[linux-audio-user] volume plugin

[Clemens Ladisch]

olig9 at 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