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Re: Issue 142: Video Poster [Was: Reminder: January Change Proposal Deadlines]

From: David Singer <singer@apple.com>
Date: Wed, 5 Jan 2011 09:15:05 -0800
Cc: Janina Sajka <janina@rednote.net>, John Foliot <jfoliot@stanford.edu>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Message-Id: <2A122979-1E94-480C-A7CB-6D6C0F1C83CD@apple.com>
To: Laura Carlson <laura.lee.carlson@gmail.com>
Hi Laura, everyone,

I'm sorry, I was stunningly unclear on both points!

1)  I meant to say, if you wish to have a page that shows an image that is semantically distinct from the video which eventually replaces it when some event happens, you have all the tools you need in HTML/CSS/script already, and if you use these tools, then that image can be fully associated with alt text etc. as it is a normal HTML image. So I was not talking of suppling alt text, but of a semantically distinct image.  If, on the other hand, the image is a transient place-holder that has the same semantics as the video, and is predominantly there to avoid having blank space on the page, then the existing state is fine (provided we have good accessibility provisions for the video itself, which I currently am unsure about).

2) It's a minor point about where text is.  

<image src="..." alt="this text is in the markup" />
<image src="...">
  <alt lang="en-US">this text is body text</alt>

The first has user-presented text in markup;  the second has it (correctly, I feel) in the body text, where it's amenable to styling, language attribution (as in this example), and so on.

I fully support the design principle of providing accessibility (I hope this doesn't need saying).

On Jan 5, 2011, at 6:14 , Laura Carlson wrote:

> Hi David and everyone,
> Janina wrote:
>>> May I amend my assertion to say that the need for alt text is not
>>> controversial among the TF?
> David wrote:
>> If you *want* to show something that is semantically different, and needs
>> its own labeling, then it is easy to do;  show a div
> Does this mean that you consider it more of a want than a need?  Do
> you consider some sort of mechanism (other than a div) which supplies
> a text alternative for a video key frame  is not a functional
> requirement for HTML5?
>> I am also concerned that 'alt' breaks a very fundamental design principle.
> This is a core disagreement. "Access for people with disabilities is
> essential. This does not mean that features should be omitted if not
> all users can fully make use of them but rather that
> alternative/equivalent mechanisms must be provided. Example: The image
> in the img element is not perceivable by blind users. That is not a
> reason to drop the element from the specification, but is a reason to
> require mechanisms for adding text alternatives." [1]
> Best Regards,
> [1] http://www.w3.org/html/wg/wiki/AccessibilityDesignPrinciple
> Laura
> -- 
> Laura L. Carlson

David Singer
Multimedia and Software Standards, Apple Inc.
Received on Wednesday, 5 January 2011 17:16:08 UTC

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