How to use Change Video Speed
Speed changes duration and require audio time stretching. Extreme values can distort sound; phase one does not promise professional pitch preservation or optical-flow interpolation.
- Choose video and confirm original duration and audio tracks.
- Set a speed within the supported range.
- Preview audio and the estimated new duration.
- Encode and inspect sync, sound, motion, and ending.
Available controls
- Speed: 0.25×–4×
- Quality / CRF
- Audio bitrate; removing audio is not currently exposed
What it helps with
- Synchronized video and audio speed change
- Media is read and transcoded in this browser tab and is not uploaded to FreeTool to perform the task.
Compatibility and limits
- Extreme speed sounds and looks unnatural
- No AI or optical-flow frame interpolation
- Variable frame rates and complex audio can drift
Frequently asked questions
Will pitch change?
Time stretching is attempted within the supported range, but extreme settings do not promise professional pitch quality.
Why is slow motion choppy?
Slowing cannot create real frames and optical-flow interpolation is not included.
Is video uploaded?
Media is read and transcoded in this browser tab and is not uploaded to FreeTool to perform the task.