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sound server

{{Short description|Software that manages audio devices}}

{{About|a form of computer program that runs in the background|computers that stream audio over a network|media server}}

{{inline |date=January 2025}}

A sound server is software that manages the use of and access to audio devices (usually a sound card). It commonly runs as a background process.

Sound server in an operating system

File:Soundserver eng.png

In a Unix-like operating system, a sound server mixes different data streams (usually raw PCM audio) and sends out a single unified audio to an output device. The mixing is usually done by software, or by hardware if there is a supported sound card.

=Layers=

The "sound stack" can be visualized as follows, with programs in the upper layers calling elements in the lower layers:

  • Applications (e.g. mp3 player, web video)
  • Sound server (e.g. aRts, ESD, JACK, PulseAudio)
  • Sound subsystem (described as kernel modules or drivers; e.g. OSS, ALSA)
  • Operating system kernel (e.g. Linux, Unix)

= Motivation =

Sound servers appeared in Unix-like operating systems after limitations in Open Sound System were recognized. OSS is a basic sound interface that was incapable of playing multiple streams simultaneously, dealing with multiple sound cards, or streaming sound over the network.

A sound server can provide these features by running as a daemon. It receives calls from different programs and sound flows, mixes the streams, and sends raw audio out to the audio device.

With a sound server, users can also configure global and per-application sound preferences.

= Diversification and problems =

{{As of | 2012}} there are multiple sound servers; some focus on providing very low latency, while others concentrate on features suitable for general desktop systems. While diversification allows a user to choose just the features that are important to a particular application, it also forces developers to accommodate these options by necessitating code that is compatible with the various sound servers available. Consequently, this variety has resulted in a desire for a standard API to unify efforts.

List of sound servers

= Streaming =

References

External links

  • [http://www.osnews.com/story.php?news_id=6720&page=2 Introduction to Linux Audio]
  • [http://mail.gnome.org/archives/gnome-multimedia/2001-May/msg00002.html RFC: GNOME 2.0 Multimedia strategy]

Category:Servers (computing)