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Re: Is longdesc a good solution? (was: Acessibility of <audio> and <video>)

From: Leif Halvard Silli <lhs@malform.no>
Date: Mon, 08 Sep 2008 02:18:33 +0200
Message-ID: <48C46F59.3010909@malform.no>
To: Lachlan Hunt <lachlan.hunt@lachy.id.au>
CC: public-html@w3.org, 'W3C WAI-XTECH' <wai-xtech@w3.org>

Lachlan Hunt 2008-09-07 21.53:

> Leif Halvard Silli wrote:
>> <video>: Would you propose the use of <object> instead of <video> when
>> HTML fallback for videos is wanted as well? (The current discussion
>> started with a proposal to add @longdesc to <video>.)
> No,

Do you even see <object> as better than an <img> with longdesc?

> because <object> lacks the APIs that makes <video> useful, and

If you only meant that it will be simpler to get good results with 
<video>, then the same can be said about <img> vs <object> as 
well. However, that would not be a valid argument against using 
<object> *when needed*, whether for image or video content.

> because, as has already been explained countless times, any
> alternative content for video should be made available to everyone.

This is the same viewpoint that you have with regard to long image 
fallback. I see no justification for a sharp line between short 
and long fallback when it comes to "available to everyone".

> Neither longdesc nor <object> fallback successfully meets that
> condition.

<video> belongs to the future. As do any improvements we may add 
to @longdesc or <object>. HTML 5 can say that UAs must allow all 
users access to the fallback of @longdesc, <object> (or that of 
<video>). See our previous exchange regarding @longdesc. [1][2]

> The only reasonable solution is to include any alternative
> content or links to it elsewhere in the page, preferably
> nearby.

It is difficult to subscribe to this being the only reasonable.

Even on a dedicated video site with transcripts, where referring 
to the transcripts with normal links perhaps would be the best way 
(until all users can have easy access to @longdesc that is), it 
could, from a usability viewpoint, still be useful for AT users if 
@longdesc points to the transcript.

For example, most or all UAs supporting it (e.g. iCab and Jaws) 
would open a @longdesc URI in a new window. The user then gets a 
dedicated window with the transcript. After reading it, the window 
can just be closed, and the user will be back to were he was 
before opening the @longdesc URI, ready for next transcript. I 
talked about this in Februar. [3]

Quite practical. But not possible on an ordinary link, unless you 
e.g. use rel=longdesc  - which would be much more error prone - or 
if the user manualy opens it in a new window.

[1] http://lists.w3.org/Archives/Public/public-html/2008Sep/0179.html
[2] http://lists.w3.org/Archives/Public/public-html/2008Sep/0191.html
[3] http://www.w3.org/mid/47BA908A.9010200@malform.no
leif halvard silli
Received on Monday, 8 September 2008 00:19:25 UTC

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