- From: Wendy Chisholm <wendy@w3.org>
- Date: Wed, 10 Nov 2004 00:10:28 -0500
- To: wai-gl <w3c-wai-gl@w3.org>
- Message-ID: <4191A2C4.8000200@w3.org>
At the face-to-face I presented a proposal that combined Guideline 1.1
and Guideline 1.2 [1]. From that discussion, John Slatin and I took an
action item to separate the two such that 1.1 focuses on text
alternatives and 1.2 focuses on synchronized alternatives. The
following proposals are the results of these discussions (and also
available at [2]). While the proposals are not perfect, we hope that
they are a step forward and may be included in the next drafts for
public review and discussion. If adopted, this proposal should close
the list of 24 issues at the end of this email.
[1] <http://www.w3.org/2004/10/wcag-media-equiv2.html>
[2] <http://www.w3.org/2004/10/wcag-media-equiv3.html>
Guideline 1.1 Provide text alternatives for non-text content
Level 1
1. For all non-text content that is functional, such as graphical
links or buttons, text alternatives identify the purpose or function of
the non-text content.
2. For all non-text content that is used to convey information, text
alternatives convey the same information.
Note: for multimedia, this means transcripts are provided.
3. For non-text content that is intended to create a specific sensory
experience, such as music or visual art, text alternatives identify and
describe the non-text content.
4. [deleted]
5. Non-text content that does not provide information, functionality,
sensory experience, is marked such that it can be ignored by assistive
technology.
6. Any text alternatives provided are explicitly associated with
non-text content.
7. For live audio-only or live video-only content, such as internet
radio or webcams, text alternatives describe the purpose of the
presentation or alternative real-time content is linked to, such as
traffic reports for a traffic webcam
Note: real-time content does not imply real-time captions.
Ednote: This is similar to #1 above, yet it seems we need to
specifically address audio-only and video-only content to avoid confusion.
Level 2
Level 3
1. For multimedia content, a combined transcript of audio
descriptions and captions is provided.
Examples
Example 1: an image used as a button.
A magnifying glass icon is used to link to the search page of a Web
site. A screen reader identifies the button as a link and speaks the
text alternative, "Search."
Example 2: a data chart.
A bar chart compares how many widgets were sold in June, July, and
August. The short label says, "Figure one - Sales in June, July and
August." The longer description identifies the type of chart, provides a
high-level summary of the data comparable to that available from the
chart, and provides the data in a table.
Example 3: a recording of a speech.
The link to an audio clip says, "Chairman's speech to the assembly." A
link to a text transcript is provided immediately after the link to the
audio clip.
Example 4: a recording of a symphony.
The link to an audio file says, "Beethoven's 5th Symphony performed by
the Vienna Philharmonic Orchestra."
Example 5: an animation that illustrates how a car engine works.
An animation shows how a car engine works. There is no audio and the
animation is part of a tutorial that describes how an engine works. All
that is needed is a description of the image. From "How car engines
work: Internal combustion"
Ednote: Examples to be developed: a live radio stream and a live webcam.
Guideline 1.2 Provide synchronized alternatives for multimedia
Level 1
1. Captions are provided for prerecorded multimedia.
2. Audio descriptions are provided for prerecorded multimedia.
3. If multimedia content is rebroadcast from another medium, the
accessibility features required by policy for that medium are intact.
Ednote: Even though there are instances where captions and audio
descriptions are not required, this version of Guideline 1.2 does not
attempt to address the variations. Instead, it assumes more detail is
included in the techniques documents and that policy makers will clarify
when captions and audio descriptions are required.
Level 2
1. Real-time captions are provided for live multimedia.
Level 3
1. Sign language is provided for multimedia
2. Extended audio descriptions are provided for prerecorded multimedia.
3. Audio descriptions are provided for live multimedia Ednote: Audio
descriptions for live multimedia are rare. However, we wanted to
encourage the development of future techniques.
Examples
Example 1: a movie with audio description
Transcript of audio from the first few minutes of, "Teaching Evolution
Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky
Productions, Inc.)
Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." Now,
a teacher shows photographs.
Bonnie Chen: These are all shot at either the Everglades...for today you
just happen to be a species of wading bird that has a beak like this."
Describer: wooden tongue depressors
Example 2: a captioned tutorial
A video clip shows how to tie a knot. The captions read, "(music)
USING ROPE TO TIE KNOTS
WAS AN IMPORTANT SKILL
FOR THE LIKES OF SAILORS, SOLDIERS, AND WOODSMEN."
From Sample Transcript Formatting by Whit Anderson
Ednote: Examples to be developed: an animation with soundtrack of music
with lyrics, an interactive slideshow, an animation with musical soundtrack.
Definitions - to be included in the Glossary:
(didn't finish these)
video-only: @@clarify that it is not a Web page (to address issue 792)
audio description - Additional audio narration that explains important
details that cannot be understood from the main soundtrack alone. During
pauses in dialog, audio description provide information about actions,
characters, scene changes and on-screen text to people who are blind or
visually impaired.
extended audio descriptions...
captions - A synchronized transcript of dialogue and important sound
effects. Captions provide access to multimedia for people who are deaf
or hard of hearing.
multimedia - contains both audio and video
non-text content - @@
transcript - @@
====
Summary of issues for this guideline:
<http://www.w3.org/2004/10/wcag-media-equiv2.html#Issues>
24 Issues that could be closed if this proposal is adopted (some require
verification from the reviewer before closing):
171, 438, 668, 792, 445, 981, 1084, 446, 447, 477, 667, 793, 871, 980,
983 (if include suggestions in General Techniques), 1027, 1028, 1029,
1083, 1085, 1155, 1156, 1157, 1158
9 Issues that are not addressed: 555, 781, 792, 794, 952, 1151, 1152,
1153, 1154
--
wendy a chisholm
world wide web consortium
web accessibility initiative
http://www.w3.org/WAI/
/--
Received on Wednesday, 10 November 2004 05:10:35 UTC