Speed Up Video with ffmpeg — Snippets

Adjust video playback speed while keeping audio in sync and pitch-natural. Useful for tightening screen recordings, conference talks, or demo videos without sounding like chipmunks.

The command

speed-up-video.sh

SPEED=1.15
INPUT="input.mp4"
OUTPUT="output.mp4"

ffmpeg -i "$INPUT" \
  -filter_complex "[0:v]setpts=PTS/${SPEED}[v];[0:a]atempo=${SPEED}[a]" \
  -map "[v]" -map "[a]" \
  -c:v libx264 -preset fast -crf 22 \
  "$OUTPUT"

How it works

setpts=PTS/${SPEED} — divides video presentation timestamps by the speed factor, making frames appear sooner (faster playback)
atempo=${SPEED} — stretches or compresses the audio stream to match, preserving natural pitch
-map "[v]" -map "[a]" — routes the filtered video and audio streams to the output file
-c:v libx264 -preset fast -crf 22 — re-encodes with H.264 using the fast preset and CRF 22 (visually near-lossless; lower CRF = higher quality, larger file)

Common speed values

Factor	Effect	Use case
`1.15`	Barely noticeable speedup	Trimming dead air from recordings
`1.25`	Slightly faster	Tightening a long demo
`1.5`	Noticeably faster	Compressing a lecture
`2.0`	Double speed	Quick recap or time-lapse
`0.5`	Half speed (slow-mo)	Slowing down a fast sequence

Tips

atempo only supports values between 0.5 and 2.0. For speeds beyond that range, chain multiple atempo filters: atempo=2.0,atempo=2.0 gives 4x speed.
Lower the CRF value (e.g., 18) if you need higher quality at the cost of file size. 22 is a good default.
Change -preset to slower for better compression efficiency when encoding time doesn’t matter.