The classifying properties of a node are use for routing the signal to its destination and
for configuring the settings.
@PAR@ client.conf media.type
The media type contains a broad category of the media that is being processed by the node.
Possible values include "Audio", "Video", "Midi"
@PAR@ client.conf media.category
\parblock
What kind of processing is done with the media. Possible values include:
* Playback: media playback.
* Capture: media capture.
* Duplex: media capture and playback or media processing in general.
* Monitor: a media monitor application. Does not actively change media data but monitors
activity.
* Manager: Will manage the media graph.
\endparblock
@PAR@ client.conf media.role
\parblock
The Use case of the media. Possible values include:
* Movie: Movie playback with audio and video.
* Music: Music listening.
* Camera: Recording video from a camera.
* Screen: Recording or sharing the desktop screen.
* Communication: VOIP or other video chat application.
* Game: Game.
* Notification: System notification sounds.
* DSP: Audio or Video filters and effect processing.
* Production: Professional audio processing and production.
* Accessibility: Audio and Visual aid for accessibility.
* Test: Test program.
\endparblock
@PAR@ client.conf media.class
\parblock
The media class is to classify the stream function. Possible values include:
* Video/Source: a producer of video, like a webcam.
* Video/Sink: a consumer of video, like a display window.
* Audio/Source: a source of audio samples like a microphone.
* Audio/Sink: a sink for audio samples, like an audio card.
* Audio/Duplex: a node that is both a sink and a source.
* Stream/Output/Audio: a playback stream.
* Stream/Input/Audio: a capture stream.
The session manager assigns special meaning to the nodes based on the media.class. Sink or Source
classes are used as targets for Stream classes, etc..
\endparblock
## Scheduling Properties @IDX@ client.conf
@PAR@ client.conf node.latency = 1024/48000
Sets a suggested latency on the node as a fraction. This is just a suggestion, the graph will try to configure this latency or less for the graph. It is however possible that the graph is forced to a higher latency.
@PAR@ client.conf node.lock-quantum = false
\parblock
When this node is active, the quantum of the graph is locked and not allowed to change automatically.
It can still be changed forcibly with metadata or when a node forces a quantum.
JACK clients use this property to avoid unexpected quantum changes.
\endparblock
@PAR@ client.conf node.force-quantum = INTEGER
\parblock
While the node is active, force a quantum in the graph. The last node to be activated with this property wins.
A value of 0 unforces the quantum.
\endparblock
@PAR@ client.conf node.rate = RATE
Suggest a rate (samplerate) for the graph. The suggested rate will only be applied when doing so would not cause
interruptions (devices are idle) and when the rate is in the list of allowed rates in the server.
@PAR@ client.conf node.lock-rate = false
When the node is active, the rate of the graph will not change automatically. It is still possible to force a rate change with metadata or with a node property.
@PAR@ client.conf node.force-rate = RATE
\parblock
When the node is active, force a specific sample rate on the graph. The last node to activate with this property wins.
A RATE of 0 means to force the rate in `node.rate` denominator.
\endparblock
@PAR@ client.conf node.always-process = false
\parblock
When the node is active, it will always be joined with a driver node, even when nothing is linked to the node.
Setting this property to true also implies node.want-driver = true.
This is the default for JACK nodes, that always need their process callback called.
\endparblock
@PAR@ client.conf node.want-driver = true
The node wants to be linked to a driver so that it can start processing. This is the default for streams
and filters since 0.3.51. Nodes that are not linked to anything will still be set to the idle state,
unless node.always-process is set to true.
@PAR@ client.conf node.pause-on-idle = false
@PAR@ client.conf node.suspend-on-idle = false
\parblock
When the node is not linked anymore, it becomes idle. Normally idle nodes keep processing and are suspended by the session manager after some timeout. It is possible to immediately pause a node when idle with this property.
When the session manager does not suspend nodes (or when there is no session manager), the node.suspend-on-idle property can be used instead.
When the node has a target configured and the target is destroyed, destroy the node as well.
This property also inhibits that the node is moved to another sink/source.
Note that if a stream should appear/disappear in sync with the target, a session manager (WirePlumber) script
should be written instead.
\endparblock
@PAR@ client.conf node.passive = false
\parblock
This is a passive node and so it should not keep sinks/sources busy. This property makes the session manager create passive links to the sink/sources. If the node is not otherwise linked (via a non-passive link), the node and the sink it is linked to are idle (and eventually suspended).
This is used for filter nodes that sit in front of sinks/sources and need to suspend together with the sink/source.
\endparblock
@PAR@ client.conf node.link-group = ID
Add the node to a certain link group. Nodes from the same link group are not automatically linked to each other by the session manager. And example is a coupled stream where you don't want the output to link to the input streams, making a useless loop.
@PAR@ client.conf stream.dont-remix = false
Instruct the session manager to not remix the channels of a stream. Normally the stream channel configuration is changed to match the sink/source it is connected to. With this property set to true, the stream will keep its original channel layout and the session manager will link matching channels with the sink.
