pipewire.conf

Table of Contents

• DROP-IN CONFIGURATION FILES
• CONFIGURATION FILE FORMAT
• CONFIGURATION FILE SECTIONS
• CONTEXT PROPERTIES
• SPA LIBRARIES
• MODULES
• CONTEXT OBJECTS
• COMMAND EXECUTION
• MATCH RULES
• CONTEXT PROPERTIES RULES
• NODE RULES
• DEVICE RULES

The PipeWire server configuration file

SYNOPSIS

$XDG_CONFIG_HOME/pipewire/pipewire.conf

/etc/pipewire/pipewire.conf

/usr/share/pipewire/pipewire.conf

/usr/share/pipewire/pipewire.conf.d/

/etc/pipewire/pipewire.conf.d/

$XDG_CONFIG_HOME/pipewire/pipewire.conf.d/

DESCRIPTION

PipeWire is a service that facilitates sharing of multimedia content between devices and applications.

On startup, the daemon reads a main configuration file to configure itself. It executes a series of commands listed in the config file.

The config file is looked up in the order listed in the SYNOPSIS. The environment variables PIPEWIRE_CONFIG_DIR, PIPEWIRE_CONFIG_PREFIX and PIPEWIRE_CONFIG_NAME can be used to specify an alternative config directory, subdirectory and file respectively.

Other PipeWire configuration files generally follow the same lookup logic, replacing pipewire.conf with the name of the particular config file.

DROP-IN CONFIGURATION FILES

All *.conf files in the pipewire.conf.d/ directories are loaded and merged into the configuration. Dictionary sections are merged, overriding properties if they already existed, and array sections are appended to. The drop-in files have same format as the main configuration file, but only contain the settings to be modified.

As the pipewire.conf configuration file contains various parts that must be present for correct functioning, using drop-in files for configuration is recommended.

Example

A configuration file ~/.config/pipewire/pipewire.conf.d/custom.conf to change the value of the default.clock.min-quantum setting in pipewire.conf:

context.properties = {
    default.clock.min-quantum = 128
}

CONFIGURATION FILE FORMAT

The configuration file is in "SPA" JSON format.

The configuration file contains top-level keys, which are the sections. The value of a section is either a dictionary, { }, or an array, [ ]. Section and dictionary item declarations have KEY = VALUE form, and are separated by whitespace. For example:

context.properties = {  # top-level dictionary section
 
    key1 = value  # a simple value
 
    key2 = { key1 = value1 key2 = value2 }  # a dictionary with two entries
 
    key3 = [ value1 value2 ]  # an array with two entries
 
    key4 = [ { k = v1 } { k = v2 } ]  # an array of dictionaries
 
}
 
context.modules = [  # top-level array section
 
    value1
 
    value2
 
]

The configuration files can also be written in standard JSON syntax, but for easier manual editing, the relaxed "SPA" variant is allowed. In "SPA" JSON:

• : to delimit keys and values can be substituted by = or a space.
• " around keys and string can be omitted as long as no special characters are used in the strings.
• , to separate objects can be replaced with a whitespace character.
• # can be used to start a comment until the line end

CONFIGURATION FILE SECTIONS

context.properties

Dictionary. These properties configure the PipeWire instance.

context.spa-libs

Dictionary. Maps plugin features with globs to a spa library.

context.modules

Array of dictionaries. Each entry in the array is a dictionary with the name of the module to load, including optional args and flags. Most modules support being loaded multiple times.

context.objects

Array of dictionaries. Each entry in the array is a dictionary containing the factory to create an object from and optional extra arguments specific to that factory.

context.exec

Array of dictionaries. Each entry in the array is dictionary containing the path of a program to execute on startup and optional args.

This array used to contain an entry to start the session manager but this mode of operation has since been demoted to development aid. Avoid starting a session manager in this way in production environment.

node.rules

Array of dictionaries. Match rules for modifying node properties on the server.

device.rules

Array of dictionaries. Match rules for modifying device properties on the server.

