Rotate Video Online
Turn sideways phone footage upright or flip your clip for social posts. Processed locally in your browser - no upload, no watermark.
A phone video can look correct in your camera roll but sideways in another app because the file may store a rotation flag instead of storing upright pixels. When a player or uploader respects that flag, your clip looks fine. When it ignores the flag, your video appears rotated even though the recording itself is not broken.
GrepCut gives you two fixes for that problem. Social-ready mode physically rotates the frames and clears the rotation flag, which is the safer choice before you post. Fast remux keeps the original video stream and updates the rotation metadata, which is faster but depends on the next app reading the flag correctly.
Fast remux is useful when you want a quick local fix and you know the next player reads MP4 rotation metadata. It can be the right choice for previewing, archiving, or sending a file to an app that already handles rotation flags correctly.
Social-ready is better when the clip will be uploaded, compressed again, or opened across different devices. By writing upright pixels into the MP4, you remove the guesswork. Your export may take longer, but the file is easier for social platforms and basic players to display correctly.
Can you rotate a video without uploading it?
Yes. GrepCut runs the rotation process in your browser, so your file stays on your device instead of being uploaded to a server.
Why does your MP4 look sideways in one app but correct in another?
Your MP4 may contain rotation metadata. Some players read that instruction and rotate the video during playback, while other apps ignore it. Use **Social-ready** mode when you want the exported MP4 to contain upright pixels instead of relying on metadata.
Should you use Social-ready or Fast remux?
Use **Social-ready** when you plan to post the clip online or send it to an app that may ignore rotation flags. Use **Fast remux** when you want the fastest export and the next player is likely to honor MP4 rotation metadata.
Will rotating your video reduce quality?
Fast remux keeps the original video stream unchanged, so the video stream stays identical. Social-ready mode re-encodes to H.264 so the rotation is baked into the pixels, which is more reliable for posting but takes longer.
What video formats can you rotate?
You can add MP4, MOV, WebM, MKV, M4V, and most common video formats. GrepCut exports the rotated result as MP4.
Will your audio stay in sync after rotation?
Yes. Rotation does not change playback speed. Audio is copied losslessly when it is already AAC, or re-encoded to AAC for broad MP4 compatibility.
Can you rotate by a custom angle like 12°?
No. This tool is built for right-angle fixes: 90° clockwise, 180°, and 90° counter-clockwise. For sideways phone footage, those are usually the corrections you need.
Why does GrepCut need a modern browser?
Social-ready export depends on browser video processing features such as WebCodecs. If your browser does not support the required APIs, try an up-to-date Chromium-based browser.