pipewire-devices

Table of Contents

• RUNTIME SETTINGS
• COMMON NODE PROPERTIES
• COMMON DEVICE PROPERTIES
• AUDIO CONVERTER PROPERTIES
• ALSA PROPERTIES
• BLUETOOTH PROPERTIES
• ALSA CARD PROFILES

PipeWire device and node property reference.

DESCRIPTION

Audio sinks and sources, cameras, Bluetooth endpoints, and other objects have properties that can be set in configuration files or at runtime.

Some of the properties are "common object properties" (e.g. such as node.description) and can be set on all types of devices and nodes. Other properties control settings of a specific type of a device (ALSA, Bluetooth, ...).

All the properties are usually configured in the session manager configuration. For how to configure them, see the session manager documentation.

In minimal PipeWire setups without a session manager, they can be configured via context.objects in pipewire.conf(5).

RUNTIME SETTINGS

The settings of most ALSA and virtual device parameters can be configured also at runtime.

The settings are available in device Props in the params field. They can be seen e.g. using pw-dump <id> for an ALSA device:

{
...
      "Props": [
        {
          ...
          "params": [
              "audio.channels",
              2,
              "audio.rate",
              0,
              "audio.format",
              "UNKNOWN",
              "audio.position",
              "[ FL, FR ]",
              "audio.allowed-rates",
              "[  ]",
              "api.alsa.period-size",
              0,
              "api.alsa.period-num",
              0,
              "api.alsa.headroom",
              0,
              "api.alsa.start-delay",
              0,
              "api.alsa.disable-mmap",
              false,
              "api.alsa.disable-batch",
              false,
              "api.alsa.use-chmap",
              false,
              "api.alsa.multi-rate",
              true,
              "latency.internal.rate",
              0,
              "latency.internal.ns",
              0,
              "clock.name",
              "api.alsa.c-1"
            ]
          }
...

One or more params can be changed using pw-cli(1):

pw-cli s <id> Props '{ params = [ "api.alsa.headroom" 1024 ] }'

These settings are not saved and need to be reapplied for each session manager restart.

COMMON NODE PROPERTIES

The properties listed in Stream properties apply also to sink or source nodes corresponding to real or virtual devices.

In addition:

priority.driver # integer

The priority of choosing this device as the driver in the graph. The driver is selected from all linked devices by selecting the device with the highest priority.

Normally, the session manager assigns higher priority to sources so that they become the driver in the graph. The reason for this is that adaptive resampling should be done on the sinks rather than the source to avoid signal distortion when capturing audio.

priority.session # integer

The priority for selecting this device as the default device.

clock.name # string

The name of the clock. This name is auto generated from the card index and stream direction. Devices with the same clock name will not use a resampler to align the clocks. This can be used to link devices together with a shared word clock.

In Pro Audio mode, nodes from the same device are assumed to have the same clock and no resampling will happen when linked together. So, linking a capture port to a playback port will not use any adaptive resampling in Pro Audio mode.

In Non Pro Audio profile, no such assumption is made and adaptive resampling is done in all cases by default. This can also be disabled by setting the same clock.name on the nodes.

node.param.PARAM = JSON # JSON

Set value of a node Param to a JSON value when the device is loaded. This works similarly as pw-cli(1) set-param command. The PARAM should be replaced with the name of the Param to set, ie. for example node.param.Props = { ... } to set Props.

device.id

ID of the device the node belongs to.

COMMON DEVICE PROPERTIES

These are common properties for devices.

device.name # string

A (unique) name for the device. It can be used by command-line and other tools to identify the device.

device.param.PARAM = JSON # JSON

Set value of a device Param to a JSON value when the device is loaded. This works similarly as pw-cli(1) set-param command. The PARAM should be replaced with the name of the Param to set, ie. for example device.Param.Props = { ... } to set Props.

Other device.* properties: UNDOCUMENTED

AUDIO CONVERTER PROPERTIES

Most audio nodes (ALSA, Bluetooth, ...) have common properties for the audio converter. See pipewire-client.conf(5) stream.properties for explanations.

