I just started experimenting with a helmet-mounted GoPro, and have discovered that I have a habit of tilting my head to the right so that all of my videos are tilted to the left. I've tried to correct this by shifting the mounting slightly, and pushing my helmet toward the left, but it seems that no matter what I do, there's a tilt to the video.

Is it possible to correct this when editing the video?

I have Windows Movie Maker 2012 and Avidemux 2.6 and while MM can flip the video 90* neither seems to be able to correct the tilt. Is this a capability of any video editing software?