Are there any true 120Hz LCD TVs? - AVS Forum
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post #1 of 106 Old 10-14-2010, 08:07 PM - Thread Starter
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By true I mean 120Hz refresh rate, not this frame-interpolation "fad".
In 36"-40" range preferable.
I ask cause it would allow shutter 3d glasses (PC as input) to work, right?
Thanks
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post #2 of 106 Old 10-14-2010, 08:09 PM
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I dont believe there are any LCD televisions that accept a 120Hz signal input.
However nvidia are going to be releasing software shortly that will output the correct format for 3DTVs (double-height 60Hz rendering) from games instead of using their 120Hz 3D vision system.
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post #3 of 106 Old 10-14-2010, 09:00 PM
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There's no true 120Hz TVs in affordable price ranges. I heard there might be a commercial grade one someone makes, but it costs over $5000 or something.

Typically hooking a PC to an HDTV, which most support now, is done via HDMI, DVI, or VGA. HDMI and DVI will give you HD video quality. VGA however is analog and not as high res.
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post #4 of 106 Old 10-15-2010, 01:47 AM
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Really?? Wow, because I was looking at 120hz TVs because I want to play 1080p 24fps movies.

So all the LCD TVs that advertise a 120hz refresh rate are actually using software to mimic that? What about LED TVs?

If that's the case, is there any point then in paying extra for a 120hz TV?

Thanks
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post #5 of 106 Old 10-15-2010, 02:33 AM
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I thought 120hz was simply the refresh rate. It is what it is. That has nothing to do with the frame interpolation the OP speaks of.

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Of course, I got it modified with the TK-427, which cheeks it up another, maybe, 3 or 4 quads per channel.
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post #6 of 106 Old 10-15-2010, 02:36 AM
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Quote:
Originally Posted by mzaur View Post

Really?? Wow, because I was looking at 120hz TVs because I want to play 1080p 24fps movies.

So all the LCD TVs that advertise a 120hz refresh rate are actually using software to mimic that? What about LED TVs?

If that's the case, is there any point then in paying extra for a 120hz TV?

Thanks

The panel still refreshes at 120Hz, it just cannot accept a 120Hz input from an external source. It will accept a 24Hz input and play back at 120Hz though and can interpolate a 60Hz input to 120Hz.

For 3D, PCs use a method that renders two frames at the target resolution or 1280x720 @ 120 Hz for 720p60 3D.

3DTVs work differently and use double-height rendering with a gap at the refresh rate. So 720p60 3D using this method would actually be 1280x1500 @ 60 Hz. (720x2 +60)

Nvidia is going to release "3DTV Play" software that lets you play "3D Vision" games (120Hz) using the 3DTV method. (60Hz double-height)
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post #7 of 106 Old 10-15-2010, 06:47 AM - Thread Starter
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Quote:
Originally Posted by Chronoptimist View Post

The panel still refreshes at 120Hz, it just cannot accept a 120Hz input from an external source. It will accept a 24Hz input and play back at 120Hz though and can interpolate a 60Hz input to 120Hz.

Are you sure it's true for all 120Hz tvs? I was looking at Sony 40EX402 vs 40ex500 and on the spec sheet for the ex500 is says 60p and people mention both models use the same panel and ex500 just has "120Hz frame-interpolation". I'll look a bit into it.

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For 3D, PCs use a method that renders two frames at the target resolution or 1280x720 @ 120 Hz for 720p60 3D.

3DTVs work differently and use double-height rendering with a gap at the refresh rate. So 720p60 3D using this method would actually be 1280x1500 @ 60 Hz. (720x2 +60)

Nvidia is going to release "3DTV Play" software that lets you play "3D Vision" games (120Hz) using the 3DTV method. (60Hz double-height)

That sounds awesome. Damn. It seems I'll have to get a 120Hz set
Care to recommend some?
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post #8 of 106 Old 10-15-2010, 06:50 AM
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I’ve seen your other post…. If you are looking for good LCD TV in EU, do not consider anything else but Philips...

