Up until late 2007, there were a few high-end CRT and DLP displays that supported a 240Hz refresh. Now Samsung will bring to market an LCD flat panel HDTV with that specification:

http://www.businesswire.com/portal/site/home/news/sections/?ndmViewId=news_view&newsLang=en&newsId=20080513006839

I count myself among the admirers of the current 120Hz technology, which was acheived by driving the fastest available conventional LCD panels with "overdrive" technology panel driver circuitry. But this is a new process, claimed to be both inherently faster and inherently cheaper to manufacture than conventional LCD panels.

The better 120Hz displays are capable of delivering an occasional scene that has such utter clarity than one is tricked into believing that you are looking through a window of pure glass into another world. This is so convincing and so startling that many just cannot adjust to it - you'll find much discussion in various AVS threads about this topic.

I'm not one to fault a display for being "too real", and I've been enjoying my Samsung LN-T4669 120Hz display since December. I expect that the clarity that 240Hz brings may be just as dramatic as the 60Hz-to-120Hz difference is today - a new high water mark in realism.

The most encouraging thing about the new technology is that it does not depend upon technological advances to make the new panels cheaper - unlike OLEDs or other tatalizing technology that have frustratingly been just around the corner for years. Indeed, the new panels are already cheaper than conventional LCD panels, only a capital investment in a manufacturing facility for the new technology is needed. Samsung appears to be building this facility already and expects to ship 240Hz LCDs in 2011.

ya, too bad it isn't real. It's faking what Plasmas do naturally.

ya, too bad it isn't real. It's faking what Plasmas do naturally.

What would that be? You own a 60Hz plasma, and made an uninformed - and wrong - statement about 120Hz technology.

Plasma's do "have the look of film", if that is your objective. That is an intentionally unrealistic image that mimics the appearance of film in a theater, but with the added motion degradation of telecine motion judder (which most people do not notice, having watched 60Hz TVs their entire lives). But if you regularly go to a theater as I do, then you know that many many films incorporate extensive digital processing either as part of the special effects, or have a 100% digital intermediate stage which avoids a film edit in favor of a digital edit. The current theatrical film Iron Man is an example of one such - there is no film master, only a digital master, and therefore the best way to see it in a theater is to pick one with a digital projector. When that film is released on Blu-Ray, the best disk playback and the one that looks most like the digital theatrical playback would be a 24Hz Blu-Ray player driving a 120Hz display. 60Hz plasma displays don't come close to the quality of 120Hz LCDs when playing back modern digital films - although you can argue that they have advantages for 25+ year old 100% film movies.

Classic film buffs may indeed be better served by plasma displays. But for Blu-Ray playback of modern digital films, or ATSC television broadcasts, the best display is a 120Hz LCD.

The most encouraging thing about the new technology is that it does not depend upon technological advances to make the new panels cheaper - unlike OLEDs or other tatalizing technology that have frustratingly been just around the corner for years. Indeed, the new panels are already cheaper than conventional LCD panels, only a capital investment in a manufacturing facility for the new technology is needed. Samsung appears to be building this facility already and expects to ship 240Hz LCDs in 2011.

This is BS. The technology is ready, it's better and it's cheaper, but we won't see it in three years. Yes... of course.

If the technology were ready, were better and were cheaper, we wouldn't see a non-240Hz samsung TV in 2009.

What I read on those lines is that the technology is better, the yields are crap, and the projected costs without the current manufacturing issues, are optimistic enough to make a press release.


Sooo... like with OLED, I don't give a damn.

I agree.....the last paragraph says not to really expect these until 2011.....

By then, something bigger and better will come along.

I'm not getting too worked up about this news.

FYI it takes 3+ years to plan, finance, and build a major capital plant to manufacture a new technology. Don't be fooled by the fact that both share the moniker "LCD" - that's because both contain nematic liquid crystals, it does not imply any production machinery used on the present LCD lines apply to the new panels.

The real problem with OLEDs is that we lack a comprehensive semiconductor model of these devices - therefore all production parameters are determined by purely empirical testing. Surprises and failures to scale up panel sizes are common. All types of LCD displays by contrast lack the theoretical complexity of semiconductor devices - they are governed by Chemistry and Physics far easier to understand than the Quantum Physics used to model semiconductors.

The 120 Hz display allows each frame of 24 fps film to get equal time on the screen, compared with 60 Hz that requires 3/60'ths (1/20'th) second for some frames and 2/60'ths (1/30'th) second for some frames, thus reducing judder ...

... if the TV processes the incoming video signal appropriately.

What does 240 Hz offer over 120 Hz on LCD displays?

The 120HZ thing was originally created to solve motion blur not judder, and I think people are confusing refresh rate with frame rate.

The "real life" look people are associating with 120HZ is not due to the faster refresh but due to added frames that are created by interpolating. This is causing movies to have more FRAMES per second.

In fact most 120HZ LCD do NOT do 5:5 pulldown (each frame of a film displayed 5 times) but, when turning off the motion enhancers, instead do a simple doubling of 60hz that produces a 4:6 pull down. Those that do black frame insertions probably have even weirder pulldowns. I think some of the newer models of LCD do 5:5 pulldown but some newer Plasma’s can do straight multiples of 24 also.

As for digital films being different than standard file, both are at a native 24 frames so I don’t follow the logic that messing with the look and feel of film is any different in either case.

Regardless, if you like this effect, great leave it on. I find it nauseating to look at and it also seems to mess up 60HZ video.

Plasma's do "have the look of film", if that is your objective. That is an intentionally unrealistic image that mimics the appearance of film in a theater, but with the added motion degradation of telecine motion judder
Excuse me? My 3 year old plasma is perfectly able to showing 23.976 movie content without telecine motion judder. And many current plasmas do, too. E.g. Pioneer Kuros show 24fps content in 72Hz. Furthermore there are 120Hz LCDs which show 24fps content as 2x60Hz (with 3:2 motion judder).

So stop confusing people, please.

There are LCDs which are able to show 24p content without 3:2 judder. And there are plasmas which are able to do the same. There are LCDs which are not able to do that. And there are plasmas which are not able to do it. This has nothing to do with LCD vs. plasma, as you make it sound.

-snip-
As for digital films being different than standard file, both are at a native 24 frames so I don’t follow the logic that messing with the look and feel of film is any different in either case.
-snip-


The frame rate in this case is not related to what I am talking about.

