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I tried doing some searching on 120hz, but my returns always have so many hits that it's impossible to even know where to start.


I have an HTPC with an ATI 5450 which is currently connected to a 60hz Vizio. I'm looking to purchase a 120hz set since 24p isn't compatible with 60hz. (I get it so far.)


SO. When I get a 120hz set, do I have to set my output on my HTPC to a specific refresh rate? This is where I need some schooling or a "How To" link. I want to get my bluray rips as smooth as possible.


Also what about HDMI through my receiver for bit-streaming? Does this play into anything with 120hz?


Thanks so much in advance.
 

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Very few, if any, TVs accept a 120Hz video signal. They generally accept 24, 30, 60 display those frames multiple times at the 120Hz rate. IOW, a each 24 signal image is displayed five times in a row, a 30 signal is displayed four times and a 60 image is displayed twice each.


The 120Hz refresh rate is completely internal to the TV and has nothing to do with the input signal rate.

Some displays can accept 48 and 72Hz signals but it is extremely rare for anything faster in the "video" world.
 

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Discussion Starter · #3 ·
So if I leave my output at 60hz the math should work out? Or should I put my HTPC output to 24hz? My bluray rips are all 24p, but what about other sources? Will they play okay? DVD rips etc?


Thanks so much in advance. I'm such a noob at this display stuff.
 

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Quote:
Originally Posted by Veeper /forum/post/20796485


So if I leave my output at 60hz the math should work out? Or should I put my HTPC output to 24hz? My bluray rips are all 24p, but what about other sources? Will they play okay? DVD rips etc?


Thanks so much in advance. I'm such a noob at this display stuff.

This is the constant question with htpc's. Theres no easy answer. And there is no simple solution like a blu ray player that will automatically detect the framerate and change it for you. It can be set up but its not the easiest thing to do.


The purists here will tell you to switch you refresh rate to 24hz, actually 23hz is what you want. No graphics cards seem to do 23.976 perfectly. I spent a lot of time futzing with it. I finally decided that 60hz looks just fine to me and i leave it alone.


I suggest trying a movie at both speeds. If 60 is fine for you don't bother. If its not then open up that can of worms.
 

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In NTSC countries, basically there are only two fps (after properly deinterlaced or inverse telecined):


- 23.976 fps (all movies)

- 59.94 fps (all videos)


If your (progressive) TV supports only 60Hz (that usually supports 59.94Hz too), there is no problem if you select "59Hz" (= ~59.94Hz) desktop refresh rate. Frames of a movie are repeated in a 2:3 pattern:


1 2 3 4 ... -> 1 1 2 2 2 3 3 4 4 4 ...


23.976 x (2+3)/2 = 59.94. People in NTSC countries are accustomed to this pattern (hence do not complain).
 

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Quote:
Originally Posted by renethx /forum/post/20796764


In NTSC countries, basically there are only two fps (after properly deinterlaced or inverse telecined):


- 23.976 fps (all movies)

- 59.94 fps (all videos)


If your (progressive) TV supports only 60Hz (that usually supports 59.94Hz too), there is no problem if you select "59Hz" (= ~59.94Hz) desktop refresh rate. Frames of a movie are repeated in a 2:3 pattern:


1 2 3 4 ... -> 1 1 2 2 2 3 3 4 4 4 ...


23.976 x (2+3)/2 = 59.94. People in NTSC countries are accustomed to this pattern (hence do not complain).

Not really true...2-3 pulldown judder drives me nuts on slow pans...Hence I use 72Hz (71.928) or 23.976X3 on my old CRT projector.
Some folks notice it some don't.

http://en.wikipedia.org/wiki/Telecine#Telecine_judder



BTW your simple description of 2-3 pull down is the best I've ever seen.


Mike
 

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Quote:
Originally Posted by whiteboy714 /forum/post/20796559


The purists here will tell you to switch you refresh rate to 24hz, actually 23hz is what you want.

The way to know the actual rate is to divide the "common" number by 1.001, for instance:
  • 24/1.001=23.976
  • 30/1.001=29.970
  • 60/1.001=59.940
 

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Quote:
Originally Posted by MikeEby /forum/post/20797474


Not really true...2-3 pulldown judder drives me nuts on slow pans

Absolutely!
 

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It's more like 24p judder (not enough frames) than 2:3 judder (unevenness), isn't it? The Big Judder Problem... (ProjectorCentral.com). Frame interpolation is the only solution for a large screen + a projector.
 

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Quote:
Originally Posted by renethx /forum/post/20798017


It's more like 24p judder (not enough frames) than 2:3 judder (unevenness), isn't it?

3:2 "Judder", the uneven motion that is continuous through the film, is what makes me puke. 24Hz strobing is what it is but is easily diminished by 2:2 or 3:3
Quote:
Frame interpolation is the only solution for a large screen + a projector.

I humbly disagree.
 

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Quote:
Originally Posted by Veeper /forum/post/20796485


My bluray rips are all 24p, but what about other sources? Will they play okay? DVD rips etc?

Ideally play everything at its original "native" rate or an even multiplier (same diff) for the minimum deterioration.
 

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Quote:
Originally Posted by cavu /forum/post/20798229


3:2 "Judder", the uneven motion that is continuous through the film, is what makes me puke. 24Hz strobing is what it is but is easily diminished by 2:2 or 3:3


I humbly disagree.

2:2 or 3:3 is the same as MikeEby.. BTW what display do you use?


Edit: Never mind. Infocus IN76, a projector (with a 92" screen), the same as MikeEby. I would like to hear experience from more people in the NTSC world, in particular users of relatively small (
 

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Quote:
Originally Posted by renethx /forum/post/20798396


2:2 or 3:3 is the same as MikeEby.. BTW what display do you use?


Edit: Never mind. Infocus IN76, a projector (with a 92" screen), the same as MikeEby. I would like to hear experience from more people in the NTSC world, in particular users of relatively small (
 
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