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From what I've managed to ascertain by reading postings here, the X1 is natively capable of rendering 48hz source (2 x 24), but NOT 72hz source (3 x 24).


As I understand it, the X1's Faroudja chipset automatically recognizes film-source material and decodes it to nice, clean 24p, then triple-buffers the output and ultimately outputs each frame two or three times in a row while the next whole frame is being decoded.


On one hand, I want to give Nyquist the benefit of doubt and assume that the ultimate framerate is irrelevant as long as it's at least twice the native framerate of the source. At least, that's what Microsoft wants developers to believe (hunt around msdn.microsoft.com for their whitepaper on temporal rate conversion). If Nyquist was right and there aren't any gremlins lurking in the shadows, 24fps material shown at 48fps and 60fps should be visually indistinguishable.


On the other hand, I suspect Nyquist falls apart in this case, because 24fps is WAY too slow to begin with, and all the motion artifacts introduced by it will ultimately surface and ultimately look a LOT worse at 3:2 60hz than at 2:1 48hz.


The first question is, has anybody actually experimented with a HTPC and an X1 to test this theory? Say, by ripping a few minutes of film-source video from a DVD, de-interlacing it to 24p, then using THAT to create 48 and 60hz AVI files for viewing and comparing the two? What was the result? Flawless, judder-free and silky-smooth flowing video? Possibly marred by severe rainbows since the color wheel slows down for 48hz? A complete disaster and train wreck with horrible quality, tearing, etc? Or worst of all, NO IMPROVEMENT WHATSOEVER because Nyquist might have been right after all, and the X1's own Faroudja circuitry did a better job than, say, TMPGenc at deinterlacing it?


On the other hand, if it DID look better, how exactly did you go about obtaining the 48hz source? Did you have to rip and transcode the whole DVD, or is there some awesome DVD viewing app that can deinterlace and transcode to 48hz on the fly? Did you scale the output to 13:9 within an 800 x 600 frame and feed THAT to the X1, or did you just leave it at some other resolution and let the X1 worry about scaling it to fit and handling the aspect ratio?
 

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You can do the same thing by getting PAL and NTSC versions of the same DVD if you have a region-free PAL and NTSC player. PAL is 50Hz with a 4% speedup, but you do get 2:2 pulldown, instead of 3:2.


From my experience, the difference is most noticible on panning scenes.
 
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