- From: CVS User spfeiffe <cvsmail@w3.org>
- Date: Thu, 14 Nov 2013 14:09:02 +0000
- To: public-html-commits@w3.org
Update of /sources/public/html5/webvtt
In directory roscoe:/tmp/cvs-serv11328
Modified Files:
Overview.html
Log Message:
Include position/line alignment
--- /sources/public/html5/webvtt/Overview.html 2013/10/28 06:51:18 1.76
+++ /sources/public/html5/webvtt/Overview.html 2013/11/14 14:09:02 1.77
@@ -5,7 +5,7 @@
<meta charset="utf-8">
<!-- local copy:
<script src='../../respec/builds/respec-w3c-common-3.2.4.js' async class='remove'></script>
- -->
+ -->
<!-- remote copy: -->
@@ -280,7 +280,7 @@
</p>
<h1 class="title p-name" id="title" property="dcterms:title">WebVTT: The Web Video Text Tracks Format</h1>
- <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2013-10-27T19:51:08.000Z" id="draft-community-group-specification-28-october-2013">Draft Community Group Specification <time class="dt-published" datetime="2013-10-28">28 October 2013</time></h2>
+ <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2013-11-14T06:08:45.000Z" id="draft-community-group-specification-14-november-2013">Draft Community Group Specification <time class="dt-published" datetime="2013-11-14">14 November 2013</time></h2>
<dl>
@@ -293,6 +293,9 @@
+ <dt>Previous editor's draft:</dt>
+ <dd><a href="http://dev.w3.org/html5/webvtt/">http://dev.w3.org/html5/webvtt/</a></dd>
+
<dt>Editors:</dt>
<dd class="p-author h-card vcard" rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a class="u-url url p-name fn" rel="foaf:homepage" property="foaf:name" content="Silvia Pfeiffer" href="mailto:silviapfeiffer1@gmail.com">Silvia Pfeiffer</a>, <a rel="foaf:workplaceHomepage" class="p-org org h-org h-card" href="http://nicta.com.au/">NICTA</a></span>
@@ -322,6 +325,7 @@
<p>If you wish to make comments or file bugs regarding this document in a manner
that is tracked by the W3C, please submit them via <a href="http://www.w3.org/Bugs/Public/enter_bug.cgi?product=TextTracks%20CG&component=WebVTT&short_desc=%5BWebVTT%5D%20">our
public bug database</a>.</p>
+
</section><section id="sotd" class="introductory" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter"><h2 aria-level="1" role="heading" id="h2_sotd">Status of This Document</h2>
<p>
This specification was published by the <a href="http://www.w3.org/community/texttracks/">Text Tracks Community Group</a>.
@@ -335,7 +339,7 @@
<a href="http://www.w3.org/community/">W3C Community and Business Groups</a>.
</p>
- <p>This specification was originally created by the WHATWG as a Living Standard and last published at <a href="http://dev.w3.org/html5/webvtt/">http://dev.w3.org/html5/webvtt/</a>.
+ <p>This specification is being developed as a Living Specification. There is a plan to take a snapshot and publish it as a W3C Recommendation through the <a href="http://www.w3.org/AudioVideo/TT/">W3C Timed Text Working Group</a>.
</p>
</section><section id="toc"><h2 class="introductory" aria-level="1" role="heading" id="h2_toc">Table of Contents</h2><ul class="toc" role="directory" id="respecContents"><li class="tocline"><a href="#introduction" class="tocxref"><span class="secno">1. </span>Introduction</a><ul class="toc"><li class="tocline"><a href="#cues-with-multiple-lines" class="tocxref"><span class="secno">1.1 </span>Cues with multiple lines</a></li><li class="tocline"><a href="#comments" class="tocxref"><span class="secno">1.2 </span>Comments</a></li><li class="tocline"><a href="#other-features" class="tocxref"><span class="secno">1.3 </span>Other features</a></li></ul></li><li class="tocline"><a href="#conformance" class="tocxref"><span class="secno">2. </span>Conformance</a><ul class="toc"><li class="tocline"><a href="#dependencies" class="tocxref"><span class="secno">2.1 </span>Dependencies</a></li></ul></li><li class="tocline"><a href="#data-model" class="tocxref"><span class="secno">3. </span>Data model</a><ul class="toc"><liclass="tocline"><a href="#text-track-cues" class="tocxref"><span class="secno">3.1 </span>Text Track Cues</a></li><li class="tocline"><a href="#text-track-region" class="tocxref"><span class="secno">3.2 </span>Text Track Region</a></li></ul></li><li class="tocline"><a href="#the-webvtt-file-format-syntax" class="tocxref"><span class="secno">4. </span>The WebVTT file format: Syntax</a><ul class="toc"><li class="tocline"><a href="#webvtt-file-structure" class="tocxref"><span class="secno">4.1 </span>WebVTT file structure</a></li><li class="tocline"><a href="#webvtt-comments" class="tocxref"><span class="secno">4.2 </span>WebVTT comments</a></li><li class="tocline"><a