CONTEXT PROPERTIES

Available PipeWire properties in context.properties and possible default values.

clock.power-of-two-quantum = true

The quantum requests from the clients and the final graph quantum are rounded down to a power of two. A power of two quantum can be more efficient for many processing tasks.

context.data-loop.library.name.system

The name of the shared library to use for the system functions for the data processing thread. This can typically be changed if the data thread is running on a realtime kernel such as EVL.

loop.rt-prio = -1

The priority of the data loops. The data loops are used to schedule the nodes in the graph. A value of -1 uses the default realtime priority from the module-rt. A value of 0 disables realtime scheduling for the data loops.

loop.class = [ data.rt .. ]

An array of classes of the data loops. Normally nodes are assigned to a loop by name or by class. Nodes are by default assigned to the data.rt class so it is good to have a data loop of this class as well.

context.num-data-loops = 1

The number of data loops to create. By default 1 data-loop is created and all nodes are scheduled in this thread. A value of 0 disables the real-time data loops and schedules all nodes in the main thread. A value of -1 spawns as many data threads as there are cpu cores.

context.data-loops = [ ... ]

This controls the data loops that will be created for the context. Is is an array of data loop specifications, one entry for each data loop to start:

context.data-loops = [
    {
         #library.name.system = support/libspa-support
         loop.rt-prio = -1
         loop.class = [ data.rt .. ]
         thread.name = data-loop.0
         thread.affinity = [ 0 1 ]
    }
    ...
]

A specific priority, classes and name can be given with loop.rt-prio, loop.class and thread.name respectively. It is also possible to pin the data loop to specific CPU cores with the thread.affinity property.

core.daemon = false

Makes the PipeWire process, started with this config, a daemon process. This means that it will manage and schedule a graph for clients. You would also want to configure a core.name to give it a well known name.

core.name = pipewire-0

The name of the PipeWire context. This will also be the name of the PipeWire socket clients can connect to.

cpu.zero.denormals = false

Configures the CPU to zero denormals automatically. This will be enabled for the data processing thread only, when enabled.

cpu.vm.name = null

This will be set automatically when the context is created and will contain the name of the VM. It is typically used to write match rules to set extra properties.

default.clock.rate = 48000

The default clock rate determines the real time duration of the min/max/default quantums. You might want to change the quantums when you change the default clock rate to maintain the same duration for the quantums.

default.clock.allowed-rates = [ ]

It is possible to specify up to 32 alternative sample rates. The graph sample rate will be switched when devices are idle. Note that this is not enabled by default for now because of various kernel and Bluetooth issues. Note that the min/max/default quantum values are scaled when the samplerate changes.

default.clock.min-quantum = 32

Default minimum quantum.

default.clock.max-quantum = 8192

Default maximum quantum.

default.clock.quantum = 1024

Default quantum used when no client specifies one.

default.clock.quantum-limit = 8192

Maximum quantum to reserve space for. This is the maximum buffer size used in the graph, regardless of the samplerate.

default.clock.quantum-floor = 4

Minimum quantum to reserve space for. This is the minimum buffer size used in the graph, regardless of the samplerate.

default.video.width

Default video width

default.video.height

Default video height

default.video.rate.num

Default video rate numerator

default.video.rate.denom

Default video rate denominator

library.name.system = support/libspa-support

The name of the shared library to use for the system functions for the main thread.

link.max-buffers = 64

The maximum number of buffers to negotiate between nodes. Note that version < 3 clients can only support 16 buffers. More buffers is almost always worse than less, latency and memory wise.

log.level = 2

The default log level used by the process.

mem.allow-mlock = true

Try to mlock the memory for the realtime processes. Locked memory will not be swapped out by the kernel and avoid hickups in the processing threads.

mem.warn-mlock = false

Warn about failures to lock memory.

mem.mlock-all = false

Try to mlock all current and future memory by the process.

settings.check-quantum = false

Check if the quantum in the settings metadata update is compatible with the configured limits.

settings.check-rate = false

Check if the rate in the settings metadata update is compatible with the configured limits.

support.dbus = true

Enable DBus support. This will enable DBus support in the various modules that require it. Disable this if you want to globally disable DBus support in the process.

vm.overrides = { default.clock.min-quantum = 1024 }

Any property in the vm.overrides property object will override the property in the context.properties when PipeWire detects it is running in a VM. This is deprecated, use the context.properties.rules instead.

context.modules.allow-empty = false

By default, a warning is logged when there are no context.modules loaded because this likely indicates there is a problem. Some applications might load the modules themselves and when they set this property to true, no warning will be logged.

