W3C home > Mailing lists > Public > public-html-commits@w3.org > June 2011

html5/spec Overview.html,1.5022,1.5023

From: Ian Hickson via cvs-syncmail <cvsmail@w3.org>
Date: Thu, 30 Jun 2011 23:52:54 +0000
To: public-html-commits@w3.org
Message-Id: <E1QcR2U-0003qK-Te@lionel-hutz.w3.org>
Update of /sources/public/html5/spec
In directory hutz:/tmp/cvs-serv14734

Modified Files:
	Overview.html 
Log Message:
Revamp how audioTracks and videoTracks work on HTMLMediaElement and MediaStream. (whatwg r6275)

Index: Overview.html
===================================================================
RCS file: /sources/public/html5/spec/Overview.html,v
retrieving revision 1.5022
retrieving revision 1.5023
diff -u -d -r1.5022 -r1.5023
--- Overview.html	24 Jun 2011 00:32:45 -0000	1.5022
+++ Overview.html	30 Jun 2011 23:52:50 -0000	1.5023
@@ -318,7 +318,7 @@
 
    <h1>HTML5</h1>
    <h2 class="no-num no-toc" id="a-vocabulary-and-associated-apis-for-html-and-xhtml">A vocabulary and associated APIs for HTML and XHTML</h2>
-   <h2 class="no-num no-toc" id="editor-s-draft-24-june-2011">Editor's Draft 24 June 2011</h2>
+   <h2 class="no-num no-toc" id="editor-s-draft-30-june-2011">Editor's Draft 30 June 2011</h2>
    <dl><dt>Latest Published Version:</dt>
     <dd><a href="http://www.w3.org/TR/html5/">http://www.w3.org/TR/html5/</a></dd>
     <dt>Latest Editor's Draft:</dt>
@@ -464,7 +464,7 @@
   Group</a> is the W3C working group responsible for this
   specification's progress along the W3C Recommendation
   track.
-  This specification is the 24 June 2011 Editor's Draft.
+  This specification is the 30 June 2011 Editor's Draft.
   </p><!-- UNDER NO CIRCUMSTANCES IS THE PRECEDING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST --><p>Work on this specification is also done at the <a href="http://www.whatwg.org/">WHATWG</a>. The W3C HTML working group
   actively pursues convergence with the WHATWG, as required by the <a href="http://www.w3.org/2007/03/HTML-WG-charter">W3C HTML working
   group charter</a>.</p><!-- UNDER NO CIRCUMSTANCES IS THE FOLLOWING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST --><p>This document was produced by a group operating under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5
@@ -767,7 +767,7 @@
        <li><a href="#seeking"><span class="secno">4.8.10.9 </span>Seeking</a></li>
        <li><a href="#media-resources-with-multiple-media-tracks"><span class="secno">4.8.10.10 </span>Media resources with multiple media tracks</a>
         <ol>
-         <li><a href="#tracklist-objects"><span class="secno">4.8.10.10.1 </span><code>TrackList</code> objects</a></li>
+         <li><a href="#audiotracklist-and-videotracklist-objects"><span class="secno">4.8.10.10.1 </span><code>AudioTrackList</code> and <code>VideoTrackList</code> objects</a></li>
          <li><a href="#selecting-specific-audio-and-video-tracks-declaratively"><span class="secno">4.8.10.10.2 </span>Selecting specific audio and video tracks declaratively</a></ol></li>
        <li><a href="#synchronising-multiple-media-elements"><span class="secno">4.8.10.11 </span>Synchronising multiple media elements</a>
         <ol>
@@ -2941,9 +2941,9 @@
     specification. <a href="#refsWEBIDL">[WEBIDL]</a></p>
 
     <p>The terms <dfn id="supported-property-indices">supported property indices</dfn>, <dfn id="supported-property-names">supported
-    property names</dfn>, and <dfn id="dfn-read-only-array" title="dfn-read-only-array">read
-    only</dfn> (when applied to arrays) are used as defined in the
-    WebIDL specification.</p>
+    property names</dfn>, <dfn id="determine-the-value-of-an-indexed-property">determine the value of an indexed
+    property</dfn>, <dfn id="array-host-objects">array host objects</dfn>, and <dfn id="dfn-read-only-array" title="dfn-read-only-array">read only</dfn> (when applied to
+    arrays) are used as defined in the WebIDL specification.</p>
 
     <p id="float-nan">Except where otherwise specified, if an IDL
     attribute that is a floating point number type (<code title="">double</code>) is assigned an Infinity or Not-a-Number
@@ -22294,9 +22294,9 @@
            attribute boolean <a href="#dom-media-defaultmuted" title="dom-media-defaultMuted">defaultMuted</a>;
 
   // tracks
-  readonly attribute <a href="#multipletracklist">MultipleTrackList</a> <a href="#dom-media-audiotracks" title="dom-media-audioTracks">audioTracks</a>;
-  readonly attribute <a href="#exclusivetracklist">ExclusiveTrackList</a> <a href="#dom-media-videotracks" title="dom-media-videoTracks">videoTracks</a>;
-  readonly attribute <a href="#texttrack">TextTrack</a>[] <a href="#dom-media-texttracks" title="dom-media-textTracks">textTracks</a>;
+  readonly attribute <a href="#audiotracklist">AudioTrackList</a> <a href="#dom-media-audiotracks" title="dom-media-audioTracks">audioTracks</a>;
+  readonly attribute <a href="#videotracklist">VideoTrackList</a> <a href="#dom-media-videotracks" title="dom-media-videoTracks">videoTracks</a>;
+  readonly attribute <a href="#texttracklist">TextTrackList</a> <a href="#dom-media-texttracks" title="dom-media-textTracks">textTracks</a>;
   <a href="#mutabletexttrack">MutableTextTrack</a> <a href="#dom-media-addtexttrack" title="dom-media-addTextTrack">addTextTrack</a>(in DOMString kind, in optional DOMString label, in optional DOMString language);
 };</pre><p>The <dfn id="media-element-attributes">media element attributes</dfn>, <code title="attr-media-src"><a href="#attr-media-src">src</a></code>, <code title="attr-media-crossorigin"><a href="#attr-media-crossorigin">crossorigin</a></code>, <code title="attr-media-preload"><a href="#attr-media-preload">preload</a></code>, <code title="attr-media-autoplay"><a href="#attr-media-autoplay">autoplay</a></code>, 
   <code title="attr-media-mediagroup"><a href="#attr-media-mediagroup">mediagroup</a></code>, 
@@ -24642,7 +24642,7 @@
 
