Playing 2 audio files simulatanously with Alsa

dnar · 05-26-2003, 07:05 AM

I installed Alsa today, thinking Alsa allowed two concurrent audio streams to be played to a single card. This appears not so, or at least with my config.

I am running the latest freshrpm Alsa modules, my sound device is the Ensonique ES1371.

Am I mistaken, or can Alsa play two simultanous sound streams, for instance an MP3 using XMMS and desktop sounds/Gaim sound events in particular?

Cheers.

kazuni · 05-26-2003, 07:24 AM

i am not sure, but i have a SB Live! which uses the emu10k1 module - it runs simutaneous sounds no problem (i ran 2 X server sessions - one with root and one with other users and they both play mp3s using xmms at the same time with no problem)

try look at the control centre for redhat and you should be able to find settings within the sound modules

dnar · 05-26-2003, 07:26 AM

RH did not ship with Alsa, rather OSS so it has no controls for such things.

Thanks for you replay anyway... So at least with your sound card, simultaneous streams are played and mixed yes?

kazuni · 05-26-2003, 07:34 AM

yeah, that's what i was saying.. even tho that didn't do you any good -_- (i am using SuSE8.2 btw, recompiled kernel 2.4.20-4GB-athlon)

dnar · 05-26-2003, 07:42 AM

Ok, I suspect my card does not support hardware mixing. I'll do a little more digging through mailing lists etc, I may have to upgrade to a nicer card

dnar · 05-26-2003, 08:00 AM

Ok, I got it to work.

The SoundBlaster PCI 128 (Ens1371) does support 2 streams, via 2 x DAC's.

I found that I could initiate 2 concurrent streams like so:-

Code:

aplay -D hw:0,0 test1.wav &
aplay -D hw:0,1 test2.wav

That is the 1st stream to DAC 1 (hw:0,0) and the 2nd to DAC 2 (hw:0,1). I then found that the Alsa plugin for XMMS allows configuration for either DAC. I set XMMS to use DAC 1 (it used DAC 2 by default). Now I have conccurrent sounds from XMMS and my desktop/applications! w00t!

Thanks for your help.