chorus

doc

https://ffmpeg.org/ffmpeg-filters.html#chorus

This filter applies chorus effect to the input audio.

It is good to start with the following style:

#! /bin/sh
ffplay snd.wav -af "
chorus=
in_gain=0.5
:out_gain=0.9
:delays=' 50'
:decays='  0.4'
:speeds='  0.25'
:depths='  2'"

This allows you to write filter graphs that are easy to read and maintain, even for the following complex ones:

#! /bin/sh
ffplay snd.wav -af "
chorus=
in_gain=0.5
:out_gain=0.9
:delays=' 50    | 60    | 40'
:decays='  0.4  |  0.32 |  0.3'
:speeds='  0.25 |  0.4  |  0.3'
:depths='  2    |  2.3  |  1.3'"
#! /bin/sh
ffplay -f lavfi "
amovie=snd.wav
, chorus=
in_gain=0.5
:out_gain=0.9
:delays=' 50    | 60    | 40'
:decays='  0.4  |  0.32 |  0.3'
:speeds='  0.25 |  0.4  |  0.3'
:depths='  2    |  2.3  |  1.3'"

By the way, I personally think that this filter is the hardest to use in the world. A very similar thing can be achieved with aecho, so it’s probably better to use it in preferentially.

see also

adelay, aecho