A film projector uses a slotted wheel in front of the projection lamp to flash a pulse of light through the film frame. In fact although you are correct that the film is 24fps, modern projectors double flash each frame to reduce flicker, there are 48 flashes of light per second.

Digital projectors use a sample-and-hold principle, where the projection lamp is continuously illuminated and either shines through an image panel (LCD technology) or reflects off a mirror assembly (DLP technology). The large-venue theatrical type projectors work the same way (sample-and-hold) but many increase brightness by using three seperate imaging panels (3-chip LCD) or three seperate mirror panels (3-chip DLP), seperating the primary colors to increase brightness.

A Plasma flat panel display mudulates the electric current through the pixels to produce flases of light - like a film projector. The resulting panel image has the subliminal flicker of film, and many prefer this display for film source material. Because we all grew up watching TVs that have a fixed 60Hz refresh, many are not sensitized to the motion judder that results from the telecine process that displays 24fps film on a 60Hz video display.

The LCD flat panel is a sample-and-hold display, it does not depend upon flashes of light. It is a superior means of reproducing what you see from a digital master. Those displays that offer 120Hz refresh solve the motion judder, and frame interpolation adds clarity - and 240Hz will IMHO produce even clearer pictures, with more of that "realer than real", 3D popping images that are so very clear - as with a digital theater projector showing digital source video.

But in fact to save money and time in editing, or to post-process filmed images to change color balance or add fake film grain or for dozens of other reasons, most modern films go through a complete intermediate digital master, and can be distributed either on film or as digital files. If there is a digital master, then a digital projector is the best theatrical presentation - except it does not have the flashing look of film. If you doubt this, then compare the current film Iron Man which is being distributed on both film and digital - the digital version looks clearer, sharper, and has more saturated color - but lacks the classic "look" of film.

In fact it is getting rare to have a modern film produced without a digital intermediate process - with optical versus digital special effects. The modern movies look more like they do in the theater on an LCD display than a plasma display.

The LCD flat panel is a sample-and-hold display, it does not depend upon flashes of light. It is a superior means of reproducing what you see from a digital master.
Although I agree with most of your technical explanations (sample-and-hold etc), I do not agree that sample-and-hold is a superior means of reproducing a digital master. Actually LCD (and SXRD/D-ILA) producers are trying to find ways to get rid of the sample-and-hold effect by using various techniques. E.g. the current top of the line Sony front projector offers both interpolated intermediate images and inserted dark frames. The inserted dark frames simulate what theater projectors (and plasmas!) do, namely "flashes of light", as you call it. If you read the Sony front projector thread you'll notice that most people prefer to have the intermediate image interpolation turned completely off or nearly off for movie content, but most like the dark frame insertion. So in other words: Most people prefer the flashes-of-light way of watching movies instead of the interpolated-intermedia-images way. So what is superior or not superior might be a matter of taste. You prefer the interpolation stuff, others prefer "flashes of light". I don't think you can call one solution superior if the majority of people prefer the other solution.

The modern movies look more like they do in the theater on an LCD display than a plasma display.
I don't agree at all. Most theaters still use film based projectors which shutter (each frame shown twice). And looks much more like what a plasma display is doing. Those theaters using digital projectors likely have the sample-and-hold-effect (motion smear). Current digital cinema projectors to my best knowledge don't use technology similar to what 120Hz LCD displays do. They neither use dark frame insertion nor interpolated intermediate images. I think digital projection in cinema will improve in the future. Likely dark frame insertion will be introduced in digital cinema projectors sooner or later. That again will look more like plasma than like 120Hz LCD with interpolated intermediate images.

Hmm... Interesting. Samsung went through a whole deal of trouble trying to perfect the 120Hz standard with AMP in their 6/7 Series LCDs this year, and now they feel that isn't enough. I saw how the technology works, and it looked better than any LCDs I've seen before, and now it's gonna wind up being obsolete in another 3 years from now. Jeez...

The 120 Hz display allows each frame of 24 fps film to get equal time on the screen, compared with 60 Hz that requires 3/60'ths (1/20'th) second for some frames and 2/60'ths (1/30'th) second for some frames, thus reducing judder ...

... if the TV processes the incoming video signal appropriately.

What does 240 Hz offer over 120 Hz on LCD displays?

Twice as many Hz as the competitors. I figured that would be obvious! ;)

--Mav

Although I agree with most of your technical explanations (sample-and-hold etc), I do not agree that sample-and-hold is a superior means of reproducing a digital master. Actually LCD (and SXRD/D-ILA) producers are trying to find ways to get rid of the sample-and-hold effect by using various techniques. E.g. the current top of the line Sony front projector offers both interpolated intermediate images and inserted dark frames. The inserted dark frames simulate what theater projectors (and plasmas!) do, namely "flashes of light", as you call it. If you read the Sony front projector thread you'll notice that most people prefer to have the intermediate image interpolation turned completely off or nearly off for movie content, but most like the dark frame insertion. So in other words: Most people prefer the flashes-of-light way of watching movies instead of the interpolated-intermedia-images way. So what is superior or not superior might be a matter of taste. You prefer the interpolation stuff, others prefer "flashes of light". I don't think you can call one solution superior if the majority of people prefer the other solution.


I don't agree at all. Most theaters still use film based projectors which shutter (each frame shown twice). And looks much more like what a plasma display is doing. Those theaters using digital projectors likely have the sample-and-hold-effect (motion smear). Current digital cinema projectors to my best knowledge don't use technology similar to what 120Hz LCD displays do. They neither use dark frame insertion nor interpolated intermediate images. I think digital projection in cinema will improve in the future. Likely dark frame insertion will be introduced in digital cinema projectors sooner or later. That again will look more like plasma than like 120Hz LCD with interpolated intermediate images.

It would be interesting to find out what digital projectors do to remove the ill effects of Sample and Hold. It would make sense that sample and hold, without a blackframe insertion or extra frames to create more "flashes of light", is what is causing ghosting on LCDs. Though part of the effect is due to hiw our brains blur motion naturally(I believe).

When I see DLP projects used in the theaters they seem to exhibit digital noise and have less dynamic range than classic projectors, but I have not noticed any ghosting.

Twice as many Hz as the competitors. I figured that would be obvious! ;)

--Mav

Ah, but the Panasonics have 480hz!

