- This topic has 15 replies, 3 voices, and was last updated 2 weeks, 5 days ago by
.
-
Posts
-
Hi all,
My old LG C7 OLED TV is pretty inaccurate at low levels, it crushes too much and using the “brightness” control to set the black level is not ideal as controls on that TV are best left untouched to avoid all sorts of side effects (it’s second gen TV, it’s pretty buggy!).
I can see my calibration is bringing up the low lights a lot but I still think the very first few steps are still too low. Is there a way to tell DisplayCAL to spend a bit more time on those first few steps rather than just do 5% or 10%? Can I maybe create a custom greyscale to check?
I can also see an issue with regular SDR content being displayed on an OLED TV where black level is actually black: that content was probably colour graded on non-OLED displays, hence the first few steps of grey were likely brighter just because the display couldn’t do any better – am I mistaken?
BTW, I am talking about SDR content. I’m using a i1 probe and Windows 10.
Thanks!
I can see my calibration is bringing up the low lights a lot but I still think the very first few steps are still too low.
Are they? Did you measure? A true 2.2 or 2.4 power law is very very very dark in the lower end. Even on a 1000:1 IPS display with a reasonably lit room color difference between RGB 0 and RGB 2 could be much lower than ambient light may let you differenciate.
AFAIK ArgyllCMS does not allow custom TRC in calibration, you may request it.
Are they? Did you measure? A true 2.2 or 2.4 power law is very very very dark in the lower end. Even on a 1000:1 IPS display with a reasonably lit room color difference between RGB 0 and RGB 2 could be much lower than ambient light may let you differenciate.
I did I’m afraid. The room is painted black so there are no reflections. With the usual “black level” pattern where 16 is supposed to be black I don’t see anything before 21 (without calibration it starts at 24). I’d normally adjust the brightness control until 16 is black and 17 is barely visible but the C7 is a special kind, the whole calibration setup is basically unusable as it causes side-effects everywhere. Even HDR is crushed, but that I cannot correct so I use a manual “calibration” via an alternative SW which just boosts the low end of the brightness.
Yes, HDMI levels are correct unfortunately.
AFAIK ArgyllCMS does not allow custom TRC in calibration, you may request it.
Too bad. Not even setting the Calibration Speed to low? I believe that between Very high and High it switched from 10 patches to 20? Might be mistaken.
What’s your opinion on the “watching SDR content on an OLED” subject? Do you see what I mean?
Im thinking you need to check HCFR and get under 30% set to the right levels. The things that change low end brightness is contrast, 5% color offsets, RGB offset. You need to do the whole calibration with tv controls and then use displaycal for color managed applications. 5% from your eye to check color clipping is best. I use calman v3 and show the 1 rgb and 50% background 0 and can not see some colors unless 5% is not under 0. I do not have a oled and oled is a very very dark screen at black 0 . It is 0 brightness as 0.
Ben,
As I said the C7 is a special thing – it was an early TV and all calibration controls are “broken”. If you touch them, you have all sort of banding happening. It’ s just not worth touching them.
I’ll see how it looks if I raise the brightness a bit (contrast is for high lights, brightness for low lights) but I believe when I tried the whole panel slightly glows when I set it to 51 from the default 50 – despite many steps over 16 still dark.
I’m also a believer that with DisplayCAL it’s better to let it deal with everything, besides the 100% RGB balance. One reason to use TV controls to do a basic adjustment is that that way anything you watch (including BD players, Netflix etc) will be decent to watch. But again, I was told not to touch the C7’s controls 🙂 LG fixed those bugs on later models.
Apologies – what is SW?
I meant an “alternate software (SW)” but that is for HDR content where DisplayCal cannot help. This thread is about SDR content.
SDR was mode does not do banding. And 10 bit color is better use for color tracking. It is hard to believe 10 bit output would do banding. I did not read about problems touching controls. (1) LG 2017 OLED Calibration Thread and Settings | AVS Forum Here is some help I hope.
SW I was talking about was software like video card controls and gamma adjustments even windows own calibration.
