[mikef]

I am having an annoying problem where the picture seems very unstable during moderately fast horizontal pans.


HTPC: ASUS A7A266, Athlon 1.2GHz, 256MB PC2100 DDR, Matrox G400 16M AGP, Hercules Fortissimo II and ASUS 8x DVD-ROM.


Software: PowerDVD 3.0 (included with the sound card, I do not own anything else at this point)


Projector: Plus U2-1150 XGA DLP projector


Is this machine not fast enough for quality software DVD playback? The image quality is fantastic, however I cannot live with this instability in the picture.


Any assistance is greatly appreciated.

 

[Namlemez]

I would say that is judder. Not many people here still use a G400 and I'm not really familiar with tweaks for them. Your HTPC is fast enough, the "weakest links" seem to be the old DVD software and an old video card. Have you tried out some trials of a newer WinDVD or PowerDVD?

 

[mikef]

I will be getting a Radeon AIW 7500 soon, so hopefully that might fix the problem. In the meantime, I will take a look at upgrading my software player. Thanks.

 

[The Viking]

What refresh rate are you driving your projector?


I found that running my projector @60 would give me the best pans for my system. When I used 72Hz it introduced a lot of tearing (tearing: Happens when only a part of the picture is updated and not the full frame).


Also, the projector itself is providing motion smoothness/compensation, so pans actually looks pretty nice on my system @60Hz.


Thomas.

 

[mikef]

I tried 75Hz and 60Hz, but there was no difference between the two with respect to this "effect" I was seeing.

Quote:

(tearing: Happens when only a part of the picture is updated and not the full frame).

This sounds like what I was seeing. It was as if the top half of the screen was being refreshed slower/faster than the bottom half.


Admittedly, I am using an outdated video card and software. If that is the cause of the problem, I would be content knowing that my next upgrades will clean this problem up.

 

[Esben]

I'd suggest a newer graphics adaptor and another motherboard with a different chipset. The ALI chipset has never been good. Probably works, but far from optimal.

 

[mikef]

I was planning on a new video card anyway, so I will give that a try first. If that doesn't make a difference, I guess I will have to replace the board. I've never had any problems with it on any other apps/operating systems, so I am not quite sure how I can fault the board in this instance.

 

[coug7669]

Quote:

Originally posted by mikef I am having an annoying problem where the picture seems very unstable during moderately fast horizontal pans.

This is called temporal dithering and no amount of any HTPC tweaking will eliminate this "feature" . This is a Dlp "feature" that TI created to handle pans and motion artifacts. These two threads might be helpful: sharp 9000 and temporal dithering and technical white papers . I hava a Davis dlp that exhibited both tearing and dithering until Davis came with a software solution for the tearing. TI will have to come up with a fix for the dithering. It seems that the newer dmd's and light engines reduce this "feature".

 

[mikef]

Very interesting, especially the second link you provided, however, I still believe what I am seeing is caused by my HTPC. I would expect the effect you're describing to happen to the entire image, not cause the top and bottom halves of the screen to be slightly out of sync.