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hailtoby
Joined: 29 May 2008
Posts: 99
Location: Cook County, IL
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| Posted: Sun Jun 29, 2008 12:42 pm Post subject: NEC vertical stretch |
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Hopefully Im missing something easy here, heres the problem:
The PJ is an NEC 6PGXtra. It is being fed by a PS3 to a HDFury by a HDMI->DVI cable. After centering the rasters, focusing, and converging the picture looks pretty good, but the PJ is stretching the image vertically to fill the raster. Its acting exactly like a 4:3 TV. Ive tried setting the PS3 to 1080i and 720p and even 1080p and they all look the same...stretched.
I almost didnt notice it at first. I have a screen set up for my previous projector which had a shorter throw than the NEC, so I knew and expected the NEC to not fill up the screen. When I was doing the convergence the test patterns were not quite filling the screen width wise and were overflowing the screen top and bottom. I thought this would be fine, that when displaying 16:9, it would be in the center of the screen.
After the convergence was set, I played a trailer of of the PS3, thing were looking great. I was happy. The image was perfectly centered ont he screen and looked fantastic. The peoples faces looked alittle awkward, but I wasnt sure why. I was just happy to finally have the damn CRT hooked up.
I tried another trailer. This time the image overflowed the screen close to the same amount as a test pattern and had the same awkward stretched look. This trailer must be 16:9 and being stretched to 4:3 while the previous one must have been 2.35:1 or something similar and when it was stretched to 4:3 it was letterboxed just enough to fit the screen.
So hopefully somebody can make me say duh point me in the right direction here. I set up this PJ one other time, but I just did a quick job on the convergence and I cant remember if the image was stretched or not. I didnt use it too much due to the quick and dirty setup job. I just wanted to see it working.
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dbaisey
Joined: 09 Mar 2006
Posts: 821
Location: Southern Cal LA / Seattle WA
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| Posted: Sun Jun 29, 2008 1:25 pm Post subject: |
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The internal test patterns in the NEC projectors are 10% over scanned so you would want to use the actual source image to size it. If you have a 16:9 screen use a 1:78 format disc. Make sure the blanking is backed out on all four sides.
You may have something not set right in the PS3 also so that needs to be checked out. You may also be switching between 480P and what you have selected. Im not sure but I dont think 480P can be unselected.
If you have it set to use multi resolutions out you will need to enter each into memory and resize. If you are forcing one resolution the other formats will fall within the 1:78 and should be centered vertically if the linearity is set correct. Doug
Last edited by dbaisey on Sun Jun 29, 2008 1:55 pm; edited 2 times in total
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MikeEby
Joined: 24 Jun 2007
Posts: 5237
Location: Osceola, Indiana
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| Posted: Sun Jun 29, 2008 1:34 pm Post subject: |
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Welcome to the forum, what I do is set the horizontal size to fill the screen then use a test pattern with a circle and adjust the size (vertical) for a round circle. I use a tape measure, first measure the circle in the horizontal direction then adjust the vertical size control so the circle is the same size in the vertical direction.
Mike
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Doing HD since the last century!
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hailtoby
Joined: 29 May 2008
Posts: 99
Location: Cook County, IL
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| Posted: Sun Jun 29, 2008 2:39 pm Post subject: |
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Thanks, that totally makes sense now. I maximized the raster vertically and horizontally thinking that 16:9 would just be centered. Im used to digitals with a fixed resolution.
I will put up an external test pattern with the circle and adjust the vertical amplitude to get the right aspect ratio.
Thanks for your help.
EDIT:
That worked! Now I just have to tweak the corner focus and it will be perfect.
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