[alsa-devel] [alsa-lib, dmix] Support for S24_3BE

Vincent Vinel v.vinel at gmail.com
Sat Dec 22 01:43:13 CET 2012


The bugtracker seems to be down, so I'm posting here instead.

I was trying to use software mixing with my Native Instruments USB
soundcard (snd-usb-caiaq), but all attemps to use the dmix pcm ended
up with the rather unhelpful error :
ALSA lib pcm_dmix.c:1311:(_snd_pcm_dmix_open) Unsupported format
When using the hw pcm, however, aplay was kind enough to display the
list of available formats, which in my case was limited to S24_3BE.
A quick check confirmed that dmix doesn't support that format, which
happens to be the only format available for NI USB soundcards (as
defined in snd-usb-caiaq).

Is it worth writing a patch for 24bit big-endian support in dmix ?
External soundcards like these ones are usually used for realtime
effects processing and low-latency audio, things for which dmix
proably isn't suited anyway.

Vincent Vinel

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