    <dd>
 
-    <p>Returns a <code><a href="#multipletracklist">MultipleTrackList</a></code> object representing
+    <p>Returns an <code><a href="#audiotracklist">AudioTrackList</a></code> object representing
     the audio tracks available in the <a href="#media-resource">media resource</a>.</p>
 
    </dd>
@@ -24651,7 +24651,7 @@
 
    <dd>
 
-    <p>Returns an <code><a href="#exclusivetracklist">ExclusiveTrackList</a></code> object representing
+    <p>Returns an <code><a href="#videotracklist">VideoTrackList</a></code> object representing
     the video tracks available in the <a href="#media-resource">media resource</a>.</p>
 
    </dd>
@@ -24660,23 +24660,24 @@
 
   <p>The <dfn id="dom-media-audiotracks" title="dom-media-audioTracks"><code>audioTracks</code></dfn>
   attribute of a <a href="#media-element">media element</a> must return a
-  <a href="#live">live</a> <code><a href="#multipletracklist">MultipleTrackList</a></code> object representing
+  <a href="#live">live</a> <code><a href="#audiotracklist">AudioTrackList</a></code> object representing
   the audio tracks available in the <a href="#media-element">media element</a>'s
   <a href="#media-resource">media resource</a>. The same object must be returned each
   time.</p>
 
   <p>The <dfn id="dom-media-videotracks" title="dom-media-videoTracks"><code>videoTracks</code></dfn>
   attribute of a <a href="#media-element">media element</a> must return a
-  <a href="#live">live</a> <code><a href="#exclusivetracklist">ExclusiveTrackList</a></code> object
+  <a href="#live">live</a> <code><a href="#videotracklist">VideoTrackList</a></code> object
   representing the video tracks available in the <a href="#media-element">media
   element</a>'s <a href="#media-resource">media resource</a>. The same object must
   be returned each time.</p>
 
-  <p class="note">There are only ever two <code><a href="#tracklist">TrackList</a></code>
-  objects (one <code><a href="#multipletracklist">MultipleTrackList</a></code> object and one
-  <code><a href="#exclusivetracklist">ExclusiveTrackList</a></code> object) per <a href="#media-element">media
+  <p class="note">There are only ever one <code><a href="#audiotracklist">AudioTrackList</a></code>
+  object and one <code><a href="#videotracklist">VideoTrackList</a></code> object per <a href="#media-element">media
   element</a>, even if another <a href="#media-resource">media resource</a> is
-  loaded into the element: the objects are reused.</p>
+  loaded into the element: the objects are reused. (The
+  <code><a href="#audiotrack">AudioTrack</a></code> and <code><a href="#videotrack">VideoTrack</a></code> objects are
+  not, though.)</p>
 
   </div><div class="example">
 
@@ -24699,9 +24700,9 @@
    container.appendChild(video);
    video.onloadedmetadata = function (event) {
      for (var i = 0; i &lt; video.videoTracks.length; i += 1) {
-       if (video.videoTracks.getKind(i) == 'sign') {
+       if (video.videoTracks[i].kind == 'sign') {
          var sign = document.createElement('video');
-         sign.src = url + '#track=' + video.videoTracks.getID(i);
+         sign.src = url + '#track=' + video.videoTracks[i].id; 
          sign.autoplay = true;
          sign.controller = controller;
          container.appendChild(sign);
@@ -24712,30 +24713,39 @@
  }
 &lt;/script&gt;</pre>
 
-  </div><h6 id="tracklist-objects"><span class="secno">4.8.10.10.1 </span><code><a href="#tracklist">TrackList</a></code> objects</h6><p>The <code><a href="#multipletracklist">MultipleTrackList</a></code> and
-  <code><a href="#exclusivetracklist">ExclusiveTrackList</a></code> interfaces, used by the attributes
-  defined in the previous section, are substantially similar. Their
-  common features are defined in the <code><a href="#tracklist">TrackList</a></code> interface,
-  from which they both inherit.</p><pre class="idl">interface <dfn id="tracklist">TrackList</dfn> {
-  readonly attribute unsigned long <a href="#dom-tracklist-length" title="dom-TrackList-length">length</a>;
-  DOMString <a href="#dom-tracklist-getid" title="dom-TrackList-getID">getID</a>(in unsigned long index);
-  DOMString <a href="#dom-tracklist-getkind" title="dom-TrackList-getKind">getKind</a>(in unsigned long index);
-  DOMString <a href="#dom-tracklist-getlabel" title="dom-TrackList-getLabel">getLabel</a>(in unsigned long index);
-  DOMString <a href="#dom-tracklist-getlanguage" title="dom-TrackList-getLanguage">getLanguage</a>(in unsigned long index);
-
+  </div><h6 id="audiotracklist-and-videotracklist-objects"><span class="secno">4.8.10.10.1 </span><code><a href="#audiotracklist">AudioTrackList</a></code> and <code><a href="#videotracklist">VideoTrackList</a></code> objects</h6><p>The <code><a href="#audiotracklist">AudioTrackList</a></code> and <code><a href="#videotracklist">VideoTrackList</a></code>
+  interfaces are used by attributes defined in the previous
+  section.<pre class="idl">interface <dfn id="audiotracklist">AudioTrackList</dfn> {
+  readonly attribute unsigned long <a href="#dom-audiotracklist-length" title="dom-AudioTrackList-length">length</a>;
+  getter <a href="#audiotrack">AudioTrack</a> (in unsigned long index);
+  <a href="#audiotrack">AudioTrack</a>? <a href="#dom-audiotracklist-gettrackbyid" title="dom-AudioTrackList-getTrackById">getTrackById</a>(in DOMString id);
            attribute <a href="#function">Function</a>? <a href="#handler-tracklist-onchange" title="handler-TrackList-onchange">onchange</a>;
 };
 
