Convert video to MP4

No. The conversion runs entirely in your browser. The file never leaves your device – there is no server that could see it. Once the page has loaded, the tool even works offline.

The video is encoded on your own device with FFmpeg compiled to WebAssembly, which is several times slower than a native program. Expect roughly one to three minutes per minute of 720p video on a laptop, more on a phone. Short clips are the sweet spot; for a two-hour film use a desktop program. The engine (about 32 MB) is downloaded once per visit.

H.264 video and AAC audio – the combination every phone, browser and TV plays. The quality setting maps to x264's CRF (20, 23 or 28): lower means better quality and a larger file. If your MOV or MKV already contains H.264, switch on “Copy video stream” – the file is only repackaged, which takes seconds and loses nothing.

Copying only works when the video stream is already H.264. WebM files contain VP8 or VP9, which MP4 players do not expect – switch the option off and let the video be re-encoded.

Files up to 300 MB are accepted, and a job is stopped after ten minutes. The whole file has to fit into the browser's memory, so clips of a few minutes work best. If processing stops, trim the clip first or lower the resolution.

We remove the file's global metadata, including the recording location an iPhone stores in MOV and MP4 files. Rotation information is applied, so the video keeps its orientation.