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"Moire" Patterns on Blu-ray? (1 Viewer)

Cinescott

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Every once in a great while, I will get a "shimmering" effect on my screen when watching a Blu-ray. It tends to happen on surfaces that have a very fine pattern, such as on an old-style suit or a screen fence. Does anyone else experience this??? I noticed it recently on my "Twilight Zone" set, since many of the characters have very finely detailed suits.

I have a Samsung 55" LED display and my Blu-ray player outputs at 1080p24. My sharpness setting is set to "0" and I have all post-processing features on my TV set to "off".

It's not a frequent occurrence and I don't think it's the result of any artificial sharpening on the Blu-ray itself. The reason I am confused is I thought progressive video was supposed to end this rather annoying anomaly forever, but it still seems to be a rare plague for me.
 

schan1269

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By the way, one way to reduce the shimmer on an LCD is to switch your BD player to 1080i...if your LCD will show i without deinterlacing.
 

Johnny Angell

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First of all, I'm no expert on moire patterns, but I believe it is a product of using dots or pixels to represent an image. If you use a scanner with your pc, your scanner software likely has a moire reduction setting which can occur when you are scanning an image the consists of dots and the scanner is in turn reproducing the image as a collection of dots or pixels.

So think of scanning an image made of dots as reproducing a complex image. You can get moire. Think of a TV camera as scanning an image and when the image is complex (like a pattern on a suit or a screen door), then your TV tries to reproduce it and you get moire.

I seldom see it on my Samsung es7100, but when I do, it's because someone is wearing a shirt they shouldn't wear on tv. :)
 

Peter Apruzzese

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schan1269 said:
Shimmering is a defect of LCD displays. Part of their inherent flaw of sucking at motion.
It's also baked into some transfers, see "To Catch a Thief".
 

Persianimmortal

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I'm no expert, but as I understand it, different displays (and different output modes on each display) handle image processing differently. Unintentional defects such as moire effects can result from different processing algorithms used to adjust the image quality, and/or if any rescaling is occurring. In other words, the amount of moire (if any) you are seeing is largely display-dependent.

Peter Apruzzese said:
It's also baked into some transfers, see "To Catch a Thief".
I don't think the Blu-ray of To Catch a Thief has any built-in moire.

The screencap below is one I just took from the Blu-ray, and is a scene that I recall usually exhibited a lot of moiring when I used the DVD version years ago. If you click to view the full-size image, you can see the lines on Cary Grant's top are clearly delineated. But try the following while the full-sized image is showing: resize your browser window, or drag the browser window around. I'm sure most people will instantly see some moiring. In fact some moiring is visible on the rescaled thumbnail shown below.



For example, this is what I see when I reduce the image in Windows Photo Gallery, on my 24" Samsung PC monitor (image shown at actual size):

tIeJ4Uz.jpg



That is the result of the way your display (or the software that rescales the images) is handling the image, not any "baked in" moiring on the image. Better quality Blu-ray players and displays, and turning off scaling options such as Overscan, should reduce or eliminate most moiring.
 

Peter Apruzzese

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Persianimmortal said:
I'm no expert, but as I understand it, different displays (and different output modes on each display) handle image processing differently. Unintentional defects such as moire effects can result from different processing algorithms used to adjust the image quality, and/or if any rescaling is occurring. In other words, the amount of moire (if any) you are seeing is largely display-dependent.



I don't think the Blu-ray of To Catch a Thief has any built-in moire.

The screencap below is one I just took from the Blu-ray, and is a scene that I recall usually exhibited a lot of moiring when I used the DVD version years ago. If you click to view the full-size image, you can see the lines on Cary Grant's top are clearly delineated. But try the following while the full-sized image is showing: resize your browser window, or drag the browser window around. I'm sure most people will instantly see some moiring. In fact some moiring is visible on the rescaled thumbnail shown below.



For example, this is what I see when I reduce the image in Windows Photo Gallery, on my 24" Samsung PC monitor (image shown at actual size):




That is the result of the way your display (or the software that rescales the images) is handling the image, not any "baked in" moiring on the image. Better quality Blu-ray players and displays, and turning off scaling options such as Overscan, should reduce or eliminate most moiring.
Very interesting, thanks for this information. I can see minor moire on this cap on my iPad Retina (not bad, but there), but it's very noticeable on my PC monitor when doing as you suggested. Will have to re-evaluate To Catch a Thief on the big rig now that I've got a new screen built.
 

schan1269

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"Is this something 4K would eliminate or reduce since there would be more pixels?"

4K LCD, no.

4K OLED, maybe*.

4K plasma(if there were any), maybe*.

*Since, for OLED and plasma, the pixel is the light source, if the pixels get small enough Moire could go away. 4K projection**, the projectors, in theory, would have to grow in size to make the image source to screen a smaller ratio.

**OLED will render projection a moot point.
 

Persianimmortal

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I'm not going to be quite as bold as Sam above and say that OLED will render projection moot :)

But more pixels from 4K will reduce moiring due to greater accuracy in displaying fine lines, yes.

What it won't necessarily do is eliminate moiring from rescaling, or other image processing. For example, on current 1080p displays, you will get much greater moiring and other artifacts when playing a DVD, because it always has to be upscaled (to fit a 640x480 image onto a 1920x1080 display). Using Blu-ray automatically reduces the potential for moiring, as it is native 1080p content which isn't rescaled.

Similarly, if you have a 4K display, but mainly play upscaled 1080p Blu-ray content, I suspect there is the potential for moiring and other scaling issues. Using native 4K content should resolve that.

Then of course, it also depends on what image processing the 4K Blu-ray player and/or the 4K TV are performing. Certain types of motion handling methods may result in moiring - I don't really know as obviously few of us have actually seen 4K content on a 4K display.

It would be nice if one of the TV pros like David Mackenzie could pop in and answer some of these questions :)
 

bryan4999

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My personal experience is that I get quite a bit of moire on my Samsung 50" that I use for casual viewing in the family room (drives me nuts), but I have never had even one instance of it on my Optoma projector (projected at about 110"), including To Catch a Thief.
 

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