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Re: [media] alt technologies for paused video (and using ARIA)

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Thu, 12 May 2011 10:26:16 +1000
Message-ID: <BANLkTiny85=CJ6DZ98Kzyo0UBxH-bEfm4Q@mail.gmail.com>
To: John Foliot <jfoliot@stanford.edu>
Cc: David Singer <singer@apple.com>, HTML Accessibility Task Force <public-html-a11y@w3.org>, James Craig <jcraig@apple.com>, Michael Cooper <cooper@w3.org>
On Thu, May 12, 2011 at 9:29 AM, John Foliot <jfoliot@stanford.edu> wrote:
> David Singer wrote:
>>
>> I think the point is that the poster and the aria-label are both about
>> the video (they are peers)
>
> Exactly.

That's exactly the kind of impression that I am trying to avoid. There
is no need to provide a label on the video - @id does that perfectly
well. There is also no need to provide an alternative description of
the video content: @alt is not there to provide a summary of the video
content. Text alternatives are about providing text alternatives to
what only a sighted user sees and we are talking about the pause
situation here, so the video and the poster are identical in this
situation.


>>  so it might be better to say
>>
>>  <video poster="media/ClockworkOrangetrailer.jpg" controls
>>         aria-label="A Clockwork Orange movie trailer">
>>    <source src="media/ClockworkOrangetrailer.mp4">
>>    <source src="media/ClockworkOrangetrailer.webm">
>>    <source src="media/ClockworkOrangetrailer.ogv">
>>  </video>
>
> For accessibility API mapping, naming the <video> object as "A Clockwork
> Orange movie trailer" would be acceptable,

No, it's not acceptable - it provides more information than the
placeholder frame provides, which is not what text alternatives are
about.


> although I still do not believe
> that it solves the broader problem statement: what is the 'textual
> alternative' to this resource, for users and user-agents that do not
> support/consume graphical objects? Aria-label is not text that is intended
> to render on screen, it is more akin to an ID, in that it names the object
> but does not display onscreen text.
>
> I am leery as well of making a one-time exception to aria-label when used
> with <video>, as this adds additional complexity to the authoring stage
> (and perhaps also to the browser/user agents).

Fair enough.

> The <video> element can take aria-label today with no change to the
> specification - re-envisioning aria-label to provide alternative text
> however is incorrect.

Is that really the case? IIUC, neither aria-label nor alt are
conforming attributes on media elements and screen readers ignore
them. A test with ChromeVox confirms this, though I cannot test any
other screenreader on my mac.


Silvia.
Received on Thursday, 12 May 2011 00:35:05 GMT

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