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Proposal to delete checkpoint 3.2 and expand 4.10

From: Ian Jacobs <ij@w3.org>
Date: Fri, 09 Jun 2000 22:28:03 -0400
Message-ID: <3941A7B3.7DBAB180@w3.org>
To: w3c-wai-ua@w3.org

After several hours of discussions today with Charles
and Eric Hansen, I would like to propose the following 
changes to the document. The checkpoint numbers are those
of the 7 May Guidelines [1].

This proposal concerns "volume" related checkpoints. Here
are the checkpoints that include requirements for volume

3.2 Allow the user to turn on and off rendering of 
    background audio. [Priority 1] 
3.4 Allow the user to turn on and off rendering of 
    audio. [Priority 1] 
4.8 Allow the user to configure the audio volume. 
    [Priority 2] 
4.10 Allow the user to configure synthesized speech volume. 
    [Priority 1] 

At the 8 June teleconference, we resolved to change
the priority of 4.8 to P1.

I propose changing the requirements embodied by
these three checkpoints to the following:

 1) On/off control of global audio
    (When audio is a distraction. This is a special
     case of the second requirement, but can stand alone.)

 2) Control of global audio volume
    (For users who are hard of hearing and users for whom
     audio is a distraction.)

 3) Relative control of volume among audio objects.
    (Currently, this is only applied to the particular
     case of synthesized speech. For notes on discussion
     about this requirement, refer to 8 June minutes [2].)

Note that checkpoint 3.2 is about "background audio". What is the
difference between turning off background audio and turning
off audio, except when background audio is an identifiable track
that may be turned off independently of other audio? I'm not
sure there is a difference, but to capture the requirement
of being able to make background audio go away, I propose 
augmenting the scope of 4.10 to cover all audio objects.
Thus, we would end up with the following three priority
one checkpoints:

1) Allow the user to turn on and off rendering of audio.
2) Allow the user to configure the audio volume. 
3) Allow the user to control the volume of audio sources


1) The applicability clause is in effect here. Therefore,
   if some other agent renders the audio, that agent is
   responsible for volume control.

2) It might be possible to narrow the scope of checkpoint
   three to the two cases already discussed in the document:
   background audio and synthesized speech. However, defining
   "background audio" is difficult and I don't know whether
   life would be any easier on developers if we did. Does anyone
   know of existing software where the user can control the
   volume of different audio sources independently?
 - Ian

[1] http://www.w3.org/WAI/UA/WD-UAAG10-20000507
[2] http://lists.w3.org/Archives/Public/w3c-wai-ua/2000AprJun/0429.html

Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel:                         +1 831 457-2842
Cell:                        +1 917 450-8783
Received on Friday, 9 June 2000 22:28:07 UTC

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