- <h3 id="h-related-video-object" resource="#h-related-video-object"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.5 </span>Related Video Object</span></h3>
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="MAY">MAY</em> be associated with a <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a>.</p>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note5"><span>Note</span></div><p class="">While this specification contains specific provisions when a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> is associated with a <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a>, it does not prevent the use of a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> with other kinds of <a href="#dfn-related-media-object" class="internalDFN" data-link-type="dfn">Related Media Object</a>, e.g. an audio object.</p></div>
- </section>
-
- <section id="synchronization" typeof="bibo:Chapter" resource="#synchronization" property="bibo:hasPart">
- <h3 id="h-synchronization" resource="#h-synchronization"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.6 </span>Synchronization</span></h3>
-
- <p>Each <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> of the <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> is intended to be displayed on a specific frame and
- removed on a specific frame of the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a>.</p>
-
- <p>When mapping a media time expression M to a frame F of a <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a>, e.g. for the purpose of rendering a
- <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> onto the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a>, the <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> <em class="rfc2119" title="SHALL">SHALL</em> map M to the frame F with the
- presentation time that is the closest to, but not less, than M.</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>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note6"><span>Note</span></div><p class="">In typical scenario, the same video program (the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a>) will be used for <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>
- authoring, delivery and user playback. The mapping from media time expression to <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> above allows the author
- to precisely associate subtitle video content with video frames, e.g. around scene transitions. In circumstances where the
- video program is downsampled during delivery, the application can specify that, at playback, the relative video object be
- considered the delivered video program upsampled to is original rate, thereby allowing subtitle content to be rendered at the
- same temporal locations it was authored.</p></div>
-
- </section>
-
- <section id="extensions" typeof="bibo:Chapter" resource="#extensions" property="bibo:hasPart">
- <h3 id="h-extensions" resource="#h-extensions"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.7 </span>Extensions</span></h3>
-
- <section id="ttp-aspectRatio" typeof="bibo:Chapter" resource="#ttp-aspectRatio" property="bibo:hasPart">
- <h4 id="h-ttp-aspectratio" resource="#h-ttp-aspectratio"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.7.1 </span>ittp:aspectRatio</span></h4>
-
- <p>The <code>ittp:aspectRatio</code> attributes allows authorial control of the mapping of the root container of a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> to the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> frame.</p>
-
- <p>If present, the <code>ittp:aspectRatio</code> attribute <em class="rfc2119" title="SHALL">SHALL</em> conform to the following syntax:</p>
-
- <table class="syntax">
- <tbody>
- <tr>
- <td>
- <div class="exampleInner">
- <pre>ittp:aspectRatio
- : numerator denominator // with int(numerator) != 0 and int(denominator) != 0
- // where int(s) parses string s as a decimal integer.
-
-numerator | denominator
- : <digit>+
-</pre>
- </div>
- </td>
- </tr>
- </tbody>
- </table>
-
- <p>The root container of a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHALL">SHALL</em> be mapped to the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> frame according to the
- following:</p>
-
- <ol>
- <li>
- <p>If <code>ittp:aspectRatio</code> is present, the root container <em class="rfc2119" title="SHALL">SHALL</em> be mapped to a rectangular area within the
- <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> such that:</p>
-
- <ol style="list-style-type: lower-roman;">
- <li>the ratio of the width to the height of the rectangular area is equal to <code>ittp:aspectRatio</code>,</li>
-
- <li>the center of the rectangular area is collocated with the center of the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> frame,</li>
-
- <li>the rectangular area (including its boundary) is entirely within the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> frame (including its
- boundary), and</li>
-
- <li>the rectangular area has a height or width equal to that of the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> frame.</li>
- </ol>
- </li>
-
- <li>
- <p>Otherwise, the root container of a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHALL">SHALL</em> be mapped to the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> frame in its
- entirety.</p>
- </li>
- </ol>
-
- <p>An <code>ittp:aspectRatio</code> attribute is considered to be significant only when specified on the <code>tt</code>
- element.</p>
-
-<aside class="example"><div class="example-title"><span>Example 2</span></div>
-<p>Region <code>"A"</code> in the following document would be positioned 20% from the left edge of a <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> with an aspect ratio of 16:9,
- or 10% from the left edge of a <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> with an aspect ratio of 4:3.</p>
-<pre><tt
- xmlns="http://www.w3.org/ns/ttml"
- xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
- xmlns:tts="http://www.w3.org/ns/ttml#styling"
- xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
- xmlns:ittp="http://www.w3.org/ns/ttml/profile/imsc1#parameter"
- ittp:aspectRatio="4 3"
- tts:extent="400px 300px"
- >
- ...
- <region id="A" tts:origin="40px 10px" tts:extent="320px 10px">
- ...
-</tt>
-</pre>
-<p>In other words, <code>tts:extent</code>, when present on the <code>tt</code> element, determines the size of <code>"px"</code> units relative to the root container. <code>ttp:aspectRatio</code> is independently used to map the root container to the <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a>.
-</p></aside>
-
-<div class="note"><div class="note-title" aria-level="5" role="heading" id="h-note7"><span>Note</span></div><p class="">
-The <code>ittp:aspectRatio</code> parameter effectively defines the intended display aspect ratio (DAR) of the root container, while
- the <code>tts:extent</code> style property on the root element effectively defines the intended storage aspect ratio (SAR) of the root container.
-</p></div>
- </section>
- <section id="ttp-progressivelyDecodable" typeof="bibo:Chapter" resource="#ttp-progressivelyDecodable" property="bibo:hasPart">
- <h4 id="h-ttp-progressivelydecodable" resource="#h-ttp-progressivelydecodable"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.7.2 </span>ittp:progressivelyDecodable</span></h4>
-
- <p>A <a href="#dfn-progressively-decodable-document-instance" class="internalDFN" data-link-type="dfn">progressively decodable Document Instance</a> is structured to facilitate presentation before the document is
- received in its entirety, and can be identified using <code>ittp:progressivelyDecodable</code> attribute.</p>
-
- <p>A <dfn data-dfn-type="dfn" id="dfn-progressively-decodable-document-instance">progressively decodable Document Instance</dfn> is a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> that conforms to the following:</p>
-
- <ol>
- <li>no attribute or element of the TTML timing vocabulary is present within the <code>head</code> element;</li>
-
- <li>given two <a data-lt="intermediate synchronic document" href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic documents</a> <em>A</em> and <em>B</em>
- of the <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>, with start times <em>TA</em> and <em>TB</em>, respectively, <em>TA</em> is not greater than
- <em>TB</em> if <em>A</em> includes a <code>p</code> element that lexically precedes any <code>p</code>
- element that <em>B</em> includes;
- </li>
-
- <li>no attribute of the TTML timing vocabulary is present on a descendant element of <code>p</code>; and</li>
-
- <li>no element <em>E1</em> explicitly references another element <em>E2</em> where the opening tag of <em>E2</em> is lexically subsequent to the opening tag of <em>E1</em>.</li>
- </ol>
-
- <p>If present, the <code>ittp:progressivelyDecodable</code> attribute <em class="rfc2119" title="SHALL">SHALL</em> conform to the following syntax:</p>
-
- <table class="syntax">
- <tbody>
- <tr>
- <td>
- <div class="exampleInner">
- <pre>ittp:progressivelyDecodable
- : "true"
- | "false"
-</pre>
- </div>
- </td>
- </tr>
- </tbody>
- </table>
-
- <p>An <code>ittp:progressivelyDecodable</code> attribute is considered to be significant only when specified on the
- <code>tt</code> element.</p>
-
- <p>If not specified, the value of <code>ittp:progressivelyDecodable</code> <em class="rfc2119" title="SHALL">SHALL</em> be considered to be equal to "false".</p>
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> for which the computed value of <code>ittp:progressivelyDecodable</code> is "true" <em class="rfc2119" title="SHALL">SHALL</em> be a
- <a href="#dfn-progressively-decodable-document-instance" class="internalDFN" data-link-type="dfn">progressively decodable Document Instance</a>.</p>
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> for which the computed value of <code>ittp:progressivelyDecodable</code> is "false" is neither
- asserted to be a <a href="#dfn-progressively-decodable-document-instance" class="internalDFN" data-link-type="dfn">progressively decodable Document Instance</a> nor asserted not to be a progressively decodable <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>.</p>
-
- <div class="example"><div class="example-title"><span>Example 3</span></div><pre class="example"><tt
- xmlns="http://www.w3.org/ns/ttml"
- xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
- xmlns:tts="http://www.w3.org/ns/ttml#styling"
- xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
- xmlns:ittp="http://www.w3.org/ns/ttml/profile/imsc1#parameter"
- ittp:progressivelyDecodable="true"
- >
- ...
-</tt></pre></div>
-
- <div class="note"><div class="note-title" aria-level="5" role="heading" id="h-note8"><span>Note</span></div><div class="">
- <p>[<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] specifies explicitly referencing of elements identified using <code>xml:id</code> in the following
- circumstances:</p>
-
- <ul>
- <li>an element in <code>body</code> referencing <code>region</code> elements. In this case, Requirement 4 above is
- always satisfied.</li>
-
- <li>an element in <code>body</code> referencing <code>style</code> elements. In this case, Requirement 4 above is
- always satisfied.</li>
-
- <li>a <code>region</code> element referencing <code>style</code> elements. In this case, Requirement 4 above is always
- satisfied.</li>
-
- <li>a <code>style</code> element referencing other <code>style</code> elements. In this case, Requirement 4 provides an
- optimization of <code>style</code> element ordering within the <code>head</code> element.</li>
-
- <li>a <code>ttm:actor</code> element referencing a <code>ttm:agent</code> element. In this case, Requirement 4 provides
- optimization of metadata elements ordering within the document.</li>
-
- <li>a content element referencing <code>ttm:agent</code> elements using the <code>ttm:agent</code> attribute. In this
- case, Requirement 4 provides optimization of metadata elements ordering within the document.</li>
- </ul>
- </div></div>
- </section>
-
- <section id="tts-forcedDisplay" typeof="bibo:Chapter" resource="#tts-forcedDisplay" property="bibo:hasPart">
- <h4 id="h-tts-forceddisplay" resource="#h-tts-forceddisplay"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.7.3 </span>itts:forcedDisplay</span></h4>
-
- <p><code>itts:forcedDisplay</code> can be used to hide content whose computed value of <code>tts:visibility</code> is <code>"visible"</code> when the processor has been configured to do so via the application parameter <code>displayForcedOnlyMode</code>.</p>
-
- <p>If and only if the value of <code>displayForcedOnlyMode</code> is "true", a content element with a <code>itts:forcedDisplay</code>
- computed value of "false" <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> produce any visible rendering, but still affect layout, regardless of the computed
- value of <code>tts:visibility</code>.</p>
-
- <p>The <code>itts:forcedDisplay</code> attribute shall conform to the following:</p>
-
- <table class="simple">
- <colgroup>
- <col style="width:25%" span="1">
- <col span="1">
- </colgroup>
-
- <tbody>
- <tr>
- <td><em>Values:</em></td>
-
- <td><code>false | true</code></td>
- </tr>
-
- <tr>
- <td><em>Initial:</em></td>
-
- <td><code>false</code></td>
- </tr>
-
- <tr>
- <td><em>Applies to:</em></td>
-
- <td><code>body</code>, <code>div</code>, <code>p</code>, <code>region</code>, <code>span</code></td>
- </tr>
-
- <tr>
- <td><em>Inherited:</em></td>
-
- <td>yes</td>
- </tr>
-
- <tr>
- <td><em>Percentages:</em></td>
-
- <td>N/A</td>
- </tr>
-
- <tr>
- <td><em>Animatable:</em></td>
-
- <td>discrete</td>
- </tr>
- </tbody>
- </table>
-
- <p>Annex <a href="#forced-content" class="sec-ref"><span class="secno">C.</span> <span class="sec-title">Forced content (non-normative)</span></a> illustrates the use of <code>itts:forcedDisplay</code> in an application in which a
- single document contains both hard of hearing captions and translated foreign language subtitles, using
- <code>itts:forcedDisplay</code> to display translation subtitles always, independently of whether the hard of hearing
- captions are displayed or hidden.</p>
-
- <p>The <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> <em class="rfc2119" title="SHALL">SHALL</em> accept an optional boolean parameter called <code>displayForcedOnlyMode</code>,
- whose value <em class="rfc2119" title="MAY">MAY</em> be set by a context external to the <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a>. If not set, the value of
- <code>displayForcedOnlyMode</code> <em class="rfc2119" title="SHALL">SHALL</em> be assumed to be equal to "false".</p>
-
- <p>The algorithm for setting the <code>displayForcedOnlyMode</code> parameter based on the circumstances under which the
- <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> is presented is left to the application.</p>
-
- <div class="example"><div class="example-title"><span>Example 4</span></div><pre class="example">...
-<head>
- ...
- <region xml:id="r1" tts:origin="10% 2%" tts:extent="80% 10%" tts:color="white" itts:forcedDisplay="true" tts:backgroundColor="black"/>
- <region xml:id="r2" tts:origin="10% 80%" tts:extent="80% 88%" tts:color="white" tts:backgroundColor="black"/>
- ...
-</head>
-...
-<div>
- <p region="r1" begin="1s" end="6s">Lycée</p>
-
- <!-- the following will not appear if displayForcedOnlyMode='true' -->
- <p region="r2" begin="4s" end="6s">Nous étions inscrits au même lycée.</p>
-</div>
-...</pre></div>
-
-
- <div class="note"><div class="note-title" aria-level="5" role="heading" id="h-note9"><span>Note</span></div><p class="">As specified in [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>], the background of a region can be visible even if the computed value of <code>tts:visibility</code> equals
- "hidden" for all active content within. The background of a region for which <code>itts:forcedDisplay</code> equals "true" can therefore remain visible even if <code>itts:forcedDisplay</code> equals "false" for all active
- content elements within the region and <code>displayForcedOnlyMode</code> equals "true". Authors can avoid this situation, for instance, by ensuring that content
- elements and the regions that they are flowed into always have the same value of <code>itts:forcedDisplay</code>.</p></div>
-
- <div class="note"><div class="note-title" aria-level="5" role="heading" id="h-note10"><span>Note</span></div><p class="">Although <code>itts:forcedDisplay</code>, like all the TTML style attributes, has no defined semantics on a
- <code>br</code> content element, <code>itts:forcedDisplay</code> will apply to a <code>br</code> content element if it is
- either defined on an ancestor content element of the <code>br</code> content element or it is applied to a region element
- corresponding to a region that the <code>br</code> content element is being flowed into.</p></div>
-
- <div class="note"><div class="note-title" aria-level="5" role="heading" id="h-note11"><span>Note</span></div><p class="">It is expected that the functionality of <code>itts:forcedDisplay</code> will be mapped to a conditional
- style construct in a future revision of this specification.</p></div>
- </section>
-
- <section id="ttm-altText" typeof="bibo:Chapter" resource="#ttm-altText" property="bibo:hasPart">
- <h4 id="h-ttm-alttext" resource="#h-ttm-alttext"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.7.4 </span>ittm:altText</span></h4>
-
- <p><code>ittm:altText</code> allows an author to provide a text string equivalent for an element, typically an image. This
- text equivalent <em class="rfc2119" title="MAY">MAY</em> be used to support indexing of the content and also facilitate quality checking of the document during
- authoring.</p>
-
- <p>The <code>ittm:altText</code> element <em class="rfc2119" title="SHALL">SHALL</em> conform to the following syntax:</p>
-
- <table class="syntax">
- <tbody>
- <tr>
- <td>
- <div class="exampleInner">
- <pre><ittm:altText
- xml:id = ID
- xml:lang = string
- xml:space = (default|preserve)
- {any attribute not in the default namespace, any TT namespace or any IMSC 1.0 namespace}>
- Content: #PCDATA
-</ittm:altText>
-</pre>
- </div>
- </td>
- </tr>
- </tbody>
- </table>
-
- <p>The <code>ittm:altText</code> element <em class="rfc2119" title="SHALL">SHALL</em> be a child of the <code>metadata</code> element.</p>
-
- <p><a href="#image-profile-constraints" class="sec-ref"><span class="secno">8.</span> <span class="sec-title">Image Profile Constraints</span></a> specifies the use of the <code>ittm:altText</code> element with images.</p>
-
-<div class="example"><div class="example-title"><span>Example 5</span></div><pre class="example">...
-<div region="r1" begin="1s" end="6s" smpte:backgroundImage="1.png">
- <metadata>
- <ittm:altText>Nous étions inscrits au même lycée.</ttm:title>
- </metadata>
-</div>
-...</pre></div>
-
- <div class="note"><div class="note-title" aria-level="5" role="heading" id="h-note12"><span>Note</span></div><p class="">In contrast to the common use of <code>alt</code> attributes in [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>], the <code>ittm:altText</code>
- attribute content is not intended to be displayed in place of the element if the element is not loaded. The
- <code>ittm:altText</code> attribute content can however be read and used by assistive technologies.</p></div>
- </section>
-
-
-
- </section>
-
- <section id="region" typeof="bibo:Chapter" resource="#region" property="bibo:hasPart">
- <h3 id="h-region" resource="#h-region"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.8 </span>Region</span></h3>
-
- <section id="presented-region" typeof="bibo:Chapter" resource="#presented-region" property="bibo:hasPart">
- <h4 id="h-presented-region" resource="#h-presented-region"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.8.1 </span>Presented Region</span></h4>
-
- <p>A <dfn data-dfn-type="dfn" id="dfn-presented-region">presented region</dfn> is a temporally active region that satisfies the following conditions:</p>
-
- <ol>
- <li>the computed value of <code>tts:opacity</code> is not equal to "0.0"; and</li>
-
- <li>the computed value of <code>tts:display</code> is not "none"; and</li>
-
- <li>the computed value of <code>tts:visibility</code> is not "hidden"; and</li>
-
- <li>either (a) content is selected into the region or (b) the computed value of <code>tts:showBackground</code> is equal
- to "always" and the computed value of <code>tts:backgroundColor</code> has non-transparent alpha.</li>
- </ol>
- </section>
-
- <section id="dimensions-and-position" typeof="bibo:Chapter" resource="#dimensions-and-position" property="bibo:hasPart">
- <h4 id="h-dimensions-and-position" resource="#h-dimensions-and-position"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.8.2 </span>Dimensions and Position</span></h4>
-
- <p>All regions <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> extend beyond 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 <a data-lt="presented region" href="#dfn-presented-region" class="internalDFN" data-link-type="dfn">presented regions</a> in a given <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> <em class="rfc2119" title="SHALL">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" typeof="bibo:Chapter" resource="#maximum-number" property="bibo:hasPart">
- <h4 id="h-maximum-number" resource="#h-maximum-number"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.8.3 </span>Maximum number</span></h4>
-
- <p>The number of <a data-lt="presented region" href="#dfn-presented-region" class="internalDFN" data-link-type="dfn">presented regions</a> in a given <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be greater than 4.</p>
- </section>
- </section>
-
- <section id="hypothetical-render-model-1" typeof="bibo:Chapter" resource="#hypothetical-render-model-1" property="bibo:hasPart">
- <h3 id="h-hypothetical-render-model-1" resource="#h-hypothetical-render-model-1"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.9 </span>Hypothetical Render Model</span></h3>
-
- <p>It <em class="rfc2119" title="SHALL">SHALL</em> be possible to apply the Hypothetical Render Model specified in Section <a href="#hypothetical-render-model" class="sec-ref"><span class="secno">9.</span> <span class="sec-title">Hypothetical Render Model</span></a> to any sequence of consecutive <a data-lt="intermediate synchronic document" href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic documents</a> without error as defined in Section <a href="#hypothetical-render-model-general" class="sec-ref"><span class="secno">9.2</span> <span class="sec-title">General</span></a>.</p>
- </section>
-
- <section id="common-features" typeof="bibo:Chapter" resource="#common-features" property="bibo:hasPart">
- <h3 id="h-common-features" resource="#h-common-features"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.10 </span>Features</span></h3>
-
- <p>See <a href="#conformance" class="sec-ref"><span class="secno">4.</span> <span class="sec-title">Conformance</span></a> for a definition of "permitted" and "prohibited".</p>
-
- <table class="simple">
- <tbody>
- <tr>
- <th style="text-align:center">Feature</th>
-
- <th style="text-align:center">Disposition</th>
-
- <th style="text-align:center">Additional provision</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the TT Feature namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#animation</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#cellResolution</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#clockMode</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#content</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#core</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#display-block</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#display-inline</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#display-region</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#display</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#dropMode</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#extent-region</code></td>
-
- <td>permitted</td>
- <td>The <code>tts:extent</code> attribute <em class="rfc2119" title="SHALL">SHALL</em> be present on all <code>region</code> elements.</td>
- </tr>
-
- <tr>
- <td><code>#extent-root</code></td>
-
- <td>permitted</td>
- <td>If the <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> includes any length value that uses the <code>px</code> expression,
- <code>tts:extent</code> <em class="rfc2119" title="SHALL">SHALL</em> be present on the <code>tt</code> element.</td>
- </tr>
-
- <tr>
- <td><code>#extent</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#frameRate</code></td>
-
- <td>permitted</td>
- <td>If the <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> includes any clock time expression that uses the <code>frames</code> term or any offset
-time expression that uses the <code>f</code> metric, the <code>ttp:frameRate</code> attribute <em class="rfc2119" title="SHALL">SHALL</em>
-be present on the <code>tt</code> element.</td>
- </tr>
-
- <tr>
- <td><code>#frameRateMultiplier</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#layout</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-cell</code></td>
-
- <td>permitted</td>
- <td>'c' units <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be present outside of the value of <code>ebutts:linePadding</code>.</td>
- </tr>
-
- <tr>
- <td><code>#length-integer</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-negative</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-percentage</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-pixel</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-positive</code></td>
-
- <td>permitted</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#length-real</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#markerMode</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#metadata</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#opacity</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#origin</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#overflow</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#pixelAspectRatio</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#presentation</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#profile</code></td>
-
- <td>permitted</td>
-
- <td>
- <p>
-
- The <code>ttp:profile</code> attribute <em class="rfc2119" title="SHOULD">SHOULD</em> be present on the <code>tt</code> element and equal to the designator of the IMSC1 profile
- to which the document conforms; unless the document also conforms to [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>], in which case the <code>ttp:profile</code> attribute
- <em class="rfc2119" title="SHOULD NOT">SHOULD NOT</em> be present on the <code>tt</code> element, and instead the designator of the IMSC1 profile to which the document conforms and
- the URI "urn:ebu:tt:distribution:2014-01" <em class="rfc2119" title="SHOULD">SHOULD</em> each be carried in an <code>ebuttm:conformsToStandard</code> element as specified in
- [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>].
