doytsujin / remsi

Remove silence from video files with a 1-line ffmpeg command

Remsi

Remove silence from video files with a one-line ffmpeg command.

Why

Apparently it's not possible to automatically remove silent part from a video file in one go with ffmpeg. The silencedetect audio filter only detects silence, and the silenceremove filter is an audio filter that only works on audio and doesn't remove corresponding video parts.

How

What this does is take as input the output of silencedetect and simply writes the corresponding audio and video select filters for ffmpeg. Then the command produces a video file with the silent parts removed.

Install & Use

Requires ffmpeg, Python3. Usage is as follows:

ffmpeg -i YOURINPUTFILE -hide_banner -af silencedetect=n=-50dB:d=1 -f null - 2>&1 | python remsi.py > COMMANDFILENAME

silencedetect filter accepts a noise level in dB and a minimum duration in seconds.

YOURINPUTFILE is the name of your input file (video or audio file: 'noise_a.mp4' for example).

COMMANDFILENAME is the name of the file you want to write the ffmpeg command to. After the execution of the above command, it will contain an ffmpeg command such as (for example):

ffmpeg -i noise_a.mp4 -vf "select='between(t,0,2.00093)+between(t,4.00009,6.00256)+between(t,7.99961,9.99989)+between(t,12.0001,13.9998)',setpts=N/FRAME_RATE/TB" -af "aselect='between(t,0,2.00093)+between(t,4.00009,6.00256)+between(t,7.99961,9.99989)+between(t,12.0001,13.9998)',asetpts=N/SR/TB" outfile_noise_a.mp4

This is actually a succession of select filters. Once run, it will output (reencode) a video file with the silent parts removed.