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Video Speed Changer

Adjust video playback speed to create fast-forward or slow-motion effects with synchronized audio speed adjustment.

Free to use, no watermarks, runs in your browser—nothing uploads to our servers

Source file

Files are processed locally in your browser using WebAssembly.

Saved FFmpeg presets (stored locally)

Saved presets

Preset name

Speed Multiplier

0.5 = half speed, 1.0 = normal, 2.0 = double speed

Jump to helper sections

What speed values can I use?

Use values between 0.5 (half speed/slow motion) and 4.0 (4x speed). Values below 1.0 slow down, above 1.0 speed up. Common values: 0.5 (slow), 1.5 (fast), 2.0 (double speed).

Does changing speed affect audio?

Yes, both video and audio are adjusted proportionally. The audio pitch will also change with the speed. For separate control, use audio editing tools.

Can I create smooth slow motion?

This tool slows down existing frames. For smooth slow motion from regular footage, you'll need frame interpolation which requires special processing.

Report a bug

If this tool misbehaves, share a quick summary so we can investigate. We include the tool URL automatically—no need to copy and paste.