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Proposed substantive change to media accessibility (Issue 2490)

From: Sean Hayes <Sean.Hayes@microsoft.com>
Date: Mon, 25 Feb 2008 20:19:08 +0000
To: WCAG <w3c-wai-gl@w3.org>
Message-ID: <90EEC9D914694641A8358AA190DACB3D1B498C9CCD@EA-EXMSG-C334.europe.corp.microsoft.com>
As discussed on the last teleconf, here is my proposal and rationale for re-levelling the media accessibility requirements.

As you will recall in the previous email, In the current draft, at level A the possible options for synchronised media are:

1)      Provide a descriptive identification, a full text equivalent and caption all of the prerecorded audio

2)      Provide a descriptive identification, audio describe all of the prerecorded video and caption all of the prerecorded audio

3)      Provide a descriptive identification, a full text equivalent, audio describe all of the prerecorded video and caption all of the prerecorded audio


Thus as we currently have it, a full text equivalent is seen as adequate access (indeed preferred - given its appearance again at AAA) at level A for people who have sight disabilities, but not for people who have hearing disabilities. I guess the rationale for this unevenness is recorded somewhere, I don't recall from the previous discussions what it was.

 In the discussion, I raised as an issue the relative difficulties of producing each of these, and the real danger of media based websites disregarding WCAG as a whole because they will be unable to meet the caption and AD provisions, but that was rejected as a criterion for setting level, so I'm not going to dwell on it too much here; even though I think it's very important. But I do think the discrepancy above will eventually be picked up on as a fault of WCAG, once it becomes clear what the choices actually are.

The full text alternative is very a high bar and exposes information in a way which would make most copyright holders very uncomfortable, so it seems incongruous to me at level A, even as an option, since these issues are certainly going to make it very problematic for most mainstream media providers; and option 2 above is probably going to be the only practical choice.


In my previous email, I introduced a concept of 'non-blocking', which required that any information needed to correctly comprehend/use the page was not presented in media alone, and could be used as a more provider-friendly version of 'full text alternative' or 'text alternative' to operate at level A. This would also be more technology neutral and future proof; for example if a text based description technology came along, this would actually be prevented by the current rules which require AD to be in the soundtrack; even though it could be rendered by speech synthesis or delivered via a refreshable Braille device, which might be more appropriate in a mixed audience.

Another example is requiring a text equivalent for an MP3 tune; it would seem that at minimum only a complete transcript of the lyrics is allowed to achieve level A (it's pretty ambiguous  whether the draft would allow captions in this case). It seems to me that users that are unable to hear would probably not be blocked on a 'pay to downlowd' music site if they could not read the lyrics of a snippet of a track, and that the name of the tune, artist and possibly some recording notes/parental guidance would probably be adequate for them to make a purchase decision.



The current full text alternative requires:

"document including correctly sequenced text descriptions of all visual settings, actions, speakers, and non-speech sounds, and transcript of all dialogue combined with a means of achieving any outcomes that are achieved using interaction (if any) during the synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef> "
And text equivalent requires:

"programmatically determined text<http://www.w3.org/WAI/GL/WCAG20/#textdef> that is used in place of non-text content<http://www.w3.org/WAI/GL/WCAG20/#non-text-contentdef>, or text that is used in addition to non-text content and referred to from the programmatically determined<http://www.w3.org/WAI/GL/WCAG20/#programmaticallydetermineddef> text"

Both of these have serious IP implications for providers, whereas non-blocking would be:

content in a web page which is not used as the only means of conveying information needed to comprehend a web page or perform an action needed to operate a web page.

This ensures a basic level of accessibility in the presence of media and allows much more flexibility at level A. Moving captions and AD at level AA still allows jurisdictions which require them to set AA as the minimum bar, which I suspect will be the typical case, but allows providers which can't meet that to still have something to aim at, rather than not bothering at all.


