Реклама Google — средство выживания форумов :)
The MAN page for ffmpeg states the following use
ffmpeg -i inputfile.mp4 -vf "transpose=2" outputfile.mp4
The key being that you are not to use a degree variable, but a predefined setting variable from the MAN page.
0=90CounterCLockwise and Vertical Flip (default)
1=90Clockwise
2=90CounterClockwise
3=90Clockwise and Vertical Flip
ffmpeg -i 185532.mp4 -vf "transpose=2" -c:a copy -vcodec libx264 ship.mp4