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24fps confusion

post #1 of 15
4/28/10 at 6:13pm
Thread Starter 
So I was looking at a tv, http://www.bestbuy.com/site/LG+-+55%...d 55&cp=1&lp=1

One of the reasons I want a tv with 120 or 240 is because from what I understand they can actually show the blu-rays in 24 frames am I correct? Yet in the description of the t it says it uses 3:2 pulldown. Isn't that when the tv corrects the frame rate to make it run at 30fps on 60HZ tvs?
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post #2 of 15
4/28/10 at 6:21pm
Look for a TV that does 24p or even 48p.
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post #3 of 15
4/28/10 at 9:51pm
Thread Starter 
Well the specifications say 24p Real Cinema mode with 3:2 pulldown
For accurate and realistic reproduction of film sources. So.....whats that mean?
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post #4 of 15
4/28/10 at 10:49pm
I really have no idea. It sounds like fancy marketing talk to me.

I did a google search on 24p Real Cinema

Found this nugget of info:

Quote:
"24p Real Cinema" is present in conjunction with "Intelligent Frame Creation" (IFC). It means that the TV runs at 96Hz for a 24p source and uses frame interpolation software to generate "made-up" frames between the actual frames in order to (theoretically) smooth out the motion, by reducing the effects of inherent film judder. This can be switched on or off.
Quote:
Some UK users who have the PZ85 or PZ800 models have found that the IFC feature produces an unnatural look for films on Blu-ray and have opted to keep it switched off. (That's why I settled for a PZ80B model rather than a more expensive PZ85B or PZ800B model.)
http://forum.blu-ray.com/display-the...e-rate-26.html

I'm still scratching my head on this one. But, I assume 24p playback is the way to go.
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post #5 of 15
4/28/10 at 10:53pm
Found some more discussions about this on other TVs.

http://www.avforums.com/forums/plasm...-playback.html

http://www.avforums.com/forums/plasm...-playback.html
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post #6 of 15
4/28/10 at 11:15pm
Thread Starter 
Hey, thanks guys.
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post #7 of 15
4/28/10 at 11:30pm
Hey Walt, if you're still curious about the differences I can go off on a bit of a tutorial if you want. You don't want 3:2 pulldown though...
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post #8 of 15
4/28/10 at 11:46pm
Tim Q, please do. This pulldown crap has been driving me crazy ever since I started shopping for a new Tv. TUTOR US, Tim!
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post #9 of 15
4/28/10 at 11:50pm
Thread Starter 
Quote:
Originally Posted by Timothy Q View Post
Hey Walt, if you're still curious about the differences I can go off on a bit of a tutorial if you want. You don't want 3:2 pulldown though...
No, please do...
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post #10 of 15
4/30/10 at 3:19pm
http://en.wikipedia.org/wiki/HDTV_blur

Quote:
One possible advantage of a 100 Hz + display is superior conversion of the standard 24 frame/s film speed. Usually movies and other film sources in NTSC are converted for home viewing using what is called 3:2 pulldown which uses 4 frames from the original to create 5 (interlaced) frames in the output. As a result 3:2 pulldown shows odd frames for 50 milliseconds and even frames for 33 milliseconds. At 120 Hz 5:5 pulldown from 24 frame/s video is possible[14] meaning all frames are on screen for the same 42 milliseconds. This eliminates the jerky effect associated with 3:2 pulldown called telecine judder. However, to use 5:5 pulldown instead of the normal 3:2 pulldown requires either support for 24 frame/s output like 1080p/24 from the DVD/HD DVD/Blu-ray Disc player or the use of reverse telecine to remove the standard 3:2 pulldown. Some TVs (particularly plasma models) do 3:3 pulldown at 72 Hz or 4:4 at 96 Hz.[15] (for specific models, see list of displays that support pulldown at multiples of the original frame rate.) PAL countries speed the 24 frame/s film speed by 4% to obtain 25 frame/s, therefore movies in the PAL format are completely free of Telecine judder effects.
And

http://en.wikipedia.org/wiki/Telecine
Quote:
The “2:3 pulldown” telecine process creates a slight error in the video signal compared to the original film frames that can be seen in the above image. This is one reason why films viewed on typical NTSC home equipment may not appear as smooth as when viewed in a cinema. The phenomenon is particularly apparent during slow, steady camera movements which appear slightly jerky when telecined. This process is commonly referred to as telecine judder. Reversing the 2-3 pulldown telecine is discussed below.

PAL material in which 2:3 pulldown has been applied, suffers from a similar lack of smoothness, though this effect is not usually called “telecine judder”. Effectively, every 12th film frame is displayed for the duration of three PAL fields (60 milliseconds), whereas the other 11 frames are all displayed for the duration of two PAL fields (40 milliseconds). This causes a slight “hiccup” in the video about twice a second. Increasingly being referred to as Euro pulldown as it largely affects European territories.
[edit] Reverse telecine (a.k.a. inverse telecine (IVTC), reverse pulldown)

Some DVD players, line doublers, and personal video recorders are designed to detect and remove 2-3 pulldown from telecined video sources, thereby reconstructing the original 24 frames/s film frames. This technique is known as “reverse” or “inverse” telecine. Benefits of reverse telecine include high-quality non-interlaced display on compatible display devices and the elimination of redundant data for compression purposes.