## Audio Adapter Parameters @IDX@ client.conf
An audio stream (and also audio device nodes) contain an audio adapter that can perform,
sample format, sample rate and channel mixing operations.
### Merger Parameters
The merger is used as the input for a sink device node or a capture stream. It takes the various channels and merges them into a single stream for further processing.
The merger will also provide the monitor ports of the input channels and can
apply a software volume on the monitor signal.
@PAR@ client.conf monitor.channel-volumes = false
The volume of the input channels is applied to the volume of the monitor ports. Normally
the monitor ports expose the raw unmodified signal on the input ports.
### Resampler Parameters
Source, sinks, capture and playback streams contain a high quality adaptive resampler.
It uses [sinc](https://ccrma.stanford.edu/~jos/resample/resample.pdf) based resampling
with linear interpolation of filter banks to perform arbitrary
resample factors. The resampler is activated in the following cases:
* The hardware of a device node does not support the graph samplerate. Resampling will occur
from the graph samplerate to the hardware samplerate.
* The hardware clock of a device does not run at the same speed as the graph clock and adaptive
resampling is required to match the clocks.
* A stream does not have the same samplerate as the graph and needs to be resampled.
* An application wants to activate adaptive resampling in a stream to make it match some other
clock.
PipeWire performs most of the sample conversions and resampling in the client (Or in the case of the PulseAudio server, in the pipewire-pulse server that creates the streams). This ensures all the conversions are offloaded to the clients and the server can deal with one single format for performance reasons.
Below is an explanation of the options that can be tuned in the sample converter.
@PAR@ client.conf resample.quality = 4
\parblock
The quality of the resampler. from 0 to 14, the default is 4.
Increasing the quality will result in better cutoff and less aliasing at the expense of
(much) more CPU consumption. The default quality of 4 has been selected as a good compromise
between quality and performance with no artifacts that are well below the audible range.
See [Infinite Wave](https://src.infinitewave.ca/) for a comparison of the performance.
\endparblock
@PAR@ client.conf resample.disable = false
Disable the resampler entirely. The node will only be able to negotiate with the graph
when the samplerates are compatible.
### Channel Mixer Parameters
Source, sinks, capture and playback streams can apply channel mixing on the incoming signal.
Normally the channel mixer is not used for devices, the device channels are usually exposed as they are. This policy is usually enforced by the session manager, so we refer to its documentation there.
Playback and capture streams are usually configured to the channel layout of the sink/source
they connect to and will thus perform channel mixing.
The channel mixer also implements a software volume. This volume adjustment is performed on the original
channel layout. ex: A stereo playback stream that is up-mixed to 5.1 has 2 a left an right volume control.
@PAR@ client.conf channelmix.disable = false
Disables the channel mixer completely. The stream will only be able to link to compatible
sources/sinks with the exact same channel layout.
@PAR@ client.conf channelmix.min-volume = 0.0
@PAR@ client.conf channelmix.max-volume = 10.0
Gives the min and max volume values allowed. Any volume that is set will be clamped to these
values.
@PAR@ client.conf channelmix.normalize = false
\parblock
Makes sure that during such mixing & resampling original 0 dB level is preserved, so nothing sounds wildly quieter/louder.
While this options prevents clipping, it can in some cases produce too low volume. Increase the
Mixes the low frequency effect channel into the front center or stereo pair. This might enhance the dynamic range of the signal if there is no subwoofer and the speakers can reproduce the low frequency signal.
@PAR@ client.conf channelmix.upmix = true
\parblock
Enables up-mixing of the front center (FC) when the target has a FC channel.
The sum of the stereo channels is used and an optional lowpass filter can be used
(see `channelmix.fc-cutoff`).
Also enabled up-mixing of LFE when `channelmix.lfe-cutoff` is set to something else than 0 and
the target has an LFE channel. The LFE channel is produced by adding the stereo channels.
If `channelmix.upmix` is true, the up-mixing of the rear channels is also enabled and controlled
with the `channelmix-upmix-method` property.
\endparblock
@PAR@ client.conf channelmix.upmix-method = psd
\parblock
3 methods are provided to produce the rear channels in a surround sound:
1. none. No rear channels are produced.
2. simple. Front channels are copied to the rear. This is fast but can produce phasing effects.
3. psd. The rear channels as produced from the front left and right ambient sound (the
difference between the channels). A delay and optional phase shift are added to the rear signal
to make the sound bigger.
\endparblock
@PAR@ client.conf channelmix.lfe-cutoff = 150
Apply a lowpass filter to the low frequency effects. The value is expressed in Hz. Typical subwoofers have a cutoff at around 150 and 200. The default value of 0 disables the feature.
@PAR@ client.conf channelmix.fc-cutoff = 12000
\parblock
Apply a lowpass filter to the front center frequency. The value is expressed in Hz.
Since the front center contains the dialogs, a typical cutoff frequency is 12000 Hz.
This option is only active when the up-mix is enabled.
\endparblock
@PAR@ client.conf channelmix.rear-delay = 12.0
\parblock
Apply a delay in milliseconds when up-mixing the rear channels. This improves