WTF? :confused:

This is getting to be as bad a contrast ratios. Much as buying off the Internet is cheaper, I wonder if it has a lot to do with this war of numbers...

Couple years ago, when 120Hz was still in the research stage, I posted about this 240Hz. Essentially researchers found that even if 120Hz with full interpolation is used the motion resolution can never match that of a CRT. They found that human perception (HVS) of blur will optimally be reduced with 240Hz.

Y. Kuroki, T. Nishi, S. Kobayashi, H. Oyaizu, and S. Yoshimura

ABSTRACT:The ideal frame rate for the highest motion-image quality with respect to blur and jerkiness is presented. In order to determine the requirements for avoiding these impairments, motion images from a high-speed camera and computer graphics were combined with a high-speed display to perform a psychophysical evaluation. The camera, operating at 1000 fps, and image processing were used to simulate various frame rates and shutter speeds, and a 480-Hz CRT display was used to present motion images simulating various frame rates and time characteristics of the display. Subjects were asked to evaluate the difference in quality between motion images at various frame rates. A frame rate of 480 fps was chosen to be an appropriate reference frame rate that, as a first estimation, enables coverage up to the human-dynamic-resolution (HDR) limit based on another experiment using real moving charts. The results show that a frame rate of 120 fps provides good improvement compared to that of 60 fps, and that the maximum improvement beyond which evaluation is saturated is found at about 240 fps for representative standard-resolution natural images. ©2007 Society for Information Display

Ah, but the Panasonics have 480hz!

WTF? :confused:

This is getting to be as bad a contrast ratios. Much as buying off the Internet is cheaper, I wonder if it has a lot to do with this war of numbers...Panasonic is playing the marketing game. 480Hz refers to the sub-frame rate, not the frame rate. In the Panasonic it takes 8 sub-frames to compose 1 frame. 8x60 = 480

The frame rate in this case is not related to what I am talking about.

A film projector uses a slotted wheel in front of the projection lamp to flash a pulse of light through the film frame. In fact although you are correct that the film is 24fps, modern projectors double flash each frame to reduce flicker, there are 48 flashes of light per second.

Digital projectors use a sample-and-hold principle, where the projection lamp is continuously illuminated and either shines through an image panel (LCD technology) or reflects off a mirror assembly (DLP technology). The large-venue theatrical type projectors work the same way (sample-and-hold) but many increase brightness by using three seperate imaging panels (3-chip LCD) or three seperate mirror panels (3-chip DLP), seperating the primary colors to increase brightness.

A Plasma flat panel display mudulates the electric current through the pixels to produce flases of light - like a film projector. The resulting panel image has the subliminal flicker of film, and many prefer this display for film source material. Because we all grew up watching TVs that have a fixed 60Hz refresh, many are not sensitized to the motion judder that results from the telecine process that displays 24fps film on a 60Hz video display.

The LCD flat panel is a sample-and-hold display, it does not depend upon flashes of light. It is a superior means of reproducing what you see from a digital master. Those displays that offer 120Hz refresh solve the motion judder, and frame interpolation adds clarity - and 240Hz will IMHO produce even clearer pictures, with more of that "realer than real", 3D popping images that are so very clear - as with a digital theater projector showing digital source video.

But in fact to save money and time in editing, or to post-process filmed images to change color balance or add fake film grain or for dozens of other reasons, most modern films go through a complete intermediate digital master, and can be distributed either on film or as digital files. If there is a digital master, then a digital projector is the best theatrical presentation - except it does not have the flashing look of film. If you doubt this, then compare the current film Iron Man which is being distributed on both film and digital - the digital version looks clearer, sharper, and has more saturated color - but lacks the classic "look" of film.

In fact it is getting rare to have a modern film produced without a digital intermediate process - with optical versus digital special effects. The modern movies look more like they do in the theater on an LCD display than a plasma display.

I don't think whether the Film is capture digitally or via analog film has much to do with what the temporal recording of the frames.

Someone who is involved in the film making process may want to wade in, but when a frame of film is captured it is exposed multiple times to induce Motion Blur into the frame. That blur is necessary otherwise the film, whether digital or not, would look like a strobe light at 24 fps. However too much blur, leaving the frame exposed for a full 1/24 of a second, would also become noticeable at only 24 fps; ghosting would be pronounced. Consequently each frame is representing something less than 1/24 of a second.

Therefore the "hold and sample" of a display would be as unnatural to the frame whether it was captured with digital means or not. LCD’s by the way do have some flicker, the backlight does pulse on and off at a rate greater than the refresh rate. Without those "flashes of light" LCD's ghosting issues would be MUCH worse. 120HZ with black frame insertion are another method to introduce "flicker".

I do admit I am a plasma enthusiast, but as LED backlight and local dimming become more mature I am starting to like LCD's also. I just don't like technology that adds something that wasn't there in the source (motion enhancers) and I still don't agree that LCD's have a natural advantage when displaying film.

It would be interesting to find out what digital projectors do to remove the ill effects of Sample and Hold. It would make sense that sample and hold, without a blackframe insertion or extra frames to create more "flashes of light", is what is causing ghosting on LCDs.
The sample-and-hold effect mainly produces motion blur in our brain. I don't think it causes ghosting.

When I see DLP projects used in the theaters they seem to exhibit digital noise and have less dynamic range than classic projectors, but I have not noticed any ghosting.
I think DLP breaks up the image similar to how plasma does it due to the way DLP works (mirrors and color wheels etc).

Panasonic is playing the marketing game. 480Hz refers to the sub-frame rate, not the frame rate. In the Panasonic it takes 8 sub-frames to compose 1 frame. 8x60 = 480

Yeah I know, I was just furthering the point.

You should try explaining that to a customer... *exasperated*

Furthermore there are 120Hz LCDs which show 24fps content as 2x60Hz (with 3:2 motion judder).

Yeah, but the current 120hz people generally talk about (Samsung and Sony) use proper 5:5 rather than 2x60.



The main confusion about 120hz I've found, stems from Samsung, who named the Motion Enhancer "Automotion Plus 120hz" and the first TV's to REALLY show a difference to the average consumers were the Samsung's and Sony's with Motion Enhancer.

