[LAU] Alsa-to-Jack bridge using snd-aloop documentation

[Robin Gareus]

On 04/03/2012 07:57 AM, michael noble wrote:
> Since the unofficial wiki seems to have disappeared, the documentation
> of the "Jack and Loopback device as Alsa-to-Jack bridge" has gone with
> it. Neither google cache nor the wayback machine fare able to serve a
> copy of the page. There are plenty of references to the wiki page on
> the web, but no-one seems to have mirrored the page. Does anyone
> happen to have a copy of the documentation lying around?
> 
> Michael

Not a copy of the whole article, but the essentials - here using zita-aj
instead of for alsa_in/out

-------------------~/.asoundrc----------------------
# playback PCM device: using loopback subdevice 0,0
pcm.amix {
  type dmix
  ipc_key 219345
  slave.pcm "hw:Loopback,0,0"
}

# capture PCM device: using loopback subdevice 0,1
pcm.asnoop {
  type dsnoop
  ipc_key 219346
  slave.pcm "hw:Loopback,0,1"
}

# duplex device combining above  PCM devices
pcm.aduplex {
  type asym
  playback.pcm "amix"
  capture.pcm "asnoop"
}

# ------------------------------------------------------
# default device

pcm.!default {
  type plug
  slave.pcm "aduplex"
}

## use with
## modprobe snd-aloop pcm_substreams=2
## jackd ...
#
# zita-a2j -L -d hw:Loopback,1,0 -j cloop -n 3 -p 256 &>/dev/null &
# zita-j2a -L -d hw:Loopback,1,1 -j ploop -n 3 -p 256 &>/dev/null &
# sleep .5
## cloop -> jack output ports
# jack_connect cloop:capture_1 system:playback_1 &>/dev/null
# jack_connect cloop:capture_2 system:playback_2 &>/dev/null
#
## jack input ports -> ploop
# jack_connect system:capture_1 ploop:playback_1 &>/dev/null
# jack_connect system:capture_2 ploop:playback_2 &>/dev/null