Difference between revisions of "PulseAudio"

Latest revision as of 20:45, 21 June 2017

Installation

Install the pulseaudio package.

Some PulseAudio modules have been split from the main package and must be installed separately if needed:

pulseaudio-bluetooth: Bluetooth (Bluez) support
pulseaudio-equalizer: Equalizer sink (qpaeq)
pulseaudio-gconf: GConf support (paprefs)
pulseaudio-jack: JACK sink, source and jackdbus detection
pulseaudio-lirc: Infrared (LIRC) volume control
pulseaudio-zeroconf: Zeroconf (Avahi/DNS-SD) support

Note: Some confusion can be made between ALSA and PulseAudio. ALSA includes both Linux kernel component with sound card drivers, and a userspace component, libalsa.[1] PulseAudio builds only on the kernel component, but offers compatibility with libalsa through pulseaudio-alsa.[2]

Front-ends

There are a number of front-ends available for controlling the PulseAudio daemon:

GTK GUIs: paprefs and pavucontrol
Volume control via mapped keyboard keys: pulseaudio-ctl^AUR, pavolume-git^AUR
Console (CLI) mixers: ponymix and pamixer
Console (curses) mixer: pulsemixer^AUR
Web volume control: PaWebControl
System tray icon: pasystray^AUR, pasystray-git^AUR
KF5 plasma applet: kmix and plasma-pa
Xfce4 plugin: xfce4-pulseaudio-plugin, pa-applet-git^AUR
If you want to use Bluetooth Headsets or other Bluetooth Audio Devices together with PulseAudio see the Bluetooth headset Article.

Configuration

Configuration files

This article or section is a candidate for merging with PulseAudio/Configuration.

Notes: Configuration should stay in the main article, so the linked page should be merged here. Split #Troubleshooting instead if this page is found too long. (Discuss in Talk:PulseAudio#Abandoned draft)

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 can 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.

Tip:

It is strongly suggested not to edit system wide configuration files, but rather edit user ones. Create the ~/.config/pulse directory, then copy the system configuration files into it and edit according to your need.
Make sure you keep user configuration in sync with changes to the packaged files in /etc/pulse/. Otherwise, PulseAudio may refuse to start due to configuration errors.
There is usually no need to add your user to the audio group, as PulseAudio uses udev and logind to give access dynamically to the currently "active" user. Exceptions would include running the machine headless so that there is no currently "active" user.

daemon.conf

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. The defaults are sensible for most users.

Note: PulseAudio does not perform tilde expansion on paths in this file. Use absolute paths for any files.

Notable configuration options
Option	Description
system-instance	Run the daemon as a system-wide instance. Highly discouraged as it can introduce security issues. Useful on (headless) systems that have no real local users. Defaults to `no`.
resample-method	Which resampler to use when audio with incompatible sample rates needs to be passed between modules (e.g. playback of 96kHz audio on hardware which only supports 48kHz). The available resamplers can be listed with `$ pulseaudio --dump-resample-methods`. Choose the best tradeoff between CPU usage and audio quality for the present use-case. Tip: In some cases PulseAudio will generate a high CPU load. This can happen when multiple streams are resampled (individually). If this is a common use-case in a workflow, it should be considered to create an additional sink at a matching sample rate which can then be fed into the main sink, resampling only once.
flat-volumes	`flat-volumes` scales the device-volume with the volume of the "loudest" application. For example, raising the VoIP call volume will raise the hardware volume and adjust the music-player volume so it stays where it was, without having to lower the volume of the music-player manually. Defaults to `yes` upstream, but to `no` within Arch. Note: The default behavior upstream can sometimes be confusing and some applications, unaware of this feature, can set their volume to 100% at startup, potentially blowing your speakers or your ears. This is why Arch defaults to the classic (ALSA) behavior by setting this to `no`.
default-fragments	Audio samples are split 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. On the downside this will 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 additional 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-explanatory, consult man pulse-cli-syntax for the details of the syntax.

Tip:

Rather than being a complete copy, ~/.config/pulse/default.pa can start with the line .include /etc/pulse/default.pa and then just override the defaults.
Run $ pacmd list-sinks|egrep -i 'index:|name:' to list available sinks. The present default sink is marked with an asterisk.
Edit ~/.config/pulse/default.pa to insert/alter the set-default-sink command using the sink's name as the numbering cannot be guaranteed repeatable.

client.conf

This is the configuration file read by every PulseAudio client application. It is used to configure runtime options for individual clients. It can be used to set and 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 $ pacmd 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.

Tip: leave the load-module module-default-device-restore line in the default.pa file untouched. It will allow you to restart the server in its default state, thus dismissing any wrong setting.

