PulseAudio

Polypaudio is a cross-platform networked sound server project. It is a free software and the first release came out in July, 2004, under the LGPL. Works under Linux and other Unix like operating systems and Microsoft Windows. It is intended to be an improved drop-in replacement for the Enlightened Sound Daemon (ESOUND). The main Polypaudio features include:

    * An extensible plugin architecture with support for loadable modules.
    * Compatibility with many popular audio applications.
    * Support for multiple audio sources and sinks.
    * Low-latency operation and support for latency measurement.
    * A zero-copy memory architecture for processor resource efficiency.
    * A command-line interface with scripting capabilities.
    * A sound daemon with command line reconfiguration capabilities.
    * Built-in sample conversion and resampling capabilities.
    * The ability to combine multiple sound cards into one.
    * The ability to synchronize multiple playback streams.