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RE: Combing checkpoints 1.2 and 1.3

From: Charles McCathieNevile <charles@w3.org>
Date: Sat, 4 Aug 2001 04:48:23 -0400 (EDT)
To: Gregg Vanderheiden <gv@trace.wisc.edu>
cc: <w3c-wai-gl@w3.org>
Message-ID: <Pine.LNX.4.30.0108040438180.3450-100000@tux.w3.org>
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

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.



On Fri, 3 Aug 2001, Gregg Vanderheiden wrote:

  Ah in looking is see part of the problem for thinking 1.2 and 1.3 were
  the same

  in 1.2 it says

  "When text equivalents of visual information are spoken aloud (either by
  a human or a speech synthesizer) and synchronized with the multimedia
  presentation they are called "auditory descriptions." Refer to
  checkpoint 1.3. "

  This is inaccurate.   1.2 is only about text.  So it should read

  "When text equivalents of visual information are provided they must be
  synchronized with the multimedia presentation.   ( NOTE:  Checkpoint 1.3
  requires that audio descriptions also be provided until text
  descriptions can be read by screen readers (or equiv) in synchrony with
  the visual track.)

  Having posted the last two memos -- I would like to invite people to
  find a way to combine these two if we can -- since it would be nice to
  do so.   But 1.3 is so specialized it may be hard.     Give it a whirl



  -- ------------------------------
  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/>
  FAX 608/262-8848 
  For a list of our listserves send “lists” to listproc@trace.wisc.edu

  -----Original Message-----
  From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
  Behalf Of Gregg Vanderheiden
  Sent: Friday, August 03, 2001 9:50 PM
  To: w3c-wai-gl@w3.org
  Subject: RE: Combing checkpoints 1.2 and 1.3

  The only trouble is that the purpose of 1.3 was to require a description
  that could be audible-ized.    That is -- an audio description   (until
  the text equiv could be read by screen readers - in which case it would
  automatically fulfill this requirement).

  By combining these two -- we now require that the text version be
  synchronized but we do not require an audio version exist (though if you
  did one you would need to synchronize it).   In effect we would remove
  audio descriptions for movies from the guidelines.

  Now one could say that the criteria would add that back in.  But I don’t
  think we can have criteria for a point require something that is not
  covered by the point itself.

  We tried to fit 1.3 into 1.2 in the first place and were unable.  That
  is how we ended up with it as a separate item.   It still needs be
  separate unless we can figure out at way to specifically require this in
  the checkpoint -- which the current (revised) 1.2 does not


  -- ------------------------------
  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/>
  FAX 608/262-8848 
  For a list of our listserves send “lists” to listproc@trace.wisc.edu

  -----Original Message-----
  From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
  Behalf Of Anne Pemberton
  Sent: Friday, August 03, 2001 3:59 PM
  To: Wendy A Chisholm; w3c-wai-gl@w3.org
  Subject: Re: Combing checkpoints 1.2 and 1.3


           I've read the combined new 1.2 and it seems to cover everything

  that was covered before.  Go for it!


  At 01:20 PM 8/3/01 -0400, Wendy A Chisholm wrote:
  >The 26 July 2001 draft combined checkpoints 1.2 and 1.3 into one
  >Previous 1.2: Synchronize text equivalents with multimedia
  >Previous 1.3: Synchronize a description of the essential visual
  >information in multimedia presentations.
  >Proposed/current 1.2: 1.2 Synchronize media equivalents with
  >time-dependent presentations.
  >This change was made because it was proposed by Sean (13 January 2001)
  >and William (8 January 2001) [2] in separate threads. They received
  >support. The success criteria are similar, so they seemed to fit
  >well. Whether you synchronize a text-equivalent as an audio description
  >synchronize a recorded human voice - those seem to be techniques.
  >Should these be combined or should we keep them separate?
  >[1] http://lists.w3.org/Archives/Public/w3c-wai-gl/2001JanMar/0216.html
  >[2] http://lists.w3.org/Archives/Public/w3c-wai-gl/2001JanMar/0173.html
  >wendy a chisholm
  >world wide web consortium
  >web accessibility initiative
  >seattle, wa usa

  Anne Pemberton


Charles McCathieNevile    http://www.w3.org/People/Charles  phone: +61 409 134 136
W3C Web Accessibility Initiative     http://www.w3.org/WAI    fax: +1 617 258 5999
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Received on Saturday, 4 August 2001 04:48:24 UTC

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