Black Level Calibration

RobMcM

Active Member
Warning: long post ahead. Hopefully it’s in the right forum, and describes properly what I am struggling with. Also I know that the equipment I am using is not exactly new, but this is really frustrating me so I’m turning to you all for some advice.

My setup is an Oppo BDP-83 passing through via HDMI to a Denon X2100 AVR into a Samsung F6670 TV. I also have a Windows HTPC running Kodi which feeds HDMI into the same AVR then on to the TV, also set to video pass through.

I am trying to set the black levels properly on the TV so they are consistently correct across both sources. I’m using the AVS Calibration Disc from here to do so. The problem I have is that when I set the levels from one source, they seem incorrect when I switch to another.

Here’s what I did:

On the HTPC
  1. Following the advice from here, I have Kodi set to output Limited RGB range, Windows display drivers set to Full, TV set to “Low” (which I understand to be Samsung-speak for “limited”)
  2. Using the AVCHD iso copy of the AVS calibration disc in Kodi, I set the brightness and contrast levels on the TV so that the black levels 17 and above flash and the white levels are flashing as they should. The greyscale ramps look good and gives me a pleasing image in movies which looks good to me.
Then I switch to the Oppo, and pop in a physical disc burned from the same iso I used in Kodi. Now, no matter what I set the “color space” in the Oppo settings to be (auto, RGB PC level, RGB video level, YCbCr 4:4:4 or YCbCr 4:2:2), the black level patterns show the screen is far too dark. I don’t get any flashing bars at all. The only ways I can find to fix this so levels 17 and above flash as they should are either:
  1. Raise the brightness of the tv by about 10 points. This makes the oppo output look right but obviously makes Kodi too washed out.
  2. Raise the brightness of the video within the Oppo menus by 5/6 notches. This corrects the darkness, but I’ve read that these shouldn’t really be adjusted at all and all adjustments should be made on the display.
How can I resolve this? I suspect I should calibrate the display to the Oppo output then fiddle with the various settings in Kodi/Windows to find a way to “fix” Kodi to match, but this will probably mean using something other than limited/full/limited which apparently will make the video levels Kodi outputs incorrect.

What am I doing wrong or missing here?
 

RobMcM

Active Member
I tried it the other way round - calibrated the black levels to the output of the Oppo, then “fixed” the Kodi output (which was now far too bright) by lowering the brightness in the Video settings during playback and saving as default for all media.

I now have a picture I’m happy with, but I’m still curious if this is the “correct” thing to do or not. Any opinions out there?
 

IvanFraser

Member
I tried it the other way round - calibrated the black levels to the output of the Oppo, then “fixed” the Kodi output (which was now far too bright) by lowering the brightness in the Video settings during playback and saving as default for all media.

I now have a picture I’m happy with, but I’m still curious if this is the “correct” thing to do or not. Any opinions out there?
I don't have the same kit as you but do have br and windows pc to tv via hdmi, set calibrated with Calman. Both channels are equally correct to black level.
It simply looks like you should be setting your tv's channel for Windows to Full. That's what my Win10 requires.
Try a few online greyscale ramps. You should see a full ramp on Full, but washed out on Normal (limited).
Your Oppo at default will be correct - don't correct to your windows if it doesn't match the Oppo and don't alter the Oppo. Get the Oppo as reference and adjust the tv. You really shouldn't need to alter brightness too much on a modern display, but some presets have odd gamma and black levels can crush. Your best cinema equivalent input should be used.
Another thing to try might be disabling backlight control/fald to a minimum setting to see if it interferes with black level.
 

RobMcM

Active Member
I don't have the same kit as you but do have br and windows pc to tv via hdmi, set calibrated with Calman. Both channels are equally correct to black level.
It simply looks like you should be setting your tv's channel for Windows to Full. That's what my Win10 requires.
Try a few online greyscale ramps. You should see a full ramp on Full, but washed out on Normal (limited).
Your Oppo at default will be correct - don't correct to your windows if it doesn't match the Oppo and don't alter the Oppo. Get the Oppo as reference and adjust the tv. You really shouldn't need to alter brightness too much on a modern display, but some presets have odd gamma and black levels can crush. Your best cinema equivalent input should be used.
Another thing to try might be disabling backlight control/fald to a minimum setting to see if it interferes with black level.
Thanks for such a great response and I think you’re probably right. However, since the TV uses the HDMI input from the AVR and the PC and Oppo both run through that AVR, I don’t have the option for different picture settings for two different sources. At the moment the display is calibrated to the unadjusted output from the Oppo, and the Kodi output is corrected via video settings to give a “correct” image on both low pluge and greyscale ramps.

I agree that the TV gives a correct picture in Windows (ie when viewing the desktop) when set to “Full” as that’s what the Windows drivers are set to output, but Kodi is set on “limited” so I presumed to set the TV to match that as the windows driver on “full” is apparently a pass-through setting. If Kodi is on limited and tv is on full, the blacks are much too washed out.

But yes, video playing in Windows but outside of Kodi eg embedded in a browser definitely looks right with the TV set to “full” to match the driver setting.

All other gubbins - backlight, dynamic xyz - are all off on the TV already.

Again, though, thanks for the reply - much appreciated!
 

IvanFraser

Member
Thanks for such a great response and I think you’re probably right. However, since the TV uses the HDMI input from the AVR and the PC and Oppo both run through that AVR, I don’t have the option for different picture settings for two different sources. At the moment the display is calibrated to the unadjusted output from the Oppo, and the Kodi output is corrected via video settings to give a “correct” image on both low pluge and greyscale ramps.

I agree that the TV gives a correct picture in Windows (ie when viewing the desktop) when set to “Full” as that’s what the Windows drivers are set to output, but Kodi is set on “limited” so I presumed to set the TV to match that as the windows driver on “full” is apparently a pass-through setting. If Kodi is on limited and tv is on full, the blacks are much too washed out.

But yes, video playing in Windows but outside of Kodi eg embedded in a browser definitely looks right with the TV set to “full” to match the driver setting.

All other gubbins - backlight, dynamic xyz - are all off on the TV already.

Again, though, thanks for the reply - much appreciated!
I think I see your limitation is using the 1 setting at avr to fulfil 2 different specifications.
You've got 444 signal out and an rgb with full range spec, but output by the software as limited, which is going to be also output over the 1 cable in the 1 format.
So only 1 or the other is going to be 'correct' at any one time?
I had a difficult time with my video in windows to my tv until I realised how much of the software of various programmes were affecting the output. I tried several players, including PowerDVD, PotPlayer etc. They seemed to be putting out limited video over my Full Windows-tv setup.
I tried calibrating the apps and all sorts of things. Couldn't get it right, only near at best.
I ended up with the standalone VLC, installed at its default settings, and it seemed to realise we were using Full all by itself and the picture is great :0) Black level equal to the BR player via the other HDMI. The Windows is through the avr and the br direct to tv though, and therefore both channels are setup individually. PC input via avr set to Full RGB, but the br is plain old 444, so unaffected by the rgb settings, as it doesn't use rgb.
Looks like Kodi is another bit of software that could do with some further development to accommodate whatever it is in VLC that makes it work.
 

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