Pipewire

Overview ​

A low-level multimedia framework.

Restart pipewire components with:

systemctl --user restart wireplumber pipewire pipewire-pulse

Sample rate ​

Allowing both 44.1kHz and 48kHz may help fixing some cracklings.

cp /usr/share/pipewire/pipewire.conf ~/.config/pipewire/pipewire.conf

Add to ~/.config/pipewire/pipewire.conf > context.modules:

default.clock.allowed-rates = [ 44100 48000 ]

Nice level ​

For the time I'm writing this (2022/11/27), the default client-rt.conf does not contain a default nice.level, which makes applications that use pipewire directly (not through pipewire-pulse) have a lower priority. mpv, for example, was having some audio cracklings.

cp /usr/share/pipewire/client-rt.conf ~/.config/pipewire/client-rt.conf

Add to ~/.config/pipewire/client-rt.conf > context.modules > libpipewire-module-rt:

args = {
    nice.level    = -11
}

Sink/source management ​

List ​

List sources/sinks:

pactl list short sources
pactl list short sinks
wpctl status

Default Sink ​

Copy the base pipewire-pulse configuration:

cp /usr/share/pipewire/pipewire-pulse.conf ~/.config/pipewire/pipewire-pulse.conf

Then append the following to context.exec:

context.exec = [
    { path = "/usr/bin/sh" args = "/path/to/pipewire-init.sh" }
]

Create the pipewire-init.sh with the command that sets the default sink (and optionally add more initialization commands).

##!/usr/bin/sh
sleep 0.5
pactl set-default-sink alsa_output.pci-0000_2f_00.4.analog-stereo

Using pipewire (untested) ​

• Reference

Add the following to pipewire.conf:

context.properties = {
    default.configured.audio.sink = { "name": "your_device_name" }
}

Virtual Sink ​

• Remap Sink Wiki
• Loopback Module Documentation

Create a sink that can be selected in applications and that forwards the data to another sink. Useful, for example, if you want to record audio from only one application.

To create the sink temporarily, run either:

pactl load-module module-remap-sink sink_name=recording
pw-loopback --name='Recording' --capture-props='media.class=Audio/Sink node.name=recording'

To create the sink permanently, create ~/.config/pipewire/pipewire-pulse.conf.d/10-remap-sink.conf and restart pipewire.

context.modules = [
    {   name = libpipewire-module-loopback
        args = {
            node.description = "Audio/Sink Recording"
            capture.props = {
                media.class      = "Audio/Sink"
                node.name        = recording
                audio.position   = [FL FR]
            }
            playback.props = {
                audio.position   = [FL FR]
            }
        }
    }
]

Combine sources ​

• Migrate PA: module-null-sink
• Virtual Devices Configuration

1) Create a null sink ​

To create the sink temporarily:

pactl load-module module-null-sink sink_name=mix
pw-cli create-node adapter factory.name=support.null-audio-sink media.class="Audio/Sink" object.linger=1 monitor.channel-volumes=1 node.name=mix

To create the sink permanently, create ~/.config/pipewire/pipewire.conf.d/10-null-sink.conf and restart pipewire.

context.objects = [
    {   factory = adapter
        args = {
            factory.name            = support.null-audio-sink
            media.class             = "Audio/Sink"
            node.name               = mix
            node.description        = "NullSink Mix"
            object.linger           = 1
            monitor.channel-volumes = 1
        }
    }
]

2) Connect sources to the null sink ​

pactl load-module module-loopback sink=mix source=${speakers}
pactl load-module module-loopback sink=mix channels=2 channel_map=mono,mono source=${mic}
pw-loopback --capture=${speakers} --capture-props='stream.capture.sink=true' --playback=mix
pw-loopback --capture=${mic} --capture-props='audio.position=[FL] stream.dont-remix=true' --playback=mix --playback-props='audio.position=[MONO]'

The mix sink with have the audio of both sources.

Note: PIPEWIRE_NODE environment variable seems to affect the module-loopback in a way that makes it not work.