-
- </p>
-
- <p>The <code>ttp:profile</code> element <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be present.</p>
-
- </td>
- </tr>
-
- <tr>
- <td><code>#showBackground</code></td>
-
- <td>permitted</td>
-
-<td></td>
- </tr>
-
- <tr>
- <td><code>#structure</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-chained</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-inheritance-content</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-inheritance-region</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-inline</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-nested</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-referential</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#subFrameRate</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#tickRate</code></td>
-
- <td>permitted</td>
-
- <td><code>ttp:tickRate</code> <em class="rfc2119" title="SHALL">SHALL</em> be present on the <code>tt</code> element if the
- document contains any time expression that uses the <code>t</code> metric.</td>
-
- </tr>
-
- <tr>
- <td><code>#timeBase-clock</code></td>
-
- <td>prohibited</td>
-
-<td></td>
- </tr>
-
- <tr>
- <td><code>#timeBase-media</code></td>
-
- <td>permitted</td>
-
- <td>NOTE: [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] specifies that the default timebase is <code>"media"</code> if
- <code>ttp:timeBase</code> is not specified on <code>tt</code>.</td>
-
- </tr>
-
- <tr>
- <td><code>#timeBase-smpte</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-clock-with-frames</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-clock</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-offset-with-frames</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-offset-with-ticks</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-offset</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#timeContainer</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#timing</code></td>
-
- <td>permitted</td>
-<td>
- <ul class="short-list"><li>All time expressions within a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHOULD">SHOULD</em> use the same syntax, either
- <code>clock-time</code> or <code>offset-time</code>.</li>
-
- <li>For any content element that contains <code>br</code> elements or text nodes or a
- <code>smpte:backgroundImage</code> attribute, the <code>begin</code> and <code>end</code> attributes <em class="rfc2119" title="SHOULD">SHOULD</em>
- be specified on the content element or at least one of its ancestors.</li></ul>
- </td>
- </tr>
-
- <tr>
- <td><code>#transformation</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#visibility-block</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#visibility-region</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode-horizontal-lr</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode-horizontal-rl</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode-horizontal</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#zIndex</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <th style="text-align:center">Extension</th>
- <th style="text-align:center">Disposition</th>
- <th style="text-align:center">Provisions</th>
- </tr>
-
- <tr>
- <td style="text-align:center" colspan="3"><em>Relative to the IMSC 1.0 Extension namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#aspectRatio</code></td>
-
- <td>permitted</td>
-
-<td></td>
- </tr>
-
- <tr>
- <td><code>#forcedDisplay</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#progressivelyDecodable</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#altText</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
- </tbody>
- </table>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note13"><span>Note</span></div><p class="">As specified in [<cite><a class="bibref" href="#bib-TTML1">TTML1</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" typeof="bibo:Chapter" resource="#text-profile-constraints" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-text-profile-constraints" resource="#h-text-profile-constraints"><span property="xhv:role" resource="xhv:heading"><span class="secno">7. </span>Text Profile Constraints</span></h2>
-
- <section id="text-profile-designator" typeof="bibo:Chapter" resource="#text-profile-designator" property="bibo:hasPart">
- <h3 id="h-text-profile-designator" resource="#h-text-profile-designator"><span property="xhv:role" resource="xhv:heading"><span class="secno">7.1 </span>Profile Designator</span></h3>
-
- <p>This profile is associated with the following profile designator:</p>
-
- <table class="simple">
- <thead>
- <tr>
- <th>Profile Name</th>
-
- <th>Profile Designator</th>
- </tr>
- </thead>
-
- <tbody>
- <tr>
- <td>IMSC 1.0 Text</td>
-
- <td><code>http://www.w3.org/ns/ttml/profile/imsc1/text</code></td>
- </tr>
- </tbody>
- </table>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note14"><span>Note</span></div><p class="">As specified in <a href="#common-features" class="sec-ref"><span class="secno">6.10</span> <span class="sec-title">Features</span></a>, the presence of the <code>ttp:profile</code> attribute is
- not required by this profile. The profile designator specified above is intended to be generally used to signal conformance
- of a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> to the profile. The details of such signaling depends on the application, and can, for instance, use
- metadata structures out-of-band of the <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>.</p></div>
- </section>
-
- <section id="recommended-character-sets" typeof="bibo:Chapter" resource="#recommended-character-sets" property="bibo:hasPart">
- <h3 id="h-recommended-character-sets" resource="#h-recommended-character-sets"><span property="xhv:role" resource="xhv:heading"><span class="secno">7.2 </span>Recommended Character Sets</span></h3>
-
- <p>A <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHOULD">SHOULD</em> be authored using characters selected from the sets specified in <a href="#recommended-unicode-code-points-per-language" class="sec-ref"><span class="secno">B.</span> <span class="sec-title">Recommended Character Sets</span></a>.</p>
- </section>
-
- <section id="reference-fonts-1" typeof="bibo:Chapter" resource="#reference-fonts-1" property="bibo:hasPart">
- <h3 id="h-reference-fonts-1" resource="#h-reference-fonts-1"><span property="xhv:role" resource="xhv:heading"><span class="secno">7.3 </span>Reference Fonts</span></h3>
-
- <p>The flow of text within a region depends the dimensions and spacing (kerning) between individual glyphs.
- The following allows, for instance, region extents to be set such that text flows without clipping.</p>
-
- <p>When rendering codepoints matching one of the combinations of computed font family and codepoints listed in
- <a href="#reference-fonts" class="sec-ref"><span class="secno">A.</span> <span class="sec-title">Reference Fonts</span></a>, a processor <em class="rfc2119" title="SHALL">SHALL</em> use a font that generates a glyph sequence whose dimension is substantially
- identical to the glyph sequence that would have been generated by one of the specified reference fonts.</p>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note15"><span>Note</span></div><p class="">Implementations can use fonts other than those specified in <a href="#reference-fonts" class="sec-ref"><span class="secno">A.</span> <span class="sec-title">Reference Fonts</span></a>. Two fonts
- with equal metrics can have a different appearance, but flow identically.</p></div>
-
- </section>
-
- <section id="features" typeof="bibo:Chapter" resource="#features" property="bibo:hasPart">
- <h3 id="h-features" resource="#h-features"><span property="xhv:role" resource="xhv:heading"><span class="secno">7.4 </span>Features</span></h3>
-
- <p>See <a href="#conformance" class="sec-ref"><span class="secno">4.</span> <span class="sec-title">Conformance</span></a> for a definition of "permitted" and "prohibited".</p>
-
- <table class="simple">
- <tbody>
- <tr>
- <th style="text-align:center">Feature</th>
-
- <th style="text-align:center">Disposition</th>
-
- <th style="text-align:center">Additional provisions</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the TT Feature namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#backgroundColor-block</code></td>
-
- <td>permitted</td>
- <td></td>
- </tr>
-
- <tr>
- <td><code>#backgroundColor-inline</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#backgroundColor-region</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#backgroundColor</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#bidi</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#color</code></td>
-
- <td>permitted</td>
- <td>The initial value of <code>tts:color</code> <em class="rfc2119" title="SHALL">SHALL</em> be "white". NOTE: This is consistent with
- [<cite><a class="bibref" href="#bib-ST2052-1">ST2052-1</a></cite>].</td>
- </tr>
-
- <tr>
- <td><code>#direction</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#displayAlign</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#extent-region</code></td>
-
- <td>permitted</td>
- <td>When applied to a region element, the <code>tts:extent</code> attribute <em class="rfc2119" title="SHALL">SHALL</em> use <code>px</code> units or
- "percentage" representation, and <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> use <code>em</code> units.</td>
- </tr>
-
- <tr>
- <td><code>#fontFamily-generic</code></td>
-
- <td>permitted</td>
- <td>A <code>tts:fontFamily</code> of either <code>"monospaceSerif"</code> or <code>"proportionalSansSerif"</code> <em class="rfc2119" title="SHOULD">SHOULD</em> be
- specified for all presented text content. A tts:fontFamily of <code>"default"</code> <em class="rfc2119" title="SHALL">SHALL</em> be equivalent to <code>"monospaceSerif"</code>.</td>
- </tr>
-
- <tr>
- <td><code>#fontFamily-non-generic</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontFamily</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontSize-anamorphic</code></td>
-
- <td>prohibited</td>
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontSize-isomorphic</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontSize</code></td>
-
- <td></td><td>See <code>#fontSize-anamorphic</code> and <code>#fontSize-isomorphic</code>.</td>
- </tr>
-
- <tr>
- <td><code>#fontStyle-italic</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontStyle-oblique</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontStyle</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontWeight-bold</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontWeight</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#length-em</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#lineBreak-uax14</code></td>
-
- <td></td>
-
- <td>The <a href="#dfn-processor" class="internalDFN" data-link-type="dfn">processor</a> <em class="rfc2119" title="SHALL">SHALL</em> implement the <code>#lineBreak-uax14</code> feature defined in the TT Feature namespace.</td>
- </tr>
-
- <tr>
- <td><code>#lineHeight</code></td>
-
- <td>permitted</td>
- <td><code><length></code> <em class="rfc2119" title="SHOULD">SHOULD</em> be explicitly specified as there is no uniform implementation of the "normal" value
- at the time of this writing.</td>
- </tr>
-
- <tr>
- <td><code>#nested-div</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#nested-span</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#origin</code></td>
-
- <td>permitted</td>
- <td>The <code>tts:origin</code> attribute <em class="rfc2119" title="SHALL">SHALL</em> use <code>px</code> units or "percentage" representation, and <em class="rfc2119" title="SHALL NOT">SHALL NOT</em>
- use <code>em</code> units.</td>
- </tr>
-
- <tr>
- <td><code>#padding-1</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#padding-2</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#padding-3</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#padding-4</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#padding</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textAlign-absolute</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textAlign-relative</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textAlign</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration-over</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration-through</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration-under</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textOutline-blurred</code></td>
-
- <td>prohibited</td>
-
-<td></td>
- </tr>
-
- <tr>
- <td><code>#textOutline-unblurred</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textOutline</code></td>
-
- <td>permitted</td>
- <td>If specified, the border thickness <em class="rfc2119" title="SHALL">SHALL</em> be 10% or less than the associated font size.</td>
- </tr>
-
- <tr>
- <td><code>#unicodeBidi</code></td>
-
- <td>permitted</td><td></td>
- </tr>
- <tr>
- <td><code>#visibility</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
-
- <tr>
- <td><code>#visibility-inline</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
- <tr>
- <td><code>#wrapOption</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode-vertical</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <th style="text-align:center">Extension</th>
-
- <th style="text-align:center">Disposition</th>
-
- <th style="text-align:center">Provisions</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the SMPTE-TT Extension Namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#image</code></td>
-
- <td>prohibited</td>
-
-
-<td></td>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the IMSC 1.0 Extension namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#linePadding</code></td>
-
- <td>permitted</td>
-
- <td>
-
- <p>If used, the attribute <code>ebutts:linePadding</code> <em class="rfc2119" title="MAY">MAY</em> be specified on elements <code>region</code>, <code>body</code>,
- <code>div</code> and <code>p</code> in addition to <code>style</code>.</p>
-
- <p>The <a href="#dfn-processor" class="internalDFN" data-link-type="dfn">processor</a>:
- </p><ul class="short-list">
- <li><em class="rfc2119" title="SHALL">SHALL</em> apply <code>ebutts:linePadding</code> to <code>p</code> only; and</li>
- <li><em class="rfc2119" title="SHALL">SHALL</em> treat <code>ebutts:linePadding</code> as inheritable.</li>
- </ul>
- <p></p>
-
-
- </td>
- </tr>
-
- <tr>
- <td><code>#multiRowAlign</code></td>
-
- <td>permitted</td>
-
- <td>
- <p>If used, the attribute <code>ebutts:multiRowAlign</code> <em class="rfc2119" title="MAY">MAY</em> be specified on elements <code>region</code>, <code>body</code>,
- <code>div</code> and <code>p</code> in addition to <code>style</code></p>
-
- <p>The <a href="#dfn-processor" class="internalDFN" data-link-type="dfn">processor</a>:
- </p><ul class="short-list">
- <li><em class="rfc2119" title="SHALL">SHALL</em> apply <code>ebutts:multiRowAlign</code> to <code>p</code> only; and</li>
- <li><em class="rfc2119" title="SHALL">SHALL</em> treat <code>ebutts:multiRowAlign</code> as inheritable.</li>
- </ul>
- <p></p>
- </td>
- </tr>
- </tbody>
- </table>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note16"><span>Note</span></div><p class="">In contrast to this specification, [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>] specifies that the attributes <code>ebutts:linePadding</code> and <code>ebutts:multiRowAlign</code> are allowed only on the <code>style</code> element.</p></div>
-
- </section>
- </section>
-
- <section id="image-profile-constraints" typeof="bibo:Chapter" resource="#image-profile-constraints" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-image-profile-constraints" resource="#h-image-profile-constraints"><span property="xhv:role" resource="xhv:heading"><span class="secno">8. </span>Image Profile Constraints</span></h2>
-
- <section id="image-profile-designator" typeof="bibo:Chapter" resource="#image-profile-designator" property="bibo:hasPart">
- <h3 id="h-image-profile-designator" resource="#h-image-profile-designator"><span property="xhv:role" resource="xhv:heading"><span class="secno">8.1 </span>Profile Designator</span></h3>
-
- <p>This profile is associated with the following profile designator:</p>
-
- <table class="simple">
- <tbody>
- <tr>
- <th>Profile Name</th>
-
- <th>Profile Designator</th>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Image</td>
-
- <td><code>http://www.w3.org/ns/ttml/profile/imsc1/image</code></td>
- </tr>
- </tbody>
- </table>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note17"><span>Note</span></div><p class="">As specified in <a href="#common-features" class="sec-ref"><span class="secno">6.10</span> <span class="sec-title">Features</span></a>, the presence of the <code>ttp:profile</code> attribute is
- not required by this profile. The profile designator specified above is intended to be generally used to signal conformance
- of a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> to the profile. The details of such signaling depends on the application, and can, for instance, use
- metadata structures out-of-band of the <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>.</p></div>
- </section>
-
- <section id="presented-image" typeof="bibo:Chapter" resource="#presented-image" property="bibo:hasPart">
- <h3 id="h-presented-image" resource="#h-presented-image"><span property="xhv:role" resource="xhv:heading"><span class="secno">8.2 </span>Presented Image</span></h3>
-
- <section id="definition" typeof="bibo:Chapter" resource="#definition" property="bibo:hasPart">
- <h4 id="h-definition" resource="#h-definition"><span property="xhv:role" resource="xhv:heading"><span class="secno">8.2.1 </span>Definition</span></h4>
-
- <p>A <dfn data-dfn-type="dfn" id="dfn-presented-image">presented image</dfn> is a <code>div</code> element with a <code>smpte:backgroundImage</code> attribute that does
- not extend beyond a <a href="#dfn-presented-region" class="internalDFN" data-link-type="dfn">presented region</a>.</p>
- </section>
-
- <section id="number-per-region" typeof="bibo:Chapter" resource="#number-per-region" property="bibo:hasPart">
- <h4 id="h-number-per-region" resource="#h-number-per-region"><span property="xhv:role" resource="xhv:heading"><span class="secno">8.2.2 </span>Number per Region</span></h4>
-
- <p>In a given synchronic document, there shall be at most one <a href="#dfn-presented-image" class="internalDFN" data-link-type="dfn">presented image</a> per <a href="#dfn-presented-region" class="internalDFN" data-link-type="dfn">presented region</a>.</p>
-
- </section>
- </section>
-
- <section id="div-element" typeof="bibo:Chapter" resource="#div-element" property="bibo:hasPart">
- <h3 id="h-div-element" resource="#h-div-element"><span property="xhv:role" resource="xhv:heading"><span class="secno">8.3 </span><code>div</code> element</span></h3>
-
- <p>If a <code>smpte:backgroundImage</code> attribute is applied to a <code>div</code> element:
-
- </p><ul>
- <li>the width and height of the image source referenced by <code>smpte:backgroundImage</code> <em class="rfc2119" title="SHALL">SHALL</em> be equal to width and height of the extent of the region in which the <code>div</code> element is presented;</li>
-
- <li>the <code>div</code> element <em class="rfc2119" title="SHOULD">SHOULD</em> contain a <code>metadata</code> element containing an <code>ittm:altText</code> element that is a <a href="#dfn-text-alternative" class="internalDFN" data-link-type="dfn">text alternative</a> of the image referenced by the <code>smpte:backgroundImage</code> attribute; and</li>
-
- <li>The <code>smpte:backgroundImage</code> attribute <em class="rfc2119" title="SHALL">SHALL</em> reference a PNG datastream as specified in [<cite><a class="bibref" href="#bib-PNG">PNG</a></cite>]. If a pHYs chunk is present, it <em class="rfc2119" title="SHALL">SHALL</em> indicate square pixels. Note:
- If no pixel aspect ratio is carried, the default of square pixels is assumed.<br></li>
- </ul>
-
- <p></p>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note18"><span>Note</span></div><p class="">In [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>], <code>tts:extent</code> and <code>tts:origin</code> do not apply to <code>div</code> elements. In order to individually position multiple <code>div</code> elements, each <code>div</code> can be associated with a distinct <code>region</code> with the desired <code>tts:extent</code> and <code>tts:origin</code>.</p></div>
- </section>
-
- <section id="features-1" typeof="bibo:Chapter" resource="#features-1" property="bibo:hasPart">
- <h3 id="h-features-1" resource="#h-features-1"><span property="xhv:role" resource="xhv:heading"><span class="secno">8.4 </span>Features</span></h3>
-
- <p>See <a href="#conformance" class="sec-ref"><span class="secno">4.</span> <span class="sec-title">Conformance</span></a> for a definition of "permitted" and "prohibited".</p>
-
- <table class="simple">
- <tbody>
- <tr>
- <th style="text-align:center">Feature</th>
-
- <th style="text-align:center">Disposition</th>
-
- <th style="text-align:center">Additional provisions</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the TT Feature namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#bidi</code></td>
