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I have an NRS processed dvd image feeding an updated input 5 of the Sharp 9000. Input 1 gets a Hi-Def (Time Warner NYC) direct feed . Both images are superb but...


When both images are 16 x 9, e.g. Shrek on dvd and any 1080i hi-def signal that Time Warner formats for 16 x 9, the images are different sizes. When input 5 fills the frame exactly, input 1 is small by I'd guess at least 4% to 6%. This was NOT the case when both feeds were using input 1. They were VERY close in size.


Does the mismatch result from the fact that input 5 has so little, or not any, overscan?


Thanks, Richard
 

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Correct - no overscan on Input 5 when bypassing internal scaler.
 

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I don't think I understand. Are you saying that the physical size of the image is smaller?


It seems that if the problem were overscan on input 1, you would have 90% of the image filling 100% of the screen, so you would see less of the image, but the portion of the image that you do see will be larger - sort of like zooming in on the image.


If the image is 6% narrower and 6% shorter, I believe what you are describing is not the result of overscan. It actually sounds like underscan.


But then I'm sort of new to all of this stuff.


Tim
 

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Quote:
It seems that if the problem were overscan on input 1, you would have 90% of the image filling 100% of the screen, so you would see less of the image, but the portion of the image that you do see will be larger - sort of like zooming in on the image.
Absolutely correct. The terminology is confusing for sure. More overscan means less of the video frame is visible, a "zoom" of sorts.


One fun experiment you can try on 1080i material is: increase the horizontal size on the projector to maximum, thus zooming in on the center of the image. If the image had more that 1280 pixels of horizontal detail, you now get to see that detail! If you don't see more detail, either it isn't in the 1080i material to begin with, or the projector is throwing away (filtering) the highest frequencies.
 
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