[alsa-devel] how to convert stereo capture to mono stream (hardware incompatibility)

Clemens Ladisch clemens at ladisch.de
Thu Sep 4 12:58:16 CEST 2008

brunal wrote:
> There is an implementation of alsa in Julius, but I can't make it
> working with my USB sound card, because when alsa tries to set
> channel capture to 1, I get an error from alsa. Here is the code :
>   /* set number of channels */
>    if ((err = snd_pcm_hw_params_set_channels(handle, hwparams, 1)) < 0) {
>      jlog("Error: adin_alsa: cannot set PCM channel to %d (%s)\n", 1, snd_strerror(err));
>      return(FALSE);
>    }
> Which always return FALSE.

I'd guess this program uses a wrong device name.  Make sure that the
default device name is "default", which can automatically convert sample
formats not supported by the hardware, and not "hw".


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