English Amiga Board - View Single Post

robinsonb5 · 14 July 2020, 12:37

I've been tinkering with this a little this morning - I've picked a couple of busy-looking frames and done a horizontal edge-detect to find the boundaries for blitter fill.

I'm assuming here that we'd want to use a separate buffer for even and odd frames, and would blitter-fill into separate destination buffers, leaving the source unchanged. We can avoid clearing buffers by just overwriting what's changed since two frames previously.

So taking this random pair of frames, two frames apart in the animation, and finding the differences between them, the second one can be encoded as a series of 1637 word writes over the top of the first one. In a horribly inefficient text-based format, in which the first number is the number of words to skip and the second is the literal word to be written, the second frame looks like this:

Code:

Once encoded more efficiently, and converted to binary, that strikes me as something that will compress pretty well.