PipeWire: Difference between revisions

Latest revision as of 05:26, 29 September 2024

PipeWire is a multimedia processing engine that aims to improve audio and video handling on Linux. Pipewire can act as a replacement for both PulseAudio and ALSA servers.

Prerequisites

Device access

PipeWire needs proper permissions to access devices. If you do not use elogind, your user should be in audio (to access audio devices) and video (to access webcam devices) groups:

# addgroup <user> audio # addgroup <user> video

Warning: Membership of the video group will also grant unrestricted access to video devices, which is often a security issue. See issue #15409 for further details.

See pre-systemd groups for more info. Make sure to re-login for these changes to take effect.

D-Bus

PipeWire requires a running D-Bus system and/or session bus for most of its functionality. If you start session-wide dbus instance, make sure to start PipeWire in that same session.

Environment

Ensure that XDG_RUNTIME_DIR is configured correctly. If this is not set, pipewire will create a directory in your home folder instead, called ~/pulse, and on attempting to run Pavucontrol or pactl, you will get the following error:

$ pactl list
Connection failure: Connection refused
pa_context_connect() failed: Connection refused

Under Sway, in order for xdg-desktop-portal-wlr to work it may also be necessary to set XDG_CURRENT_DESKTOP and XDG_SESSION_DESKTOP to sway

Installation

Install the following pipewire, wireplumber a session manager and pipewire-pulse, so Pulseaudio applications could use PipeWire as backend. By doing this, PipeWire acts as an audio server, similar to PulseAudio server.

# apk add pipewire

# apk add wireplumber

# apk add pipewire-pulse

pipewire-pulse package by itself will install the above pipewire package and wireplumber automatically.

JACK compatibility

Since Pipewire aims to replace JACK Install pipewire-jack package, so it provides ABI-compatible libraries for JACK applications.

# apk add pipewire-jack

ALSA support

Install pipewire-alsa package.

# apk add pipewire-alsa

GUI Tools

You might want to use pavucontrol or pavucontrol-qt to have a simple GUI app for controlling sound, outputs, etc.

qpwgraph is a graph manager dedicated to PipeWire with Qt GUI Interface.

Install XFCE Audio Mixer Plugin to help control volume:

doas apk add gst-plugin-pipewire

Configuration

PipeWire and WirePlumber store their default configuration in /usr/share/pipewire and /usr/share/wireplumber respectively. If you want to edit the configuration, you need to move it to /etc:

# cp -a /usr/share/pipewire /etc # cp -a /usr/share/wireplumber /etc

pipewire-launcher

Tip: You can also use superd to manage pipewire and its related services.

Note: pipewire-launcher script is provided by Alpine Linux, not by upstream. Please report issues to Alpine Linux maintainers first.

Start the PipeWire media server. You'll probably get quite a few errors but just ignore them for now.

$ /usr/libexec/pipewire-launcher

A D-Bus session service must be running unless dbus support is disabled.

If .xinitrc is used, add /usr/libexec/pipewire-launcher to your ~/.xinitrc.

If you do not use GUI by default and have D-Bus enabled in configuration, add the following stanza to your shell configuration file:

export $(dbus-launch) /usr/libexec/pipewire-launcher

Screen sharing on Wayland

You will need the right xdg-desktop-portal backend for your desktop environment. Screen sharing is known to work on:

GNOME with xdg-desktop-portal-gtk
KDE Plasma with xdg-desktop-portal-kde and Firefox
Sway with xdg-desktop-portal-wlr and Firefox, see Sway for details

Bluetooth audio

Enable PulseAudio support as described above
Install bluetooth service packages: bluez bluez-openrc pipewire-spa-bluez
Optional: install GUI manager for bluetooth blueman
Enable and start bluetooth service: rc-update add bluetooth; rc-service bluetooth start
Restart PipeWire
Use commandline program bluetoothctl or GUI program blueman-manager to scan and pair bluetooth audio devices.
Use pavucontrol to adjust volume and manually select high definition bluetooth codecs.

