Colors "washed out" in Windows 7

[realnc]

This is probably an mplayer issue rather than an smplayer one, but maybe someone knows what's causing this. Under Windows 7, videos look "washed out". The main issue seems to be that black is displayed as a rather bright gray. This happens with the regular mplayer as well as the mplayer2 package of smplayer (0.8.5). This doesn't seem to be fixable using the equalizer. If I lower brightness, the video gets too dark.

This is on NVidia hardware, in case it matters.