-interface <dfn id="multipletracklist">MultipleTrackList</dfn> : <a href="#tracklist">TrackList</a> {
-  boolean <a href="#dom-tracklist-isenabled" title="dom-TrackList-isEnabled">isEnabled</a>(in unsigned long index);
-  void <a href="#dom-tracklist-enable" title="dom-TrackList-enable">enable</a>(in unsigned long index);
-  void <a href="#dom-tracklist-disable" title="dom-TrackList-disable">disable</a>(in unsigned long index);
+interface <dfn id="audiotrack">AudioTrack</dfn> {
+  readonly attribute DOMString <a href="#dom-audiotrack-id" title="dom-AudioTrack-id">id</a>;
+  readonly attribute DOMString <a href="#dom-audiotrack-kind" title="dom-AudioTrack-kind">kind</a>;
+  readonly attribute DOMString <a href="#dom-audiotrack-label" title="dom-AudioTrack-label">label</a>;
+  readonly attribute DOMString <a href="#dom-audiotrack-language" title="dom-AudioTrack-language">language</a>;
+           attribute boolean <a href="#dom-audiotrack-enabled" title="dom-AudioTrack-enabled">enabled</a>;
 };
 
-interface <dfn id="exclusivetracklist">ExclusiveTrackList</dfn> : <a href="#tracklist">TrackList</a> {
-  readonly attribute long <a href="#dom-tracklist-selectedindex" title="dom-TrackList-selectedIndex">selectedIndex</a>;
-  void <a href="#dom-tracklist-select" title="dom-TrackList-select">select</a>(in unsigned long index);
-};</pre><dl class="domintro"><dt><var title="">tracks</var> . <code title="dom-TrackList-length"><a href="#dom-tracklist-length">length</a></code></dt>
+interface <dfn id="videotracklist">VideoTrackList</dfn> {
+  readonly attribute unsigned long <a href="#dom-videotracklist-length" title="dom-VideoTrackList-length">length</a>;
+  getter <a href="#videotrack">VideoTrack</a> (in unsigned long index);
+  <a href="#videotrack">VideoTrack</a>? <a href="#dom-videotracklist-gettrackbyid" title="dom-VideoTrackList-getTrackById">getTrackById</a>(in DOMString id);
+  readonly attribute long <a href="#dom-videotracklist-selectedindex" title="dom-VideoTrackList-selectedIndex">selectedIndex</a>;
+           attribute <a href="#function">Function</a>? <a href="#handler-tracklist-onchange" title="handler-TrackList-onchange">onchange</a>;
+};
+
+interface <dfn id="videotrack">VideoTrack</dfn> {
+  readonly attribute DOMString <a href="#dom-videotrack-id" title="dom-VideoTrack-id">id</a>;
+  readonly attribute DOMString <a href="#dom-videotrack-kind" title="dom-VideoTrack-kind">kind</a>;
+  readonly attribute DOMString <a href="#dom-videotrack-label" title="dom-VideoTrack-label">label</a>;
+  readonly attribute DOMString <a href="#dom-videotrack-language" title="dom-VideoTrack-language">language</a>;
+           attribute boolean <a href="#dom-videotrack-selected" title="dom-VideoTrack-selected">selected</a>;
+};</pre><dl class="domintro"><dt><var title="">media</var> . <code title="dom-media-audioTracks"><a href="#dom-media-audiotracks">audioTracks</a></code> . <code title="dom-AudioTrackList-length"><a href="#dom-audiotracklist-length">length</a></code></dt>
+   <dt><var title="">media</var> . <code title="dom-media-videoTracks"><a href="#dom-media-videotracks">videoTracks</a></code> . <code title="dom-VideoTrackList-length"><a href="#dom-videotracklist-length">length</a></code></dt>
 
    <dd>
 
@@ -24743,65 +24753,74 @@
 
    </dd>
 
-   <dt><var title="">id</var> = <var title="">tracks</var> . <code title="dom-TrackList-getID"><a href="#dom-tracklist-getid">getID</a></code>( <var title="">index</var> )</dt>
+   <dt><var title="">audioTrack</var> = <var title="">media</var> . <code title="dom-media-audioTracks"><a href="#dom-media-audiotracks">audioTracks</a></code>[<var title="">index</var>]</dt>
+   <dt><var title="">videoTrack</var> = <var title="">media</var> . <code title="dom-media-videoTracks"><a href="#dom-media-videotracks">videoTracks</a></code>[<var title="">index</var>]</dt>
 
    <dd>
 
-    <p>Returns the ID of the given track. This is the ID that can be
-    used with a fragment identifier if the format supports the
-    <cite>Media Fragments URI</cite> syntax. <a href="#hrefMEDIAFRAG">[MEDIAFRAG]</a></p>
+    <p>Returns the specified <code><a href="#audiotrack">AudioTrack</a></code> or <code><a href="#videotrack">VideoTrack</a></code> object.</p>
 
    </dd>
 
-   <dt><var title="">kind</var> = <var title="">tracks</var> . <code title="dom-TrackList-getKind"><a href="#dom-tracklist-getkind">getKind</a></code>( <var title="">index</var> )</dt>
+   <dt><var title="">audioTrack</var> = <var title="">media</var> . <code title="dom-media-audioTracks"><a href="#dom-media-audiotracks">audioTracks</a></code> . <code title="dom-AudioTrackList-getTrackById"><a href="#dom-audiotracklist-gettrackbyid">getTrackById</a></code>( <var title="">id</var> )</dt>
+   <dt><var title="">videoTrack</var> = <var title="">media</var> . <code title="dom-media-videoTracks"><a href="#dom-media-videotracks">videoTracks</a></code> . <code title="dom-VideoTrackList-getTrackById"><a href="#dom-videotracklist-gettrackbyid">getTrackById</a></code>( <var title="">id</var> )</dt>
 
