PulseAudio
Related articles
PulseAudio is a sound server commonly used by desktop environments like GNOME or KDE. It serves as a proxy to sound applications using existing kernel sound components like ALSA or OSS. Since ALSA is included in Arch Linux by default, the most common deployment scenarios include PulseAudio with ALSA.
Contents
Installation
- Required package: pulseaudio
- Optional GTK GUIs: paprefs and pavucontrol
- Optional volume control via mapped keyboard keys: pulseaudio-ctl
- Optional console (CLI) mixers: ponymix and pamixer-git
- Optional web volume control: PaWebControl
- Optional system tray icon: pasystray-git
- Optional KDE plasma applet: kdemultimedia-kmix and kdeplasma-applets-veromix (If KMix/Veromix fail to connect to PulseAudio at boot you may need to edit
/etc/pulse/client.conf
to includeautospawn = yes
instead ofautospawn = no
.)
Configuration
Configuration files
By default, PulseAudio is configured to automatically detect all sound cards and manage them. It takes control of all detected ALSA devices and redirect all audio streams to itself, making the PulseAudio daemon the central configuration point. The daemon should work mostly out of the box, only requiring a few minor tweaks.
PulseAudio will first look for configuration files in home directory ~/.config/pulse
, then in system wide /etc/pulse
.
PulseAudio runs as a server daemon that can run either system-wide or on per-user basis using a client/server architecture. The daemon by itself does nothing without its modules except to provide an API and host dynamically loaded modules. The audio routing and processing tasks are all handled by various modules. You find a detailed list of all available modules at Pulseaudio Loadable Modules. To enable them you can just add a line load-module <module-name-from-list>
to ~/.config/pulse/default.pa
.
daemon.conf
It defines base settings like the default sample rates used by modules, resampling methods, realtime scheduling and various other settings related to the server process. These can not be changed at runtime without restarting the PulseAudio daemon. Most defaults make sense here.
Option | Description | system-instance | If set to yes , the daemon will run as a system-wide instance. Highly discouraged as it can introduce security issues. Can be used when multiple users will use sound at the same time, either remotely or locally using Xorg_multiseat. Defaults to no .
|
resample-method | When PulseAudio needs to pass audio from one module to another using incompatible sample-rate (for example, playback at 96kHz to a card that only supports a maximum of 48kHz), specifies which resampler to use. You can use the command $ pulseaudio --dump-resample-methods to list all available resamplers and choose the best tradeoff between CPU usage and audio quality for your taste.
|
flat-volumes | If yes (default), all input sources have their volume relative to the maximum volume of the entire sound card. This allows each application to individually adjust their volume so for example, raising your VoIP call volume will raise the hardware volume and adjust your music player volume so it stays where it was, avoiding confusion by having to lower manually the music player then raise the global volume.
|
default-fragments | Audio samples are splitted into multiple fragments of default-fragment-size-msec each. The larger the buffer is, the less likely audio will skip when the system is overloaded, but will also increase the overall latency. Increase this value if you have issues.
|
---|
default.pa
This file is a startup script and is used to configure modules. It is actually parsed and read after the daemon has finished initializing and additionnal commands can be sent at runtime using $ pactl
or $ pacmd
. The startup script can also be provided on the command line by starting PulseAudio in a terminal using $ pulseaudio -nC
. This will make the daemon load the CLI module and will accept the configuration directly from the command line, and output resulting information or error messages on the same terminal. This can be useful when debugging the daemon or just to test various modules before setting them permanently on disk. The manual page is quite self explaining, please consult man pulse-cli-syntax
for the details of the syntax.
client.conf
This is the configuration file read by every PulseAudio client applications. It is used to configure runtime options for individual clients. It can be used to set the configure the default sink and source statically as well as allowing (or disallowing) clients to automatically start the server if not currently running.
Configuration command
The main command to configure a server during runtime is $ pacmd
. Run $ pacmd --help
for a list options, or just run $ pacmnd
to enter the shell interactive mode and Ctrl+d
to exit. All modifications will immediately be applied.
Once your new settings have been tested and meet your needs, edit the default.pa
accordingly to make the change persistent. See PulseAudio/Examples for some basic settings.
It is important to understand that the "sources" and "sinks" accessible and selectable through PulseAudio depend upon the current hardware "Profile" selected. These "Profiles" are those ALSA "pcms" listed by the command aplay -L
, and more specifically by the command pacmd list-cards
, which will include a line "index:", a list beginning "profiles:", and a line "active profile: <...>" in the output, among other things.
