W3C CSS2 Cascading Style Sheets, level 2 - instructional media + ...

spatial audio), and paragraphs of class "peter" from the right. Paragraphs with
class "goat" will be very soft.
19.2 Volume properties: ’volume’
’volume’
Value: | | silent | x-soft | soft | medium | loud
| x-loud | inherit
Initial: medium
Applies to: all elements
Inherited: yes
Percentages: refer to inherited value
Media: aural
Volume refers to the median volume of the waveform. In other words, a highly
inflected voice at a volume of 50 might peak well above that. The overall values
are likely to be human adjustable for comfort, for example with a physical volume
control (which would increase both the 0 and 100 values proportionately); what
this property does is adjust the dynamic range.
Values have the following meanings:
Any number between ’0’ and ’100’. ’0’ represents the minimum audible
volume level and 100 corresponds to the maximum comfortable level.
Percentage values are calculated relative to the inherited value, and are
then clipped to the range ’0’ to ’100’.
silent
No sound at all. The value ’0’ does not mean the same as ’silent’.
x-soft
Same as ’0’.
soft
Same as ’25’.
medium
Same as ’50’.
loud
Same as ’75’.
x-loud
Same as ’100’.
User agents should allow the values corresponding to ’0’ and ’100’ to be set by
the listener. No one setting is universally applicable; suitable values depend on
the equipment in use (speakers, headphones), the environment (in car, home
theater, library) and personal preferences. Some examples:
A browser for in-car use has a setting for when there is lots of background
noise. ’0’ would map to a fairly high level and ’100’ to a quite high level. The
speech is easily audible over the road noise but the overall dynamic range is
compressed. Cars with better insulation might allow a wider dynamic range.
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