Couple years ago, when 120Hz was still in the research stage, I posted about this 240Hz. Essentially researchers found that even if 120Hz with full interpolation is used the motion resolution can never match that of a CRT. They found that human perception (HVS) of blur will optimally be reduced with 240Hz.
Thanks! Good and interesting information... :)

Yeah, but the current 120hz people generally talk about (Samsung and Sony) use proper 5:5 rather than 2x60.
Agreed. My point just was that having 3:2 motion judder has nothing to do with LCD vs. plasma. There are some LCDs with motion judder when doing 24p playback and some without. And there are some plasmas with motion judder and some without.

Lest anybody miss this point, any frames that originate in the digital domain - meaning 100% of animated features and most scenes in a digital effects laden film like Iron Man, never had an analog film frame original. They were created by digital effects artists on sample-and-hold displays, and IMHO best displayed on sample-and-hold digital projectors.

In spite of the continuing popularity of the film projector - a media that was essentially defined by Thomas Edison in the 19th century - we can do better today. I hate to bring up a topic so likely to cause prolonged discussion, but very likely most of you have seen a digital presentation of something - even if it was as far back as Star Wars Episodes 1-3.

Virtually every audience member who has a chance to compare the film and digital theatrical presentations of a digitally-mastered film prefers the digital version. If nothing else, the digital master is one entire generation copy newer, and the unique advantage of digital processing is that copying does not degrade the image. But if a digitally mastered movie gets distributed on film, it gets two generations of optical processing (produuction negative and distribution positive) added.

When you utilize the best available media (Blu-Ray and HD-DVD) and view a film that either originates as 100% digital (like an animated film) or just went through an intermediate digital master (as did such diverse works as O Brother Where Art Thou?), then you will almost certainly conclude (as I have) that the sample-and-hold LCD is a better representation of what you see in the theater.

I don't disagree with the point that most theaters utilize film distribution prints, by the way. But here in Silicon Valley there are numerous digital projectors, and I patronize those theaters and select the digital presentations wherever possible, to get the best quality presentation of a digitally mastered movie. Then when I later revisit that movie at home, I select a Blu-Ray disk (or HD-DVD) and an LCD flat panel display (or my LCD front projector) as the display of choice - versus trying to mimic the appearance of film using a plasma display, when the source material never was a film.

It's one of those technological paradigm shifts. More of what you see on screen today originates in a digital studio than in a film shoot. I want the best presentation I can get - the one that most resembles real life, not the one that most resembles Thomas Edisons's (admittedly wonderfull) 19th century moving picture display. Therefore I'm ready to embrace sample-and-hold displays, frame interpolation, and 120Hz or 240Hz refresh.

I realize not everyone will agree - just as there are those who persist in clinging to vinyl records and vacuum tube amplifiers, for pretty much the same reasons - the look and sound of familiarity is comforting.

Curiosity question - does anyone know how the new DLP projectors work? I don't think they run film, but I saw 'There Will Be Blood' at a DLP theater and it was definitely film-like. I suppose it could be that the TWBB copy they got was film...

I will say that I saw Iron Man at the same DLP theater (definitely digital) and later saw it in a non-DLP (not sure if it was a digital projector or a film copy though) and there was large difference in the colour and motion quality as well as the black levels.

It,s hard to answer your question because you were not specific about what you meant by "film like". However, O Brother, Where Art Thou? was filmed, then digitized for editing and post-processing. To quote Wikipedia about "The Look of the Film":

One of the notable features of the film is its use of digital color correction to give the film a sepia tinted look.
“ Ethan and Joel favored a dry, dusty Delta look with golden sunsets. They wanted it to look like an old, hand-tinted picture with the intensity of colors dictated by the scene, and natural skin tones that were all shades of the rainbow. ”
—cinematographer Roger Deakins

This was the fifth film on which the Coen Brothers had worked that was slated to be shot in Mississippi at a time of year when the foliage, grass, trees and bushes would be lush green. Filmed near locations in Canton, MS, Florence, SC and Wardville, LA. After shooting tests, including film by-pack and bleach bypass techniques, Deakins suggested digital mastering be used. The cinematographer subsequently spent eight weeks fine tuning the look, mainly de-saturating green and timing the digital files. This made it the first feature film to be entirely color corrected by digital means, narrowly beating Nick Park's Chicken Run.

Deakins was recognized with both Oscar and ASC Outstanding Achievement Award nominations for his work on the film.

At a guess, what you are referring to as "the look of film" is the 24fps frame rate, which in fact is used for BOTH digital and film projection - but only in dark theaters. But flicker will be noticed when 24fps source is displayed in a room with partial or full illumination from 60Hz artificial lighting - therefore the flicker-reduction requires that one synchronize the display refresh with the 60Hz power - a 60Hz or 120Hz or 240Hz refresh. 60Hz displays are as old as Black and White television from the 1930's.

To answer your specific question, a DLP 3-chip projector shines focused light from a lamp through 3 primary color filters, then the beams reflect off an array of micro-mirrors which tilt to scatter the beam. The relative amount of on/off time varies pixel brightness, and the exact mix of the three primary colors sets the color of each pixel. The three color beams are combined again in an optical convergence assembly, then get re-focused on the screen, usually with an anamorphic lens.

It's one of those technological paradigm shifts. More of what you see on screen today originates in a digital studio than in a film shoot. I want the best presentation I can get - the one that most resembles real life, not the one that most resembles Thomas Edisons's (admittedly wonderfull) 19th century moving picture display. Therefore I'm ready to embrace sample-and-hold displays, frame interpolation, and 120Hz or 240Hz refresh.

I realize not everyone will agree - just as there are those who persist in clinging to vinyl records and vacuum tube amplifiers, for pretty much the same reasons - the look and sound of familiarity is comforting.

FYI, what if the people making the digitally movies were using CRT computer monitors? Then wouldn’t CRT’s be best used to view the movies?:confused:

Kdding aside, I think you are missing the crutch of the counter argument. Film is 24 frames per second, each representing 1/48 of second blurred to achieve a good mix of flicker and motion blur. Whether the frame was created digitally or not, it MUST have these characteristics or it will not look good at 24 fps.

If you want REAL LIFE then you want more FPS - the technologies used to diplay film in the home do NOT do this except Frame Interpolation ONLY.

