At Mon, 16 Mar 2009 15:31:58 +0100, Andreas Mohr wrote:
Hi,
On Mon, Mar 16, 2009 at 03:18:20PM +0100, Takashi Iwai wrote:
At Mon, 16 Mar 2009 14:30:01 +0100, Andreas Mohr wrote:
Hi,
On Mon, Mar 16, 2009 at 01:09:50PM +0100, Takashi Iwai wrote:
The question in the top priority is whether it's a kernel driver issue or alsa-lib converter issue. Could you check whether the sounds recorded with -Dhw (and with matching rate, format, etc) have the same noise problem at first?
OK, tried arecord -v -D hw:0 -c1 test.wav, which ended with arecord: set_params:961: Sample format non available .
arecord -v -D hw:0 -c1 -f S16_LE test.wav then ended with arecord: set_params:966: Channels count non available thus completing it into a arecord -v -D hw:0 -c2 -f S16_LE test.wav worked.
Trying this line with plughw then worked (of course, since two channels never has any problems).
Interestingly when using plughw there seems to be some LPF effect, since with hw I get lots of white noise whereas with plughw the recorded sound is dark (no higher-frequency components at all).
And audio is always being recorded properly no matter which Capture sliders position.
To state it more clearly, both hw and plughw have no issues whatsoever with -c2 -f S16_LE, any sliders position. If I then switch to plughw:0 -c2 -f U8 (IOW change to U8 format), no problems either. Trouble starts if I then change to -c1 and have both channel sliders about equal (if they're not equal then I'm getting audio returned properly).
So, the following is also problematic
% arecord -fdat -c1 -Dplughw ng.wav
while the below works?
% arecord -fdat -Dhw good.wav
Indeed, the above has problems with problematic slider positions whereas the below never has.
Err, could you be more specific about "slider positions"?
And, if it's about the alsa-lib conversion problem, we can reproduce without the hardware, e.g. via file plugin...
So, what to do?
Does the conversion by sox from good.wav to a mono-channel file work?
I assume I should be using sox good.wav -c1 good1.wav ?
If so, yes, this works, audio is there.
Just to be sure - what about below? sox good.wav -c1 good1.wav mixer 0.5,0.5
Takashi