Black screen on Aspect Ratio other than Original (1 Viewer)

[mpab]

I'm using RC4 on a laptop that's connected via S-Video to a TV. I've set it to start in the secondary screen. It works great except for a detail: most (but not all) videos appear as a black screen unless I set the Aspect Ratio in Original.
I could set the secondary screen to no lower than 800x600 for the TV, so that many videos that cannot be zoomed appear too small.
What puzzles me the most is that this kind of thing will happen in random video files of any given series, all with the same specs and the same codec (DivX or XVid).

I haven't been able to track down the cause. What can it be? The files play perfectly on VLC or any other media player.

Thanks


MediaPortal Version: RC4
MediaPortal Skin: Blue3
Windows Version: XP SP3
CPU Type: Mobile Athlon 64 3400+
HDD: 40gb
Memory: 768 DDR
Motherboard: Via K8T800
Video Card: Ati Radeon 9550
[Sound Card: SB Audigy 2 ZS Notebook
HTPC Case: Gateway 7422GX laptop
TV - HTPC Connection: S-Video

 

[Paranoid Delusion]

Not sure but i suspect some power saver in the laptop, could be cool'n'quiet limiting how well decoding is done, so the higher bitrate more demanding files will only display in there default aspect.

Could be totally wrong though, let's see if you have more ideas posted