> On 22 Dec 2018, at 12:11, Tomas Härdin <tjop...@acc.umu.se> wrote: > > tor 2018-12-20 klockan 17:46 +0000 skrev Matthew Fearnley: >>>> On Thu, 20 Dec 2018 at 16:30, Tomas Härdin <tjop...@acc.umu.se> wrote: >>> >>> I have a feeling this could be sped up further by just doing *xored = >>> histogram[0] == ZMBV_BLOCK*ZMBV_BLOCK after the loops, if [PATCH 3/4] >>> is applied before this. Computing both histogram and xored in the loop >>> seems pointless. >>> >> >> You're right, that speedup didn't occur to me. It makes the logic a bit >> more tenuous, but it would be more efficient. > > Eh, I wouldn't really call "we have xored data to output if and only if > number of zeroes < number of pixel" fairly easy to grasp. A comment > might be good tho Agreed. Just have to get the patch order sorted out now somehow. >> Note that bw,bh aren't guaranteed to equal ZMBV_BLOCK, so `histogram[0] == >> bw*bh` would have to be used to guard against those (literal) edge cases. > > Right, yes. But if we have block sizes other than ZMBV_BLOCK^2 then we > need score tables for those sizes too. I’ve thought about that a bit. I wondered if it would be worth it given: - the extra code, memory and logic needed - it would only improve the edge blocks - the existing score table isn’t catastrophically bad for short blocks, and would still favour blocks with more common pixels.
It would be better from a correctness perspective though, and effects on running time should be negligible. I can work on a patch, see how it looks. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