href="#types-of-webvtt-cue-payload" class="tocxref"><span class="secno">4.3 </span>Types of WebVTT cue payload</a><ul class="toc"><li class="tocline"><a href="#webvtt-metadata-text" class="tocxref"><span class="secno">4.3.1 </span>WebVTT metadata text</a></li><li class="tocline"><a href="#webvtt-cue-text" class="tocxref"><span class="secno">4.3.2</span>WebVTT cue text</a></li></ul></li><li class="tocline"><a href="#webvtt-cue-settings" class="tocxref"><span class="secno">4.4 </span>WebVTT cue settings</a><ul class="toc"><li class="tocline"><a href="#webvtt-region-definition" class="tocxref"><span class="secno">4.4.1 </span>WebVTT region definition</a></li><li class="tocline"><a href="#webvtt-cue-settings-1" class="tocxref"><span class="secno">4.4.2 </span>WebVTT cue settings</a></li></ul></li><li class="tocline"><a href="#properties-of-cue-sequences" class="tocxref"><span class="secno">4.5 </span>Properties of cue sequences</a><ul class="toc"><li class="tocline"><a href="#webvtt-file-using-only-nested-cues" class="tocxref"><span class="secno">4.5.1 </span>WebVTT file using only nested cues</a></li></ul></li><li class="tocline"><a href="#types-of-webvtt-files" class="tocxref"><span class="secno">4.6 </span>Types of WebVTT files</a><ul class="toc"><li class="tocline"><a href="#webvtt-file-using-metadata-content" class="tocxref"><span class="secno">4..1 </span>WebVTT file using metadata content</a></li><li class="tocline"><a href="#webvtt-file-using-chapter-title-text" class="tocxref"><span class="secno">4.6.2 </span>WebVTT file using chapter title text</a></li><li class="tocline"><a href="#webvtt-file-using-cue-text" class="tocxref"><span class="secno">4.6.3 </span>WebVTT file using cue text</a></li></ul></li></ul></li><li class="tocline"><a href="#webvtt-file-format-parsing" class="tocxref"><span class="secno">5. </span>WebVTT file format: Parsing</a><ul class="toc"><li class="tocline"><a href="#webvtt-file-parsing" class="tocxref"><span class="secno">5.1 </span>WebVTT file parsing</a></li><li class="tocline"><a href="#webvtt-region-settings-parsing" class="tocxref"><span class="secno">5.2 </span>WebVTT region settings parsing</a></li><li class="tocline"><a href="#webvtt-cue-timings-and-settings-parsing" class="tocxref"><span class="secno">5.3 </span>WebVTT cue timings and settings parsing</a></li><li class="tocline"><a href="#webvtt-cue-text-parsing-ules" class="tocxref"><span class="secno">5.4 </span><span>WebVTT cue text parsing rules</span></a></li><li class="tocline"><a href="#webvtt-cue-text-dom-construction-rules" class="tocxref"><span class="secno">5.5 </span><span>WebVTT cue text DOM construction rules</span></a></li></ul></li><li class="tocline"><a href="#rendering" class="tocxref"><span class="secno">6. </span>Rendering</a><ul class="toc"><li class="tocline"><a href="#cues-in-isolation" class="tocxref"><span class="secno">6.1 </span>Cues in isolation</a></li><li class="tocline"><a href="#cues-with-video" class="tocxref"><span class="secno">6.2 </span>Cues with video</a><ul class="toc"><li class="tocline"><a href="#processing-model" class="tocxref"><span class="secno">6.2.1 </span>Processing model</a></li><li class="tocline"><a href="#applying-css-properties-to-webvtt-node-objects" class="tocxref"><span class="secno">6.2.2 </span>Applying CSS properties to <span title="WebVTT Node Object" class="formerLink">WebVTT Node Objects</span></a></li><i class="tocline"><a href="#css-extensions" class="tocxref"><span class="secno">6.2.3 </span>CSS extensions</a><ul class="toc"><li class="tocline"><a href="#the-cue-pseudo-element" class="tocxref"><span class="secno">6.2.3.1 </span>The '::cue' pseudo-element</a></li><li class="tocline"><a href="#the-past-and-future-pseudo-classes" class="tocxref"><span class="secno">6.2.3.2 </span>The ':past' and ':future' pseudo-classes</a></li><li class="tocline"><a href="#the-cue-region-pseudo-element" class="tocxref"><span class="secno">6.2.3.3 </span>The '::cue-region' pseudo-element</a></li></ul></li></ul></li></ul></li><li class="tocline"><a href="#webvtt-api-for-browsers" class="tocxref"><span class="secno">7. </span>WebVTT API for Browsers</a><ul class="toc"><li class="tocline"><a href="#vttcue-interface" class="tocxref"><span class="secno">7.1 </span>VTTCue interface</a></li><li class="tocline"><a href="#extension-of-the-texttrack-interface-for-region-support" class="tocxref"><span class="secno">7.2 </span>Extensin of the TextTrack interface for region support</a></li><li class="tocline"><a href="#vttregion-interface" class="tocxref"><span class="secno">7.3 </span>VTTRegion interface</a></li><li class="tocline"><a href="#vttregionlist-interface" class="tocxref"><span class="secno">7.4 </span>VTTRegionList interface</a></li></ul></li><li class="tocline"><a href="#iana-considerations" class="tocxref"><span class="secno">8. </span>IANA considerations</a><ul class="toc"><li class="tocline"><a href="#text-vtt" class="tocxref"><span class="secno">8.1 </span><span><code>text/vtt</code></span></a></li></ul></li><li class="tocline"><a href="#references-1" class="tocxref"><span class="secno">9. </span>References</a></li><li class="tocline"><a href="#acknowledgements" class="tocxref"><span class="secno">10. </span>Acknowledgements</a></li></ul></section>
@@ -581,6 +585,23 @@
</div>
<div class="example">
+ <p>This example shows how to position cues at explicit positions in the video viewport.</p>
+
+ <pre>WEBVTT
+
+00:00:00.000 --> 00:00:04.000 position:10%,start align:start size:35%
+Where did he go?
+
+00:00:03.000 --> 00:00:06.500 position:90% align:end size:35%
+I think he went down this lane.
+
+00:00:04.000 --> 00:00:06.500 position:45%,end align:middle size:35%
+What are you waiting for?</pre>
+
+ <p>The cues cover only 35% of the video viewport's width. The first cue has its <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> left aligned at the 10% mark of the video viewport width and the text is left aligned within that box - probably underneath a speaker on the left of the video image. "start" alignment of the cue box is the default for start aligned text, so does not need to be specified in "position". The second cue has its <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> right aligned at the 90% mark of the video viewport width. The same effect can be achieved with "position:55%,start", which explicitly positions the cue box. The third cue has middle aligned text within the same type of cue box as the first cue.</p>
+ </div>
+
+ <div class="example">
<p>This example shows two regions containing rollup captions for two different speakers. Fred's cues scroll up in a region in the left half of the video, Bill's cues scroll up in a region on the right half of the video. Fred's first cue disappears at 12.5sec even through it is defined until 20sec because its region is limited to 3 lines and at 12.5sec a fourth cue appears:
</p>
@@ -719,6 +740,19 @@
<dl>
+ <dt><dfn title="text track cue box" id="dfn-text-track-cue-box">A cue box</dfn>
+ </dt><dd>
+ <p>The cue box of a <a href="#dfn-text-track-cue" class="internalDFN">text track cue</a> is a box within which the text of all lines of the
+ cue is to be rendered.</p>
+
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_1"><span>Note</span></div><p class="">The position of the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> within the video frame's dimensions depends
+ on the value of the <a href="#dfn-text-track-cue-text-position" class="internalDFN">text track cue text position</a> and the <a href="#dfn-text-track-cue-line-position" class="internalDFN">text track cue line position</a>.</p></div>
+
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_2"><span>Note</span></div><p class="">Lines are wrapped within the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>'s
+ <a title="text track cue size" href="#dfn-text-track-cue-size" class="internalDFN">size</a> if lines lengths make this necessary.</p></div>
+
+ </dd>
+
<dt><dfn title="text track cue writing direction" id="dfn-text-track-cue-writing-direction">A writing direction</dfn>
</dt><dd>
<p>A writing direction, either <dfn title="text track cue horizontal writing
@@ -730,7 +764,10 @@
growing right</dfn> (a line extends vertically and is positioned horizontally, with consecutive
lines displayed to the right of each other<!-- used for mongolian -->).</p>
- <p>If the <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a> is <a title="text track cue horizontal writing direction" href="#dfn-text-track-cue-horizontal-writing-direction" class="internalDFN">horizontal</a>, then <a title="text
+ <p>The writing direction is a property of the text inside the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> which
+ influences the interpretation of the positioning settings of the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>.</p>
+
+ <p>If the <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a> is <a title="text track cue horizontal writing direction" href="#dfn-text-track-cue-horizontal-writing-direction" class="internalDFN">horizontal</a>, then the <a title="text
