Video to MP4
Convert WebM, MOV and other video to real H.264 MP4 with WebCodecs — on your device.
About this tool
Drop a WebM, MOV or any video your browser plays; pick a size; get an MP4 that PowerPoint, iMovie, WhatsApp and every player accept. Encoding uses the browser's built-in H.264 and AAC encoders through WebCodecs, on your device.
Why MP4, why now it's possible, and where it isn't
MP4 with H.264 video and AAC audio is the one format everything opens, and until recently browsers could decode it but not write it — which is why screen recorders produce WebM and why “convert to MP4” has meant uploading to a server. WebCodecs changed that: Chrome, Edge and recent Safari expose the operating system's hardware encoders to web pages, and this tool feeds them frame by frame (30 per second, pulled by seeking, so a minute of 720p usually takes well under a minute), muxes the result into a standards-compliant MP4 with the open-source mp4-muxer, and encodes the soundtrack to AAC. Honest limits, stated on the page as they happen: Firefox and older browsers lack the encoder, so the tool tells you rather than failing silently; the video is re-encoded at a fixed frame rate rather than copied; and where the browser has no AAC encoder the MP4 is written silent with a warning. For a quick share where WebM is fine, the compressor and the trimmer are faster; video to GIF makes the silent loop.
Frequently asked questions
Which browsers can convert to MP4?
Chrome and Edge on a computer or Android, and Safari 17 or newer. Firefox can't write MP4 yet; the page says so instead of failing. Encoding works best on a laptop or desktop.
Is it real MP4 (H.264)?
Yes — H.264 video (avc1) with AAC audio in a standard MP4 container with the index at the front, so it plays in QuickTime, Windows, phones and every editor.
How long does it take?
Usually faster than real time: a one-minute 720p clip converts in 20–40 seconds on a laptop. Larger sizes and older machines take longer; the bar shows progress.
Is the video uploaded?
No — decoding, encoding and muxing all run in your browser using its own codecs. Nothing leaves your device.