(x264) Perhaps a ME range bug?

Hello there! New around here; this is my first post. I'm a hobbyist encoder, and I mostly do anime, but a decent amount of film too. Probably 70/30. Anyway, let me get a bit detailed here. Upon seeing the new 'K' anime PV, and it having a large size for it's length (244MB for 2.5mins), I decided to encode it myself. After fiddling with CRF and being surprised with how big x264 always ended up making the file, I said oh well, and I then decided to try out different ME ranges on the source since it was very actiony (plus I just love to test different values of things all the time :)), and I could get a feel for how much a higher ME range really helps. Anyway, here's the weird thing I ran into: x axis is ME range, y axis is resulting file in bytes. As you can see, the 24 is even bigger than 16. I didn't see how that could be possible in any way, and at first I shrugged it off, but then I decided to post about it. Maybe to possibly find a bug, or learn something in the process :) Encoder used is JEEB's 64bit 10bit output version r2216+698 b3c1019 I would try an encode with the one from x264.nl, but I believe I would have to use something other than AQ3, though that might not necessarily be a bad thing, since if the results came out "more correctly", perhaps it could be a bug with AQ3 instead. But first things first I suppose. And speaking of settings, if you would like to see settings used I can post that too of course. Glad to be here! Long time lurker.

@mandarinka Check your calculator. The difference is not 20%. That would be a bit too much, really. ME64/ME24 : (90'200'000)/(92'400'000) =~ 0.976, i.e. the diff is 2.4%. ME32/ME24 : (91'500'000)/(92'400'000) =~ 0.9902, i.e. a diff of 1%.

Well this is interesting, I didn't expect such replies and in such a matter of time.. but it seems like I wasn't clear enough. Either that or perhaps Muler is being overly helpful and I'm taking it as him not understanding fully. Let me try again, and I'm sorry if your answer ends up being the same, I guess I have some learning to do :o Anyway, it's the same source file for all the encodes, exactly the same settings, same CRF etc., with the only change being the ME range. It was just a little test I was conducting since it seemed like a source that would make the differing ME ranges really stick out. The only weird thing was that at 24, it somehow produced a file larger than ME range 16, when all other settings were exactly the same. Now, I could just drop the whole thing, and say to myself there could be some complicated reason for why the file came out bigger.. perhaps it was finding more things to try to encode as a vector but not finding its paths as often, creating a larger file in the end. Or that could be a bunch of crap, because my only basis is logical thought rather than studying of the specifics of x264 :) Other than that though it just seemed impossible. Still, I wanted to ask about it, since all the steps beyond 24 were exactly what I would expect. But for some reason 24 just... wasn't, heh (except also maybe 32 to 40 being not as much as you would expect, but of course there could be many reasons for that based on the source material.) Anyway 24 coming out a bit bigger was just weird when given precisely the same settings. Either way I appreciate the input, this stuff interests me greatly.

Don't test this kind of thing with CRF. Use 1 or 2 pass VBR / CBR to test.