Are you sure about the black-areas-blocking? I remember a long time ago, when I was younger and had time for this kind of tomfoolery, I noticed this exact issue

Are you sure about the black-areas-blocking? I remember a long time ago, when I was younger and had time for this kind of tomfoolery, I noticed this exact issue in my BlueRay backups. I figured I needed to up the bitrate, so I started testing, upping the bitrate over and over. Finally, I played the BlueRay and it was still there. This was an old-school, dual-layer, 100GB disc of one of the Harry Potter movies. Still saw the blocking in very dark gradients.