@johnmeyer
the processed sample here,
https://mega.nz/#!jx8TUAhB!VfsoBw2LR...0Fls1IH4RjICYY
random stuff:
1. scaled to 1920x1080 cuz block matching at 4k is way too heavy to my crappy i7-4790k
2. ditched chroma planes, I simply don't care much about chroma and the artifacts show mostly on luma plane anyways.
3. losslessly compressed with avc lossless
Does it look okay to you now?
the solution is a bit complex, so, I'm waiting for your reply.
I'll go on explaining if the answer is "yeah"