PulseAudio

Last updated
PulseAudio
Developer(s)
  • Lennart Poettering
  • Pierre Ossman
  • Shahms E. King
  • Tanu Kaskinen
  • Colin Guthrie
  • Arun Raghavan
  • David Henningsson
Initial release17 July 2004;20 years ago (2004-07-17) [1]
Stable release
17.0 [2] / 12 January 2024;11 months ago (2024-01-12)
Repository gitlab.freedesktop.org/pulseaudio/pulseaudio
Written in C [3]
Operating system FreeBSD, NetBSD, OpenBSD, Linux, Illumos, Solaris, macOS, and Microsoft Windows (not maintained)
Platform ARM, PowerPC, x86 / IA-32, x86-64, and MIPS
Type Sound server
License LGPL-2.1-or-later [4]
Website pulseaudio.org

PulseAudio is a network-capable sound server program distributed via the freedesktop.org project. It runs mainly on Linux, including Windows Subsystem for Linux on Microsoft Windows and Termux on Android; various BSD distributions such as FreeBSD, OpenBSD, and macOS; as well as Illumos distributions and the Solaris operating system. It serves as a middleware in between applications and hardware and handles raw PCM audio streams. [5]

Contents

PulseAudio is free and open-source software, and is licensed under the terms of the LGPL-2.1-or-later. [4]

It was created in 2004 under the name Polypaudio but was renamed in 2006 to PulseAudio. [6]

PulseAudio competes with newer PipeWire, which provides a compatible PulseAudio server (known as pipewire-pulse), and PipeWire is now used by default on many Linux distributions, including Fedora Linux, Ubuntu, and Debian. [7] [8] [9]

Support for Microsoft Windows

On Microsoft Windows, PulseAudio runs in Windows Subsystem for Linux.

The NT kernel was previously supported via MinGW (an implementation of the GNU toolchain, which includes various tools such as GCC and binutils). The NT kernel port has not been updated since 2011, however. [10]

Software architecture

PulseAudio operational flow chart Pulseaudio-diagram.svg
PulseAudio operational flow chart
PulseAudio is a daemon that does mixing in software. Linux kernel and daemons with exclusive access.svg
PulseAudio is a daemon that does mixing in software.

In broad terms ALSA is a kernel subsystem that provides the sound hardware driver, and PulseAudio is the interface engine between applications and ALSA. However, its use is not mandatory and audio can still be played and mixed together without PulseAudio.

PulseAudio acts as a sound server, where a background process accepting sound input from one or more sources (processes, capture devices, etc.) is created. The background process then redirects these sound sources to one or more sinks (sound cards, remote network PulseAudio servers, or other processes). [11]

One of the goals of PulseAudio is to reroute all sound streams through it, including those from processes that attempt to directly access the hardware (like legacy OSS applications). PulseAudio achieves this by providing adapters to applications using other audio systems, like aRts and ESD.

In a typical installation scenario under Linux, the user configures ALSA to use a virtual device provided by PulseAudio. Thus, applications using ALSA will output sound to PulseAudio, which then uses ALSA itself to access the real sound card. PulseAudio also provides its own native interface to applications that want to support PulseAudio directly, as well as a legacy interface for ESD applications, making it suitable as a drop-in replacement for ESD.

For OSS applications, PulseAudio provides the padsp utility, which replaces device files such as /dev/dsp, tricking the applications into believing that they have exclusive control over the sound card. In reality, their output is rerouted through PulseAudio.

libcanberra

libcanberra is an abstract API for desktop event sounds and a total replacement for the "PulseAudio sample cache API":

libSydney

libSydney is a total replacement for the "PulseAudio streaming API", and plans have been made for libSydney to eventually become the only audio API used in PulseAudio. [15]

Features

The main PulseAudio features include: [11]

Adoption

PulseAudio first appeared for regular users in Fedora Linux, starting with version 8, [18] then was adopted by major Linux distributions such as Ubuntu, Debian, [19] Mandriva Linux, and openSUSE. There is support for PulseAudio in the GNOME project, and also in KDE, as it is integrated into Plasma Workspaces, adding support to Phonon (the KDE multimedia framework) and KMix (the integrated mixer application) as well as a "Speaker Setup" GUI to aid the configuration of multi-channel speakers. PulseAudio is also available in the Illumos distribution OpenIndiana, and enabled by default in its MATE desktop environment.