The "active profile" can be set with the command pacmd set-card-profile INDEX PROFILE
, with no comma separating INDEX and PROFILE, where INDEX is just the number on the line "index:" and a PROFILE name is everything shown from the beginning of any line under "profile:" to just before the colon and first space, as shown by the command pacmd list-cards
. For instance, pacmd set-card-profile 0 output:analog-stereo+input:analog-stereo
.
It may be easier to select a "Profile" with a graphical tool like pavucontrol
, under the "Configuration" tab, or KDE System Settings, "Multimedia/Audio and Video Settings", under the "Audio Hardware Setup" tab. Each audio "Card", which are those devices listed by the command aplay -l
, or again by the command pacmd list-cards
, will have its own selectable "Profile". When a "Profile" has been selected, the then available "sources" and "sinks" can be seen by using the commands pacmd list-sources
and pacmd list-sinks
. Note that the "index" of the available sources and sinks will change each time a card profile is changed.
The selected "Profile" can be an issue for some applications, especially the Adobe Flash players, typically /usr/lib/mozilla/plugins/libflashplayer.so
and /usr/lib/PepperFlash/libpepflashplayer.so
. Often, these Flash players will only work when one of the Stereo profiles is selected, and otherwise, will play video with no sound, or will simply "crash". When all else fails, you might try selecting a different profile.
Of course, when configuring some variation of Surround Sound in PulseAudio, the appropriate Surround profile will have to be selected, before Surround Sound will work, or in order to do things like remap the speaker channels.
Running
In the unlikely event that PulseAudio is not automatically started upon entering X, it can can be started with:
$ pulseaudio --start
PulseAudio can be stopped with:
$ pulseaudio --kill
If the line autospawn=no
exists in either /etc/pulse/client.conf
or ~/.pulse/client.conf
, you may need to change it to autospawn=yes
and restart.
Autostarting in unsupported desktop environments
Check to see if PulseAudio is running:
$ pgrep -af pulseaudio
369 /usr/bin/pulseaudio
If PulseAudio is not running and users are using X, the following will start PulseAudio with the needed the X11 plugins manually:
$ start-pulseaudio-x11
If you are running a DM or DE that doesn't support autostarting from /etc/xdg/autostart/
, then you can launch PulseAudio on login through ~/.xprofile
(Some older DMs may require this to be placed in ~/.xinitrc
instead):
~/.xprofile
/usr/bin/start-pulseaudio-x11 &
Back-end configuration
ALSA
Install pulseaudio-alsa from the official repositories. This package contains the necessary /etc/asound.conf
for configuring ALSA to use PulseAudio.
Also install lib32-libpulse and lib32-alsa-plugins if you run a x86_64 system and want to have sound for 32-bit multilib programs like Wine, Skype and Steam.
To prevent applications from using ALSA's OSS emulation and bypassing PulseAudio (thereby preventing other applications from playing sound), make sure the module snd_pcm_oss
is not being loaded at boot. If it is currently loaded (lsmod | grep oss
), disable it by executing:
# rmmod snd_pcm_oss
ALSA/dmix without grabbing hardware device
You may want to use ALSA directly in most of your applications and to be able to use other applications, which constantly require PulseAudio at the same time. The following steps allow you to make PulseAudio use dmix instead of grabbing ALSA hardware device.
- Remove package pulseaudio-alsa, which provides compatibility layer between ALSA applications and PulseAudio. After this your ALSA apps will use ALSA directly without being hooked by Pulse.
- Edit
/etc/pulse/default.pa
.
- Find and uncomment lines which load back-end drivers. Add device parameters as follows. Then find and comment lines which load autodetect modules.
load-module module-alsa-sink device=dmix load-module module-alsa-source device=dsnoop # load-module module-udev-detect # load-module module-detect
- Optional: If you use kdemultimedia-kmix you may want to control ALSA volume instead of PulseAudio volume:
$ echo export KMIX_PULSEAUDIO_DISABLE=1 > ~/.kde4/env/kmix_disable_pulse.sh $ chmod +x ~/.kde4/env/kmix_disable_pulse.sh
- Now, reboot your computer and try running ALSA and PulseAudio applications at the same time. They both should produce sound simultaneously.
- Use pavucontrol to control PulseAudio volume if needed.
Bluetooth Audio
Install pavucontrol to select the Output Device as well as direct the Playback app to the correct bluetooth audio device.
OSS
There are multiple ways of making OSS-only programs output to PulseAudio:
ossp
Install ossp package and start osspd.service
.
padsp wrapper
Programs using OSS can work with PulseAudio by starting it with padsp (included with PulseAudio):
$ padsp OSSprogram
A few examples:
$ padsp aumix $ padsp sox foo.wav -t ossdsp /dev/dsp
You can also add a custom wrapper script like this:
/usr/local/bin/OSSProgram
#!/bin/sh exec padsp /usr/bin/OSSprogram "$@"
Make sure /usr/local/bin
comes before /usr/bin
in your PATH.
