Installing OpenCV with ffmpeg

As far as I can tell it is possible to install OpenCV without root access, but it's slightly more complicated. If you have root access then su now and ignore any of the instructions in italics.
The version I downloaded was opencv-0.9.7, so if you suddenly see numbers popping up, that's why. Substitute your version if using a later one.

OpenCV should now be installed. The next stage is to create a makefile to use with it.