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RE: [media] handling multitrack audio / video

From: Sean Hayes <Sean.Hayes@microsoft.com>
Date: Fri, 3 Dec 2010 11:14:22 +0000
To: Philip Jägenstedt <philipj@opera.com>, Silvia Pfeiffer <silviapfeiffer1@gmail.com>, Eric Carlson <eric.carlson@apple.com>
CC: Geoff Freed <geoff_freed@wgbh.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>, Frank Olivier <Frank.Olivier@microsoft.com>
Message-ID: <8DEFC0D8B72E054E97DC307774FE4B91330C369C@DB3EX14MBXC315.europe.corp.microsoft.com>
Well at the risk of channeling Dick Bulterman:

  <...>
      <switch syncmaster >  <!-- this element selected from this group provides the timing -->
         <video src=" mainMovieOC.ogg " systemSubtitle  systemLanguage="zh-Hant"  ... />   <!-- this has open subtitles in trad chinese-->
         <video src="mainMovie.ogg" ... />   <!-- the default with no constraints -->
    </switch> 
      <switch> 
         <video src=" transMovieBSL.ogg " systemLanguage="sgn-GB"  ... />   <!-- a BSL sign language translation to be synced to the main movie-->
         <video src="transMovieASL.ogg" systemLanguage="sgn-US"   ... />   <!-- an ASL sign language translation to be synced to the main movie -->
    </switch>
     <switch>
      <audio src="mainMovie.en.mp3" systemAudioDesc systemLanguage="en" ... />   <!-- alternate described soundtracks in a variety of languages -->
      <audio src="mainMovie.nl.mp3" systemAudioDesc systemLanguage="nl" ... />
      <audio src="mainMovie.de.mp3" systemAudioDesc  systemLanguage="de"  ... />
    </switch>
    <switch> 
       <text src="movie-sub-en.rtx" systemLanguage="en  systemCaptions ... /> <!-- alternate text tracks for subtitles and captions -->
       < text src="movie-sub-de.rtx" systemLanguage="de" systemSubtitle ... /> 
       < text src="movie-sub-nl.rtx" systemLanguage="nl" systemSubtitle  ... /> 
    </switch>
  </...>

You might need to shuffle things around a bit to fit in HTML, and you could replace the systemXXX attributes with media queries.

-----Original Message-----
From: public-html-a11y-request@w3.org [mailto:public-html-a11y-request@w3.org] On Behalf Of Philip Jägenstedt
Sent: 03 December 2010 10:01
To: Silvia Pfeiffer; Eric Carlson
Cc: Geoff Freed; HTML Accessibility Task Force; Frank Olivier
Subject: Re: [media] handling multitrack audio / video

On Thu, 02 Dec 2010 16:41:56 +0100, Eric Carlson <eric.carlson@apple.com>  
wrote:

>
> On Dec 2, 2010, at 6:31 AM, Silvia Pfeiffer wrote:
>
>>
>> For #3 there is not much to do actually - just having a means to
>> switch between resources would be sufficient. That means could be a
>> button underneath the video or a second tab with the video and lets
>> the user change between the main video and it's auditory-only
>> counterpart. I wonder if we even need special accessibility features
>> for this.
>>
> The idea we have long talked about to use media queries on a <source>  
> element to label the accessibility features of its resource could be  
> very useful here. It would allow an author to include videos with and  
> without open audio descriptions in the markup:
>
>    <video controls>
>        <source src="trailer_with_open_captions.m4v"  
> media="accessibility(audiodescription:yes)" >
>        <source src="trailer.m4v">
>    </video>
>
> and the user agent will automatically choose the captioned file if the  
> user's preferences say they want them.

Anything that overloads <source> will suffer from the problem that users  
can't switch between versions once one has been selected. The resource  
selection algorithm is already quite messy. Today, <source> is supposed to  
be used for equivalent resources where only the format differs. For  
alternative tracks, I think we really need something different. I'd say  
<track>, but that's really for *additional* tracks so far, not  
alternatives...

-- 
Philip Jägenstedt
Core Developer
Opera Software


Received on Friday, 3 December 2010 11:15:40 GMT

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