Also, a free option is using VLC (Video Lan Client) which is a free cross-platform video player that will play most formats. If you go to the "Window" menu and select "Extended Controls" you will get a panel with some video and audio options.
Under the Video filters tab I checked Transformation to see what would happen, and to my surprise it tilted the image counter-clickwise. Now I don't know what else you can do, for example if you can direct it which way to turn or tilt, but that's definitely something to play around with. Also under the Video menu there are other commands dealing with aspect-ratios and post-processing.