[alsa-devel] --separate-channels issues

[hong zhang]

Takashi,

If use hw:0,1, no "-c 4" is allowed. That is why I use plughw see following:
 
arecord -f S16_LE -r 48000 -c 4 -D hw:0,1 --separate-channels c1.wav c2.wav c3.wav c4.wav

Recording raw data 'c1.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
arecord: set_params:1048: Access type not available

hw:0,1 works with no "-c" option only. I even try it on my laptop.

---henry

--- On Tue, 5/10/11, Takashi Iwai <tiwai at suse.de> wrote:

> From: Takashi Iwai <tiwai at suse.de>
> Subject: Re: [alsa-devel] --separate-channels issues
> To: "hong zhang" <henryzhang62 at yahoo.com>
> Cc: alsa-devel at alsa-project.org
> Date: Tuesday, May 10, 2011, 11:40 AM
> At Tue, 10 May 2011 09:34:40 -0700
> (PDT),
> hong zhang wrote:
> > 
> > Takashi,
> > 
> > When I run following commands with 2 pins inputs.
> > 
> > $ arecord -f S16_LE -r 48000 -c 4 -D plughw:0,1
> --separate-channels c1.wav c2.wav c3.wav c4.wav
> > 
> > hd c3.wav and c4.wav returns 0 but c1.wav and c2.wav
> got right data.
> > Such as 
> > $ hd c3.wav 
> > 00000000  00 00 00 00 00 00 00 00  00 00 00
> 00 00 00 00 00  |................|
> > *
> > 005ad000
> 
> Use hw:0,1 instead of plughw:0,1.  If the hardware
> really supports the
> multi-channels, it should work in that way.  I guess
> you didn't notice
> that the input is 2 channels because plughw covers it.
> 
> > Also, I see trigger Rx start command and then stop
> command immediately.
> 
> This sounds like a driver issue.
> 
> 
> Takashi
>