120 VS 240 Refresh Rates - AVS Forum
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Old 09-08-2011, 03:24 PM - Thread Starter
 
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I read that 240 or above is a gimmick and anything can be successfully shown just as well with 120. True? False? Thoughts? I was purpsoely spending mroe for 240 and after reading that I am wondering again.
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Old 09-08-2011, 03:45 PM
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IMHO if you are interested in Blu-ray or 1080i TV content or possiby 3D content you should have a 240Hz unit not just a value priced 120Hz unit.
However if you only plan on deeping the TV a year or two 120Hz may be a better value.
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Old 09-08-2011, 03:56 PM
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Quote:
Originally Posted by walford View Post

IMHO if you are interested in Blu-ray or 1080i TV content or possiby 3D content you should have a 240Hz unit not just a value priced 120Hz unit.
However if you only plan on deeping the TV a year or two 120Hz may be a better value.

walford me boy could you elaborate a bit on that? I have a 120Hz LCD (no 3D, don't believe in it) and am thoroughly enjoying Blu-ray and 1080i OTA tv. What am I missing?
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Old 09-08-2011, 03:57 PM - Thread Starter
 
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I'm "hoping" to not buy another for 5+ years, but I'm always tempted to. But my point was some claimed 240hz adds nothing to it. If it defintiely improves motion noticably, I would stick with 240. I believe I also read that a 240 generally has more issues such as crosstlak I believe.
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Old 09-08-2011, 03:57 PM - Thread Starter
 
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yeah as far as that goes I think 1080i/p looks great on my Sony 60hz lcd from 5 years ago.
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Old 09-08-2011, 04:22 PM - Thread Starter
 
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By the way, just to come right out and say what the implications of this are, if 120 is good enough for me then I will get a 55 inch. If not then I will get a 47 inch. So 8 inches difference is at stake. I don't want to pay the higher amount for the 55 inch 240 most likely.
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Old 09-08-2011, 05:10 PM - Thread Starter
 
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So far, after searching online, I am leaning towards 120. Granted all articles I have read are from 2009 and 2010, but they almost all agree that the difference between 120 and 240 is only noticable to most people with test patterns.
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Old 09-09-2011, 01:31 AM - Thread Starter
 
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Here's a link with more recent discussion on this. Yet again it comes to the same conclusion. So I am definitely going for the 120 and then likely disabling it. My current tv is 5 years old so I assume I still ened an improvement on that, but if this article is correct then the default 60 will do on current sets.

This whole thing reminds me of digital cameras... People buying the higher pixel cameras. I eprsonally thought these refresh rates were legitimate though and that 120 wasn't fixing motion enough (despite never watching one to judge for myself).
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Old 09-09-2011, 04:19 AM
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You can't "disable" 120Hz. A 120Hz TV always operates at 120Hz. You can adjust it, however.

In my experience of selling TVs, in larger sizes, (eg: 55"+), 240Hz definitely helps. In larger sets, sample-and-hold blur inherent to LCDs is more readily noticeable and IMO 240Hz sets remedy this better than 120Hz ones do. Reading reviews you will often read that on most 120Hz sets motion resolution averages somewhere between 600-700 lines out of a 1080 image, generally 240Hz sets can resolve the full 1,080. Whether that is noticeable depends on your eyes and the size of display, but it is definitely measurable.

Again, articles like the one you linked from PCMag make me shake my head because they 1) tend to oversimplify things, and 2) quite frankly, the author doesn't really know what the hell he's talking about. E.G. he refers to the 600Hz subfield refresh of a plasma as "downright overkill," when in reality that number actually has nothing to do with the real effective refresh rate of a plasma, which, by the way, is still 60Hz. The refresh of a plasma and the 120/240 you find on an LCD is something entirely different.

Also, blur reduction and frame interpolation are not mutually exclusive. (On most sets) you can independently adjust blur reduction (frame repetition) and judder reduction (interpolation/smoothing).

