problems with codecs under vista x64

i noticed a problem with codecs under vista x64. they seem to work fine and i can open any movie but it is not the same quality. i'm using klm codec pack and a k-lite extension for 64bit. the picture is aparently the same as under xp but if you pay attention the picture is brightened with less contrast. practicly black isn't black anymore, it is grey and the colours are not real. the image is the same with any player: media player 11, media player clasic, bs player and vlc player. if anyone knows about this problem and fix it please tell me how.

Im not to sure of the problem or how to fix it but there is a quick fix. I was trying to play x264 mkv files and was having issues with media center because the player was 64bit and the codec was 32bit. Created massive problems but it was fixed by enableing ODC in Haali media splitter. Yeah so what the top left hand of the screen has the details on the image size fps and cpu load im over it. Expect to be your only option for fully fixing the problem untill developers/Media Center team at MS decide to get around to fixing the smaller stuff.