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Discussion Starter · #1 ·
When it's on my projector?? Anyway, I'm trying to adjust a Dukane 9000 projecting at a Stewart 96" x 54" 16:9 screen. This is connected to a Radeon based HTPC.


Anyway, I'm starting with the basics: trying to get my computer desktop image to fit the screen. I've followed the instructions in DILARD to load the "16-9 Computer Material on 16-9 Screen (Perfect Timing)" mod to the Dukane 9000, and PowerStrip 1360x768p (DILA) custom resolution.


This gets me pretty close, but the projected image doesn't quite seem 16:9! In fact, the projected image can be zoomed to about 54" by 92" leaving two inches unprojected area on either side of the 96" wide screen.


I understand that 1360x768 is not exactly 16:9, but I shouldn't have a four inch difference, right?


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- Dan Butterfield


[This message has been edited by danjb (edited 08-26-2001).]
 

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Hi Dan,


Try fiddling the "Top" parameter in the Image Geometry Wizard (and/or the Vertical Position end user control) or possibly the "Top" setting in PowerStrip.


You might have a few inches of source material being cut off.


Are the bottom of your taskbar and the top of a maximized window both visible?

 

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Discussion Starter · #3 ·
I did verify that the whole screen is being displayed and not being cut off. In fact, I did a screen capture to make sure I was seeing every pixel in the 1360x768 image. I checked the corners of the projected image to make sure every pixel from the 1360x768 screen capture were visible. I actually took a tape measure to the Stewart screen to make sure it is 96x54 (it is).


I understand there is some inevitable error when the digital world meets the analog world, and some amount of fudging might have to occur. Do other folks get exactly a 16:9 projected image when projecting a 16:9 ratio resolution?


Is it possible there is some unique adjustment I have messed up in either my HTPC or projector when the DILARD mod and PowerStrip custom resolutions are loaded?


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- Dan Butterfield
 

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Dan,


I sent you my 16:9 mod. Let us know how it works.


Chris
 

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Discussion Starter · #5 ·
Thanks for the mod, Chris! I'll try it tonight. When it first showed up, I didn't immediately recognize your mail id vs. your AvsForum id, and thought perhaps someone was sending me a bogus mod to blow up my projector... http://www.avsforum.com/ubb/wink.gif


One thing that might be related to my problem: my ceiling mounted projector is actually maybe 10 inches above the top of my screen, and is at about 210 inches from the screen (this is too long of a throw distance for me to shrink the whole 4:3 image to 54 inches high, but of course I can widen the image to 96 inches wide with no problem).


Could the offset from my projector height to the top of the screen account for the aspect ratio difference I'm seeing, as a result of keystoning? There is indeed keystoning; the four inch difference I mentioned in the original post is measured at the point where the image width is the widest (the bottom), so is actually worse higher up where the image is thinner.


On a related note: I have a Panamorph on order. Will it:
  • Make this situation worse; even more keystoning
  • Make this situation better (less keystoning)
  • Do nothing for this situation (same keystoning)[/list=a]

    From reading other posts on this forum, I got the impression the answer was (B) but maybe that was wishful thinking...


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    - Dan Butterfield
 

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Sorry about that Dan. My wifes name is Cyndi, so our e-mail is "cyndaroo", a knickname. Kinda like kangaroo, except she doesn't quite hop to when I say do. http://www.avsforum.com/ubb/biggrin.gif



Good news and bad news.


The good news is that the addition of the Pannie will drop your image. The bad news is that the top of your image will now be 7" below your top of screen. You will probably have to first align the 752 to be perfectly level with the Pj, then tilt the whole assembly up a few degrees to reach the top of your screen. That's not so bad, though.


1. With a 210" distance, your tilt will be only a few degrees.

2. The Pannie introduces a fair amount of barrel distortion that improves somewhat if you tilt up or down, i.e., tilting the image up will make the upper portion straighter on the edges.


It may not be geometrically perfect if you throw up some of the test patterns in VE or AVIA, but in most DVD viewing you'll never notice it. Besides, if you can't move the position of your projector or screen, you don't have a choice, right? http://www.avsforum.com/ubb/smile.gif


How much tilt do you have now?


Chris

 

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Discussion Starter · #7 ·
Chris, you're a genius! Your mod gave me up/down motion with no truncation (a problem I mentioned in another post), and got me closer to a 16:9 projection!! Thanks. For some reason, though, when I run with the PowerStrip "DILA 1360x768 pixel perfect timings" I lose some pixels from the right side of my screen (basically, about the width of the close X icon).


I went into PowerStrip, and had to change some of the "Advanced timing" settings. I had to change the Horozontal settings for Total, Front Porch, and Back Porch (to 1808, 129, and 239 respectively). I now have exactly a 16:9 1360x768 display (about 2-3 inches of keystoning at the top, but an exact fit at the bottom).


My only question remaining (on image geometry at least) is why does this seem to be "black magic"? I can understand how different projectors have different color responses, but it would seem like image geometry would be identical between same model projectors. I would think loading the Dilard 1360x768 16:9 mod and the PowerStrip DILA 1360x768 perfect timings would result in an exact 16:9 centered image on any DILA. Why doesn't it?


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- Dan Butterfield
 

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Hi Dan,


There are also some end-user positioning controls as well, which shift the source material within the pixel array. PowerStrip does the same thing, but from the other side.


There sure are a lot of variables! It sounds like you are closing in on it.
 

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Thanks for the compliment Dan, but the credit really goes to Mark Hunter for his excellent work in providing us with the Dilard software for our DILAs. http://www.avsforum.com/ubb/smile.gif


Personally, with the Dilard mod and the Powerstrip DILA 1360 x 768 setting loaded, I prefer to do final position tweaks using the "position" controls first, the Dilard Geometry Wizard second and the settings in the "Advanced timing options" as a last resort.


You should definitely be able to get to a point where your entire desktop is in the perfect 16:9 ratio image.


Of course this will all change when you get your Panamorph lens. http://www.avsforum.com/ubb/smile.gif You'll be going back to a 1360 x 1024 setting.


Chris
 

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Discussion Starter · #10 ·

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Dan,


It'll be worth the wait, pal.


You'll not want to go back to the non Pannied scenario ever again. And, it works really great for 2.35 movies as well, an extra bonus. I thought I was going to have issues with 2.35 stuff, but they came through perfectly on the screen, holding their 2.35 ratio. The neat thing for me was that I could zoom out to get even a larger image with 2.35 discs than with 16:9 discs because of the fact that my current 96" screen is larger than my 16:9 image, so when 2.35 discs are on, I have room height wise to zoom out and fill more of my screen. Makes 2.35 DVDs look really, really good. http://www.avsforum.com/ubb/smile.gif


Chris
 
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