Fwd: [Bug 17002] Specify SourceID to AudioTrack.id & VideoTrack.id mappings

Hi guys,

There's a divergence between the HTML spec and our media fragment spec
on how to create track URLs (details on the bug, see below).

Ian obviously introduced an @id attribute on audio and video tracks to
enable labelling through HTML (without having to rely on a name inside
the video resources). We should adapt our example to this:

<video id="v1" src="video" controls> </video>

<script type="text/javascript">
  var video = document.getElementsByTagName("video")[0];
  var track_names = [];
  var idx = 0;

  for (i=0; i< video.audioTracks.length; i++, idx++) {
    track_names[idx] = video.audioTracks[i].id;
  }
  for (i=0; i< video.videoTracks.length; i++, idx++) {
    track_names[idx] = video.audioTracks[i].id;
  }
  for (i=0; i< video.textTracks.length; i++, idx++) {
    track_names[idx] = video.textTracks[i].label;
  }
</script>

Regards,
Silvia.


---------- Forwarded message ----------
From:  <bugzilla@jessica.w3.org>
Date: Wed, May 16, 2012 at 3:06 AM
Subject: [Bug 17002] Specify SourceID to AudioTrack.id & VideoTrack.id mappings
To: silviapfeiffer1@gmail.com


https://www.w3.org/Bugs/Public/show_bug.cgi?id=17002

--- Comment #4 from Aaron Colwell <acolwell@chromium.org> 2012-05-15
17:06:16 UTC ---
(In reply to comment #3)
> getElementById should certainly not find AudioTrack, VideoTrack or TextTrack,
> as they are not HTML elements at all. AFAICT, the main purpose of exposing id
> on audio and video tracks if for integration with Media Fragments.

Ok good this matches my understanding as well.

The Media Fragment spec and HTML5 spec appear to be out of sync. The HTML5 spec
indicates that AudioTrack.id & VideoTrack.id contain the strings that should be
used in the 'track dimension' of the fragment URI
(http://dev.w3.org/html5/spec/media-elements.html#dom-audiotrack-id). The
"Track Dimension" text and example in the Media Fragments spec seems to imply
that the 'label' attributes on these objects should be use for the track
dimension
(http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-spec/#naming-track).
It seems to me that the Media Fragment spec is wrong here.

Do you agree with this interpretation? If so I think it means 2 bugs need to be
filed. One to update the text of Media Fragment spec to reference id instead of
label. A second one would be filed to add an id attribute to TextTrack so it
matches AudioTrack & VideoTrack.

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Received on Wednesday, 16 May 2012 04:23:28 UTC