GStreamer
Install gst-plugins-good, or gstreamer0.10-good-plugins if your intended program has a legacy GStreamer implementation.
OpenAL
OpenAL Soft should use PulseAudio by default, but can be explicitly configured to do so:/etc/openal/alsoft.conf
drivers=pulse,alsa
libao
Edit the libao configuration file:
/etc/libao.conf
default_driver=pulse
Be sure to remove the dev=default
option of the alsa driver or adjust it to specify a specific Pulse sink name or number.
Equalizer
PulseAudio has an integrated 10-band equalizer system. In order to use the equalizer do the following:
Load equalizer sink and dbus-protocol module
$ pactl load-module module-equalizer-sink $ pactl load-module module-dbus-protocol
Install and run the GUI front-end
Install python-pyqt4 and execute:
$ qpaeq
Load equalizer and dbus module on every boot
Edit the /etc/pulse/default.pa
or ~/.config/pulse/default.pa
file with your favorite editor and append the following lines:
### Load the integrated PulseAudio equalizer and D-Bus module load-module module-equalizer-sink load-module module-dbus-protocol
Applications
QEMU
The audio driver used by QEMU is set with the QEMU_AUDIO_DRV
environment variable:
$ export QEMU_AUDIO_DRV=pa
Run the following command to get QEMU's configuration options related to PulseAudio:
$ qemu-system-x86_64 -audio-help | awk '/Name: pa/' RS=
The listed options can be exported as environment variables, for example:
$ export QEMU_PA_SINK=alsa_output.pci-0000_04_01.0.analog-stereo.monitor $ export QEMU_PA_SOURCE=input
To get list of the supported emulation audio drivers
$ qemu-system-x86_64 -soundhw help
To use e.g. ac97
driver for the guest use the -soundhw ac97
commnad with QEMU.
AlsaMixer.app
Make alsamixer.app dockapp for the windowmaker use pulseaudio, e.g.
$ AlsaMixer.app --device pulse
Here is a two examples where the first one is for ALSA and the other one is for pulseaudio. You can run multiple instances of it. Use the -w
option to choose which of the control buttons to bind to the mouse wheel.
# AlsaMixer.app -3 Mic -1 Master -2 PCM --card 0 -w 1 # AlsaMixer.app --device pulse -1 Capture -2 Master -w 2
XMMS2
Make it switch to pulseaudio output
$ nyxmms2 server config output.plugin pulse
and to alsa
$ nyxmms2 server config output.plugin alsa
To make xmms2 use a different output sink, e.g.
$ nyxmms2 server config pulse.sink alsa_output.pci-0000_04_01.0.analog-stereo.monitor
See also the official guide [1].
KDE Plasma Workspaces and Qt4
PulseAudio will automatically be used by KDE/Qt4 applications. It is supported by default in the KDE sound mixer. For more information see the KDE page in the PulseAudio wiki. One useful tidbit from that page is to add load-module module-device-manager
to /etc/pulse/default.pa
.
If the phonon-gstreamer backend is used for Phonon, GStreamer should also be configured as described in #GStreamer.
Audacious
Audacious natively supports PulseAudio. In order to use it, set Audacious Preferences -> Audio -> Current output plugin to 'PulseAudio Output Plugin'.
Java/OpenJDK 6
Create a wrapper for the Java executable using padsp as seen on the Java sound with PulseAudio page.
Music Player Daemon (MPD)
configure MPD to use PulseAudio. See also MPD/Tips and Tricks#MPD and PulseAudio.
MPlayer
MPlayer natively supports PulseAudio output with the -ao pulse
option. It can also be configured to default to PulseAudio output, in ~/.mplayer/config
for per-user, or /etc/mplayer/mplayer.conf
for system-wide:
/etc/mplayer/mplayer.conf
ao=pulse
guvcview
guvcview when using the PulseAudio input from a Webcam may have the audio input suspended resulting in no audio being recorded. You can check this by executing:
$ pactl list sources
If the audio source is "suspended" then modifying the following line in /etc/pulse/default.pa
and changing:
load-module module-suspend-on-idle
to
#load-module module-suspend-on-idle
And then either restarting PulseAudio or your computer will only idle the input source instead of suspending it. guvcview will then correctly record audio from the device.
Troubleshooting
See PulseAudio/Troubleshooting.
See also
- http://www.alsa-project.org/main/index.php/Asoundrc - ALSA wiki on .asoundrc
- http://www.pulseaudio.org/ - PulseAudio official site
- http://www.pulseaudio.org/wiki/FAQ - PulseAudio FAQ