I currently have a fresh install of Windows 7 X86 RTM.  I have added my movies to interface my MKV movie library.  For playback I have installed the Divx Tech Preview MKV Playback on Windows 7 found here, http://labs.divx.com/mkvwin7preview  For Audio I have installed the AC3 Filter from here, http://ac3filter.net/projects/ac3filter

 Video card is a G-Force 9600 GT using the latest Nvidia Drivers

Once I associate MKV files with Media player Media player plays them perfectly, both Video and Audio.  The Quality is exceptional and very simlar to what I was getting in Vista if not better.

 When I play the same movie files, the exact same scenes the Video Quality from Media center seems to have to much brightness during dark scenes, making the video full of artifacts, etc.

 This is especially obvoius from Concert MKV files since often Concerts have a lot of dark scenes and light shows.  These same scenes within Media player look flawless.

 So my questions, Does Media Center and Player not use the same Playback engine and codecs?  Since I have not switched any of the codecs using some of the methods floating around and everything is at default I figured they would have an identical picture.

 Looking around it seems as though this issue occured with Vista as well, http://www.driverheaven.net/mobility-radeon-drivers-support/153038-strange-black-artifacts-all-over-white-areas-vista-media-center-video-playback.html

 My goal is to get Media center to achieve the same picture or better that Media player produces.  Maybe someone has some recomendations on what is occuring here or an optimal solution for achieving a proper picture when playing MKV within media center.  Any help with this is greatly appreciated.

Okay, so I tried some more tests, Installed FFDShow, Hali, and forced these as the codecs, confirmed they are indeed being used and tested Media player first.  As expected the MKV files looked perfect and once again when Played from media center any dark scene is fully of artifacts and to much white light.

I have tried changing the settings within Nvidia Control panel using Nvidia settings for Video, etc.  Even tried reinstalling Windows 7 and started from scratch, same results, after a few google searches I am seeing this issues all over the place with Vista, same problem explained here.

 It almost seems Media center is using a completly seperate set of settings for Video Quality, example if I tell Nvidia control panel to use Nvidia settings and rudce the brightness this has no effect however it has an instant effect within Media player.

 I find it hard to believe everyone is just playing MKV's from Media center and accepting the results I am seeing.  Has anyone else noticed this or even better there must be a solution.

There's another thread on video quality here:

http://thegreenbutton.com/forums/p/59322/352966.aspx#352966

Starting about where the link picks it up is a discussion about how Media Player looks fine and Media Center looks washed out and a registry change is given to change the output range of media center.

See if it helps your situation.

You might want to read the entire thread if you're adventuresome.

There's also an nvidia control panel setting for Dynamic Range, Limited or Full. Setting it to full should make your blacks blacker im MCE, but then it would screw up MP. 

But these settings should be affecting all video, not just MKVs.

I should say, I've experienced none of these problems when playing MKVs. I didnt install any extra codecs but did install the Haali Splitter and everything plays fine with my 8500GT/