About this tool
Reframe a landscape recording for vertical platforms, or square it up for a feed. The crop is centred and cut to the exact aspect ratio, then re-encoded to H.264 MP4 with the audio untouched. Expect roughly real-time processing, since cropping requires re-encoding.
Everything happens inside your browser. Your file is never uploaded to a server: the conversion runs on your own device using WebAssembly, and the result is downloaded straight from memory. Close the tab and nothing is left behind.
How to use it
- Drop your MP4 file into the box above, or click to browse. Nothing is uploaded.
- Adjust the options if you want; the defaults suit most files.
- Click the button and wait a moment.
- Download the result.
Frequently asked questions
Can I choose which part to keep?
The crop is centred for now. Position control is planned.
Does cropping reduce quality?
The video is re-encoded at a high quality setting; for typical phone footage the difference is not visible.
Is this really free?
Yes. The site is supported by ads, and there are no limits on how many files you convert.
Are my files uploaded anywhere?
No. The converter runs entirely in your browser. Files stay on your device, which also makes it faster than upload-based converters for anything larger than a few megabytes.
Is there a file size limit?
The only limit is your device's memory. Images and audio of any normal size are fine; for video, files under about 500 MB work well on most laptops and phones.
Which browsers are supported?
Current versions of Chrome, Edge, Firefox, and Safari on desktop and mobile. Very old browsers without WebAssembly support will not work.