NAME

       libpipewire-module-echo-cancel - Echo Cancel

DESCRIPTION

       The echo-cancel module performs echo cancellation.

       The module creates virtual echo-cancel-capture source and echo-cancel-playback sink nodes
       and the associated streams.

       The echo-cancel module is mostly used in video or audio conference applications. When the
       other participants talk and the audio is going out to the speakers, the signal will be
       picked up again by the microphone and sent back to the other participants (along with your
       talking), resulting in an echo. This is annoying because the other participants will hear
       their own echo from you.

       Conceptually the echo-canceler is composed of 4 streams:

       .--------.     .---------.     .--------.     .----------.     .-------.
       |  mic   | --> | capture | --> |        | --> |  source  | --> |  app  |
                                      | cancel |
       .--------.     .---------.     |        |     .----------.     .---------.
       |  app   | --> |  sink   | --> |        | --> | playback | --> | speaker |

       • A capture stream that captures audio from a microphone.

       • A Sink that takes the signal containing the data that should be canceled out from the
         capture stream. This is where the application (video conference application) send the
         audio to and it contains the signal from the other participants that are speaking and
         that needs to be cancelled out.

       • A playback stream that just passes the signal from the Sink to the speaker. This is so
         that you can hear the other participants. It is also the signal that gets picked up by
         the microphone and that eventually needs to be removed again.

       • A Source that exposes the echo-canceled data captured from the capture stream. The data
         from the sink stream and capture stream are correlated and the signal from the sink
         stream is removed from the capture stream data. This data then goes into the application
         (the conference application) and does not contain the echo from the other participants
         anymore.

MODULE NAME

       libpipewire-module-echo-cancel

MODULE OPTIONS

       Options specific to the behavior of this module

       • capture.props = {}: properties to be passed to the capture stream

       • source.props = {}: properties to be passed to the source stream

       • sink.props = {}: properties to be passed to the sink stream

       • playback.props = {}: properties to be passed to the playback stream

       • library.name = <str>: the echo cancellation library Currently supported: aec/libspa-aec-
         webrtc. Leave unset to use the default method (aec/libspa-aec-webrtc).

       • aec.args = <str>: arguments to pass to the echo cancellation method

       • monitor.mode: Instead of making a sink, make a stream that captures from the monitor
         ports of the default sink.

GENERAL OPTIONS

       Options with well-known behavior:

       • audio.rate

       • audio.channels

       • audio.position

       • media.class

       • node.latency

       • node.name

       • node.description

       • node.group

       • node.link.group

       • node.virtual

       • node.latency

       • remote.name

EXAMPLE CONFIGURATION

        context.modules = [
         {   name = libpipewire-module-echo-cancel
             args = {
                 # library.name  = aec/libspa-aec-webrtc
                 # node.latency = 1024/48000
                 # monitor.mode = false
                 capture.props = {
                    node.name = "Echo Cancellation Capture"
                 }
                 source.props = {
                    node.name = "Echo Cancellation Source"
                 }
                 sink.props = {
                    node.name = "Echo Cancellation Sink"
                 }
                 playback.props = {
                    node.name = "Echo Cancellation Playback"
                 }
             }
         }
       ]