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Re: [css3-speech] voice-volume

From: Daniel Weck <daniel.weck@gmail.com>
Date: Wed, 11 May 2011 18:57:48 +0100
Cc: W3C style mailing list <www-style@w3.org>
Message-Id: <F675F2D1-0C2E-4D69-9C3A-DB1225B0D627@gmail.com>
To: fantasai <fantasai.lists@inkedblade.net>

On 11 May 2011, at 18:18, fantasai wrote:
>
>>> x-soft
>>> The minimum audible level. Equivalent to '0'.
>>> soft
>>> Equivalent to '25'.
>>> medium
>>> The listener's preferred volume level. Equivalent to '50'.
>>> loud
>>> Equivalent to '75'.
>>> x-loud
>>> The maximum tolerable level. Equivalent to '100'.
>>
>> 'x-soft' must correspond to 'silent' when expressed on the "linear"  
>> scale,
>> so your suggestion doesn't work.
>
> I don't think 'linear' should be combinable with the keywords. It does
> not afford the author any extra capability, and it confuses the  
> meaning
> of the keywords.

Errr, my brain cells must have been damaged when I cross-read CSS 2.1  
Aural Stylesheets (which describes x-soft as '0') and SSML 1.0 (which  
doesn't).
My bad. I'll get back to the list with updated prose, in sync with  
SSML 1.1.

>> http://www.w3.org/TR/CSS21/aural.html#propdef-volume
>>
>> Could you please point to a CSS 2 property definition that  
>> exemplifies good editorial practice? Thanks.
>
> Like the propdef-volume link you have there?

Oh I see, you meant the Aural Appendix (I thought you were referring  
to some other normative sections of CSS21).

>> The "relative" keyword is mandatory for pitch values expressed in  
>> Hz or semitone units. Would you advice to break down
>> <relative-change> into separate fields, and to allow the keyword on  
>> either left or right of the actual numerical value ?
>>
>> http://dev.w3.org/csswg/css3-speech/#voice-pitch
>
> Yes.

Ok.

>>> For cues, do we really need 'silent'? Why wouldn't the author just  
>>> remove the
>>> cue, replacing with a rest if necessary?
>>
>> User stylesheets must be able to silence audio cues with "! 
>> important" rules. I agree that the use-case is limited (one would
>> normally specify "none" to completely remove a cue), but we need to  
>> be consistent with voice volume.
>
> I'm not convinced of this use case. Do we really have users who would
> rather silence a cue than remove it?

Well, SSML eloquently states:

---
"silent", the contained text is read silently;
---

When this "silencing" logic is applied to spoken text via the main  
'voice-volume' control, it affects the volume level in the aural box  
model as a whole. As a result, prerecorded audio cues "automatically"  
get silenced, as their volume is expressed relatively.

Arguably, this isn't motivated by any tangible use-case, it just  
happens to be possible to set the volume level to "silent" (or "0%",  
or "-INFINITY dB", conceptually), which doesn't alter the playback  
duration, just the audio output. I don't know a use-case for this, but  
it is doable.

Similarly, I admit that I am not aware of a use-case for "silencing"  
audio cues independently from the spoken text of the selected element,  
but that doesn't mean that we should prevent it. In fact I'd rather be  
consistent with 'voice-volume' (otherwise we should remove "silent"  
from there too, as it is equivalent to "0%" in SSML 1.0 or "- 
LARGE_NUMBER dB" in SSML 1.1).

Dan
Received on Wednesday, 11 May 2011 18:03:41 GMT

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