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Suggested rewrite of 3.7 (Provide volume configuration)

From: Greg Lowney <gcl-0039@access-research.org>
Date: Thu, 07 Oct 2010 16:37:48 -0800
Message-ID: <4CAE67DC.7000108@access-research.org>
To: WAI-UA list <w3c-wai-ua@w3.org>
  Guideline 3.7 has a number of problems. It currently read:

    *Guideline 3.7 Provide volume configuration.***

    ***3.7.1 Global Volume:* The user can globally <http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100920/Overview.html#def-global-configuration> set volume of all audio tracks <http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100920/Overview.html#def-audio-track> it renders (including a "mute" setting) through available operating environment <http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100920/Overview.html#def-operating-environment> mechanisms. (Level A)

    *3.7.2 Speech Volume:* The user can adjust the volume of all audio tracks <http://www.w3.org/WAI/UA/2010/ED-IMPLEMENTING-UAAG20-20100920/#def-audio-track> the user agent renders, independently or relative to the volume level at the operating environment. (Level A)

Here's my suggested rewrite, which reduced two SC to one, followed by explanation:

    *Guideline 3.7 Provide volume control.***

    Upshot: Let users adjust the volume of each audio track relative to the system volume, but respect global mute settings by default (3.7.1).

    *3.7.1 Audio Volume Control:* The user can /independently/ adjust the volume of all audio tracks <http://www.w3.org/WAI/UA/2010/ED-IMPLEMENTING-UAAG20-20100920/#def-audio-track> the user agent renders, /relative /to the global volume level set through operating environment <http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100920/Overview.html#def-operating-environment> mechanisms. /However, the user agent should not override a global option that says audio should be muted unless this is optional, not enabled by default, and the user is cautioned as to its implications./ [Alternate wording: /However, if audio is muted as the global level the user agent should not override this unless the behavior is optional, not enabled by default, and the user is cautioned as to its implications.]/ (Level A)**


*1. The title is "Speech Volume" but the SC is about all sound*, not just speech. We should probably change the title to "Track Volume".

*2. The phrase "can adjust the volume...independently or relative to" is ambiguous *as to whether it means independently of other tracks or independently of the global volume level, AND as to whether the choice belongs to the user or the application; the former is the difference between absolute and relative volume control, the latter between requiring  the user be allowed to choose from both options (relative or absolute volume setting) and allowing the user agent can choose whether to provide either or both. Actually, I don't feel it necessary to require absolute volume control, and I'm not even sure many platforms support it, so I suggest only requiring per-track adjustment relative to the global volume level.

*3. 3.7.1 and 3.7.2 may conflict *if 3.7.2 is trying to require that the volume of tracks to be adjustable independently of the operating system's volume level, while 3.7.1 requires the user be able to set the global volume of all tracks through the operating system: essentially, 3.7.1 says the global setting should override local settings, while 3.7.2 says the opposite. To comply with both, the user would need to have an option on the global volume control of whether or not to allow individual applications to override the global volume setting.

*4. Local settings should not override global mute.* That is, saying that the application should let the user adjust per-track volume should not be taken as implying that the application should or even should be allowed to override a global mute setting. If the global setting says audio should be muted, the application should respect that, while if the global mute setting is not enabled that would /not /imply the application can't have its own mute setting. Basically, if either a platform or application mute settings are True, the application should make no sound regardless of any global and application volume settings. Similarly, either being set to False should not imply that sound is required.

The exception, though, is that I think it's acceptable for an application to ignore the global mute setting if this is not the default behavior, the user is warned that it will do so before making or confirming their choice, and the user also has the option to adjust local volume without overriding the global mute setting. For example, I would not object to an alarm clock application that provides a check box by which the user can say to play the alarm aloud even if the system is muted, provided the check box is normally unchecked and is accompanied by text cautioning the user about this behavior.

*5. One says "it" and the other says "the user agent"*, which should probably be made consistent.

*6. "Volume control" is a simpler phrase than "volume configuration" *yet means the same thing.

*7. "Volume" often refers to file systems*, as driven home when I tried doing Web searches on this topic, so saying "audio volume" is probably clearer.
*    Thanks,
Received on Thursday, 7 October 2010 23:39:41 UTC

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