AVS Forum banner
Status
Not open for further replies.
1 - 12 of 12 Posts

·
Registered
Joined
·
153 Posts
Discussion Starter · #1 ·
Today I went to see a D-ILA projector for the first time, a Panasonic PT-L995U. I brought my DVDO I-scan and a Sopranos disk which I have used with the I-scan before. I used the RGBVH connection into Computer 2. We let it scale the disc to 960 x 1280, which isn't correct but guaranteed the simplest scaling from a DVD. However, we had a lot of problems with video noise. In the walls in the backgrounds in Dr. Melfi's office, it looked like a swimming, grainy pattern. I also saw some problems with edges and lines which in the past I assumed were scaling artifacts. The last Sony 10HT I saw looked a lot better even though it had the more difficult task of scaling a DVD to 720P. I know we did something wrong. Is there a better combination of input and format I could have used that would have improved the image?
 

·
Registered
Joined
·
4,106 Posts
Did you turn "Resize" off on the D-ILA for that input ? The I-SCAN is a notoriously bad match for the D-ILA, but if you let the D-ILA re-size the image it would be even worse.


The D-ILA projectors need to be paired with a device that can scale to match the native resolution exactly. That means an HTPC, Vigatec, Rock, -- or Crystal Image, or Quadscan Pro on the lower end.


------------------

*********************

Kirk Ellis

G1000 D-ILA, HTPC, Panamorph (soon I hope),

Dish 6000 (HBOHD,SHOHD,CBS,NBC,ABC,WB,FOX,UPN, KCET -- does it get any better ?)
 

·
Registered
Joined
·
1,286 Posts
Aha!


I am the proud new owner of a D-ILA G20, and I see this exact thing. I'm actually sending it back to JVC for service on an unrelated issue, and am now using a G11 they were nice enough to loan me. Same problem on the G11, too. I'm also connected to RGBHV on Computer 2. Hmmmm. I'm using a Geforce based HTPC with perfect timings, and all that, so it isn't a scaling issue either.


Love to hear if anyone knows what causes this! Could it be the RGBHV connection on the projector?


- Dave
 

·
Registered
Joined
·
1,735 Posts
Richard,

Kirk's statement is accurate when referring to scaler artifacts, but I am puzzled by your statement regarding "we let it scale to 960*1280". The D-ILA when set to autosynch on comp2 will take your 480p (output signal of the DVDO) signal and scale it up to 1365*1024. This assumes that the resize switch is on. If the resize switch was off, you would get an extremely small picture because you would only be using a small portion of the panel. The least desirable signal input for the D-ILA is 480i, because the projector does not perform the inverse telecine function when converting from interlaced to progressive video. With your DVDO there should not be video noise, but there will be scaler artifacts. May I assume you fed the DVDO a component signal with a set of cable that maintain 75 ohm impedance throughout?


Since I am unsure if the Sopranos is filmed or videotaped, I am not certain that it represents the best source material for evaluation of a projector. If Starship troopers, The Fifth Element, or Toy Story 2 demonstrate this problem, then something is not setup/calibrated correctly.


It also seem like the projector is not correctly calibrated. The swimming pattern on the wall, sounds like posterization to me.


Dave T,

as you probably know, the scaler is on all the time. Without the scaler, you would not see a picture. All we can do is feed the projector an image as close to panel resolution as possible, to minimize the work the scaler has to perform. The only acception I have noted is with 1080i HDTV material, where the D-ILA's scaler simply performs magic (IMHO). Being that this is your second projector that performed identically with same source, I would suggest that the most likely sources you problem the breakout cable, video card, or potentially RFI/EMI noise being induced in your system. Try a different cable first, but I think the most likely culprit is your video card. Have you ever connected a different source device to your D-ILA? Even a progressive scan player should not produce disastrous video noise. Just to be clear, are you experiencing this problem with both video and film based source material?


------------------

STOP HDCP on DVI

Don O




[This message has been edited by Don O'Brien (edited 06-06-2001).]
 

·
Registered
Joined
·
1,286 Posts
Don:


What I meant was that I'm sending the projector its native resolution (actually, ... no - I'm sending it 1365x768), so the scaler shouldn't have anything to do. The resize option is disabled, which would confirm this...


I concur that the potential sources of the problem (other than the projector itself) would be the cabling, the PC, or some kind of noise. I need to do as you suggest, and try other sources, but I'm not hopeful. My cable was custom built by someone who knows what they're doing, and was absurdly expensive; and my PC is a pretty generic GEForceII based HTPC (from AVS). I've also got everything connected into a power conditioner.


Richard's post just got me thinking that it might have something to do with connecting a PC to the RGBHV input on the projector. I don't think that's too common, is it? Anyone doing this and not seeing this "noise" problem?


- Dave
 

·
Registered
Joined
·
2,165 Posts
Richard and Dave,


This description of a "swimming grainy pattern" in the background almost sounds like what I saw the first time I ran my Black Level Wizard in Dilard. Posterizing, as Don mentioned. It was easily fixable though by backing off a little on the RGB percentages in the wizard. Prior to that, I've never seen anything like that on my stock G11 no matter what I threw at it. Artifacts yes, bad transfers yes, the ocassional blue grain in a very black scene. Even with tweaking the user settings to their maximum, I never saw what you're both describing. Are these projectors bone stock?


I used the Comp 2 input for months before switching over to Comp 1 for my HTPC. I doubt very much that would be the problem.


480I is pretty bad on the DILA. 480P isn't much better. A 640 x 480 desktop is the *only* time I've been able to use Resize and noticed an improvement in the image without screwing up the size of the image, FWIW.


