On Fri, Aug 31, 2012 at 8:39 AM, Alexandre <alexduthil@gmail.com> wrote:

Hi

Kinda new to linux audio and still a bit new to dev generally and I'm trying to understand the basis of linux audio.

By that, I mean the ALSA API :
I would like to use the PCM interface and the mixer interface to mix 2 sounds

the mixer interface does not do that. its an API to control the hardware mixer (if any) present in the audio interface hardware. a lot of current audio interface hardware is incapable of mixing sound from multiple sources, so this is generally done in software.