-
- <td></td>
-
- <td>See implied features: some are prohibited, others are permitted.</td>
- </tr>
-
- <tr>
- <td><code>#color</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#content</code></td>
-
- <td>permitted</td>
-
- <td>The <code>p</code>, <code>span</code> and <code>br</code> elements <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be present.</td>
- </tr>
-
- <tr>
- <td><code>#direction</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#displayAlign</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontFamily</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontSize</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontStyle</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontWeight</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#length-em</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#lineBreak-uax14</code></td>
-
- <td></td>
-
- <td>No processor requirement is specified.</td>
- </tr>
-
- <tr>
- <td><code>#lineHeight</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#nested-div</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#nested-span</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#padding</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#textAlign</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#textOutline</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#unicodeBidi</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#visibility</code></td>
-<td></td>
- <td>See implied features: some are prohibited, others are permitted.</td>
-
- </tr>
-
-
- <tr>
- <td><code>#visibility-inline</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#wrapOption</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode</code></td>
-
- <td></td>
-
- <td>See implied features: some are prohibited, others are permitted.</td>
-
- </tr>
-
- <tr>
- <td><code>#writingMode-vertical</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <th style="text-align:center">Extension</th>
- <th style="text-align:center">Disposition</th>
- <th style="text-align:center">Provisions</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the SMPTE-TT Extension namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#image</code></td>
-
- <td>permitted</td>
-
- <td><ul class="short-list">
- <li><code>smpte:backgroundImage</code> <em class="rfc2119" title="MAY">MAY</em> be used.</li>
- <li><code>smpte:backgroundImageHorizontal</code> and <code>smpte:backgroundImageVertical</code> <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.</li>
- <li><code>smpte:image</code> <em class="rfc2119" title="SHALL NOT">SHALL NOT</em> be used.</li></ul></td>
- </tr>
- </tbody>
- </table>
- </section>
- </section>
-
- <section id="hypothetical-render-model" typeof="bibo:Chapter" resource="#hypothetical-render-model" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-hypothetical-render-model" resource="#h-hypothetical-render-model"><span property="xhv:role" resource="xhv:heading"><span class="secno">9. </span>Hypothetical Render Model</span></h2>
-
- <section id="overview-non-normative" typeof="bibo:Chapter" resource="#overview-non-normative" property="bibo:hasPart">
-
- <h3 id="h-overview-non-normative" resource="#h-overview-non-normative"><span property="xhv:role" resource="xhv:heading"><span class="secno">9.1 </span>Overview (non-normative)</span></h3>
-
- <p>This Section specifies the Hypothetical Render Model illustrated in <a href="#fig-hypothetical-render-model" class="fig-ref">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 <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> complexity. It is not intended as a specification of the
- processing requirements for implementations. 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 neither requires the implementation of such a
- buffer, nor models the sub-pixel character positioning and anti-aliased glyph rendering that can be used to produce text
- output.</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 <a data-lt="intermediate synchronic document" href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic documents</a>
- obtained from an input <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>, and uses a simple double buffering model: while an <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic
- document</a> E<sub>n</sub> is being painted into Presentation Buffer P<sub>n</sub> (the "front buffer" of the model), the
- previous <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> 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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a>
- 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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a>
- E<sub>n</sub> completes before the end of <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> 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 <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a> resolution.</p>
-
- <p>To enable scenarios where the same glyphs are used in multiple successive <a data-lt="intermediate synchronic document" href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic documents</a>, e.g. to convey a CEA-608/708-style roll-up (see
- [<cite><a class="bibref" href="#bib-CEA-608">CEA-608</a></cite>] and [<cite><a class="bibref" href="#bib-CEA-708">CEA-708</a></cite>]), the Glyph Buffers G<sub>n</sub> and G<sub>n-1</sub> store rendered glyphs across <a data-lt="intermediate synchronic document" href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic documents</a>, 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="hypothetical-render-model-general" typeof="bibo:Chapter" resource="#hypothetical-render-model-general" property="bibo:hasPart">
- <h3 id="h-hypothetical-render-model-general" resource="#h-hypothetical-render-model-general"><span property="xhv:role" resource="xhv:heading"><span class="secno">9.2 </span>General</span></h3>
-
- <p>The Presentation Compositor <em class="rfc2119" title="SHALL">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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>0</sub> for the which the pixels
- of P<sub>0</sub> <em class="rfc2119" title="SHALL">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 class="rfc2119" title="SHALL">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; or</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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub> in the
- Presentation Buffer P<sub>n</sub> <em class="rfc2119" title="SHALL">SHALL</em> be:</p>
-
- <p class="equation">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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>, as
- specified in <a href="#paint-regions" class="sec-ref"><span class="secno">9.3</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 href="#paint-text" class="sec-ref"><span class="secno">9.5</span> <span class="sec-title">Paint Text</span></a>; and
- </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 href="#paint-images">.</a>
- </li>
- </ul>
-
- <p>The contents of the Presentation Buffer P<sub>n</sub> <em class="rfc2119" title="SHALL">SHALL</em> be transferred instantaneously to Presentation Buffer
- P<sub>n-1</sub> at the presentation time of <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>, making the latter
- available for display.</p>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note19"><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 <a href="#dfn-related-video-object" class="internalDFN" data-link-type="dfn">Related Video Object</a>.</p></div>
-
- <p>It <em class="rfc2119" title="SHALL">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 class="rfc2119" title="SHALL">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 class="note-title" aria-level="4" role="heading" id="h-note20"><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 class="note-title" aria-level="4" role="heading" id="h-note21"><span>Note</span></div><p class="">IPD effectively sets a limit on the complexity of any given <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a>.</p></div>
- </section>
-
- <section id="paint-regions" typeof="bibo:Chapter" resource="#paint-regions" property="bibo:hasPart">
- <h3 id="h-paint-regions" resource="#h-paint-regions"><span property="xhv:role" resource="xhv:heading"><span class="secno">9.3 </span>Paint Regions</span></h3>
-
- <p>The total normalized drawing area S(E<sub>n</sub>) for <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub> <em class="rfc2119" title="SHALL">SHALL</em>
- be</p>
-
- <p class="equation">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 class="note-title" aria-level="4" role="heading" id="h-note22"><span>Note</span></div><p class="">To ensure consistency of the Presentation Buffer, a new <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> requires
- clearing of the root container.</p></div>
-
- <p>PAINT(E<sub>n</sub>) <em class="rfc2119" title="SHALL">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 class="equation">PAINT(E<sub>n</sub>) = ∑<sub>R<sub>i</sub>∈R<sub>p</sub></sub> NSIZE(R<sub>i</sub>) ∙ NBG(R<sub>i</sub>)</p>
-
- <p>where R_p <em class="rfc2119" title="SHALL">SHALL</em> be the set of <a data-lt="presented region" href="#dfn-presented-region" class="internalDFN" data-link-type="dfn">presented regions</a> in the <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic
- document</a> E<sub>n</sub>.</p>
-
- <p>NSIZE(R<sub>i</sub>) <em class="rfc2119" title="SHALL">SHALL</em> be given by:</p>
-
- <p class="equation">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 6</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 class="rfc2119" title="SHALL">SHALL</em> be the total number of <code>tts:backgroundColor</code> attributes associated with the given
- region R<sub>i</sub> in the <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a>. 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; or</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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> (see [<cite><a class="bibref" href="#bib-TTML1">TTML1</a></cite>] for more
- details on when a content element is followed into a region); or
- </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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> (see [<cite><a class="bibref" href="#bib-TTML1">TTML1</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 class="rfc2119" title="SHALL">SHALL</em> require an additional fill operation for all
- region pixels.</p>
- </section>
-
- <section id="paint-images" typeof="bibo:Chapter" resource="#paint-images" property="bibo:hasPart">
- <h3 id="h-paint-images" resource="#h-paint-images"><span property="xhv:role" resource="xhv:heading"><span class="secno">9.4 </span>Paint Images</span></h3>
-
- <p>The Presentation Compositor <em class="rfc2119" title="SHALL">SHALL</em> paint into the Presentation Buffer P<sub>n</sub> all visible pixels of presented
- images of <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>.</p>
-
- <p>For each <a href="#dfn-presented-image" class="internalDFN" data-link-type="dfn">presented image</a>, the Presentation Compositor <em class="rfc2119" title="SHALL">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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">
- intermediate synchronic document</a> E<sub>n-1</sub>, copy using the Image Copier the image 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 class="rfc2119" title="SHALL">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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a>
- E<sub>n</sub> in the Presentation Buffer <em class="rfc2119" title="SHALL">SHALL</em> be as follows:</p>
-
- <p class="equation">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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>;
- </li>
-
- <li>I<sub>d</sub> is the set of images decoded when painting <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>;
- </li>
-
- <li>IDec is the image decoding rate; and</li>
-
- <li>ICpy is the normalized image copy performance factor.</li>
- </ul>
-
- <p>NRGA(I<sub>i</sub>) is the Normalized Image Area of <a href="#dfn-presented-image" class="internalDFN" data-link-type="dfn">presented image</a> I<sub>i</sub> and <em class="rfc2119" title="SHALL">SHALL</em> be equal to:</p>
-
- <p class="equation">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 class="rfc2119" title="SHALL">SHALL</em> be the number of pixels of <a href="#dfn-presented-image" class="internalDFN" data-link-type="dfn">presented image</a> I<sub>i</sub>.</p>
-
- <p>The contents of the Decoded Image Buffer D<sub>n</sub> <em class="rfc2119" title="SHALL">SHALL</em> be transferred instantaneously to Decoded Image Buffer
- D<sub>n-1</sub> at the presentation time of <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> 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 class="rfc2119" title="SHALL">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 class="rfc2119" title="SHALL">SHALL</em> be the Normalized Decoded Image Buffer Size
- (NDIBS).</p>
-
- <p>Unless specified otherwise, the following table <em class="rfc2119" title="SHALL">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" typeof="bibo:Chapter" resource="#paint-text" property="bibo:hasPart">
- <h3 id="h-paint-text" resource="#h-paint-text"><span property="xhv:role" resource="xhv:heading"><span class="secno">9.5 </span>Paint Text</span></h3>
-
- <p>In the context of this section, a <dfn data-dfn-type="dfn" id="dfn-glyph">glyph</dfn> is a tuple consisting of (i) one character and (ii) the computed values of the following
- style properties:
-
- </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>
-
- <p></p>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note23"><span>Note</span></div><p class="">In complex scripts, the mapping from character to typographical glyph is not one-to-one. For instance, a given arabic character can
- yield multiple glyphs depending on its position in a word. The Hypothetical Render Model however assumes a one-to-one mapping
- and accounts for complex scripts by reducing the performance of the glyph buffer.</p></div>
-
- <p>For each <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> associated with a character in a <a href="#dfn-presented-region" class="internalDFN" data-link-type="dfn">presented region</a> of <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>,
- the Presentation Compositor <em class="rfc2119" title="SHALL">SHALL</em>:</p>
-
- <ul>
- <li>if an identical <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> is present in Glyph Buffer G<sub>n</sub>, copy the <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> 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 <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> is present in Glyph Buffer G<sub>n-1</sub>, i.e. an identical <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> was present in <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate
- synchronic document</a> E<sub>n-1</sub>, copy using the Glyph Copier the <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> 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 <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> into the Presentation Buffer P<sub>n</sub> and Glyph Buffer
- G<sub>n</sub>.</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 rendering the text of an <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a>
- E<sub>n</sub> in the Presentation Buffer is as follows:</p>
-
- <p class="equation">DUR<sub>T</sub>(E<sub>n</sub>) = ∑<sub>g<sub>i</sub> ∈ Γ<sub>r</sub></sub> NRGA(g<sub>i</sub>) / Ren(g<sub>i</sub>)
- + ∑<sub>g<sub>j</sub> ∈ Γ<sub>c</sub></sub> NRGA(g<sub>j</sub>) / GCpy</p>
-
- <p>where</p>
-
- <ul>
- <li>Γ<sub>r</sub> is the set of <a data-lt="glyph" href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyphs</a> rendered into the Presentation Buffer P<sub>n</sub> using the Glyph Renderer in
- <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>;
- </li>
-
- <li>Γ<sub>c</sub> is the set of <a data-lt="glyph" href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyphs</a> copied to the Presentation Buffer P<sub>n</sub> using the Glyph Copier in
- <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>;
- </li>
-
- <li>Ren(g<sub>i</sub>) is the text rendering performance factor for <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> g<sub>i</sub>; and</li>
-
- <li>GCpy is the normalized glyph copy performance factor.</li>
- </ul>
-
- <p>The Normalized Rendered Glyph Area NRGA(g<sub>i</sub>) of a <a href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyph</a> g<sub>i</sub> <em class="rfc2119" title="SHALL">SHALL</em> be equal to:</p>
-
- <p class="equation">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 class="rfc2119" title="SHALL">SHALL</em> be copied instantaneously to Glyph Buffer G<sub>n-1</sub> at the
- presentation time of <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> E<sub>n</sub>.</p>
-
- <p>It <em class="rfc2119" title="SHALL">SHALL</em> be an error for the sum of NRGA(g<sub>i</sub>) over all <a data-lt="glyph" href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyphs</a> Glyph Buffer G<sub>n</sub> to be larger
- than the Normalized Glyph Buffer Size (NGBS).</p>
-
- <p>Unless specified otherwise, the following table specifies values of GCpy, Ren and NGBS.</p>
-
- <table class="simple">
- <thead>
- <tr>
- <th style="text-align: center;">Parameter</th>
-
- <th style="text-align: center;">Condition</th>
-
- <th style="text-align: center;">Initial value</th>
- </tr>
- </thead>
-
- <tbody>
- <tr>
- <td rowspan="2">Normalized glyph copy performance factor (GCpy)</td>
-
- <td>The character of g<sub>i</sub> belongs to a simple script as specified in <a href="#simple-scripts" class="sec-ref"><span class="secno">H.</span> <span class="sec-title">Simple Scripts</span></a></td>
-
- <td>12</td>
- </tr>
-
- <tr>
-
- <td>otherwise</td>
-
- <td>3</td>
- </tr>
-
- <tr>
- <td rowspan="2">Text rendering performance factor Ren(G<sub>i</sub>)</td>
- <td>The character of g<sub>i</sub> belongs to the CJK Unified Ideograph block as specified in [<cite><a class="bibref" href="#bib-UNICODE">UNICODE</a></cite>]</td>
-
- <td>0.6</td>
- </tr>
-
- <tr>
- <td>otherwise</td>
-
- <td>1.2</td>
- </tr>
-
- <tr>
- <td colspan="2">Normalized Glyph Buffer Size (NGBS)</td>
-
- <td>1</td>
- </tr>
- </tbody>
- </table>
-
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h-note24"><span>Note</span></div><p class="">NRGA(G<sub>i</sub>) does not take into account decorations (e.g. underline), effects (e.g.
- outline) or actual typographical 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 7</span></div>
- Setting a Normalized Glyph Buffer Size effectively sets a limit on the total number of distinct <a data-lt="glyph" href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyphs</a> present in any
- given <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a> 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 font size relative to the root container height is 1/15 , and
- the maximum number of distinct glyphs that can be buffered is 1÷(1÷15)^2=225 glyphs.
- </aside>
-
- <aside class="example"><div class="example-title"><span>Example 8</span></div>
- GCpy effectively sets a limit on animating text. 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 <a href="#dfn-intermediate-synchronic-document" class="internalDFN" data-link-type="dfn">intermediate synchronic document</a>), a GCpy and BDraw of 12 s-1
- would mean that a group of 160 <a data-lt="glyph" href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyphs</a> 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 9</span></div>
- Ren(G<sub>i</sub>) effectively sets a limit on the text 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 <a data-lt="glyph" href="#dfn-glyph" class="internalDFN" data-link-type="dfn">glyphs</a> 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>
-
-
- <section class="appendix" id="reference-fonts" typeof="bibo:Chapter" resource="#reference-fonts" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-reference-fonts" resource="#h-reference-fonts"><span property="xhv:role" resource="xhv:heading"><span class="secno">A. </span>Reference Fonts</span></h2>
-
-
-
- <table class="simple">
- <thead>
- <tr>
- <th>Computed Font Family</th>
-
- <th>Code Points</th>
-
- <th>Reference Font</th>
- </tr>
- </thead>
-
- <tbody>
- <tr>
- <td><code>monospaceSerif</code></td>
-
- <td>
- All code points specified in <a href="#recommended-unicode-code-points-per-language" class="sec-ref"><span class="secno">B.</span> <span class="sec-title">Recommended Character Sets</span></a>
- </td>
-
- <td>
- <a href="http://www.microsoft.com/typography/fonts/family.aspx?FID=10">Courier New</a>
- or
- <a href="https://fedorahosted.org/liberation-fonts/">Liberation Mono</a>
- </td>
- </tr>
-
- <tr>
- <td><code>proportionalSansSerif</code></td>
-
- <td>
- All code points specified in <a href="#recommended-unicode-code-points-per-language" class="sec-ref"><span class="secno">B.</span> <span class="sec-title">Recommended Character Sets</span></a>, excluding the code points
- defined for Hebrew and Arabic scripts.
