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Convert.mp4

Convert MP4 to WebM online

100% localFiles never leave your device — no upload, no account, no tracking.
About MP4 to WebM

Convert MP4 videos into WebM, the open format that streams efficiently in browsers. We re-encode to VP9 with ffmpeg.wasm at the quality you choose. VP9 encoding is thorough, so longer clips take a little time.

The transcode runs entirely in your browser. Your MP4 file never leaves your device.

How it works
  1. 01

    Add an MP4

    Drop your MP4 file onto the page or pick it from your device.

  2. 02

    Set quality

    Choose a CRF value for the output quality.

  3. 03

    Convert

    Click Convert to encode a WebM locally with ffmpeg.wasm.

  4. 04

    Download

    Save the WebM file.

Features
VP9 outputgreat for webadjustable quality
Frequently asked
How does the MP4 to WebM converter work?
Convert MP4 videos into WebM, the open format that streams efficiently in browsers. We re-encode to VP9 with ffmpeg.wasm at the quality you choose. VP9 encoding is thorough, so longer clips take a little time.
Are my files uploaded to a server?
No. Everything runs entirely in your browser using local JavaScript and WebAssembly. Your files never leave your device.
Does it cost anything or require an account?
No. The converter is free, needs no sign-up, and runs locally in your browser.
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