I am trying to use the multi ALSA plugin to copy my desktop audio to the Loopback device created by snd-aloop. However, when I try to use the .asoundrc below, I get this error:
> aplay -vv test.wav
Playing WAVE 'test.wav' : Signed 32 bit Little Endian, Rate 48000 Hz, Stereo
ALSA lib pcm_params.c:2226:(snd1_pcm_hw_refine_slave) Slave PCM not usable
aplay: set_params:1314: Broken configuration for this PCM: no configurations available
.asoundrc:
pcm.both {
type multi
slaves.a.pcm "dmixer"
slaves.b.pcm "loop"
slaves.a.channels 2
slaves.b.channels 2
bindings.0 { slave a; channel 0; }
bindings.1 { slave a; channel 1; }
bindings.2 { slave b; channel 0; }
bindings.3 { slave b; channel 1; }
}
pcm.dmixer {
type dmix
ipc_key 1231
ipc_perm 0666
slave.pcm "hw:PCH,0"
slave.channels 2
slave.rate 48000
slave.format S32_LE
bindings {
0 0
1 1
}
}
pcm.loop {
type dmix
ipc_key 29637
slave {
pcm "hw:Loopback,0"
rate 48000
format S32_LE
channels 2
period_size 1024
buffer_size 9182
}
}
pcm.hubcap {
type plug
slave {
pcm "hw:Loopback,1,0"
rate 48000
format S32_LE
}
}
pcm.!default {
type asym
playback.pcm {
type plug
slave.pcm "both"
ttable [
[ 1 0 1 0 ]
[ 0 1 0 1 ]
]
}
capture.pcm "plug:dsnoop"
}
defaults.pcm.surround21.card off
defaults.pcm.surround21.device off
defaults.pcm.surround40.card off
defaults.pcm.surround40.device off
defaults.pcm.surround41.card off
defaults.pcm.surround41.device off
defaults.pcm.surround50.card off
defaults.pcm.surround50.device off
defaults.pcm.surround51.card off
defaults.pcm.surround51.device off
defaults.pcm.surround71.card off
defaults.pcm.surround71.device off
Things to note:
When I remove both dmixes, it works fine.
In the multi plugin, when I change both slaves to the same pcm, it works fine for that one pcm.
Ex.
...
type multi
slaves.a.pcm "dmixer"
slaves.b.pcm "dmixer"
...