Re: [Alsa-user] arecord: set_params:1239: Channels count non available

[Roger <rog...@gm...>]

> On Mon, Mar 17, 2014 at 09:46:25PM +0000, James Courtier-Dutton wrote:
>On 17 March 2014 14:30, Roger <rog...@gm...> wrote:
>> I keep getting the following error whenever specifying -c 1 or --channels=1, or
>> specifying any number of channels less than two channels when using an ASUS
>> Essence STX soundcard and recording using the microphone line having a TRS
>> jack.  (Whether using the rear or front/case microphone jack.)
>>
>> $ arecord --device=hw:0,0 --format S16_LE --rate 44100 -c1 /tmp/test.wav
>>
>> arecord: set_params:1239: Channels count non available
>>
>This due to one of two reasons:
>1) The hardware cannot do it.
>2) The hardware can do it, but the device driver has not implemented
>support for it yet.

I'm guessing the later, the driver is hard coded, so people recording using the 
line-in input avoid the problem of only being able to record the left channel.  
Hard-coding for recording both channels, and then requiring users to strip or 
merge the right channel with the left channel later.

>Have you tried using plug devices or the default
>e.g
>arecord --device=plughw:0,0 --format S16_LE --rate 44100 -c1 /tmp/test.wav
>
>This will give you 1 channel, and alsa lib will do the down-mixing 2->1 for you.

Exactly one answer I was looking for.  A quick substitution via arecord to just 
record mono, whether or not using downmixing, as I was already trying within 
the dot asoundrc file.  Verified Audacity does show only one track within the 
/tmp/test.wav, and likely can now also stuff something into a dot asoundrc file 
using the above example, but will likely use a Bash alias within the .bashrc 
file.

alias arecord-mic-2s="arecord --channels=1 --device=plughw:0,0 --duration=2 
--format S16_LE --rate 48000 --vumeter=mono /tmp/test.wav && aplay 
/tmp/test.wav"


Works like a charm!  Thanks!

-- 
Roger
http://rogerx.freeshell.org/