Media Player Classic Home Cinema 64Bit is a media player with builtin codecs. MediaCenter on an x64 OS is also a 64bit media player. MediaCenter uses Windows Media Foundation and fallsback to using directshow codecs when WMF fails to decode the file selected.
MediaCenter cannot access the codecs within the MPC-HC player. They are for exclusive use by that player. If you want MediaCenter to play your content you'll need to install directshow codecs capable of decoding the content.
I normally would suggest my own codecs, Shark007's FREE Codec solutions.
but am afraid that build 7100 has so many decoding problems to begin with, I would not want to deal with all the issues you will come up against.
If you do try my software, install both the Win7codecs and the x64 Components addon, then, once installed, you have to open the x64 Settings Application to the MP4~MPG TAB and select Gabest as the splitter to be able to playback ripped Blueray content in MediaCenter. This isnt a default setting because it interferes with streaming online mpeg2 content.