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Re: Comments from PFWG on CSS3 Speech Module

From: Daniel Weck <daniel.weck@gmail.com>
Date: Sun, 16 Oct 2011 23:50:53 +0100
Cc: www-style@w3.org, Bert Bos <bert@w3.org>, List WAI Liaison <wai-liaison@w3.org>, List WAI PF <w3c-wai-pf@w3.org>
Message-Id: <E03369D1-F455-429C-8B65-7AB3FD66022D@gmail.com>
To: Janina Sajka <janina@rednote.net>

Although the "louder" and "softer" keywords could be defined as corresponding decibel offsets, I would prefer to keep the current simple syntax, not only because it matches the SSML model, but also because of the particular significance of the existing, similar-sounding keywords (which are mapped to user-controlled parameters instead of fixed values). Note that there is already an informative paragraph describing the effect of +/- 6dB in layman terms, to make it simpler for authors to work-out effects such as "louder" or "softer" by using decibel offsets.

Regarding the potentiality of highly-contrasted content: as with any presentational features, authors may indeed produce horrible mixes of font size, colors, animations, etc. I am afraid that a technical specification cannot enforce good authoring practices. As for making recommendations, I think that this is out-of-scope as far as the CSS Speech Module is concerned. Doesn't this fit within the realm of WCAG? (I also suggested a W3C Community Group in previous emails, to kick-start the development of cross-format content and user-agent guidelines)

Your last concern is, I believe, already addressed by the current specification: the volume keywords map to actual values that are defined by the user, or at least by the default user-agent configuration. This is why the dynamic range is configurable as per the listener's environment (as described in the informative paragraph).

Please let us know whether this answer is satisfactory.
Many thanks!
Regards, Daniel

On 11 Oct 2011, at 20:25, Janina Sajka wrote:
> 1.)	voice-volume:
> There would seem to be a need for a relative value from current setting. |
> Louder / Softer.
> There exists the possibility of damaging content to be created.  Imagine a web
> page where it is very soft, and then in the middle the maximum decibels are
> shouted. | Deliberate suffering could be created, not unlike deliberately
> creating a photosentive epileptic situation. | Should this be prevented?
> This property is of concern because it appears to allow page
> authors to hijack the user interface. Screen reader users tend to set their
> speech volume at an audible, but comfortable level, and allowing an author to
> set the volume to x-loud or a high decibel could be a very disruptive
> experience. Furthermore, some screen reader users also have hearing
> impairments, so allowing an author to set the volume to x-soft or a low decibel
> could result in content being inaccessible to those users. We would like to
> suggest the group reconsider or further explain the necessity for this
> property, or at least consider removing the x-* values and decibel support. The
> spec's note ("listening environment and personal user preferences") at the end
> of this section appears to confirm our concern that this property is perhaps
> immature, and it would be unwise to implement this without additional
> consideration of other vague, unspecified details such as user preference
> overrides, and the ability for user agents to be more aware of their usage
> environment or context.
Received on Sunday, 16 October 2011 22:51:43 UTC

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