W3C home > Mailing lists > Public > public-html-a11y@w3.org > April 2011

Re: text track associations

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Sat, 9 Apr 2011 20:22:17 +1000
Message-ID: <BANLkTintYpe9TNrfQSfE1L-7cnfrbT4=nQ@mail.gmail.com>
To: Sean Hayes <Sean.Hayes@microsoft.com>
Cc: David Singer <singer@apple.com>, Mark Watson <watsonm@netflix.com>, Eric Carlson <eric.carlson@apple.com>, Ian Hickson <ian@hixie.ch>, "public-html-a11y@w3.org" <public-html-a11y@w3.org>
On Sat, Apr 9, 2011 at 5:01 AM, Sean Hayes <Sean.Hayes@microsoft.com> wrote:
> Yes they will share a timeline once they are glued together, that's only one of the issues here. They will also need to share a display space. I want to see how this example would be marked up using the 'controller' model. Do I put the director captions inside the <audio> that is the director commentary? If so, how do they show up in the other video space. If not, what information does the UA use to associate the second caption track with the remote audio element?
>
> For example:
> <video id=vid mediagroup=set src=mainvideo.vid >
>    <track kind=captions id=main>
> </video>
>
> <audio mediagroup=set src=director.aud >
>    <track kind=captions id=director>
> </audio>
>
> how do captions.director end up getting displayed in video.vid?
>

As it stands right now, in this example, the captions in the audio
track are not displayed, so have to be mapped onto the screen through
the JavaScript API. So, you can create a display area that matches
where you want to place them and you can make it replace the main
captions. This is acceptable for complex situation, IMHO.

However, we have a similar issue with captions for audio description
tracks, which should probably be more commonly displayed as an
alternative or addition to the normal captions. I'd probably encourage
the Web author to add that in another track with the full transcript
of both the captions and audio descriptions as you did in the example
below:



> Alternately if I do:
> <video id=vid mediagroup=set src=mainvideo.vid >
>    <track kind=captions id=main>
>    <track kind=captions id=director>
> </video>
>
> <audio mediagroup=set src=director.aud >
> </audio>
>
> Then how do I prevent the director captions being offered as an option for the ordinary video until the second audio is selected?

In the case of the director's track, I'd probably prefer the above
markup. For audio descriptions probably this one and then it's fine
when both the captions and audio descriptions are displayed because
they would occupy different times anyway.


Cheers,
Silvia.
Received on Saturday, 9 April 2011 10:23:04 UTC

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