I am currently working on a shared library to control master volume/balance/mute/etc ... under linux.
I am trying to use the alsa library to this purpose (http://www.alsa-project.org/alsa-doc/alsa-lib/index.html).
I figured how to modify the master volume, but i am unable to find anything else.
At this point I'm starting to wonder if it's even possible with the alsa lib.
Does any one have ever done something similar and could possibly show me the way?
Totally forgot to bring back the solution here
So, for the balance, you will have to use the function :
int snd_mixer_selem_set_playback_volume
http://www.alsa-project.org/alsa-doc/alsa-lib/group___simple_mixer.html#ga1e4556740beefc8bed40677a316e60ac
with the enum that you can find here : http://www.alsa-project.org/alsa-doc/alsa-lib/group___simple_mixer.html#gaf01a92f33cc46d0b3878d65afcc41b97 as the second parameter
and, to mute it is the function : int snd_mixer_selem_set_playback_switch
Hope this will help someone... one day ...