120Hz and 240Hz refreshes, and black frame insertions, are currently used to fix the SHORTCOMINGS of "sample-and-hold" LCD's. Lest you forget Plasmas and CRT's use phosphor that fade fairly slowly to achieve the same result your "sample and hold" displays do with out the side affects. Hence no 120HZ plasma are necessary. Those that do display Film properly do it at 48HZ or 72HZ.

I hear you on more FPS, but 24 fps is an artistic choice that film makers use. I have heard in the past that higher frames rates were tried but people experienced motion sickness and so that was abandoned.

As for more FPS, native 720p60 is the highest Frame Rate consumer technology currently out there. All others give 24 (film), 30 (some HD), or 60 Fields (SD and some HD). 1080p60 from a blu-ray is still only 24 frames per second - with the whole 2:3 pulldown thing. If you want more FPS you either need a source that gives it (it is not likely to happen soon and I doubt your TV would accept the signal) or you create it on the fly (frame interpolation).

Like I said earlier refresh rate is different than frame rate. Without Frame interpolation the frame rate of film is still 24fps regardless if you refresh at 48,60, 120, or 240 times per second, or whether it was created digitally OR not.

If you love Frame interpolation, fine, leave it on. I for one dislike it for film and it introduces strange artifacts for video (TBE). If some new technology comes along that is INTENDED to be 120FPS then you, my friend, are sitting pretty. Until then I prefer to watch material the way it was meant to be seen - without all the extra garbage.

-D
"When a group smart people have the same information, they will have the same conclusions. If they don't, the information is bad or they weren't that smart to begin with."

It,s hard to answer your question because you were not specific about what you meant by "film like". However, O Brother, Where Art Thou? was filmed, then digitized for editing and post-processing. To quote Wikipedia about "The Look of the Film":

One of the notable features of the film is its use of digital color correction to give the film a sepia tinted look.
“ Ethan and Joel favored a dry, dusty Delta look with golden sunsets. They wanted it to look like an old, hand-tinted picture with the intensity of colors dictated by the scene, and natural skin tones that were all shades of the rainbow. ”
—cinematographer Roger Deakins

This was the fifth film on which the Coen Brothers had worked that was slated to be shot in Mississippi at a time of year when the foliage, grass, trees and bushes would be lush green. Filmed near locations in Canton, MS, Florence, SC and Wardville, LA. After shooting tests, including film by-pack and bleach bypass techniques, Deakins suggested digital mastering be used. The cinematographer subsequently spent eight weeks fine tuning the look, mainly de-saturating green and timing the digital files. This made it the first feature film to be entirely color corrected by digital means, narrowly beating Nick Park's Chicken Run.

Deakins was recognized with both Oscar and ASC Outstanding Achievement Award nominations for his work on the film.

At a guess, what you are referring to as "the look of film" is the 24fps frame rate, which in fact is used for BOTH digital and film projection - but only in dark theaters. But flicker will be noticed when 24fps source is displayed in a room with partial or full illumination from 60Hz artificial lighting - therefore the flicker-reduction requires that one synchronize the display refresh with the 60Hz power - a 60Hz or 120Hz or 240Hz refresh. 60Hz displays are as old as Black and White television from the 1930's.

To answer your specific question, a DLP 3-chip projector shines focused light from a lamp through 3 primary color filters, then the beams reflect off an array of micro-mirrors which tilt to scatter the beam. The relative amount of on/off time varies pixel brightness, and the exact mix of the three primary colors sets the color of each pixel. The three color beams are combined again in an optical convergence assembly, then get re-focused on the screen, usually with an anamorphic lens.

I realize I am questioning everything you post but bear with me :)

How is it that 60hz powered lighting causes re-fresh rates not multples of 60hz to show flicker? Isn't flicker more a symptom of how the brain perceives images and the native frame rate/ refresh rate / exposure time of the material?

I use my 19inch CRT monitor at 85hz refresh and I don't see ANY flicker. Even when I use it at night with Incandescent lights on in the room. If it gets set to 60hz then I see flicker galore. With your reasoning it should be the other way around. Or maybe I just don't get it...:D

-D
"When a group smart people have the same information, they will have the same conclusions. If they don't, then the information is bad or they weren't that smart to begin with."

I understand your argument, but I refer you to my last message, because video displays are intended for use in lighted or partially lighted rooms, and therefore are refreshed at some multiple of 60Hz to avoid visible flicker. If you have ever viewed a computer CRT that didn't quite sync with the 60Hz lighting, then you have seen flicker, and it goes beyond nausea, flickering computer displays have induced epileptic siezures in susceptable users.

The 60Hz display is what you have viewed for your entire life with TV, and it has a familiar look, but the 60Hz refresh causes a variety of motion flaws, you can't appreciate how serious until they are gone. I have been running my front projector at 72Hz for film and 60Hz for video for years, I could not stand the judder. The 120Hz is great - and I view movies at 24Hz with frame interpoolation on High, because it smooths motion and eliminates artifacts.

I can see the TBE you speak of, but only from 1080i broadcast source. I don't see it on disk media at 24Hz => 120Hz.

Edit: we are responding to one another's posts too quickly to keep in sync, it's confusing. But the flicker originates from a phenomenon known as "hetrodyning". Flicker is visible in a theater when the door is opened and light shines on the screen, at about 12Hz, the "difference frequency" between the 48Hz double-flashed film frames and the 60Hz lighting. A similar 12Hz flicker is seen when a 72Hz screen refresh is used on a computer display in a room lighted at 60Hz - and the rapid 12Hz flicker is in the frequency range for epileptic siezures.

As for the 48Hz and 72Hz plasma displays you mention - they have the same liability and the same potential to induce siezures as do computer displays - perhaps more so because of screen size and brightness. Fortunately many people use them in totally darkened "home theater" environments where flicker won't happen. But I would not own such a display - I never want one of my guests spazming out from heterodyne flicker, if a light gets turned on.

This is great. Finally, there will be no more motion blur on LCDs. I've been waiting for 240Hz LCDs for a long time (FED prototypes can do 240Hz already). This technology can't come soon enough. By the time this is implemented in commercial sets, LED BLUs with local dimming will have matured a lot and the cost will probably fall down a bit too.

One final comment - several film systems have been developed over the years that utilize 48fps or faster frame rates. These share two characteristics:

1) Filmmakers love the realer-than-real look of the resulting images, the lack of jitter (from frame stabilization) and the lack of flicker - because it replaces the legacy 19th Century "look of film" that Thomas Edison established.

