Create a timelapse from a long video
useful tips
// what it does
Speeds the video up 30x by dividing every frame's presentation timestamp with setpts=PTS/30, and -an drops the audio (which can't be time-scaled the same way). Each frame is simply shown for a thirtieth of its original duration, compressing a long clip into a short timelapse. Handy for screen recordings or static-camera footage where you want the fast-forward feel in one pass.
// shell
$ ffmpeg -i input.mp4 -vf "setpts=PTS/30" -an output.mp4// gotcha
setpts only rescales timestamps — it keeps every source frame, so a 30 fps clip becomes ~900 fps and can balloon in encode cost or get clamped by the player; to actually drop frames use the fps or select filter (or set -r) instead of relying on PTS alone.