aecho

Watch on youtube.com

doc

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

This filter applies echoing to the input audio.

It is good to start with the following style:

[me@host: ~]$ ffplay snd.wav -af "
> aecho=
>   in_gain=0.6
>   :out_gain=0.3
>   :delays='10'
>   :decays='0.9'"

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

[me@host: ~]$ ffplay snd.wav -af "
> aecho=
>   in_gain=0.6
>   :out_gain=0.3
>   :delays='  10|  100|  1000|  1500'
>   :decays=' 0.9|  0.5|   0.2|   0.1'"
[me@host: ~]$ ffplay -f lavfi "
> amovie=snd.wav
> , aecho=
>   in_gain=0.6
>   :out_gain=0.3
>   :delays='  10|  100|  1000|  1500'
>   :decays=' 0.9|  0.5|   0.2|   0.1'"

see also

adelay, chorus