ALL VIDEO TOOLS23
Rotate Video
Rotate Video Online — Free, No Re-Encode
Turn a sideways clip upright by rewriting its rotation flag — no re-encoding.
About Rotate Video
A video shot sideways is almost never sideways in the file. MP4 and MOV both store a display matrix — a small piece of container metadata that tells a player how to turn the frames before showing them — and a phone that was held the wrong way simply writes the wrong value into it. Fixing that means rewriting one field, not re-encoding a single frame, and the difference is not subtle: on a ten-second 720p clip the flag rewrite measured six milliseconds against roughly seven and a half seconds for the equivalent re-encode, and the flag rewrite is lossless while the re-encode is not. The honest caveat is that a rotation flag is a request, not a guarantee. Most modern players — QuickTime, VLC, iOS, Android, current browsers — read it and rotate accordingly; some editors, some older players and some upload pipelines ignore it and will show the clip exactly as it was shot. The stored frame dimensions do not swap either — a 1920×1080 file rotated 90 degrees still reports 1920×1080 with a flag attached. Preview the result before you rely on it. FFmpeg runs as WebAssembly in your browser.
Questions
Does this re-encode the video?
No — and that is the whole point. MP4 and MOV store a display matrix telling players how to turn the frames, and this rewrites that one field. Measured on a ten-second 720p clip: 6 milliseconds for the flag rewrite against 7,579 milliseconds to re-encode the same rotation, and the flag rewrite loses nothing.
Will every player show it rotated?
No, and it would be dishonest to promise otherwise. A rotation flag is a request. Most modern players — QuickTime, VLC, iOS, Android, current browsers — read it and rotate accordingly; some editors, some older players and some upload pipelines ignore it and show the clip exactly as it was shot. Preview the result before you rely on it.
Why do the dimensions still show the original size?
Because the frames themselves were never touched. A 1920×1080 clip rotated 90 degrees still reports 1920×1080, with a rotation flag attached that a player is expected to apply. Anything that ignores the flag sees the original, unrotated frame.
When should I re-encode instead?
When the destination is known to ignore rotation metadata — some editing suites and some upload pipelines do. A re-encode bakes the rotation into the pixels so nothing downstream can disagree, at the cost of time and a generation of quality. For everyday playback the flag rewrite is the better trade by a wide margin.
Which formats can I rotate?
MP4, MOV and M4V. The rotation flag lives in the display matrix that ISO base media containers define, so those three are where it can be written reliably — AVI has no equivalent field at all.
Is my file uploaded to a server?
No. Transmute processes everything locally in your browser using JavaScript and WebAssembly. Your files never leave your device — there is no server, no upload, no cloud processing.