[agl-discussions] 4a-softmixer initial version

[Fulup Ar Foll]

FYI,

I pushed an initial version of the proposed 4a-softmixer on 
https://github.com/iotbzh/4a-softmixer

While this is clearly a work in progress its works and support targeted 
configuration as presented during technical workshop at 
Microchip/Karlsruhe. This version propose two config sample

  - With two stereo sound cards grouped as one 4 channels board 
https://github.com/iotbzh/4a-softmixer/blob/master/conf.d/project/lua.d/softmixer-02.lua

  - With a single stereo sound card 
https://github.com/iotbzh/4a-softmixer/blob/master/conf.d/project/lua.d/softmixer-01.lua

Soft Mixer Functionalities

- Relies on Alsa snd-aloop kernel driver and expose one subdevice per 
audio-stream.

- Provide AGL application framework API to attach sound cards, create 
zone, stream, ....

- Expose Alsa control per audio-stream (mute+volume)

Work To Be Done

- Move to new controller version

- Add soft volume ramping

etc ....

Please feel free to test and provide feedback. The goal is to present an 
official candidate release for Vannes audio workshop 1st week of june.

Fulup