'Twas brillig, and Stefan Schoenleitner at 13/04/10 16:23 did gyre and gimble:
Hi,
I finally managed to write an ALSA I/O plugin that does what I want. The plugin supports both playback and capture.
Now I would like to write a simple audio application that takes audio samples
- from the microphone and plays it back on my plugin
and
- from the plugin (capture) and plays it back on the speakers
This sounds like something that would be more appropriate for jack http://jackaudio.org/
Hence as long as the application is running, it should do the above.
Is there a special ALSA way to route audio from one PCM to another ?
If not, I suppose it would just work if I open the plugin PCM and the
hw PCM at the same time and copy audio frames between them ?
Dealing with this can be quite complex, especially if the pcms are clocked of different sources, you have to deal with a degree of resampling to ensure that clock skew doesn't get out of control.
The module-loopback plugin in PulseAudio does a similar thing (routes audio from a source to a sink) and as such has to deal with these clock skew problems.
Col