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Old 09-09-2011, 08:51 AM
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Quote:
Originally Posted by fatuglyguy View Post


Also, blur reduction and frame interpolation are not mutually exclusive. (On most sets) you can independently adjust blur reduction (frame repetition) and judder reduction (interpolation/smoothing).

Blur reduction is a form of motion interpolation (without a smoothing effect). Repeating frames will not reduce motion blur on an LCD since the sample and hold nature of LCD will not allow the LCD to refresh until a different frame is shown. This is exactly why when watching 24Hz sources on an LCD, it doesn't matter whether 2:2, 5:5, or 10:10 pulldown is used. It all becomes 1:1 on an LCD.
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Old 09-09-2011, 10:13 AM
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Quote:
Originally Posted by midnight77 View Post

By the way, just to come right out and say what the implications of this are, if 120 is good enough for me then I will get a 55 inch. If not then I will get a 47 inch. So 8 inches difference is at stake. I don't want to pay the higher amount for the 55 inch 240 most likely.

FWIW, I have a 47" LG at 120Hz and I rarely see any issues with motion blur/studdering, etc that would make me want to return the set. Could be my eyes but nobody else in the family notices anything either whether we try to mitigate it with TruMotion (LGs term) on, off, or custom set.
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Old 09-09-2011, 10:23 AM
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If a frame from a 24fps source is left in an LCD displays software output buffer for 1/24th a second the frame since will be displayed 5 times since the 120HZ Timing control circuit will refreshs the actual screen 120 times a second using the content of the software output buffer. In this case there is no 3:2 pull down Judder since each frame is displayed the same number of times. The actual image on the screeen does not change it is just shown 5 times.
The content of the software output buffer obviously can not concurently contain interpolated frames between any other frames in order to smooth motion.
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Old 09-09-2011, 11:31 AM - Thread Starter
 
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Quote:
Originally Posted by fatuglyguy View Post

You can't "disable" 120Hz. A 120Hz TV always operates at 120Hz. You can adjust it, however.

In my experience of selling TVs, in larger sizes, (eg: 55"+), 240Hz definitely helps. In larger sets, sample-and-hold blur inherent to LCDs is more readily noticeable and IMO 240Hz sets remedy this better than 120Hz ones do. Reading reviews you will often read that on most 120Hz sets motion resolution averages somewhere between 600-700 lines out of a 1080 image, generally 240Hz sets can resolve the full 1,080. Whether that is noticeable depends on your eyes and the size of display, but it is definitely measurable.

Again, articles like the one you linked from PCMag make me shake my head because they 1) tend to oversimplify things, and 2) quite frankly, the author doesn't really know what the hell he's talking about. E.G. he refers to the 600Hz subfield refresh of a plasma as "downright overkill," when in reality that number actually has nothing to do with the real effective refresh rate of a plasma, which, by the way, is still 60Hz. The refresh of a plasma and the 120/240 you find on an LCD is something entirely different.

Also, blur reduction and frame interpolation are not mutually exclusive. (On most sets) you can independently adjust blur reduction (frame repetition) and judder reduction (interpolation/smoothing).

If you notice, someone responding to that article said you can't disable it either and they were told by multiple people that on most sets you can idneed disable it totally.
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Old 09-09-2011, 12:21 PM
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You can't disable 120hz. The set's going to refresh 120 times per second regardless.

What you can disable is the frame interpolation feature that 120hz sets have.

HD signals reach the set at 60 frames per second. Frame interpolation analyzes two real incoming frames and inserts an artificially "interpolated" intermediate frame between them.

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Old 09-09-2011, 12:31 PM - Thread Starter
 
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I'm just telling you what they said. Someone else said that also (you can't disable it, as it's its refresh rate and that refresh rates cant be magically changed), but people insisted you can. Not just the fancy features for motion, but the refresh rate itself.