track cue line position" href="#dfn-text-track-cue-line-position" class="internalDFN">line position</a> percentages are relative to the height of the
video, and <a title="text track cue text position" href="#dfn-text-track-cue-text-position" class="internalDFN">text position</a> and <a title="text
track cue size" href="#dfn-text-track-cue-size" class="internalDFN">size</a> percentages are relative to the width of the video.</p>
@@ -761,12 +798,15 @@
</dd>
- <dt><dfn title="text track cue line position" id="dfn-text-track-cue-line-position">A line position</dfn>
+ <dt><dfn title="text track cue line position" id="dfn-text-track-cue-line-position">A cue line position</dfn>
</dt><dd>
- <p>Either a number giving the position of the lines of the cue, to be interpreted as defined by
- the <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a> and <a title="text track cue snap-to-lines flag" href="#dfn-text-track-cue-snap-to-lines-flag" class="internalDFN">snap-to-lines flag</a> of the cue, or the special
+ <p>The line position defines positioning of the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>.</p>
+
+ <p>A line position is either a number giving the position of the lines of the cue, to be
+ interpreted as defined by the <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a>
+ and <a title="text track cue snap-to-lines flag" href="#dfn-text-track-cue-snap-to-lines-flag" class="internalDFN">snap-to-lines flag</a> of the cue, or the special
value <dfn title="text track cue automatic line position" id="dfn-text-track-cue-automatic-line-position">auto</dfn>, which means the position
- is to depend on the other active cues.</p>
+ is to depend on the other <a title="Text track cue active flag" href="#dfn-text-track-cue-active-flag" class="internalDFN">active</a> cues.</p>
<p>A <a href="#dfn-text-track-cue" class="internalDFN">text track cue</a> has a <dfn id="dfn-text-track-cue-computed-line-position">text track cue computed line position</dfn> whose
value is that returned by the following algorithm, which is defined in terms of the other
@@ -814,76 +854,162 @@
</dd>
+ <dt><dfn title="text track cue line alignment" id="dfn-text-track-cue-line-alignment">A cue line alignment</dfn>
+ </dt><dd>
+ <p>An alignment for the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>'s <a title="text track cue line position" href="#dfn-text-track-cue-line-position" class="internalDFN">line position</a>,
+ one of:</p>
+
+ <dl>
+
+ <dt><dfn title="text track cue line start alignment" id="dfn-text-track-cue-line-start-alignment">Start alignment</dfn></dt>
+ <dd>The <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>'s top side (for
+ <a title="text track cue horizontal writing direction" href="#dfn-text-track-cue-horizontal-writing-direction" class="internalDFN">horizontal</a> cues),
+ left side (for
+ <a title="text track cue vertical growing right writing direction" href="#dfn-text-track-cue-vertical-growing-right-writing-direction" class="internalDFN">vertical growing right</a>),
+ or right side (for
+ <a title="text track cue vertical growing left writing direction" href="#dfn-text-track-cue-vertical-growing-left-writing-direction" class="internalDFN">vertical growing left</a>)
+ is aligned at the <a title="text track cue line position" href="#dfn-text-track-cue-line-position" class="internalDFN">line position</a>.
+ </dd>
+
+ <dt><dfn title="text track cue line middle alignment" id="dfn-text-track-cue-line-middle-alignment">Middle alignment</dfn></dt>
+ <dd>The <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> is centered at the
+ <a title="text track cue line position" href="#dfn-text-track-cue-line-position" class="internalDFN">line position</a>.
+ </dd>
+
+ <dt><dfn title="text track cue line end alignment" id="dfn-text-track-cue-line-end-alignment">End alignment</dfn></dt>
+ <dd>The <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>'s bottom side (for
+ <a title="text track cue horizontal writing direction" href="#dfn-text-track-cue-horizontal-writing-direction" class="internalDFN">horizontal</a> cues),
+ right side (for
+ <a title="text track cue vertical growing right writing direction" href="#dfn-text-track-cue-vertical-growing-right-writing-direction" class="internalDFN">vertical growing right</a>),
+ or left side (for
+ <a title="text track cue vertical growing left writing direction" href="#dfn-text-track-cue-vertical-growing-left-writing-direction" class="internalDFN">vertical growing left</a>)
+ is aligned at the <a title="text track cue line position" href="#dfn-text-track-cue-line-position" class="internalDFN">line position</a>.
