Quality issues

[Case]

I'm trying to encode an XviD from a VOB file. After 12.5 hours of patience, the results are a bit disappointing (see image). Weird artefacts at the bottom of the encoding. This is visible throughout the movie, sometimes smaller, but always there. I'd like to know what causes this, and how to avoid it.

Encoded using XviD (1) by mencoder, 730 kbps, 4 motion vectors (2), two-pass encoding (3), keyframe interval 240, QMin 2, QMax 9.
(1), (2) and (3) chosen because of their high quality properties.

Both VLC and QT Player show the odd colors and shapes at the bottom, which suggests it's not the player, I think?

Any suggestion welcome.

Encoded using XviD (1) by mencoder, 730 kbps, 4 motion vectors (2), two-pass encoding (3), keyframe interval 240, QMin 2, QMax 9.
(1), (2) and (3) chosen because of their high quality properties.

it seems that you are encoding to fit on one cd with an image width at about 640 px. With the chosen bitrate I would suggest you lower the width (like 528 px) or you go for two cds.

you may also try out the same scene with the DivX libavc preset but big picture and low bitrate mostly show artefacts.