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Author Topic: Canon 5D MkII: almost there  (Read 46951 times)
Ray
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« Reply #40 on: September 22, 2008, 09:47:11 AM »
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24p is not stuttery when played back on a display that actually plays at 24p. It's only stuttery when played back on a display that is refreshing at a rate not evenly divisible by 24 and some frames are displayed for a longer period of time than others. If each frame is not displayed for the same length of time, the video will be stuttery regardless of whether it is 24p or 30p.
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Jonathan,
Despite a lot of Google research, I haven't yet come across any displays that actually play at 24fps. Are you sure you know what you are talking about?

There's an interesting article that explains the issues at [a href=\"http://hometheatermag.com/gearworks/707gear/]http://hometheatermag.com/gearworks/707gear/[/url]

and another article which lists all (or most) of the LCD displays that support 24p, at http://forums.highdefdigest.com/home-theat...frame-rate.html

Almost all of them are 120Hz models and apply a system called 5:5 pull down, but a very few have a 48Hz refresh rate, which seems oddly specialised.
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Ray
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« Reply #41 on: September 22, 2008, 10:08:28 AM »
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But the point is that an LCD does not redraw the whole frame by blacking out and showing a whole new frame every 1/24th sec.  It just changes pixels that change every 1/24th sec.  And the pixels stay lit almost all the time, ie. they are not black 1/2 the time.  So there is no flicker at 24fps.  There is motion judder though.  These new LCD tv's with 120hz refresh rate are interpolating frames and inserting them to eliminate motion judder.  Most filmmakers would rather their viewers turn off this feature and watch at 24fps without adding pulldown and additional frames.  Actually they don't care as long as the dvd is paid for

I have 24 fps video on my web site.  It does not flicker on my LCD display.  It shouldn't, I don't think there is a "refresh rate" for LCD displays.  On my CRT display it plays at 24fps even though my CRT is set to 80hz and refreshes 80 times per second.  It doesn't flicker there either, and it saves bandwidth, allowing a higher quality picture using the same data rate. than 30fps.
[a href=\"index.php?act=findpost&pid=223258\"][{POST_SNAPBACK}][/a]

As far as I understand, all LCDs have a refresh rate. It's usually 60Hz in the case of PC desktop displays, and 100Hz or 120Hz in the case of high-end HD LCD displays.

After some research on the net, I can find no reference to any LCD display with a 24Hz refresh rate. The closest is 48Hz. I can only presume that a refresh rate of 24Hz would be unacceptable with 24p material, whether due to motion blur or judder.

If the 24p source is not an even multiple of the refresh rate, then some fancy processing and conversion has to be applied to prevent obvious artifacts, blur and judder etc.

As I mentioned before, my Sony CRT desktop monitor run by a Win XP64 bit O/S cannot display either 24p or 30p correctly, but my Windows Vista laptop can with no problem.
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Jonathan Wienke
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« Reply #42 on: September 22, 2008, 07:48:05 PM »
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Fading into the next frame...?? Sounds like that would be just fine for a slow moving rustic scene and a gentle breeze. However, you can't have any fading from one frame to the next during fast action. Even though those liquid crystals remain illuminated to some degree all the time, that illumination has to be low in a high quality LCD display suitable for movies, otherwise the contrast ratio would be too poor.

WTF are you smoking??? Let me break the process down into simple steps, using only small words.

At 24 FPS, each frame's display time is 41.667 milliseconds.

Let's pretend the display has a response time of 5 milliseconds.

For 36.667 milliseconds or so, the frame is displayed continuously on the LCD screen, regardless of the internal overscan rate of the LCD panel. At no time during this time period do the screen pixels fade to black.

For the next 5 milliseconds, the screen fades to the next frame. It does not at any time fade to black. The effect from the viewer's perspective is like the new frame being overlaid over the old frame with gradually increasing opacity until the new frame has completely replaced the old frame at the end of the 5-millisecond response time period.

The new frame is displayed for 36.667 milliseconds...

And the cycle continues.