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post #9 of 106 Old 10-15-2010, 06:52 AM
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Almost all 120Hz TVs can do either frame interrpolation of 60fps content or display 24fps content using 5:5 pulldown to display each frame 5 times to elimnate 3:3 Pulldown Juddder.
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post #10 of 106 Old 10-15-2010, 07:04 AM
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Aren't European TV's 50hz/100hz rather than 60hz/120hz as in the US?
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post #11 of 106 Old 10-15-2010, 07:27 AM
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Only AV processor board (tuners) are 50 or 60 Hz. (LCD panels/T-con board) combo are equally 50 (100) as they are 60 (120) Hz

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post #12 of 106 Old 10-15-2010, 07:59 AM
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Quote:
Originally Posted by zoran0909 View Post

Are you sure it's true for all 120Hz tvs? I was looking at Sony 40EX402 vs 40ex500 and on the spec sheet for the ex500 is says 60p and people mention both models use the same panel and ex500 just has "120Hz frame-interpolation". I'll look a bit

This is a tough concept to understand due to the strong marketing efforts made by manufacturers and lack of clear explanations but I'll try and explain.

High refresh rates [e.g -120Hz, 240Hz, 480Hz...etc] are an "enabling" technology. They do nothing to the picture. They are only there to "enable" other technologies to be used.

What they do is "enable" (i.e - make possible) the use of frame interpolation, BFI, and cadence adjustment to combat blur and judder.

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post #13 of 106 Old 10-15-2010, 08:09 AM - Thread Starter
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Quote:
Originally Posted by Extreme_Boky View Post

Only AV processor board (tuners) are 50 or 60 Hz. (LCD panels/T-con board) combo are equally 50 (100) as they are 60 (120) Hz

I've seen your other post. If you are looking for good LCD TV in EU, do not consider anything else but Philips...

Yeah, the admin locked the thread already, as if someone's gonna answer my question in the monster "help me choose" thread (where I first posted, and of course no one took notice).

Why do you say I should get a Philips?
Why not a Samsung or a Sony?

BTW, I had college exams which took lest time to prepare than just getting up to speed with TV tech
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post #14 of 106 Old 10-15-2010, 08:21 AM
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Quote:
Originally Posted by Extreme_Boky View Post

I’ve seen your other post…. If you are looking for good LCD TV in EU, do not consider anything else but Philips...

Boky


This is wrong suggestion. Philips TVs aren't magical. Sony and Samsung can be the same or even better in some cases.
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post #15 of 106 Old 10-15-2010, 09:18 AM - Thread Starter
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Quote:
Originally Posted by xrox View Post

This is a tough concept to understand due to the strong marketing efforts made by manufacturers and lack of clear explanations but I'll try and explain.

High refresh rates [e.g -120Hz, 240Hz, 480Hz...etc] are an "enabling" technology. They do nothing to the picture. They are only there to "enable" other technologies to be used.

What they do is "enable" (i.e - make possible) the use of frame interpolation, BFI, and cadence adjustment to combat blur and judder.

Eh? It's not a tough concept, either it's 120Hz panel or it's not.
MotionFlow and similar is just post processing which smart PC users were doing for years. If you have a higher refresh rate then the source, you can do frame-interpolation.
From what I gather up to now, most of "120Hz" tv's are just using 60Hz panels and fancy PP.
If they were using 120Hz panels, they would accept 120Hz signal, no? But they don't

Ah, I yearn for the day when LCD will match up with my trinitron displays.
Luckily I still have and use my 21" Dell (Sony trinitron tube) which will happily do real 170Hz (though 120hz only up to 1344x1008), and 0ms input lag

BTW: 3DTV Play seems to target just a few TV set which already support some kind of 3d, so even if a TV uses 120Hz panels, it won't support 120Hz nor 3DTV 1280x1440@60p
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post #16 of 106 Old 10-15-2010, 09:46 AM
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Quote:
Originally Posted by zoran0909 View Post

Eh? It's not a tough concept

Judging by the misinformation regularly posted here on this topic I would have to disagree.

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Originally Posted by zoran0909 View Post

MotionFlow and similar is just post processing which smart PC users were doing for years. If you have a higher refresh rate then the source, you can do frame-interpolation.

Sounds here like you understand fine.

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Originally Posted by zoran0909 View Post

From what I gather up to now, most of "120Hz" tv's are just using 60Hz panels and fancy PP.
If they were using 120Hz panels, they would accept 120Hz signal, no? But they don't

What makes you gather this after seemingly understanding just fine one sentence ago?

As you said yourself, a higher refresh rate enables use of frame interpolation (among other things). I think you are just stuck on the thought that a high refresh rate panel must have a high refresh rate input which is in no way true.