- </td>
-
- <td>
- <a href="http://www.microsoft.com/typography/fonts/family.aspx?FID=8">Arial</a> or <a href="http://www.linotype.com/en/526/Helvetica-family.html">Helvetica</a> or <a href="https://fedorahosted.org/liberation-fonts/">Liberation Sans</a>
- </td>
- </tr>
- </tbody>
- </table>
-
- </section>
-
-
- <section class="appendix" id="recommended-unicode-code-points-per-language" typeof="bibo:Chapter" resource="#recommended-unicode-code-points-per-language" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-recommended-unicode-code-points-per-language" resource="#h-recommended-unicode-code-points-per-language"><span property="xhv:role" resource="xhv:heading"><span class="secno">B. </span>Recommended Character Sets</span></h2>
-
- <p>When authoring textual content, authors are encouraged to select from sets of characters based on the language indicated
- using <code>xml:lang</code>. 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, an author <em class="rfc2119" title="SHOULD">SHOULD</em> choose characters from the set resulting from the union of the
- following sets:</p>
-
- <ul>
- <li>the main exemplar character set specified for the language in [<cite><a class="bibref" href="#bib-CLDR">CLDR</a></cite>] as well as any corresponding uppercase characters as specified in [<cite><a class="bibref" href="#bib-UNICODE">UNICODE</a></cite>]; and</li>
-
- <li>the punctuation exemplar character set specified for the language in [<cite><a class="bibref" href="#bib-CLDR">CLDR</a></cite>];</li>
-
- <li>the digits and symbols included in all numberSystems specified for the language in [<cite><a class="bibref" href="#bib-CLDR">CLDR</a></cite>];</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>
- </ul>
-
- <p>Some of these sets overlap.</p>
-
- <p>Table 1 captures the set of characters intended to be available to authors across all languages. The terms used in the table
- are defined in [<cite><a class="bibref" href="#bib-UNICODE">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</td>
- </tr>
-
- <tr>
- <th>(Latin-1 Supplement)</th>
- </tr>
-
- <tr>
- <td>U+00A0 - U+00FF</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>(Latin Extended-B)</th>
- </tr>
-
- <tr>
- <td>U+0192 : LATIN SMALL LETTER F WITH HOOK</td>
- </tr>
-
- <tr>
- <th>(Spacing Modifier Letters)</th>
- </tr>
-
- <tr>
- <td>U+02DC : SMALL TILDE</td>
- </tr>
-
- <tr>
- <th>(Combining Diacritical Marks)</th>
- </tr>
-
- <tr>
- <td>U+0301 : COMBINING ACUTE ACCENT</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>(Currency symbols)</th>
- </tr>
-
- <tr>
- <td>U+20AC : EURO SIGN</td>
- </tr>
-
- <tr>
- <th>(Letterlike Symbols)
- </th></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>(Number Forms)</th>
- </tr>
-
- <tr>
- <td>U+2153 - U+215F : Fractions</td>
- </tr>
-
- <tr>
- <th>(Mathematical Operators)</th>
- </tr>
-
- <tr>
- <td>U+2212 : MINUS SIGN</td>
- </tr>
-
- <tr>
- <td>U+221E : INFINITY</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>(Block Elements)</th>
- </tr>
-
- <tr>
- <td>U+2588 : FULL BLOCK</td>
- </tr>
-
- <tr>
- <th>(Geometric Shapes)</th>
- </tr>
-
- <tr>
- <td>U+25A1 : WHITE SQUARE</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>
-
- </tbody></table><br>
-
- <p>Table 2 specifies supplementary character set that have proven useful in captioning and subtitling applications for a number
- of selected languages. Table 2 is non-exhaustive, and will be extended as needs arise.</p>
-
- <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>sq, fi, da, nl, en, de, is, no, sv, ca, fr, it</td>
-
- <td><em>no supplementary characters</em></td>
- </tr>
-
- <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>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+0308<br>
- (Greek and Coptic)<br>
- U+0386 - U+038A<br>
- U+038C<br>
- U+038E - U+03A1<br>
- U+03A3 - 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+0609<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, uk</td>
-
- <td>(Latin Extended-A)<br>
- U+0100 - U+017F<br>
-
- (Spacing Modifier Letters)<br>
- U+02BC<br>
-
- (Cyrillic)<br>
- U+0400 - U+045F<br>
- U+048A - U+04F9<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+048A - U+04F9</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 class="appendix" id="forced-content" typeof="bibo:Chapter" resource="#forced-content" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-forced-content" resource="#h-forced-content"><span property="xhv:role" resource="xhv:heading"><span class="secno">C. </span>Forced content (non-normative)</span></h2>
-
- <p><a href="#fig-forced-content" class="fig-ref">Fig. <span class="figno">3</span> <span class="fig-title">
- Illustration of the use of itts:forcedDisplay
- </span></a> below illustrates the use of forced content, i.e. <code>itts:forcedDisplay</code> and
- <code>displayForcedOnlyMode</code>. The content with <code>itts:forcedDisplay</code>="true" is the French translation of the
- "High School" sign. The content with <code>itts:forcedDisplay</code>="false" are French subtitles capturing a voiceover.</p>
-
- <figure id="fig-forced-content">
- <img src="forced-example-figure-1.png" alt="Illustration of the use of itts:forcedDisplay">
-
- <figcaption>Fig. <span class="figno">3</span> <span class="fig-title">
- Illustration of the use of itts:forcedDisplay
- </span></figcaption>
- </figure>
-
- <p>When the user selects French as the playback language but does not select French subtitles,
- <code>displayForcedOnlyMode</code> is set to "true", causing the display of the sign translation, which is useful to any French
- speaker, but hiding the voiceover subtitles as the voiceover is heard in French.</p>
-
- <p>If the user selects French as the playback language and also selects French subtitles, e.g. if the user is hard-of-hearing,
- <code>displayForcedOnlyMode</code> is set to "false", causing the display of both the sign translation and the voiceover
- subtitles.</p>
-
- <p>The algorithm for setting the <code>displayForcedOnlyMode</code> parameter and selecting the appropriate combination of
- subtitle and audio tracks depends on the application.</p>
- </section>
-
- <section class="appendix" id="wcag-applications" typeof="bibo:Chapter" resource="#wcag-applications" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-wcag-applications" resource="#h-wcag-applications"><span property="xhv:role" resource="xhv:heading"><span class="secno">D. </span>WCAG Considerations</span></h2>
-
- <p>In order to meet the guidelines in [<cite><a class="bibref" href="#bib-WCAG20">WCAG20</a></cite>], the following considerations apply.</p>
-
- <p>Guideline 1.1 of [<cite><a class="bibref" href="#bib-WCAG20">WCAG20</a></cite>] recommends that an implementation provide text alternatives for all non-text content. In the
- context of this specification, this text alternative is intended primarily to support users of the subtitles who cannot see
- images. Since the images of an <a href="#dfn-image-profile" class="internalDFN" data-link-type="dfn">Image Profile</a> <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> usually represent subtitle or caption text, the
- guidelines for authoring text equivalent strings given at <span class="sec-no">Images of text</span> of [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>] are
- appropriate.</p>
-
- <p>Thus, for each subtitle in an <a href="#dfn-image-profile" class="internalDFN" data-link-type="dfn">Image Profile</a> <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>, a text equivalent content in a <a href="#dfn-text-profile" class="internalDFN" data-link-type="dfn">Text Profile</a>
- <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> <em class="rfc2119" title="SHOULD">SHOULD</em> be written so that it conveys all essential content and fulfills the same function as the
- corresponding subtitle image. In the context of subtitling and captioning, this content will be (as a minimum) the verbatim
- equivalent of the image without précis or summarization. However, the author <em class="rfc2119" title="MAY">MAY</em> include extra information to the text
- equivalent string in cases where styling is applied to the text image with a deliberate connotation, as a <em>functional</em>
- replacement for the applied style.</p>
-
- <p>For instance, in subtitling and captioning, italics can be used to indicate an off screen speaker context (for example a
- voice from a radio). An author can choose to include this functional information in the text equivalent; for example, by
- including the word "Radio: " before the image equivalent text. Note that images in an <a href="#dfn-image-profile" class="internalDFN" data-link-type="dfn">Image Profile</a>
- <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a> that are intended for use as <em>captions</em>, i.e. intended for a hard of hearing audience, might already
- include this functional information in the rendered text.</p>
-
- <p>Guideline 1.1 of [<cite><a class="bibref" href="#bib-WCAG20">WCAG20</a></cite>] also recommends that accessible text alternatives must be "programmatically determinable." This
- means that the text must be able to be read and used by the assistive technologies (and the accessibility features in browsers)
- that people with disabilities use. It also means that the user must be able to use their assistive technology to find the
- alternative text (that they can use) when they land on the non-text content (that they can't use).</p>
- </section>
-
- <section class="appendix" id="sample-instance" typeof="bibo:Chapter" resource="#sample-instance" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-sample-instance" resource="#h-sample-instance"><span property="xhv:role" resource="xhv:heading"><span class="secno">E. </span>Sample Document Instance (non-normative)</span></h2>
-
- <p>The following sample <a data-lt="Document Instance" href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instances</a> conforms to the Text and Image Profiles, respectively. These samples are for illustration only, and are neither intended to capture current or future practice, nor exercise all normative prose contained in this specification.</p>
-
-<div class="example"><div class="example-title"><span>Example 10</span></div><pre class="example"><?xml version="1.0" encoding="UTF-8"?>
-<tt
- xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
- xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
- xmlns:tts="http://www.w3.org/ns/ttml#styling"
- xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
- xmlns:ittp="http://www.w3.org/ns/ttml/profile/imsc1#parameter"
- ittp:aspectRatio="4 3">
-
- <head>
- <layout>
- <region xml:id="area1" tts:origin="10% 10%" tts:extent="80% 10%" tts:backgroundColor="black" tts:displayAlign="center" tts:color="red"/>
- </layout>
- </head>
- <body>
- <div>
- <p region="area1" begin="0s" end="6s">Lorem ipsum dolor sit amet.</p>
- </div>
- </body>
-</tt></pre></div>
-
-
-<div class="example"><div class="example-title"><span>Example 11</span></div><pre class="example"><?xml version="1.0" encoding="UTF-8"?>
-<tt
- xmlns="http://www.w3.org/ns/ttml"
- xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
- xmlns:tts="http://www.w3.org/ns/ttml#styling"
- xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
- xmlns:smpte="http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt"
- xmlns:itts="http://www.w3.org/ns/ttml/profile/imsc1#styling"
- tts:extent="640px 480px"
- ttp:frameRate="25"
- xml:lang="fr">
-
- <head>
- <layout>
- <region xml:id="region1" tts:origin="120px 410px" tts:extent="240px 40px" tts:showBackground="whenActive"/>
- <region xml:id="region2" tts:origin="120px 20px" tts:extent="240px 40px" tts:showBackground="whenActive"/>
- </layout>
- </head>
- <body>
- <div region="region1" begin="00:00:01:00" end="00:00:02:00" smpte:backgroundImage="1.png"/>
- <div region="region1" begin="00:00:03:20" end="00:00:04:12" smpte:backgroundImage="2.png"/>
- <div region="region2" itts:forcedDisplay="true" begin="00:00:03:20" end="00:00:04:12" smpte:backgroundImage="3.png"/>
- </body>
-</tt>
-</pre></pre></div></section>
-
- <section class="appendix" id="features-and-extensions" typeof="bibo:Chapter" resource="#features-and-extensions" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-features-and-extensions" resource="#h-features-and-extensions"><span property="xhv:role" resource="xhv:heading"><span class="secno">F. </span>Extensions</span></h2>
-
- <section class="appendix" id="general-1" typeof="bibo:Chapter" resource="#general-1" property="bibo:hasPart">
- <h3 id="h-general-1" resource="#h-general-1"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.1 </span>General</span></h3>
-
- <p>The following sections define extension designations, expressed as relative URIs (fragment identifiers) relative to the
- IMSC 1.0 Extension Namespace base URI.</p>
- </section>
-
- <section class="appendix" id="progressivelydecodable" typeof="bibo:Chapter" resource="#progressivelydecodable" property="bibo:hasPart">
- <h3 id="h-progressivelydecodable" resource="#h-progressivelydecodable"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.2 </span>#progressivelyDecodable</span></h3>
-
- <p>A <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a> supports the <code>#progressivelyDecodable</code> feature if it recognizes and is
- capable of transforming values of the <a href="#ttp-progressivelyDecodable"><code>ittp:progressivelyDecodable</code></a>.</p>
-
- <p>A <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> supports the <code>#progressivelyDecodable</code> feature if it implements presentation
- semantic support for values of the <a href="#ttp-progressivelyDecodable"><code>ittp:progressivelyDecodable</code></a>
- attribute.</p>
- </section>
-
- <section class="appendix" id="aspectratio" typeof="bibo:Chapter" resource="#aspectratio" property="bibo:hasPart">
- <h3 id="h-aspectratio" resource="#h-aspectratio"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.3 </span>#aspectRatio</span></h3>
-
- <p>A <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a> supports the <code>#aspectRatio</code> feature if it recognizes and is capable of
- transforming values of the <a href="#ttp-aspectRatio"><code>ittp:aspectRatio</code></a>.</p>
-
- <p>A <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> supports the <code>#aspectRatio</code> feature if it implements presentation semantic
- support for values of the <a href="#ttp-aspectRatio"><code>ittp:aspectRatio</code></a> attribute.</p>
- </section>
-
- <section class="appendix" id="forceddisplay" typeof="bibo:Chapter" resource="#forceddisplay" property="bibo:hasPart">
- <h3 id="h-forceddisplay" resource="#h-forceddisplay"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.4 </span>#forcedDisplay</span></h3>
-
- <p>A <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a> supports the <code>#forcedDisplay</code> feature if it recognizes and is capable of
- transforming values of the <a href="#tts-forcedDisplay"><code>itts:forcedDisplay</code></a>.</p>
-
- <p>A <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> supports the <code>#forcedDisplay</code> feature if it implements presentation semantic
- support for values of the <a href="#tts-forcedDisplay"><code>itts:forcedDisplay</code></a> attribute.</p>
- </section>
-
- <section class="appendix" id="alttext" typeof="bibo:Chapter" resource="#alttext" property="bibo:hasPart">
- <h3 id="h-alttext" resource="#h-alttext"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.5 </span>#altText</span></h3>
-
- <p>A <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a> supports the <code>#altText</code> feature if it recognizes and is capable of
- transforming values of the <a href="#ttm-altText"><code>ittm:altText</code></a> element.</p>
-
- <p>A <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> supports the <code>#altText</code> feature if it implements presentation semantic support
- for values of the <a href="#ttm-altText"><code>ittm:altText</code></a> element.</p>
- </section>
-
- <section class="appendix" id="linepadding" typeof="bibo:Chapter" resource="#linepadding" property="bibo:hasPart">
- <h3 id="h-linepadding" resource="#h-linepadding"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.6 </span>#linePadding</span></h3>
-
- <p>A <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a> supports the <code>#linePadding</code> feature if it recognizes and is capable of
- transforming values of the <code>ebutts:linePadding</code> attribute specified in [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>].</p>
-
- <p>A <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> supports the <code>#linePadding</code> feature if it implements presentation semantic
- support for values of the <code>ebutts:linePadding</code> attribute specified in [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>].</p>
- </section>
-
- <section class="appendix" id="multirowalign" typeof="bibo:Chapter" resource="#multirowalign" property="bibo:hasPart">
- <h3 id="h-multirowalign" resource="#h-multirowalign"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.7 </span>#multiRowAlign</span></h3>
-
- <p>A <a href="#dfn-transformation-processor" class="internalDFN" data-link-type="dfn">transformation processor</a> supports the <code>#multiRowAlign</code> feature if it recognizes and is capable of
- transforming values of the <code>ebutts:multiRowAlign</code> attribute specified in [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>].</p>
-
- <p>A <a href="#dfn-presentation-processor" class="internalDFN" data-link-type="dfn">presentation processor</a> supports the <code>#multiRowAlign</code> feature if it implements presentation semantic
- support for values of the <code>ebutts:multiRowAlign</code> attribute specified in [<cite><a class="bibref" href="#bib-EBU-TT-D">EBU-TT-D</a></cite>].</p>
- </section>
- </section>
-
- <section class="appendix" id="xml-schemas" typeof="bibo:Chapter" resource="#xml-schemas" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-xml-schemas" resource="#h-xml-schemas"><span property="xhv:role" resource="xhv:heading"><span class="secno">G. </span>XML Schema Definitions (non-normative)</span></h2>
-
- <p>XML Schema definitions (see [<cite><a class="bibref" href="#bib-xmlschema-1">xmlschema-1</a></cite>]) for extension vocabulary defined
- by this specification are provided <a href="./xml-schemas">here</a> for convenience.</p>
-
- <p>These definitions are non-normative and are not sufficient to validate conformance of a <a href="#dfn-document-instance" class="internalDFN" data-link-type="dfn">Document Instance</a>.</p>
-
- <p>In any case where a definition specified by this appendix diverge from the prose of the specification,
- then the latter takes precedence.</p>
-
-
- </section>
-
-
- <section class="appendix" id="simple-scripts" typeof="bibo:Chapter" resource="#simple-scripts" property="bibo:hasPart">
- <!--OddPage--><h2 id="h-simple-scripts" resource="#h-simple-scripts"><span property="xhv:role" resource="xhv:heading"><span class="secno">H. </span>Simple Scripts</span></h2>
-
- <p>The following table refers to the value of the script property associated with Unicode characters.</p>
-
- <table class="simple">
- <thead>
- <tr>
- <th>Simple scripts</th>
-
- </tr>
- </thead>
-
- <tbody>
-
-
- <tr>
-
- <td>
- Latin
- </td>
- </tr>
-
- <tr>
-
- <td>
- Hebrew
- </td>
- </tr>
-
- <tr>
-
- <td>
- Cyrillic
- </td>
- </tr>
-
- <tr>
-
- <td>
- Greek
- </td>
- </tr>
- </tbody>
- </table>
-
-
- </section>
-
-
-<section id="references" class="appendix" typeof="bibo:Chapter" resource="#references" property="bibo:hasPart"><!--OddPage--><h2 id="h-references" resource="#h-references"><span property="xhv:role" resource="xhv:heading"><span class="secno">I. </span>References</span></h2><section id="normative-references" typeof="bibo:Chapter" resource="#normative-references" property="bibo:hasPart"><h3 id="h-normative-references" resource="#h-normative-references"><span property="xhv:role" resource="xhv:heading"><span class="secno">I.1 </span>Normative references</span></h3><dl class="bibliography" resource=""><dt id="bib-CLDR">[CLDR]</dt><dd>Unicode Consortium. <a href="http://cldr.unicode.org" property="dc:requires">The Common Locale Data Repository Project</a>
-</dd><dt id="bib-EBU-TT-D">[EBU-TT-D]</dt><dd>European Broadcasting Union (EBU). <a href="https://tech.ebu.ch/docs/tech/tech3380.pdf" property="dc:requires">Tech 3380, EBU-TT-D Subtitling Distribution Format Version 1.0</a>
-</dd><dt id="bib-PNG">[PNG]</dt><dd>Tom Lane. <a href="http://www.w3.org/TR/PNG" property="dc:requires"><cite>Portable Network Graphics (PNG) Specification (Second Edition)</cite></a>. 10 November 2003. W3C Recommendation. URL: <a href="http://www.w3.org/TR/PNG" property="dc:requires">http://www.w3.org/TR/PNG</a>
-</dd><dt id="bib-RFC2119">[RFC2119]</dt><dd>S. Bradner. <a href="https://tools.ietf.org/html/rfc2119" property="dc:requires"><cite>Key words for use in RFCs to Indicate Requirement Levels</cite></a>. March 1997. Best Current Practice. URL: <a href="https://tools.ietf.org/html/rfc2119" property="dc:requires">https://tools.ietf.org/html/rfc2119</a>
-</dd><dt id="bib-ST2052-1">[ST2052-1]</dt><dd>SMPTE ST 2052-1, Timed Text Format (SMPTE-TT) URL: <a href="https://www.smpte.org/standards " property="dc:requires">https://www.smpte.org/standards</a>
-</dd><dt id="bib-TTML1">[TTML1]</dt><dd>Glenn Adams. <a href="http://www.w3.org/TR/ttml1/" property="dc:requires"><cite>Timed Text Markup Language 1 (TTML1) (Second Edition)</cite></a>. 24 September 2013. W3C Recommendation. URL: <a href="http://www.w3.org/TR/ttml1/" property="dc:requires">http://www.w3.org/TR/ttml1/</a>
-</dd><dt id="bib-UNICODE">[UNICODE]</dt><dd><a href="http://www.unicode.org/versions/latest/" property="dc:requires"><cite>The Unicode Standard</cite></a>. URL: <a href="http://www.unicode.org/versions/latest/" property="dc:requires">http://www.unicode.org/versions/latest/</a>
-</dd><dt id="bib-WCAG20">[WCAG20]</dt><dd>Ben Caldwell; Michael Cooper; Loretta Guarino Reid; Gregg Vanderheiden et al. <a href="http://www.w3.org/TR/WCAG20/" property="dc:requires"><cite>Web Content Accessibility Guidelines (WCAG) 2.0</cite></a>. 11 December 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/WCAG20/" property="dc:requires">http://www.w3.org/TR/WCAG20/</a>
-</dd><dt id="bib-xml-names">[xml-names]</dt><dd>Tim Bray; Dave Hollander; Andrew Layman; Richard Tobin; Henry Thompson et al. <a href="http://www.w3.org/TR/xml-names" property="dc:requires"><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" property="dc:requires">http://www.w3.org/TR/xml-names</a>
-</dd></dl></section><section id="informative-references" typeof="bibo:Chapter" resource="#informative-references" property="bibo:hasPart"><h3 id="h-informative-references" resource="#h-informative-references"><span property="xhv:role" resource="xhv:heading"><span class="secno">I.2 </span>Informative references</span></h3><dl class="bibliography" resource=""><dt id="bib-CEA-608">[CEA-608]</dt><dd><a href="http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/Line-21-Data-Service.aspx" property="dc:references">Line-21 Data Services</a>, ANSI/CEA Standard.