    <dd>
 
-    <p>Returns the category the given track falls into. The <a href="#dom-TrackList-getKind-categories">possible track categories</a> are given below.</p>
+    <p>Returns the <code><a href="#audiotrack">AudioTrack</a></code> or <code><a href="#videotrack">VideoTrack</a></code> object with the given identifier, or null if no track has that identifier.</p>
 
    </dd>
 
-   <dt><var title="">label</var> = <var title="">tracks</var> . <code title="dom-TrackList-getLabel"><a href="#dom-tracklist-getlabel">getLabel</a></code>( <var title="">index</var> )</dt>
+   <dt><var title="">audioTrack</var> . <code title="dom-AudioTrack-id"><a href="#dom-audiotrack-id">id</a></code></dt>
+   <dt><var title="">videoTrack</var> . <code title="dom-VideoTrack-id"><a href="#dom-videotrack-id">id</a></code></dt>
 
    <dd>
 
-    <p>Returns the label of the given track, if known, or the empty string otherwise.</p>
+    <p>Returns the ID of the given track. This is the ID that can be
+    used with a fragment identifier if the format supports the
+    <cite>Media Fragments URI</cite> syntax, and that can be used with
+    the <code title="">getTrackById()</code> method. <a href="#hrefMEDIAFRAG">[MEDIAFRAG]</a></p>
 
    </dd>
 
-   <dt><var title="">language</var> = <var title="">tracks</var> . <code title="dom-TrackList-getLanguage"><a href="#dom-tracklist-getlanguage">getLanguage</a></code>( <var title="">index</var> )</dt>
+   <dt><var title="">audioTrack</var> . <code title="dom-AudioTrack-kind"><a href="#dom-audiotrack-kind">kind</a></code></dt>
+   <dt><var title="">videoTrack</var> . <code title="dom-VideoTrack-kind"><a href="#dom-videotrack-kind">kind</a></code></dt>
 
    <dd>
 
-    <p>Returns the language of the given track, if known, or the empty string otherwise.</p>
+    <p>Returns the category the given track falls into. The <a href="#dom-TrackList-getKind-categories">possible track categories</a> are given below.</p>
 
    </dd>
 
-   <dt><var title="">enabled</var> = <var title="">audioTracks</var> . <code title="dom-TrackList-isEnabled"><a href="#dom-tracklist-isenabled">isEnabled</a></code>( <var title="">index</var> )</dt>
+   <dt><var title="">audioTrack</var> . <code title="dom-AudioTrack-label"><a href="#dom-audiotrack-label">label</a></code></dt>
+   <dt><var title="">videoTrack</var> . <code title="dom-VideoTrack-label"><a href="#dom-videotrack-label">label</a></code></dt>
 
    <dd>
 
-    <p>Returns true if the given track is active, and false otherwise.</p>
+    <p>Returns the label of the given track, if known, or the empty string otherwise.</p>
 
    </dd>
 
-   <dt><var title="">audioTracks</var> . <code title="dom-TrackList-enable"><a href="#dom-tracklist-enable">enable</a></code>( <var title="">index</var> )</dt>
+   <dt><var title="">audioTrack</var> . <code title="dom-AudioTrack-language"><a href="#dom-audiotrack-language">language</a></code></dt>
+   <dt><var title="">videoTrack</var> . <code title="dom-VideoTrack-language"><a href="#dom-videotrack-language">language</a></code></dt>
 
    <dd>
 
-    <p>Enables the given track.</p>
+    <p>Returns the language of the given track, if known, or the empty string otherwise.</p>
 
    </dd>
 
-   <dt><var title="">audioTracks</var> . <code title="dom-TrackList-disable"><a href="#dom-tracklist-disable">disable</a></code>( <var title="">index</var> )</dt>
+   <dt><var title="">audioTrack</var> . <code title="dom-AudioTrack-enabled"><a href="#dom-audiotrack-enabled">enabled</a></code> [ = <var title="">value</var> ]</dt>
 
    <dd>
 
-    <p>Disables the given track.</p>
+    <p>Returns true if the given track is active, and false otherwise.</p>
+
+    <p>Can be set, to change whether the track is enabled or not. If multiple audio tracks are enabled simultaneously, they are mixed.</p>
 
    </dd>
 
-   <dt><var title="">videoTracks</var> . <code title="dom-TrackList-selectedIndex"><a href="#dom-tracklist-selectedindex">selectedIndex</a></code></dt>
+   <dt><var title="">media</var> . <code title="dom-media-videoTracks"><a href="#dom-media-videotracks">videoTracks</a></code> . <code title="dom-VideoTrackList-selectedIndex"><a href="#dom-videotracklist-selectedindex">selectedIndex</a></code></dt>
 
    <dd>
 
@@ -24809,42 +24828,106 @@
 
    </dd>
 
-   <dt><var title="">videoTracks</var> . <code title="dom-TrackList-select"><a href="#dom-tracklist-select">select</a></code>( <var title="">index</var> )</dt>
+   <dt><var title="">videoTrack</var> . <code title="dom-VideoTrack-selected"><a href="#dom-videotrack-selected">selected</a></code> [ = <var title="">value</var> ]</dt>
 
    <dd>
 
-    <p>Selects the given track.</p>
+    <p>Returns true if the given track is active, and false otherwise.</p>
+
+    <p>Can be set, to change whether the track is selected or not. Either zero or one video track is selected; selecting a new track while a previous one is selected will unselect the previous one.</p>
 
