Filery

Change Video Speed

Speed up or slow down a clip. Pitch correction keeps speech sounding natural.

Choose video file or drop it anywhere on this page MP4 · MOV · WEBM · MKV · AVI · WMV · FLV · M4V · 3GP · MPEG · +3 Processed on your device — never uploaded

How to change video speed

  1. Drop a video in.
  2. Pick a speed from the presets or use the slider for a specific multiplier.
  3. Enable pitch correction to keep voices sounding natural, then download.

About this tool

Changing video speed sounds like a simple operation — multiply the frame duration — and at the video level it mostly is. The complication is audio. A raw speed change shifts pitch along with tempo: double speed plays an octave higher, half speed drops an octave. For music and speech that is usually unacceptable. Pitch correction (time-domain pitch shifting) separates the two, adjusting tempo while keeping pitch stable. The quality of this separation degrades at extreme ratios, but in the range most editors actually use it is transparent.

True slow motion requires the source to have been recorded at a high frame rate. Slowing a standard 30 fps clip means the same frames are displayed longer, and motion will look choppy for anything faster than a gentle pan. High-speed recording — 60, 120 or 240 fps — is what gives the smooth slow-motion look because there are genuinely more frames to stretch across the same playback time.

Questions

How slow can I go before the result looks bad?
True slow motion (where each original frame is shown for longer without interpolating new frames) works cleanly to any speed if the source has enough frame rate. Slowing a 30 fps clip to 0.25× plays each frame for four times as long, which produces a visibly jittery result. A 120 fps source slowed to 0.25× plays at the equivalent of 30 fps — smooth. If you need smooth slow motion from 30 fps footage, a frame-interpolation tool is required, which this is not.
Does pitch correction work at all speeds?
Pitch correction uses a time-stretching algorithm to separate pitch from tempo. It works well between about 0.5× and 2×, where the artefacts are minimal. Beyond those limits the algorithm introduces audible warbling, and at 4× the audio is largely unusable regardless — that is why the mute toggle is useful for time-lapse outputs.