[LAU] pulseaudio with jack

Hi, A few people have been discussing the status of jack support with pulseaudio at pulseaudio-discuss. I thought that it would be useful to post the main details for people here and also to have a more complete overview in the search engines, I am following up on the dbus situation in regards to legacy jack. However the scripts below should be useful for people who use non dbus jack and still want to run pulseaudio at the same time. They can be called from qjackctl for convenience. ++++++++ Recent PA versions do just that. If you have a recent dbus'ified version of JACK and PA 0.9.15 then PA will give up access to the device when JACK asks for it and take it back afterwards. JACK is king and PA obeys. ++++++++++ As mentioned we have two modules to connect PA to JACK. Called module-jack-sink and module-jack-source. Presumably those are the modules included in that package. pulseaudio from Newer PA and JACK versions cooperate in this way automatically. If you fire up JACK PA will go out of the way for that device. And after JACK is done PA takes the device back. JACK is king and PA will comply. In older versions you can use a tool like "pasuspender". It will suspend PA's access to the audio devices temporarily as long as child process is running. If you make that child process JACK you have a neat way to make JACK and PA not fight for device access. A more brutal way is to stop PA with "pulseaudio -k" before you run JACK and then start PA with "pulseaudio -D" afterwards. But that probably won't work that nicely since PA is configured to autospawn in most cases these days -- which you can disable however by editing /etc/pulse/client.conf +++++++++++ jackdbus to work legacy I don't use Jack myself (anymore), but from what I understand, this feature is tied to jackdbus, because D-Bus is the protocol Jack and PA use to communicate with each other. When PA is running and Jack is started, Jack can't force PA to release the device, if PA doesn't want to cooperate (well, it could use the "kill" command or something...). PA cooperates by listening for device release requests using D-Bus, so Jack has to use D-Bus too. And apparently jackdbus is the only implementation that does that. ++++++++++++ Currently what I'm doing, which is just a bit hackish, is to use pactl list to get the IDs of the alsa sink/source, unloading them via pactl unload-module, then starting JACK and loading the appropriate module-jack-sink/source. In the reverse, again pactl list to get the relevant IDs, unload via pactl unload-module, then loading the ALSA modules. This actually works most of the time, but there's a segmentation fault that I've encountered recently when unloading the jack modules while sound is playing. The bug report with traces has been submitted at http://www.pulseaudio.org/ticket/560 and Lennart will be getting round to it. Okay. As I warned, it IS rather hackish. There's two scripts, the first one I name pulse-nojack, the second I name pulse-withjack. Sequence of events is as follows:- 1. Start pulseaudio (I comment out every HAL/alsa-related line in /etc/pulse/*.pa, so pulse just starts with a null sink if it hasn't yet). Using the --start means if pulse is already started nothing will be done (use current server). 2. Check for modules needing to be unloaded. Just pactl with some greps and sed, then pactl unload-module. 3. Check for jackd (this may need to be changed once jack2 comes out, I've been monitoring the jackdbus conversations and things are in real flux there), kill/start if needed. 4. Load the modules which need loading. Please note there's probably some wrapping problems with this code. Please check it out, should not be hard to figure out what to do. FIRST SCRIPT: PULSE-NOJACK---------------------------------------------- #!/bin/bash # ORIGINAL SCRIPT FROM: #http://ubuntuforums.org/showthread.php?t=904379&highlight=bash+ping # edited by edmondt in: http://ubuntuforums.org/showthread.php?t=939183 # edited by ngoonee, Feb 2009 # Start pulseaudio if it hasn't already been started pulseaudio --start # Name the module to be unloaded. MODULE="alsa" # The line used to startup JACK. JACKSTART="/usr/bin/jackd -R -dalsa -r44100 -p64 -n3 -D -Chw:0 -Phw:0" SINKID=$(pactl list | grep -B 1 "Name: module-$MODULE-sink" | grep Module | sed 's/[^0-9]//g') SOURCEID=$(pactl list | grep -B 1 "Name: module-$MODULE-source" | grep Module | sed 's/[^0-9]//g') if [ -e $SINKID ]; then echo $MODULE sinks/sources not loaded, proceeding.... else echo $MODULE sinks/sources are loaded, ID of $MODULE sink is $SINKID ID of $MODULE source is $SOURCEID... echo Unloading module $SINKID and $SOURCID pactl unload-module $SINKID pactl unload-module $SOURCEID fi if [ $( pidof jackd ) ]; then echo JACK is running, nothing to be done. else echo JACK is not running, starting JACK... $JACKSTART & sleep 3 fi JACKSINKID=$(pactl list | grep -B 1 "Name: module-jack-sink" | grep Module | sed 's/[^0-9]//g') JACKSOURCEID=$(pactl list | grep -B 1 "Name: module-jack-source" | grep Module | sed 's/[^0-9]//g') if [ -e $JACKSINKID ]; then echo JACK sinks/sources not loaded, loading now... pactl load-module module-jack-sink pactl load-module module-jack-source else echo JACK sinks/sources are loaded, ID of JACK sink is $JACKSINKID ID of JACK source is $JACKSOURCEID... fi exit 0 ------------------------------------------------------------------------ SECOND SCRIPT: PULSE-WITHJACK------------------------------------------- #!/bin/bash # ORIGINAL SCRIPT FROM: # http://ubuntuforums.org/showthread.php?t=904379&highlight=bash+ping # edited by edmondt in: http://ubuntuforums.org/showthread.php?t=939183 # edited by ngoonee, Feb 2009 # Start pulseaudio if it hasn't already been started pulseaudio --start # Name the module to be unloaded. MODULE="alsa" # The line used to startup JACK. JACKSTART="/usr/bin/jackd -R -dalsa -r44100 -p64 -n3 -D -Chw:0 -Phw:0" SINKID=$(pactl list | grep -B 1 "Name: module-$MODULE-sink" | grep Module | sed 's/[^0-9]//g') SOURCEID=$(pactl list | grep -B 1 "Name: module-$MODULE-source" | grep Module | sed 's/[^0-9]//g') if [ -e $SINKID ]; then echo $MODULE sinks/sources not loaded, proceeding.... else echo $MODULE sinks/sources are loaded, ID of $MODULE sink is $SINKID ID of $MODULE source is $SOURCEID... echo Unloading module $SINKID and $SOURCID pactl unload-module $SINKID pactl unload-module $SOURCEID fi if [ $( pidof jackd ) ]; then echo JACK is running, nothing to be done. else echo JACK is not running, starting JACK... $JACKSTART & sleep 3 fi JACKSINKID=$(pactl list | grep -B 1 "Name: module-jack-sink" | grep Module | sed 's/[^0-9]//g') JACKSOURCEID=$(pactl list | grep -B 1 "Name: module-jack-source" | grep Module | sed 's/[^0-9]//g') if [ -e $JACKSINKID ]; then echo JACK sinks/sources not loaded, loading now... pactl load-module module-jack-sink pactl load-module module-jack-source else echo JACK sinks/sources are loaded, ID of JACK sink is $JACKSINKID ID of JACK source is $JACKSOURCEID... fi exit 0 ------------------------------------------------------------------------ -- Patrick Shirkey Boost Hardware Ltd