24p playback without 2:3 pulldown

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xell17

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Oct 9, 2014
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So I bought an Asus VG278HE (144Hz) recently and to my great disappointment 24p content played at 48Hz/72Hz/96Hz via HDMI/DVI and PC still had horrible motion judder.
I do know that while a lot of monitors accept those refresh rates, they still do that with a 2:3 pulldown,
Is the VG278HE also one of those or am I doing something wrong? I tried googling it but there's not really a lot info about it.
Are there any monitors (20-30" range) at all that support proper 24p playback or do I have to opt for a TV?

Thanks in advance.
 
What video players are you using? I've used MPC and more recently, mpv, without issue on similar monitors. Flash streaming videos are problematic. Some fast pans still look terrible because 24Hz simply isn't enough, especially on a monitor with fast pixel response times.
 
I'm using MPC + madVR. The movie I used was RED (2010). There is a scene at 4:05 where the camera pans around the neighborhod that is almost unwatchable at 60Hz. Playing it back at 144Hz looked IMO even worse due to (as I suspect) the monitor reverting it internally back to 60Hz.
 
Are you sure the judder you're seeing is introduced by a pulldown process, or is the judder actually inherent to what was shot? Have you tried MadVR with its "smooth motion" option enabled?
 
I know that shot in Red - it's the fault of the director/cinematographer. Nothing you can do, the judder is because they panned at the wrong rate for 24 frames per second. Usually moviemakers are careful not to make newb mistakes like that. :)
 
BTW a good test for 24p playback are the Lord of the Ring movies. I especially like The Two Towers, where the camera pans up the model of Baradur - easy to spot 3:2 pulldown judder or glitches when you don't have the refresh rate set exactly right.
 
Run your monitor at 24hz to match the source and you will not have to deal with wondering if its you or the cinematographer. If your monitor cant go that low then just run it at something evenly divisible by 24, such as 120.

MPC-HC + madvr can actually automatically change your monitors refresh rate on the fly to match the movie you play back, but to start you can just do it manually.
 
The VG278HE panel will run at 120Hz if you select a refresh that is less. It is a peculiar behavior and is explained in the TFT Central review. The only thing that changes is the PWM frequency which can become unbearable. Beyond that this monitor does not support any refresh rate lower than 60Hz.

120/144Hz should still be fine with 24Hz content, though. I know that Corel WinDVD has a set of options that you need to change to get 24Hz content to play back correctly, which includes the ability to disable 3:2 pulldown if your monitor's refresh rate is a multiple of 24. I have not experienced any judder using Corel WinDVD 10/11 with this monitor.
 
How would 24fps judder look? The main thing annoying me is flickering/flashing of still objects while the camera pans. The madvr option "Smooth motion" seems to smoothen the camera pan motion itself while the flickering/flashing of the object remains.

edit: After googling like a mad man I found this post by Richard Berg on arstechnica.com:

"There are two kinds of judder associated with film source (24fps) material.

1) telecine judder, introduced by splitting each frame into fields and repeating some of them in a 3:2 pattern
2) motion capture judder, introduced by the fact that the objects in front of the camera moved too quickly for the low sampling rate to fool our visual acuity

120hz displays can eliminate #1 by displaying 24fps material with 5:5 pulldown, instead of the 3:2 pattern required to squeeze 24 frames onto a 60Hz display. However, a 120hz display is not strictly required. For example, my projector displays 24fps material at 96Hz; computer monitors can be figured to sync at any frequency you like.

Many recent displays (virtually all 120hz-ers, some others) also have the ability to digitally interpolate extra "in-between" frames. This is designed to make effect #2 less noticeable, though film purists will hate it. Unlike solutions to #1, which restore the image to the exact form it was filmed, there is no way to solve issue #2 without changing the framerate at which we shoot film. Unfortunately film is a very old & established format. That's why HDTV video, computer graphics, videogames, etc are rendered at 60fps or higher."

Mind you this post is from 2009. Is this still the case? The problem I was trying to solve was actually not caused by an uneven pulldown but an inherent problem with 24p (the so called 24p judder?) and is only solvable by motion interpolation?
 