Thanks for googling that for me but if you read carefully the many pages of that thread you’ll also find the many posts I added to discuss this very issue and you’ll also find out why the C7 is better left untouched.
i never mentioned using graphic card or windows adjustments with displaycal or SDR
the signal from the PC has nothing to do with the banding issue, that happens inside the TV. But you’ll find all the answers in the very thread you mentioned since it seems you don’t believe me 🙂
Are they? Did you measure? A true 2.2 or 2.4 power law is very very very dark in the lower end. Even on a 1000:1 IPS display with a reasonably lit room color difference between RGB 0 and RGB 2 could be much lower than ambient light may let you differenciate.
I did I’m afraid. The room is painted black so there are no reflections. With the usual “black level” pattern where 16 is supposed to be black I don’t see anything before 21 (without calibration it starts at 24). I’d normally adjust the brightness control until 16 is black and 17 is barely visible but the C7 is a special kind, the whole calibration setup is basically unusable as it causes side-effects everywhere. Even HDR is crushed, but that I cannot correct so I use a manual “calibration” via an alternative SW which just boosts the low end of the brightness.
Yes, HDMI levels are correct unfortunately.
AFAIK ArgyllCMS does not allow custom TRC in calibration, you may request it.
Too bad. Not even setting the Calibration Speed to low? I believe that between Very high and High it switched from 10 patches to 20? Might be mistaken.
What’s your opinion on the “watching SDR content on an OLED” subject? Do you see what I mean?
ArgyllCMS on “slow speed” takes 96 readings on grayscale, other 256 entries are interpolated. If TV had bad behaved electronics in between there is little you can do. I have not seen a monitor that needs more that 96/256 steps. 12-> 24->48->96 in iterative process depending on Speed setting.
Also it does not matter that you see or don’t see RGB 21, measure it with colorimeter (assuming and old vanilla i1d3). Also try to measure the same with clean VCGT to spot HW problems like that bad black crush due to some inner setting on TV.
If you wish to measure TV behavior without PC you can use a pi generator and HCFR. Pi is set to full levels, TV & HCFR is set to whetever levels you choose.Calibrite Display Pro HL on Amazon
Disclosure: As an Amazon Associate I earn from qualifying purchases.As I said, I did measure the ‘near black’ levels with HCFR and they’re not as they should be. And yes, I know it’s tricky with the calibration loader disabling the calibration when HCFR is detected but I managed to do so. I’m also using MadVR and get the same results there with madTPG
From my understanding I’ve got the best HW settings for that model, other settings just make it worse. See above, I spent quite some time on that calibration thread!
96 steps might help, that is what I wanted to know, thanks!
The loader disables the app and not the vctg. You can measure the RGB whitebalance for the video lut in HCFR. In generator gdi options the is with video lut or without video lut. Sorry I do not believe everything I read. I test things out. There is some truth the signal to the tv from the pc does not matter but there is some it does. The signal matters a lot when it dithered by the drivers. A generator is lot more stable than the pc video card.
Yes but I’m using an HTPC so that’s where the signal is coming from in the end.
I understand what you’re saying and I don’t remember all the reasons behind it but the TV is doing some conversion internally so RGB 8bit should be the best signal FOR THAT TV – other combinations activate some extra processing in the TV which make things worse.
I also have to set the PC ‘NOT’ as a PC on the INPUT ICON on the TV itself as doing that disables some processing (to reduce lag) which massively crushes blacks and adds tons of banding. I spent weeks reading that thread, asking questions, doing tests etc.
the unanimous final response was ‘don’t touch the TV controls’ 😂The loader doesn’t disable VCTG? Oh cool. Anyways yes I’m familiar with the option you mentioned. Again, it reads as expected on a 10/20 steps but ‘near black’ doesn’t read correct.
and I still stand my opinion I mentioned at the beginning: SDR content might be graded on a non-oled TV where true black is not possible hence the ‘blacks’ will render very differently on an Oled panel.
Gamma 2.2 is ok to use for SDR . Use gamma , brightness and checking by eye. The offsets need to be set with a meter but you can turn up the green only just to enough to see green and use the meter to match the blue and red to it. HCFR is a art to get right. Calman 3.1 on Cnet is free and pattern generator shows 1% in all 6 colors plus white. Even does setting tint and color using the red green and blue screen filters. Can change measurements to 40 whitebalance in hcfr to see between each 5%. Hope you get SDR blacks to be good. If they have a tint it is the color display type setting is wrong. keeping things at 0 for 5% is good if meter is wrong.
