mirrors/pipewire
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/pipewire/pipewire.git synced 2025-11-02 09:01:50 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions

module-echo-cancel: improve docs

Browse source
This commit is contained in:
Wim Taymans 2023-03-08 09:58:21 +01:00
parent ee6866a947
commit af91ae67de
1 changed files with 34 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

41
src/modules/module-echo-cancel.c
View file

@ -44,6 +44,40 @@
* 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:
*
*\code{.unparsed}
* .--------. .---------. .--------. .----------. .-------.
* | mic | --> | capture | --> | | --> | source | --> | app |
* '--------' '---------' | echo | '----------' '-------'
* | cancel |
* .--------. .---------. | | .----------. .---------.
* | app | --> | sink | --> | | --> | playback | --> | speaker |
* '--------' '---------' '--------' '----------' '---------'
*\endcode
* - 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 Options
*
* Options specific to the behavior of this module
@ -103,13 +137,6 @@
*/
/**
* .--------. .---------. .--------. .----------. .-------.
* | source | --> | capture | --> | | --> | source | --> | app |
* '--------' '---------' | echo | '----------' '-------'
* | cancel |
* .--------. .---------. | | .----------. .--------.
* | app | --> | sink | --> | | --> | playback | --> | sink |
* '--------' '---------' '--------' '----------' '--------'
*/
#define NAME "echo-cancel"