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24p will look pretty smooth, not silky smooth mind you, unless there's something moving at high speed. If you want everything you watch to look like a soap opera, use interpolation.

144hz and 120hz will not have pulldown with 24p content, as the framerate is divisible by 24.
 
xell17 said:
How would 24fps judder look? The main thing annoying me is flickering/flashing of still objects while the camera pans. The madvr option "Smooth motion" seems to smoothen the camera pan motion itself while the flickering/flashing of the object remains.

edit: After googling like a mad man I found this post by Richard Berg on arstechnica.com:

"There are two kinds of judder associated with film source (24fps) material.

1) telecine judder, introduced by splitting each frame into fields and repeating some of them in a 3:2 pattern
2) motion capture judder, introduced by the fact that the objects in front of the camera moved too quickly for the low sampling rate to fool our visual acuity

120hz displays can eliminate #1 by displaying 24fps material with 5:5 pulldown, instead of the 3:2 pattern required to squeeze 24 frames onto a 60Hz display. However, a 120hz display is not strictly required. For example, my projector displays 24fps material at 96Hz; computer monitors can be figured to sync at any frequency you like.

Many recent displays (virtually all 120hz-ers, some others) also have the ability to digitally interpolate extra "in-between" frames. This is designed to make effect #2 less noticeable, though film purists will hate it. Unlike solutions to #1, which restore the image to the exact form it was filmed, there is no way to solve issue #2 without changing the framerate at which we shoot film. Unfortunately film is a very old & established format. That's why HDTV video, computer graphics, videogames, etc are rendered at 60fps or higher."

Mind you this post is from 2009. Is this still the case? The problem I was trying to solve was actually not caused by an uneven pulldown but an inherent problem with 24p (the so called 24p judder?) and is only solvable by motion interpolation?
Click to expand...

This is a so late reply but i found this thread after searching about judder. Could you find any solution for "red" movie 04:05 panning scene? Yes it can be smooth with frame interpolation but other ways, no. i am using 120hz monitor, using reclock to make movie 23.976 to 24fps. So 120/24 is fine, but i still see judder of godness at 04:05 (without frame interpolation)
 
24p requires frame interpolation to look smooth.
Refreshing at a multiple of 24 rather than 60 just removes an additional type of judder. It doesn't fix the low framerate.
 
xell17 said:
How would 24fps judder look? The main thing annoying me is flickering/flashing of still objects while the camera pans. The madvr option "Smooth motion" seems to smoothen the camera pan motion itself while the flickering/flashing of the object remains.

edit: After googling like a mad man I found this post by Richard Berg on arstechnica.com:

"There are two kinds of judder associated with film source (24fps) material.

1) telecine judder, introduced by splitting each frame into fields and repeating some of them in a 3:2 pattern
2) motion capture judder, introduced by the fact that the objects in front of the camera moved too quickly for the low sampling rate to fool our visual acuity

120hz displays can eliminate #1 by displaying 24fps material with 5:5 pulldown, instead of the 3:2 pattern required to squeeze 24 frames onto a 60Hz display. However, a 120hz display is not strictly required. For example, my projector displays 24fps material at 96Hz; computer monitors can be figured to sync at any frequency you like.

Many recent displays (virtually all 120hz-ers, some others) also have the ability to digitally interpolate extra "in-between" frames. This is designed to make effect #2 less noticeable, though film purists will hate it. Unlike solutions to #1, which restore the image to the exact form it was filmed, there is no way to solve issue #2 without changing the framerate at which we shoot film. Unfortunately film is a very old & established format. That's why HDTV video, computer graphics, videogames, etc are rendered at 60fps or higher."

Mind you this post is from 2009. Is this still the case? The problem I was trying to solve was actually not caused by an uneven pulldown but an inherent problem with 24p (the so called 24p judder?) and is only solvable by motion interpolation?
Click to expand...

