Various tools and commands for video editing and cropping.
ffmpeg -i in.mp4 -filter:v "crop=W_:H_:W_:H_" Vid-out.mp4
ffmpeg -i ORIGINALFILE.mp4 -acodec copy -vcodec copy -ss START -t LENGTH OUTFILE.mp4
ffmpeg -i input.mp4 -c copy output.mkv
ffmpeg -stream_loop 4 -i output.mkv -c copy output.mp4