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.
[edit] 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. With jackd running, run jack_lsp to find out 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
}
}