If we choose to address the issues above, then as I see it three possible plans would be:

Plan 1 provide equity by allowing a full text equivalent for audio disabilities, where at level A the options for synchronised media would be:

1)      Provide a descriptive identification, and a full text equivalent

2)      Provide a descriptive identification, audio describe all of the prerecorded video and caption all of the prerecorded audio

3)      Provide a descriptive identification, a full text equivalent, audio describe all of the prerecorded video and caption all of the prerecorded audio

At level AA, remove option (1) and add live to the other two options.


Plan 2 provide equity by removing the option of full text equivalent for visual disabilities at level A, so that at level A the options for synchronised media would be:

1)      Provide a descriptive identification, audio describe all of the prerecorded video and caption all of the prerecorded audio

2)      Provide a descriptive identification and a full text equivalent

At level AA add live to option (1).


Plan 3 provide equity and allow a more readily achieved basic accessibility option, where at level A the options for synchronised media are:

1)      Provide a descriptive identification, and  ensure media is non blocking



At level AA).
Provide a descriptive identification, ensure media is non blocking , audio describe all of the prerecorded video and caption all of the audio

My preference (obviously) is plan 3 so I have proposed text for that below, Plan 2 is IMO the one that will be 'real world' based on the existing draft and is a smallish delta from my previous post.







1.1.1 Non-text Content: All non-text content<http://www.w3.org/WAI/GL/WCAG20/#non-text-contentdef> has a text alternative<http://www.w3.org/WAI/GL/WCAG20/#text-altdef> that presents equivalent information, except for the situations listed below. (Level A) How to Meet 1.1.1<http://www.w3.org/WAI/WCAG20/quickref/20071218/Overview.php#qr-text-equiv-all> Understanding 1.1.1<http://www.w3.org/WAI/GL/WCAG20/WD-UNDERSTANDING-WCAG20-20071218/text-equiv-all.html>

 *   Controls, Input: If it is a control or accepts user input, then it has a name<http://www.w3.org/WAI/GL/WCAG20/#namedef> that describes its purpose. (See also Guideline 4.1<http://www.w3.org/WAI/GL/WCAG20/#ensure-compat>.)
 *   Media: If it is (1) synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef>, (2) [audio-only] or (3) [video-only] content.

Note: media is covered under Guideline 1.2, which requires specific forms of alternatives.

 *   Test, Sensory: If it is (1) a test or exercise that must be presented in non-text format<http://www.w3.org/WAI/GL/WCAG20/#must-nontextdef>, or (2) primarily intended to create a specific sensory experience<http://www.w3.org/WAI/GL/WCAG20/#sensoryexpdef>, then text alternatives at least provide descriptive identification of the non-text content.
 *   CAPTCHA<http://www.w3.org/WAI/GL/WCAG20/#CAPTCHAdef>: If it is to confirm that content is being accessed by a person rather than a computer, then text alternatives that identify and describe the purpose of the non-text content are provided, and alternative forms of CAPTCHA using output modes for different types of sensory perception are provided to accommodate different disabilities.
 *   Decoration, Formatting, Invisible: If it is pure decoration<http://www.w3.org/WAI/GL/WCAG20/#puredecdef>, or used only for visual formatting, or if it is not presented to users, then it is implemented in a way that it can be ignored by assistive technology<http://www.w3.org/WAI/GL/WCAG20/#atdef>.

Guideline 1.2 Media: Provide appropriate alternatives for media Understanding Guideline 1.2<http://www.w3.org/WAI/GL/WCAG20/WD-UNDERSTANDING-WCAG20-20071218/media-equiv.html>



1.2.1 Basic Media Alternative: A descriptive identification is provided for (1) synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef>, (2) [audio-only] content or (3) [video-only] content; and that content is [non-blocking]. (Level A) How to Meet 1.2.1 Understanding 1.2.1




