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.

