General purpose sound server

PulseAudio is a layer between audio devices and applications. It removes
the need for applications to care about the details of the hardware.
PulseAudio is responsible for:
 * automatically converting the audio format between applications and sound
   devices
 * mixing audio streams, which allows multiple applications to use the same
   sound device at the same time
 * handling device and application volumes
 * routing audio to the right place without requiring applications to care
   about the routing
 * providing an unified view of all audio devices, regardless of whether
   they are ALSA-supported sound cards, Bluetooth headsets, remote sound
   cards in the local network or anything else
 * and more...