tremolo

Watch on youtube.com

doc

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

see also

vibrato, apulsator

Sinusoidal amplitude modulation (simplest emurating of tremolo).

[me@host: ~]$ ffplay -f lavfi 'sine=440:d=10,tremolo=f=2:d=0.5'

[me@host: ~]$ ffplay some.mp4 -af 'tremolo=f=10:d=0.7'

Each segment of the uploaded video was created with the following script:

#! /bin/sh
ffmpeg -hide_banner -y -filter_complex "
sine=440:d=8
,tremolo=f=2:d=0.5
,aformat=sample_fmts=u8|s16:channel_layouts=stereo
,asplit=3[out1][a1][a2];
[a1]ahistogram=s=1280x360[vt];
[a2]showcqt=s=1280x360[vb];
[vt][vb]vstack,format=yuv420p
,drawtext=fontsize=40:fontcolor=white:x=500:y=240:text=%{pts}
[out0]
" -map '[out0]' -map '[out1]' out.mp4