Re: Multiple Sound Streams out of a single card

[AthlonRob <athlonrob@data.4t3.com>]

On Sat, 2003-09-13 at 23:06, Paul Davis wrote:
> ALSA now offers the "dmix" plugin layer that allows multiple
> applications to write to a PCM device without locks. just tell an ALSA
> aware app to use "dmix:0" and both it and many other apps will all be
> able to share the device.

Wow, it's good to see something like that.  :-)

I just tried it, though, and it didn't seem to want to work for me...

With my .asoundrc looking like this:

pcm.main {
        type dmix
        slave {
                pcm default
        }
}

I got this, running alsaplayer -d main /path/to/wav/file :

ALSA lib pcm_dmix.c:1184:(_snd_pcm_dmix_open) Unique IPC key is not defined
snd_pcm_open: Invalid argument (main)
Failed to initialize plugin!
Failed to register plugin: /usr/lib/alsaplayer/output/libalsa_out.so
Failed to load output plugin "alsa". Trying defaults.
ALSA lib pcm_dmix.c:1184:(_snd_pcm_dmix_open) Unique IPC key is not defined
snd_pcm_open: Invalid argument (main)
Failed to initialize plugin!
/usr/lib/alsaplayer/output/libalsa_out.so failed to load

If I run alsaplayer -d dmix:0 /path/to/wav/file, I get this:

ALSA lib pcm.c:1908:(snd_pcm_open_noupdate) Unknown PCM 0
ALSA lib pcm_dmix.c:954:(snd_pcm_dmix_open) unable to open slave
snd_pcm_open: No such file or directory (dmix:0)
Failed to initialize plugin!
Failed to register plugin: /usr/lib/alsaplayer/output/libalsa_out.so
Failed to load output plugin "alsa". Trying defaults.
ALSA lib pcm.c:1908:(snd_pcm_open_noupdate) Unknown PCM 0
ALSA lib pcm_dmix.c:954:(snd_pcm_dmix_open) unable to open slave
snd_pcm_open: No such file or directory (dmix:0)
Failed to initialize plugin!
/usr/lib/alsaplayer/output/libalsa_out.so failed to load

So I see it really isn't working for me.

> and remember that Linux (and Mac OS X) also have JACK, which offers a
> service that isn't exactly matched on Windows, though rewire comes
> close, sort of.

I see how the various Linux audio offerings may be superior to what you
can do with Windows, in a real professional setup... but for being able
to play multiple things at once, unless DMIX pans out, Windows may have
us beaten.  :-\

Is there a way to force OSS emulation to use the dmix plugin?

:::off to grep the great WWW for dmix info:::

Rob



-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf