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Discussion Starter · #1 ·
I think the blacks in the DVD source aren't as black as my digital projector can project. Why?


Because the black bars on my 4:3 screen which are outside the 16:9/178:1 box are much darker than the additional black bars of either letterboxed or anamorphic DVDs (immediately below the larger top bar and above the larger bottom bar (which is size difference between 16:9/178:1 and the "shorter" 185:1 or 235:1).


I presume LCD pixels just don't "turn off" as some claim about CRT's, so the larger/exterior black bars should be a "no signal" situation. The blacks in the inside letterbox bars of the source, must be the black chosen by the makers fo the DVD. Maybe they didn't chose black black? I don't think so, because those blacks seem to match the black level of the source, which is almost always lighter than the "no signal" portion of my 38t LCD screen.


Have I drawn the right conclusion? What have I missed?


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Joe


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[This message has been edited by JHouse (edited 09-09-2001).]
 

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I have been meaning to write this exact question / problem for the past few days and I agree 100% !!!!! I think this is a very important topic.


We all talk about digital projectors not having the best possible blacks but I use AVIA to calibrate my brightness / contrast... I am using the scoped settings for my video card and output overlay, yet when I play a DVD the video image black is a long long way from what my PJ is capable of...


This is most noticable on the letterbox bars which are cropped by YxY (producing a true black) but begs the question that if the 'reference' black of the DVD is so far off how do I reclaim this for full CR that the display device is capable of...


Theres no point in saying how great it is to have real 'inky' CRT blacks if the source seems encoded at a level of black that is higher than the display device can do...


I have tried a few things to lower the black of the DVD image and by extension the video overlay of my HTPC but dont seem to get any closer....


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Joe, I think you're right! My DLP can in certain circumstances produce very good blacks, contrary to what many think, but it is source related. There is an interesting post from someone comparing the blacks on the new Sharp DLP with the Runco CRT and finding the Sharp's to be as good! Yet, Noah is complaining about the blacks on the Sharp. AlanG has stated many times that he thinks that some DLPs, for example, have blacks that are as good as, or nearly as good as good as, CRTs.


We need someone to compare a good LCD, DLP and CRT to each other - a how low (black level) can you go shootout. My CRT RPTV has grey bars and fails the black screen test at the end of Toy Story 2. The black border that surrounds my old WinDVD minimized screen when I made setting changes was a black as any black I have seen from any display device and this was with my DLP) and much blacker than what I see from most DVDs.


Try changing you brightness setting and I'll bet you can manipulate how "black" those grey "extra" bars will be.


It will interesting to see how the CRT FPs fair with the shadow test.


Cheers,


Grant
 

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Haven't tried numerous functions on my Toshiba SD-6200 DVD player, including one called "blacker than black." The manual simply says to turn this on when you adjust the black level of your TV with a test disc. Use a CRT set myself, but perhaps there's an approach here. See the "blacker" comments in this review . -- John




[This message has been edited by John Mason (edited 09-09-2001).]
 

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Well, being a CRT guy, I have noticed this as well. The blacks are still great but there is a difference in the masking bars generated by DScaler and the black of the material. There isn't much difference, so I just chalked it up to 7.5 IRE vs. 0 IRE being right next to each other. Are either of you using a 0 IRE DVD player?


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i am all over this point. i really think that dlp's are capable of more black than is on the dvd. i never brought it up because i don't have much experience with crt pj's and i wondered how they created such wonderful blacks. how can a pj with 800 ansi lumens output and 1200:1 contrast not make black (the marantz hd1 unit)?


greg


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i just read some of the other threads on this. i think it is a genuine question of how black does crt get? we all keep repeating the mantra but who has really verified this. i mean with a serious crt that has comparable light output to these new dlp's (i mean a g90). are crt's really black because they don't have much light output? are the really black compared to older dlp's? i would really love to see a g90 beside an hd1 dlp displaying the same black source. i wonder how big the difference really is now.


i have no doubt that a 7" crt with 200 lumens of output next to an older business dlp would be no comparison but i wonder what a really bright crt would do next to a new dlp. we need one of our members with a g90 to invite one of our new sharp owners over for a party. maybe alan and the gang will get the chance to try this soon.


greg


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I am not trying to argue against the ability of CRT to make deep blacks (they do, its just the nature of the system and also attaining good contrast is difficult for the transmissive and reflective technologies of digital projectors, its simply the nature of the beast) but this issue is definitely happening on my system...


