Re: [Alsa-user] playing / recording mono on a stereo-only hardware

[Giuliano P. <po...@sh...>]

On Mon, 25 Jan 2010 10:34:41 +0100 (CET)
Guennadi Liakhovetski <g.l...@gm...> wrote:

> On Mon, 25 Jan 2010, Clemens Ladisch wrote:
> 
> > Guennadi Liakhovetski wrote:
> > > Is there a way to tell alsa-lib to duplicate the mono-channel during
> > > playback and to mix recorded channels, if mono recording is requested?
> > 
> > Yes, with the "plug" plugin.  It should be used automatically by the
> > "default" and "plughw" devices.
> 
> Do I need any asoundrc for this or should this also happen without one? 
> This "plug" plugin is built into the libasound? I was advised to use 
> config like
> 
> pcm.!default {
>         type plug
>         slave {
>                 pcm "hw:0,0"
>                 channels 2
>         }
>         route_policy duplicate
> }
> 
> but, unfortunately, it didn't help.

Try something simpler:

arecord -v -Dplughw:0 -c1 -r44100 -fS16_LE out.wav

It prints the given parameters and, if the format is not supported by the
card, it also prints the choosen settings. In that case audio data is
transparently converted to the format you requested.
You shouldn't have to specify plughw: because it's the default.


-- 
Giuliano.