pipewire-devices(7)

NAME
pipewire-devices - 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 togther. 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.

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.

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
    UNDOCUMENTED

resample.prefill
    UNDOCUMENTED

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
    UNDOCUMENTED

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 false because many drivers 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 advertize 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).

  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

  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)