On May 07 12:21:30, Alexandre Ratchov wrote:
> On Sat, May 07, 2011 at 10:52:09AM +0200, Jan Stary wrote:
> >
> > I just bought me the "new" M-Audio USB MobilePre (MK-II):
> >
> > uaudio0 at uhub2 port 2 configuration 1 interface 0 "M-Audio MobilePre" rev
> > 1.10/10.00 addr 2
> > uaudio0: audio rev 1.00, 0 mixer controls
> > audio0 at uaudio0
> >
> > Indeed, 'mixerctl -a' shows nothing; but
> > aucat -u -C 0:1 -e s24le -r 48000 -o in.wav
> > seems to be recording anyway (and the sound
> > is very good).
>
> Cool.
Is it OK for an uaudio(4) device to have 0 mixer controls?
I can control the respective inputs/outputs with the device's (hardware)
knobs, but having 0 (software) mixerctl variables still seems a bit strange.
Is it possible that the device really has 0 controls to expose via USB
audio (and uaudio just correctly reports that), or is this a sign that
the dovice is not fully supported (or possibly not class-compliant)?
> FWIW, above command will convert everything to 16-bit, and then
> back to 24-bit, truncating lower 8 bits. To record 24-bit with no
> precision loss, you have to recompile aucat in 24-bit mode.
>
> make COPTS=-DADATA_BITS=24
Thank you. Is this documented somewhere?
Is the 24bit functionality still considered experimental?
I was trying to somehow 'test' that the device really can record 24bit
samples as advertised (that's why I bought it). Running
aucat -u -C 0:1 -e s24le -r 48000 -o in.wav
records a 24bit file all right; anyway, the running aucat server
(aucat -l) would resample/reformat for me even if the device could
not do 24b/48kHz, right? So I killed the aucat server and run the
above command again, resulting in a 24bit file again. Would the
aucat command (without aucat -l running) also resample/reformat
into the desired format even of the device cannot do it?
I very much doubt that this is the correct way to find out of course.
What would be the correct way to find out what the device can physically do?
All I know about is .../cap.c somewhere in the audio source tree. Is there
a 'real' tool, exposed and documented?
Thank you for your time
Jan