Richard, will you be able to view the projector again using a better DVD?


Chris
 

·
Registered
Joined
·
1,286 Posts
Chris:


I'm not sure if it's the same thing Richard saw, but what I'm talking about is not just visible in dark colors. Walls, sky, etc are all suceptable. So, would that eliminate black level related causes?


I've seen this from all DVD's viewed so far, from my HTPC. I see it both on my calibrated G20 (calibrated by JVC Digital), and on the G11 loaner, which I would assume has not been calibrated.


- Dave
 

·
Registered
Joined
·
2,165 Posts
Dave,


The noise I was seeing was actually more evident on lighter color shades, like skies and whites, so it may indeed be like what you are seeing.


I stand to be corrected on this perhaps, but I think the lowering of black level thru the Dilard program was giving me the posterizing due to the fact that the gamma curves were changed along with the black levels. As we don't have yet the final(?) Gamma Wizard to acheive gamma correction, the Black Level Wizard took the gamma down to a point where this posterizing was visible. This will soon change though. I think Mark is rounding third heading for home.


If what you're seeing is really what I was seeing, then it could be black level related. Since I bumped back up the black levels on my G11, the posterizing is gone *and* my black level is better. The problem is we don't for sure what you're seeing. http://www.avsforum.com/ubb/smile.gif


Wasn't there some discussion about posterizing or banding on the JVC calibrated DILAs awhile back?


The fact that you also see it on the loaner throws a guy into thinking the problem could be non-DILA related though. Anyway to find out if the loaner is cal'd?


Chris
 

·
Registered
Joined
·
1,286 Posts
Chris:


I don't think adjusting the black level would cause posterization on lighter colors, but I could be wrong.


The thread about posterization on the JVC calibrated projectors was one I started. There's still no proof that that's what I was seeing, and now I'm less sure, because I tend to doubt that the loaner would have had JVC's calibration done to it. The calibration is intented for projectors to be used for video, and I wouldn't think they'd do it to a generic loaner, which most likely wouldn't be used for video.


- Dave
 

·
Registered
Joined
·
153 Posts
Discussion Starter · #10 ·
I have used this DVDO with a Sony CRT projector in the past using the exact same RGBHV cable, and with two different computer monitors using a 15-pin cable, and it didn't have any of these problems. I didn't use The Sopranos because it would make the D-ILA look the best, I used it because it's dark and incredibly detailed. And on my 31" Gateway monitor with the DVDO it is the best-looking DVD I own, deeply 3-dimensional and detailed. I am terribly disappointed by what I saw yesterday. If the only solution is to use a computer, then I'm just not going to buy a D-ILA.

As for the use of the resize button, we couldn't find the resize button. We went thru the Computer 2 menus and I went thru the manual and I couldn't find anything to change anything about the scaling. But we did see a gray band all around the screen that seemed to indicate not all the pixels were being used. We didn't have a good DVD player on hand, just a Panasonic professional unit. But I can't do anything about that. I have 48 hours to decide on buying this projector, it may be the only chance I'm ever going to get in Houston to see one before I buy it, and it's far too expensive for me to make a mistake. I might get a 2nd chance to look at it, but that's it. I have to know exactly what to do on the 2nd trip to fix the projector or I will have to give up. It just doesn't make sense to me that the D-ILA looks so much worse with a 480-line DVD than a Sony 10HT after all the praise I've heard for the former.
 

·
Registered
Joined
·
2,165 Posts
Dave,


Maybe "posterization" isn't the correct term for what I was seeing, but it sure sounds like what you two are describing. Excited pixels would be more of a precise term, most evident on lighter image areas. It *was* caused by adjusting the black level thru the Wizard. Maybe it should be called gamma noise. I make no claim to be an expert on calibration or terms. http://www.avsforum.com/ubb/smile.gif


Keep in mind this isn't the user controls, it's the Dilard Black Level Wizard. Sounds like I'm knocking Dilard. I'm not. Only giving info as to how I came about seeing the noise like you're describing.


Richard, will you be viewing the Pj again? Try taking the DVDO out of the loop. What does the owner/vendor say? I'm not familiar with the Panasonic. How does it relate to a JVC? I've had two JVC DILAs and even with the cheapest DVD player I owned, I never saw the "swimming", but I'm starting to think that you might just be seeing some ill effects of using the res you were using. Did you try any other resolution?


Quote:

"As for the use of the resize button..."


Unless you're in 480, don't bother with it.


"But we did see a gray band all around the screen that seemed to indicate not all the pixels were being used."


That's should be the infamous DILA halo. Quite normal but maskable. http://www.avsforum.com/ubb/smile.gif


"If the only solution is to use a computer, then I'm just not going to buy a D-ILA."


I agree with you there. If you're only going to use a DVD player and the DVDO, save your bucks and buy a cheaper projector. The DILA(JVC anyway)shines it's best with HD and 1360 x 1024 resolutions. With anything less, the Sony may indeed look better.


Chris
 

·
Registered
Joined
·
1,735 Posts
Richard,

it seems as if you have some time pressure. Is there anyway you can get someone to lend you a DVD player with progressive component out? If not, then feed the YPbPr signal to the D-ILA on the component video input and see if it improves the image. The 995 is the same unit as the G1000 which I own. I owned a first generation DVDO and never saw the severe problems you are describing, so something is up.


------------------

STOP HDCP on DVI

Don O
 
1 - 12 of 12 Posts
Status
Not open for further replies.
Top