I have filmed a video with my phone horizontally, but at a certain point I turned my phone vertically while recording. That was not very smart from me, because now when I play the video back the picture is 90 degrees turned. At a later point in the video, I turn my phone back horizontally again and the picture is good again.
I was wondering if it is possible to turn this picture gradually back with 90 degrees in that particular part of the video where i turn my phone vertically. Is this very difficult to do or easy?