Background big pixels

[Diveflo]

Hi ;)

I got a little problem...I'm encoding 720p (high profile) mkvs to mp4s for my AppleTV. But everytime I reencode the videos, where there is some one-colored background there are extremly big pixels. That's just disgusting :( The picture looks beautiful everywhere else, but when there is a background in one color, there are just big disgusting pixels.
I always chose a bitrate near or exact to the source.

I tried Ripbot, MeGuie, Nero recode...everything :(

[nm]

You mean blocking and banding. This has been discussed to death already, so use search. To overcome it, try x264 patched with Dark Shikari's VAQ (IIRC, MeGUI has it set on by default if you have the latest, updated version).

[Atak_Snajpera]

Next time show some screenshots