Pulse Audio and Jack in Maverick

[Marc R.J. Brevoort]

On Fri, 3 Sep 2010, ttoine at ttoine.net wrote:

> I just saw in the Maverick beta wiki pages that in Ubuntu Studio
> Maverick, some work has been done for better integration between
> PulseAudio and Jackd. Is it available for vanilla Ubuntu too ?
> If not, does this need to install a specific package, or is there a
> tweak we can document for non "Studio" users? I ask that because I am
> downloading Maverick beta at the moment, but not the Studio, the
> standard one, with the aim to test and document that important point!

I've just set up a system that plays back pulseaudio over jack over
ALSA on Lucid.
The following are not step-by-step instructions but may help you
get started.

You'll need pulseaudio-module-jack, the regular set of
jack util packages;

~/.asoundrc containing this:
pcm.pulse {
     type pulse
}
ctl.pulse {
     type pulse
}
pcm.!default {
     type pulse
}
ctl.!default {
     type pulse
}

follow the recommendations that qjackctl gives you when trying to start 
it and failing;

create two files,

1. ~/bin/jack.pa containing the following:

#!/bin/bash
# (two following lines matter most)
pactl load-module module-jack-sink
pactl load-module module-jack-source

pactl load-module module-native-protocol-unix
pactl load-module module-volume-restore
pactl load-module module-default-device-restore
pactl load-module module-rescue-streams
pactl load-module module-suspend-on-idle

2. a file ~/bin/startjack containing this:
#!/bin/bash
/usr/bin/jackd -dalsa -dhw:0 -r44100 -p1024 -n2

(which is the line shown by qjackctl after successful startup)

give both file execute permissions;

chmod +x ~/bin/*

and add them as startup programs.

re-login, in sound preferences set "Jack sink" as
default audio device.

Thus you'll have a system that (in theory) directs all its audio
through JACK.

One minor thing is that when starting qjackctl, pulseaudio is
suspended, which is not ideal. As you're running the jack
daemon as startup program, You'll also want to tell qjackctl
not to terminate jack on exiting.

I hope this is of some use to you even though terribly
incomplete and written up from memory too so probably full
of errors.

Best,
Marc