Reverse telecine is crucial when acquiring film material into a digital non-linear editing system such as Sony Vegas Pro, Avid, or Final Cut Pro, since these machines produce negative cut lists which refer to specific frames in the original film material. When video from a telecine is ingested into these systems, the operator usually has available a “telecine trace,” in the form of a text file, which gives the correspondence between the video material and film original. Alternatively, the video transfer may include telecine sequence markers “burned in” to the video image along with other identifying information such as time code.

It is also possible, but more difficult, to perform reverse telecine without prior knowledge of where each field of video lies in the 2-3 pulldown pattern. This is the task faced by most consumer equipment such as line doublers and personal video recorders. Ideally, only a single field needs to be identified, the rest following the pattern in lock-step. However, the 2-3 pulldown pattern does not necessarily remain consistent throughout an entire program. Edits performed on film material after it undergoes 2-3 pulldown can introduce “jumps” in the pattern if care is not taken to preserve the original frame sequence (this often happens during the editing of television shows and commercials in NTSC format). Most reverse telecine algorithms attempt to follow the 2-3 pattern using image analysis techniques, e.g. by searching for repeated fields.

Algorithms that perform 2-3 pulldown removal also usually perform the task of deinterlacing. It is possible to algorithmically determine whether video contains a 2-3 pulldown pattern or not, and selectively do either reverse telecine (in the case of film-sourced video) or deinterlacing (in the case of native video sources).
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post #11 of 15
5/4/10 at 12:17am
In layman's terms... 120hz refreshes every frame of film 5 times (think of it as division, 120/24 = 5) but 60hz refreshes some frames 3 times and some 2 because 60/24 is an uneven amount. What this results in is a "jutter" because some frames appear a fraction longer than others. 3:2 pulldown more or less blurs some frames to make this "jutter" less noticeable.

If you would like a true representation of your 24 frames per second film you should go with a 120hz television and skip the pulldown. Also, turn off the bells and whistles that smooth out film's natural flicker at 24fps. It's the reason all those 120hz TV's you see in stores look like they're showing weird video instead of movies. They leave those settings on and it basically smooths out the film's flicker thus giving it a 30fps video look instead.

Hope that helped. Sorry it took so long!
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post #12 of 15
5/4/10 at 2:56am
Thread Starter 
Quote:
Originally Posted by Timothy Q View Post
In layman's terms... 120hz refreshes every frame of film 5 times (think of it as division, 120/24 = 5) but 60hz refreshes some frames 3 times and some 2 because 60/24 is an uneven amount. What this results in is a "jutter" because some frames appear a fraction longer than others. 3:2 pulldown more or less blurs some frames to make this "jutter" less noticeable.

If you would like a true representation of your 24 frames per second film you should go with a 120hz television and skip the pulldown. Also, turn off the bells and whistles that smooth out film's natural flicker at 24fps. It's the reason all those 120hz TV's you see in stores look like they're showing weird video instead of movies. They leave those settings on and it basically smooths out the film's flicker thus giving it a 30fps video look instead.

Hope that helped. Sorry it took so long!
Alright see thats what I thought. I always heard 3:2 pulldown is when the tv takes a 24fps signal and converts it to 30fps so it can run on a 60hz set which is what my tv does now. What caused my confusion is the tv I listed is 120hz yet still says it uses 3:2 pulldown. Thanks.
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post #13 of 15
5/4/10 at 5:20pm
Wow... sorry Walt, totally spaced out there because I let it go a few days.

I think what you're seeing there is a Best Buy copy/paste mistake. They seem to be describing an LG 60hz in that section, as the actual LG site says nothing of 3:2 pulldown on that model (which makes sense) and "Real Cinema" isn't mentioned either.
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post #14 of 15
5/4/10 at 6:46pm
Quote:
Originally Posted by Timothy Q View Post
If you would like a true representation of your 24 frames per second film you should go with a 120hz television and skip the pulldown. Also, turn off the bells and whistles that smooth out film's natural flicker at 24fps. It's the reason all those 120hz TV's you see in stores look like they're showing weird video instead of movies. They leave those settings on and it basically smooths out the film's flicker thus giving it a 30fps video look instead.
This drives me fucking nuts It always looks like they're playing a BBC movie of the week based on a Jane Austin novel.
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post #15 of 15
5/5/10 at 3:51am
Thread Starter 
Quote:
Originally Posted by Timothy Q View Post
Wow... sorry Walt, totally spaced out there because I let it go a few days.

I think what you're seeing there is a Best Buy copy/paste mistake. They seem to be describing an LG 60hz in that section, as the actual LG site says nothing of 3:2 pulldown on that model (which makes sense) and "Real Cinema" isn't mentioned either.
Thanks.
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