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Expand on how to source TextTrack objects from types of inband text tracks typically used in UAs, given input from the Inband Text Track CG. This includes: 1. Determining what tracks in a media resource are actually identified as text tracks 2. The order in which the identified tracks are added to the TextTrackList 3. How to fill the .id, .kind, .label, and .language attributes on the created TextTrack object (these are actually applicable to AudioTrack and Video Track objects, too) The proposed patch is here: https://github.com/w3c/html/commit/5fbd9199cc711d8ae9155da58be3d4368272e00d . The Inband Text Track CG has collated information on their wiki here: https://www.w3.org/community/inbandtracks/wiki/Main_Page#Audio.2FVideo.2FText_Track_Creation * "Track order" relates to point 2 above, * "Track id, label, language" relate to point 3 above, * "TextTrack Creation - kind" relates to point 1 & 3 above The specifications that I based the patch on are as follows: * Ogg (there were some bugs in Ogg and I completed the information): https://wiki.xiph.org/SkeletonHeaders and https://www.xiph.org/ogg/doc/framing.html (for skeleton-free Ogg) * WebM: http://www.webmproject.org/docs/container/ http://matroska.org/technical/specs/index.html * MPEG-2: http://www.itu.int/rec/T-REC-H.222.0-201206-I * ISOBMFF/MEG-4: http://standards.iso.org/ittf/PubliclyAvailableStandards/c061988_ISO_IEC_14496-12_2012.zip * DASH: http://standards.iso.org/ittf/PubliclyAvailableStandards/c057623_ISO_IEC_23009-1_2012.zip Where it was unclear, I used the input from the CG wiki. The patch has been reviewed and ok-ed by the CG (see bug #24997). I'm looking to have the patch adjusted and applied in a manner that suits the WHATWG style.
Shouldn't this just be in a wiki somewhere? It seems like it needs specific text per-format, and HTML itself seems like a poor place to put that.
A first draft spec is now available at http://rawgit.com/silviapfeiffer/HTMLSourcingInbandTracks/master/index.html . The following changes still need to be added to the HTML spec - these are about the sourcing of the inBandMetadataTrackDispatchType attribute: 1.) Typo for Ogg: <dt>If the <span>media resource</span> is an Ogg file</dt> The <span>text track in-band metadata track dispatch type</span> must be set to the value of the Name header field. That should be the 'role' header field, and not the "Name" header field. 2.) Add for DASH: <dt>If the <span>media resource</span> is a DASH media resource</dt> <dd>The <span>text track in-band metadata track dispatch type</span> must be set to the concatenation of the "AdaptationSet" element attributes and all child Role descriptors. <a href="#refsDASH">[DASH]</a></dd>
I like it! What URL should I use to reference that?
Bug 25733 [1] has been opened to add an HTML5 reference to the sourcing spec. [1] https://www.w3.org/Bugs/Public/show_bug.cgi?id=25733
Spec is now available at http://dev.w3.org/html5/html-sourcing-inband-tracks/ . I've made use of it via https://github.com/w3c/html/commit/c3a32873e10c45fc948541ca229914d4cf07cdee
The version at http://dev.w3.org/html5/html-sourcing-inband-tracks/ captures known (at least to me) use cases for MPEG-2 TS, ISOBMFF and DASH.
Looks like this got fixed at some point already.