Every 30 seconds is to cut a video 3s

Question

I have a 30 minute video. I want to skip 3 seconds every 30 seconds. And continue to the end of the video. And it connects all 30s video together Example: 00:00:00 to 00:30:

Answer 1

The select filter is the most convenient for this,

ffmpeg -i in -vf "select='lt(mod(t,33),30)',setpts=N/FRAME_RATE/TB" -af "aselect='lt(mod(t,33),30)',asetpts=N/SR/TB" out

The video and audio select filters keep the first 30 seconds out of every 33 seconds. If your file doesn't have audio, drop the -af .. option.