3 Apr
2004
3 Apr
'04
12:45 p.m.
Hello,
my onboard sound chip (CMedia 9739, on Epox 8RDA3+, with nforce2
chipset) doesn't support volume changing in hardware (CMedia's cmaudio
driver for OSS does all the volume calculation in software). That means
that I'm unable to change the volume with alsamixer or similar programs.
Now my question: is it possible to tell Alsa to change the volume in
software? Is there a plugin that does this? I've already tried the
"Route & Volume" plugin, but it doesn't do anything. XMMS plays sound
still at full volume, and mplayer says "alsa-control: error setting left
channel, Invalid argument" when changing volume.
My asound.conf entry for it looks like this:
pcm.nforcevol {
type route
slave {
pcm "hw:0,0"
channels 2
}
ttable.0.0 1;
ttable.1.1 1;
}
Does anyone has an idea how to get volume control? Btw. I'm using the
snd-intel8x0 driver for this chip.
Thanks in advance,
Oliver Gerlich
5 Apr
5 Apr
5:39 a.m.
Oliver Gerlich wrote:
my onboard sound chip (CMedia 9739, on Epox 8RDA3+,
with nforce2
chipset) doesn't support volume changing in hardware (CMedia's cmaudio
driver for OSS does all the volume calculation in software). That means
that I'm unable to change the volume with alsamixer or similar programs.
Now my question: is it possible to tell Alsa to change the volume in
software? Is there a plugin that does this?
It would be possible to write such a plugin, but this hasn't been
done.
I've already tried the "Route &
Volume" plugin, but it doesn't do
anything.
This plugin applies a static volume setting, you won't get a mixer
control.
Regards,
Clemens
6:57 a.m.
Clemens Ladisch wrote:
Oliver Gerlich wrote:
Then here are my next questions :)
1.) Is it really possible to get inside a plugin the PCM & Master volume
settings that are set eg. with alsamixer?
2.) Would it be better to do all this in a new plugin, or better inside
the existing intel8x0 driver, or inside a new (yet to be written :)
snd-cmaudio driver, or in another completely different way? I'd be
willing to spend some time in getting my soundchip to work, but then I
want to do it right.
Oliver
my onboard sound chip (CMedia 9739, on Epox
8RDA3+, with nforce2
chipset) doesn't support volume changing in hardware (CMedia's cmaudio
driver for OSS does all the volume calculation in software). That means
that I'm unable to change the volume with alsamixer or similar programs.
Now my question: is it possible to tell Alsa to change the volume in
software? Is there a plugin that does this?
It would be possible to write such a plugin, but this hasn't been
done.
11:59 a.m.
olig9(a)gmx.de wrote:
1.) Is it really possible to get inside a plugin the
PCM & Master volume
settings that are set eg. with alsamixer?
2.) Would it be better to do all this in a new plugin,
Yes. Yes.
In ALSA, everything is a plugin. This is obvious with pcm plugins
like dmix, but "hw" is a plugin, too (that just happens to access the
hardware driver).
For mixer controls and related stuff, there are ctl plugins. The only
one so far is the "hw" plugin, which provides access to those controls
implemented by the hardware driver.
A volume scaling plugin would consist of a pcm plugin that would scale
its input data before handing it off to a slave plugin, and of a
related ctl plugin that would provide a virtual volume control and
hand off requests for all other controls to a slave plugin.
Regards,
Clemens
7:15 p.m.
Clemens Ladisch schrieb:
olig9(a)gmx.de wrote:
Thanks for your help so far. I wonder that nobody has written such a
plugin yet...
Anyway, do you know if there's some documentation about writing an ALSA
plugin (apart from the existing sources)? Or is there a "simple plugin"
which just passes data along without changing anything (maybe
pcm_plugin.c is something like that)? That would be a good base for this.
Oh, and are there examples for the ctl plugins?
Oliver
1.) Is it really possible to get inside a plugin
the PCM & Master volume
settings that are set eg. with alsamixer?
2.) Would it be better to do all this in a new plugin,
Yes. Yes.
In ALSA, everything is a plugin. This is obvious with pcm plugins
like dmix, but "hw" is a plugin, too (that just happens to access the
hardware driver).
For mixer controls and related stuff, there are ctl plugins. The only
one so far is the "hw" plugin, which provides access to those controls
implemented by the hardware driver.
A volume scaling plugin would consist of a pcm plugin that would scale
its input data before handing it off to a slave plugin, and of a
related ctl plugin that would provide a virtual volume control and
hand off requests for all other controls to a slave plugin.
Regards,
Clemens
7567
days inactive
7569
days old
linux-audio-user@lists.linuxaudio.org
4 comments
3 participants
participants (3)
-
Clemens Ladisch -
olig9＠gmx.de -
Oliver Gerlich