Depending on the particular display, you may be able to observe some refresh artifacts if you photograph the screen at very high shutter speeds. On my 52" Sanyo HDTV, random square portions of the screen will be somewhat dimmer and have a yellowish tint when I use shutter speeds faster than 1/500 or so. But below 1/500, these refresh artifacts disappear and the image appears seamless and even across the entire screen. Most importantly, at no point in the refresh cycle does any portion of the screen fade to black. So while there is a certain degree of high-frequency fluctuation in each pixel's output level due to the refresh process, the process of displaying each frame and transitioning from one frame to the next is fundamentally as described above.
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Ray
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« Reply #43 on: September 22, 2008, 08:14:50 PM »
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WTF are you smoking??? Let me break the process down into simple steps, using only small words.

[a href=\"index.php?act=findpost&pid=223446\"][{POST_SNAPBACK}][/a]

Let me try to break through some of the mumbo jumbo and apparent confusion in your mind.

24 frames per second doesn't work as 24fps. It's not acceptable quality. If footage is recorded at 24 frames per second, it's never played back at 24 frames per second, as far as I can tell. Correct me if I'm wrong. It's played back at a minimum of 48 frames per second, and on the most modern LCD displays at 120 frames per second.

A similar situation applies to 30p, except that 30 fps is at least to some degree better than 24p, and doubling that 30p frame rate to 60fps is smoother (or has less blur motion) than 48 fps.

My initial post in this thread was an attempt to explain to someone who was asking "Why, why, why 30p?" as though 24p was in some way inherently better.

I can find no reason why 24p should be inherently better than 30p, or in the final analysis even as good.

Also, I can find nothing in your posts on this topic that even alludes to any advantage of 24p.

I'll just add a further note of clarfication because we are not entirely at cross purposes, although it might seem that way. I understand your point that flicker is largely a property of CRTs and Plasma displays, and that, whilst a refresh rate of 24fps on a CRT would be horrendous, on an LCD display it would not necessarily be too bad because the transition to a different frame every 24th of a second does not involve a momentary reversion to black.

The only point I have ever been trying to get across in this discussion, a point which seems to have escaped you, is that 24 fps is not enough for totally smooth and realistic motion. 30fps may also not be enough, but it's better than 24 fps and also lends itself more easily to display on a 60Hz system.
« Last Edit: September 22, 2008, 08:40:35 PM by Ray » Logged
witz
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« Reply #44 on: September 22, 2008, 08:45:29 PM »
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24p is just a paradigm of modern cinema film making.... it's a convergence of acceptable cadence and length of film footage shot per roll.... a basic industry efficiency. That's all. Today... we can shoot DIGITALLY at other FPS and get away with them being wrapped in various wrappers using various codecs.

I own and use a sony xdcam ex1 that will shoot 1080 24p & 30p... also 720 24p, 30p, & 60p.... I only shoot 1080 24p (unless I'm shooting slowmo and use 720 60p... slowed down to 30p in post) because it allows for the most efficient use of the 35mb per second bandwidth. the resulting video is less compressed per frame than 30p, and higher rez than 720p.

When I play the 1080 24p footage on my macpro + 30" acd.... it does not judder or stutter. it looks fantastic. When I convert the footage to appletv spec and play it on my appletv/1080p projector.... it still looks fantastic. If I burn a 1080 24p BR disk and play the footage through a BR player... guess what? it looks fantastic.... just like a theatrical release in 24p!

note; fake 24p from interlaced cameras can appear to be stuttery and juddery.

note B; personally... I'm very bummed that the 5d2 is 1080i. ( per Michael's review ) I'm hoping he has made an error.
« Last Edit: September 22, 2008, 08:47:10 PM by witz » Logged
Ray
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« Reply #45 on: September 22, 2008, 09:20:44 PM »
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note B; personally... I'm very bummed that the 5d2 is 1080i. ( per Michael's review ) I'm hoping he has made an error.
[a href=\"index.php?act=findpost&pid=223460\"][{POST_SNAPBACK}][/a]

I noticed that too. Since Michael was handed the 5D2 just a couple of days before departing for Botswana, I guess we can forgive him for that slight error   .

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I only shoot 1080 24p (unless I'm shooting slowmo and use 720 60p... slowed down to 30p in post) because it allows for the most efficient use of the 35mb per second bandwidth. the resulting video is less compressed per frame than 30p, and higher rez than 720p.

