PipeWire

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Revision as of 18:32, 23 March 2021 by Govynnus (talk | contribs) (Update for new pipewire configuration format)
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This material is work-in-progress ...

The instructions below have not been thoroughly tested and may break things.
(Last edited by Govynnus on 23 Mar 2021.)

PipeWire is a multimedia processing engine that aims to improve audio and video handling on Linux.

Prerequisites

Audio Group

Add your normal user to the audio group. The user must log in for this to take effect.

# addgroup audio <user>

D-Bus

PipeWire requires a running D-Bus session. If you use a full desktop environment this will probably be started automatically, but with minimal window managers it must be done manually.

# apk add dbus dbus-openrc dbus-x11
# rc-service dbus start
# rc-update add dbus default

Then use dbus-launch whenever you start an X or Wayland session. For example:

$ dbus-launch --exit-with-session sway

Installation and configuration

# apk add pipewire

Uncomment the following line in /etc/pipewire/pipewire.conf:

{ path = "/usr/bin/pipewire-media-session"  args = "" }

Enable the snd_seq kernel module for ALSA support.

# modprobe snd_seq
# echo snd_seq >> /etc/modules

PulseAudio

PipeWire can run a PulseAudio daemon which should allow all existing PulseAudio applications to be used with the PipeWire backend.

# apk add pipewire-pulse

To enable the PulseAudio daemon edit /etc/pipewire/pipewire.conf and uncomment the following line:

{ path = "/usr/bin/pipewire" args = "-c pipewire-pulse.conf" }

JACK

If you will be using PipeWire for JACK applications install the required package and make system wide links to the PipeWire replacement JACK libraries (I have not had success using pw-jack). You will not need to start a JACK server.

# apk add pipewire-jack
# ln -sf /usr/lib/pipewire-0.3/jack/libjackserver.so.0 /usr/lib/libjackserver.so.0
# ln -sf /usr/lib/pipewire-0.3/jack/libjacknet.so.0 /usr/lib/libjacknet.so.0
# ln -sf /usr/lib/pipewire-0.3/jack/libjack.so.0 /usr/lib/libjack.so.0
Note: These symlinks might be overwritten during updates.

Video

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

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 and on KDE Plasma with xdg-desktop-portal-kde and Firefox.

Usage

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

$ pipewire

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!

$ pw-cat -p --list-targets

Test sound is working using an audio file in a format supported by libsndfile (e.g. flac, opus, ogg, wav).

$ pw-cat -p test.flac

If you have a microphone test recording audio 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

Test PulseAudio clients using a media player (most use PulseAudio) and if you use JACK test that too:

# apk add jack-example-clients
$ jack_simple_client

You should hear a sustained beep.

If you are happy everything is working, make PipeWire start automatically when your X or Wayland session starts. For example, you could add the pipewire command to ~/.xinitrc or your window manager's config file.

See Also