I have tried tweaking and config but nothing can get the DVD image anywhere near to the absolute black that the machine is able to produce... It is painfully obvious where the DVD black of the letterbox bars are cropped by YxY's absolute black...


Does no one else see this ??


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Well, clearly a DVD can say "don't display anything here". Its just a matter of giving no luminance signal. Whether this or that DVD actually does it is another question.


Also most DVD players are going to put out 7.5 setup? If some later step in your video processing chain doesn't understand this, that would prevent it from generating complete blacks, right? Because it would interpret that as more than black.


If you've used the Avia/VE pluge to set up your projector for your DVD player, this should account for whether your DVD player uses setup or not, and should technically create no output at the appropriate places. But if your projector cannot hold black level under real world circumstances, those black bars will tend to be lighter than the black of the unused screen, because they are being 'infected'.


I guess we need to get Guy Kuo in on this one for a definitive answer.



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[This message has been edited by Dean Roddey (edited 09-09-2001).]
 

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As a former CRT owner who now owns an LCD projector I can say only .... the biggest single improvement to both was a shadow-boxed screen and variable black masking. If you can eliminate the halo of reflected light and the less-than-black letterbox bars, you've made the best "projector upgrade" you can make, and it's cheap.


Gary
 

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Quote:
We need someone to compare a good LCD, DLP and CRT to each other - a how low (black level) can you go shootout.
I hate to be a crashing bore on this subject http://www.avsforum.com/ubb/smile.gif but really there isn't anything to investigate. My CRT projector can do black. My LT150 can't. On a totally black scene, whether it's an artificially generated pattern, or a naturally occuring one on a DVD, such as a blackout between scenes, only the CRT does justice to it.


In my room when the scene is supposed to black on the CRT, you don't see anything. You don't see the room. You don't see the screen. You don't see anything.


With the LT150 the light coming from the halo alone is nearly enough to read by http://www.avsforum.com/ubb/frown.gif

 

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Discussion Starter · #14 ·
OK, that's it. I'm getting out my V/E and getting the black test up and seeing if I can see in my room. I'll let you know.


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Joe


"Well, it didn't look like a two-horse town, but try finding a decent hair jelly."
 

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Carefull,


It's discussions like this that have turned many a friendly audio enthusiast discussion into an audiophile war.


"Why can't we all just get along?"


-phil
 

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I'm pretty sure the difference is the whole "7.5 IRE" or "0 IRE". I believe all DVDs put out 7.5 IRE as their "black". The HTPC puts out 0 IRE as 'black', for the borders, or from yxy. Essentially, black to an HTPC is 0 IRE, but to a DVD it's 7.5 IRE. 0 IRE is "blacker than black" to a DVD. If your DVD player is setup for "0 IRE", I belive it maps 7.5 IRE to 0 IRE, and shifts everything down as well.


When I was playing with the gammas table on my Davis, it was quite clear that 7.5 ire was not black. I generated gamma curves that started at 7.5, in other words, 7.5 IRE put out *no* light. This made a big difference in making blacks look black.


I was told it's better to do this at the DVD player, instead of the projector, because of rounding error, but my projector goes 0 to 511 for each color, where I think the DVD only goes 0 to 255 per color.


But I don't know how to get WinDVD to do it, so it's a moot point!


Mike



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I know many who are using digital projectors have seen (and some own or have owned) CRT projectors. But I think it's becoming evident that many others have not actually seen a CRT projector perform in person. When it comes to black the difference between CRT and what you see with your digitals is not subtle. It's really just as simple as Jim has layed it out. I don't think looking at VE test patterns is going to give you a true idea of what this difference is, Joe. Try to find an opportunity to see this for yourself. I think you then will have an entirely different perspective. I'm not trying to proselytize that you should own a CRT projector. I'm trying to make the transition from CRT to digital. But I think you'll be the better for it once you have seen both.


Bob


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[This message has been edited by RobertWood (edited 09-09-2001).]
 

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With Vutec's black screen coming out, is this something that should be debated anymore? I'm holding off buying any screen until this thing comes out.
 

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My gosh I don't know how I missed seeing this before. Gary has said something in this thread which should be included in the Home Theater gospels and hymnals. All I can say is a big AMEN to this.

Quote:
As a former CRT owner who now owns an LCD projector I can say only .... the biggest single improvement to both was a shadow-boxed screen and variable black masking. If you can eliminate the halo of reflected light and the less-than-black letterbox bars, you've made the best "projector upgrade" you can make, and it's cheap.
Bob


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[This message has been edited by RobertWood (edited 09-09-2001).]
 
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