Well, there you are! You've hit the nail on the head   . The advantages of 24P. It saves bandwidth.

With proper processing, the inhernet advantages of 30p with its greater data throughput is probably undiscernible by all but the most dedicated viophile.
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« Reply #46 on: September 22, 2008, 10:21:25 PM »
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Ray, I have a BA from one of the best film schools in the world. This was part of our "fysiology and film" lessons. I do not use the internet to find support for what was taught to me. This information was presented to us by a scientist who was specialized in this kind of research. I have no reason to believe he was wrong. But feel free to believe whatever you like.
[a href=\"index.php?act=findpost&pid=223471\"][{POST_SNAPBACK}][/a]

The only belief system I operate on is that every specialist can be wrong some of the time, or can later proved to be wrong as scientific knowledge progresses.

You could be making a mistake if you think that everything you were taught at school is correct.

I merely asked you for your sources. Give me a link to the views of the scientist who taught you, so I can make up my own mind as to his reliability, if his opinions differ from other authorities.

Edit: this what Wikipedia also has to say on the subject of Alpha waves.

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Alpha is the frequency range from 8 Hz to 12 Hz. Hans Berger named the first rhythmic EEG activity he saw, the "alpha wave." This is activity in the 8-12 Hz range seen in the posterior regions of the head on both sides, being higher in amplitude on the dominant side. It is brought out by closing the eyes and by relaxation. It was noted to attenuate with eye opening or mental exertion. This activity is now referred to as "posterior basic rhythm," the "posterior dominant rhythm" or the "posterior alpha rhythm."

The posterior basic rhythm is actually slower than 8 Hz in young children (therefore technically in the theta range). In addition to the posterior basic rhythm, there are two other normal alpha rhythms that are typically discussed: the mu rhythm and a temporal "third rhythm". Alpha can be abnormal; for example, an EEG that has diffuse alpha occurring in coma and is not responsive to external stimuli is referred to as "alpha coma".
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jjj
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« Reply #47 on: September 23, 2008, 05:06:46 PM »
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The only belief system I operate on is that every specialist can be wrong some of the time, or can later proved to be wrong as scientific knowledge progresses.
I don't recall you ever believing anything anyone else says, no matter what.  

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You could be making a mistake if you think that everything you were taught at school is correct.
But I do agree with this.
« Last Edit: September 23, 2008, 05:07:41 PM by jjj » Logged

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Jonathan Wienke
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« Reply #48 on: September 23, 2008, 08:14:53 PM »
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24 frames per second doesn't work as 24fps. It's not acceptable quality. If footage is recorded at 24 frames per second, it's never played back at 24 frames per second, as far as I can tell. Correct me if I'm wrong. It's played back at a minimum of 48 frames per second, and on the most modern LCD displays at 120 frames per second.

You're wrong. An LCD HDTV displays each 24p frame for approximately 1/24th of a second, minus a transitional period during which a frame is replaced by the next frame in the sequence. All increasing the refresh rate does is reduce the amount that each pixel's output level fluctuates during the frame display period, and reduce the response time. It does not increase the frame rate above 24 FPS.

The only time displaying a frame multiple times is necessary to avoid perceptible flickering is when the display device (CRT or projector) must fade to black for a significant portion of the display cycle. This is not true of LCD displays, which display each 24p frame continuously for 1/24th of a second time regardless of the underlying refresh rate. If you don't believe this, conduct the experiment I proposed in my previous post. Until you have done so, kindly refrain from posting any more ignorance here.
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Ray
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« Reply #49 on: September 23, 2008, 09:59:44 PM »
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You're wrong. An LCD HDTV displays each 24p frame for approximately 1/24th of a second, minus a transitional period during which a frame is replaced by the next frame in the sequence. All increasing the refresh rate does is reduce the amount that each pixel's output level fluctuates during the frame display period, and reduce the response time. It does not increase the frame rate above 24 FPS.

