25 Oct
2015
25 Oct
'15
9:11 p.m.
Erik de Castro Lopo wrote:
- Is snd_pcm_set_params() supposed to work on capture handles?
Yes.
- Is my use of snd_pcm_set_params() missing something and if so what?
No. But it does not set exactly the same parameters as the manual hw_params calls.
Please check for differences with snd_pcm_hw_params_dump() (or look into /proc/asound/cardX/pcm0c/sub0/hw_params).
The program can be compiled and run in two ways:
gcc -Wall -O2 -DUSE_SET_PARAMS=1 alsa_capture.c -lasound -o alsa_capture ./alsa_capture
which fails with:
Read from audio interface failed (Input/output error)
Which driver? Any messages in the system log?
if ((err = snd_pcm_prepare (capture_handle)) < 0) {
This is done automatically by snd_pcm_hw_params().
if ((err = snd_pcm_readi (capture_handle, buffer, buffer_frames)) != buffer_frames) {
If less than the full number of frames have been read, you get a return value that is not an error code but a positive number.
Regards, Clemens