Re-encode MP4, MOV, MKV and more with H.264 at the quality you choose — typically 50–80% smaller, with no upload, no watermark and no size paywall.
MP4 · MOV · WebM · MKV · AVI · GIF
Cameras encode in real time on a battery budget, so they favour speed over efficiency and use generous bitrates. Re-encoding the same footage offline, with a slower and smarter encoder, routinely halves the file with no visible difference.
Resolution is the blunt instrument: 1080p → 720p removes more than half the pixels and is invisible in a phone-sized player. CRF is the fine adjustment: it lets the encoder spend bits where the eye notices and save them where it does not. Use resolution first if the target is messaging or email, CRF alone if the video must stay full-size.
Email attachments generally cap around 25 MB; most chat apps around 100 MB. For a one-minute 1080p clip, 720p at CRF 28 usually lands well under both without looking processed.
For web embedding, WebM with VP9 is smaller again at the same quality. If only the sound matters, extract the audio and skip the video entirely.
Constant Rate Factor tells the encoder how much quality to preserve rather than fixing a bitrate. 18 is visually lossless, 23 is the encoder default, 28 is a good size/quality compromise, and 32+ is visibly soft. Each step of 6 roughly halves or doubles the file.
Phone recordings and screen captures typically shrink by 50–80% at CRF 28 with no obvious quality loss, because their original encoders optimise for speed rather than size. Already-compressed downloads gain much less.
Often, yes. Halving the width removes three quarters of the pixels — a bigger saving than several CRF steps, and usually less noticeable if the video will be watched in a small player.
No imposed limit, but processing happens in memory. A few hundred megabytes is comfortable on a typical laptop; larger files are better handled by a desktop encoder.
The WebAssembly encoder cannot use your hardware video encoder, so it does the work on the CPU inside the tab. Long 4K footage can take much longer and may exhaust the tab’s memory.