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Re: Resolution of Issue PR#285 on audio volume control

From: Charles McCathieNevile <charles@w3.org>
Date: Wed, 7 Jun 2000 07:54:11 -0400 (EDT)
To: "Gregory J. Rosmaita" <unagi69@concentric.net>
cc: Jon Gunderson <jongund@uiuc.edu>, User Agent Guidelines Emailing List <w3c-wai-ua@w3.org>
Message-ID: <Pine.LNX.4.20.0006070749380.27992-100000@tux.w3.org>
I would advance the same argument as Gregory. I think the requirement is to
be able to individually control the volume of each sound source - whatever it
is. Whether this is satisfied by the user agent or underlying system is
immaterial, but in practical terms I suspect that User agents are not always
easily able to expose multiple sources to the underlying system for
individual control.

Note also that synthesised speech is not necessarily the only form of audio
content that is important - for users with visual, cognitive, and hearing
disabilities there may be several types of audio running (music, synthesised
speech for text content, spoken content such as audio descriptions, etc) and
being able to distinguish what is going on in each channel (for example by
playing one speech channel at a time) is the difference between having access
and not. Just think of a teleconference where several people are speaking -
our volume control is the chair...


Charles McCN

On Wed, 7 Jun 2000, Gregory J. Rosmaita wrote:

  Jon wrote
  I encourage people to present arguments on changing checkpoint 4.8 from P2 
  to P1.
  aloha, jon!
  the argument is quite simple...   there are many instances when i need 
  synthesized speech at a certain level--which i can control on-the-fly 
  thanks to the P1 requirement, if the wording of 4.10 is restored from 
  "configure" to "control"--and the audio to play at a different level, in 
  order that i can clearly and distinctly hear the 2 simultaneously...
  if i can't hear the synthesized speech because i can't adjust the volume of 
  the audio source as it is playing, save by recourse to the OS' native 
  volume control interface, i may have already missed out on what i needed to 
  hear -- the synthesized content in conjunction with the audio -- especially 
  if the audio is being streamed...  it's akin to reading a page while 
  looking at the illustrations with your peripheral vision, or the type of 
  integration of textual and non-textual content one's brain makes to give 
  one the gestalt view of the page when it is perceived in screenfulls, so i 
  vote to raise 4.8 from P2 to P1

Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
W3C Web Accessibility Initiative                      http://www.w3.org/WAI
Location: I-cubed, 110 Victoria Street, Carlton VIC 3053
Postal: GPO Box 2476V, Melbourne 3001,  Australia 
Received on Wednesday, 7 June 2000 07:54:14 UTC

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