1.2.2 Audio Description: Audio description<http://www.w3.org/WAI/GL/WCAG20/#audiodescdef> is provided for all [prerecorded] [video] content in synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef>. (Level AA) How to Meet 1.2.2 Understanding 1.2.2



1.2.3 Captions: Captions<http://www.w3.org/WAI/GL/WCAG20/#captionsdef> are provided for all [audio] content in synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef>. (Level AA) How to Meet 1.2.4 Understanding 1.2.3




1.2.4 Text Alternative: A text alternative<http://www.w3.org/WAI/GL/WCAG20/#text-altdef> that presents equivalent information of all [audio-only] content and all [video-only] content is provided (Level AAA) How to Meet 1.2.4 Understanding 1.2.4



1.2.5 Sign Language: Sign language interpretation<http://www.w3.org/WAI/GL/WCAG20/#sign-languageinterpdef> is provided for all [audio] content in synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef>. (Level AAA) How to Meet 1.2.5<http://www.w3.org/WAI/WCAG20/quickref/20071218/Overview.php#qr-media-equiv-sign> Understanding 1.2.5<http://www.w3.org/WAI/GL/WCAG20/WD-UNDERSTANDING-WCAG20-20071218/media-equiv-sign.html>



1.2.6 Audio Description (Extended): Extended audio description<http://www.w3.org/WAI/GL/WCAG20/#extended-addef> is provided for all [prerecorded] [video] content in synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef> (Level AAA) How to Meet 1.2.6<http://www.w3.org/WAI/WCAG20/quickref/20071218/Overview.php#qr-media-equiv-extended-ad> Understanding 1.2.6<http://www.w3.org/WAI/GL/WCAG20/WD-UNDERSTANDING-WCAG20-20071218/media-equiv-extended-ad.html>



1.2.7 Full Text Alternative: A full text alternative for synchronized media including any interaction <http://www.w3.org/WAI/GL/WCAG20/#fullmultaltdef> is provided for prerecorded synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef>. (Level AAA) How to Meet 1.2.7<http://www.w3.org/WAI/WCAG20/quickref/20071218/Overview.php#qr-media-equiv-text-doc> Understanding 1.2.7<http://www.w3.org/WAI/GL/WCAG20/WD-UNDERSTANDING-WCAG20-20071218/media-equiv-text-doc.html>


Definitions:

audio
the technology of sound reproduction
Note: audio can be created synthetically (including speech synthesis), or recorded from real world sounds, or both.

audio description

additional [audio] information that describes important visual details that cannot be understood from the main soundtrack alone

Note 1: Audio description of video provides information about actions, characters, scene changes, on-screen text, and other visual content.

Note 2: In standard audio description, narration is added during existing pauses in dialogue. (See also extended audio description<http://www.w3.org/WAI/GL/WCAG20/#extended-addef>.)

Note 3: Where all of the video information is already provided in existing audio, no additional audio description is necessary

Note 4: Also called "video description" and "descriptive narration."

audio-only

a time-based presentation that contains only [audio] (no [video] and no interaction)
video-only

a time-based presentation that contains only [video] (no [audio] and no interaction)
live
information captured from  a real world event and transmitted to the receiver within 30 seconds of the occurrence of the event
Note: If information is completely computer generated, it is not live.

pre-recorded: information that is not [live]


synchronized media

[audio] or [video] synchronized with another format for presenting information and/or with time-based interactive components, unless the media is an alternative to text<http://www.w3.org/WAI/GL/WCAG20/#multimedia-alt-textdef> which is clearly labeled as such

video
the technology of moving or sequenced pictures or images
Note: video can be made up of animated or photographic images, or both.

non-blocking content

content in a web page which is not used as the only means of conveying information needed to comprehend a web page or perform an action needed to operate a web page.


Sean Hayes
Incubation Lab
Accessibility Business Unit
Microsoft

Office:  +44 118 909 5867,
Mobile: +44 7875 091385
Received on Monday, 25 February 2008 20:21:57 GMT

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