The 120Hz and 240Hz panels (excluding hybrid backlight scanning) on the market are in fact refreshing the panel at those frequencies. They just cannot accept signals at those frequencies.

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post #17 of 106 Old 10-15-2010, 10:55 AM
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Quote:
Originally Posted by xrox View Post

Judging by the misinformation regularly posted here on this topic I would have to disagree.

Sounds here like you understand fine.

What makes you gather this after seemingly understanding just fine one sentence ago?

As you said yourself, a higher refresh rate enables use of frame interpolation (among other things). I think you are just stuck on the thought that a high refresh rate panel must have a high refresh rate input which is in no way true.

The 120Hz and 240Hz panels (excluding hybrid backlight scanning) on the market are in fact refreshing the panel at those frequencies. They just cannot accept signals at those frequencies.

The heirarchy for quality of motion blur reduction is:

1) true 240 hz
2) quasi 240 Hz (120 Hz with scanning back-lght)
3) 120 hz
4) 60 Hz

Even so, some 120 Hz panels do no better than some 60 Hz panels with motion blur reduction because a lot depends on how the 120 Hz is implemented.

The best 120Hz and higher do a very good job of reducing motion blur.
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post #18 of 106 Old 10-15-2010, 11:12 AM - Thread Starter
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Quote:
Originally Posted by xrox View Post

As you said yourself, a higher refresh rate enables use of frame interpolation (among other things). I think you are just stuck on the thought that a high refresh rate panel must have a high refresh rate input which is in no way true.

Yes, I'm kinda stuck on it as it's logical and it makes sense, I mean, how much can it cost to just pass through the signal without PP? It would make sense from a marketing perspective too, another shiny badge on the box.

Sure there's not much 120Hz ATM (if you ignore games and iZ3d/nVidia) but it's still worth it to the manufacturer as a marketing ploy.
I guess I just didn't want to accept that much stupidity


Quote:
The 120Hz and 240Hz panels (excluding hybrid backlight scanning) on the market are in fact refreshing the panel at those frequencies. They just cannot accept signals at those frequencies.

Hmmpf, ok, if you say so. I'm only starting to scratch the surface on this whole newfangled "thin" TV business.
A quote from a few users stating the Sony's EX400 and EX500 use the same panels but EX500 has BE3 and MotionFlow (Sony's specs sheet lacks any clear info on the refresh rate) got me on the wrong track, or maybe it's true for this particular model?

Also can you please point me to some current models worth checking out?

I really tried to get some info from the net but it's just garbage and stupid shop aggregation sites. I have yet to find a site that does consistent and quantifiable tests (like say, tft-central for monitors). This whole obfuscation/mystification/marketing drivel is driving me nuts.

What do STARS mean? How does a 5.5 score translate to ms of input lag? How does a "good viewing angle" do vs a "tight" one? Etc, etc.
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post #19 of 106 Old 10-15-2010, 11:16 AM
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Quote:
Originally Posted by spyboy View Post

The heirarchy for quality of motion blur reduction is:

1) true 240 hz
2) quasi 240 Hz (120 Hz with scanning back-lght)
3) 120 hz
4) 60 Hz

Even so, some 120 Hz panels do no better than some 120 Hz panels with motion blur reduction because a lot depends on how the 120 Hz is implemented.

The best 120Hz and higher do a very good job of reducing motion blur.

I prefer the word "hybrid" when describing #2. As for any heirachy I would only suggest so on the objective basis of display hold-time.

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post #20 of 106 Old 10-15-2010, 11:40 AM
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Quote:
Originally Posted by zoran0909 View Post

Also can you please point me to some current models worth checking out?

Unfortunately I am only interested in how the tech works (for my work). Regarding specific models I am a putz. Since I purchased my display 2 years ago I haven't kept up with new models so I am the last person you should ask .

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Originally Posted by zoran0909 View Post

I really tried to get some info from the net but it's just garbage and stupid shop aggregation sites. I have yet to find a site that does consistent and quantifiable tests (like say, tft-central for monitors). This whole obfuscation/mystification/marketing drivel is driving me nuts.

What do STARS mean? How does a 5.5 score translate to ms of input lag? How does a "good viewing angle" do vs a "tight" one? Etc, etc.

