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Discussion Starter #1
I don’t know the technical term but I don’t think it is tearing or banding


Where there is a vertical/up-down “sectional Pan†(as apposed to a full scene pan) I see the following in the “panned section†where there is motion such as a person jumping down to the ground:


-the illusion of missing horizontal lines for split second or two.


Its really strange and I have seen it on animated films like shrek and regular films like desperado superbit. I have seen it during midrange action close-ups as well as closeups.


I see it at 60hz and 72hz


I am using the LT150 with: ATI radeon AIW, ati player 7.1, P3 933mhz, sb live 5.1, win2k (all latest drivers, bios, sp, etc.)


Is it possible for someone to explain this?


thanks
 

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I am sure you have a good system but to be fair to the LT150 you need to use a very reliable source.


A progressive player would be a start or 480i normal player would work pretty well.


I used to get have all sorts of problems with the ATI player and maybe it is or isn't your problem.


I have played video games at 768p and 480p input. And I have used a lot of other types of displays would good success.


Likewise, hook-up your PC to a normal monitor to see if that display works flawlessly.


Also, try running your system at 60Hz if you were using 72Hz instead.


Good Luck,


Mr. Wigggles
 

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Hi loganross,


Something is happening! I never saw such effect on the LT150 in all my test and viewing using progressive, scaler and HD. I don't have a HTPC anymore.


BUT, last time I visited and saw CKL's LT150 with a GeForceMX HTPC in 1024x768 60hz. I saw the "illusion of missing horizontal lines for split second or two". Actually it least only around 0.5-1 secs in a wink of eyes.


CKL said WinDVD has more such effect than PowerDVD. Frankly, I've NO idea!


regards,


Li On
 

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Quote:
Originally posted by loganross


-the illusion of missing horizontal lines for split second or two.
Does it like horizontal scan lines appearing partially at some where of the scene? If yes, that's the problem of the encoding of software DVD player. I find WinDVD has the same problem that scanline artifacts appear several times in every movie. I didn't try ATI DVD player. This problem from PowerDVD is not serious. You can try the latest version (4.0XP). The video quality has been improved a lot (close to the WinDVD standard). Up to now, I didn't find scanlines from PowerDVD 4.0XP.
 

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Quote:
Originally posted by CKL
Does it like horizontal scan lines appearing partially at some where of the scene? If yes, that's the problem of the encoding of software DVD player. I find WinDVD has the same problem that scanline artifacts appear several times in every movie.
I don't think that tells the full story. I understand there maybe some DVD mastering problem (wrong progressive flag placement) which confuse software player and cause a split second of horizontal scan lines effect which is actually feathering/combing.


The scanline artifact I saw can come out from NOWHERE, even in static image such as a static DVD menu screen. Or happens around vertical movement object. And it happens RANDOMLY! Scan back and play the same scene and you may NOT see the artifact again! More study need to be done.


regards,


Li On
 

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Hi

I know exactly what you are seeing and talking about

Its like when the Super Hero Flash runs by , there is a

kind of streak.I thought this was what people were calling the

Matrix effect,but am now not sure it may be a whole new

phenomenom that only a few of us can see

This happens at 60Hz and 72Hz I use WinXP and Power DVD

and Win DVD.I noticed this effect quite alot on Final Fantasy,

Sherk, and TPM final Fantasy being the worst offender

Cheers Ray
 

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Discussion Starter #7
Thank you all for speedy replies. From your posts, it seems as if the issue is software (player or DVD). While that might make it a bit annoying I much prefer that they be at fault rather than the projector. Then again, i love the "home theater" so much that even if it were the projector I wouldn't care enough to change anything.



In the mean time I would like to see this thread keep going so that maybe together we can narrow down the issue and perhaps push for a solution. I will coninue to post updates.



One thing to reiterate: while the "missing lines" i see are horizontal I only encounter this issue when the motion in the scene is verticaland only in the portion of the scene containing the motion.
 

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Quote:
Originally posted by loganross


One thing to reiterate: while the "missing lines" i see are horizontal I only encounter this issue when the motion in the scene is verticaland only in the portion of the scene containing the motion.
MPEG2 artifact possibly. When the guys who made the mpeg spec in their wisdom included motion compensation they set aside a buffer of +-16 pixels for vertical pans - and +-1024 horizontal pans on the premise that horizontal pans happen more often and need to be prioritized. Whether that is the true reason for the missing scanlines during horizontal pans I'm not sure. I can see it on my standalone interlaced 626 in addition to my Skyworth, and the software players on my HTPC. I know a perfect source I can use to test even, Princess Mononoke during the opening sequence. I'll do a small test when I get home today to see if I can see it when ripping the video and looking at the actual source. It could for instance be a missing/black field.
 

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Discussion Starter #9
So does this mean that its simply a flaw of the DVD standard and no system can avoid the side effects
 

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Quote:
Originally posted by Frode
MPEG2 artifact possibly.
Not again! I suggest the DLP rainbow effect is also a MPEG2 artifact! You know, the projector manufacturers are laughing at us.


regards,


Li On
 

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I find that my lt150 exhibits very slight jerky pans when the action is in the horizontal pane. I too have an htpc with an ati aiw 1ghz chip and 256 megs ram.


Any comments.


ps.


Yes dma is enabled


warren
 

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Is the common thread, that this is only happening on the lt150?
 

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Discussion Starter #14
I don't know whether it happens to others. perhaps it even happens on standalone dvd players but is not noticable on a regular dvd.


We are currently waiting for frode to complete a few tests


thanks frode!
 

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At the first time I found this artifact at LT150+HTPC(Windvd 3.0), I did some tests. I found the same artifacts from an LCD monitor. So it was not the problem from LT150. After that I tried Windvd 2.x, PowerDVD 3.0 and Philips Q50 DVD player. Using the same scene to test it, I found that Windvd 2.x was the same as 3.0, PowerDVd 3.0 had less but still visible, Q50 has no artifact.
 
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