jack.conf

Table of Contents

• CONFIGURATION FILE SECTIONS
• JACK PROPERTIES
• MATCH RULES
• ENVIRONMENT VARIABLES

The PipeWire JACK client configuration file.

SYNOPSIS

$XDG_CONFIG_HOME/pipewire/jack.conf

/etc/pipewire/jack.conf

/usr/share/pipewire/jack.conf

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

/etc/pipewire/jack.conf.d/

$XDG_CONFIG_HOME/pipewire/jack.conf.d/

DESCRIPTION

Configuration for PipeWire JACK clients.

The configuration file format and lookup logic is the same as for pipewire.conf(5).

Drop-in configuration files jack.conf.d/*.conf can be used, and are recommended. See pipewire.conf(5).

CONFIGURATION FILE SECTIONS

jack.properties

JACK client configuration.

jack.rules

JACK client match rules.

In addition, the PipeWire context configuration sections may also be specified, see pipewire.conf(5).

JACK PROPERTIES

The configuration file can contain an extra JACK specific section called jack.properties like this:

...
jack.properties = {
    #rt.prio             = 88
    #node.latency        = 1024/48000
    #node.lock-quantum   = true
    #node.force-quantum  = 0
    #jack.show-monitor   = true
    #jack.merge-monitor  = true
    #jack.show-midi      = true
    #jack.short-name     = false
    #jack.filter-name    = false
    #jack.filter-char    = " "
    #
    # allow:           Don't restrict self connect requests
    # fail-external:   Fail self connect requests to external ports only
    # ignore-external: Ignore self connect requests to external ports only
    # fail-all:        Fail all self connect requests
    # ignore-all:      Ignore all self connect requests
    #jack.self-connect-mode  = allow
    #jack.locked-process     = true
    #jack.default-as-system  = false
    #jack.fix-midi-events    = true
    #jack.global-buffer-size = false
    #jack.passive-links      = false
    #jack.max-client-ports   = 768
    #jack.fill-aliases       = false
    #jack.writable-input     = false
 
}

See stream.properties in pipewire-client.conf(5) for an explanation of the generic node properties.

It is also possible to have per-client settings, see Match Rules below.

rt.prio

To limit the realtime priority that jack clients can acquire.

node.latency

To force a specific minimum buffer size for the JACK applications, configure:

node.latency = 1024/48000

This configures a buffer-size of 1024 samples at 48KHz. If the graph is running at a different sample rate, the buffer-size will be adjusted accordingly.

node.lock-quantum

To make sure that no automatic quantum is changes while JACK applications are running, configure:

node.lock-quantum = true

The quantum can then only be changed by metadata or when an application is started with node.force-quantum. JACK Applications will also be able to use jack_set_buffersize() to override the quantum.

node.force-quantum

To force the quantum to a certain value and avoid changes to it:

node.force-quantum = 1024

The quantum can then only be changed by metadata or when an application is started with node.force-quantum (or JACK applications that use jack_set_buffersize() to override the quantum).

jack.show-monitor

Show the Monitor client and its ports.

jack.merge-monitor

Exposes the capture ports and monitor ports on the same JACK device client. This is how JACK presents monitor ports to the clients. The default is however not to merge them together because this results in more user friendly user interfaces, usually. An extra client with a Monitor suffix is created that contains the monitor ports.

For example, this is (part of) the output of jack_lsp with the default setting (jack.merge-monitor = false):

Compare:

jack.merge-monitor = true	jack.merge-monitor = false
Built-in Audio Analog Stereo:playback_FL	Built-in Audio Analog Stereo:playback_FL
Built-in Audio Analog Stereo:monitor_FL	Built-in Audio Analog Stereo Monitor:monitor_FL
Built-in Audio Analog Stereo:playback_FR	Built-in Audio Analog Stereo:playback_FR
Built-in Audio Analog Stereo:monitor_FR	Built-in Audio Analog Stereo Monitor:monitor_FR

jack.show-midi

Show the MIDI clients and their ports.

jack.short-name

To use shorter names for the device client names use jack.short-name = true. Compare:

jack.short-name = true	jack.short-name = false
HDA Intel PCH:playback_FL	Built-in Audio Analog Stereo:playback_FL
HDA Intel PCH Monitor:monitor_FL	Built-in Audio Analog Stereo Monitor:monitor_FL
HDA Intel PCH:playback_FR	Built-in Audio Analog Stereo:playback_FR
HDA Intel PCH Monitor:monitor_FR	Built-in Audio Analog Stereo Monitor:monitor_FR

jack.filter-name

jack.filter-char

Will replace all special characters with jack.filter-char. For clients the special characters are ()[].:*$ and for ports they are ()[].*$. Use this option when a client is not able to deal with the special characters. (and older version of PortAudio was known to use the client and port names as a regex, and thus failing when there are regex special characters in the name).

jack.self-connect-mode

Restrict a client from making connections to and from itself. Possible values and their meaning are summarized as:

Value	Behavior
allow	Don't restrict self connect requests.
fail-external	Fail self connect requests to external ports only.
ignore-external	Ignore self connect requests to external ports only.
fail-all	Fail all self connect requests.
ignore-all	Ignore all self connect requests.

