This should give you the break down of what your wanting to do, you may need a couple add on's for WMC to have all the tweaks needed
http://www.pcbuyerbeware.co.uk/How-to-improve-windows-media-center-in-windows-vista-and-windows-7.htm
How to improve the Windows Media Center's video picture quality
The picture quality of many downloaded videos isn't very good, but you
can correct this. When playing a DivX video, switch Media Center out
of Media Only mode by using your mouse to put the application into
windowed mode (click the middle icon when you move the mouse to the
top right). You should see two new icons in the Notification Area
(bottom left corner): a blue ffdshow audio decoder and a red ffdshow
video decoder. Double-click on the audio icon first to set the correct
audio settings. Place a check mark in the Mixer box and then click
Mixer. Select the Output speakers configuration from the drop-down
menu. For most PCs with surround sound, this should be 3/0/2 for five
channels, but for 7.1 speakers select 3/2/2. If you have
surround-sound speakers, also place a check mark in the LFE box to
send the subwoofer its own signal. Next, click Dolby decoder and
choose Apply Dolby Pro Logic II decoding to all stereo sources. This
should upsample stereo soundtracks to use all of your speakers. Click
OK.
Now double-click on the video icon. For every setting we mention here,
make sure the Process whole image option is selected. Place a check
mark in the Deinterlacing box and choose Cubic interpolation from the
drop-down menu. This will deinterlace TV programmes so that they match
your TV's progressive mode. Use the mouse to place a check mark in
Postprocessing, and another in Picture Processing and adjust the
sliders until you're satisfied with the picture's colour, brightness
and contrast.
Because downloaded video can look disagreeable, place a check mark in
the Blur&NR (blur and noise reduction) box. Setting Soften to 40 or
less and Gradual denoise to 40 or less should help to reduce noise and
produce a better image. The detail in a video can be improved by
placing a check mark in the Sharpen box. Select Unsharp Mask and
adjust the Strength bar until you're satisfied with it (25 should be
good enough). To make sure the picture look as good as possible on a
TV, you can force ffdshow to upscale video so that its screen
resolution matches that of your TV. Place a check mark in Resize &
aspect. Select Specify horizontal and vertical size, and enter the
size of your display in the box below, such as 1,920x1,080 for 1080p
TVs. The video maintains its aspect ratio by default, so old TV shows
will have black bars down the side of the picture. If you don't want
this, select No aspect ratio correction, click Apply and the image
will fill the screen. You can now maximise Media Center and use it as
normal.