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RE: Combing checkpoints 1.2 and 1.3

From: Gregg Vanderheiden <gv@trace.wisc.edu>
Date: Sat, 4 Aug 2001 13:14:25 -0500
To: "'Charles McCathieNevile'" <charles@w3.org>
Cc: <w3c-wai-gl@w3.org>
Message-ID: <002b01c11d11$4b5fbea0$066fa8c0@750>
Requiring multiple forms of information is very different than requiring
that information be in a form that can be rendered in different forms.

1.1. and 3.4 are fundamentally different in this respect.

I do not think we should combine them.



RE 1.2 and 1.3 --- the problem is again that 1.3 is the only place audio
description is required.

Gregg


-- ------------------------------
Gregg C Vanderheiden Ph.D.
Professor - Human Factors
Dept of Ind. Engr. - U of Wis.
Director - Trace R & D Center
Gv@trace.wisc.edu <mailto:Gv@trace.wisc.edu>, <http://trace.wisc.edu/>
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-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
Behalf Of Charles McCathieNevile
Sent: Saturday, August 04, 2001 3:48 AM
To: Gregg Vanderheiden
Cc: w3c-wai-gl@w3.org
Subject: RE: Combing checkpoints 1.2 and 1.3

I think there are two seperate axes here.

One is that we need various kinds of equivalent content - 1.1 talks
about
text, 1.3 talked about audio, 3.4 talks about audio, graphics, video,
and so
on.

The other is that for dynamic content it is important that the
equivalents
are synchronised. The highlight that follows the text as it is read
aloud,
the audio description that needs to match the dialogue, the captions
that
need to be assigned to the speakers and not a speaker or two later.

In WCAG 1.0 we had a general checkpoint requiring that dynamic content
had
equivalents that maintained synch, and the specific one for audio
equivalents
of video presentation. I think we can easily have just one checkpoint on
synching stuff. Not only is it a fairly one-dimensional topic (although
I am
well aware there is a huge amount in it - having to read SMIL 2.0 on
synchronisation parameters, tolerances and error recovery techniques
makes
that clear), but there is even an XML language produced by W3C (SMIL)
that
deals with it almost exclusively, and explaining the basic principle to
people takes very little time:

Make sure that things happen together if they are different ways of
showing
part of the same thing. Otherwise it gets confusing.

So I think it makes sense to put all the synching stuff from 1.2 and 1.3
into
one checkpoint.

Which leaves us with several requirements about equivalence - currently
we
have 1.1 for text equivalents, 3.4 for other media equivalents to text,
and
the existing single case of audio equivalents for video looking for a
home.

I think we can look again at Paul's proposal to combine 1.1 and 3.4 as
general requirement for equivcalent versions, and add audio description
of
video as a success criteria. I realise that we don't yet end up with a
perfect checkpoint, and that we could get a lot of success criteria, but
starting to enumerate all the different ones for what is essentially the
same
requirement, and work out what things are not useful success criteria,
would
be a step forward.

cheers

Charles
Received on Saturday, 4 August 2001 14:21:07 GMT

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