Hello :)
I made three versions of a slitscan patch: A horizontal, a vertical, and a wide vertical Slitscan.
For me it runs well if the frame buffer size is ~ <= 200.
Only if the loop starts again there is a short delay (which seems to have to do with the ofVideoPlayer - because of that I rendered a video with 30 seconds of the loop for using it with Ofelia)...
I still wonder if and how I can optimize the patch.
Next thing to discover would be optical flow ;)

Here are the patches: ofelia_slitscan_and_muybridge.zip

With the Muybridge patch I had the idea tho show the whole sequence of the riding horse sequence at once and in motion: