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Discussion Starter · #1 ·
LCD experts, help!


A friend is driving his Sanyo PLC-XP21N (packaged as a Proxima 9260+) projector, an XGA LCD unit, on its VGA/computer input with a HTPC equipped with an ATI Radeon AIW Pro video card. The DVD picture quality is suffering. It looks grainy and splotchy, especially with non moving parts of the image, for example, something like a wall in the background. Really colorful DVDs such as The Fifth Element look passable, but discs such as Fight Club don’t look very good. It almost looks like severe MPEG artifacting or a really misadjusted gamma setting – but fiddling with the gamma setting in the overlay controls for the player did not help. He has two players installed, Theater Tek and PowerDVD, and both produce poor picture quality.


His video card resolution is set to 1024 X 768, @ 60 Hz. Other settings, such as brightness, contrast, saturation, and hue, are at normal settings – maybe not optimal, but not misadjusted enough to cause the poor pq that I’m seeing.


My suspicion is that the projector’s internal scaling / processing is being engaged somehow. This unit’s manual makes confusing references about its component input being the only one that is progressive (?). In its menu selection, there is a segment called “PC Settings,†with fields labeled “horizontal lines,†“total dots,†“horizontal scale,†etc. Except for the resolution setting, which was set to 1024 X 768, the other entries in this menu area didn’t make much sense. For example, “horizontal lines†was set to 806 and “total dots†was set to around 1350. This makes no sense to me… shouldn’t horizontal lines be the same as the vertical resolution, 768? And “total dots,†which was described as “the number of dots in one horizontal pass†(or something like that)… shouldn’t that reflect the horizontal resolution, 1024? I tried setting these to 768 and 1024, but as I approached 1024 for “total dots,†a bunch of unstable lines would suddenly appear in the image.


I’ve seen excellent DVD pq from XGA LCD projectors that have inferior specs to this one. I know that artifacting can occur with the use of the internal processor, and that to get the best results, a digital projector must be driven at its native resolution with no use of its internal processor. How can I know that the internal processor is defeated?


Thanks,


Steve
 

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What version of the radeon drivers are you using
 

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Discussion Starter · #3 ·
Don't know - whatever came with the card. That withstanding, I think it is extremely unlikely that the poor video quality is due to video card drivers. In fact, I'm quite sure the HTPC is not at fault here. I'll have my friend simply hook up a montitor to verify that.


Thanks,


Steve
 

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I have a GeForce 2 MX in my PC (not using it with a projector, just watching DVDs on it occasionally) and basically, the picture looks like it's being rendered in 8-bit (256 colors) mode. Splotchy, grainy, soft, you name it, I've got it. While the resolution is higher than what I see on my TV, and the pictures is de-interlaced, colors look much, much, MUCH better on a standalone DVD player hooked up to a TV.


What am I doing wrong? I love the flexibility of PC DVD players, and want to use an HTPC when I get my projector (SX-21, ship already...), but not if this is going to be the pq I'm gonna get.
 

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You can get really muddy images with a digital machine if the phase and tracking are not set correctly....


Get this image and load it itled onto his desktop....

http://www.marky.com/files/hometheat...-and-phase.gif


Search out a post titled pixel perfection on DILA or similar by Mark Reijon from a couple of years back....


This could make scenes look muddy and exhibit constant noise....


Also make sure he is using a good SW DVD player... TT comes with the radeon settings already known and so makes it easy to get a good image and calibrate the HTPC (source) so then you simply calibrate the display to that... With multi source solutions it is real easy to have the source set one way and the display set the opposite to correct it and end up with clipping or being at the ends of extremes....


Keep fighting it... The 21N and HTPC combo was highly regarded !!!
 

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Discussion Starter · #6 ·
Phat Phreddy,


Thanks for the reference. Definitely something worth trying. But could pixel phase and tracking really account for the poor picture I'm seeing?


My experience has been that basic, untweaked default GeForce and Radeon HTPCs driving LCD projectors at their native resolution produce a significantly better picture than this. Any Sanyo XP21 users out there? What are your configs? Otherwise, I guess I'm relegated to searching the archives...


Thanks,


Steve
 

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I drive my Sanyo XP21 with an ATI 8500DV Equipped HTPC @native resolution on a greyhawk screen. I own a light controlled room with some ambient light due to glossy white back wall but it doesn't afect the PQ of this canon light PJ.


My PJ Settings:


36 Brighntess

28 Contrast

36 Red

28 Blue

32 Green


My FSync have been adjusted to show a perfect 1 pixel width checkboard.

The picture is nice. Way better then my panasonic Progressive DVD Player.


you need to make sure u download the latest ATI Driver because some rodeon cards have trouble with the gamma table with old drivers. the problem shows it self at low 30- IRE where you have crushed greys and at vey high IRE 70+. Search for cliff watson thread on this issue in the HTPC forum. he displayed a showed a nice faulty gamma curve.

I got my gamma settings set to 2.


I am very pleased with my PJ. I just finished a dedicated HT Room so I won't need those extra Lumens anymore. I am thinking about moving to a NEC 1000 once I sell the XP21N.
 

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I am running my HTPC to my Sanyo XP21 with awesome results.


P4 1.5Ghz

Asus P4S333 motherboard

Creative 9000 Pro 64Mb video card

Winfast 6X sound card

Power DVD 4.0 with upgrade patches


Good quality VGA cable to the projector.


Minimal Windows 98SE installed.


No additional software other than for playing DVD's.


Can send you Mark's Digital Test Image, to check if phase/sync is correct.

[email protected]


Cheers

Steve
 

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Discussion Starter · #10 ·
THE_COW_IS_OKAY,


Good info - two questions:


1. Where are you adjusting the gamma? In your software player's overlay controls? Or does the XP21 have a gamma adjustment? If the player has an adjustment, what are your gamma settings for both the pj and the player?


2. Where are you adjusting the Fsync? Powerstrip? I understand how to tile Mark Rejhon's test pattern over the windows desktop. Is that what you are using here?


I'll have my friend download and install the latest drivers. In fact, I'm thinking I'll have him blow away the machine a do a fresh install. He has a lot of extra stuff running on it.


HK-Steve,


Thanks for your menu settings - these are very useful. Have you ever messed with the menu settings under the "PC Settings" (I think that's what it's called)? I think it's right after the "Image" menu selection.


Thanks so much, guys…


Steve
 

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No I have not had the change anything in the "PC Adjust menu"


Though you can save a couple of different settings or modes so if you want to change the fsync or total dots, can be easily saved and changed.


I have now set and forget with most settings.


Fsync is in the image menu on the projector, you can adjust it two ways-

1- using the auto adjust in the "Auto Image Menu"

2- Using Mark's image adjust until it is pixel perfect. (this is how I did it and saved the setting)


I have just done a hard-drive Format and reloaded everything. I do recommend this, then you can cut back on what is on the HTPC. I have nothing on it that doesn't need to be. I also stripped back Win98 to a minimum install. Then installed the drivers without any extra programs.


No Acrobat reader, No Screen savers, No Anti Virus(as this is a stand alone PC, All software is Virus checked on my home PC first), No network/modem.


Hope this helps

Steve
 

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mr_ro_co,


Unfortunetly you can not adjust the gamma table of the PJ unless you go through the service menu. I don't advice so at all.


You can adjust the gamma settings of the your software DVD Player but I use many Software Decoders so I prefer changing The gamma value in the graphic card Video properties under overlay tab. Changes there apply to all my Decoders/Players.


I don't use powerstrip. Like Steve, I work out the sync settings in the PJ Menu.


More info can be found in HTPC Forum.
 
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