1080/24 at 48Hz, 96Hz, or 120Hz - High-Def Digest Forums
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Old 01-18-2009, 07:05 PM
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Default 1080/24 at 48Hz, 96Hz, or 120Hz

Whats the difference? Whats the good and bad about it? Admittedly I DON'T know everything, and this is one of the few things I can't understand. If 120Hz is the DESIRED LCD TV refresh, but a front projector I'm looking at does 1080/24 at 48Hz....will I be disappointed? Will there be blur? What the hell does it all mean?
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Old 01-18-2009, 07:49 PM
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Movies are shot at 24 frames per second, but 24 refreshes per second by itself is not enough to remove flicker. Movies theatres show each frame twice giving a 48Hz refresh which is accepted by them (and what most people are therefore used to seeing) as good enough to remove flicker.

Getting a display with a multiple of 24Hz capable means that you will see films in their "natural" 24 frames per second.

Most DVD and Blu-ray players give you movies at 60 frames per second, with a 3-2 pulldown (one frame 3 times, the next one twice). Many Blu-ray players are now capable of providing 1080p24 instead of 1080p60.

Just having a display refresh at a multiple of 24Hz doesn't mean that it is giving you a X-X even pulldown. Many 120Hz LCDs give you 6-4 not 5-5.

Read this thread here to see which TVs properly display 1080p24.

Note that although most 48-72-96-120 are great and show no flicker, the Panasonic plasmas have a problem and at the 48Hz they display many people see flicker. This is not true of all 48Hz displays.
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Old 01-18-2009, 08:21 PM
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Quote:
Originally Posted by rick240 View Post
Movies are shot at 24 frames per second, but 24 refreshes per second by itself is not enough to remove flicker. Movies theatres show each frame twice giving a 48Hz refresh which is accepted by them (and what most people are therefore used to seeing) as good enough to remove flicker.

Getting a display with a multiple of 24Hz capable means that you will see films in their "natural" 24 frames per second.

Most DVD and Blu-ray players give you movies at 60 frames per second, with a 3-2 pulldown (one frame 3 times, the next one twice). Many Blu-ray players are now capable of providing 1080p24 instead of 1080p60.

Just having a display refresh at a multiple of 24Hz doesn't mean that it is giving you a X-X even pulldown. Many 120Hz LCDs give you 6-4 not 5-5.

Read this thread here to see which TVs properly display 1080p24.

Note that although most 48-72-96-120 are great and show no flicker, the Panasonic plasmas have a problem and at the 48Hz they display many people see flicker. This is not true of all 48Hz displays.
I feel so dumb after reading that post.

Well said nonetheless.
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Old 01-18-2009, 08:35 PM
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I worked at a movie theater, projection tech/projectionist/manager, and film is shot at 24 frames per second and shown 24 frames per second. There are no double frames. When things goto video, is where I get confused.

So what you are saying is, as long as its a multiple of 24, it will be ok? 60 divided by 24 is 2.5...??? Whats up with that? A lot of standard LCD panels refresh at 60hz, is that where the pull down comes in? If so, why do 120hz TV's have pull down if 120 is divisible by 24?

Should we all sell our crap and buy movie projectors just to keep this simple???
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Old 01-19-2009, 09:13 AM
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Originally Posted by Chickengas View Post
I worked at a movie theater, projection tech/projectionist/manager, and film is shot at 24 frames per second and shown 24 frames per second. There are no double frames.
The wheel infront of the projector has holes in it such that each frame is seen twice per second thereby giving at 48Hz refresh rate to avoid flicker.

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Originally Posted by Chickengas View Post
When things goto video, is where I get confused.

So what you are saying is, as long as its a multiple of 24, it will be ok? 60 divided by 24 is 2.5...??? Whats up with that? A lot of standard LCD panels refresh at 60hz, is that where the pull down comes in? If so, why do 120hz TV's have pull down if 120 is divisible by 24?
To show 24 frame source at 60Hz you get 3:2 pulldown; one frame 3 times the next frame twice. This is how we have always been watching movies on our TVs until 24p capable Blu-ray players and 24p capable TVs have come along. As noted before, not all 120Hz TVs to an even pulldown; many do the standard 3:2 pulldown to 60Hz and then just double it.

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Originally Posted by Chickengas View Post
Should we all sell our crap and buy movie projectors just to keep this simple???
If the 3:2 pulldown effects have never bothered you then don't worry about it. 24p capable systems just give the opportunity for smoother movies; the number of 24p capable systems will likely increase.
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Old 01-19-2009, 01:45 PM
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Id like to learn more about this

My PS3 is putting out 1080/24
my tv is set to 120 hz

At first it looked very weird, almost fake err i dont know how to explain it.
Love it know though! - everything flows on screen - looks like im watch a soap!

Now when i send the signal to my Optoma HD 65, should i change the out put of my ps3? turn 24hz off?
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Old 01-19-2009, 01:46 PM
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^^^
Are you sure you don't have some sort of motion enhancer turned on? I know us guys don't like doing this but you might want to check your user manual against how your TV is configured and see if it's in a mode where motion enhancer software would be activated.
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Old 01-19-2009, 01:56 PM
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Originally Posted by crazzeto View Post
^^^
Are you sure you don't have some sort of motion enhancer turned on? I know us guys don't like doing this but you might want to check your user manual against how your TV is configured and see if it's in a mode where motion enhancer software would be activated.
I have Cinema mode on and True motion - low on the Lg scarlett
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Old 01-19-2009, 02:59 PM
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Originally Posted by cpus456 View Post
I have Cinema mode on and True motion - low on the Lg scarlett
According to the Sticky thread at the top of the Home Theater Gear section, yours only works right

"LG 42LG60 (1080P/24 correctly refreshed at 120HZ when Truemotion is off and Real Cinema is on)"
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Old 01-19-2009, 04:10 PM
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The wheel infront of the projector has holes in it such that each frame is seen twice per second thereby giving at 48Hz refresh rate to avoid flicker.
Well, not to argue, but projectors have shutters not holes. One blade to four blade, if the blade isn't timed properly, you get flicker (strobing). At the speed that the blade turns, its very possible it shoots each frame onto the screen twice per second, never really gave it that much thought. Getting back to pulldown, 1080p/24 is going to be noticably better then? What kind of problems are seen with pulldown? Also, whats 4:4:4? This is good info to have..thanks!
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