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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 10:05:11 +1000
Message-ID: <BANLkTin7ojktz5Zr=sMuR=onHGPmh8LxEg@mail.gmail.com>
To: Léonie Watson <lwatson@nomensa.com>
Cc: John Foliot <jfoliot@stanford.edu>, HTML Accessibility Task Force <public-html-a11y@w3.org>, James Craig <jcraig@apple.com>, Michael Cooper <cooper@w3.org>
Hi Leonie,

On Thu, May 12, 2011 at 8:20 AM, Léonie Watson <lwatson@nomensa.com> wrote:
> John Foliot wrote:
> "
>> When a screen reader (for example) announces aloud "A Clockwork Orange
>> movie poster" it is labeling something completely different than the
>> movie; it is inappropriate and confusing to suggest otherwise and
>> contrary to what aria-label has been defined to express."
> Silvia Pfeiffer replied:
> "It's a label for the video element, which in the instance of non-autoplay is simply the content of the placeholder frame. So, it's completely correct."
> Silvia,
>        I think this approach looks at it from the wrong perspective. Having a label for the video element may be technically correct, but I don't think it reflects the user perspective all that well.
>        When I arrive at a video (with my screen reader), I want to know what that static image/frame contains. At that moment in time, in the world according to me and my screen reader, that image exists entirely in its own right. It might be a still from the video, it might be a separate image. It might be related content, it might be a completely unrelated corporate ident (for example).

That is correct. However, what we do with alt technologies is to
provide text alternatives for something that is on screen and visible
to a sighted user. For a paused video, it is the placeholder frame
that a sighted user sees. A sighted user sees nothing more than that.
Therefore, the alt text that we need to provide for the video must
describe the content of the placeholder frame, independent of where
that placeholder frame comes from and what it contains.

>        Wanting to know what that image contains doesn't prevent me from wanting to know what the video contains. There may well be overlap, but equally they could be worlds apart.

Indeed. A sighted user wants to know this, too. If the placeholder
frame is all a sighted user sees and there is no additional text, it
is the only impression that is available for explaining what the video

Fortunately, we often have some text description underneath the video
that explains the content a little better. Since it is text, there is
no need to make it further accessible other than possibly linking to
it with aria-describedby.

>        Technically speaking, the image may well be part of the video element. This is a technical specification of course, but it's also the tool we'll use to build user experiences, and I don't think this composite approach supports that goal.

I think it does. Example 3 on the wiki page should now provide a
better explanation. I've marked up the images with caption text now,
so hopefully they can be represented by a screenreader.

Received on Thursday, 12 May 2011 01:06:36 UTC

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