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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Wed Jan 14, 2009 4:33 am Post subject: Strange Image Problem (NEC XG-750) |
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My source is a home theatre PC 1280x720@72hz progressive.
I was finally able to photograph the problem.
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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Wed Jan 14, 2009 6:06 am Post subject: |
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Bad cables/cheap cables
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Tech support for nothing
CRT.
HD done right!
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Domminigan
Joined: 08 Oct 2008
Posts: 30
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| Posted: Wed Jan 14, 2009 6:09 am Post subject: |
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That looks an awful lot like Dr. Zoidberg to me.
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I need to paint one green and park them together.
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kschmit2
Joined: 09 Mar 2006
Posts: 1141
Location: Heidelberg, Germany
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| Posted: Wed Jan 14, 2009 9:15 am Post subject: |
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It looks like ringing.
Now we need to eliminate the source.
Software:
- Many animated DVDs/Blu-rays use excessive edge enhancement that will cause ringing. It's part of the signal on those discs and can only be mitigated using some highend videoprocessors.
- Display driver may have sharpening or edge enhancement turned up somewhere. This has virtually the same effect as edge enhancement, and can be easily fixed by setting those controls to the lowest value/disabling them completely
Hardware:
- there also are reflections inside poor quality cables or poor RGB drivers that can cause the same effect, particularly on VGA outputs.
A better cable may help, but only if the cause is not the line drivers. DVI out into something like an HD Fury would usually eliminate the problem.
For troubleshooting:
- try another DVD (if the picture was from a DVD)
- take a picture of a Word document or a website with fonts that are not too small. Basically something with black text on a white background. And some of the window should also be visible.
- check the display driver properties to find out if sharpening or edge enhancement are enabled somewhere.
- try another VGA cable
Kai
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Wed Jan 14, 2009 3:55 pm Post subject: |
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| kschmit2 wrote: | It looks like ringing.
Now we need to eliminate the source.
Software:
- Many animated DVDs/Blu-rays use excessive edge enhancement that will cause ringing. It's part of the signal on those discs and can only be mitigated using some highend videoprocessors.
- Display driver may have sharpening or edge enhancement turned up somewhere. This has virtually the same effect as edge enhancement, and can be easily fixed by setting those controls to the lowest value/disabling them completely
Hardware:
- there also are reflections inside poor quality cables or poor RGB drivers that can cause the same effect, particularly on VGA outputs.
A better cable may help, but only if the cause is not the line drivers. DVI out into something like an HD Fury would usually eliminate the problem.
For troubleshooting:
- try another DVD (if the picture was from a DVD)
- take a picture of a Word document or a website with fonts that are not too small. Basically something with black text on a white background. And some of the window should also be visible.
- check the display driver properties to find out if sharpening or edge enhancement are enabled somewhere.
- try another VGA cable
Kai |
It happens on all video, as well as desktop, not just with animated films.
My source is DVI out to DVI to VGA adapter to GammaX to Two 10 foot fairly thin vga extension cables to VGA to 5BNC cable.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Wed Jan 14, 2009 4:17 pm Post subject: |
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I'll bet it's the extension cables. Thin = cheap usually. Try running a short SVGA to 5 BNC cable and see if the problem goes away.
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kschmit2
Joined: 09 Mar 2006
Posts: 1141
Location: Heidelberg, Germany
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| Posted: Wed Jan 14, 2009 10:31 pm Post subject: |
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Is your source really DVI-D, or is it DVI-A through a simple DVI-I output and plug connector?
You have 2 10 ft extension cables after the gammax? If so, the final install should eliminate both of these cables and replace them with one higher quality cable that covers the full run (monoprice may be a place to look at).
For troubleshooting, as Curt said, use one short cable - probably move the source closer to the PJ to achieve that.
I would also try to remove the GammaX unit to make sure it's not causing the problems.
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Stonefool
Joined: 24 Dec 2006
Posts: 253
Location: Sweden
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| Posted: Thu Jan 15, 2009 12:50 am Post subject: |
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Huh, stupid as I can get, but I don't get it, is it the overall red tint or the "shadows" of certain lines that you think is your problem?
Otherwise adjust everything gain for the color, and adjust the video timings for the "shadows".
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Trying to get everything to work.
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Thu Jan 15, 2009 2:43 am Post subject: |
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| Stonefool wrote: | Huh, stupid as I can get, but I don't get it, is it the overall red tint or the "shadows" of certain lines that you think is your problem?
Otherwise adjust everything gain for the color, and adjust the video timings for the "shadows". |
The lines following the contour of every sharp edge, to the right.
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