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I've given some thought to my last posting:
http://www.avsforum.com/ubb/Forum10/HTML/009277.html


I'm currently thinking that the internal scaler of the projectors may be the problem? Please read the posting listed above before replying.


Ray


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[This message has been edited by Radar (edited 10-01-2001).]
 

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Ray,


I think you're right about the scaling. I just got an NEC LT154 (XGA), which likely uses a similar scaling engine. For a week or so, I was working off of an S-video input until my HTPC was built, and I could definitely see jaggies that I found very distracting. This was a big concern, but I decided to reserve judgement until the HTPC was set up.


I'm happy to report that with an HTPC driving the projector, the jaggies are pretty much gone. I suppose if I look hard I can see them (given the DVD is lower res than the screen), but the scaling engine appears to be extremely important for getting a good quality image out of a digital projector. I recommend re-testing with an HTPC input to see if your impressions change. I think you'll find a big difference.


Aaron
 

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I would agree with you. The progressive DVD player is outputting 480p video, and you are inputting via the component inputs. On both these projectors, the "Aspect Ratio" function has been implemented via the scaler circuit.


The only way to avoid scaling is to feed the HD15 connector with an RGBHV signal at 1024X768 resolution (a PC video board is the usual source) and select "Native" resolution in the projector menu. Using any of the other input options (component video, S-video, composite video) will always involve a triple processing (A/D conversion, digital scaling, D/A conversion) of the signal. Additionally, use of the S-video or composite video inputs (or even interlaced component video) will also invoke deinterlacing within the projector.


It's real simple - the LT150 and VT540 are business presentation projectors - they are therefore optimized for best display of PC signals. The video input options are "extra features" on these units, not the main application. You can realize an incredible video picture from an inexpensive projector, but only by bypassing the internal video processing and driving it at native resolution via a PC.


Gary
 
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