-</dd><dt id="bib-CEA-708">[CEA-708]</dt><dd><a href="http://www.ce.org/Standards/Standard-Listings/R4-3-Television-Data-Systems-Subcommittee/CEA-708-D.aspx" property="dc:references">Digital Television (DTV) Closed Captioning</a>, ANSI/CEA Standard.
-</dd><dt id="bib-HTML5">[HTML5]</dt><dd>Ian Hickson; Robin Berjon; Steve Faulkner; Travis Leithead; Erika Doyle Navara; Edward O'Connor; Silvia Pfeiffer. <a href="http://www.w3.org/TR/html5/" property="dc:references"><cite>HTML5</cite></a>. 28 October 2014. W3C Recommendation. URL: <a href="http://www.w3.org/TR/html5/" property="dc:references">http://www.w3.org/TR/html5/</a>
-</dd><dt id="bib-SUBM">[SUBM]</dt><dd>World Wide Web Consortium (W3C). <a href="http://www.w3.org/Submission/2013/SUBM-ttml-ww-profiles-20130607/" property="dc:references">TTML Text and Image Profiles for Internet Media Subtitles and Captions</a> (Member Submission, 07 June 2013)
-</dd><dt id="bib-namespaceState">[namespaceState]</dt><dd>Norman Walsh. <a href="http://www.w3.org/TR/namespaceState/" property="dc:references"><cite>The Disposition of Names in an XML Namespace</cite></a>. 29 March 2006. W3C Working Draft. URL: <a href="http://www.w3.org/TR/namespaceState/" property="dc:references">http://www.w3.org/TR/namespaceState/</a>
-</dd><dt id="bib-ttml10-sdp-us">[ttml10-sdp-us]</dt><dd>Glenn Adams; Monica Martin; Sean Hayes. <a href="http://www.w3.org/TR/ttml10-sdp-us/" property="dc:references"><cite>TTML Simple Delivery Profile for Closed Captions (US)</cite></a>. 5 February 2013. W3C Note. URL: <a href="http://www.w3.org/TR/ttml10-sdp-us/" property="dc:references">http://www.w3.org/TR/ttml10-sdp-us/</a>
-</dd><dt id="bib-xmlschema-1">[xmlschema-1]</dt><dd>Henry Thompson; David Beech; Murray Maloney; Noah Mendelsohn et al. <a href="http://www.w3.org/TR/xmlschema-1/" property="dc:references"><cite>XML Schema Part 1: Structures Second Edition</cite></a>. 28 October 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/xmlschema-1/" property="dc:references">http://www.w3.org/TR/xmlschema-1/</a>
-</dd></dl></section></section></body></html>
\ No newline at end of file
+<!DOCTYPE html>
+<html>
+ <head>
+ <meta charset="utf-8" />
+ <title>Redirect to Editor's Draft of IMSC1</title>
+ <meta http-equiv="REFRESH" content="5; url=https://rawgit.com/w3c/imsc1/master/spec/ttml-ww-profiles.html" />
+ </head>
+ <body>
+ <p>The IMSC1 repository has been permanently moved to
+ <a href="https://github.com/w3c/imsc1">https://github.com/w3c/imsc1</a>.</p>
+
+ <p>The latest Editor's Draft can be viewed at
+ <a href="https://rawgit.com/w3c/imsc1/master/spec/ttml-ww-profiles.html">https://rawgit.com/w3c/imsc1/master/spec/ttml-ww-profiles.html</a>,
+ where you will be redirected shortly.</p>
+ </body>
+</html>
--- a/ttml-ww-profiles/ttml-ww-profiles.source.html Sat Oct 31 12:02:25 2015 -0700
+++ b/ttml-ww-profiles/ttml-ww-profiles.source.html Sat Oct 31 22:26:01 2015 -0700
@@ -1,3177 +1,16 @@
<!DOCTYPE html>
-
<html>
-<head>
- <meta charset='utf-8'>
-
- <title>TTML Profiles for Internet Media Subtitles and Captions 1.0 (IMSC1)</title>
- <script src='https://www.w3.org/Tools/respec/respec-w3c-common' async="" class='remove'>
-</script>
- <script class='remove'>
-var respecConfig = {
- specStatus: "ED"
- , crEnd: "2015-01-16"
- , implementationReportURI: "https://www.w3.org/wiki/TimedText/IMSC1_Implementation_Report"
- , processVersion: "2014"
- , previousMaturity: "CR"
- /*, publishDate: "2014-12-09"*/
- , sotdAfterWGinfo: "true"
- , previousPublishDate: "2014-12-09"
- , shortName: "ttml-imsc1"
- , editors: [{ name: "Pierre Lemieux", mailto: "pal@sandflow.com" }]
- , wg: "Timed Text Working Group"
- , wgURI: "http://www.w3.org/AudioVideo/TT/"
- , wgPublicList: "public-tt"
- , wgPatentURI: "http://www.w3.org/2004/01/pp-impl/34314/status"
- , subjectPrefix: "[imsc]"
- , edDraftURI: "https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml-ww-profiles/ttml-ww-profiles.html"
- , localBiblio: {
- "SUBM": "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)",
- "CEA-608": "<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.",
- "CEA-708": "<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.",
- "ST2052-1": "SMPTE ST 2052-1, Timed Text Format (SMPTE-TT) URL: <a href='https://www.smpte.org/standards '>https://www.smpte.org/standards</a>",
- "EBU-TT-D": "European Broadcasting Union (EBU). <a href='https://tech.ebu.ch/docs/tech/tech3380.pdf'>Tech 3380, EBU-TT-D Subtitling Distribution Format Version 1.0</a>",
-
- "CLDR": "Unicode Consortium. <a href='http://cldr.unicode.org'>The Common Locale Data Repository Project</a>",
-
- }
- };
- </script>
- <style type="text/css">
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- .note {font-size:small}
- .equation {text-indent: 10%;}
- .example {font-size: small}
- </style>
-</head>
-
-<body>
- <section id='abstract'>
- <p>This document specifies two profiles of [[!TTML1]]: 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
- [[ttml10-sdp-us]].</p>
-
- <p>The document defines extensions to [[!TTML1]], as well as incorporates extensions specified in [[!ST2052-1]] and
- [[!EBU-TT-D]].</p>
-
- <p>Both profiles are based on [[SUBM]].</p>
- </section>
-
- <section id='sotd'>
- <p>
- For this specification to exit the CR stage, at least 2 independent implementations of every feature
- defined in this specification but not already present in [[!TTML1]] need to be documented in the implementation
- report. The implementation report is based on implementer-provided test results for the <a href="https://dvcs.w3.org/hg/ttml/file/tip/ttml-ww-profiles/testsuite">test suite</a> (tests and sample
- content) maintained by the Working Group. The Working Group does not require that implementations are publicly available
- but encourages them to be so.
- </p>
-
- <p>The Working Group expects the test suite and the implementation report to evolve significantly before the specification advances to Proposed Recommendation.</p>
- <p>The Working Group has not identified features "at risk" for this specification.</p>
- </section>
-
- <section id='scope'>
- <h2>Scope</h2>
-
- <p>This document specifies two profiles of [[!TTML1]]: 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 text-only profile is a strict superset of [[ttml10-sdp-us]].</p>
-
- <p>The document defines extensions to [[!TTML1]], as well as incorporates extensions specified in [[!ST2052-1]] and
- [[!EBU-TT-D]].</p>
- </section>
-
- <section id='conventions'>
- <h2>Documentation Conventions</h2>
-
- <p>This specification uses the same conventions as [[!TTML1]] for the specification of parameter attributes, styling attributes and metadata elements. In particular, Section 2.3 of [[!TTML1]] specifies conventions used in the XML representation of elements.</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>
- </section>
-
- <section id='terms'>
- <h2>Terms and Definitions</h2>
-
- <p><dfn>Default Region</dfn>. See Section 9.3.1 at [[!TTML1]].</p>
-
- <p><dfn>Document Instance</dfn>. See Section 2.2 at [[!TTML1]].</p>
-
- <p><dfn>Intermediate synchronic document</dfn>. See Section 9.3.2 at [[!TTML1]].</p>
-
- <p><dfn>Processor</dfn>. Either a <a>Presentation processor</a> or a <a>Transformation processor</a>.</p>
-
- <p><dfn>Presentation processor</dfn>. See Section 2.2 at [[!TTML1]].</p>
-
- <p><dfn>Transformation processor</dfn>. See Section 2.2 at [[!TTML1]].</p>
-
- <p><dfn>Related Media Object</dfn>. See Section 2.2 at [[!TTML1]].</p>
-
- <p><dfn>Related Video Object</dfn>. A <a>Related Media Object</a> that consists of a sequence of image frames, each a rectangular array of pixels.</p>
-
- <p><dfn>text alternative</dfn>. As defined in [[!WCAG20]].</p>
-
- </section>
-
- <section id="conformance">
-
- <p>A <a>Document Instance</a> that conforms to a profile defined herein:</p>
-
-
-
- <ul>
- <li>SHALL satisfy all normative provisions specified by the profile;</li>
- <li>MAY use any vocabulary, syntax or attribute values whose interpretation will be successfully processed by a processor that supports "permitted" features;</li>
- <li>SHALL NOT use any vocabulary, syntax or attribute values that would require the processor to implement any "prohibited" features to successfully process the document.</li>
- </ul>
-
-
-
- <p>A <a>presentation processor</a> that conforms to a profile defined in this specification:</p>
-
- <ul>
- <li>SHALL satisfy the Generic Processor Conformance requirements at Section 3.2.1 of [[!TTML1]];</li>
-
- <li>SHALL satisfy all normative provisions specified by the profile; and</li>
-
- <li>SHALL implement presentation semantic support for all features designated as "permitted" by the profile, subject to
- any additional constraints on features as specified by the profile.</li>
- </ul>
-
- <p>A <a>transformation processor</a> that conforms to a profile defined in this specification:</p>
-
- <ul>
- <li>SHALL satisfy the Generic Processor Conformance requirements at Section 3.2.1 of [[!TTML1]];</li>
-
- <li>SHALL satisfy all normative provisions specified by the profile; and</li>
-
- <li>SHALL implement transformation semantic support for all features designated as "permitted" by the profile, subject to
- any additional constraints on features as specified by the profile.</li>
- </ul>
-
- <p class='note'>The use of the term <a>presentation processor</a> (<a>transformation processor</a>) within this specification
- does not imply conformance to the DFXP Presentation Profile (DFXP Transformation Profile) specified in [[!TTML1]]. In other
- words, it is not considered an error for a <a>presentation processor</a> (<a>transformation processor</a>) to conform to a
- profile defined in this specification without also conforming to the DFXP Presentation Profile (DFXP Transformation
- Profile).</p>
-
- <p class='note'>This specification does not specify <a>presentation processor</a> or <a>transformation processor</a> behavior when processing or transforming a non-conformant <a>Document Instance</a>.</p>
- </section>
-
- <section id='profiles'>
- <h2>Profiles</h2>
-
- <section>
- <h3>General</h3>
-
- <p>A <a>Document Instance</a> SHALL NOT conform to the <a>Text Profile</a> and <a>Image Profile</a> simultaneously.</p>
-
- <p>In applications that require subtitle/caption content in image form to be simultaneously available in text form, two
- distinct <a data-lt="Document Instance">Document Instances</a>, one conforming to the <a>Text Profile</a> and the other conforming to the <a>Image Profile</a>,
- SHOULD be offered. In addition, the <a>Text Profile</a> <a>Document Instance</a> SHOULD be associated with the <a>Image Profile</a>
- <a>Document Instance</a> such that, when image content is encountered, assistive technologies have access to its corresponding text
- form. The method by which this association is made is left to each application.</p>
-
- <p class='note'>The <code>ittm:altText</code> element specified <a href='#ttm-altText'></a> also allows text equivalent
- string to be associated with an image, e.g. to support indexation of the content and also facilitate quality checking of the
- document during authoring.</p>
-
- <p>Annex <a href='#wcag-applications'></a> specifically discusses this specification in the context of the [[WCAG20]]
- guidelines.</p>
- </section>
-
- <section>
- <h3>Text Profile</h3>
-
- <p>The <dfn>Text Profile</dfn> consists of Sections <a href="#common-constraints"></a> and <a href=
- "#text-profile-constraints"></a>.</p>
- </section>
-
- <section>
- <h3>Image Profile</h3>
-
- <p>The <dfn>Image Profile</dfn> consists of Sections <a href="#common-constraints"></a> and <a href=
- "#image-profile-constraints"></a>.</p>
- </section>
- </section>
-
- <section id='common-constraints'>
- <h2>Common Constraints</h2>
-
- <section>
- <h3>Document Encoding</h3>
-
- <p>A <a>Document Instance</a> SHALL use UTF-8 character encoding as specified in [[!UNICODE]].</p>
- </section>
-
- <section>
- <h3>Foreign Element and Attributes</h3>
-
- <p>A <a>Document Instance</a> MAY contain elements and attributes that are neither specifically permitted nor forbidden by a
- profile.</p>
- </section>
-
- <section>
- <h3>Namespaces</h3>
-
- <p>The following namespaces (see [[!xml-names]]) are used in this specification:</p>
-
- <table class='simple'>
- <thead>
- <tr>
- <th>Name</th>
-
- <th>Prefix</th>
-
- <th>Value</th>
-
- <th>Defining Specification</th>
- </tr>
- </thead>
-
- <tbody>
- <tr>
- <td>XML</td>
-
- <td>xml</td>
-
- <td>http://www.w3.org/XML/1998/namespace</td>
-
- <td>[[!xml-names]]</td>
- </tr>
-
- <tr>
- <td>TT Parameter</td>
-
- <td>ttp</td>
-
- <td>http://www.w3.org/ns/ttml#parameter</td>
-
- <td>[[!TTML1]]</td>
- </tr>
-
- <tr>
- <td>TT Styling</td>
-
- <td>tts</td>
-
- <td>http://www.w3.org/ns/ttml#styling</td>
-
- <td>[[!TTML1]]</td>
- </tr>
-
- <tr>
- <td>TT Feature</td>
-
- <td><em>none</em></td>
-
- <td>http://www.w3.org/ns/ttml/feature/</td>
-
- <td>[[!TTML1]]</td>
- </tr>
-
- <tr>
- <td>SMPTE-TT Extension</td>
-
- <td>smpte</td>
-
- <td>http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt</td>
-
- <td>[[!ST2052-1]]</td>
- </tr>
-
- <tr>
- <td>EBU-TT Styling</td>
-
- <td>ebutts</td>
-
- <td>urn:ebu:tt:style</td>
-
- <td>[[!EBU-TT-D]]</td>
- </tr>
-
- <tr>
- <td>EBU-TT Metadata</td>
-
- <td>ebuttm</td>
-
- <td>urn:ebu:tt:metadata</td>
-
- <td>[[!EBU-TT-D]]</td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Styling</td>
-
- <td>itts</td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1#styling</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Parameter</td>
-
- <td>ittp</td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1#parameter</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Metadata</td>
-
- <td>ittm</td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1#metadata</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Extension</td>
-
- <td><em>none</em></td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1/extension/</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Text Profile Designator</td>
-
- <td><em>none</em></td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1/text</td>
-
- <td><em>This specification</em></td>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Image Profile Designator</td>
-
- <td><em>none</em></td>
-
- <td>http://www.w3.org/ns/ttml/profile/imsc1/image</td>
-
- <td><em>This specification</em></td>
- </tr>
- </tbody>
- </table>
-
- <p>The namespace prefix values defined above are for convenience and <a data-lt='Document Instance'>Document Instances</a> MAY use any prefix value that
- conforms to [[!xml-names]].</p>
-
- <p>The namespaces defined by this specification are mutable [[namespaceState]]; all undefined names in these namespaces are reserved for future standardization by the W3C.</p>
- </section>
-
- <section>
- <h3>Overflow</h3>
-
- <p>A <a>Document Instance</a> SHOULD be authored assuming strict clipping of content that falls out of region areas, regardless of
- the computed value of <code>tts:overflow</code> for the region.</p>
-
- <p class="note">As specified in [[!TTML1]], <code>tts:overflow</code> has no effect on the extent of the region, and hence
- the total normalized drawing area S(En) at <a href='#paint-regions'></a>.</p>
- </section>
-
- <section>
- <h3>Related Video Object</h3>
-
- <p>A <a>Document Instance</a> MAY be associated with a <a>Related Video Object</a>.</p>
-
- <p class="note">While this specification contains specific provisions when a <a>Document Instance</a> is associated with a <a>Related Video Object</a>, it does not prevent the use of a <a>Document Instance</a> with other kinds of <a>Related Media Object</a>, e.g. an audio object.</p>
- </section>
-
- <section>
- <h3>Synchronization</h3>
-
- <p>Each <a>intermediate synchronic document</a> of the <a>Document Instance</a> is intended to be displayed on a specific frame and
- removed on a specific frame of the <a>Related Video Object</a>.</p>
-
- <p>When mapping a media time expression M to a frame F of a <a>Related Video Object</a>, e.g. for the purpose of rendering a
- <a>Document Instance</a> onto the <a>Related Video Object</a>, the <a>presentation processor</a> SHALL map M to the frame F with the
- presentation time that is the closest to, but not less, than M.</p>
-
- <aside class="example">
- 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>
-
- <p class="note">In typical scenario, the same video program (the <a>Related Video Object</a>) will be used for <a>Document Instance</a>
- authoring, delivery and user playback. The mapping from media time expression to <a>Related Video Object</a> above allows the author
- to precisely associate subtitle video content with video frames, e.g. around scene transitions. In circumstances where the
- video program is downsampled during delivery, the application can specify that, at playback, the relative video object be
- considered the delivered video program upsampled to is original rate, thereby allowing subtitle content to be rendered at the
- same temporal locations it was authored.</p>
-
- </section>
-
- <section>
- <h3>Extensions</h3>
-
- <section id='ttp-aspectRatio'>
- <h4>ittp:aspectRatio</h4>
-
- <p>The <code>ittp:aspectRatio</code> attributes allows authorial control of the mapping of the root container of a <a>Document Instance</a> to the <a>Related Video Object</a> frame.</p>
-
- <p>If present, the <code>ittp:aspectRatio</code> attribute SHALL conform to the following syntax:</p>
-
- <table class="syntax">
- <tbody>
- <tr>
- <td>
- <div class="exampleInner">
- <pre>
-ittp:aspectRatio
- : numerator denominator // with int(numerator) != 0 and int(denominator) != 0
- // where int(s) parses string s as a decimal integer.
