Libao is a cross-platform audio library that allows programs to output audio using a simple API on a wide variety of platforms. It currently supports: . * Null output (handy for testing without a sound device) * WAV files * AU files * OSS (Open Sound System, used on Linux and FreeBSD) * ALSA (Advanced Linux Sound Architecture) * PulseAudio (next generation GNOME sound server) * esd (EsounD or Enlightened Sound Daemon) * and several others.