The only time displaying a frame multiple times is necessary to avoid perceptible flickering is when the display device (CRT or projector) must fade to black for a significant portion of the display cycle. This is not true of LCD displays, which display each 24p frame continuously for 1/24th of a second time regardless of the underlying refresh rate. If you don't believe this, conduct the experiment I proposed in my previous post. Until you have done so, kindly refrain from posting any more ignorance here.
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Jonathan,
Please inform the manufacturers of LCD displays of this 'correct' information. I'm sure they would benefit greatly, as well as the multitude of videophiles who discuss such matters endlessly.

My initial statements on the issue of 24p (on page #1) were not specific to any display type. You've pointed out that LCDs do not suffer from flicker as much as other types of displays, and I have agreed with you on this point.

However, LCDs have their own problems as a consequence of this difference. There can be problems of judder and motion blur due to the 'sample and hold' effect.

Some manufacturers have tried to solve this problem by designing an LCD with a flashing back-light. It flashes off during the changes between frames.

Some of the latest models of LCD TVs employ large numbers of LED back lights instead of fluorescent lighting, which can almost instantaneously brighten and dim  the parts of the displayed scene which change from bright to dark, in order to increase contrast ratio. (A slight variation of your constant back-lighting theme you mentioned in an earlier post, wouldn't you say?)

There's a lot of sophisticated technological development in modern LCD TVs to help make images as smooth, as judder-free and as blur-free as possible. Your simplistic right and wrong attitude is making you sound like a religious fundamentalist.

Here's a primer on the current state of affairs. If this overview is not factual, perhaps you would like to point out the errors so we can all benefit.

[a href=\"http://hometheatermag.com/gearworks/707gear/]http://hometheatermag.com/gearworks/707gear/[/url]
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smthopr
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« Reply #50 on: September 23, 2008, 10:35:39 PM »
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You're wrong. An LCD HDTV displays each 24p frame for approximately 1/24th of a second, minus a transitional period during which a frame is replaced by the next frame in the sequence. All increasing the refresh rate does is reduce the amount that each pixel's output level fluctuates during the frame display period, and reduce the response time. It does not increase the frame rate above 24 FPS.

The only time displaying a frame multiple times is necessary to avoid perceptible flickering is when the display device (CRT or projector) must fade to black for a significant portion of the display cycle. This is not true of LCD displays, which display each 24p frame continuously for 1/24th of a second time regardless of the underlying refresh rate. If you don't believe this, conduct the experiment I proposed in my previous post. Until you have done so, kindly refrain from posting any more ignorance here.
[a href=\"index.php?act=findpost&pid=223783\"][{POST_SNAPBACK}][/a]
Jonathan,

You are absolutely correct!  And, I not only went to film school, I actually shoot movies  

I have also shot movies of all types of display screens.  And I can tell you that CRT's flicker, and of course, projected movies flicker.  Shooting with a movie camera requires syncing of the camera with the device. With CRT, we play 24fps video on a special CRT display (often put inside a "tv" cabinet) and the playback sync drives the camera speed.  Amazingly, plasma displays and LCD displays require no sync or 24fps playback when shooting with a movie camera.  Interestingly, I've seen some exposure variation when shooting LCD and Plasma displays with a digital movie camera and I've had to adjust the frame shutter speed (not the fps) to eliminate this effect.  I suspect that with the LCD, this is caused by some 60hz flicker involving fluorescent back lighting.  I don't know what happens with the plasma.  It's interesting that we don't see this when shooting 24fps on a analog movie camera.

I've also noticed some exposure variation using HMI lights and some fluorescent lights with a digital movie camera that don't show up on a spinning shutter movie camera.  I've checked the power supply frequency and found it accurate, yet had to change the frame exposure to 1/60th sec to get rid of the variation.  And I was shooting with a CCD imager that shouldn't have the "rolling shutter" of a CMOS imager...

And one more example:  When shooting with a Sony Cine-Alta digital cinema camera out putting 24fps over HDSDI, there is a pronounced flicker on a CRT HD display.  The flicker disappears when displaying on my LCD HD monitor that displays almost every format known to exist, including 24fps.

And for Ray, 30P does look better than 24P.  However, 24P is more easily used for conversion to 25p, 50i, 30p, 60i and 24fps film display.  And yes, it saves bandwidth for the web. So, 24p is a very important feature today when display standards used are still linked to the movie and tv standards of the last century.  When everyone has a digital, variable frame rate display and transmission system, the filmmaker will be able to choose any frame-rate.  Until then (I don't think in my lifetime!), 24p is a necessary feature for professional use.