    </dd>
 
   </dl><div class="impl">
 
-  <p>The <dfn id="dom-tracklist-length" title="dom-TrackList-length"><code>length</code></dfn>
-  attribute must return the number of tracks represented by the
-  <code><a href="#tracklist">TrackList</a></code> object at the time of getting.</p>
+  <p>An <code><a href="#audiotracklist">AudioTrackList</a></code> object represents a dynamic list
+  of zero or more audio tracks, of which zero or more can be enabled
+  at a time. Each audio track is represented by an
+  <code><a href="#audiotrack">AudioTrack</a></code> object.</p>
 
-  <p>Tracks in a <code><a href="#tracklist">TrackList</a></code> object must be consistently
-  ordered. If the <a href="#media-resource">media resource</a> is in a format that
-  defines an order, then that order must be used; otherwise, the order
-  must be the relative order in which the tracks are declared in the
-  <a href="#media-resource">media resource</a>. Each track in a <code><a href="#tracklist">TrackList</a></code>
-  thus has an index; the first has the index 0, and each subsequent
-  track is numbered one higher than the previous one.</p>
+  <p>A <code><a href="#videotracklist">VideoTrackList</a></code> object represents a dynamic list of
+  zero or more video tracks, of which zero or one can be selected at a
+  time. Each video track is represented by a <code><a href="#videotrack">VideoTrack</a></code>
+  object.</p>
 
-  <p>The <dfn id="dom-tracklist-getid" title="dom-TrackList-getID"><code>getID(<var title="">index</var>)</code></dfn> method must return the identifier
-  of the track with index <var title="">index</var>, if there is one.
-  If there is no such track, then the method must instead throw an
-  <code><a href="#index_size_err">INDEX_SIZE_ERR</a></code> exception. If the <a href="#media-resource">media
-  resource</a> is in a format that supports the <cite>Media
-  Fragments URI</cite> fragment identifier syntax, the returned
-  identifier must be the same identifier that would enable the track
-  if used as the name of a track in the track dimension of such a
+  <p>Tracks in <code><a href="#audiotracklist">AudioTrackList</a></code> and
+  <code><a href="#videotracklist">VideoTrackList</a></code> objects must be consistently ordered. If
+  the <a href="#media-resource">media resource</a> is in a format that defines an
+  order, then that order must be used; otherwise, the order must be
+  the relative order in which the tracks are declared in the
+  <a href="#media-resource">media resource</a>. The order used is called the <i>natural
+  order</i> of the list.</p>
+
+  <p class="note">Each track in a <code>TrackList</code> thus has an
+  index; the first has the index 0, and each subsequent track is
+  numbered one higher than the previous one. If a <a href="#media-resource">media
+  resource</a> dynamically adds or removes audio or video tracks,
+  then the indices of the tracks will change dynamically. If the
+  <a href="#media-resource">media resource</a> changes entirely, then all the previous
+  tracks will be removed and replaced with new tracks.</p>
+
+  <p>The <dfn id="dom-audiotracklist-length" title="dom-AudioTrackList-length"><code>AudioTrackList.length</code></dfn>
+  and <dfn id="dom-videotracklist-length" title="dom-VideoTrackList-length"><code>VideoTrackList.length</code></dfn>
+  attributes must return the number of tracks represented by their
+  objects at the time of getting.</p>
+
+  <p>The <a href="#supported-property-indices">supported property indices</a> of
+  <code><a href="#audiotracklist">AudioTrackList</a></code> and <code><a href="#videotracklist">VideoTrackList</a></code> objects
+  at any instant are the numbers from zero to the number of tracks
+  represented by the respective object minus one, if any tracks are
+  represented. If a <code><a href="#audiotracklist">AudioTrackList</a></code> or
+  <code><a href="#videotracklist">VideoTrackList</a></code> object represents no tracks, it has no
+  <a href="#supported-property-indices">supported property indices</a>.</p>
+
+  <p>To <a href="#determine-the-value-of-an-indexed-property">determine the value of an indexed property</a> for a
+  given index <var title="">index</var> in an
+  <code><a href="#audiotracklist">AudioTrackList</a></code> or <code><a href="#videotracklist">VideoTrackList</a></code> object
+  <var title="">list</var>, the user agent must return the
+  <code><a href="#audiotrack">AudioTrack</a></code> or <code><a href="#videotrack">VideoTrack</a></code> object that
+  represents the <var title="">index</var>th track in <var title="">list</var>.</p>
+
+  <p>The <dfn id="dom-audiotracklist-gettrackbyid" title="dom-AudioTrackList-getTrackById"><code>AudioTrackList.getTrackById(<var title="">id</var>)</code></dfn> and <dfn id="dom-videotracklist-gettrackbyid" title="dom-VideoTrackList-getTrackById"><code>VideoTrackList.getTrackById(<var title="">id</var>)</code></dfn> methods must return the first
+  <code><a href="#audiotrack">AudioTrack</a></code> or <code><a href="#videotrack">VideoTrack</a></code> object
+  (respectively) in the <code><a href="#audiotrack">AudioTrack</a></code> or
+  <code><a href="#videotrack">VideoTrack</a></code> object (respectively) whose identifier is
+  equal to the value of the <var title="">id</var> argument (in the
+  natural order of the list, as defined above). When no tracks match
+  the given argument, the methods must return null.</p>
+
+  <p>The <code><a href="#audiotrack">AudioTrack</a></code> and <code><a href="#videotrack">VideoTrack</a></code> objects
+  represent specific tracks of a <a href="#media-resource">media resource</a>. Each
+  track can have an identifier, category, label, and language. These
+  aspects of a track are permanent for the lifetime of the track; even
+  if a track is removed from a <a href="#media-resource">media resource</a>'s
+  <code><a href="#audiotracklist">AudioTrackList</a></code> or <code><a href="#videotracklist">VideoTrackList</a></code> objects,
+  those aspects do not change.</p>
+
+  <p>In addition, <code><a href="#audiotrack">AudioTrack</a></code> objects can each be enabled
+  or disabled; this is the audio track's <i>enabled state</i>. When an
+  <code><a href="#audiotrack">AudioTrack</a></code> is created, its <i>enabled state</i> must be
+  set to false (disabled). The <a href="#concept-media-load-resource" title="concept-media-load-resource">resource fetch algorithm</a>
+  can override this.</p>
+
+  <p>Similarly, a single <code><a href="#videotrack">VideoTrack</a></code> object per
+  <code><a href="#videotracklist">VideoTrackList</a></code> object can be selected, this is the
+  video track's <i>selection state</i>. When an
+  <code><a href="#videotrack">VideoTrack</a></code> is created, its <i>selection state</i> must
+  be set to false (not selected). The <a href="#concept-media-load-resource" title="concept-media-load-resource">resource fetch algorithm</a>
+  can override this.</p>
+
+  <p>The <dfn id="dom-audiotrack-id" title="dom-AudioTrack-id"><code>AudioTrack.id</code></dfn> and <dfn id="dom-videotrack-id" title="dom-VideoTrack-id"><code>VideTrack.id</code></dfn>
+  attributes must return the identifier of the track, if it has one,
+  or the empty string otherwise. If the <a href="#media-resource">media resource</a> is
+  in a format that supports the <cite>Media Fragments URI</cite>
+  fragment identifier syntax, the identifier returned for a particular
+  track must be the same identifier that would enable the track if
+  used as the name of a track in the track dimension of such a
   fragment identifier. <a href="#refsMEDIAFRAG">[MEDIAFRAG]</a></p>
 
