Originally Posted by JohnnyBoyPerth
im having some trouble with HDR setup, I feel like the recommended contrast is wrong and can't get a colour space to display the test patterns correctly.
UHD - Panasonic UB-420
AVR - Denon 6200
TV - Panasonic 75ex780
Projector - Epson 9400 (6050 in the US)
The effects are more pronounced on the projector, but still there on the TV. Nothing really looks like the recommended settings you have described. My UHD Player has a ranged of colour space options, the best is RGB 12bit (4:4:4 10/12 looks rubbish, as does 4:2:2 10/12, with test footage they look fine, but not in the calibration patterns) Using 1000nit patterns. 600 looks slightly better, but not by much.
HDR contrast looks to be out when at the recommended default setting, lowering it to around 23 seems to help. This is around the same number I used in SDR calibration so wondering if that's just a really dodgy contrast number and something wrong with the PJ. My TV can be left at the default setting and look ok.
Below are the contrast patterns at 50(default) and 23 that looks ok to my eyes without crazy clipping.
Colour Space Settings
Really struggling with this one, the images below show the best of the colour space in RGB 12bit. But not all colour bursts are showing up clearly in the top two, in other colour spaces I have 4 of the top 6 not really showing. Going close to the screen I can see they are there but not very bright or how they should be shown.
Clipping is hard to see in this picture but 3/4 are correct, with right-most one not showing very well.
Tracking is not good, always seeing the grey bars (better on my TV but still see the darker grey bars)
Colour space conversion - always have more green squares showing than red squares. Same on both PJ and TV
Banding - Have very visible blue banding on PJ and TV, red looks find on both.
Any ideas about what to do, been trying every colour space combination possible and they don't really look that good at all. I have tried connecting the UHD Player direct to PJ/TV and same results. Also copied one of the colour space test pattern onto my media player and shows similar results (thought it might be BD player). I have verified that the projector/tv is receiving HDR signal.
Thinking about just paying someone to calibrate everything
Any help would be apricated
All of the sample images in our articles are for SDR. We can't really show HDR on a web page or in print since HDR is not supported in those cases. SDR uses a relative curve. The blackest your display can do is mapped to 64 and the brightest is mapped to 940. In HDR, it is absolute. So the blackest your display can do is mapped to the code value for that black level and everything below it may be clipped. Same for the top end, except this is where tone mapping comes in. The displays have to follow the curve up to a certain point and then begin to roll everything off to try and fit the remainder it into the same space up to the limit of your display. If they start the roll-off early, and take it slow, they can better distribute the code values above your displays capability and it does not look as clipped. If they try and follow the curve as high as possible and then roll off, then it will look clipped. It is always a compromise.
Until a true 10,000 nit HDR display exists, the patterns will never display correctly. This is why we say not to touch contrast in HDR, it simply lowers the light output and should not bring back any detail.
Projectors really don't go much above 100 nits. The code value for 100 nits is 509. So everything from 509 to 940 must be mapped into 509. A projector probably needs to start rolling off around 10-20 nits. So in this case, everything from say 20-10,000 must be mapped into what your display can do. 20 nits is code value 377. So everything from 377 to 940 must be mapped into 509. Lots of assumptions here.
An OLED is usually spec'ed at 700 nits. Some go higher and so go lower. They should probably start their roll-off around 200-300 nits. I know one brand of OLED that tracks PQ much higher and their highlights look more clipped. A couple of others start much sooner. I can't say one is right and one is wrong since there is no standard for tone mapping HDR. I can say that Dolby Vision's tone mapping manages to preserve everything up to 940 nicely.
The PQ tracking boxes use a single pixel checkerboard. They are an approximation because some displays can't resolve single pixel checkers, like LCoS. The best way to know is to measure the display using software and a colorimeter. I have a Sony Z9D LCD and an LG C9. The C9 handles single pixel checker just fine with the Sony does not. We have also looked at the Sony OLEDs and they are just like the Z9D. So some LCDs can handle single pixel checker and some cannot. Same for OLED. I have a Samsung DLP projector and its single pixel is perfect. It is an HD SDR display though, so only HD patterns can be used on it to evaluate single pixel checker.
Long story short, in SDR, you want to see all the boxes, in HDR you can't until you have a true 10K display.
We have added a lower nit level option for projectors on the future update based on feedback from Kris Deering, which we consider a projector guru. Myself, I am dumping the projector for an 88" OLED. A bit smaller, but I want HDR in my theater.
The banding you see in blue is because something is clipping in YCbCr before converting to RGB. That is bad practice. If they are going to clip, it should be done after conversion to RGB.
For the color space conversion. I have not seen a single consumer display show that correctly in HDR10. I have seen it show correctly in SDR and Dolby Vision. I have also seen it shown correctly on the Sony X300 grading monitor in HDR10.
Normally you want to output YCbCr in 4:2:2 or 4:4:4 at 10 or 12-bit. RGB should be avoided in most cases. The reason is the first thing a display does with RGB is to convert it back into YCbCr and often 4:2:2 since some steps in the pipeline are often limited to 4:2:2 to save money. I would use 10-bit 4:2:2 as a starting point.
Looks like your LCD is rated at 400 nits. The 600 nits patterns would be the closest to that range and is what I would use. 400 nits is code value 636 in 10-bit to give you an idea. I would not pull contrast down from default in HDR mode on it. You will get less than 400 nits.
How do the same patterns in SDR look on your displays?
The Panasonic player should be fine. I have the UB900 and 9000.