The context properties may also contain custom values. For example, the context.modules and context.objects sections can declare additional conditions that control whether a module or object is loaded depending on what properties are present.

SPA LIBRARIES

SPA plugins are loaded based on their factory-name. This is a well known name that uniquely describes the features that the plugin should have. The context.spa-libs section provides a mapping between the factory-name and the plugin where the factory can be found.

Factory names can contain a wildcard to group several related factories into one plugin. The plugin is loaded from the first matching factory-name.

Example

context.spa-libs = {
    audio.convert.* = audioconvert/libspa-audioconvert
    avb.*           = avb/libspa-avb
    api.alsa.*      = alsa/libspa-alsa
    api.v4l2.*      = v4l2/libspa-v4l2
    api.libcamera.* = libcamera/libspa-libcamera
    api.bluez5.*    = bluez5/libspa-bluez5
    api.vulkan.*    = vulkan/libspa-vulkan
    api.jack.*      = jack/libspa-jack
    support.*       = support/libspa-support
    video.convert.* = videoconvert/libspa-videoconvert
}

MODULES

PipeWire modules to be loaded. See libpipewire-modules(7).

context.modules = [
    #{ name = MODULENAME
    #    ( args  = { KEY = VALUE ... } )
    #    ( flags = [ ( ifexists ) ( nofail ) ] )
    #    ( condition = [ { KEY = VALUE ... } ... ] )
    #}
    #
]

name

Name of module to be loaded

args = { }

Arguments passed to the module

flags = [ ]

Loading flags. ifexists to only load module if it exists, and nofail to not fail PipeWire startup if the module fails to load.

condition = [ ]

A match rule matches condition. The module is loaded only if one of the expressions in the array matches to a context property.

CONTEXT OBJECTS

The context.objects section allows you to make some objects from factories (usually created by loading modules in context.modules).

context.objects = [
    #{ factory = <factory-name>
    #    ( args  = { <key> = <value> ... } )
    #    ( flags = [ ( nofail ) ] )
    #    ( condition = [ { <key> = <value> ... } ... ] )
    #}
]

This section can be used to make nodes or links between nodes.

factory

Name of the factory to create the object.

args = { }

Arguments passed to the factory.

flags = [ ]

Flag nofail to not fail PipeWire startup if the object fails to load.

condition = [ ]

A match rule matches condition. The object is created only if one of the expressions in the array matches to a context property.

Example

This fragment creates a new dummy driver node, but only if core.daemon property is true:

context.objects = [
    { factory = spa-node-factory
      args = {
          factory.name    = support.node.driver
          node.name       = Dummy-Driver
          node.group      = pipewire.dummy
          priority.driver = 20000
      },
      condition = [ { core.daemon = true } ]
    }
]

COMMAND EXECUTION

The context.exec section can be used to start arbitrary commands as part of the initialization of the PipeWire program.

context.exec = [
    #{   path = <program-name>
    #    ( args = "<arguments>" | [ <arg1> <arg2> ... ] )
    #    ( condition = [ { <key> = <value> ... } ... ] )
    #}
]

path

Program to execute.

args

Arguments to the program.

condition

A match rule matches condition. The object is created only if one of the expressions in the array matches to a context property.

Example

The following fragment executes a pactl command with the given arguments:

context.exec = [
    { path = "pactl" args = "load-module module-always-sink" }
]

MATCH RULES

Some configuration file sections contain match rules. This makes it possible to perform some action when an object (usually a node or stream) is created/updated that matches certain properties.

The general rules object follows the following pattern:

<rules> = [
    {
        matches = [
            # any of the following sets of properties are matched, if
            # any matches, the actions are executed
            {
                # <key> = <value>
                # all keys must match the value. ! negates. ~ starts regex.
                #application.process.binary = "teams"
                #application.name = "~speech-dispatcher.*"
 
                # Absence of property can be tested by comparing to null
                #pipewire.sec.flatpak = null
            }
            {
                # more matches here...
            }
            ...
        ]
        actions = {
            <action-name> = <action value>
            ...
        }
    }
]

Match rules are an array of rules.