Yes. Watching 24fps on sample and hold display (any LCD that is) results in stuttery motion and only way to ger around it is either add light amounts of motion interpolation (just a bit to avoid soap opera look and minimize artifacts) or add low enough backlight scanning that introduces visible flicker. Visible CRT like flickering fools our eyes to make motion appear smoother and judder free. Film purist talking about "film look" are IMHO talking out of their asses because this juddering mess they are defending is NOT what we saw during CRT days when 24fps format was born.
 
MaZa said:
Yes. Watching 24fps on sample and hold display (any LCD that is) results in stuttery motion and only way to ger around it is either add light amounts of motion interpolation (just a bit to avoid soap opera look and minimize artifacts) or add low enough backlight scanning that introduces visible flicker. Visible CRT like flickering fools our eyes to make motion appear smoother and judder free. Film purist talking about "film look" are IMHO talking out of their asses because this juddering mess they are defending is NOT what we saw during CRT days when 24fps format was born.
Click to expand...
The issue is just as present on a CRT, unless you're running it at 24Hz.
If anything judder is worse on an impulse-type display running at some multiple of 24, since you end up with duplicated frames and double-images.

You're absolutely right about the current presentation of 24p not being how it was intended to look though.
If you display 24p at 24Hz on a CRT, motion looks just as fluid as displaying 24p on a sample-and-hold display with interpolation enabled.
So ironically, interpolation is actually closer to the original look for film, not further from it as "purists" insist.
 
MaZa said:
Yes. Watching 24fps on sample and hold display (any LCD that is) results in stuttery motion and only way to ger around it is either add light amounts of motion interpolation (just a bit to avoid soap opera look and minimize artifacts) or add low enough backlight scanning that introduces visible flicker. Visible CRT like flickering fools our eyes to make motion appear smoother and judder free. Film purist talking about "film look" are IMHO talking out of their asses because this juddering mess they are defending is NOT what we saw during CRT days when 24fps format was born.
Click to expand...

When you're using the correct refresh rate 24p films look the same way on a lcd and on a crt, i'm not convinced that lcd blurs at 24p.
 
MaZa said:
Yes. Watching 24fps on sample and hold display (any LCD that is) results in stuttery motion and only way to ger around it is either add light amounts of motion interpolation (just a bit to avoid soap opera look and minimize artifacts) or add low enough backlight scanning that introduces visible flicker. Visible CRT like flickering fools our eyes to make motion appear smoother and judder free. Film purist talking about "film look" are IMHO talking out of their asses because this juddering mess they are defending is NOT what we saw during CRT days when 24fps format was born.
Click to expand...

24p is a film format, nothing to do with CRTs. And while film projectors flicker, they don't flicker at 24hz, so they are both holding and repeating images.
 
Luke M said:
24p is a film format, nothing to do with CRTs. And while film projectors flicker, they don't flicker at 24hz, so they are both holding and repeating images.
Click to expand...
Yes, so modern projectors which repeat frames have the same problem.
When you view film at 24Hz on an impulse-type display or project it at 24Hz, you get perfectly sharp and fluid motion without any judder. The problem with native 24Hz is that you get significant flicker, which is much worse at the typical brightness levels that modern displays operate at.

Interpolation preserves the native 24Hz look without adding flicker. Instead of flicker, you get interpolation errors instead.

leadays said:
When you're using the correct refresh rate 24p films look the same way on a lcd and on a crt, i'm not convinced that lcd blurs at 24p.
Click to expand...
Sample-and-hold displays blur the image more and more the lower the framerate gets, so there is a lot of motion blur present on an LCD which is not there on a CRT.
 
zone74 said:
Interpolation preserves the native 24Hz look without adding flicker. Instead of flicker, you get interpolation errors instead.
Click to expand...

