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Speed Up or Slow Down a Video with FFmpeg (setpts)

Change a video's playback speed from the command line, adjusting video and audio together.

WindowsvideoaudioffmpegLow risk
Run ffmpeg -i input.mp4 -filter:v "setpts=0.5*PTS" -filter:a "atempo=2.0" output.mp4 for 2x speed — divide PTS by the speed factor you want.

01Command

Command
$ ffmpeg -i input.mp4 -filter:v "setpts=0.5*PTS" -filter:a "atempo=2.0" output.mp4

02What it does

setpts rewrites presentation timestamps: PTS divided by 2 doubles the speed, and multiplying (setpts=2*PTS) halves it into slow motion. atempo adjusts the audio to match and preserves pitch so voices stay natural; the wiki notes its supported range is 0.5–2.0, so for 4x you chain two filters like atempo=2.0,atempo=2.0. Re-encoding is required, so this is slower than stream-copy edits.

03Risk

RiskLow risk
RequirementsFFmpeg is not preinstalled on Windows — install it first with: winget install --id Gyan.FFmpeg
!Warning: Extreme speed changes make speech unintelligible — test with a short clip first.

04Undo

✓No undo needed — this command does not change persistent state.

05Sources

  • FilteringGuide (FFmpeg wiki)
    FFmpeg Trac Wiki · community · 2026-09-17
    Evidence: Shows the setpts=0.5*PTS pattern for 2x video speed-up and notes atempo tempo adjustment with a supported range of 0.5–2.0 (chainable).

Last verified: 2026-09-18 · Category: Media