You_Too said:
I opened the blu-ray in avspmod using a script and there it's smooth. So it's MPC's fault.
I see, glad you found the culprit. I usually use VLC but I will check how reds look on my player when I am able to and report back.
Edit: I checked a few films in MPC and I cannot see this problem with reds, I don't own the blu-ray but I checked the '04 DVD and the blockiness isn't there so I have no idea what's causing it with your player.