Originally Posted by LarryInRI
Interesting. Janos says that using the HDMI Calibration in the ADC with a 0-255 checkerboard and user menu set at Dynamic, Cell = 20, Contrast = 95 reduces the banding. Or maybe I didn't read his post that carefully. Janos??
I use a 1-235 pattern for the ADC calibration because the debug log says it tries to align the ranges at 4:4 and 940:940 points (divide them by 4 for 8-bit and you get 1-235).
And I doubt it's only a coincidence that only a 1:235 pattern yields perfect 4:4 and 940:940 result, while any other patterns cause some rounding, like 4:2 and 940:941 (I tried 0-255 and 16-235).
This calibration makes the entire 0-255 range available but leaves nothing reserved (there is no clipping with Contrast 95 and SubContrast 128, but clipping starts if I set them any higher, or I go above 128 with any RGB-Gains.)
So, I believe this is the optimal solution.
But Zoyd doesn't need the full 0-255 range like I do (but I also doubt if he needs more peak brightness either).
After the ADC calibration, I leave Contrast and Brightness at their defaults (95 and 55) as well as the SubContrast (128) and I calibrate the Base WB (SM settings but from the TDM) with a small 100% (255) white patch while I am in a reseted Warm2 color tone mode (zero offsets, like Cool mode but Warm2 is more convenient to use after you reset it once because it's default for Movie mode). I start from all-128 and modify only two Gains but I leave everything else at 128 (every Offsets and the highest Gain ; nothing goes above 128, only two gains go below to avoid any clipping).
After this, I use the 10p system to fine-tune the white balance and the tonal response with 20p APL patterns. (I already set the gamma to -3 in the Top Debug Menu before the WP calibration).
And then I finish the Color Space calibration with 92.2% APL patterns.
Here is my custom package: link
* I do not increase the Brightness to compensate for the "virtual black clipping" with negative Gamma settings because I investigated the problem a bit and found out that the very-first gray shade which can show up on the panel (there is a limit what you can do with the spatial-temporal dithering and the first sub-field is very bright to start with...) is somewhere close to the level where it shows up. So, if you force it to show up as video-level 17 (or PC-level 1) you destroy the near-black gradation. It's better to let those few shades go in favor of much better gamma tracking and better subjective impression.
I believe they are only clipped on the other side of the LVDS interface, not by the video processor (but the panel can't produce that dark shades with the spatial resolution threshold, so they get rounded to zero).
Originally Posted by LarryInRI
Maybe I'm not making myself clear. When you use the checkerboard, do you change the SCC Mode to Movie (Standard??) or do you leave it on its default setting of Dynamic?
It's easier to change picture modes while manipulating hidden parameters if you have debug mode serial console access for the display.
You can simply use your remote to change the picture mode. Or there is the "WB Movie" sub menu.
But it doesn't really matter for the ADC calibration.
You don't really need the serial console to carry out this calibration. But it's easier.
You can run the ADC calibration and do the Base WB calibration from the SM and use the Cool color tone with Movie and/or Cal-Day/Night mode(s). (Unless you have non-128 MSubContrast but I don't think so.)