+ </dd>
+
+ </dl>
+
+ <p>A <a href="#dfn-text-track-cue" class="internalDFN">text track cue</a> has a default <a href="#dfn-text-track-cue-line-alignment" class="internalDFN">text track cue line alignment</a> of <a title="text track cue line start alignment" href="#dfn-text-track-cue-line-start-alignment" class="internalDFN">start</a>.</p>
+
+ </dd>
+
<dt><dfn title="text track cue size" id="dfn-text-track-cue-size">A size</dfn>
</dt><dd>
- <p>A number giving the size of the box within which the text of each line of the cue is to be
- rendered, to be interpreted as a percentage of the video, as defined by the <a title="text
- track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a>. This box is called the <dfn id="dfn-cue-box">cue box</dfn>.</p>
+ <p>A number giving the size of the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>, to be interpreted as a percentage of the video,
+ as defined by the <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a>.</p>
<p>By default, the <a href="#dfn-text-track-cue-size" class="internalDFN">text track cue size</a> is 100%.</p>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_1"><span>Note</span></div><p class="">The position of the <a href="#dfn-cue-box" class="internalDFN">cue box</a> within the video frame's dimensions depends
- on the value of the text track text position.</p></div>
-
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_2"><span>Note</span></div><p class="">Lines are wrapped within the <a href="#dfn-cue-box" class="internalDFN">cue box</a>'s
- <a title="text track cue size" href="#dfn-text-track-cue-size" class="internalDFN">size</a> if lines lengths make this necessary.</p></div>
</dd>
<dt><dfn title="text track cue text position" id="dfn-text-track-cue-text-position">A text position</dfn>
</dt><dd>
- <p>A number giving the position of the <a href="#dfn-cue-box" class="internalDFN">cue box</a> within each line. If the cue is not within
+ <p>A number giving the position of the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>. If the cue is not within
a region, the value is to be interpreted as a percentage of the video, as defined by the
<a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a>, otherwise to be interpreted
as a percentage of the region width.</p>
- <p>A <a href="#dfn-text-track-cue" class="internalDFN">text track cue</a> has a default <a href="#dfn-text-track-cue-text-position" class="internalDFN">text track cue text position</a> which is defined
- in terms of the value of the <a href="#dfn-text-track-cue-alignment" class="internalDFN">text track cue alignment</a>:</p>
+ <p>A <a href="#dfn-text-track-cue" class="internalDFN">text track cue</a> has a <df>default text track cue text position which is defined
+ in terms of the value of the <a href="#dfn-text-track-cue-text-alignment" class="internalDFN">text track cue text alignment</a>:</df></p>
<ol>
- <li>For <a title="text track cue left alignment" href="#dfn-text-track-cue-left-alignment" class="internalDFN">left aligned</a> cues: 0%.</li>
+ <li>For <a title="text track cue left alignment" href="#dfn-text-track-cue-left-alignment" class="internalDFN">left aligned</a> or
+ <a title="text track cue start alignment" href="#dfn-text-track-cue-start-alignment" class="internalDFN">start aligned</a> cues: 0%.</li>
<li>For <a title="text track cue middle alignment" href="#dfn-text-track-cue-middle-alignment" class="internalDFN">middle aligned</a> cues: 50%.</li>
- <li>For <a title="text track cue right alignment" href="#dfn-text-track-cue-right-alignment" class="internalDFN">right aligned</a> cues: 100%.</li>
-
- <li>For <a title="text track cue start alignment" href="#dfn-text-track-cue-start-alignment" class="internalDFN">start aligned</a> cues with left-to-right
- <i>paragraph direction</i> <a href="#refsBIDI">[BIDI]</a>: 0%, otherwise 100%.</li>
-
- <li>For <a title="text track cue end alignment" href="#dfn-text-track-cue-end-alignment" class="internalDFN">end aligned</a> cues with left-to-right
- <i>paragraph direction</i> <a href="#refsBIDI">[BIDI]</a>: 100%, otherwise 0%.</li>
+ <li>For <a title="text track cue right alignment" href="#dfn-text-track-cue-right-alignment" class="internalDFN">right aligned</a> or
+ <a title="text track cue end alignment" href="#dfn-text-track-cue-end-alignment" class="internalDFN">end aligned</a> cues: 100%.</li>
</ol>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_3"><span>Note</span></div><p class="">Since the default value of the <a href="#dfn-text-track-cue-text-position" class="internalDFN">text track cue text position</a> is
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_3"><span>Note</span></div><p class="">Since the default value of the <a href="#dfn-text-track-cue-text-alignment" class="internalDFN">text track cue text alignment</a> is
<a title="text track cue middle alignment" href="#dfn-text-track-cue-middle-alignment" class="internalDFN">middle</a>, if there is no
- <a href="#dfn-text-track-cue-alignment" class="internalDFN">text track cue alignment</a> setting for a cue, the <a href="#dfn-text-track-cue-text-position" class="internalDFN">text track cue text position</a>