It is important to understand that the "sources" (processes, capture devices) and "sinks" (sound cards, servers, other processes) 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

PulseAudio on Arch has pulseaudio.socket enabled by default for the systemd/User instance. This means that PulseAudio will automatically start when needed.

Note:

To disable pulseaudio.socket, make sure that $XDG_CONFIG_HOME/systemd/user/ exists and run systemctl --user mask pulseaudio.socket.
Many desktop environments autostart programs based on desktop files in the /etc/xdg/autostart/ directory. In this case, PulseAudio will be launched automatically regardless of the socket activation status.

For more information, see PulseAudio: Running.

Back-end configuration

ALSA

If you have applications that do not support PulseAudio explicitly but rely on ALSA, these applications will try to access the sound card directly via ALSA and will therefore bypass PulseAudio. PulseAudio will thus not have access to the sound card any more. As a result, all applications relying on PulseAudio will not be working any more, leading to this issue. To prevent this, you will need to install the pulseaudio-alsa package. It contains the necessary /etc/asound.conf for configuring ALSA to use PulseAudio. Also make sure that ~/.asoundrc does not exist, it would override the /etc/asound.conf file.

Please 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 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

Expose PulseAudio sources, sinks and mixers to ALSA

Although pulseaudio-alsa contains the necessary configuration file to allow ALSA applications to use PulseAudio's default device, ALSA's pulse plugin is more versatile than that:

~/.asoundrc (or /etc/asound.conf)

# Create an alsa input/output using specific PulseAudio sources/sinks
 pcm.pulse-example1 {
     type pulse
     device "my-combined-sink" # name of a source or sink
     fallback "pulse-example2" # if combined not available
 }
 
 pcm.pulse-example2 {
     type pulse
     device "other-sound-card" # name of a source or sink
     # example: device "alsa_output.pci-0000_00_1b.0.analog-stereo"
 }
 
 # Create an alsa mixer using specific PulseAudio sources/sinks
 # these can be tested with "alsamixer -D pulse-example3"
 ctl.pulse-example3 {
     type pulse
     device "my-output" # name of source or sink to control
 
     # example: always control the laptop speakers:
     # device "alsa_output.pci-0000_00_1b.0.analog-stereo"
     fallback "pulse-example4" # supports fallback too
 }
 
 # Mixers also can control a specific source and sink, separately:
 ctl.pulse-example4 {
     type pulse
     sink "my-usb-headphones"
     source "my-internal-mic"
     
     # example: output to HDMI, record using internal
     sink "alsa_output.pci-0000_01_00.1.hdmi-stereo-extra1"
     source "alsa_input.pci-0000_00_1b.0.analog-stereo"
 }
 
 # These can override the default mixer (example: for pnmixer integration)
 ctl.!default {
     type pulse
     sink "alsa_output.pci-0000_01_00.1.hdmi-stereo-extra1"
     source "alsa_input.pci-0000_00_1b.0.analog-stereo"
 }

The source code can be read to know all available options.

ALSA/dmix without grabbing hardware device

Note: This section describes alternative configuration, which is generally not recommended.

You may want to use ALSA directly in most of your applications while still being able to use applications which 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.

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^AUR 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.

Note: You could possibly also keep the libao standard of outputting to the alsa driver and its default device if you install pulseaudio-alsa since the ALSA default device then is PulseAudio.

Equalizer

Warning: The equalizer module is considered unstable and might be removed from PulseAudio. For more, see the mailing list.

PulseAudio has an integrated 10-band equalizer system. In order to use the equalizer do the following:

Install pulseaudio-equalizer:

Load equalizer sink and dbus-protocol module

$ pactl load-module module-equalizer-sink
$ pactl load-module module-dbus-protocol

GUI front-end

run:

$ qpaeq

Note: If qpaeq has no effect, install pavucontrol and change "ALSA Playback on" to "FFT based equalizer on ..." while the media player is running.

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

Note: The equalizer sink needs to be loaded after the master sink is already available.

Alternative equalizers

pulseaudio-equalizer-ladspa^AUR (based on swh-plugins) can be used as an alternative to pulseaudio-equalizer.

pulseeffects^AUR applies peak limiting, compression, reverberation, auto volume and 15 bands equalization to Pulseaudio applications output.

Applications

QEMU

Refer to QEMU#Host for a detailed guide on how to configure pulseaudio within QEMU.

AlsaMixer.app

Make alsamixer.app^AUR 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

Note: It can use only those output sinks that set as default.

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

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'.

Music Player Daemon (MPD)

configure MPD to use PulseAudio. See also MPD/Tips and Tricks#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.

