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From: Jim Allan <jimallan@tsbvi.edu>
Date: Thu, 28 Oct 2010 10:55:42 -0500
Message-ID: <AANLkTi=v1VDVUyqVqiTYWmPVbRaVWbU0DhCUXBgrAmd-@mail.gmail.com>
To: WAI-ua <w3c-wai-ua@w3.org>
jallan to discuss EVD2 & 3 - add to IER to 4.9 SC or create new SC,
also review CC2,3,4

This action was on Mark and myself. We were joined by Greg L. in
crafting ideas and responses.

(EVD-2) 	Support automatically pausing the video and main audio tracks
in order to play a lengthy description.
(EVD-3) 	Support resuming playback of video and main audio tracks when
the description is finished.

There is no standard way to automatically pause the main video and
play the extended audio track and then restart the video (essentially,
have the audio timeline control the video track). There are ways to
mark up this kind of behavior in SMIL. However, there is no current
player that will handle the markup.
There are no good functional examples. NCAM has examples but they are
mock ups, simulating the pausing of the movie to play the Extended
Description (ED). In NCAM's demonstration the user must select an
alternate movie that has the pauses for ED built in.
WCAG20 has AA requirement for authors to accommodate this needed
functionality for users.
UAAG20 states users are able to select tracks and alternate tracks.
The user can select the extended description track if provided by the
It is not the UAWGs place to make new standards. UAAG20 will need 2
implementations for each SC. We don't see this feature being added in
the near future (before we reach last call)

add ED information to 4.9.8 track manipulation - Intent/Example/Resources
add to IER, use case - author created the ED as a separate track, then
user can select the ED track.

4.9.8 Track Enable/Disable of Time-Based Media: During time-based
media playback, the user can determine which tracks are available and
select or deselect tracks. These selections may override global
default settings for captions, audio descriptions, etc.

Authors are able to create time-based media with video (perhaps
multiple video tracks), multiple audio tracks ( e.g. different
languages, video description, extended video description), and
multiple caption tracks (e.g. different languages, text of video
description, text of extended video description). Users should be able
to identify and select from the available tracks. The user may also
change their selections. The user agent must provide a mechanism to
list the available author supplied tracks and allow the user to select
which to play.

Jose, a student with a hearing disability, sometimes misses parts of
the dialog in movies because of the sound level or background noise.
He can select the caption track to read the dialog and not miss

Lin, who is blind, cannot see all of the action in suspense movies.
She can select the video description track in addition to the audio
track, to hear the action and scenes described during the movie and
not miss out on the suspense.

Mary has an learning and attention problem. She needs more elaborate
descriptions of what is happening in a movie of a science
demonstration. The author provided extended descriptions for specific
concepts. When Mary selects the extended descriptions the video
pauses, while extra audio information about the concept is presented.
The author also provided a caption track to go along with the extended
descriptions so Mary can read along with the audio and focus on
reading and listening to the content.

HTML 5 Video Element http://www.w3.org/TR/html5/video.html#video

Jim Allan, Accessibility Coordinator & Webmaster

Texas School for the Blind and Visually Impaired

1100 W. 45th St., Austin, Texas 78756

voice 512.206.9315    fax: 512.206.9264  http://www.tsbvi.edu/

"We shape our tools and thereafter our tools shape us." McLuhan, 1964
Received on Thursday, 28 October 2010 15:56:12 UTC

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