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Discussion Starter · #1 ·
I have DVE Blu ray edition and I was wondering if anyone knows of a pattern there or anywhere that will see if you Tv shows visible dithering. Thanks.
 

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You'll most easily see dithering on a black field/window if your black level is set too high. Set black level just below the point of dithering.
 

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There is also a moving circle/bar pattern on Avia Pro (can't remember if it's on AviaII as well) taht is useful for dithering/posterization on DLPs during fast motion.
 

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Here's a classic example of people interpreting the question differently.


I was going to answer that you want to look for a crossed ramps pattern to see the effects of dithering across the entire greyscale.


To the OP, what exactly are you looking for?
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by jvincent /forum/post/15532717


Here's a classic example of people interpreting the question differently.


I was going to answer that you want to look for a crossed ramps pattern to see the effects of dithering across the entire greyscale.


To the OP, what exactly are you looking for?


I am actually still learning what these more advanced PQ terms mean......dithering.....posterization......banding.....false contouring...


And I believe that some of those terms are used interchangeably. I had read that dithering will show up as noise in dark areas especially. So I was wondering if there was a test pattern for dithering besides eyeballing dark areas/patterns. I have a 9G Pioneer and the black levels are pretty solid and uniform. But I do notice that when brightness is raised that the in a PITCH black room, that you can see the noise or slight unevenness in the black level. But as I lower the brightness down to the neutral level that I keep it at (+1), I see that "noise" disappear.


Also......what should I be looking for in the

in terms of the continuous horizontal transition from white to black at the top and bottom of the pattern. It looks like a smooth transition mainly, but with my eagle eyes (I have well above average eyesight) and my 50 in. panel being 8 feet away.....I can make out tons of miniscule vertical lines that the transition is composed of. They are subtle and hard to see from my seating distance, but when I move closer I can just make them out. And there are LOTS of them.

Thanks.
 

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OK, so there are a few pieces to what you have described.


The first is the algorithm that the panel uses specifically for low intensity signals. My panel has 3 of them and I prefer setting "3", which I believe is the error diffusion algorithm. This is best set after setting contrast/brightness.


In terms of how to set those if you use the various calbration DVDs or BluRay there are patterns that include several low percent stimulus bars (1%, 2%, etc) that you use to set your brightness. The idea here is to be able not see black (0%) and see 1% and up.


The second thing you mention is what I was referring to with the crossed ramps pattern. As you vary contrast/brightness/gamma (and a whole bunch of other controls) you will often see very different behaviours in a crossed ramp pattern. Coloured banding is the most noticeable effect.


On my particular plasma I can see fairly dramatic changes by adjusting the contrast and/or brightness by only a couple of clicks.


This is why whenever I think I am "done" I always go back to that pattern to check for a uniform ramp and make small adjustments as needed.
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by jvincent /forum/post/15535613


OK, so there are a few pieces to what you have described.


The first is the algorithm that the panel uses specifically for low intensity signals. My panel has 3 of them and I prefer setting "3", which I believe is the error diffusion algorithm. This is best set after setting contrast/brightness.


In terms of how to set those if you use the various calbration DVDs or BluRay there are patterns that include several low percent stimulus bars (1%, 2%, etc) that you use to set your brightness. The idea here is to be able not see black (0%) and see 1% and up.


The second thing you mention is what I was referring to with the crossed ramps pattern. As you vary contrast/brightness/gamma (and a whole bunch of other controls) you will often see very different behaviours in a crossed ramp pattern. Coloured banding is the most noticeable effect.


On my particular plasma I can see fairly dramatic changes by adjusting the contrast and/or brightness by only a couple of clicks.


This is why whenever I think I am "done" I always go back to that pattern to check for a uniform ramp and make small adjustments as needed.

Thank you very much for the answer. I have also read the REC 709 description of the gray ramps and steps as well as the explanation on the DVE BR disc, and I feel quite satisfied that the panel is performing at a high level. On the ramps it is a smooth transition with no noticeable stepping or uneven increases in brightness change, and if you get up closer you can begin to see seperation between the shades of gray....feint, but there.


The steps are beautiful, without a hint of color creeping in. It is also passing WTW 253, so that is a good thing.
 
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