Difference between revisions of "PulseAudio"

Latest revision as of 08:32, 11 August 2017

PulseAudio 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.

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

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

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.

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.

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.

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.

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.

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

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

/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:

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

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

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

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 [3].

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. See Extra keyboard keys in Xorg for details.

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

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

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

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.

See also

• .asoundrc on ALSA wiki
• PulseAudio official site
• PulseAudio FAQ