Jack (plugin)
From the ALSA wiki
In short, you can set up your asoundrc file to specify JACK as the output, like so:
pcm.!default {
type plug
slave { pcm "jack" }
}
pcm.jack {
type jack
playback_ports {
0 alsa_pcm:playback_1
1 alsa_pcm:playback_2
}
capture_ports {
0 alsa_pcm:capture_1
1 alsa_pcm:capture_2
}
}
ctl.mixer0 {
type hw
card 0
}
Then, after starting jackd with the appropriate sample rate for what you're doing, you can use ALSA apps with JACK:
jackd -d alsa -d hw:0 -r 44100 aplay -D pcm.jack <filename>
This will direct the ALSA playback stream (from aplay) visible to your JACK application, rather than sending it directly to the sound card.
Non-ALSA JACK audio I/O (e.g. FreeBOB)
If jackd is using an audio driver other than ALSA (as in FreeBOB, for example), the port names in the pcm.jack definition will be different from the example above. Run jack_lsp to list the port names, for example:
$ jack_lsp system:capture_1 system:capture_2 system:capture_3 system:capture_4 system:capture_5 system:capture_6 system:playback_1 system:playback_2 system:playback_3 system:playback_4 system:playback_5 system:playback_6 system:playback_7 system:playback_8
You can then use the appropriate port names in your .asoundrc, e.g.
pcm.jack {
type jack
playback_ports {
0 system:playback_1
1 system:playback_2
}
capture_ports {
0 system:capture_1
1 system:capture_2
}
}
