Compress video

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.

It is x264's CRF: 18 is visually lossless, 23 the usual default, 28 noticeably smaller with slight softening, 35 for tiny previews. Each step of 6 roughly halves the file size. For 4K sources, reducing the width to 1280 pixels saves more than any CRF change.

MP4 with H.264 and AAC is the smallest widely playable combination. If you need WebM, use the WebM converter, which offers VP8 and VP9.

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.