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Correction - proposal for issue 286 [Was Re: New proposal for issue 287 (volume control)]

From: Ian Jacobs <ij@w3.org>
Date: Mon, 03 Jul 2000 18:59:10 -0400
Message-ID: <39611ABE.8A8BE2E6@w3.org>
To: w3c-wai-ua@w3.org
Whoops! My apologies: 

 - Issue 287 is about on/off control of multimedia, blink, animations.
   This is still open.

 - Issue 286 is about volumes and was recorded as resolve at the
   22 June teleconf.
   http://cmos-eng.rehab.uiuc.edu/ua-issues/issues-linear.html#286

 - Ian

Ian Jacobs wrote:
> 
> Hello,
> 
> Today, Jon and I discussed issue 287 (about audio volume
> checkpoints) [1] (refer to resolution to keep one checkpoint
> about global control and one about independent control of
> audio sources [2]). Jon made the following comments:
> 
> 1) Independent control of audio volume is more important
>    for synchronized presentations than for non-synchronized
>    content. When content is not intended to be synchronized,
>    users don't need to worry about competing volumes as long
>    as they can play the sources independently. Global volume
>    control suffices when you can play different audio sources
>    independently. This is covered by the checkpoint to
>    start, pause, resume, etc. audio.
> 
> 2) Speech synthesizer volume is generally handled globally
>    for applications, not on an application-by-application
>    basis.
> 
> 3) "Too much control" (namely, the ability to change the
>    volume of independent audio sources played simultaneously)
> 
>    may require such complex interaction as not to promote
>    accessibility in practice. Are we requiring midi user agents
>    to provide an interface to control the volume of each track?
>    An equalizer tool (fairly comment to control relative volumes)
>    does not typically work on individual components but on
>    frequencies. Would that meet the requirements of this checkpoint
>    nonetheless?
> 
> 4) This is a fairly serious change of scope from the
>    previous checkpoints about volume.
> 
> 5) This discussion suggests a content issue: should the WCAG
>    be recommending that authors provide content in recognizable
>    tracks (e.g., a SMIL presentation) as opposed to formats
>    without tracks (e.g., a WAV file)?
> 
> Based on these comments, I'd like to propose that we reconsider
> the resolution. I have the following wording for the proposed
> checkpoint (proposed, but in no document yet):
> 
>    "Allow the user to control independently the volumes of
>     audio sources recognized as distinct."
> 
> I propose we create two checkpoints instead to emphasize
> the critical cases and to reduce the scope of the
> change:
> 
> <NEW 1>
>    "Allow the user to control independently the volumes
>     of audio sources synchronized to play simultaneously.
> </NEW 1>
> 
> <NEW 2>
>    "Allow the user to control the synthesized speech volume
>     independently of other sources of audio."
>        Note: It is expected that speech synthesizer volume will
>              be set at the system level.
> </NEW 2>
> 
> Notes:
> 
>  - The second checkpoint is much closer in scope to the
>    previous version of the speech volume checkpoint. For
>    example, from the Candidate Recommendation:
> 
>      "Allow the user to configure synthesized speech volume."
> 
>    However, the new version talks about control and not
>    just configuration.
> 
>  - As usual, if the UA cannot determine that two sources of
>    audio should be played simultaneously, the first
>    checkpoint does not apply.
> 
> Comments welcome,
> 
>  - Ian
> 
> [1] http://cmos-eng.rehab.uiuc.edu/ua-issues/issues-linear.html#287
> [2] http://lists.w3.org/Archives/Public/w3c-wai-ua/2000AprJun/0506.html
> 
> --
> Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
> Tel:                         +1 831 457-2842
> Cell:                        +1 917 450-8783

-- 
Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel:                         +1 831 457-2842
Cell:                        +1 917 450-8783
Received on Monday, 3 July 2000 18:59:13 GMT

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