Re: 24 bit usb sound on lenny
On Sat, Feb 07, 2009 at 03:54:41PM +0100, Johannes Wiedersich wrote:
> Hallo all!
>
> On switching my usb sound card to 24bit audio, all applications using
> the card will crash/segfault:
>
> $ aplay led_zeppelin-houses_of_the_holy-a.wav
> Playing WAVE 'led_zeppelin-houses_of_the_holy-a.wav' : Signed 16 bit
> Little Endian, Rate 44100 Hz, Stereo
> Segmentation fault
There are many wrinkles and ways of solving problems
with Linux audio.
At the ALSA level, the 'default' pcm device as provided by modern
kernels automatically performs format conversion. Maybe some
of the others, too.
$ aplay -L
provides a list of your system's ALSA pcm sound devices.
okay, here's a test with a 24-bit mono file outputing to
my 16-bit soundcard.
aplay organ_6.wav -D default (plays normally)
Now for your system, you should reboot or unplug and replug
your USB sound device after changing to 24-bit to ensure the
ALSA driver reads the 24-bit configuration.
You can also choose to specify in your $HOME/.asoundrc file what the
output format to the soundcard should be for a particular
device.
I find the Ecasound provides an easy way to handle
format conversions.
$ ecasound -i cd-stereo.wav -f:s24_le,2,44100 -o alsa,hw:0
Ecasound is a swiss-army knife of audio processing,
can do many common audio processing tasks.
> kaffeine, amarok, xine etc. all just crash.
It sounds like a configuration problem, maybe ALSA
needs to be told that your USB soundcard is set to 24 bits.
>
> Trying to record some anaolg input with 24bit also fails:
>
>
> $ arecord -f S24_LE -c 2 -r48000 24-48k-testa.wav
> Recording WAVE '24-48k-testa.wav' : Signed 24 bit Little Endian, Rate
> 48000 Hz, Stereo
> ^CAborted by signal Interrupt...
>
> appears to behave as expected, but the generated file is finishes at 44
> bit.
>
> Everything works nice on 16 bit/48 kHz:
>
> 14:30:43-johannes@e13-v21:/home/audio/wav$ aplay
> led_zeppelin-houses_of_the_holy-a.wav
> Playing WAVE 'led_zeppelin-houses_of_the_holy-a.wav' : Signed 16 bit
> Little Endian, Rate 44100 Hz, Stereo
This suggests that you are 99% there, since your ALSA driver is
already taking care of converting the signal from 44100 to
48000 Hz.
Good luck with that last 1%. 24 bits will help if you
are doing multitrack stuff. In which case you might
consider Audacity (friendly GUI), Ardour (total pro)
or even Nama (http://ecmd.infogami.com) which I have
developed using Ecasound for audio processing.
HTH
> *Does anyone have 24 bit sound working with debian lenny?*
>
> FWIW, I have a Terratec phase 26 usb sound card. It features a switch to
> change it's audio quality settings for 16 bit/48 kHz, 24/48, 24/96.
>
> My modprobe settings to load it as card 0:
>
> $ more /etc/modprobe.d/sound
> alias snd-card-0 snd-usb-audio
> options snd-usb-audio index=0
>
> Any help and pointers to improve my sound experience are well appreciated!
>
> Thanks,
>
> Johannes
>
--
Joel Roth
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