Node properties

clock.quantum-limit

See pipewire.conf(5)

channelmix.disable

See pipewire-client.conf(5)

channelmix.min-volume

See pipewire-client.conf(5)

channelmix.max-volume

See pipewire-client.conf(5)

channelmix.normalize

See pipewire-client.conf(5)

channelmix.mix-lfe

See pipewire-client.conf(5)

channelmix.upmix

See pipewire-client.conf(5)

channelmix.lfe-cutoff

See pipewire-client.conf(5)

channelmix.fc-cutoff

See pipewire-client.conf(5)

channelmix.rear-delay

See pipewire-client.conf(5)

channelmix.stereo-widen

See pipewire-client.conf(5)

channelmix.hilbert-taps

See pipewire-client.conf(5)

channelmix.upmix-method

See pipewire-client.conf(5)

channelmix.lock-volumes

See pipewire-client.conf(5)

resample.quality

See pipewire-client.conf(5)

resample.disable

See pipewire-client.conf(5)

resample.peaks = false # boolean

Instead of actually resampling, produce peak amplitude values as output. This is used for volume monitoring, where it is set as a property of the "recording" stream.

resample.prefill = false # boolean

Prefill resampler buffers with silence. This affects the initial samples produced by the resampler.

monitor.channel-volumes

See pipewire-client.conf(5)

dither.noise

See pipewire-client.conf(5)

dither.method

See pipewire-client.conf(5)

debug.wav-path

See pipewire-client.conf(5)

adapter.auto-port-config = null # JSON

If specified, configure the ports of the node when it is created, instead of leaving that to the session manager to do. This is useful (only) for minimal configurations without a session manager.

Value is SPA JSON of the form:

{
    mode = "none",          # "none", "passthrough", "convert", "dsp"
    monitor = false,        # boolean
    control = false,        # boolean
    position = "preserve"   # "unknown", "aux", "preserve"
}

See spa_param_port_config for the meaning.

ALSA PROPERTIES

Monitor properties

alsa.use-acp # boolean

Use ALSA Card Profiles (ACP) for device configuration.

alsa.udev.expose-busy # boolean

Expose the ALSA card even if it is busy/in use. Default false. This can be useful when some of the PCMs are in use by other applications but the other free PCMs should still be exposed.

Device properties

api.alsa.path # string

ALSA device path as can be used in snd_pcm_open() and snd_ctl_open().

api.acp.auto-port # boolean

Select reasonable port on device startup. Available for ACP devices.

api.acp.auto-profile # boolean

Select reasonable profile on device startup. Available for ACP devices.

Node properties

audio.channels # integer

The number of audio channels to open the device with. Defaults depends on the profile of the device.

audio.rate # integer

The audio rate to open the device with. Default is 0, which means to open the device with a rate as close to the graph rate as possible.

audio.format # string

The audio format to open the device in. By default this is "UNKNOWN", which will open the device in the best possible bits (32/24/16/8..). You can force a format like S16_LE or S32_LE.

audio.position # JSON array of strings

The audio position of the channels in the device. This is auto detected based on the profile. You can configure an array of channel positions, like "[ FL, FR ]".

audio.allowed-rates # JSON array of integers

The allowed audio rates to open the device with. Default is "[ ]", which means the device can be opened in any supported rate.

Only rates from the array will be used to open the device. When the graph is running with a rate not listed in the allowed-rates, the resampler will be used to resample to the nearest allowed rate.

api.alsa.period-size # integer

The period size to open the device in. By default this is 0, which will open the device in the default period size to minimize latency.

api.alsa.period-num # integer

The amount of periods to use in the device. By default this is 0, which means to use as many as possible.

api.alsa.headroom # integer

The amount of extra space to keep in the ringbuffer. The default is 0. Higher values can be configured when the device read and write pointers are not accurately reported.

api.alsa.start-delay # integer

Some devices require a startup period. The default is 0. Higher values can be set to send silence samples to the device first.

api.alsa.disable-mmap # boolean

Disable mmap operation of the device and use the ALSA read/write API instead. Default is false, mmap is preferred.

api.alsa.disable-batch # boolean

Ignore the ALSA batch flag. If the batch flag is set, ALSA will need an extra period to update the read/write pointers. Ignore this flag from ALSA can reduce the latency. Default is false.

