Is it possible to rotate (90 degrees) already uploaded video's on YouTube?
Can I rotate already uploaded video's on YouTube?
youtube;video editing
YouTube's video editing has changed from how it was back in 2011 when this answer was first posted. You can now rotate your videos by going to the Video Manager page and choosing the Enhancements option from the Edit menu next to your uploaded video. You can also get there by clicking the Enhancements option below the player when viewing your video: On the enhancements page, the rotate options are on the bottom, next to the Trim button: