1libpipewire-module-echo-Mciasncceelll(a7n)eous InformatiloinbpMiapneuwailre-module-echo-cancel(7)
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6 libpipewire-module-echo-cancel - Echo Cancel
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9 The echo-cancel module performs echo cancellation.
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11 The module creates virtual echo-cancel-capture source and echo-cancel-
12 playback sink nodes and the associated streams.
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14 The echo-cancel module is mostly used in video or audio conference
15 applications. When the other participants talk and the audio is going
16 out to the speakers, the signal will be picked up again by the
17 microphone and sent back to the other participants (along with your
18 talking), resulting in an echo. This is annoying because the other
19 participants will hear their own echo from you.
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21 Conceptually the echo-canceler is composed of 4 streams:
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23 .--------. .---------. .--------. .----------. .-------.
24 | mic | --> | capture | --> | | --> | source | --> | app |
25 | cancel |
26 .--------. .---------. | | .----------. .---------.
27 | app | --> | sink | --> | | --> | playback | --> | speaker |
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29 • A capture stream that captures audio from a microphone.
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31 • A Sink that takes the signal containing the data that should be
32 canceled out from the capture stream. This is where the application
33 (video conference application) send the audio to and it contains the
34 signal from the other participants that are speaking and that needs
35 to be cancelled out.
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37 • A playback stream that just passes the signal from the Sink to the
38 speaker. This is so that you can hear the other participants. It is
39 also the signal that gets picked up by the microphone and that
40 eventually needs to be removed again.
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42 • A Source that exposes the echo-canceled data captured from the
43 capture stream. The data from the sink stream and capture stream are
44 correlated and the signal from the sink stream is removed from the
45 capture stream data. This data then goes into the application (the
46 conference application) and does not contain the echo from the other
47 participants anymore.
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50 libpipewire-module-echo-cancel
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53 Options specific to the behavior of this module
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55 • capture.props = {}: properties to be passed to the capture stream
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57 • source.props = {}: properties to be passed to the source stream
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59 • sink.props = {}: properties to be passed to the sink stream
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61 • playback.props = {}: properties to be passed to the playback stream
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63 • library.name = <str>: the echo cancellation library Currently
64 supported: aec/libspa-aec-webrtc. Leave unset to use the default
65 method (aec/libspa-aec-webrtc).
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67 • aec.args = <str>: arguments to pass to the echo cancellation method
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69 • monitor.mode: Instead of making a sink, make a stream that captures
70 from the monitor ports of the default sink.
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73 Options with well-known behavior:
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75 • audio.rate
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77 • audio.channels
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79 • audio.position
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81 • media.class
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83 • node.latency
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85 • node.name
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87 • node.description
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89 • node.group
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91 • node.link.group
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93 • node.virtual
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95 • node.latency
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97 • remote.name
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100 context.modules = [
101 { name = libpipewire-module-echo-cancel
102 args = {
103 # library.name = aec/libspa-aec-webrtc
104 # node.latency = 1024/48000
105 # monitor.mode = false
106 capture.props = {
107 node.name = "Echo Cancellation Capture"
108 }
109 source.props = {
110 node.name = "Echo Cancellation Source"
111 }
112 sink.props = {
113 node.name = "Echo Cancellation Sink"
114 }
115 playback.props = {
116 node.name = "Echo Cancellation Playback"
117 }
118 }
119 }
120 ]
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122PipeWire 1.0.0 libpipewire-module-echo-cancel(7)