I can see how interpolation allows for flicker and judder free presentation, but I don't see how it preserves the native 24 hz look. If you're running @ 60 hz and interpolating, it's going to look like 60 fps, which is a much different feel than 24 fps.
 
spacediver said:
I can see how interpolation allows for flicker and judder free presentation, but I don't see how it preserves the native 24 hz look. If you're running @ 60 hz and interpolating, it's going to look like 60 fps, which is a much different feel than 24 fps.
Click to expand...
Native 24Hz on a CRT looks ridiculously smooth compared to 48Hz or higher. As soon as you start repeating frames, motion in 24p sources looks like crap.
At 24Hz on a CRT it looks as fluid as interpolation does on a sample-and-hold display. It's really shocking how big the difference is when you view 24p at 24Hz.
 
Yes, I get that (would love to experience it for myself, but I don't think I have a CRT capable of 24 hz).

My question still stands though. How can interpolation preserve the native 24 hz look? What refresh rate are we talking about here?
 
spacediver said:
Yes, I get that (would love to experience it for myself, but I don't think I have a CRT capable of 24 hz).

My question still stands though. How can interpolation preserve the native 24 hz look? What refresh rate are we talking about here?
Click to expand...
With a CRT you can also use black frame insertion to reduce the effective refresh rate from 48/72/96Hz to 24, since a black frame doesn't attempt to draw anything on the display with a CRT. (assuming you have the brightness control set so that black=off)
With a non-CRT display, black frame insertion doesn't really work because it has to draw a black frame, which means you have slow response times to deal with.

Interpolation is a tool to remove judder, it does not increase the native framerate of the video.
24p interpolated to 120 FPS does not look like a 120 FPS native source. You don't have the temporal resolution, and you still have all that motion blur from shooting with a 1/48s shutter.
24p interpolated to 120 FPS does, however, look very much like 24p displayed at 24Hz on a CRT.
I know it's difficult to believe, but raw 24p really does look that smooth on a CRT at 24Hz.

Displaying 24p on a sample-and-hold display, or at 48Hz or higher on an impulse-type display doesn't just add a small amount of judder. It's the difference between the perfectly fluid motion that you get with interpolation and the juddering crap that "purists" seem to love.
 
Ah, right the black frame insertion. Someone posted some code up on blurbusters for doing that. I might give it a shot.

I'm still confused about interpolation. Perhaps I'm misunderstanding what you mean by interpolation.

Here's my mental model.

Source = 24p.
Display = sample and hold, running @ 120hz
Software interpolates an extra four frames between the source frames, so that there are now 120 unique images per second.

End result = smooth, judder free appearance.

BUT it would have that 120 fps feel (which some feel is soap opera like).

Are you saying that raw 24p on a 24 hz CRT also has that soap opera effect?

Also, what would 24p on a 24 hz sample and hold display look like? Smooth but blurrier?
 
spacediver said:
Are you saying that raw 24p on a 24 hz CRT also has that soap opera effect?
Click to expand...
Yes - though I think it's a misnomer to call it a "soap opera effect" since that term is not used favorably.
People that use it often say that natively high-framerate sources look bad too - so their issue is not the interpolation, but a lack of judder.

spacediver said:
Also, what would 24p on a 24 hz sample and hold display look like? Smooth but blurrier?
Click to expand...
Well that's what I would have thought, but I guess at some point persistence just becomes too long for your eye to be fooled into thinking that the motion is smooth - because it always seems to judder badly on the sample-and-hold displays that I've seen.
Now technically those were refreshing at 120Hz but since they're sample-and-hold that should theoretically be identical to 24Hz.
 
cool, thanks for the patient clarifications. And yep, agreed on the soap opera misnomer.
 
zone74 said:
Yes, so modern projectors which repeat frames have the same problem.
When you view film at 24Hz on an impulse-type display or project it at 24Hz, you get perfectly sharp and fluid motion without any judder.
Click to expand...

Even the original film projectors that flickered at 24hz held the image as long as possible (e.g. 50%) to minimize light waste.
 
This GIF shows well what the effect of flickering/BFI has on motion smoothness.
http://abload.de/img/bfim7pzn.gif

Both refresh at the same speed but bottom one looks so much more fluid in human eyes even at such a low framerate made for the presentation purposes. My argument was that the bottom was what we were originally supposed to see be it from film or through CRT, not the top one which we see today without interpolation.
 
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