when encoding to mpeg2 how can i remove the black blocks

[wizzy]

mpeg2 is good quality when the size is bigger so i have mpeg 2 file that in the bright part of the movie the picture is fine! but when it get darker i see blocks especialy in the black color...how can i fix it?

[Compound]

try a higher min bitrate .ther is no motion in these parts of the picture so the encoder uses less bitrate for these scenes therfore maximizing bitrate in motion scenes . or you can try a high cbr if disc space is not an issue.