-  <p>The <dfn id="dom-tracklist-getkind" title="dom-TrackList-getKind"><code>getKind(<var title="">index</var>)</code></dfn> method must return the category
-  of the track with index <var title="">index</var>, if there is one.
-  If there is no such track, then the method must instead throw an
-  <code><a href="#index_size_err">INDEX_SIZE_ERR</a></code> exception.</p>
+  <p>The <dfn id="dom-audiotrack-kind" title="dom-AudioTrack-kind"><code>AudioTrack.kind</code></dfn> and
+  <dfn id="dom-videotrack-kind" title="dom-VideoTrack-kind"><code>VideoTrack.kind</code></dfn>
+  attributes must return the category of the track, if it has one, or
+  the empty string otherwise.</p>
 
   <p>The category of a track is the string given in the first column
   of the table below that is the most appropriate for the track based
@@ -24855,108 +24938,108 @@
   what the category given in the cell in the first column of that row
   applies to; a category is only appropriate for an audio track if it
   applies to audio tracks, and a category is only appropriate for
-  video tracks if it applies to video tracks.</p>
+  video tracks if it applies to video tracks. Categories must only be
+  returned for <code><a href="#audiotrack">AudioTrack</a></code> objects if they are appropriate
+  for audio, and must only be returned for <code><a href="#videotrack">VideoTrack</a></code>
+  objects if they are appropriate for video.</p>
 
-  </div><table id="dom-TrackList-getKind-categories"><caption>Return values for <code title="dom-TrackList-getKind"><a href="#dom-tracklist-getkind">getKind()</a></code></caption>
+  </div><table id="dom-TrackList-getKind-categories"><caption>Return values for <code title="dom-AudioTrack-kind"><a href="#dom-audiotrack-kind">AudioTrack.kind()</a></code> and <code title="dom-VideoTrack-kind"><a href="#dom-videotrack-kind">VideoTrack.kind()</a></code></caption>
    <thead><tr><th>Category
      <th>Definition
      <th>Applies to...</th>
      <th>Examples
-   <tbody><tr><td>"<dfn id="dom-tracklist-getkind-alternate" title="dom-TrackList-getKind-alternate"><code>alternative</code></dfn>"
+   <tbody><tr><td>"<dfn id="value-track-kind-alternate" title="value-track-kind-alternate"><code>alternative</code></dfn>"
      <td>A possible alternative to the main track, e.g. a different take of a song (audio), or a different angle (video).
      <td>Audio and video.
      <td>Ogg: "audio/alterate" or "video/alternate".
 
-    <tr><td>"<dfn id="dom-tracklist-getkind-description" title="dom-TrackList-getKind-description"><code>description</code></dfn>"
+    <tr><td>"<dfn id="value-track-kind-description" title="value-track-kind-description"><code>description</code></dfn>"
      <td>An audio description of a video track.
      <td>Audio only.
      <td>Ogg: "audio/audiodesc".
 
-    <tr><td>"<dfn id="dom-tracklist-getkind-main" title="dom-TrackList-getKind-main"><code>main</code></dfn>"
+    <tr><td>"<dfn id="value-track-kind-main" title="value-track-kind-main"><code>main</code></dfn>"
      <td>The primary audio or video track.
      <td>Audio and video.
      <td>Ogg: "audio/main" or "video/main"; WebM: the "FlagDefault" element is set.
 
-    <tr><td>"<dfn id="dom-tracklist-getkind-sign" title="dom-TrackList-getKind-sign"><code>sign</code></dfn>"
+    <tr><td>"<dfn id="value-track-kind-sign" title="value-track-kind-sign"><code>sign</code></dfn>"
      <td>A sign-language interpretation of an audio track.
      <td>Video only.
      <td>Ogg: "video/sign".
 
-    <tr><td>"<dfn id="dom-tracklist-getkind-translation" title="dom-TrackList-getKind-translation"><code>translation</code></dfn>"
+    <tr><td>"<dfn id="value-track-kind-translation" title="value-track-kind-translation"><code>translation</code></dfn>"
      <td>A translated version of the main track.
      <td>Audio only.
      <td>Ogg: "audio/dub".
 
