24Hz LCDs - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 3 Old 07-01-2006, 12:29 AM - Thread Starter
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Ive tried numerous times to figure this one out. To avoid pulldown, why cant an LCD be made to do 24hz, thus displaying a 24fps source at native rate.

Please dont bring up 72hz, or 120hz, as its obvious that since thats faster than 60hz, that it requires new tech. But 24hz should be easier to accomplish as it is slower. THen when viewing normal source go back to 60Hz.

Also dont bring up flicker. This is not a CRT question, LCDs are fixed pixeled and always remain lit, so even if it was a 5Hz LCD there would be no flicker.

Had to put on the limitations cause everytime i ask thats what the answers are, but they leave the main question un answered. Hoping someone can explain, thanks.

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post #2 of 3 Old 07-01-2006, 01:03 AM
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what about ghosting? i dunno how ms relate to fps, but it's suppose to be miliseconds, so mathematically:
8ms = 125 fps? i don't think they actually relate this way, doesn't make that much sense.
if 1000/24 = 41.6? that is 41.6ms for the frame rate, have u see some older lcd's with slower refresh rates? that is some poor slow lcd.
on the other hand, movies are recorded at 24fps, and most things output in 60 (rounded) fps. so I guess the industry standard is to make it at least fit the standard, then use hte 3:2 pulldown to get the 24fps to fit with the 60 fps thus receiving all the lcd's with higher than 60 hz.

not sure if this made any sense to anyone, i think i just confused myself a bit, i'll read it again tomorrow moring when my brain is cleared up.

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post #3 of 3 Old 07-01-2006, 07:44 PM
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Well, I just have to bring up 72 Hz, 'cause it's a nice multiple of 24 and does not require any "new tech". Current LCD PC monitors will usually run at 72 or 75, and some LCD TVs may also support those modes. However, no graphics card that I know of supports refreshes lower than 60 Hz, except in interlace mode. For example, creating custom refreshes on an NVidia card below 60 will cause the card to switch to interlace mode.

Also, no hardware video source does 24p (23.976p) as of yet. So if you don't have a PC source, you'll have to rely on the panel's IVTC.

Also, if you're viewing IVTC'd film (ie. internal IVTC or external) from NTSC source, the rate will be 23.976, requiring 71.928 Hz. And if your source is PAL, it will be 75 on the dot...

For your viewing pleasure, here's a few LCD TVs that can do 72 (and some 75 Hz. :))

Sony KLVS32A10 (56/60/72/73/75) [PC VGA input]

Planar XP37W (56-75)

And for more, here's a whole list of 75 Hz. LCDs.
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