After updating to the latest Nvidia drivers my picture quality took a turn for the worse which resulted in some research and re-calibration. Listed below are my current settings and the reasons why.
1) If you're using a PC, then be sure to set you C10/638 to use the "input label" of "PC" for the PC input. Doing this will result in your C10/638 treating the signal as 0-255. This is important since I've noticed if you calibrate the C10/638 using the other input labels that it results in some additional black crush - where blacks fall off too soon. This is also done so that desktop programs and games look correct on the HDTV. If you use the other input labels, then ONLY
video will look correct and ONLY
if you make the appropriate settings, which I'm not covering here.
2) Because you're using the full 0-255 RGB color you'll have to make some setting adjustments so video looks correct. Under the "Video - Adjust Video Color Setting" you'll make changes under the "Color" tab as follows. Color: Brightness 58% and Contrast 48%. Under the Advanced tab make sure the "Dynamic Range" is set to "Full 0-255". I also set the gamma for all colors to .92. Note: In the research I've done, people have the Brightness set to 57% but I've noticed that blacks are a bit more crushed but not by much. You can avoid making these video adjustments and selecting the 16-235 range under the Advanced tab. If you do so you'll need to reduce the brightness (HDTV settings) to 51. The picture quality looks similar but I find that the skin tones look a tad bit more neutral and there's a bit less black crush when using the 0-255 setting with the manual corrections.
3) Under the "Display" settings set make sure Nvidia is set and use the defaults. Also, Make sure "RGB" is used with "Desktop Programs". The reason for this is nearly all programs on the PC will output 0-255. Plus with the settings in step 2, you're adjusting for the color space difference.Brilliant
Color: 32 for TV and 30 for movies
Video Noise: Off
Color Temperature: HighBright
Not used - Colors/Whites are too blown out and darks are crushed.Natural
Not used - Colors are not saturated enough, bright reds are too muted.
Using these settings XBMC produces VERY good picture results. But please make sure that "hardware acceleration" is checked. If not, you'll see serious black crush. That's in part because you won't be using the settings you made in step 2.
With Windows 7 Ultimate Media Center use the registry setting which will force Windows 7 Ultimate Media Center to output 0-255. With Sports, bright yellows can be a bit off - more to the green than yellow. But if you try to correct for this (tint) then you'll get more brown colors on a football field than green. This is because of the limited tint adjustment on the C10/638 HDTVs (single tint adjustment from green to red).
Boxee is a problem since I have to disable the "hardware acceleration" for the TWiT.TV plugin to display video shows, otherwise it only outputs audio. I only use Boxee for TWiT.TV and Revision3 programs so it's not that big of a deal for me. I would use XBMC for these plugins but the shows appear to be low-def in XBMC vs. higher resolution in Boxee. Again, there might be a setting change to resolve this issue with XBMC, eliminating the need to use Boxee at all.
Here's the Windows Media Center registry setting which will allow you to switch from 16-235 to 0-255. In the settings I gave above you should use the 0-255 settings.Windows Media Center registry settings (16-235 and 0-255)