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Discussion Starter · #1 ·
Ok,


Since my other thread appears to have been hijacked by the "My cables are better than your cables" crew, I figured I would continue to post my observations on the new HLN617W.


I walked right up to the tv with it turned off and examined the screen. I noticed the pattern of "grain" on the screen and this is indeed exactly what I notice when watching any video content. This somewhat concerns me. Why is the screen not perfectly smooth? I know absolutely nothing about protective screens and stuff of that sort, but it seems that this is a little silly to have something that isn't uniformly smooth.


Thoughts? Am I on drugs? Did I forget to remove some sort of film from the screen or something?


Later,

Jeff
 

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Coyote Waits
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What is the maximum distance that you can see the pattern on the screen? I had a HLM507 for a month and didn't notice what you are seeing. There are threads where screen design gets a thorough going over but I'm sorry to say I can't remember where.


The grooved surface may have something to do with the "non-glare" characteristic of Samsung and Panasonic DLP screens.
 

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You may want to play with the gamma setting and the different component inputs and send it interlaced/progressive signal. I understand that the set does deinterlacing/line doubling pretty well, supposedly the best. But I found that the PQ is a lot less grainy if I let my Panny DVD player send the progressive signal. Maybe it's because it's a lot more forgiving that way?


Anyway, the picture is very nice now.
 

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Boy I had just decided to make the move from HLM507 to the new HLN61. This issue is causing some concern. I guess in the end based on your experience so far I would be interested in if you would recommend the move to the new HLN? It is a $1000 move so it is not a no brainer for me.
 

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Discussion Starter · #5 ·
Quote:
Originally posted by chriscal
Boy I had just decided to make the move from HLM507 to the new HLN61. This issue is causing some concern. I guess in the end based on your experience so far I would be interested in if you would recommend the move to the new HLN? It is a $1000 move so it is not a no brainer for me.
chriscal,


I can't in good conscience recommend you go one way or the other as I JUST got the set yesterday and really haven't had a chance to put it through it's paces. Peraonlly, if you CAN wait, I would put off the decision until we have a nice cross section of people that actually OWN and use this set alot before making your decision. Thus far these are my knee-jerk reactions to the out of the box performance. Once we get lots of people posting tweaks and stuff of that nature... THEN you can make a more informed decision. Don't just trust the off hand comments of one schmuck like me. I may just be asking for more than this tv can deliver based on my being "spoiled" by the 36" direct view hdtv I have as well.


Now... onto another thing that pisses me off. The DTC100 and the PC input on this tv are NOT good friends. I keep losing sync with the two devices and have to go in a tweak the raster centering in the DTC100 to get it to stop freaking out. I'm just glad that I plan on using the TS-160 STB instead of the DTC100 or I would be more peeved.


Later,

Jeff
 

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Discussion Starter · #6 ·
Well, I could very well have been on crack these last few days. Instead of just wondering if it was the screen causing what I thought was video graininess, I actually PAUSED a scene on the DVD player when it came to a place I thought that illustrated the graininess. Guess what... I am a moron!


Turns out, it's actually the MPEG artifacts that I am seeing... not the screen. Weird how you never notice this stuff on a 36" picture from 10 feet away but notice it BIGTIME on a 61" picture from 12-13 feet away.


Ok, so mystery of the grain is solved. Now we need somebody to run friggin ColorFacts!!! :D


Later,

Jeff
 

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Coyote Waits
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Quote:
Originally posted by Iceblade
Weird how you never notice this stuff on a 36" picture from 10 feet away but notice it BIGTIME on a 61" picture from 12-13 feet away.
After returning a HLM507 to wait for the HLN567 I've been seeing all the stuff I never noticed on our 27" XBR. I'm also pointing it out to my wife as often as I can. You might call it my $4,000 propaganda campaign.


She really isn't picky about the picture as long as she can follow the story. It's me that needs a bigger screen to have that "carried away" movie experience.
 

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Discussion Starter · #8 ·
Yeah... it's really crazy what I thought was me seeing the pattern of the screen kind of "twinkling" (for lack of a better word) was actually some pixels turning on and off (while the picture was PAUSED even) and making it appear that the screen had texture across a fairly uniform colored part of the screen. For instance, the shot I chose to pause was in Attack Of The Clones as Obiwan and Anakin are riding the elevator up the side of the building before going to meet Padme. It's the close up of the two of them talking with Coruscant in the background. Lots of bright whites and stuff. Anyway... I was the twinkles or whatever and paused it. Basically it's part of the white background that is constantly toggling between white and light gray. Very freaky.


