Multithread app that just changes volume

[marcin at saepia.net]

Hi,

I am developing an application that does simple thing: Takes an audio
from pulseaudio (pulsesrc), process it (currently only using volume
element) and sends it back to the pulseaudio (pulsesink). pulsesrc and
pulsesink is separated by queue2 to avoid clock issues.

This app also connects itself to PulseAudio and D-Bus (GIO bindings),
both via GLib's mainloop.

The application logic is simple - it receives signal from D-Bus and
then performs fade in or fade out on the signal. To schedule fade
steps I use GLib's g_timeout_add().