'Twas brillig, and Wade Brown at 30/11/10 02:57 did gyre and gimble:
Pierre,
Default PulseAudio behavior is to mix in software. If you wanted to
mix in hardware, you could highjack the passthrough work I've been
doing for AC3. Essentially one device for sw mix, and a number of hw
devices
heory you'd want to group all the same-freq data together, mix it
and then pass it to the sink which would use the DSP to do the
resampling needed, which isn't really something supported right now in
the PA architecture AFAIK.
With the links you've got to most DSPs you don't actually need to
Specifically, there is a dedicated DSP on board that can resample,
multiplex and output audio. The ALSA driver actually uses this DSP,
but Pulse Audio is stuck resampling and muxing in user land before
passing data to the ALSA driver. I've been browsing around source and
documentation, and
Pierre,
Default PulseAudio behavior is to mix in software. If you wanted to
mix in hardware, you could highjack the passthrough work I've been
doing for AC3. Essentially one device for sw mix, and a number of hw
devices with no processing in PulseAudio. Still fairly hairy stuff at
this point
