Full screen "interlacing"

[ZoZo2]

I'm using BSPlayer 1.02 (but it happened with previous releases) with ffdshow, and when I go full screen on an XviD video, horizontal lines appear, as if the video was interlaced (but it's not). I'm using overlay mode 1, which IMO provides the best quality. With VMR-9 and overlay mode 2 (stutters a bit), this does not happen.

I have a GeForce 6800 GT and also tried with a GeForce Ti4200, and tried different drivers, including the latest ones, but the problem is always there. Also, I had formatted my drive and reinstalled everything, and it happened again! My monitor is a Philips LCD using DVI connection.

Zoom Player and WMP don't have this problem.

Is this a known problem? Is there a fix?