PulseAudio

Prerequisites[edit | edit source]

PulseAudio can use but does not need any of:

• sys-apps/systemd or
• sys-auth/elogind (remember to add elogind -systemd to global USE flag).

Kernel[edit | edit source]

For motherboards containing Intel HDA sound cards, use the following kernel option for improved power-saving:

Device Drivers  --->
    <*> Sound card support  --->
        <*> Advanced Linux Sound Architecture  --->
            (2048) Pre-allocated buffer size for HD-audio driver

CONFIG_HIGH_RES_TIMERS is needed to avoid (snd_pcm_recover) underrun errors and degraded audio when some applications are using pulseaudio:

General setup  --->
    Timers subsystem  --->
        [*] High Resolution Timer Support

USE flags[edit | edit source]

USE="pulseaudio"

Emerge[edit | edit source]

After setting USE flags be sure to update the system so the changes take effect:

Additional software[edit | edit source]

• media-sound/pavucontrol - Pulseaudio Volume Control, a GTK based mixer for PulseAudio.
• media-sound/pulsemixer - CLI and curses mixer for PulseAudio
• media-sound/paprefs - PulseAudio Preferences, a configuration dialogue for PulseAudio.
• KDE's Phonon integrated PulseAudio configuration and mixing, but it is not as powerful as pavucontrol or paprefs.
• media-sound/pulseaudio-modules-bt - replacement for bluetooth USE-flag, may have better sound quality and allows for a codec selection in pavucontrol

Permissions[edit | edit source]

PulseAudio uses udev to dynamically give access to the soundcards to the currently "active" user.

To make this possible, ACLs (Access Control Lists) are required:

File systems  --->
   Pseudo filesystems  --->
      [*] Tmpfs virtual memory file system support (former shm fs)
      [*]    Tmpfs POSIX Access Control Lists

If a desktop profile is not being used, check that sys-apps/systemd are installed with the acl USE flag enabled, and (if using OpenRC) that sys-auth/pambase is installed.

When finished, verify the permissions are working correctly:

<YOUR_USERNAME>

Configuring other applications[edit | edit source]

Some applications need to be configured to output to PulseAudio by default. A detailed list of these can be found on the PulseAudio wiki's PerfectSetup page.

ALSA

The media-plugins/alsa-plugins must be installed with the pulseaudio USE flag enabled:

OSS

You need to enable the following module in /etc/pulse/default.pa:

load-module module-oss

GStreamer

Several GConf keys must be set:

• Manual with gconftool:

ESD

Enable the following module in /etc/pulse/default.pa:

load-module module-protocol-esound-unix

Also eselect the PulseAudio implementation:

libao

Set the following in /etc/libao.conf:

default_driver=pulse

OpenAL

Set the following in /etc/openal/alsoft.conf:

drivers = pulse

MPlayer

Set the following in /etc/mplayer/mplayer.conf:

ao=pulse

Without udev or systemd[edit | edit source]

If you are using ALSA as a PulseAudio sink (output) and routing ALSA apps to PA but not using udev, you must set a specific device to be used. Otherwise, PulseAudio will use the ALSA device "default" as the sink, which may be routed back to PulseAudio, forming a loop. To avoid this, add the parameter device=hw:0,0 (you can find the correct IDs by running aplay -l). In the following example, we use two soundcards, of which card 0, device 0 is used as a sink (audio output, e.g. speakers) and card 1, device 0 as a source (audio input, e.g. microphone). PulseAudio will still be able to access other cards than these but it needs these settings to avoid looping the default device in this setup.

load-module module-alsa-sink device=hw:0,0
load-module module-alsa-source device=hw:1,0

Headless server[edit | edit source]

These instructions are for setting up a headless pulse audio server. Meaning a server which has no display on it but does have speakers. This provides the ability to use the remote server's speakers for audio output.

You will get warned in a dozen places for doing this, but it is the proper method.

load-module module-native-protocol-tcp auth-ip-acl=1.2.3.0/24
load-module module-alsa-sink

server (1.2.3.4) is the IP of the server.

load-module module-tunnel-sink server=1.2.3.4

Allow multiple users to use PulseAudio concurrently[edit | edit source]

In some situations, like software isolation, it may be desirable to run some programs as another users and have access to the Pulseaudio daemon. By default, the PulseAudio daemon does not accept connections by secondary users.

