Change the speed of a video
Change the speed of a video from 0.25× to 4× and save it as MP4. The pitch of the sound stays the same. The video is processed only on this device.
- Free
- No upload
- No sign-up
- Works offline
How to use
Press "Choose a video" and pick one video.
Choose the speed and the sound, then press "Change speed".
Press "Save" to save the video at its new speed (such as speed-2x.mp4).
Questions
Is my video sent anywhere?
No. Reading the video and changing its speed both happen on your device. Nothing is sent out after you choose a video.
Does the quality get worse?
Usually not. The picture is not made again: only the time each frame is shown changes. But at speeds that would give more than 120 frames a second (3× or 4× of a 60 frames a second video, for example), frames are left out and the picture is made again, so the quality changes a little. The tool says so before making.
Does the pitch of the sound change?
With "Same pitch", the pitch stays the same and only the speed changes. Very fast or very slow speeds can make voices sound a little different. With "No sound", the video has no sound.
Why can some speeds not be chosen?
Speeds that would give fewer than 10 frames a second cannot be chosen, because the movement would not look smooth (0.25× of a 30 frames a second video, for example). Speeds that need frames left out and the picture made again can be chosen only in browsers that can do that. The tool says why for each video you choose.
Does the location or other hidden information stay?
The location, the date it was taken and the device do not stay. The new video has only the picture and the sound: the information that phones put into videos is not included, and the creation date of the new video is left empty. Information that cameras and other devices write inside the picture data is taken out too. Captions stored as separate data are not included. When the picture is not made again, captions and time information written inside the picture data stay.
What is the saved file called?
A name with the speed in it, such as "speed-2x.mp4", because the original file name often includes the date the video was taken.
Can I use it on a phone?
Yes. Inside apps such as LINE, saving may not work. If so, open the page again in Safari or Chrome. Keeping the pitch needs a browser that can make AAC sound; other browsers offer "No sound" only.
Limits
- MP4 and MOV videos (H.264 or HEVC picture) up to 2 GB can be used. WebM, AVI, MKV and other formats cannot.
- The speeds are 0.25×, 0.5×, 0.75×, 1.25×, 1.5×, 2×, 3× and 4×. Speeds that would give fewer than 10 frames a second cannot be chosen.
- At speeds that would give more than 120 frames a second, frames are left out and the picture is made again (videos of up to 10 minutes). The files made again are up to 500 MB on iPhone and iPad, 1 GB on Android, and 4 GB on computers and other devices (1 MB is 1,000,000 bytes).
- The pitch can be kept for videos of up to 10 minutes, in browsers that can make AAC sound. Other browsers offer "No sound" only.
- One picture track and one sound track are kept. Captions stored as separate data are not included.
- Bigger and longer videos take longer. Please keep this screen open while the tool works.
- We cannot protect against things in your own environment, such as browser extensions.
- The work is done on this device, so how long it takes depends on how powerful the device is. On an older phone, it can take several times as long as on a computer.