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Re: [media] Moving forward with captions / subtitles

From: Philip Jägenstedt <philipj@opera.com>
Date: Mon, 15 Feb 2010 14:35:58 +0800
To: "Eric Carlson" <eric.carlson@apple.com>
Cc: "Silvia Pfeiffer" <silviapfeiffer1@gmail.com>, "HTML Accessibility Task Force" <public-html-a11y@w3.org>
Message-ID: <op.u75ol8muatwj1d@philip-pc>
On Mon, 15 Feb 2010 14:25:42 +0800, Eric Carlson <eric.carlson@apple.com>  
wrote:

>
> On Feb 14, 2010, at 9:34 PM, Philip Jägenstedt wrote:
>
>> Complex case:
>>
>> <video>
>>  <trackgroup role="captions">
>>    <track src="captions.srt">
>>    <!-- lots of tracks -->
>>  </trackgroup>
>>  <trackgroup role="karaoke">
>>    <!-- lots of tracks -->
>>  </trackgroup>
>>  <!-- lots of groups -->
>> </video>
>>
>> <track>s in a <trackgroup> are mutually exclusive while tracks in  
>> different groups are not. This is the only semantics expressed --  
>> grouping doesn't have to be based on role. By default all tracks are  
>> mutually exclusive.
>>
>> lang="" is already inherited, perhaps we could do the same for role=""  
>> to that either or both can be specified on <trackgroup>?
>>
>> As long as native browser controls can find a suitable string for each  
>> track group, using the grouping in menus would be acceptable since  
>> usually there will be no groups at all and thus the common case doesn't  
>> suffer from it.
>>
>> Would this be an acceptable solution?
>>
>> Note: there is no <source> element in this proposal, because there's no  
>> need for it.
>>
>
>   I don't see how you will list alternate sources for a role. Can you  
> please show an explicit example of how you list alternate tracks where  
> you have "<!-- lots of tracks -->" now? For example, list four different  
> language alternates for each of the roles you list in the example above.

<trackgroup role="subtitles">
   <track src="subtitles.en.srt" lang="en">
   <track src="subtitles.sv.srt" lang="sv">
   <track src="subtitles.fr.srt" lang="fr">
   <track src="subtitles.zh.srt" lang="zh">
</trackgroup>
<trackgroup role="captions">
   <track src="captions.en.srt" lang="en">
   <track src="captions.sv.srt" lang="sv">
   <track src="captions.fr.srt" lang="fr">
   <track src="captions.zh.srt" lang="zh">
</trackgroup>

role="" isn't what makes the tracks alternative, it's that they are in the  
same <trackgroup>. If <trackgroup> isn't used then all tracks are in the  
same implicit group and are mutually exclusive.

(I think my previous suggestion of using <track> as the grouping element  
and <source> for the individual track was quite confusing.)

-- 
Philip Jägenstedt
Core Developer
Opera Software
Received on Monday, 15 February 2010 06:36:43 GMT

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