Tips and tricks

Keyboard volume control

Map the following commands to your volume keys: XF86AudioRaiseVolume, XF86AudioLowerVolume, XF86AudioMute

First find out which sink corresponds to the audio output you'd like to control. To list available sinks:

pactl list sinks short

Suppose sink 0 is to be used, to raise the volume:

sh -c "pactl set-sink-mute 0 false ; pactl set-sink-volume 0 +5%"

To lower the volume:

sh -c "pactl set-sink-mute 0 false ; pactl set-sink-volume 0 -5%"

To mute/unmute the volume:

pactl set-sink-mute 0 toggle

To mute/unmute the microphone:

pactl set-source-mute 1 toggle

Tip: To have keyboard shortcuts operate always on the default sink, specify @DEFAULT_SINK@ as the sink number, for example pactl set-sink-mute @DEFAULT_SINK@ toggle.

Play sound from a non-interactive shell (systemd service, cron)

Set XDG_RUNTIME_DIR before the command (replace user_id with the ID of the user running PulseAudio):

XDG_RUNTIME_DIR=/run/user/user_id paplay /usr/share/sounds/freedesktop/stereo/complete.oga

Or use machinectl:

# machinectl shell .host --uid=user_id /usr/bin/paplay /usr/share/sounds/freedesktop/stereo/complete.oga

X11 Bell Events

To get pulseaudio to handle X11 bell events, run the following commands after the X11 session has been started:

pactl upload-sample /usr/share/sounds/freedesktop/stereo/bell.oga x11-bell
pactl load-module module-x11-bell sample=x11-bell display=$DISPLAY

To adjust the volume of the X11 bell, run the following command:

xset b 100

100 is a percentage. This requires the xorg-xset package. See Autostarting for a way to run these commands automatically when the X11 session is started.

Switch on connect

This is a module used to switch the output sound to the newly connected device. For example, if you plug in a USB headset, the output will be switched to that. If you unplug it, the output will be set back to the last device. This used to be quite buggy but got a lot of attention in PulseAudio 8.0 and should work quite well now.

If you just want to test the module then you can load it at runtime by calling:

# pactl load-module module-switch-on-connect

If you want to make the change persistent you will have to add it to your local pulseaudio settings or to /etc/pulse/default.pa (system wide effect). In either case, add this line:

load-module module-switch-on-connect

The factual accuracy of this article or section is disputed.

Reason: Editing /usr/bin/start-pulseaudio-x11 will not survive package upgrade. The offending module can be unloaded in the config before loading module-switch-on-connect, see Talk:Bluetooth_headset#GDMs_pulseaudio_instance_captures_bluetooth_headset. (Discuss in Talk:PulseAudio#)

On KDE/Plasma5 you should furthermore disable module-device-manager. As soon as Plasma5 is started it loads (via start-pulseaudio-x11) the module module-device-manager for pulseaudio to manage the devices. But that module apparently conflicts with module-switch-on-connect. Therefore you should disable that module by editing /bin/start-pulseaudio-x11 and commenting the lines for KDE. Simply logout and login again and in order to renew your pulseaudio session. On connect switching should now work properly.

Script for switching analogic outputs

Some sound cards present the option of multiple analog outputs, being switchable through using Pulseaudio profiles. But switching manually can become a chore, so you can use the following commands to switch it:

pactl set-sink-port 'number of the card' 'port'

This will set the default output to whatever port you chose. Example:

pactl set-sink-port 0 "analog-output;output-speaker"

The values can be easily obtained using:

pactl list

Current output can be obtained through:

pactl list sinks | grep "active profile"| cut -d ' ' -f 3-

This process can be automated through a simple script. This script then can be given a shortcut by the user:

~/pa.sh (or anything the user wants)

 #!/bin/bash
 # This script uses kdialog notification to warn the user of the currently swapped to profile. User could adapt it to their needs or change it.

 CURRENT_PROFILE=$(pactl list sinks | grep "active profile"| cut -d ' ' -f 3-)

 if [ "$CURRENT_PROFILE" = "analog-output;output-speaker" ] ; then
         pactl set-sink-port 0 "analog-output;output-headphones-1"
         kdialog --title "Pulseaudio" --passivepopup "Headphone" 2 & 
 else 
         pactl set-sink-port 0 "analog-output;output-speaker"      
         kdialog --title "Pulseaudio" --passivepopup  "Speaker" 2 &
 fi

 #Instructions
 #This script is intended to swap between two profiles. First checking the current profile then swapping it.
 #Users are required to change the field 'active profile' according to the language pactl reports.
 #Users might need to change the number of the card and the output to fit their machine.

Troubleshooting

See PulseAudio/Troubleshooting.