The following configuration runs PulseAudio daemon using a UNIX socket that accepts connections from other users.

load-module module-native-protocol-unix auth-anonymous=1 socket=/tmp/pulse-socket

default-server = unix:/tmp/pulse-socket

The above configuration allows different users to access the same sound server. Users do not need to be in the audio, pulse-access or pulse groups. PulseAudio server may need to be executed at startup with the command pulseaudio -D. For example, in case you are using i3wm:

exec pulseaudio -D

Equalizer[edit | edit source]

Make sure you installed pulseaudio with the equalizer USE flag enabled.

load-module module-dbus-protocol
load-module module-equalizer-sink

No sound[edit | edit source]

• After installation: If you have no sound while using ALSA, consider unmuting the sound card. Launch alsamixer and make sure each column has a green 00 under it (use the m key to toggle mute/unmute). Install media-sound/pavucontrol and check if there is any output on the pavucontrol panel when playing audio.
• After upgrading the system: pulseaudio's user configuration files can become corrupt. Deleting ~/.pulse* configuration files and forcing fresh ones to be generated by restarting the daemon may fix no sound condition.

Enable debug mode[edit | edit source]

To get more informations you need to set the following in /etc/pulse/daemon.conf:

log-level=debug

Afterward restart the daemon:

Audio/Video out of sync[edit | edit source]

When using PulseAudio over your local network, you can experience out-of-sync problems. Solve this by adding tsched=0:

load-module module-udev-detect tsched=0

This disables time scheduling. Afterwards restart the daemon:

Dummy output[edit | edit source]

If the only playback device is the Dummy Output, PulseAudio cannot access your sound devices. Either the user has no permissions (see section Permissions or another program blocks the access. Try:

It shows the relevant program. Close the program and reconfigure it to use PulseAudio.

No guarantees on actual latencies[edit | edit source]

Currently PA provides whatever latency at that moment is possible be it some milliseconds to hundreds of milliseconds without regard to what applications ask for.

In case of buffer under-run latencies are never decreased[edit | edit source]

Currently, if a buffer under-run occurs, PA buffers for longer increasing latency, but it then never tries to buffer for less until restart.

Re-sampling using up a lot of CPU time[edit | edit source]

Re-sampling can require quite a lot of computational power, PA defaults are rather conservative but in certain cases can still take a significant toll, in such cases edit /etc/pulse/daemon.conf and consider changing resample-method to something less CPU intensive, default-sample-format and default-sample-rate can also affect CPU utilization with higher bit-depth and larger difference in sample-rate generally needing more resources (e.g. re-sampling 44.1 kHz to 48 kHz is faster than re-sampling either to 192 kHz). Since re-sampling is done per each channel per input, channel configuration and number of applications can affect performance as well.

Starting with version 7.0 there is also soxr resamplers made available by enabling the sox USE flag. In particular resample-method = soxr-mq should provide acceptable quality while even the higher quality and hence slower soxr-hq is still cheaper than the default speex-float-1. But be warned that the soxr resamplers have roughly 5-20 times higher latency than speex-float, in terms of time the worst case for soxr-mq/hq can be as high as 20 ms while soxr-vhq latency can in few specific setups reach over 27 ms. In terms of feeling 20 ms can range from unnoticeable to irritating depending on person and use case (the usual PA latency's lower bound is around 20-25 ms and more commonly often around 70-90 ms, for comparison).

grsec and PulseAudio[edit | edit source]

Make sure CONFIG_GRKERNSEC_SYSFS_RESTRICT is not enabled if you are using a grsecurity kernel. PulseAudio’s module-udev-detect needs to access /sys to discover what cards are available on the system, and that kernel option disallows this for anyone but root.

Volume gets randomly louder or reset to 100%[edit | edit source]

This may be caused by misbehaving PulseAudio-enabled programs when PulseAudio has flat volumes feature enabled. Disable it in daemon config:

flat-volumes = no

In pavucontrol, unable to change output device for applications that use OpenALsoft[edit | edit source]

source

It can happen that you want to change the output device for an application, but trying to change it in pavucontrol has no effect. If this application use OpenALsoft, this one has a configuration option that inhibits sink changes. To disable this option, you can create a configuration file for OpenALsoft :

[pulse]
allow-moves=yes

Or, by running alsoft-config :