I don't know why I'm getting involved in this, but it's nice to be right more often than a broken clock once in a while
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Bruce Alan Greene
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Ray
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« Reply #51 on: September 23, 2008, 11:37:07 PM »
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I have also shot movies of all types of display screens.  And I can tell you that CRT's flicker, and of course, projected movies flicker.  Shooting with a movie camera requires syncing of the camera with the device. With CRT, we play 24fps video on a special CRT display (often put inside a "tv" cabinet) and the playback sync drives the camera speed.  Amazingly, plasma displays and LCD displays require no sync or 24fps playback when shooting with a movie camera.  Interestingly, I've seen some exposure variation when shooting LCD and Plasma displays with a digital movie camera and I've had to adjust the frame shutter speed (not the fps) to eliminate this effect.  I suspect that with the LCD, this is caused by some 60hz flicker involving fluorescent back lighting.  I don't know what happens with the plasma.  It's interesting that we don't see this when shooting 24fps on a analog movie camera.
[a href=\"index.php?act=findpost&pid=223809\"][{POST_SNAPBACK}][/a]

I've never argued that LCD displays exhibit flicker like a CRT. My original comments were made in relation to displays in general. As as I understand, those who want the best quality image playback don't buy LCD displays. Image quality is still not quite up to scratch on LCDs, compared with Plasma sets, and even some CRTs might still have a slightly better contrast ratio than the best Plasma displays.

The sets that have a reputation for the highest contrast ratio and the best blacks are the latest 9th generation Pioneer Kuro Plasmas.

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And for Ray, 30P does look better than 24P. However, 24P is more easily used for conversion to 25p, 50i, 30p, 60i and 24fps film display.

Please explain how 24p is more easily used for conversion to 30p and 60i.

Also, bear in mind that this discussion between Jonathan and myself began with my attempt to explain why the 30fps at 1080p (aka 30p) that the 5D2 seems to support is not such a bad thing for those who are concerned with maximum image quality.

As someone who claims to have gone to film school, you should be aware that 24p on modern electronic displays is sometimes preferred because it emulates the slight stutter (perhaps almost impreceptible) of conventional film movies in the cinema. If Jonathan is right, then an LCD would defeat this effect. Instead of the almost imperceptible stutter, one is instead left with blurring during fast movement, loss of resolution and 'sample & hold' artifacts which seem to involve a lot of complicated processes to remove.
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smthopr
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« Reply #52 on: September 24, 2008, 01:12:51 AM »
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I've never argued that LCD displays exhibit flicker like a CRT. My original comments were made in relation to displays in general. As as I understand, those who want the best quality image playback don't buy LCD displays. Image quality is still not quite up to scratch on LCDs, compared with Plasma sets, and even some CRTs might still have a slightly better contrast ratio than the best Plasma displays.

I'm not an expert on consumer displays...but, certainly the CRT has the darkest black.  Certainly much more so than a projected movie on a white screen in a dark room.  I haven't yet seen an LCD display that I would buy for my home, but CRT's don't come in large sizes and they don't make rear projection CRTs anymore.  Though I still watch my dvd movies at home on a 40" widescreen CRT rear projector.  It's not perfect, but it's quite good for standard definition DVD's.
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The sets that have a reputation for the highest contrast ratio and the best blacks are the latest 9th generation Pioneer Kuro Plasmas.
Please explain how 24p is more easily used for conversion to 30p and 60i.
24p is converted to 30p/60i by adding duplicate frames in what is called "3:2 pulldown".  It's what you see on tv for all US tv shows shot on film.  The motion is a little uneven, but we've grown accustomed to it.  Going from 30P to 24P involves deleting frames and the motion is very jerky looking. 24P also converts to 25p/50i by speeding up the playback to 25fps which is hard to notice.
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Also, bear in mind that this discussion between Jonathan and myself began with my attempt to explain why the 30fps at 1080p (aka 30p) that the 5D2 seems to support is not such a bad thing for those who are concerned with maximum image quality.
It's good for image quality, but not the most flexible for professional exhibition standards that include 25p and 24p.  It's perfect for 60i.
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As someone who claims to have gone to film school,
I love your use of "claims"!
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you should be aware that 24p on modern electronic displays is sometimes preferred because it emulates the slight stutter (perhaps almost impreceptible) of conventional film movies in the cinema. If Jonathan is right, then an LCD would defeat this effect. Instead of the almost imperceptible stutter, one is instead left with blurring during fast movement, loss of resolution and 'sample & hold' artifacts which seem to involve a lot of complicated processes to remove.
[a href=\"index.php?act=findpost&pid=223822\"][{POST_SNAPBACK}][/a]

