I have set-up what is almost - but not quite - a perfect HTPC. The problem I have is when playing DVDs and AVIs/MPEGs (DVDs are worse); when there are scenes that have panning or action I get some very strange artifacts. The worst of these was in a scene where the camera panned across a room and the picture had lots of horizontal black lines as the camera panned. Sometimes when a head moves quickly you get that strange effect rather like ghosting and when you get text scrolling up the screen at the end of a programme for the credits, it's a little jerky.

I am wondering whether it's my graphics card which is an nVidia 6200 based card. I have a Core Duo E4300 processor which should be plenty fast enough. I am going into the VGA connector of the plasma at 1024x768 (which works way better than 1280 x 1024 which the TV manual claims is the maximum resolution). The other thing I wonder is whether it would be better if I used the DVI out of the graphics card. Anyone know whether that would be the case?

Any thoughts anyone? I don't mind buying a better graphics card but it has to be AGP and it has to be fanless (those fans on graphics cards are so much more irritating than CPU fans!).

I should maybe say that the picture quality in stills or slow moving footage is superb!

Many thanks.

Well, I've plugged the PC into the plasma via the HMDI input using a little DVI to HDMI adapter and it makes no odds - the horrible artifacts and slight juddering on scrolling text is still manifesting itself.

I can't change the resolution to anything better than 800x600. Is that normal for DVI? I do have the proper nVidia drivers...

Hmmm, I've just tried playing the same DVD on my (Windows) laptop into the plasma. The fact that it plays way better than my HTPC makes me think it's not an issue with the card. (The laptop has a mobility Radeon 9600 card which seems to have around the same capability...)

Hi,

If I may interrupt your discussion with yourself , Could I ask what software you're using to play the DVD? Also, do you have the proprietary nvidia driver installed and configured correctly?

Sam

Your screen is not a plasma. It is an LCD. Plasma and LCD monitors are different. One uses a gas and other uses crystals. Plasma displays are the slowest and you will always see artifacts. LCD are the next slowest. If you want the fastest response times, a CRT monitor should be used.

The artifacts is caused by very, very high frame rates that is not matching the refresh rate of the monitor. If you set XVideo to vsync, it should be a lot better. Use the utility nvidia-settings to set it. If it still does not fix the problem, use mplayer and provide gl2 as the video output option with the vsync parameter.

Sam,

I've tried using mplayer and xine. I do have the nvidia drivers installed: you can see the nvidia logo on boot just before x starts. And thanks for interrupting the discussion with myself!

Electro,

I don't understand why you think I have an LCD and not a plasma. It's quite definitely a plasma! Thanks for the other bits of advice though, I'll have a play and see if I can find the nvidia-settings utility.

BTW, plasmas are faster than LCDs - one of the reasons I went for plasma over LCD...

Here's a quotation regarding the issue:

"When displaying moving images, “plasma is going to have fewer artifacts,” says Miller. “LCDs, even the best on the market today, will have some degree of trailing edge blur, because the response time of the liquid crystal is relatively slow.”

I am really not sure whether it's an issue of getting data from the graphics card to the TV fast enough or whether the graphics card can't render the graphics fast enough.

Using windows, you are using a different dvd drive, right? Is there any issue with the dvd drive you're using, for instance skipping, corrupting data, dirty lens?

You can also try changing the video output driver in either xine or mplayer like Electro says, it might fix the problem.

Only other thing I can think of is that you're not tuned optimally with your plasma screen, via the xorg.conf file.

Plasmas are slower. They have at best a response times of 30 ms. An LCD have a response times of 8 ms. In order to show a 30 FPS interlace content or 60 FPS non-interlace content. The response times have to be within 17 ms since both plasmas and LCD are digital or non-interlace displays. I do not who is Miller.

Yes, that's right, Windows is a totally different machine altogether. I did look at copying the DVD to my hard drive to test that theory but it wouldn't allow me to copy the larger VOBs which is odd. Also, I did wonder about whether DMA wasn't tuened on for the DVD, but I couldn't find an hdparm.conf file at all on my installation.

I have tried every single available video driver in mplayer - but must confess I've not played much with xine.

I'll play some more tomorrow when I have time.

I don't believe it's an issue of speed with the plasma though. On my HD TV Sky box the football, cricket, National Geographic is razor sharp - the TV itself is inherently more than fast enough to do this. A normal DVD player plays without any of these artifacts too.

Thanks for all the suggestions.

Plasma TVs are faster than LCDs.

Might want to check and make sure nvidia driver is installed correctly. I get strange artifacts and such with dvd's expecially on my lcd tv at high resolution but removed and re-installed the nvidia driver and it works perfectly now, but because i didn't really troubleshoot it not sure exactly what the problem was.

Only running a geforce 6800GS PCI-E on this system but even the 5200 FX AGP performs well on the lcd TV at max resolution although i have not tried the 5200 FX at a full 1920x1080, only 1440x900.

Edit: Don't think the LCD vs Plasma refresh differences matter in this case.

Viewsonic and Samsung have 2 ms LCDs out now. And I'm personally using a 4ms NEC 90GX2 at this very moment.

When I watch DVD movies with mplayer, there are no artifacts. I use the gl video output device and my video card is a nVidia GeForceFX 5700 Ultra (AGP version). I use OpenGL as the default video output device because it takes less processing power when I watch HD content and it is a lot smoother although my computer can only handle as high as 720p. The only time I get artifacts or tearing is when playing quicktime files at Apple Trailer site. The tearing annoys me just a little. The tearing appeared when I used tri-buffering. The tearing is caused by the desire refresh rate and the frames per second being a mismatch. To fix or minimize this, enable video overlays to sync to the refresh rate or the vsync. However, if the refresh rate is devisable by frames per second of the video content, tearing should not be noticable.

I still think LCD monitors are better than plasmas because the technology has been improved and they have the least amount handling problems. The blacklight is moving towards white LED. Sticky pixels is reduced or is not noticable because a special circuit to reduce the noise level.

I have gotten lucky with fixing those. Even on my 10 year old laptop still running with none and have none on any of the displays or tvs that i currently have. Have always been able to fix with a toothpick wrapped with a tissue, pressing on the stuck pixle and turning on the monitor or tv. So far they have always come back to life ( Currently knocking on the desk while i type this ).

Eh?!