-
-numerator | denominator
- : <digit>+
-</pre>
- </div>
- </td>
- </tr>
- </tbody>
- </table>
-
- <p>The root container of a <a>Document Instance</a> SHALL be mapped to the <a>Related Video Object</a> frame according to the
- following:</p>
-
- <ol>
- <li>
- <p>If <code>ittp:aspectRatio</code> is present, the root container SHALL be mapped to a rectangular area within the
- <a>Related Video Object</a> such that:</p>
-
- <ol style="list-style-type: lower-roman;">
- <li>the ratio of the width to the height of the rectangular area is equal to <code>ittp:aspectRatio</code>,</li>
-
- <li>the center of the rectangular area is collocated with the center of the <a>Related Video Object</a> frame,</li>
-
- <li>the rectangular area (including its boundary) is entirely within the <a>Related Video Object</a> frame (including its
- boundary), and</li>
-
- <li>the rectangular area has a height or width equal to that of the <a>Related Video Object</a> frame.</li>
- </ol>
- </li>
-
- <li>
- <p>Otherwise, the root container of a <a>Document Instance</a> SHALL be mapped to the <a>Related Video Object</a> frame in its
- entirety.</p>
- </li>
- </ol>
-
- <p>An <code>ittp:aspectRatio</code> attribute is considered to be significant only when specified on the <code>tt</code>
- element.</p>
-
-<aside class='example'>
-<p>Region <code>"A"</code> in the following document would be positioned 20% from the left edge of a <a>Related Video Object</a> with an aspect ratio of 16:9,
- or 10% from the left edge of a <a>Related Video Object</a> with an aspect ratio of 4:3.</p>
-<pre>
-<tt
- xmlns="http://www.w3.org/ns/ttml"
- xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
- xmlns:tts="http://www.w3.org/ns/ttml#styling"
- xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
- xmlns:ittp="http://www.w3.org/ns/ttml/profile/imsc1#parameter"
- ittp:aspectRatio="4 3"
- tts:extent="400px 300px"
- >
- ...
- <region id="A" tts:origin="40px 10px" tts:extent="320px 10px">
- ...
-</tt>
-</pre>
-<p>In other words, <code>tts:extent</code>, when present on the <code>tt</code> element, determines the size of <code>"px"</code> units relative to the root container. <code>ttp:aspectRatio</code> is independently used to map the root container to the <a>Related Video Object</a>.
-</aside>
-
-<p class='note'>
-The <code>ittp:aspectRatio</code> parameter effectively defines the intended display aspect ratio (DAR) of the root container, while
- the <code>tts:extent</code> style property on the root element effectively defines the intended storage aspect ratio (SAR) of the root container.
-</p>
- </section>
- <section id='ttp-progressivelyDecodable'>
- <h4>ittp:progressivelyDecodable</h4>
-
- <p>A <a>progressively decodable Document Instance</a> is structured to facilitate presentation before the document is
- received in its entirety, and can be identified using <code>ittp:progressivelyDecodable</code> attribute.</p>
-
- <p>A <dfn>progressively decodable Document Instance</dfn> is a <a>Document Instance</a> that conforms to the following:</p>
-
- <ol>
- <li>no attribute or element of the TTML timing vocabulary is present within the <code>head</code> element;</li>
-
- <li>given two <a data-lt="intermediate synchronic document">intermediate synchronic documents</a> <em>A</em> and <em>B</em>
- of the <a>Document Instance</a>, with start times <em>TA</em> and <em>TB</em>, respectively, <em>TA</em> is not greater than
- <em>TB</em> if <em>A</em> includes a <code>p</code> element that lexically precedes any <code>p</code>
- element that <em>B</em> includes;
- </li>
-
- <li>no attribute of the TTML timing vocabulary is present on a descendant element of <code>p</code>; and</li>
-
- <li>no element <em>E1</em> explicitly references another element <em>E2</em> where the opening tag of <em>E2</em> is lexically subsequent to the opening tag of <em>E1</em>.</li>
- </ol>
-
- <p>If present, the <code>ittp:progressivelyDecodable</code> attribute SHALL conform to the following syntax:</p>
-
- <table class="syntax">
- <tbody>
- <tr>
- <td>
- <div class="exampleInner">
- <pre>
-ittp:progressivelyDecodable
- : "true"
- | "false"
-</pre>
- </div>
- </td>
- </tr>
- </tbody>
- </table>
-
- <p>An <code>ittp:progressivelyDecodable</code> attribute is considered to be significant only when specified on the
- <code>tt</code> element.</p>
-
- <p>If not specified, the value of <code>ittp:progressivelyDecodable</code> SHALL be considered to be equal to "false".</p>
-
- <p>A <a>Document Instance</a> for which the computed value of <code>ittp:progressivelyDecodable</code> is "true" SHALL be a
- <a>progressively decodable Document Instance</a>.</p>
-
- <p>A <a>Document Instance</a> for which the computed value of <code>ittp:progressivelyDecodable</code> is "false" is neither
- asserted to be a <a>progressively decodable Document Instance</a> nor asserted not to be a progressively decodable <a>Document Instance</a>.</p>
-
- <pre class='example'>
-<tt
- xmlns="http://www.w3.org/ns/ttml"
- xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
- xmlns:tts="http://www.w3.org/ns/ttml#styling"
- xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
- xmlns:ittp="http://www.w3.org/ns/ttml/profile/imsc1#parameter"
- ittp:progressivelyDecodable="true"
- >
- ...
-</tt>
-</pre>
-
- <div class='note'>
- <p>[[!TTML1]] specifies explicitly referencing of elements identified using <code>xml:id</code> in the following
- circumstances:</p>
-
- <ul>
- <li>an element in <code>body</code> referencing <code>region</code> elements. In this case, Requirement 4 above is
- always satisfied.</li>
-
- <li>an element in <code>body</code> referencing <code>style</code> elements. In this case, Requirement 4 above is
- always satisfied.</li>
-
- <li>a <code>region</code> element referencing <code>style</code> elements. In this case, Requirement 4 above is always
- satisfied.</li>
-
- <li>a <code>style</code> element referencing other <code>style</code> elements. In this case, Requirement 4 provides an
- optimization of <code>style</code> element ordering within the <code>head</code> element.</li>
-
- <li>a <code>ttm:actor</code> element referencing a <code>ttm:agent</code> element. In this case, Requirement 4 provides
- optimization of metadata elements ordering within the document.</li>
-
- <li>a content element referencing <code>ttm:agent</code> elements using the <code>ttm:agent</code> attribute. In this
- case, Requirement 4 provides optimization of metadata elements ordering within the document.</li>
- </ul>
- </div>
- </section>
-
- <section id='tts-forcedDisplay'>
- <h4>itts:forcedDisplay</h4>
-
- <p><code>itts:forcedDisplay</code> can be used to hide content whose computed value of <code>tts:visibility</code> is <code>"visible"</code> when the processor has been configured to do so via the application parameter <code>displayForcedOnlyMode</code>.</p>
-
- <p>If and only if the value of <code>displayForcedOnlyMode</code> is "true", a content element with a <code>itts:forcedDisplay</code>
- computed value of "false" SHALL NOT produce any visible rendering, but still affect layout, regardless of the computed
- value of <code>tts:visibility</code>.</p>
-
- <p>The <code>itts:forcedDisplay</code> attribute shall conform to the following:</p>
-
- <table class="simple">
- <colgroup>
- <col style="width:25%" span="1">
- <col span="1">
- </colgroup>
-
- <tbody>
- <tr>
- <td><em>Values:</em></td>
-
- <td><code>false | true</code></td>
- </tr>
-
- <tr>
- <td><em>Initial:</em></td>
-
- <td><code>false</code></td>
- </tr>
-
- <tr>
- <td><em>Applies to:</em></td>
-
- <td><code>body</code>, <code>div</code>, <code>p</code>, <code>region</code>, <code>span</code></td>
- </tr>
-
- <tr>
- <td><em>Inherited:</em></td>
-
- <td>yes</td>
- </tr>
-
- <tr>
- <td><em>Percentages:</em></td>
-
- <td>N/A</td>
- </tr>
-
- <tr>
- <td><em>Animatable:</em></td>
-
- <td>discrete</td>
- </tr>
- </tbody>
- </table>
-
- <p>Annex <a href='#forced-content'></a> illustrates the use of <code>itts:forcedDisplay</code> in an application in which a
- single document contains both hard of hearing captions and translated foreign language subtitles, using
- <code>itts:forcedDisplay</code> to display translation subtitles always, independently of whether the hard of hearing
- captions are displayed or hidden.</p>
-
- <p>The <a>presentation processor</a> SHALL accept an optional boolean parameter called <code>displayForcedOnlyMode</code>,
- whose value MAY be set by a context external to the <a>presentation processor</a>. If not set, the value of
- <code>displayForcedOnlyMode</code> SHALL be assumed to be equal to "false".</p>
-
- <p>The algorithm for setting the <code>displayForcedOnlyMode</code> parameter based on the circumstances under which the
- <a>Document Instance</a> is presented is left to the application.</p>
-
- <pre class='example'>
-...
-<head>
- ...
- <region xml:id="r1" tts:origin="10% 2%" tts:extent="80% 10%" tts:color="white" itts:forcedDisplay="true" tts:backgroundColor="black"/>
- <region xml:id="r2" tts:origin="10% 80%" tts:extent="80% 88%" tts:color="white" tts:backgroundColor="black"/>
- ...
-</head>
-...
-<div>
- <p region="r1" begin="1s" end="6s">Lycée</p>
-
- <!-- the following will not appear if displayForcedOnlyMode='true' -->
- <p region="r2" begin="4s" end="6s">Nous étions inscrits au même lycée.</p>
-</div>
-...
-</pre>
-
-
- <p class='note'>As specified in [[!TTML1]], the background of a region can be visible even if the computed value of <code>tts:visibility</code> equals
- "hidden" for all active content within. The background of a region for which <code>itts:forcedDisplay</code> equals "true" can therefore remain visible even if <code>itts:forcedDisplay</code> equals "false" for all active
- content elements within the region and <code>displayForcedOnlyMode</code> equals "true". Authors can avoid this situation, for instance, by ensuring that content
- elements and the regions that they are flowed into always have the same value of <code>itts:forcedDisplay</code>.</p>
-
- <p class='note'>Although <code>itts:forcedDisplay</code>, like all the TTML style attributes, has no defined semantics on a
- <code>br</code> content element, <code>itts:forcedDisplay</code> will apply to a <code>br</code> content element if it is
- either defined on an ancestor content element of the <code>br</code> content element or it is applied to a region element
- corresponding to a region that the <code>br</code> content element is being flowed into.</p>
-
- <p class='note'>It is expected that the functionality of <code>itts:forcedDisplay</code> will be mapped to a conditional
- style construct in a future revision of this specification.</p>
- </section>
-
- <section id='ttm-altText'>
- <h4>ittm:altText</h4>
-
- <p><code>ittm:altText</code> allows an author to provide a text string equivalent for an element, typically an image. This
- text equivalent MAY be used to support indexing of the content and also facilitate quality checking of the document during
- authoring.</p>
-
- <p>The <code>ittm:altText</code> element SHALL conform to the following syntax:</p>
-
- <table class="syntax">
- <tbody>
- <tr>
- <td>
- <div class="exampleInner">
- <pre>
-<ittm:altText
- xml:id = ID
- xml:lang = string
- xml:space = (default|preserve)
- {any attribute not in the default namespace, any TT namespace or any IMSC 1.0 namespace}>
- Content: #PCDATA
-</ittm:altText>
-</pre>
- </div>
- </td>
- </tr>
- </tbody>
- </table>
-
- <p>The <code>ittm:altText</code> element SHALL be a child of the <code>metadata</code> element.</p>
-
- <p><a href="#image-profile-constraints"></a> specifies the use of the <code>ittm:altText</code> element with images.</p>
-
-<pre class='example'>
-...
-<div region="r1" begin="1s" end="6s" smpte:backgroundImage="1.png">
- <metadata>
- <ittm:altText>Nous étions inscrits au même lycée.</ttm:title>
- </metadata>
-</div>
-...
-</pre>
-
- <p class='note'>In contrast to the common use of <code>alt</code> attributes in [[HTML5]], the <code>ittm:altText</code>
- attribute content is not intended to be displayed in place of the element if the element is not loaded. The
- <code>ittm:altText</code> attribute content can however be read and used by assistive technologies.</p>
- </section>
-
-
-
- </section>
-
- <section>
- <h3>Region</h3>
-
- <section>
- <h4>Presented Region</h4>
-
- <p>A <dfn>presented region</dfn> is a temporally active region that satisfies the following conditions:</p>
-
- <ol>
- <li>the computed value of <code>tts:opacity</code> is not equal to "0.0"; and</li>
-
- <li>the computed value of <code>tts:display</code> is not "none"; and</li>
-
- <li>the computed value of <code>tts:visibility</code> is not "hidden"; and</li>
-
- <li>either (a) content is selected into the region or (b) the computed value of <code>tts:showBackground</code> is equal
- to "always" and the computed value of <code>tts:backgroundColor</code> has non-transparent alpha.</li>
- </ol>
- </section>
-
- <section>
- <h4>Dimensions and Position</h4>
-
- <p>All regions SHALL NOT extend beyond 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 <a data-lt="presented region">presented regions</a> in a given <a>intermediate synchronic document</a> SHALL
- overlap, i.e. the intersection of the sets of coordinates within each region (including its boundary) is empty.</p>
- </section>
-
- <section>
- <h4>Maximum number</h4>
-
- <p>The number of <a data-lt="presented region">presented regions</a> in a given <a>intermediate synchronic document</a> SHALL
- NOT be greater than 4.</p>
- </section>
- </section>
-
- <section>
- <h3>Hypothetical Render Model</h3>
-
- <p>It SHALL be possible to apply the Hypothetical Render Model specified in Section <a href=
- "#hypothetical-render-model"></a> to any sequence of consecutive <a data-lt="intermediate synchronic document">intermediate synchronic documents</a> without error as defined in Section <a href=
- "#hypothetical-render-model-general"></a>.</p>
- </section>
-
- <section id='common-features'>
- <h3>Features</h3>
-
- <p>See <a href="#conformance"></a> for a definition of "permitted" and "prohibited".</p>
-
- <table class='simple'>
- <tbody>
- <tr>
- <th style="text-align:center">Feature</th>
-
- <th style="text-align:center">Disposition</th>
-
- <th style="text-align:center">Additional provision</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the TT Feature namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#animation</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#cellResolution</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#clockMode</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#content</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#core</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#display-block</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#display-inline</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#display-region</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#display</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#dropMode</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#extent-region</code></td>
-
- <td>permitted</td>
- <td>The <code>tts:extent</code> attribute SHALL be present on all <code>region</code> elements.</td>
- </tr>
-
- <tr>
- <td><code>#extent-root</code></td>
-
- <td>permitted</td>
- <td>If the <a>Document Instance</a> includes any length value that uses the <code>px</code> expression,
- <code>tts:extent</code> SHALL be present on the <code>tt</code> element.</td>
- </tr>
-
- <tr>
- <td><code>#extent</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#frameRate</code></td>
-
- <td>permitted</td>
- <td>If the <a>Document Instance</a> includes any clock time expression that uses the <code>frames</code> term or any offset
-time expression that uses the <code>f</code> metric, the <code>ttp:frameRate</code> attribute SHALL
-be present on the <code>tt</code> element.</td>
- </tr>
-
- <tr>
- <td><code>#frameRateMultiplier</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#layout</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-cell</code></td>
-
- <td>permitted</td>
- <td>'c' units SHALL NOT be present outside of the value of <code>ebutts:linePadding</code>.</td>
- </tr>
-
- <tr>
- <td><code>#length-integer</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-negative</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-percentage</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-pixel</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length-positive</code></td>
-
- <td>permitted</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#length-real</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#length</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#markerMode</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#metadata</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#opacity</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#origin</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#overflow</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#pixelAspectRatio</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#presentation</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#profile</code></td>
-
- <td>permitted</td>
-
- <td>
- <p>
-
- The <code>ttp:profile</code> attribute SHOULD be present on the <code>tt</code> element and equal to the designator of the IMSC1 profile
- to which the document conforms; unless the document also conforms to [[!EBU-TT-D]], in which case the <code>ttp:profile</code> attribute
- SHOULD NOT be present on the <code>tt</code> element, and instead the designator of the IMSC1 profile to which the document conforms and
- the URI "urn:ebu:tt:distribution:2014-01" SHOULD each be carried in an <code>ebuttm:conformsToStandard</code> element as specified in
- [[!EBU-TT-D]].
-
- </p>
-
- <p>The <code>ttp:profile</code> element SHALL NOT be present.</p>
-
- </td>
- </tr>
-
- <tr>
- <td><code>#showBackground</code></td>
-
- <td>permitted</td>
-
-<td></td>
- </tr>
-
- <tr>
- <td><code>#structure</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-chained</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-inheritance-content</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-inheritance-region</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-inline</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-nested</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling-referential</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#styling</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#subFrameRate</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#tickRate</code></td>
-
- <td>permitted</td>
-
- <td><code>ttp:tickRate</code> SHALL be present on the <code>tt</code> element if the
- document contains any time expression that uses the <code>t</code> metric.</td>
-
- </tr>
-
- <tr>
- <td><code>#timeBase-clock</code></td>
-
- <td>prohibited</td>
-
-<td></td>
- </tr>
-
- <tr>
- <td><code>#timeBase-media</code></td>
-
- <td>permitted</td>
-
- <td>NOTE: [[TTML1]] specifies that the default timebase is <code>"media"</code> if
- <code>ttp:timeBase</code> is not specified on <code>tt</code>.</td>
-
- </tr>
-
- <tr>
- <td><code>#timeBase-smpte</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-clock-with-frames</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-clock</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-offset-with-frames</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-offset-with-ticks</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#time-offset</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#timeContainer</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#timing</code></td>
-
- <td>permitted</td>
-<td>
- <ul class="short-list"><li>All time expressions within a <a>Document Instance</a> SHOULD use the same syntax, either
- <code>clock-time</code> or <code>offset-time</code>.</li>
-
- <li>For any content element that contains <code>br</code> elements or text nodes or a
- <code>smpte:backgroundImage</code> attribute, the <code>begin</code> and <code>end</code> attributes SHOULD
- be specified on the content element or at least one of its ancestors.</li></ul>
- </td>
- </tr>
-
- <tr>
- <td><code>#transformation</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#visibility-block</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#visibility-region</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode-horizontal-lr</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode-horizontal-rl</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode-horizontal</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#zIndex</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <th style="text-align:center">Extension</th>
- <th style="text-align:center">Disposition</th>
- <th style="text-align:center">Provisions</th>
- </tr>
-
- <tr>
- <td style="text-align:center" colspan="3"><em>Relative to the IMSC 1.0 Extension namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#aspectRatio</code></td>
-
- <td>permitted</td>
-
-<td></td>
- </tr>
-
- <tr>
- <td><code>#forcedDisplay</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#progressivelyDecodable</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#altText</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
- </tbody>
- </table>
-
- <p class='note'>As specified in [[!TTML1]], 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>
- </section>
- </section>
-
- <section id='text-profile-constraints'>
- <h2>Text Profile Constraints</h2>
-
- <section id='text-profile-designator'>
- <h3>Profile Designator</h3>
-
- <p>This profile is associated with the following profile designator:</p>
-
- <table class='simple'>
- <thead>
- <tr>
- <th>Profile Name</th>
-
- <th>Profile Designator</th>
- </tr>
- </thead>
-
- <tbody>
- <tr>
- <td>IMSC 1.0 Text</td>
-
- <td><code>http://www.w3.org/ns/ttml/profile/imsc1/text</code></td>
- </tr>
- </tbody>
- </table>
-
- <p class='note'>As specified in <a href="#common-features"></a>, the presence of the <code>ttp:profile</code> attribute is
- not required by this profile. The profile designator specified above is intended to be generally used to signal conformance
- of a <a>Document Instance</a> to the profile. The details of such signaling depends on the application, and can, for instance, use
- metadata structures out-of-band of the <a>Document Instance</a>.</p>
- </section>
-
- <section>
- <h3>Recommended Character Sets</h3>
-
- <p>A <a>Document Instance</a> SHOULD be authored using characters selected from the sets specified in <a href=
- "#recommended-unicode-code-points-per-language"></a>.</p>
- </section>
-
- <section>
- <h3>Reference Fonts</h3>
-
- <p>The flow of text within a region depends the dimensions and spacing (kerning) between individual glyphs.