A rule is always a JSON object with two keys: matches and actions. The matches key is used to define the conditions that need to be met for the rule to be evaluated as true, and the actions key is used to define the actions that are performed when the rule is evaluated as true.

The matches key is always a JSON array of objects, where each object defines a condition that needs to be met. Each condition is a list of key-value pairs, where the key is the name of the property that is being matched, and the value is the value that the property needs to have. Within a condition, all the key-value pairs are combined with a logical AND, and all the conditions in the matches array are combined with a logical OR.

The actions key is always a JSON object, where each key-value pair defines an action that is performed when the rule is evaluated as true. The action name is specific to the rule and is defined by the rule’s documentation, but most frequently you will see the update-props action, which is used to update the properties of the matched object.

In the matches array, it is also possible to use regular expressions to match property values. For example, to match all nodes with a name that starts with my_, you can use the following condition:

matches = [
  {
    node.name = "~my_.*"
  }
]

The ~ character signifies that the value is a regular expression. The exact syntax of the regular expressions is the POSIX extended regex syntax, as described in the regex (7) man page.

In addition to regular expressions, you may also use the ! character to negate a condition. For example, to match all nodes with a name that does not start with my_, you can use the following condition:

matches = [
  {
    node.name = "!~my_.*"
  }
]

The ! character can be used with or without a regular expression. For example, to match all nodes with a name that is not equal to my_node, you can use the following condition:

matches = [
  {
    node.name = "!my_node"
  }
]

The null value has a special meaning; it checks if the property is not available (or unset). To check if a property is not set:

matches = [
  {
    node.name = null
  }
]

To check the existence of a property, one can use the !null condition, for example:

matches = [
  {
    node.name = "!null"
  }
  {
    node.name = !null            # simplified syntax
  }
]

To handle the "null" string, one needs to escape the string. For example, to check if a property has the string value "null", use:

matches = [
  {
    node.name = "null"
  }
]

To handle anything but the "null" string, use:

matches = [
  {
    node.name = "!\"null\""
  }
  {
    node.name = !"null"      # simplified syntax
  }
]

CONTEXT PROPERTIES RULES

context.properties.rules can be used to dynamically update the properties based on other properties.

A typical case is to update custom settings when running inside a VM. The cpu.vm.name is automatically set when running in a VM with the name of the VM. A match rule can be written to set custom properties like this:

context.properties.rules = [
    {   matches = [ { cpu.vm.name = !null } ]
        actions = {
            update-props = {
                # These overrides are only applied when running in a vm.
                default.clock.min-quantum = 1024
            }
        }
    }
}

NODE RULES

The node.rules are evaluated every time the properties on a node are set or updated. This can be used on the server side to override client set properties on arbitrary nodes.

node.rules provides an update-props action that takes an object with properties that are updated on the node object.

Add a node.rules section in the config file like this:

node.rules = [
    {
        matches = [
            {
                # all keys must match the value. ! negates. ~ starts regex.
                client.name = "jack_simple_client"
            }
        ]
        actions = {
            update-props = {
                node.force-quantum = 512
            }
        }
    }
]

Will set the node.force-quantum property of jack_simple_client to 512.

DEVICE RULES

The device.rules are evaluated every time the properties on a device are set or updated. This can be used on the server side to override client set properties on arbitrary devices.

device.rules provides an update-props action that takes an object with properties that are updated on the device object.

Add a device.rules section in the config file like this:

device.rules = [
    {
        matches = [
            {
                # all keys must match the value. ! negates. ~ starts regex.
                device.name = ""v4l2_device.pci-0000_00_14.0-usb-0_1.2_1.0
            }
        ]
        actions = {
            update-props = {
                device.description = "My Webcam"
            }
        }
    }
]

Will set the device.description property of the device with the given device.name to "My Webcam".

AUTHORS

The PipeWire Developers <https://gitlab.freedesktop.org/pipewire/pipewire/issues>; PipeWire is available from <https://pipewire.org>

SEE ALSO

pipewire(1), pw-mon(1), libpipewire-modules(7) pipewire-pulse.conf(5) pipewire-client.conf(5)