#!/bin/sh
# Run in the folder containing source-30s.mp4.
# This silent source has no audio stream. The command creates a new output.
set -eu
ffmpeg -i source-30s.mp4 -filter_complex '[0:v]split=2[a][b];[a]trim=start=4:end=20,setpts=PTS-STARTPTS[first];[b]trim=start=24:end=30,setpts=PTS-STARTPTS[second];[first][second]concat=n=2:v=1:a=0,fps=24[out]' -map '[out]' -an -c:v libx264 -crf 22 -pix_fmt yuv420p -movflags +faststart context-cut-rebuilt.mp4