[Jack-Devel] Suggestion to include loopback capability in a Jack session

Fons Adriaensen fons at linuxaudio.org
Sun Jan 1 16:32:55 CET 2017

On Sat, Dec 31, 2016 at 03:26:17AM +0000, Thomas Howe wrote:

> This time it's not an impossible-to-reproduce bug, but a feature request!
> Let me know it there's a better place to post this. I think similar things
> have been suggested before, but this idea for a 'loopback' client hasn't as
> far as I'm aware.

ALSA's 'jack' plugin can route audio from an ALSA-aware app to
jack. You can specify to which jack ports it should connect.

You need the alsa-plugins package and an .asoundrc file in your
home directory. This works by making the jack plugin the default
ALSA device. In the example below it will connect to zita-mu1 for
output. I'm using this with Opera, works perfectly.

Example .asoundrc:

pcm.!default {
    type plug
    slave { pcm "jack" }

pcm.jack {
    type jack
    playback_ports {
       0 zita-mu1:in_2.L
       1 zita-mu1:in_2.R
    capture_ports {
        0 system:capture_1
        1 system:capture_2



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It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)

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