Running ALSA applications with FFADO

Once you have your jackd running with FFADO, you would probably also like to use some non-jackd applications, i.e. sound from the flash plugin (Update: if you want jack-enabled flash, try git clone git://repo.or.cz/libflashsupport-jack.git) in your browser. While it's usually possible to configure programs like mplayer, qmmp or gstreamer to use jackd directly, you cannot do so with others (once again: flash).

According to http://alsa.opensrc.org/index.php/Jack_(plugin), there's a way to reroute the ALSA output to jackd. On Debian-based systems, you'd need to install libasound2-plugins, other distros may vary:

# apt-get install libasound2-plugins

Afterwards, change your ~/.asoundrc:

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

pcm.jack {
    type jack
    playback_ports {
        0 system:playback_1
        1 system:playback_2
    }

    capture_ports {
        0 alsa_pcm:capture_1
        1 alsa_pcm:capture_2
    }
}

ctl.mixer0 {
    type hw
    card 0
}

Note that you don't have to provide target names for the playback ports. If you prefer to start your alsa application without connecting to system:playback_1, just omit them, but keep the channel numbers (0,1):

pcm.jack {
    type jack
    playback_ports {
        0
        1
    }
[..]

If you need to automatically connect one channel to more than one jackd destination port, then take an approach as outlined in http://www.alsa-project.org/main/index.php/Asoundrc#Virtual_multi_channel_devices. Of course, you could still create multiple connections of the same output by hand (e.g. in qjackctl)

OSS-only applications

If you have old applications which neither support jackd nor ALSA, you need to use an OSS wrapper on top of ALSA. On Debian-based systems, install alsa-oss:

# apt-get install alsa-oss

This should give you the wrapper script aoss, making OSS applications use ALSA and hence jackd, if configured as shown above. For Firefox/Flash, there's nothing more to do, for all other apps see http://alsa.opensrc.org/Aoss.