Question 2-3 pulldown, 1080p24, 60Hz + 120Hz displays - Questions

[kazinvan]

I have been trying to get a better understanding of this 2-3 pulldown issue and have read a few articles and posts that discuss it. The reason I'm looking into it is because I'm looking to buy a new TV and I was looking at the Sony SXRD KDS-60A2020. Having seen it in the store, the display looks great but it still suffers from the "judder" during pans and other motion sequences. I guess my confusion comes from where the real problem is.

I see that some display devices can accept a 1080p24 signal, but how does that help? Doesn't that display still need to somehow convert the 24fps signal into 60fps? Isn't that where the problem comes in? I don't see why it makes a difference if the display does it or if the DVD player does it, or something else does it. From what I can tell, the source needs to be converted *somewhere* along the way.

I see that the new Sony SXRD TVs are supposed to have the 24fps input and 120Hz display, correct? If so, does that eliminate the whole 2-3 pulldown issue? I know that 120 divides evenly by 24 which means there is no weird adding/removing frames.

In the end, I'm trying to decide if it's worth waiting for one of the new SXRD models or not. This seems to be a big improvement in quality since I really notice the judder and would love to get a TV that is not affected.

The other question is will you need a DVD player capable of sending the TV 24fps? I have an HD-A2 and don't want to replace it if I don't have to.

Thanks for the help

 

[MDS]

II see that the new Sony SXRD TVs are supposed to have the 24fps input and 120Hz display, correct? If so, does that eliminate the whole 2-3 pulldown issue? I know that 120 divides evenly by 24 which means there is no weird adding/removing frames.

With the new TVs that use 120 Hz, each frame is shown 5 times and supposedly that eliminates some of the problems with 2-3 pulldown when the image is changing quickly because it is just duplicating the same frame rather than showing one frame twice and the next three times.

I've only seen one review of a 120 Hz TV (new Sharps) and the reviewer said he didn't really notice any difference between it and its predecessor that was 60 Hz.

 

[kazinvan]

With the new TVs that use 120 Hz, each frame is shown 5 times and supposedly that eliminates some of the problems with 2-3 pulldown when the image is changing quickly because it is just duplicating the same frame rather than showing one frame twice and the next three times.

I've only seen one review of a 120 Hz TV (new Sharps) and the reviewer said he didn't really notice any difference between it and its predecessor that was 60 Hz.

Any chance you remember where that review was?

I suppose it matters what the source is doing as well, if the DVD player is sending 1080i 30fps then it probably doesn't make a difference as the 2-3 pulldown has already taken place, right?

I'm assuming you would need to send 24fps to the TV in order for the 120Hz display to make any difference. Correct me if I'm wrong here.

 

[MDS]

I don't recall the source of the review but you may be able to find it if you Google 'sharp d82u' because the d82u/d92u series is the new series with 120 Hz refresh rates.

2-3 pulldown is only necessary when the source is film and therefore 24 fps. If the source is video and 30fps (actually 29.97 for NTSC) then a normal 60 Hz display will simply display each frame twice. The 120 Hz TV will display each frame 4 times.

 

[kazinvan]

I don't recall the source of the review but you may be able to find it if you Google 'sharp d82u' because the d82u/d92u series is the new series with 120 Hz refresh rates.

2-3 pulldown is only necessary when the source is film and therefore 24 fps. If the source is video and 30fps (actually 29.97 for NTSC) then a normal 60 Hz display will simply display each frame twice. The 120 Hz TV will display each frame 4 times.

I think you may be referring to this review:

"My hopes of Sharp's 120-Hz imaging eliminating the judder introduced when processing 24-fps video were dashed when I could discern no difference between it and traditional 60-Hz displays. But viewing the same content on the Pioneer PRO-940HD plasma television with its 72-Hz (3x24) display function resulted in impressively smooth (judder free) panning shots in our favorite movies."

http://www.pcmag.com/article2/0,1895,2102097,00.asp

So what is the point if 120Hz doesn't reduce judder when displaying 24fps? There must be more to this than 2-3 pulldown.

 

[avaserfi]

Ive sat side by side with the 60hz sharp and the 120hz sharp. I couldn't see a difference, not one worth the money atleast. The latter sharp was slightly better but as a gamer I still didn't see it worth the extra money. I own the new model of the 60hz 42inch sharp (see my sig) and that thing works wonders. I never see trails or have any "common" lcd problems, even after ordering it online.

 

[mfabien]

You might want to read about the following feature on the Pioneer Plasma models PDP-5070HD and PDP-6070HD:

Pure Drive II Signal Processing – Full time 10-bit Digital Video Processing delivers a low noise, high contrast, natural colored image1080p/24Hz Compatibility for HDMI and Component

Now both TV's have a native resolution of 1365 x 768 and therefore display in 768p.

Both HD DVD and BD movies have 1080p/24fps data as data source for movies. But players for both are sending either 1080i/60 fps or 1080p/60 fps.

My understanding is that these Pioneers are able to process the data based on the source, which is 1080p/24 Hz. The fact that the Video Processor can do this, even using Component (not capable of receiving a 1080p signal), supports this.

Note: When the HD XA2 was introduced, there were discussions about a possible upgrade down the road to enable 1080p/24 fps signal delivery. But at this time, that remains at 1080p/60 fps.

 

[BMXTRIX]

The PS3 can deliver 1080p/24 Blu-ray content as well with the most recent firmware update.

On subject: The concept is simple, if you aren't feeding a display a 24hz source material, then you aren't going to see a proper difference, and most gamers aren't feeding 1080/24p content. They are starting with native progressive content and feeding it at accurate frame rates most often.

So, a properly implemented 120hz set should be able to deliver full quality 1080/24p as well as 1080i native content without any issues and if the processing is good for non-HD titles, then the video should look awesome.

 

[mr-ben]

Having seen it in the store, the display looks great but it still suffers from the "judder" during pans and other motion sequences. I guess my confusion comes from where the real problem is.

When I watch something that runs at 24fps, such as movies, Pans and fast motion appears to not be "smooth" - the movement is in chunks across the screen and not a smooth transition across like most TV shows. As far as I know, this is simply because 24fps is too slow of a frame rate, and we can see the gaps between frames. 60fps is close to where fast movement becomes smooth. I get the same feeling when I'm in the movie theater, which runs at 24fps. This is different from the 2:3 pulldown stuff. Are you sure that you're actually seeing a problem?