Crushed blacks at 59 or 60hz, but not at 24 or 25? - AVS Forum
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post #1 of 16 Old 02-03-2012, 04:24 PM - Thread Starter
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Gear list:

Video card: EVGA GTX460
Connection method: DVI to HDMI cable
Display: http://www.elementelectronics.com/2011/12/elgft551/
Res: 1080P, with display scaling active to eliminate overscan

I was messing around, and noticing horrible black crush everywhere when running games or movies. I used this page to test: http://www.lagom.nl/lcd-test/black.php#blacktest.png

I cant see the 15 boxes at all. Not a one of them.

In experimenting with resolutions, I determined that if i turn the refresh rate down the 24 or 25hz, all the boxes suddenly show up. This would seem to indicate its a signal issue, not a panel issue. Of course, running at 24hz isnt really a viable option unless i was doing pure video, and im not.

But this one is stumping me, could it be my cable? Or some other setting im missing? Ive never seen black crush this bad.
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post #2 of 16 Old 02-03-2012, 04:36 PM - Thread Starter
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No crushed blacks at 50hz either. Only 59 or 60
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post #3 of 16 Old 02-03-2012, 05:22 PM
 
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Sounds like the PC is spitting out 0-255 video, and the display is displaying it as 16-235 video. Look for a 235-255 test that is similar to see if whites also crush.
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post #4 of 16 Old 02-03-2012, 05:50 PM - Thread Starter
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confirmed, everything from 244 (or less) up is gone in terms of whites

used this page to test http://www.lagom.nl/lcd-test/. Ok, excellent, now I know what it is at least. Next question is, how do I fix it (googling as we speak)

Also strange that it only occurs at 59 and 60hz, but not at 50 or below
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post #5 of 16 Old 02-03-2012, 06:05 PM - Thread Starter
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ugh, so apparently the standard fix was to create a custom res with nvidia, which would send the correct color space over HDMI. However, recently Nvidia disabled the ability to create custom res'es for common resolutions (such as 1080P), so while creating a custom res might work, it wont let you.

Theres tons of people with this problem
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post #6 of 16 Old 02-03-2012, 06:12 PM
 
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On the tv look for a Black Level setting. Normal is the default usually, Dark or Extended lets you render 0-16, usually.
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post #7 of 16 Old 02-03-2012, 06:20 PM - Thread Starter
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Quote:
Originally Posted by darklordjames View Post

On the tv look for a Black Level setting. Normal is the default usually, Dark or Extended lets you render 0-16, usually.

Thats a secondary problem I have actually. I cant get into the advanced settings menu on my tv. Its greyed out..
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post #8 of 16 Old 02-03-2012, 06:23 PM
 
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I would also investigate the P.Mode and Option>DLC settings on your display, as a black level settings seems to be missing entirely. If the TV is new, return the damn thing and get something that handles HDMI properly.
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post #9 of 16 Old 02-03-2012, 06:25 PM
 
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Advanced is only for VGA.
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post #10 of 16 Old 02-03-2012, 06:29 PM
 
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You could also try hooking up VGA, as a PC is likely the expected source there. I wouldn't be surprised if it rendered 0-255 by default over VGA.
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post #11 of 16 Old 02-03-2012, 06:34 PM - Thread Starter
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Quote:
Originally Posted by darklordjames View Post

I would also investigate the P.Mode and Option>DLC settings on your display, as a black level settings seems to be missing entirely. If the TV is new, return the damn thing and get something that handles HDMI properly.

im kind of amazed it took 10 post for someone to tell me element sucks. Sure, it is a super budget TV (with almost no settings or frills). But it was freaking 450 bucks for a 55 inch lcd. Im willing to deal with some hassle for that.
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post #12 of 16 Old 02-03-2012, 06:35 PM - Thread Starter
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Quote:
Originally Posted by darklordjames View Post

I would also investigate the P.Mode and Option>DLC settings on your display, as a black level settings seems to be missing entirely. If the TV is new, return the damn thing and get something that handles HDMI properly.

DLC, i turn off, and it turns right back on. I have suspected thats the issue too.

Right now im trying some modded nvidia drivers that supposdly force 0-255. We'll see if its true.
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post #13 of 16 Old 02-03-2012, 06:50 PM - Thread Starter
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Ok, partially resolved. The modded inf with the nvidia drivers now causes the drivers to transmit full color space in ycbcr444 mode, but not RGB still.

My curiosity makes me wonder whats up with RGB, but practically I wonder if i should just be happy and live with ycbcr444

any disadvantages to running ycbcr444?
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post #14 of 16 Old 02-03-2012, 07:01 PM - Thread Starter
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Posting for future reference for people with similar problems:

I have resolved it, for future reference, anyone hooking this display up to a HTPC with an nvidia card is going to run into an HDMI color space issue.

this display accepts 0-255 only, and nvidia cards by default over HDMI transmit 16-234. That means that you lose a good portion of your color spaces, and all the grey gradients from 1-16 just appear flat black, and all the grey variants from 234-255 just appear white. It really messes with constrast. I noticed it significantly when playing skyrim, it made it so dark it was hard to see.

So heres the fix: you need to modify your nvidia inf driver before you install, following these two guides (have to do both)

http://files.bortweb.com/how_to_fix_...en_or_text.htm
http://forums.nvidia.com/index.php?s...&#entry1005774

^^ post #5 in the second link.

Then switch your color space in the nvidia drivers to ycbcr444
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post #15 of 16 Old 02-03-2012, 07:28 PM
 
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Ycbcr will be just fine. If you get the full grayscale of 0-255 showing on your display, then you're good to go.
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post #16 of 16 Old 02-15-2012, 03:14 PM - Thread Starter
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ok, new issue in a bump to this thread.

A) Color space is messed again when i pass it through my HK avr247 reciever. This reciever is purely a bypass mode passthrough in 1080P, so it really shouldnt be touching the signal at all, so im guessing its an nvidia sensing issue again
B) The mini-HDMI to HDMI output of my 460 has crushed blacks even with the hacked driver and Ycbcr. DVI outputs properly though (but not when passed through the AVR)

I have a "working" solution, in bypassing the receiver and running straight DVI > HDMI > TV, but its not a streamlined one. Ideas?
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