Some videos, when played in QT Player, don't display properly. The video plays on 2 halves of the screen: one image on the left half, a second image on the right half. Images are approximately identical; they seem to be alternate lines of video. For example, it seems the left half image is made up of the odd scan lines, and the right one of even. (To my eye they also seem to be offset by one video line. It looks like each image is missing every other scan line, and if they were overlapped, they would create one image, I think.)

The videos that don't play nicely are, according to VLC:
Video A: msmpeg4, yuv420p, 608x304, 29.97 fps Div3
Video B: mpeg4, yuv420p, 608x256, 25.00 fps XviD
Video C: mpeg4, yuv420p, 640x480, 25.00 fps XviD
Video D: mpeg4, yuv420p, 588x244, 25.00 fps XviD

The only video I can get to play in QTP is of this format:
Video X: mpeg4, yuv420p, 576x240, 25.00 fps Mpga

All these videos play fine in other players (MPlayer, VLC).

I always presume I'm missing something, either some knowledge or a s/w component. What is it?

Thanks,
JJ

Mac OS X 10.3.9; QT 7.1.3
QT folder contains:
DivX Decoder.component v6.4.0
3ivx D4 4.5.1 for OSX
XviD_Codec v0.5.1.component