Choose 0.5× or 0.75× to slow a video down, or 1.25×, 1.5× or 2× to speed it up. Expected duration is original duration divided by speed. Mediaivo creates a new MP4; changing speed does not just change a player preference.
Export a video at a different speed
Upload the original clip, choose one speed and download a separate MP4.
How long will the new video be?
| Speed | Expected output | Typical reason |
|---|---|---|
| 0.5× | 120 seconds | Study a brief movement. |
| 0.75× | 80 seconds | Slow an explanation moderately. |
| 1.25× | 48 seconds | Shorten a demonstration. |
| 1.5× | 40 seconds | Move through repetitive steps. |
| 2× | 30 seconds | Show a process more quickly. |
What happens to the sound?
When the source has audio, the tool adjusts its tempo along with the video. It uses tempo processing rather than a simple sample-rate change; still listen for artifacts and check lip sync. A silent source stays silent. The new video is H.264 MP4 with AAC audio when an audio stream is present.
A separate subtitle file does not automatically inherit the new timing. Captions burned into the picture remain visible, but a separate SRT or VTT needs retiming. Mediaivo’s subtitle converter changes format, not speed-based cue timing.
Change speed in four steps
- Choose the useful interval. If only part of a recording is needed, use Trim Video first and keep the master.
- Upload to Change Video Speed. Select a supported factor from 0.5× to 2×.
- Process and play the output. Check a movement, a complete sentence if present, and the final frame.
- Check the duration. Use Metadata Viewer when an exact delivery length matters.
A speed example you can download
The original is a silent, four-second moving test chart. These are actual processor outputs. It demonstrates timing, not the quality of speech or music.
| File | Duration | Dimensions |
|---|---|---|
| Original | 4 seconds | 640 × 360 |
| 2× output | 2.083 seconds | 640 × 360 |
| 0.5× output | 7.958 seconds | 640 × 360 |
Download moving source · Download 2× output · Download 0.5× output
Ideal arithmetic gives 2 and 8 seconds. Encoded frame timing gives 2.083 and 7.958 seconds in these files. Check the actual end frame if your delivery requires precise timing.
Checked September 20, 2026 against Mediaivo’s processing functions. How we test · Download settings and measurements
Why slow motion may look choppy
A recording has a finite number of captured frames. Stretching those frames over more time cannot recover motion that the camera never captured. This tool does not synthesize new in-between motion with optical flow. Fast action captured at a low frame rate can look uneven at 0.5×.
Speed changes re-encode video. Return to the source for another version rather than slowing a sped-up copy. For the audio operation, see FFmpeg’s tempo filter.
Questions about speed and timing
Does 2× mean twice the duration?
No. It means twice the speed, so expected duration halves.
Will speeding up always halve the file size?
No. Duration decreases, but encoding bitrate and content affect size. Measure the output rather than assuming a fixed saving.
Can I change only one section’s speed?
The tool applies one speed to the uploaded clip. Trim out a section first; joining sections into a timeline requires a video editor.