jack.locked-process

Make sure the process and callbacks can not be called at the same time. This is the normal operation but it can be disabled in case a specific client can handle this.

jack.default-as-system

Name the default source and sink as system and number the ports to maximize compatibility with JACK programs.

jack.default-as-system = false	jack.default-as-system = true
HDA Intel PCH:playback_FL	system:playback_1
HDA Intel PCH Monitor:monitor_FL	system:monitor_1
HDA Intel PCH:playback_FR	system:playback_2
HDA Intel PCH Monitor:monitor_FR	system:monitor_2

jack.fix-midi-events

Fix NoteOn events with a 0 velocity to NoteOff. This is standard behaviour in JACK and is thus enabled by default to maximize compatibility. Especially LV2 plugins do not allow NoteOn with 0 velocity.

jack.global-buffer-size

When a client has this option, buffersize changes will be applied globally and permanently for all PipeWire clients using the metadata.

jack.passive-links

Makes JACK clients make passive links. This option only works when the server link-factory was configured with the allow.link.passive option.

jack.max-client-ports

Limit the number of allowed ports per client to this value.

jack.fill-aliases

Automatically set the port alias1 and alias2 on the ports.

jack.writable-input

Makes the input buffers writable. This is the default because some JACK clients write to the input buffer. This however can cause corruption in other clients when they are also reading from the buffer.

Set this to true to avoid buffer corruption if you are only dealing with non-buggy clients.

MATCH RULES

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

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

jack.rules = [
    {
        matches = [
            {
                # all keys must match the value. ! negates. ~ starts regex.
                application.process.binary = "jack_simple_client"
            }
        ]
        actions = {
            update-props = {
                node.latency = 512/48000
            }
        }
    }
    {
        matches = [
            {
                client.name = "catia"
            }
        ]
        actions = {
            update-props = {
                jack.merge-monitor = true
            }
        }
    }
]

Will set the latency of jack_simple_client to 512/48000 and makes Catia see the monitor client merged with the playback client.

ENVIRONMENT VARIABLES

See pipewire(1) for common environment variables. Many of these also apply to JACK client applications.

Environment variables can be used to control the behavior of the PipeWire JACK client library.

PIPEWIRE_NOJACK

PIPEWIRE_INTERNAL

When any of these variables is set, the JACK client library will refuse to open a client. The PIPEWIRE_INTERNAL variable is set by the PipeWire main daemon to avoid self connections.

PIPEWIRE_PROPS

Adds/overrides the properties specified in the jack.conf file. Check out the output of this:

> PIPEWIRE_PROPS='{ jack.short-name=true jack.merge-monitor=true }' jack_lsp
...
HDA Intel PCH:playback_FL
HDA Intel PCH:monitor_FL
HDA Intel PCH:playback_FR
HDA Intel PCH:monitor_FR
...

PIPEWIRE_LATENCY

PIPEWIRE_LATENCY=<samples>/<rate> <application>

A quick way to configure the maximum buffer-size for a client. It will run this client with the specified buffer-size (or smaller).

PIPEWIRE_LATENCY=256/48000 jack_lsp is equivalent to ‘PIPEWIRE_PROPS=’{ node.latency=256/48000 }' jack_lsp`

A better way to start a jack session in a specific buffer-size is to force it with:

pw-metadata -n settings 0 clock.force-quantum <quantum>

This always works immediately and the buffer size will not change until the quantum is changed back to 0.

PIPEWIRE_RATE

PIPEWIRE_RATE=1/<rate> <application>

A quick way to configure the rate of the graph. It will try to switch the samplerate of the graph. This can usually only be done with the graph is idle and the rate is part of the allowed sample rates.

PIPEWIRE_RATE=1/48000 jack_lsp is equivalent to ‘PIPEWIRE_PROPS=’{ node.rate=1/48000 }' jack_lsp`

A better way to start a jack session in a specific rate is to force the rate with:

pw-metadata -n settings 0 clock.force-rate <rate>

This always works and the samplerate does not need to be in the allowed rates. The rate will also not change until it is set back to 0.

PIPEWIRE_QUANTUM

PIPEWIRE_QUANTUM=<buffersize>/<rate> <application>

Is similar to using PIPEWIRE_LATENCY=<buffersize>/<rate> and PIPEWIRE_RATE=1/<rate> (see above), except that it is not just a suggestion but it actively forces the graph to change the rate and quantum. It can be used to set both a buffersize and samplerate at the same time.

When 2 applications force a quantum, the last one wins. When the winning app is stopped, the quantum of the previous app is restored.

PIPEWIRE_LINK_PASSIVE

PIPEWIRE_LINK_PASSIVE=true qjackctl

Make this client create passive links only. All links created by the client will be marked passive and will not keep the sink/source busy.

You can use this to link filters to devices. When there is no client connected to the filter, only passive links remain between the filter and the device and the device will become idle and suspended.

PIPEWIRE_NODE

PIPEWIRE_NODE=<id> <application>

Will sort the ports so that only the ports of the node with <id> are listed. You can use this to force an application to only deal with the ports of a certain node, for example when auto connecting.

AUTHORS

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

SEE ALSO

pw-jack(1), pipewire.conf(5)