Hi all,

I am developping an open-source C++ softphone based on Alsa. We used to use Portaudio but we recently decided to switch to Alsa. I am quite unexperimented in Alsa dev and I got some difficulties to make it work fine.

My capture and playback devices are plughw:0,0. I am using read/write transfers. When I disable the capture, playback works fine; when I disable the playback, capture works fine. The problems occurs when I used them together. If I set hardware parameters for both, the playback sound is awful and there is no capture, and finally core dumped. If I set hardware parameters for the playback stream only, the playback works fine, but no capture, I just get an echo with an input/ouput error.

Where do you think the problem comes from? Isn't it possible to set hardware configuration for playback and capture? Is there a hardware ring buffer for each stream ?

Thanks for your help

Manu