Video Compressor

A video compressor re-encodes a file so it takes up less space. The picture and the sound are decoded and written again at a lower bitrate, which throws away detail a viewer is unlikely to miss and keeps the rest. That is the whole trick, and it is why a 300 MB phone clip can become a 40 MB file that still looks fine on a laptop: most of what a camera records is more information than the footage needs.

This one runs entirely in your browser. The file is read from your disk into the page, encoded there, and handed back as a download. It is never uploaded, there is no queue, and no copy waits on a server for a retention policy to delete it, because none was ever made. That matters more for video than for most file types: a clip is usually the largest and most personal thing anyone compresses, and the normal arrangement for a free online compressor is that you hand a stranger your footage in exchange for a link. The work here is done by ffmpeg compiled to WebAssembly, the same engine most desktop encoders use underneath, running in the tab instead of on a machine you do not control.

There are two settings that matter and the page offers only those. The first is how hard to compress, expressed as three levels rather than a slider: a constant-rate factor of 23 is near enough visually lossless, 28 is the ordinary "make it smaller" setting, and 33 is where artefacts begin to show on detailed footage. The second is resolution. Dropping a 4K clip to 1080p removes three quarters of the pixels before the encoder even starts, which is almost always a bigger saving than any quality setting, and nobody watching on a phone will notice. Audio can be dropped entirely when the sound was never the point, as with a screen recording.

Two output formats are offered because they are genuinely different trades. MP4 with H.264 plays on everything - every phone, every browser, every chat app, every CMS upload field. WebM with VP9 lands roughly a quarter smaller at the same visible quality and takes noticeably longer to encode in a browser. If the file is going to someone else, send MP4. If it is going on your own site, WebM is usually the better file.

The limits are the browser's rather than a paywall's. The whole file is read into the tab, so the page accepts up to 500 MB and a single pass is capped at thirty minutes. Within those numbers a laptop is comfortable. Past them, a desktop encoder is both faster and more reliable, and we would rather say so than hand you a tab that runs out of memory halfway through. It is free, with no account, no watermark and no size tier to buy.