ALSA: Relation between period size of speaker and mic

Question

I have audio conferencing device which has a mic and speaker. Both mic and speaker having same sampling rate set by snd_pcm_hw_params_set_rate_near() say 8000 H

Answer 1

What period sized and buffer sizes are supported depends on the driver, but if it's the same device, it's likely that the playback and capture devices support the same parameters.

Whether the parameters need to be the same depends on how your application accesses these devices. As far as the driver is concerned, these devices work independently.

What buffer/period sizes to use depends on how you want to balance latency, power usage, and over/underrun safety. Latency is directly proportional with the buffer size on playback devices or the period siz on capture devices. Power usage is increased slightly by shorter periods. Xrun safety is increased by larger buffers, and a little by shorter periods.