api.alsa.use-chmap # boolean

Use the driver provided channel map. Default is true when using UCM, false otherwise because many driver don't report this correctly.

api.alsa.multi-rate # boolean

Allow devices from the same card to be opened in multiple sample rates. Default is true. Some older drivers did not properly advertise the capabilities of the device and only really supported opening the device in one rate.

api.alsa.htimestamp = false # boolean

Use ALSA htimestamps in scheduling, instead of the system clock. Some ALSA drivers produce bad timestamps, so this is not enabled by default and will be disabled at runtime if it looks like the ALSA timestamps are bad.

api.alsa.htimestamp.max-errors # integer

Specify the number of consecutive errors before htimestamp is disabled. Setting this to 0 makes htimestamp never get disabled.

api.alsa.disable-tsched = false # boolean

Disable timer-based scheduling, and use IRQ for scheduling instead. The "Pro Audio" profile will usually enable this setting, if it is expected it works on the hardware.

api.alsa.auto-link = false # boolean

Link follower PCM devices to the driver PCM device when using IRQ-based scheduling. The "Pro Audio" profile will usually enable this setting, if it is expected it works on the hardware.

latency.internal.rate # integer

Static set the device systemic latency, in samples at playback rate.

latency.internal.ns # integer

Static set the device systemic latency, in nanoseconds.

api.alsa.path # string

UNDOCUMENTED

api.alsa.open.ucm # boolean

Open device using UCM.

api.alsa.bind-ctls # boolean

UNDOCUMENTED

iec958.codecs # JSON array of string

Enable only specific IEC958 codecs. This can be used to disable some codecs the hardware supports. Available values: PCM, AC3, DTS, MPEG, MPEG2-AAC, EAC3, TRUEHD, DTSHD

BLUETOOTH PROPERTIES

Monitor properties

The following are settings for the Bluetooth device monitor, not device or node properties:

bluez5.roles # JSON array of string

Enabled roles (default: [ a2dp_sink a2dp_source bap_sink bap_source hfp_hf hfp_ag ])

Currently some headsets (Sony WH-1000XM3) are not working with both hsp_ag and hfp_ag enabled, so by default we enable only HFP.

Supported roles:

• hsp_hs (HSP Headset),
• hsp_ag (HSP Audio Gateway),
• hfp_hf (HFP Hands-Free),
• hfp_ag (HFP Audio Gateway)
• a2dp_sink (A2DP Audio Sink)
• a2dp_source (A2DP Audio Source)
• bap_sink (LE Audio Basic Audio Profile Sink)
• bap_source (LE Audio Basic Audio Profile Source)

bluez5.codecs # JSON array of string

Enabled A2DP codecs (default: all). Possible values: sbc sbc_xq aac aac_eld aptx aptx_hd aptx_ll aptx_ll_duplex faststream faststream_duplex lc3plus_h3 ldac opus_05 opus_05_51 opus_05_71 opus_05_duplex opus_05_pro opus_g lc3

bluez5.default.rate # integer

Default audio rate.

bluez5.default.channels # integer

Default audio channels.

bluez5.hfphsp-backend # integer

HFP/HSP backend (default: native). Available values: any, none, hsphfpd, ofono, native

bluez5.hfphsp-backend-native-modem # string

bluez5.dummy-avrcp player # boolean

Register dummy AVRCP player. Some devices have wrongly functioning volume or playback controls if this is not enabled. Default: false

bluez5.enable-sbc-xq # boolean

Override device quirk list and enable SBC-XQ for devices for which it is disabled.

bluez5.enable-msbc # boolean

Override device quirk list and enable MSBC for devices for which it is disabled.

bluez5.enable-hw-volume # boolean

Override device quirk list and enable hardware volume fo devices for which it is disabled.

bluez5.hw-offload-sco # boolean

HFP/HSP hardware offload SCO support (default: false).