2) All such improved displays have been commercial flops, due to the installed base of 24fps 35mm projectors - the expense of migration was too great. These ultra-realistic systems are now used only in simulators in theme parks and military training facilities.

I'm wondering if this would be more useful for SD DVDs over a Blu-ray, since SD DVDs do tend to be a little more "film looking" as opposed to native high-definition movies.

Lest anybody miss this point, any frames that originate in the digital domain - meaning 100% of animated features and most scenes in a digital effects laden film like Iron Man, never had an analog film frame original. They were created by digital effects artists on sample-and-hold displays, and IMHO best displayed on sample-and-hold digital projectors.
I'm sorry. But the big majority of the movies out there do still originate from film. Sure, there are a lot of movies these days which are "enhanced" by computer generated effects. But that doesn't change the fact that the origin of the movie is usually still film. Furthermore: Do you really want to make your decision which display to use based on the computer generated effects? That moves the importance of those effects to whole new level. IMHO the effects are not the most important thing in the movie. Maybe you feel different? Do you watch movies only because of the digital effects?

Virtually every audience member who has a chance to compare the film and digital theatrical presentations of a digitally-mastered film prefers the digital version. If nothing else, the digital master is one entire generation copy newer, and the unique advantage of digital processing is that copying does not degrade the image. But if a digitally mastered movie gets distributed on film, it gets two generations of optical processing (produuction negative and distribution positive) added.
Sure. I can agree with that. But nothing of this has anything to do with whether sample-and-hold is better than "flashes of light" or not. It's all only about analog vs digital storage of the pixels.

When you utilize the best available media (Blu-Ray and HD-DVD) and view a film that either originates as 100% digital (like an animated film) or just went through an intermediate digital master (as did such diverse works as O Brother Where Art Thou?), then you will almost certainly conclude (as I have) that the sample-and-hold LCD is a better representation of what you see in the theater.
I'm sorry, but I don't agree at all. And you are by far in the minority with your conclusion. Furthermore: What does an intermediate digital master have to do with whether sample-and-hold is better or worse? *Nothing*.

I realize not everyone will agree
Actually from what I've read in the forums most home theater enthusiasts disagree with you.

just as there are those who persist in clinging to vinyl records and vacuum tube amplifiers, for pretty much the same reasons - the look and sound of familiarity is comforting.
And you belong to those who like new technologies just because they are new? Regardless of whether they are better or not? I sure agree with you that digital storage of movies is much better than having a chain of analog copies. But having digital storage does not have anything to do with whether sample-and-hold is a good idea or not. Tell me: Why is Sony in the top of the class projector offer a functionality which simulates the cinema shutter? And why do most people who own the Sony projector like this feature a lot and think it improves the image quality? I'll tell you: Because sample-and-hold sucks big time for video display.

At a guess, what you are referring to as "the look of film" is the 24fps frame rate, which in fact is used for BOTH digital and film projection - but only in dark theaters. But flicker will be noticed when 24fps source is displayed in a room with partial or full illumination from 60Hz artificial lighting - therefore the flicker-reduction requires that one synchronize the display refresh with the 60Hz power - a 60Hz or 120Hz or 240Hz refresh. 60Hz displays are as old as Black and White television from the 1930's.
Gary, the flicker has nothing to do with artificial lighting. You don't have to synchronize the display refresh with 60Hz. Refreshing with 72Hz fully solves any flickering problem. And that is what a good plasma (e.g. Pioneer Kuro) is doing. Have you ever heard a Kuro owner complain about flickering when watching a Blu-Ray?

I understand your argument, but I refer you to my last message, because video displays are intended for use in lighted or partially lighted rooms, and therefore are refreshed at some multiple of 60Hz to avoid visible flicker. If you have ever viewed a computer CRT that didn't quite sync with the 60Hz lighting, then you have seen flicker
That's absolute nonsense. Actually CRTs at 60Hz still flicker slightly. It is generally recommended to drive CRTs with at least 72Hz to get fully rid of flickering. A quick google search will provide thousands of backup links for what I'm saying. Just the first 2:

http://www.devhardware.com/c/a/Video-Cards/Video-Hardware-Part-2/3/

"A refresh rate that is too low causes CRT screens to flicker, contributing to eyestrain. The higher the refresh rate you use with a CRT display, the better for your eyes and your comfort during long sessions at the computer."

http://en.wikipedia.org/wiki/Refresh_rate

"On CRT displays, increasing the refresh rate decreases flickering, thereby reducing eye strain."
"On smaller CRT monitors (~<14") few people notice any discomfort below 60–72 Hz. On larger CRT monitors (~>17") most people would experience mild discomfort unless the refresh is set to a more comfortable 85 Hz or higher. 100 Hz is comfortable for almost any size."

But the flicker originates from a phenomenon known as "hetrodyning". Flicker is visible in a theater when the door is opened and light shines on the screen, at about 12Hz, the "difference frequency" between the 48Hz double-flashed film frames and the 60Hz lighting. A similar 12Hz flicker is seen when a 72Hz screen refresh is used on a computer display in a room lighted at 60Hz - and the rapid 12Hz flicker is in the frequency range for epileptic siezures.
So we Europeans are doomed? We have no way to watch Blu-Ray movies without flickering? Remember, Blu-Rays are 23.976 here in Europe. But power frequency is 50Hz here.

The 120Hz is great - and I view movies at 24Hz with frame interpoolation on High, because it smooths motion and eliminates artifacts.
It smoothens the motion, that's right. But actually the current algorithms introduce new artifacts on their own. Reading the forums here it seems to me that most home theater enthusiasts dislike these frame interpolation algorithms.

One final comment - several film systems have been developed over the years that utilize 48fps or faster frame rates. These share two characteristics:

1) Filmmakers love the realer-than-real look of the resulting images, the lack of jitter (from frame stabilization) and the lack of flicker - because it replaces the legacy 19th Century "look of film" that Thomas Edison established.
I'd like to have 48fps, too. But please TRUE 48fps and not frames calculated by a funny algorithm which doesn't always get things right.

Furthermore: Even if we had 48fps that would still not have anything to do with whether sample-and-hold technology is a good solution for video playback or not. Actually even with 48fps a "flashes of light" technology would still be better for display than a sample-and-hold type display.