I hear you. It is hard to believe people make decisions based on such info. Unfortunately, in most cases the info given by retail salespeople is even worse.

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post #21 of 106 Old 10-15-2010, 11:50 AM
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Quote:
Originally Posted by xrox View Post

I prefer the word "hybrid" when describing #2. As for any heirachy I would only suggest so on the objective basis of display hold-time.

And I would only suggest that professional testers who use a variety of source material including specially designed test patterns as well as sports, action movies, and video games be used, as well as other practical tests are just fine for even average hobbiests.

People whose work takes them in a different direction can look for display hold-times where ever they can be found. I hope you don't mean the input lag thread.
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post #22 of 106 Old 10-15-2010, 11:58 AM
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Originally Posted by spyboy View Post

And I would only suggest that professional testers who use a variety of source material including specially designed test patterns as well as sports, action movies, and video games be used, as well as other practical tests are just fine for even average hobbiests.

Feel free to suggest whatever you like. I only pay attention to true display R&D (I would not even include some manufacturer white papers in that )

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Originally Posted by spyboy View Post

People whose work takes them in a different direction can look for display hold-times where ever they can be found. I hope you don't mean the input lag thread.

You lost me??

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post #23 of 106 Old 10-15-2010, 12:12 PM - Thread Starter
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Quote:
Originally Posted by xrox View Post

Unfortunately I am only interested in how the tech works (for my work). Regarding specific models I am a putz. Since I purchased my display 2 years ago I haven't kept up with new models so I am the last person you should ask .

Oh well.
But so, can you confirm or correct some of my assumptions:
  • IPS has better color rendition than xVA tech?
  • IPS has better viewing angles than xVA?
  • IPS has lower input lag than xVA?
  • That I just can't generalize like this, but need to compare specific implementation and generation of tech used?
  • I should just give up on real 120Hz input tv's? (or just settle for proper 1080@24p implementation)

Quote:
I hear you. It is hard to believe people make decisions based on such info. Unfortunately, in most cases the info given by retail salespeople is even worse.

Retail people here are much much much much worse. A lot of TV's are still fed analog SD signal/otv SD-DTV in the bast case and such s*te.
They even managed to *uck up a Toshiba plasma+blu ray combo with a demo blu-ray disc playing. It looked barely on par with scene releases of 720p hdtv, not even close to a proper x264 encode. I can't even begin to imagine how can one fsck that one up so bad. Stupid.

Oh, and I forget, THE MARKUP. The CHEAPEST online store here, has the Sony 40ex402 for $1000 us vs the US where the same set is just $600 at Walmart.
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post #24 of 106 Old 10-15-2010, 12:40 PM
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Quote:
Originally Posted by zoran0909 View Post

Oh well.
But so, can you confirm or correct some of my assumptions:
  • IPS has better color rendition than xVA tech?
  • IPS has better viewing angles than xVA?
  • IPS has lower input lag than xVA?
  • That I just can't generalize like this, but need to compare specific implementation and generation of tech used?
  • I should just give up on real 120Hz input tv's? (or just settle for proper 1080@24p implementation)

I can't because I do not know liquid crystal materials/orientation tech that well (not very confident). I can maybe find you a solid R&D journal that may answer some questions for you though. There are also a few posters here with solid knowledge of LC materials.

As for 120Hz inputs, until sources threaten to become ubiquitous you probably won't see it.

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Originally Posted by zoran0909 View Post

Oh, and I forget, THE MARKUP. The CHEAPEST online store here, has the Sony 40ex402 for $1000 us vs the US where the same set is just $600 at Walmart.

I'm in Oakville Ontario and I struggled with the markup for years until I found a group buy (started on AVS) that saved me 30% and even then I paid more that most do in the US.

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post #25 of 106 Old 10-15-2010, 12:57 PM
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Again, you will not find a true 120Hz (or higher) actual refresh on a consumer grade TV. The so called "120Hz" spec is in reality processing that tries to simulate higher refresh by calculating what objects are moving onscreen, creating a fake frame with mostly just those objects recreated, and inserting it between the 60Hz frames. Now if you can really call that 120Hz, I've got some swamp land to sell you at top dollar.

The manufacturers are at least getting a bit more honest it about it by calling it 120Hz "motion processing". That is why even a lot of salesmen are not trying to BS people about sets having true 120Hz anymore. If you're read up on it, and convey that in talking to them, they know better than to try and con you.

