Re: [Jack-Devel] Jack Audio Question

On Thu, 21 May 2015, Adrian Knoth wrote:

> On 05/20/15 11:49, Miguel Martin wrote:
> 
> > Hi there,
> > 
> > I'm asking about your API jack audio. I'm not sure if you are the lead
> > developers or not, but you're the only emails I could find that
> > contributed to this project. I just want to ask: is it possible to
> > control application level volume in OS X and Linux? If so, can you give
> > me any resources or point me in the right direction?
> 
> You are looking for jack-devel@. CCed now.
> 
> And the answer is no, JACK does not control application level volume, it
> just forwards and merges audio streams.

> If you want volume control, use a mixer (maybe one of not too many
> jack-based mixers), so you can adjust each jack client's volume in one
> place.

My audio interface has no hardware mixer, so I asked for such a feature.
I'd appreciate a "master volume" in jackd, but no developer wants jackd
to deal with that.

I found a solution that works for me:

- I start a mixer, e.g. jack_mixer
- I start jack.plumbing with a ruleset that disconnects my jack clients
  (even ALSA-clients that use jack via .asoundrc) and connects them to
  jack_mixer's input. jack.plumbing stays active permanently in my
  X-session.

My ruleset (.jack.plumbing) looks like:

(connect    "alsa-jack\..*jackP\..*:out_000" "jack_mixer:ALSA L")
(connect    "alsa-jack\..*jackP\..*:out_001" "jack_mixer:ALSA R")
(disconnect "alsa-jack\..*jackP\..*:out_000" "system:playback_1")
(disconnect "alsa-jack\..*jackP\..*:out_001" "system:playback_2")

(connect    "Clementine:out_jackaudiosink-.*_1" "jack_mixer:JACK L")
(connect    "Clementine:out_jackaudiosink-.*_2" "jack_mixer:JACK R")
(disconnect "Clementine:out_jackaudiosink-.*_1" "system:playback_1")
(disconnect "Clementine:out_jackaudiosink-.*_2" "system:playback_2")

(connect    "Qtractor:Master/out_1" "jack_mixer:JACK L")
(connect    "Qtractor:Master/out_2" "jack_mixer:JACK R")
(disconnect "Qtractor:Master/out_1" "system:playback_1")
(disconnect "Qtractor:Master/out_2" "system:playback_2")

(connect    "rosegarden:master out L" "jack_mixer:JACK L")
(connect    "rosegarden:master out R" "jack_mixer:JACK R")
(disconnect "rosegarden:master out L" "system:playback_1")
(disconnect "rosegarden:master out R" "system:playback_2")

(connect    "MPlayer.*:out_0" "jack_mixer:ALSA L")
(connect    "MPlayer.*:out_1" "jack_mixer:ALSA R")
(disconnect "MPlayer.*:out_0" "system:playback_1")
(disconnect "MPlayer.*:out_1" "system:playback_2")

(connect "jack_mixer:MAIN L" "system:playback_1")
(connect "jack_mixer:MAIN R" "system:playback_2")

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