Rotate a video

How to use it#

1. Drop a video onto the box above, or click it to choose one.
2. Pick 90° right (clockwise), 180°, or 90° left (anticlockwise). The video is turned straight away.
3. Check it in the preview, then download it.

How a video is turned without re-encoding#

Most phones, iPhones included, record the picture the same way round whichever way up they are, and store a note of how the phone was held: a rotation tag, which players read to show the video upright. That is why a video filmed in portrait plays in portrait. Turning an MP4 or a MOV here changes that tag and copies the picture as it was, so nothing is decoded, the quality is identical, and a long video takes no longer than a short one.

A player that shows phone videos the right way up is reading that tag, so it shows the turned video the right way up too, as phones, browsers, and QuickTime do. Most editing apps read it as well, though an older program may ignore it and show the picture as it was recorded. The turn is written into the file, so it stays when the video is sent or opened somewhere else, where a player's rotate button only turns it while it plays. The date, place, and phone model a video records are kept.

WebM and MKV files#

A WebM or an MKV has no rotation tag that players can be relied on to read, so its picture is turned frame by frame and encoded again, at a high quality and never at more than the bitrate of the original. That takes much longer than changing a tag, and the page shows that the video is being encoded again. The sound is copied as it was.

Which way to turn it#

Pick the turn that brings the top of the picture to the top: 90° right if the top is on the left, 90° left if it is on the right, and 180° if the video is upside down. The preview shows the result as soon as it is made, so a wrong guess costs a second and another press.