Sign in to follow this  
Sivar

Dell 2001FP image corruption

Recommended Posts

I just installed a Dell 2001FP. When I play movies larger than a certain size, the image becomes corrupt.

It looks interlaced, but "corrupt" interlaced rather than "formatted for conventional TVs" interlaced.

I can literally see increased image corruption as I enlarge the PowerDVD or MediaPlayerClassic windows, and decreased image corruption as I reduce window size.

Here are a few notes about the image corruption:

  • Only happens when the video screen is large. If a video is run in, say, a 720xNNN window, it's fine. If that window is increased in size to 2/3 of the screen, it is fine. However, when the video is maximized or made full-screen, the problem occurs.
  • Doesn't happen all the time, just most of the time.
  • Only happens when playing movies (either from DVD in PowerDVD or in a media player from a DivX media file). Does NOT happen when, say, playing a game or in normal OS use. None of these things show the slightest sign of any problem.
  • The offset lines of pixels form sort of a ghost of the original image. This ghost flickers, even when the movie is paused.
  • Corruption can happen in a window--the video picture is corrupt but everything outside of the window looks fine.

The image below looks sort of like a frame of animation between two interlaced frames, but that is not the case--it always looks like this. Interlaced video doesn't look different from progressive video if there is no motion, but this image corruption is present even in menus and legal notices (which have no motion).

2001fp_corrupt.jpg

Corrupt frame (zoomed in)

This is how the frame is supposed to look as taken from the DVD player's frame capture function. Note that the DVD player does not capture image corruption, so it must be happening outside of the player software:

2001fp_notcorrupt.jpg

What it's supposed to look like

What is the problem? Any ideas?

Share this post


Link to post
Share on other sites

(reducing) Hardware acceleration doesn't help. Drivers were all already updated.

This is clearly a software problem, but it is a mystery why it is a problem on this monitor and not the old one. Monitors just get a signal to display, whether it is analog or digital. Changing monitors really shouldn't change this sort of thing. Very strange.

Using MediaPlayerClassic, I changed the video render mode to one which requires DirectX 9. That seemed to correct the problem--for MPC, which I use to MPEG movies. MPC is not as good a DVD player as PowerDVD (though PowerDVD isn't that great either), and PowerDVD has no such option. (I'd try WinDVD, but even if the problem isn't present, WinDVD is such a patently horrible program that I'd rather have corrupt video than use it).

I am completely baffled as to how software video corruption occurs only on a specific monitor.

Share this post


Link to post
Share on other sites

Do you run this monitor @ a different res/color depth or from a different connector than the other?

Share this post


Link to post
Share on other sites
Do you run this monitor @ a different res/color depth or from a different connector than the other?

196293[/snapback]

I ran the old monitor at 1280x960. My video card's analog out is terrible, and I could barely read text larger than that. I could play videos at 1600x1200 (the new monitor's native resolution) though, and I tested video on the new monitor at 1280x960, 1024x768, and 800x600 and it still occurs.

(fixed permissions on the images in original post)

Share this post


Link to post
Share on other sites
Sivar I think you have a bad 6800 card. The analog isn't great but it's not as bad as you described it before.

196350[/snapback]

The DACs chosen are per-manufacturer. I imagine that Gainward chose a cheap-o DAC, figuring that most people with that card would also have a DVI monitor. In any case, the DAC is a non-issue other than for my server (which connects to the monitor with a VGA cable), and it has a Matrox card.

Share this post


Link to post
Share on other sites

If you can capture the corruption, then it cannot be with the DAC or the monitor. Would have to be something in software...

Sorry, I cannot tell you what or how. I wasn't there to log everything installed on the PC.

Share this post


Link to post
Share on other sites

This is definately a software problem. THe DVD is most likely encoded at 24fps with 3:2 pulldown. This means that the player adds the interlacing to bump up the framerate to 30fps. Also, scaling by an odd amount can really screw with interlacing.

I would play with the various deinterlacing options in both the player and video card settings.

Share this post


Link to post
Share on other sites

The distortion looks like a poor codec. I've had similar issues with installing DVD software and terrible codecs. However you've said before that you could barely read texts in some rez. That's not normal.

Share this post


Link to post
Share on other sites
If you can capture the corruption, then it cannot be with the DAC or the monitor. Would have to be something in software...

Sorry, I cannot tell you what or how. I wasn't there to log everything installed on the PC.

196403[/snapback]

The corrupt image was actually taken with a digital camera. The non-corrupt image was taken telling PowerDVD to get a screen cap. I actually took the screen cap when the image was corrupt, but PowerDVD captured an uncorrupt 720xNNN image, so its screen cap is somehow uneffected.

In this case there's no DAC involved since the new monitor is connected through DVI (now I can actually read text in 1600x1200!)

Share this post


Link to post
Share on other sites

Ah, didnt realize that. That's a nice pic.

Then if it doesnt appear in a cap it would look to me like a direct show filter or possibly a hardware issue (as you've already alluded to).

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this