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I'm running version 12.10. My PC has an built-in sound card and 3 usb sound cards of the same type. mplayer works ok for all of them using the argument -ao alsa:device=hw=2.0 for instance. vlc --aout=hw=2.0 does not work. pacmd does not list any card. Starting pulseaudio manually results in Failed to open module "alsa": file not found. hwinfo shows the built-in card only. lsusb shows the connected cards correctly and the corresponding files /sys/class/sound/pcmC?D0p/uevent look ok as well. Please advice.

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Regarding VLC, could you be a little more specific than "does not work"? – CL. Jan 13 '13 at 17:37
Sorry, '...not work' means no sound. In the meantime I removed pulseaudio. vlc now connects to alsa and sees all alsa cards available, but it ignores the command line switch 'hw=' and opens the default alsa device, which most likely is the built-in card having no speaker attached. Anyway, it looks like little progress is made, but the target is still unreached... – khan Jan 14 '13 at 21:00
Wow, a typo prevented vlc from using the wanted device: the needed option is --aout hw=2.0 (a blank between aout and hw, no =)... – khan Jan 14 '13 at 21:11

In mplayer's ao option, any : or , characters in the device name must be replaced with = or . to avoid some silly conflicts in the mplayer option parsing code. The actual device name you're using is hw:2,0.

VLC's aout option specifies the audio output module name; the device name would be specified with the alsadev option:

vlc --aout=alsa --alsadev=hw:2,0
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Thank you CL, I tried it. vlc would not accept the option alsadev. It looks like it was renamed to alsa-audio-device. Since 'aply -l' reported card 1: PCM2702 [Burr-Brown Japan PCM2702], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 – khan Jan 15 '13 at 20:26
sorry for breaking the input here – khan Jan 15 '13 at 20:27
aplay list the wanted card as #1, so I tried mplayer with this card using -ao alsa:device=hw=1.0 and it worked. Then I tried vlc using --aout=alsa --alsa-audio-device=hw:1,0 and I got several error messages: cannot open ALSA device "hw:1,0": No such file or directory and The audio device "hw:1,0" could not be used: No such file or directory. Please advice... – khan Jan 15 '13 at 20:34
This may be usefule as well: ALSA lib pcm_hw.c:1401:(_snd_pcm_hw_open) Invalid value for card – khan Jan 15 '13 at 20:42
I guess aplay -D hw:1 something.wav doesn't work either? Are the permissions on the files in /dev/snd/ correct? – CL. Jan 15 '13 at 23:47

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