Various Linux-based mobile devices, including Nokia N900, Nokia N9 and the Palm Pre [20] use PulseAudio.

Tizen, an open-source mobile operating system, which is a project of the Linux Foundation and is governed by a Technical Steering Group (TSG) composed of Intel and Samsung, uses PulseAudio.

Problems during adoption phase

Other sound servers

JACK is a sound server that provides real-time, low-latency (i.e. 5 milliseconds or less) audio performance and, since JACK2, supports efficient load balancing by utilizing symmetric multiprocessing; that is, the load of all audio clients can be distributed among several processors. JACK is the preferred sound server for professional audio applications such as Ardour, ReZound, and LinuxSampler; multiple free audio-production distributions use it as the default audio server.

It is possible for JACK and PulseAudio to coexist: while JACK is running, PulseAudio can automatically connect itself as a JACK client, allowing PulseAudio clients to make and record sound at the same time as JACK clients. [36]

PipeWire is an audio and video server that "aims to support the use cases currently handled by both PulseAudio and Jack". [37] [38]

General audio infrastructures

Before JACK and PulseAudio, sound on these systems was managed by multi-purpose integrated audio solutions. These solutions do not fully cover the mixing and sound streaming process, but they are still used by JACK and PulseAudio to send the final audio stream to the sound card.

See also

Related Research Articles

<span class="mw-page-title-main">Linux distribution</span> Operating system based on the Linux kernel

A Linux distribution is an operating system that includes the Linux kernel for its kernel functionality. Although the name does not imply product distribution per se, a distro, if distributed on its own, is often obtained via a website intended specifically for the purpose. Distros have been designed for a wide variety of systems ranging from personal computers to servers and from embedded devices to supercomputers.

<span class="mw-page-title-main">Advanced Linux Sound Architecture</span> Software framework

Advanced Linux Sound Architecture (ALSA) is a software framework and part of the Linux kernel that provides an application programming interface (API) for sound card device drivers.

The Open Sound System (OSS) is an interface for making and capturing sound in Unix and Unix-like operating systems. It is based on standard Unix devices system calls. The term also sometimes refers to the software in a Unix kernel that provides the OSS interface; it can be thought of as a device driver for sound controller hardware. The goal of OSS is to allow the writing of sound-based applications that are agnostic of the underlying sound hardware.

JACK Audio Connection Kit is a professional sound server API and pair of daemon implementations to provide real-time, low-latency connections for both audio and MIDI data between applications. JACK was developed by a community of open-source developers led by Paul Davis and has been a key piece of infrastructure and the de facto standard for professional audio software on Linux since its inception in 2002. The server is free software, licensed under GPL-2.0-or-later, while the library is licensed under LGPL-2.1-or-later.

freedesktop.org (fd.o), formerly X Desktop Group (XDG), is a project to work on interoperability and shared base technology for free-software desktop environments for the X Window System (X11) and Wayland on Linux and other Unix-like operating systems. Although freedesktop.org produces specifications for interoperability, it is not a formal standards body.

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

Planet CCRMA Planet CCRMA software is a collection of open-source tools and applications designed for music composition, sound synthesis, and audio processing. It is primarily built on the Linux operating system and integrates various software packages, making it suitable for music researchers, composers, and educators. It is a collection of Red Hat packages to help set up and optimize a Red Hat-based workstation for audio work.

<span class="mw-page-title-main">Linux kernel interfaces</span> An overview and comparison of the Linux kernel API and ABI.

The Linux kernel provides multiple interfaces to user-space and kernel-mode code that are used for varying purposes and that have varying properties by design. There are two types of application programming interface (API) in the Linux kernel:

  1. the "kernel–user space" API; and
  2. the "kernel internal" API.

HAL is a software subsystem for UNIX-like operating systems providing hardware abstraction.

nouveau (software) Open source software driver for Nvidia GPU

nouveau is a free and open-source graphics device driver for Nvidia video cards and the Tegra family of SoCs written by independent software engineers, with minor help from Nvidia employees.