- The following allows, for instance, region extents to be set such that text flows without clipping.</p>
-
- <p>When rendering codepoints matching one of the combinations of computed font family and codepoints listed in
- <a href="#reference-fonts"></a>, a processor SHALL use a font that generates a glyph sequence whose dimension is substantially
- identical to the glyph sequence that would have been generated by one of the specified reference fonts.</p>
-
- <p class="note">Implementations can use fonts other than those specified in <a href="#reference-fonts"></a>. Two fonts
- with equal metrics can have a different appearance, but flow identically.</p>
-
- </section>
+ <head>
+ <meta charset="utf-8" />
+ <title>Redirect to Editor's Draft of IMSC1</title>
+ <meta http-equiv="REFRESH" content="5; url=https://rawgit.com/w3c/imsc1/master/spec/ttml-ww-profiles.html" />
+ </head>
+ <body>
+ <p>The IMSC1 repository has been permanently moved to
+ <a href="https://github.com/w3c/imsc1">https://github.com/w3c/imsc1</a>.</p>
- <section>
- <h3>Features</h3>
-
- <p>See <a href="#conformance"></a> for a definition of "permitted" and "prohibited".</p>
-
- <table class='simple'>
- <tbody>
- <tr>
- <th style="text-align:center">Feature</th>
-
- <th style="text-align:center">Disposition</th>
-
- <th style="text-align:center">Additional provisions</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the TT Feature namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#backgroundColor-block</code></td>
-
- <td>permitted</td>
- <td></td>
- </tr>
-
- <tr>
- <td><code>#backgroundColor-inline</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#backgroundColor-region</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#backgroundColor</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#bidi</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#color</code></td>
-
- <td>permitted</td>
- <td>The initial value of <code>tts:color</code> SHALL be "white". NOTE: This is consistent with
- [[ST2052-1]].</td>
- </tr>
-
- <tr>
- <td><code>#direction</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#displayAlign</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#extent-region</code></td>
-
- <td>permitted</td>
- <td>When applied to a region element, the <code>tts:extent</code> attribute SHALL use <code>px</code> units or
- "percentage" representation, and SHALL NOT use <code>em</code> units.</td>
- </tr>
-
- <tr>
- <td><code>#fontFamily-generic</code></td>
-
- <td>permitted</td>
- <td>A <code>tts:fontFamily</code> of either <code>"monospaceSerif"</code> or <code>"proportionalSansSerif"</code> SHOULD be
- specified for all presented text content. A tts:fontFamily of <code>"default"</code> SHALL be equivalent to <code>"monospaceSerif"</code>.</td>
- </tr>
-
- <tr>
- <td><code>#fontFamily-non-generic</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontFamily</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontSize-anamorphic</code></td>
-
- <td>prohibited</td>
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontSize-isomorphic</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontSize</code></td>
-
- <td></td><td>See <code>#fontSize-anamorphic</code> and <code>#fontSize-isomorphic</code>.</td>
- </tr>
-
- <tr>
- <td><code>#fontStyle-italic</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontStyle-oblique</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontStyle</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontWeight-bold</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#fontWeight</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#length-em</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#lineBreak-uax14</code></td>
-
- <td></td>
-
- <td>The <a>processor</a> SHALL implement the <code>#lineBreak-uax14</code> feature defined in the TT Feature namespace.</td>
- </tr>
-
- <tr>
- <td><code>#lineHeight</code></td>
-
- <td>permitted</td>
- <td><code><length></code> SHOULD be explicitly specified as there is no uniform implementation of the "normal" value
- at the time of this writing.</td>
- </tr>
-
- <tr>
- <td><code>#nested-div</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#nested-span</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#origin</code></td>
-
- <td>permitted</td>
- <td>The <code>tts:origin</code> attribute SHALL use <code>px</code> units or "percentage" representation, and SHALL NOT
- use <code>em</code> units.</td>
- </tr>
-
- <tr>
- <td><code>#padding-1</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#padding-2</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#padding-3</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#padding-4</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#padding</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textAlign-absolute</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textAlign-relative</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textAlign</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration-over</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration-through</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration-under</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textOutline-blurred</code></td>
-
- <td>prohibited</td>
-
-<td></td>
- </tr>
-
- <tr>
- <td><code>#textOutline-unblurred</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#textOutline</code></td>
-
- <td>permitted</td>
- <td>If specified, the border thickness SHALL be 10% or less than the associated font size.</td>
- </tr>
-
- <tr>
- <td><code>#unicodeBidi</code></td>
-
- <td>permitted</td><td></td>
- </tr>
- <tr>
- <td><code>#visibility</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
-
-
- <tr>
- <td><code>#visibility-inline</code></td>
-
- <td>permitted</td>
-<td></td>
- </tr>
- <tr>
- <td><code>#wrapOption</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode-vertical</code></td>
-
- <td>permitted</td><td></td>
- </tr>
-
- <tr>
- <th style="text-align:center">Extension</th>
-
- <th style="text-align:center">Disposition</th>
-
- <th style="text-align:center">Provisions</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the SMPTE-TT Extension Namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#image</code></td>
-
- <td>prohibited</td>
-
-
-<td></td>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the IMSC 1.0 Extension namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#linePadding</code></td>
-
- <td>permitted</td>
-
- <td>
-
- <p>If used, the attribute <code>ebutts:linePadding</code> MAY be specified on elements <code>region</code>, <code>body</code>,
- <code>div</code> and <code>p</code> in addition to <code>style</code>.</p>
-
- <p>The <a>processor</a>:
- <ul class="short-list">
- <li>SHALL apply <code>ebutts:linePadding</code> to <code>p</code> only; and</li>
- <li>SHALL treat <code>ebutts:linePadding</code> as inheritable.</li>
- </ul>
- </p>
-
-
- </td>
- </tr>
-
- <tr>
- <td><code>#multiRowAlign</code></td>
-
- <td>permitted</td>
-
- <td>
- <p>If used, the attribute <code>ebutts:multiRowAlign</code> MAY be specified on elements <code>region</code>, <code>body</code>,
- <code>div</code> and <code>p</code> in addition to <code>style</code></p>
-
- <p>The <a>processor</a>:
- <ul class="short-list">
- <li>SHALL apply <code>ebutts:multiRowAlign</code> to <code>p</code> only; and</li>
- <li>SHALL treat <code>ebutts:multiRowAlign</code> as inheritable.</li>
- </ul>
- </p>
- </td>
- </tr>
- </tbody>
- </table>
-
- <p class='note'>In contrast to this specification, [[!EBU-TT-D]] specifies that the attributes <code>ebutts:linePadding</code> and <code>ebutts:multiRowAlign</code> are allowed only on the <code>style</code> element.</p>
-
- </section>
- </section>
-
- <section id='image-profile-constraints'>
- <h2>Image Profile Constraints</h2>
-
- <section id='image-profile-designator'>
- <h3>Profile Designator</h3>
-
- <p>This profile is associated with the following profile designator:</p>
-
- <table class='simple'>
- <tbody>
- <tr>
- <th>Profile Name</th>
-
- <th>Profile Designator</th>
- </tr>
-
- <tr>
- <td>IMSC 1.0 Image</td>
-
- <td><code>http://www.w3.org/ns/ttml/profile/imsc1/image</code></td>
- </tr>
- </tbody>
- </table>
-
- <p class='note'>As specified in <a href="#common-features"></a>, the presence of the <code>ttp:profile</code> attribute is
- not required by this profile. The profile designator specified above is intended to be generally used to signal conformance
- of a <a>Document Instance</a> to the profile. The details of such signaling depends on the application, and can, for instance, use
- metadata structures out-of-band of the <a>Document Instance</a>.</p>
- </section>
-
- <section>
- <h3>Presented Image</h3>
-
- <section>
- <h4>Definition</h4>
-
- <p>A <dfn>presented image</dfn> is a <code>div</code> element with a <code>smpte:backgroundImage</code> attribute that does
- not extend beyond a <a>presented region</a>.</p>
- </section>
-
- <section>
- <h4>Number per Region</h4>
-
- <p>In a given synchronic document, there shall be at most one <a>presented image</a> per <a>presented region</a>.</p>
-
- </section>
- </section>
-
- <section>
- <h3><code>div</code> element</h3>
-
- <p>If a <code>smpte:backgroundImage</code> attribute is applied to a <code>div</code> element:
-
- <ul>
- <li>the width and height of the image source referenced by <code>smpte:backgroundImage</code> SHALL be equal to width and height of the extent of the region in which the <code>div</code> element is presented;</li>
-
- <li>the <code>div</code> element SHOULD contain a <code>metadata</code> element containing an <code>ittm:altText</code> element that is a <a>text alternative</a> of the image referenced by the <code>smpte:backgroundImage</code> attribute; and</li>
-
- <li>The <code>smpte:backgroundImage</code> attribute SHALL reference a PNG datastream as specified in [[!PNG]]. If a pHYs chunk is present, it SHALL indicate square pixels. Note:
- If no pixel aspect ratio is carried, the default of square pixels is assumed.<br></li>
- </ul>
-
- </p>
-
- <p class='note'>In [[!TTML1]], <code>tts:extent</code> and <code>tts:origin</code> do not apply to <code>div</code> elements. In order to individually position multiple <code>div</code> elements, each <code>div</code> can be associated with a distinct <code>region</code> with the desired <code>tts:extent</code> and <code>tts:origin</code>.</p>
- </section>
-
- <section>
- <h3>Features</h3>
-
- <p>See <a href="#conformance"></a> for a definition of "permitted" and "prohibited".</p>
-
- <table class='simple'>
- <tbody>
- <tr>
- <th style="text-align:center">Feature</th>
-
- <th style="text-align:center">Disposition</th>
-
- <th style="text-align:center">Additional provisions</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the TT Feature namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#bidi</code></td>
-
- <td></td>
-
- <td>See implied features: some are prohibited, others are permitted.</td>
- </tr>
-
- <tr>
- <td><code>#color</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#content</code></td>
-
- <td>permitted</td>
-
- <td>The <code>p</code>, <code>span</code> and <code>br</code> elements SHALL NOT be present.</td>
- </tr>
-
- <tr>
- <td><code>#direction</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#displayAlign</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontFamily</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontSize</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontStyle</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#fontWeight</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#length-em</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#lineBreak-uax14</code></td>
-
- <td></td>
-
- <td>No processor requirement is specified.</td>
- </tr>
-
- <tr>
- <td><code>#lineHeight</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#nested-div</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#nested-span</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#padding</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#textAlign</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#textDecoration</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#textOutline</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#unicodeBidi</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#visibility</code></td>
-<td></td>
- <td>See implied features: some are prohibited, others are permitted.</td>
-
- </tr>
-
-
- <tr>
- <td><code>#visibility-inline</code></td>
-
- <td>prohibited</td>
-<td></td>
- </tr>
-
- <tr>
- <td><code>#wrapOption</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <td><code>#writingMode</code></td>
-
- <td></td>
-
- <td>See implied features: some are prohibited, others are permitted.</td>
-
- </tr>
-
- <tr>
- <td><code>#writingMode-vertical</code></td>
-
- <td>prohibited</td>
-
- <td></td>
- </tr>
-
- <tr>
- <th style="text-align:center">Extension</th>
- <th style="text-align:center">Disposition</th>
- <th style="text-align:center">Provisions</th>
- </tr>
-
- <tr>
- <td colspan="3" style="text-align:center"><em>Relative to the SMPTE-TT Extension namespace</em></td>
- </tr>
-
- <tr>
- <td><code>#image</code></td>
-
- <td>permitted</td>
-
- <td><ul class="short-list">
- <li><code>smpte:backgroundImage</code> MAY be used.</li>
- <li><code>smpte:backgroundImageHorizontal</code> and <code>smpte:backgroundImageVertical</code> SHALL NOT be used.</li>
- <li><code>smpte:image</code> SHALL NOT be used.</li></td>
- </tr>
- </tbody>
- </table>
- </section>
- </section>
-
- <section id='hypothetical-render-model'>
- <h2>Hypothetical Render Model</h2>
-
- <section>
-
- <h3>Overview (non-normative)</h3>
-
- <p>This Section specifies the Hypothetical Render Model illustrated in <a href="#fig-hypothetical-render-model"></a>.</p>
-
- <p>The purpose of the model is to limit <a>Document Instance</a> complexity. It is not intended as a specification of the
- processing requirements for implementations. 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 neither requires the implementation of such a
- buffer, nor models the sub-pixel character positioning and anti-aliased glyph rendering that can be used to produce text
- output.</p>
-
- <figure id='fig-hypothetical-render-model'>
- <img src="hypothetical-render-figure-1.png" alt="Hypothetical Render Model">
-
- <figcaption>
- Hypothetical Render Model
- </figcaption>
- </figure>
-
- <p>The model operates on successive <a data-lt="intermediate synchronic document">intermediate synchronic documents</a>
- obtained from an input <a>Document Instance</a>, and uses a simple double buffering model: while an <a>intermediate synchronic
- document</a> E<sub>n</sub> is being painted into Presentation Buffer P<sub>n</sub> (the "front buffer" of the model), the
- previous <a>intermediate synchronic document</a> 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 <a>intermediate synchronic document</a>
- 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 <a>intermediate synchronic document</a>
- E<sub>n</sub> completes before the end of <a>intermediate synchronic document</a> 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 <a>Related Video Object</a> resolution.</p>
-
- <p>To enable scenarios where the same glyphs are used in multiple successive <a data-lt=
- "intermediate synchronic document">intermediate synchronic documents</a>, e.g. to convey a CEA-608/708-style roll-up (see
- [[CEA-608]] and [[CEA-708]]), the Glyph Buffers G<sub>n</sub> and G<sub>n-1</sub> store rendered glyphs across <a data-lt=
- "intermediate synchronic document">intermediate synchronic documents</a>, 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='hypothetical-render-model-general'>
- <h3>General</h3>
-
- <p>The Presentation Compositor SHALL 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 <a>intermediate synchronic document</a> E<sub>0</sub> for the which the pixels
- of P<sub>0</sub> SHALL 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 SHALL 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; or</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 <a>intermediate synchronic document</a> E<sub>n</sub> in the
- Presentation Buffer P<sub>n</sub> SHALL be:</p>
-
- <p class="equation">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 <a>intermediate synchronic document</a> E<sub>n</sub>, as
- specified in <a href="#paint-regions"></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 href="#paint-text"></a>; and
- </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 href="#paint-images">.</a>
- </li>
- </ul>
-
- <p>The contents of the Presentation Buffer P<sub>n</sub> SHALL be transferred instantaneously to Presentation Buffer
- P<sub>n-1</sub> at the presentation time of <a>intermediate synchronic document</a> E<sub>n</sub>, making the latter
- available for display.</p>
-
- <p class='note'>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 <a>Related Video Object</a>.</p>
-
- <p>It SHALL 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 SHALL 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>
-
- <p class='note'>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>
-
- <p class='note'>IPD effectively sets a limit on the complexity of any given <a>intermediate synchronic document</a>.</p>
- </section>
-
- <section id='paint-regions'>
- <h3>Paint Regions</h3>
-
- <p>The total normalized drawing area S(E<sub>n</sub>) for <a>intermediate synchronic document</a> E<sub>n</sub> SHALL
- be</p>
-
- <p class="equation">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>
-
- <p class='note'>To ensure consistency of the Presentation Buffer, a new <a>intermediate synchronic document</a> requires
- clearing of the root container.</p>
-
- <p>PAINT(E<sub>n</sub>) SHALL 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 class="equation">PAINT(E<sub>n</sub>) = ∑<sub>R<sub>i</sub>∈R<sub>p</sub></sub> NSIZE(R<sub>i</sub>) ∙ NBG(R<sub>i</sub>)</p>
-
- <p>where R_p SHALL be the set of <a data-lt="presented region">presented regions</a> in the <a>intermediate synchronic
- document</a> E<sub>n</sub>.</p>
-
- <p>NSIZE(R<sub>i</sub>) SHALL be given by:</p>
-
- <p class="equation">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'>
- 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>) SHALL be the total number of <code>tts:backgroundColor</code> attributes associated with the given
- region R<sub>i</sub> in the <a>intermediate synchronic document</a>. 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; or</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 <a>intermediate synchronic document</a> (see [[!TTML1]] for more
- details on when a content element is followed into a region); or
- </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 <a>intermediate synchronic document</a> (see [[!TTML1]] 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> SHALL require an additional fill operation for all
- region pixels.</p>
- </section>
-
- <section id='paint-images'>
- <h3>Paint Images</h3>
-
- <p>The Presentation Compositor SHALL paint into the Presentation Buffer P<sub>n</sub> all visible pixels of presented
- images of <a>intermediate synchronic document</a> E<sub>n</sub>.</p>
-
- <p>For each <a>presented image</a>, the Presentation Compositor SHALL 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 <a>
- intermediate synchronic document</a> E<sub>n-1</sub>, copy using the Image Copier the image 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 SHALL 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 <a>intermediate synchronic document</a>
- E<sub>n</sub> in the Presentation Buffer SHALL be as follows:</p>
-
- <p class="equation">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 <a>intermediate synchronic document</a> E<sub>n</sub>;
- </li>
-
- <li>I<sub>d</sub> is the set of images decoded when painting <a>intermediate synchronic document</a> E<sub>n</sub>;
- </li>
-
- <li>IDec is the image decoding rate; and</li>
-
- <li>ICpy is the normalized image copy performance factor.</li>
- </ul>
-
- <p>NRGA(I<sub>i</sub>) is the Normalized Image Area of <a>presented image</a> I<sub>i</sub> and SHALL be equal to:</p>
-
- <p class="equation">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>) SHALL be the number of pixels of <a>presented image</a> I<sub>i</sub>.</p>
-
- <p>The contents of the Decoded Image Buffer D<sub>n</sub> SHALL be transferred instantaneously to Decoded Image Buffer
- D<sub>n-1</sub> at the presentation time of <a>intermediate synchronic document</a> 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> SHALL 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> SHALL be the Normalized Decoded Image Buffer Size
- (NDIBS).</p>
-
- <p>Unless specified otherwise, the following table SHALL 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'>
- <h3>Paint Text</h3>
-
- <p>In the context of this section, a <dfn>glyph</dfn> is a tuple consisting of (i) one character and (ii) the computed values of the following
- style properties:
-
- <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>
-
- </p>
-
- <p class='note'>In complex scripts, the mapping from character to typographical glyph is not one-to-one. For instance, a given arabic character can
- yield multiple glyphs depending on its position in a word. The Hypothetical Render Model however assumes a one-to-one mapping
- and accounts for complex scripts by reducing the performance of the glyph buffer.</p>
-
- <p>For each <a>glyph</a> associated with a character in a <a>presented region</a> of <a>intermediate synchronic document</a> E<sub>n</sub>,
- the Presentation Compositor SHALL:</p>
-
- <ul>
- <li>if an identical <a>glyph</a> is present in Glyph Buffer G<sub>n</sub>, copy the <a>glyph</a> 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 <a>glyph</a> is present in Glyph Buffer G<sub>n-1</sub>, i.e. an identical <a>glyph</a> was present in <a>intermediate
- synchronic document</a> E<sub>n-1</sub>, copy using the Glyph Copier the <a>glyph</a> 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 <a>glyph</a> into the Presentation Buffer P<sub>n</sub> and Glyph Buffer
- G<sub>n</sub>.</li>
- </ul>
-
- <figure>
- <img src="text-render-example-figure-2.png" alt="Example of Presentation Compositor Behavior for Text Rendering" height=
- "150" width="324">
-
- <figcaption>
- Example of Presentation Compositor Behavior for Text Rendering
- </figcaption>
- </figure>
-
- <p>The duration DUR<sub>T</sub>(E<sub>n</sub>) for rendering the text of an <a>intermediate synchronic document</a>
- E<sub>n</sub> in the Presentation Buffer is as follows:</p>
-
- <p class="equation">DUR<sub>T</sub>(E<sub>n</sub>) = ∑<sub>g<sub>i</sub> ∈ Γ<sub>r</sub></sub> NRGA(g<sub>i</sub>) / Ren(g<sub>i</sub>)
- + ∑<sub>g<sub>j</sub> ∈ Γ<sub>c</sub></sub> NRGA(g<sub>j</sub>) / GCpy</p>
-
- <p>where</p>
-
- <ul>
- <li>Γ<sub>r</sub> is the set of <a data-lt="glyph">glyphs</a> rendered into the Presentation Buffer P<sub>n</sub> using the Glyph Renderer in
- <a>intermediate synchronic document</a> E<sub>n</sub>;
- </li>
-
- <li>Γ<sub>c</sub> is the set of <a data-lt="glyph">glyphs</a> copied to the Presentation Buffer P<sub>n</sub> using the Glyph Copier in
- <a>intermediate synchronic document</a> E<sub>n</sub>;
- </li>
-
- <li>Ren(g<sub>i</sub>) is the text rendering performance factor for <a>glyph</a> g<sub>i</sub>; and</li>
-
- <li>GCpy is the normalized glyph copy performance factor.</li>
- </ul>
-
- <p>The Normalized Rendered Glyph Area NRGA(g<sub>i</sub>) of a <a>glyph</a> g<sub>i</sub> SHALL be equal to:</p>
-
- <p class="equation">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> SHALL be copied instantaneously to Glyph Buffer G<sub>n-1</sub> at the
- presentation time of <a>intermediate synchronic document</a> E<sub>n</sub>.</p>
-
- <p>It SHALL be an error for the sum of NRGA(g<sub>i</sub>) over all <a data-lt="glyph">glyphs</a> Glyph Buffer G<sub>n</sub> to be larger
- than the Normalized Glyph Buffer Size (NGBS).</p>
-
- <p>Unless specified otherwise, the following table specifies values of GCpy, Ren and NGBS.</p>
-
- <table class='simple'>
- <thead>
- <tr>
- <th style="text-align: center;">Parameter</th>
-
- <th style="text-align: center;">Condition</th>
-
- <th style="text-align: center;">Initial value</th>
- </tr>
- </thead>
-
- <tbody>
- <tr>
- <td rowspan="2">Normalized glyph copy performance factor (GCpy)</td>
-
- <td>The character of g<sub>i</sub> belongs to a simple script as specified in <a href="#simple-scripts"></a></td>
-
- <td>12</td>
- </tr>
-
- <tr>
-
- <td>otherwise</td>
-
- <td>3</td>
- </tr>
-
- <tr>
- <td rowspan="2">Text rendering performance factor Ren(G<sub>i</sub>)</td>
- <td>The character of g<sub>i</sub> belongs to the CJK Unified Ideograph block as specified in [[!UNICODE]]</td>
-
- <td>0.6</td>
- </tr>
-
- <tr>
- <td>otherwise</td>
-
- <td>1.2</td>
- </tr>
-
- <tr>
- <td colspan="2">Normalized Glyph Buffer Size (NGBS)</td>
-
- <td>1</td>
- </tr>
- </tbody>
- </table>
-
- <p class='note'>NRGA(G<sub>i</sub>) does not take into account decorations (e.g. underline), effects (e.g.
