Originally Posted by SSnarski
I loaded the new lumagan update last night and placed the dpad on 3, watched the new Spiderman Far from Home 4K Disc that released yesterday, the movie was ok not great, but Sony did a fantasic job with the picture quality on this disc, this by far has to be the sharpest 4K disc i have seen on my projection system, i picked up the Dr Strange 4K Disc as well, i will have to watch this one soon, really loved this movie, but now they have added the Atmos track as well can't wait to see and hear the improvements.
I picked this one up today but haven't had a chance to look at it yet. We watched the new Men In Black movie the other night and the picture quality was breathtaking for detail and the HDR really lent a lot to the image. So might be worth checking out!
Originally Posted by Wookii
Thanks Kris - yes that’s what I’m getting at, it would be good to know whether of not, for example if your low ratio effective nits is 300 nits (given a x2 multiplier to your measured peakY of 150nits), the 100nit and below values are being sent to the display 2 nits input to one nit output. I could then put up a 100nit test pattern and presumably measure 50nits off screen?
I don't think that is how it works. He didn't build in a multiplier to everything. BUT, if you had put in that your max is 100 nits for low (which means your measured is about 50 nits) you are essentially building in a 2x multiplier already. Stacey built a 100 nit test pattern into the new 4K disc at my request. It is in the advanced video section. I believe it is one of the last patterns in the list. You could measure there and see.
The problem with setting a generic 2x for everything 100 nit and below is you are assuming that everyone did this with SDR, which isn't the case. Most of my clients want it brighter (most ask for around 20 fL, not 14-16). What Jim is doing is leaving as much range as he can nit for nit, but you have to build in for what will eventually be the curve. And that curve is going to be different depending on how high the content needs to stretch. So if you are putting in a higher display max light, you are getting more nit for nit range before the curve starts, but there isn't a hard fast rule that I'm aware of. I looked at the graphical representation of his curves when I was at his place a month or so ago and you could see the most of the curves were nit for nit for most of the same amount until you got to the really high nit values.
Originally Posted by bobof
This sounds like there could be a case for some new test patterns for testing behaviour of dynamic tone mapping implementations. Perhaps something
could think about for V2 of the UHD disc that is in the works.
I'm imagining several sequences of grey scale windowed patches where somewhere on the screen (I guess as far away from the centre as possible, maybe a border around the edge of the screen) you'd have a significantly sized amount of varying peak nit levels so that you could see what happens to the greyscale patches when the analysed maxCLL / maxFALL from a DTM engine is in operation.
So you could have a 100 nit border with patches from 0-100 nit, a 200 nit border with parches from 0-200 nit, etc. Maybe have peaks of 100, 150, 200, 300, 400, 500, 1000, 2000, 4000, 10000.
That wouldn't work because the patches would all be in the same frame. The only way this would work is if the pattern wasn't fixed and was updating like live video. I gave Stacey the idea of using dynamic MaxCLL/DML values for the 4K disc based on what I saw Panasonic doing with their test disc. Stacey took it a step forward and made it so you could change the actual grade of the content on the fly rather than just the metadata. So you could bounce between different patterns he has using the up arrow to select a different grade, but I don't know how much that will tell you about how the DTM is going to act with real content playing. Since Stacey's montage is a regrade each time, it doesn't work quite the way you'd want for evaluation. It also gets significantly brighter overall with each grade up (APL on his grades are really high). But the Lumagen does a great job with all the graded montages on that disc when I've tested it.