[LAU] Ubuntustudio 12.04 audio?

Len Ovens len at ovenwerks.net
Mon Aug 20 14:33:55 UTC 2012

On Mon, August 20, 2012 3:45 am, Mac wrote:

> So far my poking around on the net indicates that dbus service between
> pulse and jack are involved. (if you uncheck the start dbus in
> qjackctrl only the firewire source/sinks show up).
> The pulse source/sinks are provided by pulseaudio-module-jack.
> What control over how things are named or created is still
> unknown...to me at least.

Ok I have looked at what I can find of on the pulse-jack bridge. At the
least it should be possible to turn the auto connect feature off. In the
change the line:
load-module module-jackdbus-detect
load-module module-jackdbus-detect connect=no

This file will need to be edited sudo BTW...
then do the command pulseaudio --kill so pulse respawns and picks up the
new config. Now when starting jack pulse and system will show up but with
no connections. manually connect system/capture to PulseAudio Jack
Source/front-left and capture_1 to front-right and use qjackctl's patchbay
to save this configuration so you can reconnect this way easily. (even
automatically at jackstart from qjackctl). Unfortunately, using the save
current setup option in patchbay does not work. It seems the patch bay
only saves whole device connects. So you have to create four new dummy
devices in the patch bay (two on either side with add. That have only
ports each. The order of ports in these defines is how they will connect.
Or just leave it unconnected and connect manually as needed.

I haven't played with this much... just enough to confirm I could get
stereo connects and that I could switch left and right.

The pulse source and sink modules have command-line options to set them to
only 2 outputs (I wish that was the default) but because they are started
by module-jackdbus-detect, there seems to be no where to put these
options. However, if you normally only have FW as your only output and so
have Jack always running it may be possible to hard start the source and
sink instead of the detect module. Then the options could be set. Still no
connect as it would still choose 1 and 2 instead of 0 and 1.

I am hearing that the FW stack is being moved to ALSA (or added?) but I
don't know how far that is away from actually happening.

Len Ovens

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