-    <tr><td>"<dfn id="dom-tracklist-getkind-none" title="dom-TrackList-getKind-none"><code></code></dfn>" (empty string)
+    <tr><td>"<dfn id="value-track-kind-commentary" title="value-track-kind-commentary"><code>commentary</code></dfn>"
+     <td>Commentary on the primary audio or video track, e.g. a director's commentary.
+     <td>Audio and video.
+     <td>No known formats expose this category at this time.
+
+    <tr><td>"<dfn id="value-track-kind-none" title="value-track-kind-none"><code></code></dfn>" (empty string)
      <td>No explicit kind, or the kind given by the track's metadata is not recognised by the user agent.
      <td>Audio and video.
      <td>Any other track type or track role.
 
   </table><div class="impl">
 
-  <p>The <dfn id="dom-tracklist-getlabel" title="dom-TrackList-getLabel"><code>getLabel(<var title="">index</var>)</code></dfn> method must return the label of
-  the track with index <var title="">index</var>, if there is one and
-  it has a label. If there is no such track, then the method must
-  instead throw an <code><a href="#index_size_err">INDEX_SIZE_ERR</a></code> exception. If there is
-  a track with index <var title="">index</var>, but it has no label,
-  then the method must return the empty string.</p>
+  <p>The <dfn id="dom-audiotrack-label" title="dom-AudioTrack-label"><code>AudioTrack.label</code></dfn> and
+  <dfn id="dom-videotrack-label" title="dom-VideoTrack-label"><code>VideoTrack.label</code></dfn>
+  attributes must return the label of the track, if it has one, or the
+  empty string otherwise.</p>
 
-  <p>The <dfn id="dom-tracklist-getlanguage" title="dom-TrackList-getLanguage"><code>getLanguage(<var title="">index</var>)</code></dfn> method must return the BCP 47
-  language tag of the language of the track with index <var title="">index</var>, if there is one and it has a language. If
-  there is no such track, then the method must instead throw an
-  <code><a href="#index_size_err">INDEX_SIZE_ERR</a></code> exception. If there is a track with
-  index <var title="">index</var>, but it has no language, or the user
+  <p>The <dfn id="dom-audiotrack-language" title="dom-AudioTrack-language"><code>AudioTrack.language</code></dfn>
+  and <dfn id="dom-videotrack-language" title="dom-VideoTrack-language"><code>VideoTrack.language</code></dfn>
+  attributes must return the BCP 47 language tag of the language of
+  the track, if it has one, or the empty string otherwise. If the user
   agent is not able to express that language as a BCP 47 language tag
   (for example because the language information in the <a href="#media-resource">media
   resource</a>'s format is a free-form string without a defined
-  interpretation), then the method must return the empty string.</p>
-
-  <hr><p>A <code><a href="#multipletracklist">MultipleTrackList</a></code> object represents a track list
-  where multiple tracks can be enabled simultaneously. Each track is
-  either enabled or disabled.</p>
-
-  <p>The <dfn id="dom-tracklist-isenabled" title="dom-TrackList-isEnabled"><code>isEnabled(<var title="">index</var>)</code></dfn> method must return true if there
-  is a track with index <var title="">index</var>, and it is currently
-  enabled, false if there is a track with index <var title="">index</var>, but it is currently disabled, and must throw
-  an <code><a href="#index_size_err">INDEX_SIZE_ERR</a></code> exception if there is no track with
-  index <var title="">index</var>.</p>
-
-  <p>The <dfn id="dom-tracklist-enable" title="dom-TrackList-enable"><code>enable(<var title="">index</var>)</code></dfn> method must enable the track with
-  index <var title="">index</var>, if there is one. If there is not,
-  it must instead throw an <code><a href="#index_size_err">INDEX_SIZE_ERR</a></code> exception.</p>
-
-  <p>The <dfn id="dom-tracklist-disable" title="dom-TrackList-disable"><code>disable(<var title="">index</var>)</code></dfn> method must disable the track with
-  index <var title="">index</var>, if there is one. If there is not,
-  it must instead throw an <code><a href="#index_size_err">INDEX_SIZE_ERR</a></code> exception.</p>
+  interpretation), then the method must return the empty string, as if
+  the track had no language.</p>
 
-  <p>Whenever a track is enabled or disabled, the user agent must
-  <a href="#queue-a-task">queue a task</a> to <a href="#fire-a-simple-event">fire a simple event</a> named
-  <code title="event-media-change">change</code> at the
-  <code><a href="#multipletracklist">MultipleTrackList</a></code> object.</p>
+  <p>The <dfn id="dom-audiotrack-enabled" title="dom-AudioTrack-enabled"><code>AudioTrack.enabled</code></dfn>
+  attribute, on getting, must return true if the track is currently
+  enabled, and false otherwise. On setting, it must enable the track
+  if the new value is true, and disable it otherwise. (If the track is
+  no longer in an <code><a href="#audiotracklist">AudioTrackList</a></code> object, then the track
+  being enabled or disabled has no effect beyond changing the value of
+  the attribute on the <code><a href="#audiotrack">AudioTrack</a></code> object.)</p>
 
-  <hr><p>An <code><a href="#exclusivetracklist">ExclusiveTrackList</a></code> object represents a track list
-  where exactly one track is selected at a time.</p>
+  <p>Whenever an audio track in an <code><a href="#audiotracklist">AudioTrackList</a></code> is
+  enabled or disabled, the user agent must <a href="#queue-a-task">queue a task</a>
+  to <a href="#fire-a-simple-event">fire a simple event</a> named <code title="event-media-change">change</code> at the
+  <code><a href="#audiotracklist">AudioTrackList</a></code> object.</p>
 
-  <p>The <dfn id="dom-tracklist-selectedindex" title="dom-TrackList-selectedIndex"><code>selectedIndex</code></dfn>
-  attribute must return the index of the currently selected track. If
-  the <code><a href="#exclusivetracklist">ExclusiveTrackList</a></code> object does not represent any
-  tracks, it must instead return &minus;1.</p>
+  <p>The <dfn id="dom-videotracklist-selectedindex" title="dom-VideoTrackList-selectedIndex"><code>VideoTrackList.selectedIndex</code></dfn>
+  attribute must return the index of the currently selected track, if
+  any. If the <code><a href="#videotracklist">VideoTrackList</a></code> object does not currently
+  represent any tracks, or if none of the tracks are selected, it must
+  instead return &minus;1.</p>
 
