How can I rotate a video by a few degrees? I've taken a fairly tilted video and want to rotate it to be level, how can I do this?  I'm open to any third-party apps but purely apple solutions are better.  I have FCPX, but I don't know if I can use that.
Import the video in FCPX (don't worry about creating optimised/proxy media, etc).
Create a project and add the clip.
Use Transform (⇧T) to rotate (and scale) the clip as appropriate.
Export.