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Proposed reorganisation of media accessibility (Issue 2393)

From: Sean Hayes <Sean.Hayes@microsoft.com>
Date: Mon, 25 Feb 2008 18:22:33 +0000
To: WCAG <w3c-wai-gl@w3.org>
Message-ID: <90EEC9D914694641A8358AA190DACB3D1B498C9C96@EA-EXMSG-C334.europe.corp.microsoft.com>
As discussed on the last telecom, here is my proposed reworking of the media accessibility requirements to somewhat untangle the logic. In this note I have attempted to preserve exactly the spirit and requirements of the current draft; so if you spot something that appears different it's probably an error. I have however adjusted slightly the specifics of prerecorded and live within synchronized media, so as to allow mixing these within one media package.

In the current draft, at level A the options for synchronised media appear to be, based on 1.1.1, 1.2.1 & 1.2.2
Notes:
I'm assuming that the 'at least provide' language in 1.1.1 is intended to apply to (1), (2), (3) and (4) in the Media, Test, Sensory exception, and that the 'or' in 1.2.2 is not an exclusive or (which would make for a weird interaction with level AA)


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

At level AA the options are:

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

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

In my reformulation, I have tried to bring these choices out a little more clearly. I have used slightly different definitions, and provided tentative (actual as opposed to circular) definitions for live and prerecorded, (the 30 second requirement for live is a SWAG in order to preserve testability, but I think the principle is OK).

NB: One trick I have pulled here in order to prevent the media alternative to text exception cropping up everywhere, is to move that exception into the definition of synchronised media, this greatly simplifies the other provisions but I'm not really happy with it. A better option would be to put the exception on Guideline 1.2, but I'm not sure if we can do that.








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 of [live] [audio-only] or [live] [video-only] content is provided; or a [text alternative] that presents equivalent information of [prerecorded] [audio-only] or [prerecorded] [video-only] content is provided. (Level A) How to Meet 1.2.1 Understanding 1.2.1

Note: If the media is an alternative to text<http://www.w3.org/WAI/GL/WCAG20/#multimedia-alt-textdef> and is clearly labeled as such, then 1.2.1 is met.



1.2.2 Synchronized Media Identification: A descriptive identification is provided for synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef>, (Level A) How to Meet 1.2.2 Understanding 1.2.2



1.2.3 Synchronized Media 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>; or 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 A) How to Meet 1.2.3 Understanding 1.2.3



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







1.2.5 Captions (Live): Captions<http://www.w3.org/WAI/GL/WCAG20/#captionsdef> are provided for all [live] [audio] content in synchronized media<http://www.w3.org/WAI/GL/WCAG20/#synchronizedmediadef>. (Level AA) How to Meet 1.2.3<http://www.w3.org/WAI/WCAG20/quickref/20071218/Overview.php#qr-media-equiv-real-time-captions> Understanding 1.2.3<http://www.w3.org/WAI/GL/WCAG20/WD-UNDERSTANDING-WCAG20-20071218/media-equiv-real-time-captions.html>



1.2.6 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 1.2.4<http://www.w3.org/WAI/WCAG20/quickref/20071218/Overview.php#qr-media-equiv-audio-desc-only> Understanding 1.2.4<http://www.w3.org/WAI/GL/WCAG20/WD-UNDERSTANDING-WCAG20-20071218/media-equiv-audio-desc-only.html>





1.2.7 Live Audio-only Alternative: A text alternative<http://www.w3.org/WAI/GL/WCAG20/#text-altdef> that presents equivalent information of [live] [audio-only] content is provided (Level AAA) How to Meet 1.2.2 Understanding 1.2.2



1.2.8 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>



1.2.9 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>



1.2.10 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

narration added to the soundtrack to describe 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.


Sean Hayes
Incubation Lab
Accessibility Business Unit
Microsoft

Office:  +44 118 909 5867,
Mobile: +44 7875 091385
Received on Monday, 25 February 2008 18:23:05 GMT

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