+ <a href="#dfn-text-track-cue-text-alignment" class="internalDFN">text track cue text alignment</a> setting for a cue, the <a href="#dfn-text-track-cue-text-position" class="internalDFN">text track cue text position</a>
defaults to 50%.</p></div>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_4"><span>Note</span></div><p class="">If a <a href="#dfn-text-track-cue-size" class="internalDFN">text track cue size</a> setting is provided for a cue, and the cue is
- not middle aligned, and the <a href="#dfn-cue-box" class="internalDFN">cue box</a> has been defined as a template to be filled with either
- left-to-right or right-to-left <i>paragraph direction</i> text, it is recommended to provide an
- explicit <a title="text track cue text position" href="#dfn-text-track-cue-text-position" class="internalDFN">text position</a> setting, since otherwise the
- cue may unexpectedly flip to the other half of the video viewport.</p></div>
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_4"><span>Note</span></div><p class="">Even for <a title="text track cue horizontal writing direction" href="#dfn-text-track-cue-horizontal-writing-direction" class="internalDFN">horizontal</a>
+ cues with right-to-left <i>paragraph direction</i> text, the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>
+ is positioned from the left edge of the video frame. This allows defining a rendering space template
+ which can be filled with either left-to-right or right-to-left <i>paragraph direction</i> text. If you
+ define such a <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> template with
+ <a title="text track cue start alignment" href="#dfn-text-track-cue-start-alignment" class="internalDFN">start</a> or <a title="text track cue end alignment" href="#dfn-text-track-cue-end-alignment" class="internalDFN">end</a>
+ aligned text, make sure to control its <a title="text track cue size" href="#dfn-text-track-cue-size" class="internalDFN">size</a> unless you want
+ text to flip from one side of the video frame to the other.</p></div>
</dd>
+ <dt><dfn title="text track cue text position alignment" id="dfn-text-track-cue-text-position-alignment">A text position alignment</dfn>
+ </dt><dd>
+ <p>An alignment for the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> in the dimension of the
+ <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a>, describing which part of the
+ <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> is aligned to the <a title="text track cue text position" href="#dfn-text-track-cue-text-position" class="internalDFN">text position</a>,
+ one of:</p>
+
+ <dl>
+
+ <dt><dfn title="text track cue text position start alignment" id="dfn-text-track-cue-text-position-start-alignment">Start alignment</dfn></dt>
+ <dd>The <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>'s left side (for
+ <a title="text track cue horizontal writing direction" href="#dfn-text-track-cue-horizontal-writing-direction" class="internalDFN">horizontal</a> cues) or top
+ side (otherwise) is aligned at the <a title="text track cue text position" href="#dfn-text-track-cue-text-position" class="internalDFN">text position</a>.
+ </dd>
+
+ <dt><dfn title="text track cue text position middle alignment" id="dfn-text-track-cue-text-position-middle-alignment">Middle alignment</dfn></dt>
+ <dd>The <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a> is centered at the <a title="text track cue text position" href="#dfn-text-track-cue-text-position" class="internalDFN">text position</a>.
+ </dd>
+
+ <dt><dfn title="text track cue text position end alignment" id="dfn-text-track-cue-text-position-end-alignment">End alignment</dfn></dt>
+ <dd>The <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>'s right side (for
+ <a title="text track cue horizontal writing direction" href="#dfn-text-track-cue-horizontal-writing-direction" class="internalDFN">horizontal</a> cues) or bottom
+ side (otherwise) is aligned at the <a title="text track cue text position" href="#dfn-text-track-cue-text-position" class="internalDFN">text position</a>.
+ </dd>
+
+ </dl>
+
+ <p>A <a href="#dfn-text-track-cue" class="internalDFN">text track cue</a> has a <dfn id="dfn-default-text-track-cue-text-position-alignment">default text track cue text position alignment</dfn>
+ which is defined in terms of the value of the <a href="#dfn-text-track-cue-text-alignment" class="internalDFN">text track cue text alignment</a>:</p>
+
+ <ol>
+
+ <li>For <a title="text track cue left alignment" href="#dfn-text-track-cue-left-alignment" class="internalDFN">left</a> or
+ <a title="text track cue start alignment" href="#dfn-text-track-cue-start-alignment" class="internalDFN">start</a> aligned cues:
+ <a title="text track cue text position start alignment" href="#dfn-text-track-cue-text-position-start-alignment" class="internalDFN">start</a>.</li>
+
+ <li>For <a title="text track cue middle alignment" href="#dfn-text-track-cue-middle-alignment" class="internalDFN">middle</a> aligned cues:
