Openmoko Sound Management

Brad Midgley bmidgley at
Thu Jul 19 18:44:22 CEST 2007


>  At the moment gstreamer handles the APPLICATION-->CPU-->CODEC layers. I was
> wondering if it can be extened with control only (as there is no media
> stream) controls to cope with CODEC-->GSM CODEC-->BT interfaces as well.
> Hence having GSM call control and media player using the say system to route
> audio.

I'm not sure gstreamer is the best layer for this. Audio routing goes
beyond throwing switches in the codec. There will be cases where you'd
want to interrupt a gstreamer chain to tell it to route audio
somewhere different (like a2dp).

It seems like I saw pulseaudio running in a recent image. Pulse
already has the notion of routing audio and devices that come and go.
The wired headset appears and goes away and it might make sense to
show this as a new preferred adapter to pulse when you plug it in.

We've thought long and hard about routing audio with bluetooth. I
think pulse is the best place to handle it. It'll still be a little
tricky handling the different cases, but it looks like it will work...
eg SCO audio (selecting this route actually just throws a switch in
the dsp) and a2dp (where selecting this means sending the audio to a
different plugin that does the encode and transfer)


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