vf filter 'rotate' also flips the image vertically

[yuri@…]

"-vf-add rotate" rotates the video CW, but also flips it, so I have to add "-vf-add mirror" to achieve pure rotation by 90 degrees.

mplayer-1.1.r20130308

[reimar]

-vf rotate rotates CCW, not CW. I think you want -vf rotate=3
Also, -vf flip,rotate would be much more efficient than -vf rotate,mirror

[yuri@…]

testcase video

[yuri@…]

I am attaching the short video like this. See it with 'mplayer -vf rotate video.mp4' and you will see that it is flipped.

[reimar]

Ok, I admit the default is a bit questionable (and I gave the wrong example), but to not flip use -vf rotate=1 (CCW) or -vf rotate=2 (CW)

[yuri@…]

My main problem is why flip is included into rotate? I don't think this is reasonable.

-vf rotate does CW+flip, but -vf rotate=1 just does CW. This isn't intuitive. rotate=1 is what I originally wanted.

[reimar]

My main problem is why flip is included into rotate?

Because it's cheap and efficient to do them together (vastly more than doing them separately, essentially free).
Also rotating 270 degress is flip+rotate90+flip, thus the filter already implements the flips (for efficiency it actually does not implement rotate at all, it only implements transpose - which when combined with exactly one flip makes a rotate).
Doesn't make it intuitive but entirely reasonable from an implementation point. Probably the default should at least be one of the cases without flip though, but I don't think it is a good idea to change the numbering and possibly break everyone's scripts.