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24fps 120hz etc. Help

4145 Views 46 Replies 13 Participants Last post by  frito
I'll keep this brief but I need some information. I am looking at moving up to 120hz from a 60hz lcd display. I would like to do this in order to take advantage of 24fps for Blu-ray. My in-laws recently purchased a display with 120hz and the Blu-ray looked almost like live TV. A friend of mine recently purchased a 120hz display as well. And his doesn't look much better than mine. So my question is this: in order to achieve the best possible Blu-ray picture, I realize I have to have a TV capable of decoding a 24fps signal, but is there technology that I need to consider other than the hz, such as Smooth-Motion, CineMotion, etc.? Hope that made sense and thanks in advance for any help.
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I think you're mixing up a couple of things here. 120Hz sets display 24fps material by repeating each frame five times per second.


But this doesn't result in the "live" look that you referred to - that's the result of frame interpolation - i.e. "Cinemotion" or "Smooth Motion" or whatever a particular manufacturer calls it. In effect, the set is creating new frames by "guessing" what should be in between the existing frames. This creates motion that is "smoother", but also less natural looking.


Using frame interpolation negates the point of sending the set a 1080p/24 signal, because the set is creating frames that aren't present in the original material.


In other words, if you want to see the film as it's actually stored on the disc, you have to make sure that frame interpolation is switched off. But if you like that "live", smoother motion look, switch motion interpolation on - in which case you're no longer really seeing 24fps.
If you are sending 1080p/24 content to a 120Hz unit then you also have to make sure that your settings for "motion flow" and/or "real cinema" (or what ever they are called for your make/model TV) are set up correctly to insure that 5:5 pulldown or an equivalent solution is being used to display each 24Hz frame the same number of times.

Some older 120HZ models do not even have this option.

Also the different manufacturer's use similiar sounding terms and setting options so you have to read the user manual for the specific make/model of 120Hz you have or are considering buying closely for details
Thank you so much for the info!


It makes so much more sense now that someone has explained it on a more basic level. So by way of follow up, if I choose to not use the interpolation effect, can I expect a noticeable difference going 60hz to 120hz as far as bluray is concerned (24fps)?
For 24Hz blu-ray you only want to use a "cinema mode" or "Judder reduction feature" that is documented in the user's manual to display each frame of 24fps content the same number of times using 5:5 pulldown or equivalent feature.
Hold on, folks, you are all ahead of yourselves. nickle15, when you feed a 60Hz video signal to a 120Hz set, it will look much the same as it does on a 60Hz set, and technically, you will be using 2:2 pulldown from 60Hz to 120Hz.


For TRUE 24fps operation, you need a Blu-Ray player capable of outputting the native 24fps Blu-Ray disk content. That is definately NOT a feature that is available on all Blu-Ray players, nor is it enabled by default on any Blu-Ray player, because most displays are 60Hz. If you want 24fps playback, you must have a newer player that supports it, and you must then go into the setup menu and turn the feature on.


I use a PS3 for Blu-Ray playback at 24fps, and a Toshiba HD-DVD player for playback at 24fps, and a HTPC that can be set for 24fps playback from vanilla DVDs, after "reverse telecine processing" that recovers the original 24fps film frames from the disk.


Now, once you have the 24fps video signal working, THEN you can play around with the various settings for frame interpolation, and decide if you like it or not.
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Out of curiosity is what the OP stating "almost like live tv" what one considers the "soap opera effect"?
Rocky1 - Yes, the soap opera effect sums it up. That's what I was referring to.



Gary - I use a PS3 for Blu-ray output, so I'm covered on the 24fps capability. I would just like to move up to a display that doesn't do the 3:2 (?) pulldown.


I actually kind of liked the interpolation effect when I saw it on another TV, but my goal is having the ability to watch true 24fps. So to reiterate an earlier question, will I notice a difference between what I see now (60hz TV) and a 120hz display showing a Blu-ray at 24fps? And thank you all for your input. I appreciate it very much.
Rocky1, the SOE is the opposite of what you are used to seeing on a video display.


You probably grew up as did most of us, watching NTSC standard-definition programming, that for the most part was shot on FILM at 24fps. Then the film was "telecined" to broadcast this 24fps over a 60Hz NTSC video signal, which gave a distinct and uneven on-screen motion to moving objects, and frequent "artifacts" which resulted from interlacing.


The other and less utilized practice for recording video productions, was to shoot the production straight onto video tape at either a 30fps or 60fps frame rate. This provided an extra clarity and a natural movement that film material lacked. For many years the main uses of video recordings were 1) Soap Operas and 2) camcorders used for news broadcasts. These 30fps or 60Hz video recordings (interlaced to 60Hz), displayed an extra clarity not seen on film recordings.


In truth the 24fps film standard was established by Thomas Edison in 1896, with the motive of standardizing the commercial theaters for more profit, allowing any studiio's film to be shown in any theater. For over a century, 24fps was THE standard.