- outline) or actual typographical glyph aspect ratio. An implementation can determine an actual buffer size needs based on worst-case
- glyph size complexity.</p>
-
- <aside class='example'>
- Setting a Normalized Glyph Buffer Size effectively sets a limit on the total number of distinct <a data-lt="glyph">glyphs</a> present in any
- given <a>intermediate synchronic document</a> 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 font size relative to the root container height is 1/15 , and
- the maximum number of distinct glyphs that can be buffered is 1÷(1÷15)^2=225 glyphs.
- </aside>
-
- <aside class='example'>
- GCpy effectively sets a limit on animating text. 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 <a>intermediate synchronic document</a>), a GCpy and BDraw of 12 s-1
- would mean that a group of 160 <a data-lt="glyph">glyphs</a> 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'>
- Ren(G<sub>i</sub>) effectively sets a limit on the text 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 <a data-lt="glyph">glyphs</a> 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>
-</section>
-
- <section class='appendix' id="reference-fonts">
- <h2>Reference Fonts</h2>
-
-
-
- <table class='simple'>
- <thead>
- <tr>
- <th>Computed Font Family</th>
-
- <th>Code Points</th>
-
- <th>Reference Font</th>
- </tr>
- </thead>
-
- <tbody>
- <tr>
- <td><code>monospaceSerif</code></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">Courier New</a>
- or
- <a href="https://fedorahosted.org/liberation-fonts/">Liberation Mono</a>
- </td>
- </tr>
-
- <tr>
- <td><code>proportionalSansSerif</code></td>
-
- <td>
- All code points specified in <a href="#recommended-unicode-code-points-per-language"></a>, excluding the code points
- defined for Hebrew and Arabic scripts.
- </td>
-
- <td>
- <a href=
- "http://www.microsoft.com/typography/fonts/family.aspx?FID=8">Arial</a> or <a href=
- "http://www.linotype.com/en/526/Helvetica-family.html">Helvetica</a> or <a href=
- "https://fedorahosted.org/liberation-fonts/">Liberation Sans</a>
- </td>
- </tr>
- </tbody>
- </table>
-
- </section>
-
-
- <section class='appendix' id='recommended-unicode-code-points-per-language'>
- <h2>Recommended Character Sets</h2>
-
- <p>When authoring textual content, authors are encouraged to select from sets of characters based on the language indicated
- using <code>xml:lang</code>. 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, an author SHOULD choose characters from the set resulting from the union of the
- following sets:</p>
-
- <ul>
- <li>the main exemplar character set specified for the language in [[!CLDR]] as well as any corresponding uppercase characters as specified in [[!UNICODE]]; and</li>
-
- <li>the punctuation exemplar character set specified for the language in [[!CLDR]];</li>
-
- <li>the digits and symbols included in all numberSystems specified for the language in [[!CLDR]];</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>
- </ul>
-
- <p>Some of these sets overlap.</p>
-
- <p>Table 1 captures the set of characters intended to be available to authors across all languages. The terms used in the table
- are defined in [[!UNICODE]].</p>
-
- <table class='simple'>
- <caption>
- Table 1. Common Character Set.
- </caption>
-
- <tr>
- <th>(Basic Latin)</th>
- </tr>
-
- <tr>
- <td>U+0020 - U+007E</td>
- </tr>
-
- <tr>
- <th>(Latin-1 Supplement)</th>
- </tr>
-
- <tr>
- <td>U+00A0 - U+00FF</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>(Latin Extended-B)</th>
- </tr>
-
- <tr>
- <td>U+0192 : LATIN SMALL LETTER F WITH HOOK</td>
- </tr>
-
- <tr>
- <th>(Spacing Modifier Letters)</th>
- </tr>
-
- <tr>
- <td>U+02DC : SMALL TILDE</td>
- </tr>
-
- <tr>
- <th>(Combining Diacritical Marks)</th>
- </tr>
-
- <tr>
- <td>U+0301 : COMBINING ACUTE ACCENT</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>(Currency symbols)</th>
- </tr>
-
- <tr>
- <td>U+20AC : EURO SIGN</td>
- </tr>
-
- <tr>
- <th>(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>(Number Forms)</th>
- </tr>
-
- <tr>
- <td>U+2153 - U+215F : Fractions</td>
- </tr>
-
- <tr>
- <th>(Mathematical Operators)</th>
- </tr>
-
- <tr>
- <td>U+2212 : MINUS SIGN</td>
- </tr>
-
- <tr>
- <td>U+221E : INFINITY</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>(Block Elements)</th>
- </tr>
-
- <tr>
- <td>U+2588 : FULL BLOCK</td>
- </tr>
-
- <tr>
- <th>(Geometric Shapes)</th>
- </tr>
-
- <tr>
- <td>U+25A1 : WHITE SQUARE</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>
-
- </table><br>
-
- <p>Table 2 specifies supplementary character set that have proven useful in captioning and subtitling applications for a number
- of selected languages. Table 2 is non-exhaustive, and will be extended as needs arise.</p>
-
- <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>sq, fi, da, nl, en, de, is, no, sv, ca, fr, it</td>
-
- <td><em>no supplementary characters</em></td>
- </tr>
-
- <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>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+0308<br>
- (Greek and Coptic)<br>
- U+0386 - U+038A<br>
- U+038C<br>
- U+038E - U+03A1<br>
- U+03A3 - 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+0609<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, uk</td>
-
- <td>(Latin Extended-A)<br>
- U+0100 - U+017F<br>
-
- (Spacing Modifier Letters)<br>
- U+02BC<br>
-
- (Cyrillic)<br>
- U+0400 - U+045F<br>
- U+048A - U+04F9<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+048A - U+04F9</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 class='appendix' id='forced-content'>
- <h2>Forced content (non-normative)</h2>
-
- <p><a href='#fig-forced-content'></a> below illustrates the use of forced content, i.e. <code>itts:forcedDisplay</code> and
- <code>displayForcedOnlyMode</code>. The content with <code>itts:forcedDisplay</code>="true" is the French translation of the
- "High School" sign. The content with <code>itts:forcedDisplay</code>="false" are French subtitles capturing a voiceover.</p>
-
- <figure id='fig-forced-content'>
- <img src="forced-example-figure-1.png" alt="Illustration of the use of itts:forcedDisplay">
-
- <figcaption>
- Illustration of the use of itts:forcedDisplay
- </figcaption>
- </figure>
-
- <p>When the user selects French as the playback language but does not select French subtitles,
- <code>displayForcedOnlyMode</code> is set to "true", causing the display of the sign translation, which is useful to any French
- speaker, but hiding the voiceover subtitles as the voiceover is heard in French.</p>
-
- <p>If the user selects French as the playback language and also selects French subtitles, e.g. if the user is hard-of-hearing,
- <code>displayForcedOnlyMode</code> is set to "false", causing the display of both the sign translation and the voiceover
- subtitles.</p>
-
- <p>The algorithm for setting the <code>displayForcedOnlyMode</code> parameter and selecting the appropriate combination of
- subtitle and audio tracks depends on the application.</p>
- </section>
-
- <section class='appendix' id='wcag-applications'>
- <h2>WCAG Considerations</h2>
-
- <p>In order to meet the guidelines in [[!WCAG20]], the following considerations apply.</p>
-
- <p>Guideline 1.1 of [[!WCAG20]] recommends that an implementation provide text alternatives for all non-text content. In the
- context of this specification, this text alternative is intended primarily to support users of the subtitles who cannot see
- images. Since the images of an <a>Image Profile</a> <a>Document Instance</a> usually represent subtitle or caption text, the
- guidelines for authoring text equivalent strings given at <span class='sec-no'>Images of text</span> of [[HTML5]] are
- appropriate.</p>
-
- <p>Thus, for each subtitle in an <a>Image Profile</a> <a>Document Instance</a>, a text equivalent content in a <a>Text Profile</a>
- <a>Document Instance</a> SHOULD be written so that it conveys all essential content and fulfills the same function as the
- corresponding subtitle image. In the context of subtitling and captioning, this content will be (as a minimum) the verbatim
- equivalent of the image without précis or summarization. However, the author MAY include extra information to the text
- equivalent string in cases where styling is applied to the text image with a deliberate connotation, as a <em>functional</em>
- replacement for the applied style.</p>
-
- <p>For instance, in subtitling and captioning, italics can be used to indicate an off screen speaker context (for example a
- voice from a radio). An author can choose to include this functional information in the text equivalent; for example, by
- including the word "Radio: " before the image equivalent text. Note that images in an <a>Image Profile</a>
- <a>Document Instance</a> that are intended for use as <em>captions</em>, i.e. intended for a hard of hearing audience, might already
- include this functional information in the rendered text.</p>
-
- <p>Guideline 1.1 of [[!WCAG20]] also recommends that accessible text alternatives must be "programmatically determinable." This
- means that the text must be able to be read and used by the assistive technologies (and the accessibility features in browsers)
- that people with disabilities use. It also means that the user must be able to use their assistive technology to find the
- alternative text (that they can use) when they land on the non-text content (that they can't use).</p>
- </section>
-
- <section class='appendix' id='sample-instance'>
- <h2>Sample Document Instance (non-normative)</h2>
-
- <p>The following sample <a data-lt='Document Instance'>Document Instances</a> conforms to the Text and Image Profiles, respectively. These samples are for illustration only, and are neither intended to capture current or future practice, nor exercise all normative prose contained in this specification.</p>
-
-<pre class='example'>
-<?xml version="1.0" encoding="UTF-8"?>
-<tt
- xml:lang="en" xmlns="http://www.w3.org/ns/ttml"
- xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
- xmlns:tts="http://www.w3.org/ns/ttml#styling"
- xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
- xmlns:ittp="http://www.w3.org/ns/ttml/profile/imsc1#parameter"
- ittp:aspectRatio="4 3">
-
- <head>
- <layout>
- <region xml:id="area1" tts:origin="10% 10%" tts:extent="80% 10%" tts:backgroundColor="black" tts:displayAlign="center" tts:color="red"/>
- </layout>
- </head>
- <body>
- <div>
- <p region="area1" begin="0s" end="6s">Lorem ipsum dolor sit amet.</p>
- </div>
- </body>
-</tt>
-</pre>
-
-
-<pre class='example'>
-<?xml version="1.0" encoding="UTF-8"?>
-<tt
- xmlns="http://www.w3.org/ns/ttml"
- xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
- xmlns:tts="http://www.w3.org/ns/ttml#styling"
- xmlns:ttp="http://www.w3.org/ns/ttml#parameter"
- xmlns:smpte="http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt"
- xmlns:itts="http://www.w3.org/ns/ttml/profile/imsc1#styling"
- tts:extent="640px 480px"
- ttp:frameRate="25"
- xml:lang="fr">
-
- <head>
- <layout>
- <region xml:id="region1" tts:origin="120px 410px" tts:extent="240px 40px" tts:showBackground="whenActive"/>
- <region xml:id="region2" tts:origin="120px 20px" tts:extent="240px 40px" tts:showBackground="whenActive"/>
- </layout>
- </head>
- <body>
- <div region="region1" begin="00:00:01:00" end="00:00:02:00" smpte:backgroundImage="1.png"/>
- <div region="region1" begin="00:00:03:20" end="00:00:04:12" smpte:backgroundImage="2.png"/>
- <div region="region2" itts:forcedDisplay="true" begin="00:00:03:20" end="00:00:04:12" smpte:backgroundImage="3.png"/>
- </body>
-</tt>
-</pre>
- </section>
-
- <section class='appendix' id='features-and-extensions'>
- <h2>Extensions</h2>
-
- <section class='appendix'>
- <h3>General</h3>
-
- <p>The following sections define extension designations, expressed as relative URIs (fragment identifiers) relative to the
- IMSC 1.0 Extension Namespace base URI.</p>
- </section>
-
- <section class='appendix'>
- <h3>#progressivelyDecodable</h3>
-
- <p>A <a>transformation processor</a> supports the <code>#progressivelyDecodable</code> feature if it recognizes and is
- capable of transforming values of the <a href="#ttp-progressivelyDecodable"><code>ittp:progressivelyDecodable</code></a>.</p>
-
- <p>A <a>presentation processor</a> supports the <code>#progressivelyDecodable</code> feature if it implements presentation
- semantic support for values of the <a href="#ttp-progressivelyDecodable"><code>ittp:progressivelyDecodable</code></a>
- attribute.</p>
- </section>
-
- <section class='appendix'>
- <h3>#aspectRatio</h3>
-
- <p>A <a>transformation processor</a> supports the <code>#aspectRatio</code> feature if it recognizes and is capable of
- transforming values of the <a href="#ttp-aspectRatio"><code>ittp:aspectRatio</code></a>.</p>
-
- <p>A <a>presentation processor</a> supports the <code>#aspectRatio</code> feature if it implements presentation semantic
- support for values of the <a href="#ttp-aspectRatio"><code>ittp:aspectRatio</code></a> attribute.</p>
- </section>
-
- <section class='appendix'>
- <h3>#forcedDisplay</h3>
-
- <p>A <a>transformation processor</a> supports the <code>#forcedDisplay</code> feature if it recognizes and is capable of
- transforming values of the <a href="#tts-forcedDisplay"><code>itts:forcedDisplay</code></a>.</p>
-
- <p>A <a>presentation processor</a> supports the <code>#forcedDisplay</code> feature if it implements presentation semantic
- support for values of the <a href="#tts-forcedDisplay"><code>itts:forcedDisplay</code></a> attribute.</p>
- </section>
-
- <section class='appendix'>
- <h3>#altText</h3>
-
- <p>A <a>transformation processor</a> supports the <code>#altText</code> feature if it recognizes and is capable of
- transforming values of the <a href="#ttm-altText"><code>ittm:altText</code></a> element.</p>
-
- <p>A <a>presentation processor</a> supports the <code>#altText</code> feature if it implements presentation semantic support
- for values of the <a href="#ttm-altText"><code>ittm:altText</code></a> element.</p>
- </section>
-
- <section class='appendix'>
- <h3>#linePadding</h3>
-
- <p>A <a>transformation processor</a> supports the <code>#linePadding</code> feature if it recognizes and is capable of
- transforming values of the <code>ebutts:linePadding</code> attribute specified in [[!EBU-TT-D]].</p>
-
- <p>A <a>presentation processor</a> supports the <code>#linePadding</code> feature if it implements presentation semantic
- support for values of the <code>ebutts:linePadding</code> attribute specified in [[!EBU-TT-D]].</p>
- </section>
-
- <section class='appendix'>
- <h3>#multiRowAlign</h3>
-
- <p>A <a>transformation processor</a> supports the <code>#multiRowAlign</code> feature if it recognizes and is capable of
- transforming values of the <code>ebutts:multiRowAlign</code> attribute specified in [[!EBU-TT-D]].</p>
-
- <p>A <a>presentation processor</a> supports the <code>#multiRowAlign</code> feature if it implements presentation semantic
- support for values of the <code>ebutts:multiRowAlign</code> attribute specified in [[!EBU-TT-D]].</p>
- </section>
- </section>
-
- <section class='appendix' id='xml-schemas'>
- <h2>XML Schema Definitions (non-normative)</h2>
-
- <p>XML Schema definitions (see [[xmlschema-1]]) for extension vocabulary defined
- by this specification are provided <a href="./xml-schemas">here</a> for convenience.</p>
-
- <p>These definitions are non-normative and are not sufficient to validate conformance of a <a>Document Instance</a>.</p>
-
- <p>In any case where a definition specified by this appendix diverge from the prose of the specification,
- then the latter takes precedence.</p>
-
-
- </section>
-
-
- <section class='appendix' id='simple-scripts'>
- <h2>Simple Scripts</h2>
-
- <p>The following table refers to the value of the script property associated with Unicode characters.</p>
-
- <table class='simple'>
- <thead>
- <tr>
- <th>Simple scripts</th>
-
- </tr>
- </thead>
-
- <tbody>
-
-
- <tr>
-
- <td>
- Latin
- </td>
- </tr>
-
- <tr>
-
- <td>
- Hebrew
- </td>
- </tr>
-
- <tr>
-
- <td>
- Cyrillic
- </td>
- </tr>
-
- <tr>
-
- <td>
- Greek
- </td>
- </tr>
- </tbody>
- </table>
-
-
- </section>
-</body>
+ <p>The latest Editor's Draft can be viewed at
+ <a href="https://rawgit.com/w3c/imsc1/master/spec/ttml-ww-profiles.html">https://rawgit.com/w3c/imsc1/master/spec/ttml-ww-profiles.html</a>,
+ where you will be redirected shortly.</p>
+ </body>
</html>