I'm glad to hear that you're going through with this concept. If I could make a suggestion: do try and make the drivers work cleanly with VMR9, and specifically the "renderless exclusive" mode. It's tough, because this mode seems to like to take control of the video hardware. That said, to my eye, it gives the smoothest playback.
Hi again Andy,
When I tried the nVidia the first time, I hammered out my color balance as well as my Spyder2Pro would allow. It was as close as I could get my Marquee 8000s to tracking D65, and visually indistiguishable to my eye.
Color balance aside, though, I suppose the gamma is the key to a transparent blend. I can't give a subjective assesment of the suitability of my projectors' gamma curve, but I know that the Marquee VIM circuitry was modified after the 8000 to alter gamma tracking. I would think that the designers at nVidia would have to use a particular gamma exponent as a given in designing the blend algorithms. I tried 2.2 and 2.5, and both showed the same band in the middle of the screen.
That said, it's only visible in a very small percentage of video material, but enough so and visibly enough that it really doesn't qualify, uncorrected, as a reference-type solution.
I don't mean to go off-topic, but if you get a chance, when you've set up your beast of a computer, do try the "overlay" avisynth functionality built into ffdshow. It lets you overlay a 32-bit RGB bitmap onto the pre-blend video frames, and has allowed me to just sit back and enjoy two blended CRTs, using the nVidia software.
Sorry for the intrusion, Luke, and I wish you the best in your efforts.