<span class="mw-page-title-main">Ubuntu Studio</span> Derivative of the Ubuntu operating system

Ubuntu Studio is a recognized flavor of the Ubuntu Linux distribution, which is geared to general multimedia production. The original version, based on Ubuntu 7.04, was released on 10 May 2007.

<span class="mw-page-title-main">Plymouth (software)</span> Graphical boot software for Linux

Plymouth is an application which provides a graphical boot experience for Linux. Plymouth supports animations using Direct Rendering Manager (DRM) and the KMS driver. Plymouth is bundled with an initial ramdisk which allows it to run before the file system is mounted. Some sources claim that Plymouth is named after Plymouth Rock, symbolizing the program's role as the first thing a user sees, but this has not been confirmed in any official capacity.

systemd Suite of system components for Linux

systemd is a software suite that provides an array of system components for Linux operating systems. The main aim is to unify service configuration and behavior across Linux distributions. Its primary component is a "system and service manager" — an init system used to bootstrap user space and manage user processes. It also provides replacements for various daemons and utilities, including device management, login management, network connection management, and event logging. The name systemd adheres to the Unix convention of naming daemons by appending the letter d. It also plays on the term "System D", which refers to a person's ability to adapt quickly and improvise to solve problems.

<span class="mw-page-title-main">Criticism of desktop Linux</span> Criticism of certain Linux distributions

Criticism of desktop Linux is a history of comment on the perceived shortcomings of the Linux operating system when installed on desktop computers. These criticisms have been aimed at the plethora of issues and lack of consistency between Linux distributions, their usefulness and ease of use as desktop systems for general end users, driver support and issues with multi-media playback and audio development.

<span class="mw-page-title-main">Lennart Poettering</span> German software engineer

Lennart Poettering is a German software engineer working for Microsoft and the original author of PulseAudio, Avahi and systemd.

WildMIDI is a free open-source software synthesizer which converts MIDI note data into an audio signal using GUS sound patches without need for a GUS patch-compatible soundcard. WildMIDI, whose aim is to be as small as possible and easily portable, started in December 2001, can act as a virtual MIDI device, capable of receiving MIDI data from any program and transforming it into audio on-the-fly. It is the standard MIDI renderer for the GStreamer framework.

firewalld is a firewall management tool for Linux operating systems. It provides firewall features by acting as a front-end for the Linux kernel's netfilter framework. firewalld's current default backend is nftables. Prior to v0.6.0, iptables was the default backend. Through its abstractions, firewalld acts as an alternative to nft and iptables command line programs. The name firewalld adheres to the Unix convention of naming system daemons by appending the letter "d".

<span class="mw-page-title-main">LDAC (codec)</span> Digital audio encoding technology

LDAC is a proprietary audio coding technology developed by Sony, which allows streaming high-resolution audio over Bluetooth connections at up to 990 kbps at 32 bits/96 kHz. It is used by various products, including headphones, earphones, smartphones, portable media players, active speakers, and home theaters.

<span class="mw-page-title-main">PipeWire</span> Media processing server for Linux

PipeWire is a server for handling audio, video streams, and hardware on Linux. It was created by Wim Taymans at Red Hat. It handles multimedia routing and pipeline processing.