Nowadays with ATSC broadcasts, many prime time series are shot directly onto videotape, such as the "Law and Order" series, with the irritating hand-held cameras. But the ATSC standard does not allow enough bandwidth for a 720p60 broadcast when the camera pans - it forces every pixel to change in every frame, and the digital compression is overwhelmed and the image displays a flaw called "macro-blocking of pixels", especially if some of the bandwidth was stolen with multiple SD "sub-channels".


However when that same video signal is played back from a DVD or Blu-Ray disk, there is not a bandwidth limitation, and incredible fidelity can be had. For example, stick a Blu-Ray recording of the BBC series Planet Earth into your player, and output the 60Hz video signal to a 120Hz or 240Hz LCD display. The result is incredible fidelity, as good ast it gets - you almost get vertigo and think you are looking through a pane of glass into another world.


That is SOE. Some of us LOVE IT, because it frees us from the 100-year-old limitations of film.


Nickle15, the 24Hz video will look nearly exactly like film in a theater on a 120Hz display, a series of frames where the image changes 24 times/sec. With frame interpolation OFF, the output frame buffer of the display will repeat each input frame 5 times, "5:5 pulldown", and if you are viewing in complete darkness, it will look remarkably like film. However if you turn on room lighting, you will start to notice flicker as the 24fps video and the 60Hz lighting interact at night. You can minimize this effect by using incandescent room lighting, which does not vary in intensity as much as does flourescent lighting.


But IMHO the very best result involves MCFI, Motion Compensating Frame Interpolation, which synthesizes frames between the input video frames. Film lovers call it "SOE" and discuss it as being "unreal". I find this curious - because the high frame rate video approximates real life, where objects have an effectively infinite frame rate.
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I've seen the SOE on a samsung 8500 and on some other displays.I personally dont like it.I saw one of the Xmen bd with this effect and it looked synthetic or cartoonish.Some people i know like it alot.Just goes to show you how everyone differs.

Quote:
Originally Posted by Gary McCoy /forum/post/18155768


Hold on, folks, you are all ahead of yourselves. nickle15, when you feed a 60Hz video signal to a 120Hz set, it will look much the same as it does on a 60Hz set, and technically, you will be using 2:2 pulldown from 60Hz to 120Hz.

The only way you will get 2:2 pulldown from 60Hz content sent to a 120Hz set is if the frame interpolation feature (what ever it is called on the particluar set is turned off and the content does not have Inverse Telecine applied to it.
MFCI has nothing to do with being more "realistic" - it's designed to mitigate a shortcoming in sample-and-hold displays like LCD that causes people to perceive blurry motion. The look imparted by MFCI - especially with 24fps material - is even more artificial than the look imparted by film. Film only captures real motion (obviously with certain artifacts depending on the speed of the motion), whereas MFCI has to make basic assumptions about all motion to create artificial frames, linearizing movement where it is often not supposed to be linear, hence the "cartoonish" or "fast-forward" look. I'd rather watch material captured at 24fps at its native framerate rather than displayed at 240fps with multiple artificial, unrealistic frames in between each frame; most people I've talked to about this in person feel the same way.


Once again, the sole purpose of a display is to accurately reproduce what's sent to it - not to simulate reality. Most material that we watch is meant to simulate some sort of fantasy, not recreate reality; a good display will reproduce realistic and fantasy material equally well while a poor display will not. If all people want is reality, they should be out in the real world using all of their senses and not trying to artificially recreate it on a display with processing trickery.
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There are two basic ways to play 24fps content on a 240Hz display;

1, Using frame interpolation which will create either one or three interpolated frames between each pair of 24fps frames see the following link:

http://reviews.cnet.com/8301-18438_7-10243372-82.html


2. Using 10:10 pulldown which displays each 24fps frame unaltered the same nunmber of times.


There is no implementation that creates 9 interpolated frames between each pair of 24fps frames.
Corrected, thanks.
nick as i read ur post i want to say stop , first how nice or better the picture quality of the tv looks has nothing to do with hz of given tv so going from 60hz 120hz or 240hz is a differnt feel but not improved picture quality, if you want better picture quality get a higher end tv be it a pioneer plasma or a sony xbr8 that will get you improved PQ at a cost of course. now just by going to a newer model you should see beter PQ how much is the question again on which tv you get. now u want to watch blu ray at 24fps but u got a lcd?¿?? if u want a a smooth 24fps as the directors intended then atleast turn off the frame soe trick off so 120/240 hz will be disabled and thus back to same square so move up to plasma.


Quote:
Originally Posted by nickle15 /forum/post/18153261


I'll keep this brief but I need some information. I am looking at moving up to 120hz from a 60hz lcd display. I would like to do this in order to take advantage of 24fps for Blu-ray. My in-laws recently purchased a display with 120hz and the Blu-ray looked almost like live TV. A friend of mine recently purchased a 120hz display as well. And his doesn't look much better than mine. So my question is this: in order to achieve the best possible Blu-ray picture, I realize I have to have a TV capable of decoding a 24fps signal, but is there technology that I need to consider other than the hz, such as Smooth-Motion, CineMotion, etc.? Hope that made sense and thanks in advance for any help.
Maybe someone can explain:


1. If a 24 fps movies is displayed on LCD at 120 or 240 Hz or even on plasma at 72 or 96 Hz how is the motion blur or judder improved that is inherently in the film because of the lousy 24 fps by simply by repeating the frames.


