Checkpoint 1.2 Proposal for Review

The following edits to checkpoint 1.2 are based on a number of comments,
proposals and responses that were originally posted to the list in December
2002. The threads related to this checkpoint begin at
http://lists.w3.org/Archives/Public/w3c-wai-gl/2002OctDec/0233.html and
include the proposal numbers referenced in the list of changes below.

List of Changes:

* removed the third level 2 success criterion "if Web content is an
interactive audio-only presentation, the user is provided with the ability
to view only the captions, the captions with the audio, or both together"
per Andi's proposal
(http://lists.w3.org/Archives/Public/w3c-wai-gl/2002OctDec/0249.html)
[Proposal #5]
* removed the second level 2 success criterion, "captions and Audio
descriptions are provided for all live broadcasts that are professionally
produced" per a suggestion from Charles
(http://lists.w3.org/Archives/Public/w3c-wai-gl/2002OctDec/0286.html).
[proposal #8]
* reworded the first success criterion at the minimum level per John, Gregg
and Lee's comments. [proposal #1]
* reworded the exception about real-time, audio-only content (second success
criteria under minimum level) [proposal #2]
* added Andi's proposed level 3 success criterion [proposal #3]
* added John's rewording of definition of audio presentation [proposal #4]
with GV's note
(http://lists.w3.org/Archives/Public/w3c-wai-gl/2002OctDec/0242.html)
* added John's revised note regarding single-sense simultaneous actions with
GV's suggested rewording
(http://lists.w3.org/Archives/Public/w3c-wai-gl/2002OctDec/0242.html) to the
benefits section [proposal #5]
* reworded minimum level success criterion 5 [proposal #10]
* incorporated various editorial suggestions from John
(http://lists.w3.org/Archives/Public/w3c-wai-gl/2002OctDec/0284.html).
[Proposal #1, #3, #8, #9]

Here are the proposed changes to this checkpoint for review:

Checkpoint 1.2 Provide synchronized media equivalents for time-dependent
presentations.

Success criteria

You will have successfully met Checkpoint 1.2 at the Minimum Level if:

    1. an audio description is provided of all significant visual 
       information in scenes, actions and events that cannot be perceived
       from the sound track alone.
		+ Note: When adding audio description to existing materials,
the
              amount of information conveyed through audio description is
              constrained by the amount of space available in the
              existing audio track.  It may also be impossible or  
              inappropriate to freeze the  audio/visual program to insert
              additional audio description.
    2. all significant dialogue and sounds are captioned
       exception: If the Web content is real-time and audio-only and not 
       time-sensitive and not interactive a transcript or other non-audio
       equivalent is sufficient.
    3. descriptions and captions are synchronized with the events they
       represent.
    4. if the Web content is real-time video with audio, real-time
       captions are provided unless the content:
          + is a music program that is primarily non-vocal
    5. If the Web content is real-time non-interactive video (e.g., a Webcam

       of ambient conditions), either provide an equivalent that conforms to

       checkpoint 1.1 (e.g., an ongoing update of weather conditions) or 
       link to an equivalent that conforms to checkpoint 1.1 (e.g., a link 
       to a weather Web site).
    6. if a pure audio or pure video presentation requires a user to
       respond interactively at specific times in the presentation, then
       a time-synchronized equivalent (audio, visual or text)
       presentation is provided.
   exception: if content is rebroadcast from another medium or resource
   that complies to broadcast requirements for accessibility (independent
   of these guidelines), the rebroadcast satisfies the checkpoint if it
   complies with the other guidelines.

You will have successfully met Checkpoint 1.2 at Level 2 if:

    1. the audio description has been reviewed and is believed to include
       all significant visual information in scenes, actions and events
       (that can't be perceived from the sound track) to the extent
       possible given the constraints posed by the existing audio track
       (and constraints on freezing the audio/visual program to insert
       additional auditory description).

You will have successfully met Checkpoint 1.2 at Level 3 if:

    1. provide a text document that merges all audio descriptions and 
       captions into a collated script (which provides dialog, important 
       sounds and important visual information in a single text document).
    2. captions and Audio descriptions are provided for all live
       broadcasts which provide the same information.
    3. The presentation does not require the user to read captions and 
       the visual presentation simultaneously in order to understand the 
       content.

The following are additional ideas for enhancing a site along this
particular dimension:
     * (presently no additional criteria for this level.)

Definitions (informative)

   A time-dependent presentation is a presentation which
     * is composed of synchronized audio and visual tracks (e.g., a
       movie), OR
     * requires the user to respond interactively at specific times in
       the presentation.

   Media equivalents present essential audio information visually
   (captions) and essential video information auditorily (audio
   descriptions).
     * captions are text equivalents of auditory information from speech,
       sound effects, and ambient sounds that are synchronized with the
       multimedia presentation.
     * audio descriptions are equivalents of visual information from 
       actions, body language, graphics, and scene changes.  Audio
       descriptions are voiced (either by a human or a speech 
       synthesizer) and synchronized with the multimedia presentation.

Benefits (informative)

     * People who are deaf or have a hearing loss can access the auditory
       information through the captions.
     * People who are blind or have low vision as well as those with
       cognitive disabilities who have difficulty interpreting visually
       what is happening benefit from the audio descriptions of the
       visual information.

   People without disabilities also benefit from the media equivalents.

     * People in noisy environments or with muted sound often use
       captions.
     * Captions are used by many to develop language and reading skills.
     * Audio descriptions also provide visual information for people who
       are temporarily looking away from the video presentation such as
       when following an instructional video and looking at their hands.
     * Captions and text descriptions can also be used to index and
       search media files.

Note: Time-dependent presentations requiring people to use a single sense 
to follow two or more things at the same time may present significant 
barriers to some users. Depending on the nature of the of presentation, it 
may be possible to avoid scenarios where, for example, a deaf user would be 
required to watch an action on the screen and read the captions at the same 
time. However, this would not be achievable for live broadcasts (e.g. a 
football game). Where possible, provide content so that it does not require 
tracking multiple simultaneous events with the same sense, or give the user 
the ability to freeze the video so that captions can be read without missing

the video.

Examples (informative)

     * Example 1: a movie clip with audio description and captions.
       A clip from a movie is published on a Web site. In the clip, a
       child is trying to lure a puppy to the child's bedroom by laying a
       trail of crumbs. The child mumbles inaudibly to himself as he lays
       the trail. When not watching the video, it is not obvious that he
       is laying a trail of crumbs since all you hear is the mumbling.
       The audio description that is interspersed with the child's
       mumbling says "Charlie lays a crumb on each stair leading to his
       room." The caption that appears as he mumbles is, "[inaudible
       mumbling]."
     * Example 2: a video clip of a news story.
       A video clip accompanies a news story about the recent flooding in
       a major city. The reporter describes what is seen, for everyone.
       No audio description is necessary. The captions display what the
       reporter is saying.
     * Example 3: a silent animation.
       An animation shows a pantomime climbing a ladder. There is no
       audio track for this animation. No captions or audio description
       are required. Instead, a text equivalent is provided as described
       in checkpoint 1.1.

--
Ben Caldwell | caldwell@trace.wisc.edu
Trace Research and Development Center (http://trace.wisc.edu)

Received on Tuesday, 15 April 2003 11:57:26 UTC