+ <a title="text track cue text position middle alignment" href="#dfn-text-track-cue-text-position-middle-alignment" class="internalDFN">middle</a>.</li>
+
+ <li>For <a title="text track cue right alignment" href="#dfn-text-track-cue-right-alignment" class="internalDFN">right</a> or
+ <a title="text track cue end alignment" href="#dfn-text-track-cue-end-alignment" class="internalDFN">end</a> aligned cues:
+ <a title="text track cue text position end alignment" href="#dfn-text-track-cue-text-position-end-alignment" class="internalDFN">end</a>.</li>
- <dt><dfn title="text track cue alignment" id="dfn-text-track-cue-alignment">An alignment</dfn>
+ </ol>
+
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_5"><span>Note</span></div><p class="">Since the <a href="#dfn-text-track-cue-text-position" class="internalDFN">text track cue text position</a> always measures from the left
+ of the video (for <a title="text track cue horizontal writing direction" href="#dfn-text-track-cue-horizontal-writing-direction" class="internalDFN">horizontal</a> cues)
+ or the top (otherwise), the <a href="#dfn-text-track-cue-text-position-alignment" class="internalDFN">text track cue text position alignment</a>
+ <a title="text track cue text position start alignment" href="#dfn-text-track-cue-text-position-start-alignment" class="internalDFN">start value</a> varies between left and
+ top for horizontal and vertical cues, but not between left and right even for changing
+ <i>paragraph direction</i>.</p></div>
+
+ </dd>
+
+ <dt><dfn title="text track cue text alignment" id="dfn-text-track-cue-text-alignment">A text alignment</dfn>
</dt><dd>
- <p>An alignment for all lines of text within the <a href="#dfn-cue-box" class="internalDFN">cue box</a>, one of:</p>
+ <p>An alignment for all lines of text within the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>, in the dimension of the
+ <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a> and the
+ <i>paragraph direction</i> <a href="#refsBIDI">[BIDI]</a>, one of:</p>
<dl>
<dt><dfn title="text track cue start alignment" id="dfn-text-track-cue-start-alignment">Start alignment</dfn></dt>
- <dd>The text is aligned towards the box's start side.</dd>
+ <dd>The text is aligned towards the <i>paragraph direction</i> start side of the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>.</dd>
<dt><dfn title="text track cue middle alignment" id="dfn-text-track-cue-middle-alignment">Middle alignment</dfn></dt>
<dd>The text is aligned centered between the box's start and end sides.</dd>
<dt><dfn title="text track cue end alignment" id="dfn-text-track-cue-end-alignment">End alignment</dfn></dt>
- <dd>The text is aligned towards the box's end side.</dd>
+ <dd>The text is aligned towards the <i>paragraph direction</i> end side of the <a title="text track cue box" href="#dfn-text-track-cue-box" class="internalDFN">cue box</a>.</dd>
<dt><dfn title="text track cue left alignment" id="dfn-text-track-cue-left-alignment">Left alignment</dfn></dt>
<dd>The text is aligned to the box's left side.</dd>
@@ -893,10 +1019,7 @@
</dl>
- <p>Which sides are the start and end sides depends on the Unicode bidirectional algorithm and
- the <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing direction</a>. <a href="#refsBIDI">[BIDI]</a></p>
-
- <p>By default, the value of the <a href="#dfn-text-track-cue-alignment" class="internalDFN">text track cue alignment</a> is
+ <p>By default, the value of the <a href="#dfn-text-track-cue-text-alignment" class="internalDFN">text track cue text alignment</a> is
<a title="text track cue middle alignment" href="#dfn-text-track-cue-middle-alignment" class="internalDFN">middle aligned</a>.</p>
</dd>
@@ -917,7 +1040,7 @@
flag</a> is set has its <a title="text track cue writing direction" href="#dfn-text-track-cue-writing-direction" class="internalDFN">writing
direction</a>, <a title="text track cue snap-to-lines flag" href="#dfn-text-track-cue-snap-to-lines-flag" class="internalDFN">snap-to-lines flag</a>, <a title="text track cue line position" href="#dfn-text-track-cue-line-position" class="internalDFN">line position</a>, <a title="text track cue text
position" href="#dfn-text-track-cue-text-position" class="internalDFN">text position</a>, <a title="text track cue size" href="#dfn-text-track-cue-size" class="internalDFN">size</a>, <a title="text
- track cue alignment" href="#dfn-text-track-cue-alignment" class="internalDFN">alignment</a>, <a title="text track region identifier" href="#dfn-text-track-region-identifier" class="internalDFN">region identifier</a>,
+ track cue text alignment" href="#dfn-text-track-cue-text-alignment" class="internalDFN">alignment</a>, <a title="text track region identifier" href="#dfn-text-track-region-identifier" class="internalDFN">region identifier</a>,
or <a title="text track cue text" href="#dfn-text-track-cue-text" class="internalDFN">text</a> change value, then the user agent must empty
the <a href="#dfn-text-track-cue-display-state" class="internalDFN">text track cue display state</a>, and then immediately run the <a href="#dfn-text-track" class="internalDFN">text track</a>'s
