The following is my cheat sheet for basic video editing with ffmpeg

split

When I want to split a video input.mkv from 10s to 30s and save it as output.mkv:

ffmpeg -i input.mkv -ss 10 -t 30 -vcodec copy -acodec copy output.mkv

concatenate

Let's say, I want to join (concatenate) 2 video (or audio) files: part1.mkv, part2.mkv into a single file: joined.mkv. I will first create a file: input.txt with the following content:

file part1.mkv
file part2.mkv

and then execute the following

ffmpeg -f concat -i input.txt -vcodec copy -acodec copy joined.mkv

add audio to video

When I want to superimpose an audio track on top of a video track:

ffmpeg -i video.mkv -i audio.ogg -c:v copy -c:a copy output.mkv

speed up

If I want to speed up a video input.mkv 4 times, I will do the following:

ffmpeg -i input.mkv -filter:v "setpts=0.25*PTS" output_4x.mkv

strip audio from a video

ffmpeg -i [input_file] -vcodec copy -an [output_file]