You seem to have missed the point that the DLP and LCD theatrical projectors that are today gradually replacing 35mm film are sample-and-hold displays. Flashing 35mm frames are the legacy of 19th Century Edison-type film projectors. The theatrical future is digital projection, and YES it looks different, and when given the choice between film and digital, the typical audience prefers digital by a large margin.

You further missed one point which was even the economics of film editing and post-processing today mandate that film frames from a live shoot be converted to a digital master. Another powerfull motive is that digital processing is much faster than optical, and gets your film to market months faster. If an intermediate digital master was used, the digital files transferred to the theater are bit-perfect representations of the final edit and two generations newer than a film distribution print. One reason that an audience prefers the digital version is it simply has significantly better image quality that the film distribution print.

My explanation of heterodyning was right on, and a small minority of the population can indeed be put into siezure by flashing lights or pulsing digital displays. The worst case in fact is a 60Hz display refresh on a computer display. Computer displays, unlike TVs, are not locked to the powerline frequency, the exact refresh rate is set by the video driver hardware based on a crystal oscillator, and therefore what is displayed as "60Hz" may be 58-62Hz and the very low difference frequency of 0-2Hz is extremely likely to introduce siezures. TVs are locked to the powerline frequency for a reason.

We are getting pretty far off topic here - you'd best spend some more time in researching the topic, and I have no doubt that you will come to understand the basis for digital display flicker.

But my fundamental point is that a technological change has overtaken the 19th Century technology of film. Now if you bother to sort out those movies that utilize a digital intermediate process step from those that are 100% analog including an optical edit and film distribution, you will notice that the digital projector is the best theatrical display. Now apply the same criteria to the home display.

LCD's have motion blur at 60 hz, they have motion blur at 120 hz, and they'll have it at 480 hz. There's much more to the equation than simply doubling operating frequencies and claiming that motion blur is solved.

Motion Blur, and you:
http://www.hdtvmagazine.com/articles/2008/01/lcd_specs_playing_with_your_eyes.php

You seem to have missed the point that the DLP and LCD theatrical projectors that are today gradually replacing 35mm film are sample-and-hold displays. Flashing 35mm frames are the legacy of 19th Century Edison-type film projectors. The theatrical future is digital projection, and YES it looks different, and when given the choice between film and digital, the typical audience prefers digital by a large margin.
You are making the mistake of thinking that "digital projection" automatically results in "sample-and-hold". It is true that many current digital projectors are sample-and-hold type. But it's by no means a must. As I already mentioned multiple times (you ignored it multiple times) Sony's top of the line projector offers a way to break up (or at least soften up) the sample-and-hold property by using dark frame insertion which simulates an impulse type display.

You further missed one point which was even the economics of film editing and post-processing today mandate that film frames from a live shoot be converted to a digital master. Another powerfull motive is that digital processing is much faster than optical, and gets your film to market months faster. If an intermediate digital master was used, the digital files transferred to the theater are bit-perfect representations of the final edit and two generations newer than a film distribution print. One reason that an audience prefers the digital version is it simply has significantly better image quality that the film distribution print.
And I already said that I totally agree with that. Have you read my reply at all??

Please understand that I'm not at all arguing against digital storage nor against digital projection. I'm all for both. I'm only arguing against sample-and-hold for movie playback. And I'm especially arguing against hailing sample-and-hold as a great thing. It's not. Not at all...

My explanation of heterodyning was right on, and a small minority of the population can indeed be put into siezure by flashing lights or pulsing digital displays. The worst case in fact is a 60Hz display refresh on a computer display. Computer displays, unlike TVs, are not locked to the powerline frequency, the exact refresh rate is set by the video driver hardware based on a crystal oscillator, and therefore what is displayed as "60Hz" may be 58-62Hz and the very low difference frequency of 0-2Hz is extremely likely to introduce siezures.
Buahahaha! "Extremely likely to introduce seizures"!! You are funny. It's strange that CRT computer monitors were not forbidden, since they are obviously so extremely dangerous.

We are getting pretty far off topic here - you'd best spend some more time in researching the topic, and I have no doubt that you will come to understand the basis for digital display flicker.
I've presented you with links which back up my claim that flickering is caused by too slow refresh rate. Now why don't you back up your claim (that any refresh rate other than a synced-to-powerline refresh rate produces flickering) with some links, too? And please don't come with special cases like 0.00001% of the population getting seizures. Show me a few links which explain that the refresh rate of an impulse type display must be linked to the powerline to avoid flickering, please.

You seem to be set in your opinions. Let me point you at just ONE little article on photosensitive epilepsy and how the commonest cause is flickering televisions and video games:

http://en.wikipedia.org/wiki/Photosensitive_epilepsy

...also note that darkened theaters are also environments where flicker induces such siezures.

I don't doubt that particular Sony uses BFI or Black Frame Insertion, the 2006-vintage of 120Hz LCD panels used this technique not for the reasons you quoted but because it boosted ANSI contrast measurements.

==> But note there are ZERO large-venue theatrical projectors with BFI, all are sample-and-hold designs. I can but believe that the Sony is an attempt to mimic a flashy projector and simulate the look of film. But one more time - that is the wrong goal to emulate the look of a modern digital movie in a digital theater.

Many of my friends initially felt as you did about my 120Hz display - right up until the 3rd or 4th movie, by which time they "got it", and two have upgraded to 120Hz displays and the other talks longingly of one.

It takes a period of time. I do think "paradigm shift" is an accurate way to describe it. Once you've made the adjustment, the flaws of 60Hz displays become glaringly obvious, and a film in a darkened theater has a quaint antique quality to it.

At 60hz DLP has a hold time of 8.3ms.

LCoS used to have a hold time of 16.7ms, but thanks to 120hz and Black Frame Insertion (BFI) they cut that down to 8.3ms.


But of course the lower amount of time either DLP or LCoS is holding a frame, the lower amount of light that is hitting the screen.



This is area where LED lighting can be a big win for DLP. Every year they get brighter and at some point they'll get bright enough allowing them to reduce the hold time further. The DLP chip is very fast, but light sources aren't bright enough to really take advantage of it. Well except laser. Then the difference between LED and Laser light comes down to heat dissipation.

240hz???
What will lcd do next to try to achieve what Plasma achieves naturally??
It has already been proven that 120hz does not eliminate the mortion problems inherit with LCD technology. It does good at reducing judder but still there is motion problems with LCD.
Also, 120hz causes serious artifacts that look like clear vapors coming of of people in movies. I really hated that.

