[LAU] Streaming setup with OBS and JACK

Len Ovens len at ovenwerks.net
Wed Jul 25 17:58:50 CEST 2018

On Wed, 25 Jul 2018, David Kastrup wrote:

> Paul Davis <paul at linuxaudiosystems.com> writes:
>> On Wed, Jul 25, 2018 at 2:56 AM, <hollundertee at gmx.net> wrote:
>>> 2) Is there a reliable and if possible hassle free way to get ALSA and
>>> PA into JACK? ALSA loopback would probably not work for programs using
>>> PA directly.
>> ​it works just fine. I use it with Skype with no issues.​
> For pulseaudio/jack, I use the following "pulsejack" script.  Without
> arguments, it tries connecting a running jackd with a running pulseaudio
> system.  With arguments, it kills any existing jackd, then starts a new
> one with the given arguments and connects it with a running pulseaudio
> system.  I'd like it to use things like jack_wait and similar in order
> to avoid the clumsy manual job management but haven't been able to make
> this robust enough (namely without having it lock up or not work in some
> situations).

I have been using PA and Jack bridged for about 4 years now. My script has 
changed during that time, not for problems but to make it more generic. I 
use jackd as the audio device for pulse. That is I remove the alsa and 
udev modules from pulse (after starting). This ensures that jack is always 
the default i/o and as a side benefit allows jack to freewheel with no 
problems and gives better xrun immunity. I do not use the jackdbus-detect 
module, but rather use jacksink or jacksource modules as needed to ensure 
separate stereo pairs rather 4 channels being used as suround... I always 
set the pulse modules _not_ to auto connect, prefering to have 
jack_connect, jack_disconnect or jack-plumbing do that job to the port I 
want connected (system_1/2 are not always right).

I use this for all desktop audio, all the time and have found this to be a 
robust solution. I have also set up a systray button that drops the 
PA-jack bridge for times I wish to use a lower latency than pa does well 
(or some of the pa clients like skype that don't handle low latency at 

There is very little manual anything after configuration. Both jack and 
pulse are started automatically at session start and run till session end. 
The point of jack in the first place is to allow routing changes on the 
fly in a manual way, auto connect just gets in the way of that except for 
reconnecting things when restarting a jack client to where they were 
before it stopped.

I use zita-ajbridge if I must have more than one audio device. The truth 
about this is that I use more than one audio device just to make sure that 
it works and so that I can help other people get their USB mic working. I 
have only one audio interface worth using for anything where quality 
matters: my delta 66 a semi-pro audio interface that is long obsolete. I 
have also found that I don't use more than 2 channels at a time anyway so 
even 6 i/o has been overkill for me.

Len Ovens

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