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Draft for UA Techniques 7.3 SMIL

From: Marja-Riitta Koivunen <marja@w3.org>
Date: Wed, 10 Mar 1999 10:23:16 -0500
Message-Id: <>
To: w3c-wai-ua@w3.org
Cc: ian@w3.org
Here is the first draft for 7.3. As you see there are still some questions
in the actual SMIL document that need  to be clarified.

7.3 SMIL

Support accessibility features defined by W3C Recommendations for SMIL.
Accessible presentation means here that the information can be easily
accessed by using different media and that the user can easily control
whether to show the information or not.

- Support accessible presentation of "title", "abstract" and "author"
attributes defined for SMIL synchronization elements.

- Support accessible presentation of "alt", "londesc", "title", "abstract"
and "author" attributes defined for SMIL media object elements.
!!The relationships between abstract and longdesc and alt should be clarified.

- Support an interface for turning captions on and off. Captions are
defined either by using "system-overdub-or-caption" attribute with value
"caption" or "system-captions" attribute with value "on". If
"system-captions" attribute has value "off" then what?

!!The captions are never shown? The captions are not shown initially? Or
should this just be deprecated and if really needed use stylesheets with
display=none? Overall, this is not very intuitive.

- Support an interface for turning overdubs on and off. Overdubs are
defined by using "system-overdub-or-caption" attribute with value "overdub".

- When captions are shown support a caption region.  According to user
preferences this could be embedded in the SMIL layout or shown in a
separate window.

- When user prefers to, support a stable, time independent view to the
links so that time dependent links can be easily searched.

- Offer a way to change system values affecting to "system-bitrate",
"system-screen-size" and "system-depth" attributes since these can have an
affect to the user interface. In addition, give feedback of the values in a
form that list only those selections that can have an effect to the user
interface. For instance, if the SMIL author has defined three different
user interfaces for bitrates below 1200, between 1200 and 2400, and over
24000 the user should be given a selection of these three choices not just
any bitrate number.

!!Another thing is how good it is to hardwire these UI choices to the
actual SMIL code and what choices need to be hardwired. It should be
possible to easily define UI changes tailored  for different devices and
systems also later.
Received on Wednesday, 10 March 1999 10:21:46 UTC

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