PulseAudio

Revision as of 10:18, 11 September 2008

PulseAudio (homepage) is the sound server used by Openmoko to mix output from several applications as needed.

neod uses PulseAudio to play the samples "startup" and "touchscreen".

The samples are loaded from files and can be changed or disabled at the configuration file /etc/pulse/session.

Turning the Neo1973 into a USB sound card

The sound server can easily be made available (and discoverable, thanks to Avahi) in the local network, effectively turning the Neo1973 into an overqualified USB sound card (see also: http://www.pulseaudio.org/wiki/PerfectSetup):

opkg install pulseaudio-module-zeroconf-publish pulseaudio-module-native-protocol-tcp
echo "load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1;192.168.0.0/16" >> /etc/pulse/session
echo "load-module module-zeroconf-publish" >> /etc/pulse/session
/etc/init.d/pulseaudio restart

Now on a Desktop with PulseAudio properly set up, the padevchooser applet lists the Neo's hostname as audio sink as soon as it is connected via USB.

Pulseaudio takes 10% cpu time

Looking at the active processes with top, if pulseaudio appears to take 10% cpu time even when doing nothing:

opkg install pulseaudio-module-suspend-on-idle
echo "load-module module-suspend-on-idle" >> /etc/pulse/session
/etc/init.d/pulseaudio restart