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Discussion Starter #1
Hey folks,


I just built a new htpc and when I play a movie, the display goes blank and comes back too bright (about 20 clicks on the brightness control on the tv).This happens with 2 different programs (latest build xmbc and J.River Media Center 17 with MadVR).


The hardware:

Asus p8z77-m with i5 3570k/hd4000, 8gb ddr3-1600 running Windows 7 64-bit, all latest drivers from the respective vendors (not from Asus as they don't update very fast).


hdmi goes to a Denon AVR-4306, hdmi out to LG 50PK250.


I went through all the settings to make sure its all set to RGB 16-235, I've reset the TV to defaults and redid its initial wizard and I ran Windows calibration (didn't change anything except gamma slightly down, certainly not the 20 notches described above, not even close
).


The desktop looks good but when I start a movie, mkv 1080p x.264, the display goes blank and after a short second comes back too bright, it looks really washed out. I need to drop brightness about 20 notches on the TV controls to compensate. Then when I look at the Intel COntrol Panel, I notice Quantization range is back to default. When I change that back to limited and leave the window open, I will get a dialog box stating 'please wait while settings are being applied'. When that's done, its back to default again.


I'm not sure if that setting is responsible for the washed image as I don't see a change when I manually set it back, but obviously I don't want it to do that. I've disabled 'movie detection' in the control panel too as I figured that was detecting playback and forcing settings, but that didn't make a difference.


Also note that the movie doesn't have to play full screen. In MC17 I can play it in a window and I actually see the entire display is too bright, not just the movie window.


I'm not sure what to try next though, I just want video to play back 'as is', I never had this problem with my old htpc (ASRock ION 3D, Atom 525D with Nvidia stuff).


Any help would be appreciated,


Thanks!
 

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Discussion Starter #2
I figured it out, the setting had to do with the Denon set to RGB normal, the brightness went back to normal levels when set it to YCbCr and enabling that setting on the driver too.


What I don't get though is that in MadVR I have to set it to 0-255 on the display controls, on 16-235 is still too bright (not as much though).
 

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Appearently I keep answering my own questions here.


From another thread I downloaded AVSHD pattern manual and downloaded a couple of mp4's to calibrate the tv. My tv has a color filter built in so that worked quite well.


A few settings confuse me and I did end up with some 'issues'.


The TV is an LG 50PK250. It has the following settings:

Gamma: low, medium, high. Low = brighter, high is darker.

Black level: low, high. Low = brighter, high is darker.


Obviously there are all the 'normal' settings like brightness, contrast, edge enhance and H/V sharpness.


Half of the time I spent on calibrating was trying combinations of gamma and black levels, compensating by lowering/raising the brightness.


It seems like I can get good black levels with 17 being a nicely visible shade of dark grey. In this setting however whitelevels are visible all the way up to 248 and 235 isn't bright white. In this setting gamma and black levels are set to low, and brightness is brought down to compensate. Contrast is set to 90.


When I get 235 bright white with no other tones visible, I can't get black properly fading. 17 becomes a few scattered shimmering pixels, 18 a few more but only after 20 do they become a nice shade of grey. In this setting gamma is on medium and black levels high. Contrast clips and needs to go down to 75-80, brightness needs to go up to ~55.


What I'd like to hear from people with experience in this field (hopefully even with this TV model) is.

- should MadVR be set to 0-255 or 16-235?

- which combination of gamma and black level should I be using? As far as I'm concerned gamma is not the same as brightness and neither is black level. What is better to use, low gamma/low brightness, or high gamma/high brightness? What about low/high black levels?


When I was done calibrating, MC played perfectly, good quality although I must say that relatively lower quality video files are more obvious than before. XBMC however was way too dark. Ideally I would like both to play the same files similarly. Granted MadVR is higher quality renderer but that shouldn't matter for brightness.


Any help would be appreciated,


Thanks.
 

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0-255


Do you have a link to the AVSHD pattern manual?
 

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Have you tried putting everything to its default setting, and then using just your display's brightness (for getting 17 adjusted to just above black) and contrast (for getting 234 to just below white) settings for adjustment? How close can you get to ideal using that method, with the AVC contrast patterns (with the flashing black and white bars)?
 

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Discussion Starter #7

Quote:
Originally Posted by jim2100  /t/1418578/brightness-issue-with-hd4000#post_22192436


Have you tried putting everything to its default setting, and then using just your display's brightness (for getting 17 adjusted to just above black) and contrast (for getting 234 to just below white) settings for adjustment? How close can you get to ideal using that method, with the AVC contrast patterns (with the flashing black and white bars)?

Oke. I reset the tv to factory defaults again. I initially changed horizontal and vertical sharpness to 0 and change temperature to medium (default is warm which is waay to orange). I checked if temperature would affect clipping and it doesn't.


I went through all the settings to verify all is set oke (described in OP).


I did find the reason why the desktop was too dark and why xbmc was too dark too, Windows calibration profile. I reset it to the default sRGB profile. MadVR seems unaffected by this setting, unlike xbmc.


Using 0-255 in MadVR I found everything was so dark I had to increase brightness to 62, serious clipping, only saw 3 bars of white and the background turns light grey with blacks becoming visible at 23. I took gamma and black level to low on the TV settings and decreased brightnes to 51. This is the best I can get it so far:


Black is visible from 19 onwards (18 has a few pixels shimmering but thats invisible from 1 meter distance) and white is visible up to 232. So 17 and 18 fade in the background and 233 and 234 clip.


I haven't done the color calibration yet.


Preferably, I'd have blacks up to 18 with only 17 dissapearing in the background and have a few more tints of white (lets say up to 240) but I have no idea what I can expect from this HD4000 and how to accomplish that?


Thanks.
 
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