So I don't know what's true, but the places I saw that mentioned nobody disagreed with them. Also I know on LG and Toshiba sets, for example, they don't ahve true 240 refresh rates. They do something involving flickering to make it "seem" like 240. So that may have been what they were turning off also as that isn't a true 240 refresh rate.
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Old 09-09-2011, 02:43 PM
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Quote:
Originally Posted by midnight77 View Post

I'm just telling you what they said. Someone else said that also (you can't disable it, as it's its refresh rate and that refresh rates cant be magically changed), but people insisted you can. Not just the fancy features for motion, but the refresh rate itself.

So I don't know what's true, but the places I saw that mentioned nobody disagreed with them. Also I know on LG and Toshiba sets, for example, they don't ahve true 240 refresh rates. They do something involving flickering to make it "seem" like 240. So that may have been what they were turning off also as that isn't a true 240 refresh rate.

I think that flickering is a backlight strobe effect that mimics 240Hz. Whether it can be turned on or off I don't know.
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Old 09-09-2011, 03:15 PM
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Actual panel refresh rates on tvs are not changeable, they may be on some Computer monitors, hence the misconception of some at PC magazine. I know lots of people who are very computer savvy who are totally clueless about tvs, and vice versa.

Backlight strobing is totally separate from refresh rates. It's analogous to what goes on with a film projector in a theater--the film runs through the projector at 24fps, but the projector shutter opens and closes twice on every frame to reduce flicker.

Usually you can look at the specs page at the back of a set's owner's manual to find the actual refresh rate of the panel.

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Old 09-09-2011, 03:53 PM
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a 120Hz LCd TV will show 120 native images per second reguardless of what you feed it.

When the source is 60 native images per second and Motion Interpolation(which adds artificial images) is turned off the 120 Hz LCd TV will double the 60 native images in order to get 120 images per second, dispite the 120 images it will perform as a 60Hz since all it does is show each imago twice - 60 images per second=60Hz - this is why some folks think 120Hz is turned off.


hemagazine: 240Hz
http://www.hemagazine.com/240Hz
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Old 09-09-2011, 04:04 PM
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You can not change the actual refresh rate on a LCD flat Panel TV. You can change the actual refresh rate on some Plasma flat panel TVs between 48,60,72 and 96 fps, and 120fps on 3D models.
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Old 09-09-2011, 04:26 PM
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Originally Posted by walford; View Post

You can not change the actual refresh rate on a LCD flat Panel TV. You can change the actual refresh rate on some Plasma flat panel TVs between 48,60,72 and 96 fps, and 120fps on 3D models.

And why is that? , is it to expensive or can't it be done?

120Hz can mimic a 240Hz(blackframe insertion), a 120Hz can mimic a 60Hz (60 frame doubling mimics a 60Hz).
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Old 09-09-2011, 04:45 PM
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HD signals reach the set at 60 frames per second. Frame interpolation analyzes two real incoming frames and inserts an artificially "interpolated" intermediate frame between them.

And how does that work? 60 native frames and 50 artificial frames? There are 10 frames missing, the endresult should be 120, right?

And what about Motion Interpolation low, mid, high? Is this in all cases 50 artificial frames?
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Old 09-09-2011, 06:00 PM
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From the research I have done there are different iterations of 240hz sets. The premise is to reduce to latency between our optics and brain since the panels utilizing S&H have a hold time which creates a smearing effect in our retinas once the set moves to the nest frame. The premise behind BFI is to refresh our eyes to allow smoother transition into the next frame. This can only be achieved (at least to the best of my knowledge) on a 240hz set.

Displays with local dimming flash the LEDs to mimic that of plasma which also reduces the blurring effect. The side effect to this is a "less Bright" display, which pumping out over 60Ftl is more than enough.
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Old 09-10-2011, 12:30 AM - Thread Starter
 
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Well if that's agreed upon I would of coruse rather have a 240, but when I am already paying mroe than I want for a 120 I would hate to then pay yet another $300+.
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Old 09-10-2011, 12:38 AM
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Quote:
Originally Posted by midnight77 View Post

Quote:
Originally Posted by fatuglyguy View Post

You can't "disable" 120Hz. A 120Hz TV always operates at 120Hz. You can adjust it, however.