<a href="#dfn-rules-for-updating-the-display-of-webvtt-text-tracks" class="internalDFN">rules for updating the display of WebVTT text tracks</a>.</p>
@@ -1070,7 +1193,7 @@
<li>A <a href="#dfn-webvtt-line-terminator" class="internalDFN">WebVTT line terminator</a>.</li>
</ol>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_5"><span>Note</span></div><p class="">A <a href="#dfn-webvtt-cue" class="internalDFN">WebVTT cue</a> corresponds to one piece
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_6"><span>Note</span></div><p class="">A <a href="#dfn-webvtt-cue" class="internalDFN">WebVTT cue</a> corresponds to one piece
of time-aligned text or data in the <a href="#dfn-webvtt-file" class="internalDFN">WebVTT file</a>, for
example one subtitle. The <a href="#dfn-cue-payload" class="internalDFN">cue payload</a> is the text or
data associated with the cue.</p></div>
@@ -1081,7 +1204,7 @@
SIGN), nor containing any U+000A LINE FEED (LF) characters or U+000D
CARRIAGE RETURN (CR) characters.</p>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_6"><span>Note</span></div><p class="">A <a href="#dfn-webvtt-cue-identifier" class="internalDFN">WebVTT cue identifier</a> can be used to
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_7"><span>Note</span></div><p class="">A <a href="#dfn-webvtt-cue-identifier" class="internalDFN">WebVTT cue identifier</a> can be used to
reference a specific cue, for example from script or CSS.</p></div>
<p>The <dfn id="dfn-webvtt-cue-timings">WebVTT cue timings</dfn> part of a <a href="#dfn-webvtt-cue" class="internalDFN">WebVTT
@@ -1115,7 +1238,7 @@
</ol>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_7"><span>Note</span></div><p class="">The <a href="#dfn-webvtt-cue-timings" class="internalDFN">WebVTT cue timings</a> give the start
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_8"><span>Note</span></div><p class="">The <a href="#dfn-webvtt-cue-timings" class="internalDFN">WebVTT cue timings</a> give the start
and end offsets of the <a href="#dfn-webvtt-cue" class="internalDFN">WebVTT cue</a>. Different cues can
overlap. Cues are always listed ordered by their start time.</p></div>
@@ -1125,7 +1248,7 @@
<a title="partial WebVTT timestamp" href="#dfn-partial-webvtt-timestamp" class="internalDFN">WebVTT timestamp representing
a time in seconds and fractions of a second</a>.</p>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_8"><span>Note</span></div><p class="">A <a href="#dfn-webvtt-timestamp" class="internalDFN">WebVTT timestamp</a> is always interpreted
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_9"><span>Note</span></div><p class="">A <a href="#dfn-webvtt-timestamp" class="internalDFN">WebVTT timestamp</a> is always interpreted
relative to the <a href="#dfn-current-playback-position" class="internalDFN">current playback position</a> of the media data
that the WebVTT file is to be synchronised with, which always starts
at 0.</p></div>
@@ -1229,7 +1352,7 @@
<li>A <a href="#dfn-webvtt-line-terminator" class="internalDFN">WebVTT line terminator</a>.</li>
</ol>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_9"><span>Note</span></div><p class="">A <a href="#dfn-webvtt-comment" class="internalDFN">WebVTT comment</a> is ignored by the parser.</p></div>
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_10"><span>Note</span></div><p class="">A <a href="#dfn-webvtt-comment" class="internalDFN">WebVTT comment</a> is ignored by the parser.</p></div>
</section><!-- end comments -->
@@ -1504,7 +1627,7 @@
<li>A <a href="#dfn-webvtt-region-scroll-setting" class="internalDFN">WebVTT region scroll setting</a>.</li> <!-- scroll:up -->
</ul>
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_10"><span>Note</span></div><p class="">The <a href="#dfn-webvtt-region-setting-list" class="internalDFN">WebVTT region setting list</a> gives configuration
+ <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_11"><span>Note</span></div><p class="">The <a href="#dfn-webvtt-region-setting-list" class="internalDFN">WebVTT region setting list</a> gives configuration
options regarding the dimensions, positioning and anchoring of the region. For
example, it allows a group of cues within a region to be anchored in the center of the
region and the center of the video viewport. In this example, when the font size grows,
@@ -1520,7 +1643,7 @@
"<code>--></code>" (U+002D HYPHEN-MINUS, U+002D HYPHEN-MINUS,
U+003E GREATER-THAN SIGN).</p></li>
</ol>
- <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_11"><span>Note</span></div><p class="">The <a href="#dfn-webvtt-region-identifier" class="internalDFN">WebVTT region identifier</a> gives
+ <div class="note"><div class="note-title" aria-level="4" role="heading" id="h_note_12"><span>Note</span></div><p class="">The <a href="#dfn-webvtt-region-identifier" class="internalDFN">WebVTT region identifier</a> gives
a name to the region so it can be referenced by the cues that belong to the region.</p></div>
<p>A <dfn id="dfn-webvtt-region-width-setting">WebVTT region width setting</dfn> consists of the
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Received on Thursday, 14 November 2013 14:09:08 UTC