No, LCD with a fast enough reaction time don't really blur, but do show the motion judder of 24fps material.  When 3:2 pulldown is added and displayed at 60i it's harder to see, but interlace artifacts are introduced on motion.  But when viewing material shot in 24fps, you can't really add data or frames that aren't there without changing the feeling of the movie.  Personally I don't think 24fps is more esthetically pleasing than 30fps.  People get very used to viewing moving images in a certain way and become very aware of any changes in the frame rate or origination material.  Hence a lot of talk about getting digital capture to look like film!

Ray, I hope I have answered your questions to your satisfaction.  Yes, I really went to a film school. Really.  But that's not where I learned any of this stuff...
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« Reply #53 on: September 24, 2008, 01:57:48 AM »
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24p is converted to 30p/60i by adding duplicate frames in what is called "3:2 pulldown".

Whereas 30p can be converted into either 30p (no conversion required really) or 60i much more easily, which was the obvious point I made at the beginning of the discussion.

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No, LCD with a fast enough reaction time don't really blur, but do show the motion judder of 24fps material.

This is the matter that needs clarification. I certainly don't pretend to be an electronics expert, but there seems to be a consensus of opinion amongst reviewers of LCD displays, writers of articles in computer magazines and articles on Wikipedia, that an unmodified 24 fps has problems with blurring and other artifacts during fast movement.

The latest LCD displays operating at 120Hz get around these defects with a process called 5:5 pull down which results in a completely smooth and sharp result; no judder, no blurring; no halos; no trailing, thus completely destroying the almost imperceptibly stuttery effect of a true 24fps that seems to be the main purpose of using 24p in the first instance.

This is what Wikipedia has to say on the disadvantages of 24p.

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Disadvantages of 24p

24p video has more trouble with high motion than other, higher frame rates, sometimes showing a "strobe" or "choppy" motion, just like 24 frame/s film will if shot as if it's video, without careful panning, zooming, and slower camera motion.

It is therefore not well-suited for programming requiring spontaneous action or "reality" camerawork. 24p can also hurt the credibility of newscasts by making news footage look too much like staged movie clips – though many newscasts do incorporate 24p footage.

It should also be noted that while the strobe of 24p is in many ways considered a disadvantage, it's also part of the "film look." 24 frame/s film strobes in exactly the same way.

Most consumer-level video editors (particularly non-HD ones) are designed for 30 frames per second, and the addition of 24p is sometimes awkwardly implemented. Incorrect user settings can result in a 24p frame at the edge of an edit existing on only one NTSC field, thus cutting its resolution in half. If a non-linear editor is incapable of removing pulldown, the standard 3:2 pulldown pattern should be used when shooting.

This what PC Magazine has to say on the subject.

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One of the primary benefits that plasma displays offer over LCD technology is the ability to display fast moving imagery with little loss of detail—you could say that plasmas offer superior pixel performance.

Modern LCDs employ a bevy of techniques to reduce apparent blurring and other motion-related artifacts and 120Hz imaging is the latest improvement. Most liquid crystal televisions produce imagery on a 60Hz cycle—the entire screen, or frame, is updated every 1/60 of a second. The doubling of the display's refresh speed doubles the amount of visual information presented to our eyes every second, thereby offering improved image detail with fast moving imagery.

However, the current generation of 120Hz liquid crystal HDTVs is achieving this performance using frame interpolation—adjacent frames within a 60Hz source are analyzed and an interpolated frame is then inserted. When everything works well, this technique does indeed produce more detailed, clearer imagery.