Quote:
Originally Posted by Steve S View Post

You can't disable 120hz. The set's going to refresh 120 times per second regardless.

I'm just telling you what they said.

Go tell them what we said, then come back & tell us what they said (but don't tell them we told you to tell them).
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Old 09-10-2011, 12:44 AM - Thread Starter
 
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Well, trust me, I have seen many say incorrect information on thiss tie. Not saying it's the case this time, but certainly one has to look into thigns before knowing what's true as this site isn't any more immune to false information than anywhere else. The post a few above is itneresting if correct also, but thus far nobody else has said 240 sets are better.
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Old 09-10-2011, 12:16 PM - Thread Starter
 
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I should save it because you say so when only one other person in here said 240 has much of any advantage? Also if I ask for opinions what makes you think I have to take yours as if everyone agrees? Not everyone agres so I can't follow every opinion in here.

I was deciding between a 47 inch 240 and 55 inch 120. Now that I decided I definitely want 50+ inches I am throwing the 47 out the window and the 55 240 is crazily priced in comparison with the 120. So things have changed. I am still considering Sharps though, but I hate to go back down from 55 to 52 and if I wanted to go up to 60 that's a bit big. I think 55 is probably the best size, but Sharp doesn't have them.
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Old 09-10-2011, 03:36 PM
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Quote:
Originally Posted by 8mile13 View Post

And how does that work? 60 native frames and 50 artificial frames? There are 10 frames missing, the endresult should be 120, right?

And what about Motion Interpolation low, mid, high? Is this in all cases 50 artificial frames?

It's not 50 fake frames, it's 60. Every other frame is a fake one.

Think of it this way:

Set analyzes 1st and 2nd real frame and puts fake frame in between. It then takes 2nd real frame again and 3d real frame and inserts fake frame between and so on. So you have an equal number of real and fake frames--60 each every 60th of a second.

Low, mid, high, just makes the interpolation algorithm less or more aggressive.
The more interpolation taking place the less resolution loss there is during fast motion but the more fake the picture will look (more Soap Opera Effect).

Imho it's kinda academic because with all but the best HD sources overcompression artifacts are going to mess up the picture as much as or more than motion blur.

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Old 09-10-2011, 04:04 PM
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Quote:
Originally Posted by Steve S; View Post

It's not 50 fake frames, it's 60. Every other frame is a fake one.

Think of it this way:

Set analyzes 1st and 2nd real frame and puts fake frame in between. It then takes 2nd real frame again and 3d real frame and inserts fake frame between and so on. So you have an equal number of real and fake frames--60 each every 60th of a second.

Low, mid, high, just makes the interpolation algorithm less or more aggressive.
The more interpolation taking place the less resolution loss there is during fast motion but the more fake the picture will look (more Soap Opera Effect).

Imho it's kinda academic because with all but the best HD sources overcompression artifacts are going to mess up the picture as much as or more than motion blur.

I understand it now.


Lets just say * is a fake frame, i was counting like this:
1*2*3*4*5*6*7*8*9*10 =9*x 6=54*, i should have ended up with 59* since behind 10 another * starts.

so, there will be a fake frame first or after frame number 60 in order to get 60 fake frames:
*1*2*3*4*5*6*7*8*9*10
OR
51*52*53*54*55*56*57*58*59*60*

this way the TV mimics 120Hz, its not native 120Hz.
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Old 09-10-2011, 04:08 PM - Thread Starter
 
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On an aside, do any particular sets handle artifacts especially well? Is it only going to eb the several thousanddollar range sets? Man, artifacts are the most annoying thing imaginable and I wish they cared more about eliminating thsoe than such lame things as tv widths being abrely better than others. What's the difference in a 1 inch wide set and 2 inch wide one? Even ahnging them doesn't seem like enough difference to be willing to sacrifice picture for!

On topic, though, nobody has said whether they agree or disagree with the guy who stated that a 240 set automatically has better components making up the set itself.
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