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RE: [media] handling multitrack audio / video

From: John Foliot <jfoliot@stanford.edu>
Date: Wed, 27 Oct 2010 23:08:14 -0700 (PDT)
To: "'Silvia Pfeiffer'" <silviapfeiffer1@gmail.com>, "'Frank Olivier'" <Frank.Olivier@microsoft.com>
Cc: "'HTML Accessibility Task Force'" <public-html-a11y@w3.org>
Message-ID: <034701cb7666$7ebeb400$7c3c1c00$@edu>
> <Frank.Olivier@microsoft.com> wrote:
> > Overall feedback from the Internet Explorer team:
> >
> > Option 1 - Overloading <track> and keeping the DOM parsing very
> simple would be the most elegant way to proceed, with every track
> having a 'kind' attribute - Generally, I expect to be able to activate
> a single alternate track of a particular type (Also, this would also
> sync up well with a simple javascript API - I would expect that I (as
> an author) would be able to enumerate a flat list of alternate
> representations, with metadata that indicates the kind.

There has been some mention of metadata here before. I am curious as to
how and what this metadata might look like (as I am unsure of this). Do
you have a specific spec or idea regarding this metadata (schema)?
(thanks)

> >
> > Additionally, it would be prudent to leave exact conformance (when
> enabling/disabling alternate tracks) as a 'quality of implementation'
> issue - For example, with multiple alternate audio tracks, there will
> certainly be some (mobile) devices where the user agent is only able to
> play back one audio or video track at a time due to hardware
> constraints; some devices may only have enough screen real estate to
> display a single caption track.

This was a known consideration when I undertook the Must/Should/May review
in the Requirements Checklist[1]. I have welcomed feedback previously, and
if any of those mappings require further discussion it is most welcome. We
have also ensured that the mappings reflect the status requirements in
existing W3C accessibility specifications (WCAG and UAAG - likely UAAG
being more relevant in this particular discussion), but again happy to
discuss any particular issue. 

JF
[1] http://www.w3.org/WAI/PF/HTML/wiki/Media_Accessibility_Checklist  
Received on Thursday, 28 October 2010 06:08:55 GMT

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