A quick note to any users (According to Webalizer people other than myself have downloaded it, so I have to presume that I actually have some now!):

I noticed a bug in the HBP stereo algorithm whilst trying to create a demo video of it the other day. It crashes if given input that is masked. I'll have a look at it this weekend some time, I doubt its hard to fix. In the mean time, either crop away masked areas (As typically got from rectified images.) or revert to the older HDP algorithm.