Typically motion processing varies from brand to brand in how well it's done, and gets better with each generation. Most brands are on about their 4th or more gen of it now. It's also less noticeable on smaller screens. With motion processing though, it's a double edged sword.

There's a fine line between MP looking horrible, not being noticeable at all, and making a subtle beneficial difference. The latter is all you can really hope for. The factors that determine which of the 3 you get will be screen size, gen & method of motion processing, panel type, and source material viewed.

It's not uncommon to hear complaints that with MP turned on, film based material can suddenly look like video and fake. As fast as the MP has to prebuffer and calculate moving objects, it's really hard for it to recreate each frame identically.

A common complaint about MP is it has a hard time simulating the background content being out of focus. Thus the inserted fake frames, though fairly accurately simulating where the moving objects would be located in between the 60Hz frames, look noticeably different in overall content.

The double edged sword comes into play mostly when you have a larger screen that benefits more from the moving object calculation, but at the same times results in the difference in background content being more noticeable.
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post #26 of 106 Old 10-15-2010, 01:27 PM
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Quote:
Originally Posted by Hi Def Fan View Post

Again, you will not find a true 120Hz (or higher) actual refresh on a consumer grade TV.

This is a good example of why confusion arises on this topic. You are literally stating that the panel does not refresh at 120Hz (even though I think you know it does).

The panel refreshes (i.e - applies data) to the pixels 120 times a second (no matter what). Therefore the "panel" is 120Hz and has a 120Hz refresh rate. The question is whether or not it accepts a 120Hz signal and the answer is no.

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post #27 of 106 Old 10-15-2010, 01:56 PM
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I thought the panel refreshed at 60hz but with interpolation for 120hz.

Now I am really confused.
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post #28 of 106 Old 10-15-2010, 02:21 PM
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LCD panels work together with T-CON board and are of native resolution 720 or 1080 pixels (can address / control either 720 or 1080 vertical pixels). They work equally well together at either 50 or 60 Hz.
If one gets 120Hz LCD TV, LCD panel will always work at 2 X 60Hz; this 120Hz technology can be used for motion interpolation (where 1st and 3rd frame are stored, second calculated based on these stored frames and algorithm implemented by manufacturer, to smooth motion), but if one decides to switch off motion interpolation in settings, the TV will not wait for 3rd frame and there will be minimal lag (Viper Mode – Game Mode). In this mode each frame is displayed twice, unmodified (not interpolated). Getting fast TV (200 / 240Hz) also means that you are getting fast LCD panels <4ms and fast RAM / processor on T-CON board (also fast interface / cabling to sustain such high bandwidth between AV processor board - LVDS interface - T-CON board. The weakest link here is in fact differential interface between AV module and T-CON - hence manufacturers are now moving towards integrated AV module WITH T-CON board on one PCB - this improves performance substantially. There are also all-together benefits to be obtained in very low PCB ground noise environment needed for such fast data transfers (low noise, local on-the-PCB regulation)

Boky
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post #29 of 106 Old 10-15-2010, 02:26 PM
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Quote:
Originally Posted by pangadaywalker View Post

I thought the panel refreshed at 60hz but with interpolation for 120hz.

Now I am really confused.

The panel refreshes at 120hz and must upconvert all data to this refresh rate.

Think of it this way. The panel has 120 chances per second to send data to the pixels. If the panel recieves data with only 60 frames per second it must either repeat each frame twice or even better, create new frames (interpolation) or send black frames (BFI).

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post #30 of 106 Old 10-15-2010, 02:34 PM
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Quote:
Originally Posted by pangadaywalker View Post

I thought the panel refreshed at 60hz but with interpolation for 120hz.

Now I am really confused.

TV refresh rate and Motion Interpolation are two different things although under certain conditions they are working together.

120Hz refresh rate is fixed and you can not turn it off. If there is 60Hz signal then TV just repeats each frame twice and you have 120frames per second shown to your eyes 'as' 60 frames per second (you can't see difference between the same two frames).

Motion interpolation is another thing - it inserts additional frame (or frames) to make movement more smooth, but by inserting additional frame it does not repeat it, but creates new artificial frame. This time your eyes can already notice new stuff (new frames) and the whole action on the screen looks smoother. For MI (Motion Interpolation) to work, TV must be capable of 120Hz at least.
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