Video

Video should work out-of-the-box with v4l2 devices (e.g. a lot of webcams) and GStreamer applications.

Realtime scheduling

For realtime scheduling, it is recommended to use rtkit. Add your user to the rtkit group.

Alternatively, ensure your user has the right ulimit permissions. Since pipewire 0.3.66, you can add yourself to the pipewire group. You generally need (e.g. in /etc/security/limits.conf):

@pipewire - memlock 4194304
@pipewire - nice -19
@pipewire - rtprio 95

This allows a member of the pipewire group to have the right permissions for PipeWire to use realtime scheduling without rtkit. This same snippet comes with pipewire since 0.3.66, so if you have a PAM login session and add yourself to the pipewire group, you don't have to do anything else.

Note that the above limits.conf will only work if your session is using PAM.

Disable D-Bus support

Warning: This section is no longer supported since Alpine 3.19 as Using lua for configuration files is no longer supported in version 0.5.

For certain configurations (e.g. only audio playback and recording) D-Bus setup is not necessary and it can be disabled as follows.

Edit the following configuration parameters:

Contents of /etc/pipewire/pipewire.conf

context.properties = {
    ... 
    support.dbus = false
}

Contents of /etc/wireplumber/wireplumber.conf

context.properties = {
    ... 
    support.dbus = false
}

Contents of /etc/wireplumber/bluetooth.lua.d/50-bluez-config.lua

bluez_monitor.properties = {
  ...
  ["with-logind"] = false,
}

Contents of /etc/wireplumber/main.lua.d/50-alsa-config.lua

alsa_monitor.properties = {
  ...
  ["alsa.reserve"] = false,
}

Contents of /etc/wireplumber/main.lua.d/50-default-access-config.lua

default_access.properties = {
  ...
  ["enable-flatpak-portal"] = false,
}

Testing

In a different terminal window check the default output device. I don't yet know how this default can be changed for all applications, so you'd better hope it's right!

WirePlumber

$ wpctl status

pw-cat playback

Test sound is working using an audio file in a format supported by libsndfile 🔓 (e.g. flac, opus, ogg, wav). Use pw-cat utility from pipewire-tools:

$ pw-cat -p test.flac $ pw-play /usr/share/sounds/alsa/Front_Center.wav

pw-cat recording

If you have a microphone test audio recording is working.

$ pw-cat -r --list-targets $ pw-cat -r recording.flac (Speak for a while then stop it with Ctrl+c) $ pw-cat -p recording.flac

PulseAudio

Test PulseAudio clients using a media player, as most use PulseAudio.

JACK

Use jack_simple_client from jack-simple-clients:

$ jack_simple_client

You should hear a sustained beep.

Troubleshooting

`wpctl status` shows no targets

First, check whether ALSA knows about your sound card:

aplay -l

If sound devices are found, the issue is with your pipewire configuration. Consider double-checking the instructions above.

Otherwise, your sound card may not be supported in the version of the Linux Kernel you're running. You should search online for fixes relating to your current kernel version and the codec of your sound card. You can find each of these with:

uname -r cat /proc/asound/card0/codec*

Modern devices might require sof-firmware, which is the case if you get sof firmware file is missing errors in dmesg.

Error acquiring bus address: Cannot autolaunch D-Bus without X11 $DISPLAY

This means D-Bus session bus is not started and GUI is not active (i.e. you are in a tty). Use dbus-run-session as outlined above. Alternatively, disable D-Bus support.

Bluetooth connect failed: br-connection-profile-unavailable

Ensure that Session Manager is running.

Play/Pause buttons not working on bluetooth headphones

Check /var/log/messages. If you see something like this:

bluetoothd[3463]: profiles/audio/avctp.c:uinput_create() Can't open input device: No such file or directory (2)
bluetoothd[3463]: profiles/audio/avctp.c:init_uinput() AVRCP: failed to init uinput for WH-1000XM5

Then bluez is trying to register the headphones buttons as an input devices, but uinput is not loaded. Try modprobe uinput. If this works, see Architecture#Module_Loading for instructions on how to make sure this module is loaded automatically on each startup.