Anyway... I'm just glad it's not the screen.


Later,

Jeff
 

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Ice,


I believe what you're seeing, while perhaps partly due to MPEG compression, may also be due to what is called temporal dithering. To make each pixel display a particular hue and tint, the DLP chip oscillates that pixel's mirror on/off 1000s of times/second, sometimes through the red part of the color wheel, sometimes through the blue, sometimes through the green. The pixel is never "really" the one unique color you'd see if watching a film, it's a stuttering mix of RGB. If the stutter is quick enough, your eyes are fooled. But if its not, or if you look too closely, you see through the trick.


Doug


P. S. Sorry if I contributed to the hijack. Someone suggested upgrading your cables, which was relevant. Others denied that would matter and it spiraled OT. While I only responded to some posts I thought represented faulty thinking, the conversation by then was decidedly OT and so largely unnecessary. Mea culpa.
 

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Discussion Starter · #10 ·
Quote:
Originally posted by Doug Deacon
Ice,


I believe what you're seeing, while perhaps partly due to MPEG compression, may also be due to what is called temporal dithering. To make each pixel display a particular hue and tint, the DLP chip oscillates that pixel's mirror on/off 1000s of times/second, sometimes through the red part of the color wheel, sometimes through the blue, sometimes through the green. The pixel is never "really" the one unique color you'd see if watching a film, it's a stuttering mix of RGB. If the stutter is quick enough, your eyes are fooled. But if its not, or if you look too closely, you see through the trick.
Doug,


Ah HA! So THAT is what the temporal dithering is that I have seen pop up on the forums is. Yeah... it's somewhat distracting unless you are just totally engrossed in the movie. Like I think I mentioned before, I don't consider myself a videophile, but I think I know what "looks good" to my eyes, so it's a little bothersome that I see this issue. I am hoping that some SM tweaks get rid of this. If not, oh well... chalk it up to the hazards of being an early adopter.


Did anyone ever post info on the different types of "issues/problems" and perhaps some examples to view that could help with identifying this stuff? Things like the temporal dithering, color banding, etc... I just haven't see any.



FWIW, I DO see rainbows. But they are VERY few and far between and I really have to TRY to see them... so it surprises me if the temporal dithering issue is another one that you need to be "sensitive too" that I would see it without TRYING to.


Thanks,

Jeff
 

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I believe the DLP chip does both temporal dithering and good ol' (spatial) dithering. Here's a definition of spatial dithering:
Quote:
dithering

n : the process of representing intermediate colors by patterns of tiny colored dots that simulate the desired color
So for spatial dithering, a pattern of different colored dots would be used to simulate a color. Look closely at a color picture in a newspaper and you'll see this kind of dithering. The "twinkling" you're seeing could be the spatial dithering patterns changing from second to second, or it could be the temporal dithering of individual pixels described by Doug, or it could be a combination of the two.


These dithering techniques are "tricks" the DLP chip uses to display all the colors using a single DMD and color wheel. The idea is that you won't ever notice, but the fact is that you sometimes can, and even worse, under certain circumstances these "tricks" break down and you get nasty artifacts like color banding and pixel grain/noise.


If this really bothers you from a normal viewing distance, and you can't change UM and SM settings to reduce it, then you should probably either increase your viewing distance or buy a smaller DLP RPTV.
 

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Discussion Starter · #12 ·
Ah, thanks for explaining the difference between temporal and spatial dithering.


I just finished watching Episode Two again and I think I have my problem narrowed down to the two different kinds of dithering interacting with the "screen door effect" that is clearly visible to me from 14 feet away on bright scenes. Bummer. Oh well... I'm sure I am the only one who will ever notice this amongst my friends and family.


Something else... can someone check this for me. I was watching in a fairly well darkened room and I picked up a weird brightness issue. Go to Chapter 34. At around the 3:44 mark it has Anakin kneeling in front of his mother's grave. The sky is in the background. With my current setup, the overall picture brightness fluctuates on this scene from lighter to darker to lighter to darker until he stands up at like the3:50 mark or so. Anyone else notice this? I actually thought my eyes were just freaking out, so I went back to the scene and even saw the fluctuation in "reverse". Played it forward... still there. My guess is it is the DVD itself. Weird though.


Thanks,

Jeff
 
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