About Change Speed
Speed up boring sections, create slow-motion drama, or build a time-lapse, anywhere between 0.25× and 4× the original speed.
How change speed works
Speed adjustment can either change the frame rate (faster playback but fewer interpolated frames) or change the playback timestamp metadata (smooth playback, original frame count). NextConvert defaults to the smoother option and uses frame blending for extreme slowdowns so motion stays fluid instead of stuttering.
Audio gets its own treatment. By default we use a phase-vocoder algorithm that preserves pitch, so your speech doesn’t turn chipmunk-high at 2× or basement-deep at 0.5×. If you actually want the chipmunk effect for a meme, toggle pitch-shift on.
Common applications: speed up a 30-minute lecture so you can review at 1.5×, slow down a sports clip to study form, build a 24-hour time-lapse out of a long shot, or compress a tutorial’s slow sections without losing the explanation.
When to use it
Speed up a lecture
Crank a long recording to 1.5× or 2× to save time without losing the audio. Pitch stays natural.
Slow-motion replay
Drop to 0.5× or 0.25× to dissect a sports play, a dance move, or a physics experiment.
Time-lapse
Compress a multi-hour stationary recording into a 30-second time-lapse at 50×. Same engine, just with the cap raised.
Comedic effect
Add chipmunk voices for memes, or slow-mo for dramatic emphasis in edits.
Supported formats
Input
Output
Step-by-step guide
- 1
Upload the video
Drop in any common video format.
- 2
Choose a speed
Preset (0.25×, 0.5×, 1.5×, 2×, 4×) or enter a custom multiplier. Toggle pitch preservation on or off.
- 3
Process and download
We re-encode with the new timing and audio treatment. Download the resulting clip.
Tips for the best result
- For lectures, 1.5× is usually fine. 2× starts to feel rushed, so test the first few minutes before committing.
- Slowdowns past 0.25× look noticeably stuttery unless the source is recorded at a high frame rate (60+ fps).
- Time-lapses look best from a tripod. Any handheld motion gets amplified at high speeds.
Privacy and security
Files are uploaded to our processing servers over an encrypted connection and removed automatically after the job completes (usually within a few hours). We never share your media or train models on it. You can also delete a job manually at any time from your dashboard.
Read our full privacy policy for retention timelines and our list of subprocessors.