2010/2/18 Lennart Poettering <mznyfn@xxxxxxxxxxx>
> On Thu, 18.02.10 09:48, Raymond Yau (superquad.vortex2@xxxxxxxxx) wrote:
>
> > From the viewpoint of user, they only care how easy to find the point
> which
> > is no software gain or software auttentation since software gain lead to
> > clipping
>
> We decided to expose software amplification in the UI, since it is
> actually a much requested feature, and I have used myself a couple of
> times.
>
> The primary use case is when you play a DVD (which very often has
> audio normalized to a very low volume) on weak speakers, such as
> laptop speakers.
>
> Lennart
>
> --
>
There are many mixer switch need to export to the mixer control
some are hardware specific and some are AC 97 standard feature which affect
the dB volume
e.g. ac97 standard external amplifier
control.52 {
comment.access 'read write'
comment.type BOOLEAN
comment.count 1
iface MIXER
name 'External Amplifier'
value true
}
}
and codec specifc
Sigmatel Surround Playback Volume which change the ratio of volume of
"front" and "rear" channels
so the overall dB in the front speaker is also affected by this volume
control
control.20 {
comment.access 'read write'
comment.type INTEGER
comment.count 2
comment.range '0 - 31'
comment.dbmin -4650
comment.dbmax 0
iface MIXER
name 'Sigmatel Surround Playback Volume'
value.0 0
value.1 0
control.50 {
comment.access 'read write'
comment.type BOOLEAN
comment.count 1
iface MIXER
name 'Sigmatel 4-Speaker Stereo Playback Switch'
value false
}
control.49 {
comment.access 'read write'
comment.type BOOLEAN
comment.count 1
iface MIXER
name 'Sigmatel Output Bias Switch'
value false
}
control.51 {
comment.access 'read write'
comment.type BOOLEAN
comment.count 1
iface MIXER
name 'Sigmatel Surround Phase Inversion Playback '
value true
}
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