References

  1. ↑ "OldNews". freedesktop.org.
  2. ↑ "PulseAudio 17.0 · PulseAudio / pulseaudio · GitLab". GitLab. Retrieved 13 January 2024.
  3. ↑ "PulseAudio", Analysis Summary, Open Hub
  4. 1 2 "License", PulseAudio git, Free desktop, archived from the original on 4 March 2014, retrieved 16 June 2011
  5. ↑ "SupportedAudioFormats". www.freedesktop.org. Retrieved 13 May 2023.
  6. ↑ The Project Formerly Known as Polypaudio
  7. ↑ "Changes/DefaultPipeWire - Fedora Project Wiki". fedoraproject.org. Retrieved 13 February 2023.
  8. ↑ Sneddon, Joey (22 May 2022). "Ubuntu 22.10 Makes PipeWire Default for Audio". OMG! Ubuntu!. Retrieved 13 February 2023.
  9. ↑ "Debian 12 Switches To PipeWire & WirePlumber By Default With The GNOME Desktop". www.phoronix.com. Retrieved 13 February 2023.
  10. ↑ PulseAudio on Windows
  11. 1 2 "About", PulseAudio, Free desktop, retrieved 11 March 2013
  12. ↑ "Debian -- Package Search Results -- libcanberra". packages.debian.org.
  13. ↑ "Debian -- Package Search Results -- libasound". packages.debian.org.
  14. ↑ "Debian -- Package Search Results -- libcanberra-pulse". packages.debian.org.
  15. ↑ Poettering, Lennart (8 February 2007). "FOMS/LCA Recap". 0pointer.de. Retrieved 13 March 2017.
  16. ↑ Poettering, Lennart, "Interviews", Fedora Project, Red Hat, retrieved 3 July 2009
  17. ↑ Pulse Audio wiki, PulseAudio, archived from the original on 31 August 2009, retrieved 19 July 2009
  18. ↑ "LPC: Linux audio: it's a mess [LWN.net]". 18 September 2008. Retrieved 11 July 2019.
  19. ↑ PulseAudio, Debian, archived from the original (wiki) on 9 November 2013, retrieved 9 November 2013
  20. ↑ "Open source identity: PulseAudio creator Lennart Poettering", TechWorld, 8 October 2009
  21. ↑ Poettering, Lennart (25 September 2004). "Writing a PortAudio driver". audio.portaudio.devel. git.net. Retrieved 28 February 2017.
  22. ↑ Poettering, Lennart. "PulseAudio is now enabled by default on new Fedora installs". Fedora Development ML. Red Hat. Retrieved 1 March 2017.
  23. ↑ "Features: Glitch-free Audio". Fedora Project Wiki. Retrieved 28 February 2017.
  24. ↑ Poettering, Lennart. "Alsa Issues". PulseAudio - Trac. Archived from the original on 16 October 2008. Retrieved 28 February 2017.
  25. ↑ LPC: Linux audio: it's a mess, LWN, 18 September 2008, archived from the original on 1 September 2009, retrieved 3 July 2009
  26. ↑ Lennart Poettering (18 July 2008), PulseAudio FUD, 0pointer.de, archived from the original on 2 September 2009, retrieved 30 December 2009
  27. ↑ How-to: PulseAudio Fixes & System-Wide Equalizer Support, Ubuntu Forums, 10 May 2008, archived from the original on 1 March 2010, retrieved 18 October 2009
  28. ↑ I'll Break Your Audio, Lennart Poettering Blog, 19 October 2009, retrieved 26 December 2009
  29. ↑ No sound after running Flash, YouTube, etc. (pulseaudio solution), Ubuntu Forums, archived from the original on 29 February 2012, retrieved 18 October 2009
  30. ↑ PulseAudio, Ubuntu Wiki, archived from the original on 25 February 2011, retrieved 18 October 2009
  31. ↑ "Over-optimistic buffering in PulseAudio causes underruns (audible stuttering, pops)". Launchpad. 10 February 2008. Retrieved 9 November 2013.
  32. ↑ "46466 - PulseAudio needs a way for the user to set inviolable maximum volume". Bugzilla. Retrieved 6 October 2021.
  33. ↑ "[SOLVED] disabling pulseaudio - Page 3". Linux Questions. Retrieved 6 October 2021.
  34. ↑ "Bug #410948 'Volume too loud' : Bugs : pulseaudio package". Ubuntu. 9 August 2009. Retrieved 6 October 2021.
  35. ↑ "#837637 - Audio settings often reset to 100% Volume". Debian Bug report logs. Retrieved 6 October 2021.
  36. ↑ See “Loadable Modules.” Modules, Freedesktop.org, https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Modules/#index9h2, retrieved August 28, 2019
  37. ↑ "PipeWire". pipewire.org.
  38. ↑ "On the Road to Fedora Workstation 31 — Christian F.K. Schaller". 24 June 2019.
  39. ↑ An introduction to Linux sound systems and APIs, Linux.com, 9 August 2004, archived from the original on 19 October 2014, retrieved 23 March 2013, OSS is available not only for Linux but also for BSD OSes and other Unixes. That may be its only advantage, because this system is not very powerful and was officially replaced by ALSA in 2.5 kernels...
  40. ↑ 4Front technologies releases the source code for open sound system, Linux PR, 14 June 2007, archived from the original on 8 October 2007, retrieved 8 January 2012{{citation}}: CS1 maint: unfit URL (link).

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.