I ported the documentation to RDoc. RDoc generates a nice overview of the classes and functions. If I find some time I may customize it a bit, but for the moment it is sufficient.
I also found a bug in Hornetseye::XineInput. I realised that Xine does 64-bit alignment of all planes when it returns frames in YV12-colourspace (which is the most common case). Now videos were the width modulo 8 is not zero will not appear sheared any more.