This feature requires a custom configuration that routes SCO audio to ALSA nodes, in a platform-specific way. See tests/examples/bt-pinephone.lua in WirePlumber for an example. Do not enable this setting if you don't know what all this means, as it won't work.

bluez5.a2dp.opus.pro.channels = 3 # integer

PipeWire Opus Pro audio profile channel count.

bluez5.a2dp.opus.pro.coupled-streams = 1 # integer

PipeWire Opus Pro audio profile coupled stream count.

bluez5.a2dp.opus.pro.locations = "FL,FR,LFE" # string

PipeWire Opus Pro audio profile audio channel locations.

bluez5.a2dp.opus.pro.max-bitrate = 600000 # integer

PipeWire Opus Pro audio profile max bitrate.

bluez5.a2dp.opus.pro.frame-dms = 50 # integer

PipeWire Opus Pro audio profile frame duration (1/10 ms).

bluez5.a2dp.opus.pro.bidi.channels = 1 # integer

PipeWire Opus Pro audio profile duplex channels.

bluez5.a2dp.opus.pro.bidi.coupled-streams = 0 # integer

PipeWire Opus Pro audio profile duplex coupled stream count.

bluez5.a2dp.opus.pro.bidi.locations = "FC" # string

PipeWire Opus Pro audio profile duplex coupled channel locations.

bluez5.a2dp.opus.pro.bidi.max-bitrate = 160000 # integer

PipeWire Opus Pro audio profile duplex max bitrate.

bluez5.a2dp.opus.pro.bidi.frame-dms = 400 # integer

PipeWire Opus Pro audio profile duplex frame duration (1/10 ms).

bluez5.bcast_source.config # JSON

Example:

bluez5.bcast_source.config = [
  {
    "broadcast_code": "Børne House",
    "encryption: false,
    "bis": [
      { # BIS configuration
        "qos_preset": "16_2_1", # QOS preset name from table Table 6.4 from BAP_v1.0.1.
        "audio_channel_allocation": 1, # audio channel allocation configuration for the BIS
        "metadata": [ # metadata configurations for the BIS
           { "type": 1, "value": [ 1, 1 ] }
        ]
      }
    ]
  }
]

Device properties

bluez5.auto-connect # boolean

Auto-connect devices on start up. Disabled by default if the property is not specified.

bluez5.hw-volume = [ PROFILE1 PROFILE2... ] # JSON array of string

Profiles for which to enable hardware volume control (default: [ hfp_ag hsp_ag a2dp_source ]).

bluez5.profile # string

Initial device profile. This usually has no effect as the session manager overrides it.

bluez5.a2dp.ldac.quality # string

LDAC encoding quality Available values:

• auto (Adaptive Bitrate, default)
• hq (High Quality, 990/909kbps)
• sq (Standard Quality, 660/606kbps)
• mq (Mobile use Quality, 330/303kbps)

bluez5.a2dp.aac.bitratemode # integer

AAC variable bitrate mode. Available values: 0 (cbr, default), 1-5 (quality level)

bluez5.a2dp.opus.pro.application = "audio" # string

PipeWire Opus Pro Audio encoding mode: audio, voip, lowdelay

bluez5.a2dp.opus.pro.bidi.application = "audio" # string

PipeWire Opus Pro Audio duplex encoding mode: audio, voip, lowdelay

bluez5.bap.cig = auto # integer, or 'auto'

Set CIG ID for BAP unicast streams of the device. Default: "auto" (automatic).

Node properties

bluez5.media-source-role # string

Media source role for Bluetooth clients connecting to this instance. Available values:

• playback: playing stream to speakers
• input: appear as source node.

ALSA CARD PROFILES

The sound card profiles ("Analog stereo", "Analog stereo duplex", ...) except "Pro Audio" come from two sources:

• UCM: ALSA Use Case Manager: the profile configuration system from ALSA. See https://github.com/alsa-project/alsa-ucm-conf/
• ACP ("Alsa Card Profiles"): Pulseaudio's profile system ported to PipeWire. See https://www.freedesktop.org/wiki/Software/PulseAudio/Backends/ALSA/Profiles/

See the above links on how to configure these systems.

For ACP, PipeWire looks for the profile configuration files under

• ~/.config/alsa-card-profile
• /etc/alsa-card-profile
• /usr/share/alsa-card-profile/mixer`.

The path and profile-set files are in subdirectories paths and profile-sets of these directories. It is possible to override individual files locally by putting a modified copy into the ACP directories under ~/.config or /etc.

AUTHORS

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

SEE ALSO

pipewire.conf(5)