With plasma all of these goofy tricks and add-ons are not nessesary. not to mention better black levels,

You seem to be set in your opinions. Let me point you at just ONE little article on photosensitive epilepsy and how the commonest cause is flickering televisions and video games:

http://en.wikipedia.org/wiki/Photosensitive_epilepsy
Good link, thanks. It backs up my claim and not yours. For one this article sais that it's about 2 people out of 10,000. Furthermore I found not the slightest hint in that article that the refresh rate of a display needs to be synced to the powerline frequency. Actually the article explicitly states:

"Modern digital television sets that cannot be maladjusted in this way and refresh the image on the screen at very high speed present less of a risk than older television sets."

This clearly proves my point that the refresh rate must be high enough to avoid flickering and that there's no correlation to the frequency of the powerline at all. So e.g. 72Hz is better than 60Hz.

I don't doubt that particular Sony uses BFI or Black Frame Insertion, the 2006-vintage of 120Hz LCD panels used this technique not for the reasons you quoted but because it boosted ANSI contrast measurements.
No, the primary reason is to get rid of the sample-and-hold effect to reduce motion blur. When Sony demoed their top of the line projector their main advertising argument was reduced motion blur. See here for a Sony demo report which clearly states that the purpose of the dark frame insertion is to increase detail level during motion. Contrast number were not even mentioned or advertized in that demo:

http://www.avsforum.com/avs-vb/showthread.php?t=880615

==> But note there are ZERO large-venue theatrical projectors with BFI, all are sample-and-hold designs.
See Brimstone-1's response. DLP is not fully sample-and-hold. Furthermore dark frame insertion is a rather new technology and needs fast panels and very bright light sources. I'd rather guess that theatrical projectors will sooner or later also get dark frame insertion technology. But for now they just can't afford to use this technology because theatrical projectors need a whole lot of light output and cannot afford wasting any light on doing dark frame insertion. They do have some motion blur as a consequence.

I can but believe that the Sony is an attempt to mimic a flashy projector and simulate the look of film. But one more time - that is the wrong goal to emulate the look of a modern digital movie in a digital theater.
The goal is not to mimic current digital theatrical projectors. The goal is to get the best image quality. Why stopping at where current digital theatrical projectors are? They will improve in the future. Doing dark frame insertion is not a retarded way of simulating outdated technology. Instead it's the best currently available way to get rid of the motion blur caused by the sample-and-hold effect.

It takes a period of time. I do think "paradigm shift" is an accurate way to describe it. Once you've made the adjustment, the flaws of 60Hz displays become glaringly obvious
Good displays don't show movies in 60Hz. Instead they use a multiply of 24Hz. I don't know why you're so hung up on 60Hz. You seem to believe that there's only 60Hz or 120Hz. That's just not true. As I repeatedly said, e.g. Pioneer Kuros refresh at 72Hz for movie content.

At 60hz DLP has a hold time of 8.3ms.

LCoS used to have a hold time of 16.7ms, but thanks to 120hz and Black Frame Insertion (BFI) they cut that down to 8.3ms.

But of course the lower amount of time either DLP or LCoS is holding a frame, the lower amount of light that is hitting the screen.

This is area where LED lighting can be a big win for DLP. Every year they get brighter and at some point they'll get bright enough allowing them to reduce the hold time further. The DLP chip is very fast, but light sources aren't bright enough to really take advantage of it. Well except laser. Then the difference between LED and Laser light comes down to heat dissipation.
Thanks, good post!

DLP, LCoS, LCD, AM-OLED, and Plasma are all "sample and hold". How long they "hold" the image for each 16.7ms frame depends on the technology.


CRT is impulse.




For "sample and hold" technologies, as the light sources get brighter they can reduce the hold times if the materials allow it. In the case of DLP, the chip is very fast with the mirrors measured in micro seconds. LCD/LCOS on the otherhand is measured in milliseconds.

Plasma should get more light effcient with the Lumen10 technology.

DLP, LCoS, LCD, AM-OLED, and Plasma are all "sample and hold". How long they "hold" the image for each 16.7ms frame depends on the technology.


CRT is impulse.




For "sample and hold" technologies, as the light sources get brighter they can reduce the hold times if the materials allow it. In the case of DLP, the chip is very fast with the mirrors measured in micro seconds. LCD/LCOS on the otherhand is measured in milliseconds.

Plasma should get more light effcient with the Lumen10 technology.The term "sample and hold" generally refers to a 100% duty cycle achieved by holding the pixel value with a capacitor (AMLCD and AMOLED). If you want to generalize it to mean any length of hold time then CRT is also sample and hold. Like I've said Plasma has ~35% effective duty cycle and CRT has ~10% effective duty cycle. The "effective" part refers to the percieved hold time.

The 120Hz is great - and I view movies at 24Hz with frame interpoolation on High, because it smooths motion and eliminates artifacts.

Frame interpolation on.........on high.........for a movie? GROSS!

The term "sample and hold" generally refers to a 100% duty cycle achieved by holding the pixel value with a capacitor (AMLCD and AMOLED). If you want to generalize it to mean any length of hold time then CRT is also sample and hold. Like I've said Plasma has ~35% effective duty cycle and CRT has ~10% effective duty cycle. The "effective" part refers to the percieved hold time.


Is that the reason why they say you can't compare MPRT numbers between LCD and other technologies?

Plasma has ~35% effective duty cycle and CRT has ~10% effective duty cycle. The "effective" part refers to the percieved hold time.
How about DLP? And I guess dark frame insertion reduces the duty cycle from 100% to 50%, if there's one dark frame shown for each real frame, right?

Thanks!

The term "sample and hold" generally refers to a 100% duty cycle achieved by holding the pixel value with a capacitor (AMLCD and AMOLED). If you want to generalize it to mean any length of hold time then CRT is also sample and hold. Like I've said Plasma has ~35% effective duty cycle and CRT has ~10% effective duty cycle. The "effective" part refers to the percieved hold time.

Hi,

Is there still any research into PMLCD ( passive matrix LCD?). What are the cons with PMLCD? I would like to see LCD with CRT-like motion. Is there anywhere a 3" or 5" PMLCD, that I can buy? Could such a display be fashioned out of off the shelf parts by an electronics hobbyist?