2. To improve the judder or blur to some extent, do you not need some sort of frame interpolation instead of just repeating the same frame multiple times?


Some TVs have separate blur and judder controls and one might be able to dial in the right setting which helps these artifiacts lessen without making it look like video too much.


BTW, why is 24 fps look realistic? I find the blur/judder in 24 fps annoying and I am not sure why some are hung up on it. It is a 100 year old concept we need to move on to higher sample rates, no? (p.s. I do not like the soap opera look myself either, but do not accept the shortcomings of 24p film either).
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Quote:
Originally Posted by dandaroy /forum/post/18170662


Maybe someone can explain:


1. If a 24 fps movies is displayed on LCD at 120 or 240 Hz or even on plasma at 72 or 96 Hz how is the motion blur or judder improved that is inherently in the film because of the lousy 24 fps by simply by repeating the frames.

Adding synthetic frames and refreshing the display at a higher framerate doesn't fix motion blur that's captured on the film, that's inherent to the source and not caused by the display. Judder is something different altogether, and is fixed by displaying 24fps material at some multiple of that rather than using 2:3 pulldown.

Quote:
Originally Posted by dandaroy /forum/post/18170662


BTW, why is 24 fps look realistic? I find the blur/judder in 24 fps annoying and I am not sure why some are hung up on it. It is a 100 year old concept we need to move on to higher sample rates, no? (p.s. I do not like the soap opera look myself either, but do not accept the shortcomings of 24p film either).

Film isn't realistic - as with any other art, as a medium film has certain visual characteristics which result from its physical structure and the capture speed. Maybe some day when digital capture becomes more prevalent and can approach the abilities of film, directors will be able to choose from a wide variety of "looks," one of which could be that of film. However I'm a huge proponent of using higher capture framerates to eliminate the artifacts caused by recording various rates of movement at 24fps. That being said, as long as the majority of movies are shot on film, I really don't think we'll see an increase in capture framerate since - for example - 48fps would double the amount of film (and associated costs) required. For the time being I think that the benefits of film over digital capture mediums still far outweigh the drawbacks, but maybe some day that will change.
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Quote:
Originally Posted by HogPilot /forum/post/18170801


Adding synthetic frames and refreshing the display at a higher framerate doesn't fix motion blur that's captured on the film, that's inherent to the source and not caused by the display. Judder is something different altogether, and is fixed by displaying 24fps material at some multiple of that rather than using 2:3 pulldown.

Understand about the blur, but how is judder improved if the frames are just repeated rather frames inserted (regardless of how it looks). If the frame is merely repeated since it is the same frame, how would that help judder? Maybe I do not understand how judder gets in 24p film (I understand how it does in 3:2 pulldown, but we are not talking about that).


Care to explain? Also if you could answer my other recent thread, I would appreciate it.
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Quote:
Originally Posted by dandaroy /forum/post/18170833


Understand about the blur, but how is judder improved if the frames are just repeated rather frames inserted (regardless of how it looks). If the frame is merely repeated since it is the same frame, how would that help judder? Maybe I do not understand how judder gets in 24p film (I understand how it does in 3:2 pulldown, but we are not talking about that).

Using 120Hz (5:5) or 240Hz (10:10) eliminates the judder associated with 3:2 pulldown and that is all. It's not designed to do anything for judder present in the source film.
I think your getting judder and film edge flicker confused


judder is only seen in films where there is something moving at a constant speed on the screen like when a camera pans or when credits are rolling at the end of a movie and what it does is makes it look like its studdering or moving at a different rate when it should not be


film edge flicker is the blur created by fast moving objects that is also very commonly noticed in the very same panning scenes as well as the credits and is due to the low frame rate of film


think of it like this every dash i put below is a frame


3:2 pulldown judder

--_--_--_--_--


the - is a frame at normal speed

the _ is a lengthened frame to make up for the difference between 24 and 30 fps so smooth motion appears to studder on the screen


2:2,5:5 pulldown looks like this

---------------

every frame is displayed for the same amount of time but you still see edge flicker and you see it much more on LCD's than on Plasma, CRT or film in a movie theater because of LCD's sample and hold type of display combined with LCD's overall poor pixel response time in comparison to the other common tech's out there


if you don't believe me or understand what I'm talking about go see a movie in the theater (not one using a digital projector or IMAX either because they do not look the same as normal film projection) and you will see that film edge flicker is there as well, its part of what makes movies look like movies and motion enhancers work to remove that look from them in order to make motion appear smoother on an LCD


this is one of the reasons why plasma is the preferred display type for movie watching even with judder motion in films looks more natural overall than on most if not all 120/240 hz LCD's
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