-  <p>The <dfn id="dom-tracklist-select" title="dom-TrackList-select"><code>select(<var title="">index</var>)</code></dfn> must select the track with index
-  <var title="">index</var>, if there is one, unselecting whichever
-  track was previously selected. If there is no track with index <var title="">index</var>, it must instead throw an
-  <code><a href="#index_size_err">INDEX_SIZE_ERR</a></code> exception.</p>
+  <p>The <dfn id="dom-videotrack-selected" title="dom-VideoTrack-selected"><code>VideoTrack.selected</code></dfn>
+  attribute, on getting, must return true if the track is currently
+  selected, and false otherwise. On setting, it must select the track
+  if the new value is true, and unselect it otherwise. If the track is
+  in a <code><a href="#videotracklist">VideoTrackList</a></code>, then all the other
+  <code><a href="#videotrack">VideoTrack</a></code> objects in that list must be unselected. (If
+  the track is no longer in a <code><a href="#videotracklist">VideoTrackList</a></code> object, then
+  the track being selected or unselected has no effect beyond changing
+  the value of the attribute on the <code><a href="#videotrack">VideoTrack</a></code>
+  object.)</p>
 
-  <p>Whenever the selected track is changed, the user agent must
-  <a href="#queue-a-task">queue a task</a> to <a href="#fire-a-simple-event">fire a simple event</a> named
-  <code title="event-media-change">change</code> at the
-  <code><a href="#multipletracklist">MultipleTrackList</a></code> object.</p>
+  <p>Whenever a track in a <code><a href="#videotracklist">VideoTrackList</a></code> that was
+  previously not selected is selected, the user agent must <a href="#queue-a-task">queue
+  a task</a> to <a href="#fire-a-simple-event">fire a simple event</a> named <code title="event-media-change">change</code> at the
+  <code><a href="#videotracklist">VideoTrackList</a></code> object.</p>
 
   <hr><p>The following are the <a href="#event-handlers">event handlers</a> (and their
   corresponding <a href="#event-handler-event-type" title="event handler event type">event handler
   event types</a>) that must be supported, as IDL attributes, by
-  all objects implementing the <code><a href="#tracklist">TrackList</a></code>
-  interface:</p>
+  all objects implementing the <code><a href="#audiotracklist">AudioTrackList</a></code> and
+  <code><a href="#videotracklist">VideoTrackList</a></code> interfaces:</p>
 
   <table><thead><tr><th><a href="#event-handlers" title="event handlers">Event handler</a> <th><a href="#event-handler-event-type">Event handler event type</a>
    <tbody><tr><td><dfn id="handler-tracklist-onchange" title="handler-TrackList-onchange"><code>onchange</code></dfn> <td> <code title="event-change">change</code>
@@ -26342,7 +26425,7 @@
 
   <p>The <dfn id="dom-media-texttracks" title="dom-media-textTracks"><code>textTracks</code></dfn>
   attribute of <a href="#media-element" title="media element">media elements</a> must
-  return an <span title="array host objects">array host object</span>
+  return an <a href="#array-host-objects" title="array host objects">array host object</a>
   for objects of type <code><a href="#texttrack">TextTrack</a></code> that is <i>fixed
   length</i> and <i>read only</i>. The same object must be returned
   each time the attribute is accessed. <a href="#refsWEBIDL">[WEBIDL]</a></p>
@@ -26375,7 +26458,9 @@
 
            attribute <a href="#function">Function</a>? <a href="#handler-texttrack-oncuechange" title="handler-TextTrack-oncuechange">oncuechange</a>;
 };
-<a href="#texttrack">TextTrack</a> implements <a href="#eventtarget">EventTarget</a>;</pre><dl class="domintro"><dt><var title="">textTrack</var> . <code title="dom-TextTrack-kind"><a href="#dom-texttrack-kind">kind</a></code></dt>
+<a href="#texttrack">TextTrack</a> implements <a href="#eventtarget">EventTarget</a>;
+
+typedef <a href="#texttrack">TextTrack</a>[] <dfn id="texttracklist">TextTrackList</dfn>;</pre><dl class="domintro"><dt><var title="">textTrack</var> . <code title="dom-TextTrack-kind"><a href="#dom-texttrack-kind">kind</a></code></dt>
    <dd>
     <p>Returns the <a href="#text-track-kind">text track kind</a> string.</p>
    </dd>
@@ -26735,15 +26820,15 @@
   cue">cues</a> in the list represented by the
   <code><a href="#texttrackcuelist">TextTrackCueList</a></code> object.</p>
 
-  <p>The <span>supported property indicies</span> of a
+  <p>The <a href="#supported-property-indices">supported property indices</a> of a
   <code><a href="#texttrackcuelist">TextTrackCueList</a></code> object at any instant are the numbers
   from zero to the number of <a href="#text-track-cue" title="text track cue">cues</a>
   in the list represented by the <code><a href="#texttrackcuelist">TextTrackCueList</a></code> object
   minus one, if any. If there are no <a href="#text-track-cue" title="text track
-  cue">cues</a> in the list, there are no <span>supported property
-  indicies</span>.</p>
+  cue">cues</a> in the list, there are no <a href="#supported-property-indices">supported property
+  indices</a>.</p>
 
-  <p>To <span>determine the value of an indexed property</span> for a
+  <p>To <a href="#determine-the-value-of-an-indexed-property">determine the value of an indexed property</a> for a
   given index <var title="">index</var>, the user agent must return
   the <var title="">index</var>th <a href="#text-track-cue">text track cue</a> in the
   list represented by the <code><a href="#texttrackcuelist">TextTrackCueList</a></code> object.</p>
Received on Thursday, 30 June 2011 23:52:58 GMT

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