Well-known features — WirePlumber 0.5.17 documentation

# Well-known features

This is a list of some well-known features that can be enabled or disabled accordingly.

There are many more features actually defined in the configuration file, and it can be confusing to go through them. This list here is meant to be a quick reference for the most common ones that actually make sense to be toggled in a configuration file in order to customize WirePlumber's behavior.

For more information on what features are and how they work, refer to the previous section: Components & Profiles.

## Hardware monitors

### Audio

hardware.audio

  Enables bringing up audio hardware.

  Wants:

    `monitor.alsa`, `monitor.alsa-midi`

monitor.alsa

  Enables the ALSA device monitor.

  Wants:

    `monitor.alsa.reserve-device`

monitor.alsa.reserve-device

  Enables D-Bus device reservation API for ALSA devices.

  Requires:

    `support.reserve-device`

monitor.alsa-midi

  Enables the ALSA MIDI device monitor.

node.software-dsp

  Enables software DSP based on pre-configured hardware rules, by hiding the hardware node and exposing a separate virtual node in its place. New configurations should use `hooks.filter.graph` instead.

  See Automatic Software DSP for more information.

### Bluetooth

hardware.bluetooth

  Enables bringing up bluetooth hardware.

  Wants:

    `monitor.bluez`, `monitor.bluez-midi`

monitor.bluez

  Enables the BlueZ device monitor.

  Wants:

    `monitor.bluez.seat-monitoring`

monitor.bluez.seat-monitoring

  Enables seat monitoring on the bluetooth monitor.

  When enabled, this will make sure that the bluetooth devices are only enabled on the active seat.

  Requires:

    `support.logind`

monitor.bluez-midi

  Enables the BlueZ MIDI device monitor.

  Wants:

    `monitor.bluez.seat-monitoring`

### Video

hardware.video-capture

  Enables bringing up video capture hardware (cameras, hdmi capture devices, etc.)

  Wants:

    `monitor.v4l2`, `monitor.libcamera`

monitor.v4l2

  Enables the V4L2 device monitor.

monitor.libcamera

  Enables the libcamera device monitor.

## Support components

support.client-context

  Starts a secondary `pw_context`, running on its own thread, which hosts every PipeWire object that WirePlumber implements in its own process: the PipeWire modules loaded as `pw-module-client` components or from Lua with `LocalModule()`, the nodes created with `LocalNode()` and the SPA device handles wrapped by `SpaDevice()`.

  WirePlumber's main loop also dispatches the event dispatcher, whose hooks can run for a long time, and GSource priorities do not preempt: anything sharing that loop makes no progress for as long as a hook runs. In-process media objects (i.e. local nodes and modules) should be given their own loop to be able to receive media commands without delays, or they may lose audio.

  This is enabled by default and there is rarely a reason to disable it. If it is disabled, those objects fall back to WirePlumber's main `pw_context` and become subject to the delays described above.

support.dbus

  Provides a D-Bus connection to the session bus. This is needed by some other support features (see below) but it is generally optional. WirePlumber does not require a D-Bus connection to work.

  On a system where WirePlumber is configured to run system-wide (headless, embedded, etc), this will most likely fail to load and thus disable all the other support features that require it. On such systems it makes sense to disable this feature explicitly, to avoid the overhead of trying to connect to the session bus.

support.reserve-device

  Provides support for the D-Bus device reservation API, allowing the device monitors to reserve devices for exclusive access.

  Requires:

    `support.dbus`

support.portal-permissionstore

  Integrates with the flatpak portal permission store to give appropriate access permissions to flatpak applications.

  Requires:

    `support.dbus`

support.logind

  Integrates with systemd-logind to enable specific functionality only on the active seat.

support.modem-manager

  Integrates with ModemManager to track the state of voice calls, so that a "Voice Call" device profile can be selected while a call is in progress.

  Requires:

    `support.system-dbus`

support.mpris

  Provides MPRIS media player control. This is what allows WirePlumber to pause media players when the sink they are playing to disappears; see the `linking.pause-playback` setting in Well-known settings.

  Requires:

    `support.dbus`

support.session-services

  Announces which session management services this WirePlumber instance actually provides, by setting the `session.services` property on its PipeWire client object. This is how other software can tell what a given instance is responsible for, which matters in a multi-instance setup.

api.notifications

  Provides an API for sending desktop notifications through `org.freedesktop.Notifications`. It is used, for instance, to notify the user when devices are auto-muted.

  Requires:

    `support.dbus`

metadata.sm-objects

  Creates the `sm-objects` metadata, through which clients can ask WirePlumber to load and unload objects — PipeWire modules, session items and so on — at runtime.

## Nodes

node.audio-group

  Groups together the streams of processes that share a common ancestor, placing them behind a single loopback filter so that they can be controlled as one.

hooks.filter.graph

  Enables attaching an internal filter graph to a node, based on the `node.filter-graph.rules` configuration section, without exposing extra nodes in the graph. This is the preferred way to apply software DSP to a node; see Internal filter graphs.

  The `filter-graph.conf` example fragment demonstrates this; see Example configuration fragments.

## Policies

policy.standard

  Enables the standard WirePlumber policy. This includes all the logic for enabling devices, linking streams, granting permissions to clients, etc, as appropriate for a desktop system.

policy.linking.role-based

  Enables the role based priority system policy. This system creates virtual sinks that group streams based on their `media.role` property, and assigns a priority to each role. Depending on the priority configuration, lower priority roles may be corked or ducked when a higher priority role stream is active.

  This policy was designed for automotive and mobile systems and may not work as expected on desktop systems.

  Note that this policy is implemented as a superset of `policy.standard`, so `policy.standard` should not be disabled when enabling this policy.

  Requires:

    `policy.standard`