Where frame interpolation doesn't help is with 24p content such as most movies that were originally shot on film or recorded with the latest 1080p24 digital cinema cameras. Since 24p video and 60Hz displays do not share equal timing, a process called telecine is used to make ends meet. The telecine process inserts repeated frames (or fields) into the video in a specific, repeating pattern. The odd cadence resulting from this conversion can be observed on most TVs during slow panning shots where a slight visual jerkiness is observed—also called judder.

 A true 120Hz display could take 24p material and simply show every frame five times (5 x 24 = 120) resulting in smooth fluid motion even in those challenging panning shots.
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« Reply #54 on: September 24, 2008, 12:33:02 PM »
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Whereas 30p can be converted into either 30p (no conversion required really) or 60i much more easily, which was the obvious point I made at the beginning of the discussion.
This is the matter that needs clarification. I certainly don't pretend to be an electronics expert, but there seems to be a consensus of opinion amongst reviewers of LCD displays, writers of articles in computer magazines and articles on Wikipedia, that an unmodified 24 fps has problems with blurring and other artifacts during fast movement.

The latest LCD displays operating at 120Hz get around these defects with a process called 5:5 pull down which results in a completely smooth and sharp result; no judder, no blurring; no halos; no trailing, thus completely destroying the almost imperceptibly stuttery effect of a true 24fps that seems to be the main purpose of using 24p in the first instance.

This is what Wikipedia has to say on the disadvantages of 24p.
This what PC Magazine has to say on the subject.
[a href=\"index.php?act=findpost&pid=223850\"][{POST_SNAPBACK}][/a]

Ray, methinks you think that because something is in a PC magazine or the wiki it must be true.

If 5:5 pulldown results in a completely smooth movement, it must use interpolated frames.  If you like the effect, fine buy the tv, but it's just interpolated data. If no interpolation is used it will look identical to 24fps displayed on an LCD.

Duh, of course 24fps has issues with blurring.  Each frame is exposed for 1/48th sec so everything that moves blurs.  When this movement blur is gone the motion looks very stroboscopic.  But shooting at higher frame rates such as 60fps shows strobing also, but at a more natural rate.  Maybe shooting 120fps (and playback) solves the problem, but the data storage and speed required makes it impractical for the time being.  30fps still has enough motion blur to look natural, 60fps does not in my opinion but it is one of the HD broadcast standards now in use and works great for live sports.  I think ABC and FOX broadcast in 720p 60fps.  Of course, they add pull down to all 24fps programing to broadcast at 720p60.

There is so much pseudo expert opinion on the web, you have use a critical eye when reading so called experts.  Except for myself
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« Reply #55 on: September 24, 2008, 01:12:14 PM »
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Duh, of course 24fps has issues with blurring.  Each frame is exposed for 1/48th sec so everything that moves blurs.  When this movement blur is gone the motion looks very stroboscopic.
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For an example of this, the beach landing in Saving Private Ryan was shot using a higher shutter speed than normal to give the jerky look.
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« Reply #56 on: September 24, 2008, 08:18:37 PM »
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Ray, methinks you think that because something is in a PC magazine or the wiki it must be true.

I don't know how I have given that impression  . Perhaps I could say, methinks you think that because someone claims to be an expert, every opinion they express on the subject of their claimed expertise must be correct.

It's true that there is a lot of pseudo opinion on the net, and coincidentally we are also both on the net as we express our opinions on this matter. In the light of this, I tend to go with the consensus of opinion amongst claimed experts, unless I have direct personal experience which might suggest the consensus is false, or unless I hear a dissenting voice which makes a compelling and reasoned case.
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« Reply #57 on: September 24, 2008, 08:53:22 PM »
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I don't know how I have given that impression  . Perhaps I could say, methinks you think that because someone claims to be an expert, every opinion they express on the subject of their claimed expertise must be correct.

It's true that there is a lot of pseudo opinion on the net, and coincidentally we are also both on the net as we express our opinions on this matter. In the light of this, I tend to go with the consensus of opinion amongst claimed experts, unless I have direct personal experience which might suggest the consensus is false, or unless I hear a dissenting voice which makes a compelling and reasoned case.
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I believe I was compelling and reasoned in my post.  I rest my case.

Nice chatting with you Ray!
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Bruce Alan Greene
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