Originally Posted by LTD_666
If I use a contrast level such that the targets clip to 4000 ... would not a dark image remain?
Not if you have at least 100nits peak brightness and are using one of my curves. If it's one of yours, you're on your own
Originally Posted by DVD MAN
Found this on the Calman Forum might help you out.
Stacey Spears wrote:
This sounds like a tone mapping problem with your projector. Note that HDR projection is not really a thing, which is why you are having trouble.
Lupin 3rd wrote:
Someone tells that only discs coded to 10'000nits uses all 1024 levels .... is it real? the other do not use all 1024 levels.
Is there any document that list all the coding mode and levels lost?
Yes it is real. Nothing would use 1024 levels though as 64-940 is the range that is used. 940 is 10,000 nits. Content is being mastered at 1,000 and 4,000 nits. 1,000 nits on the Sony BVM X300 and up to 4,000 nits on a Dolby Pulsar. The max code value used it based on the max nit level.
Just for your info:
100 nits is code value 509.
1,000 nits is code value 722.
4,000 nits is code value 854.
The majority of the picture information is under 100 nits or 77-509. Notice I use 77 instead of 64, this is because black on the mastering display has been 0.005 nits and not 0 nits. 0.005 is code value 77.
In the end, the display tone mapping algorithm handles the differences. You calibrate your display to its max capability. Then the display handles the rest. You don't adjust brightness or contrast to fix the content. Some displays have good tone mapping and some have poor tone mapping. I have a Sony Z9D and it has great tone mapping. The content has HDR metadata associated with it. This data should be passed to the display so it can know how to deal with the different mastering levels. This is not something you will do in calibration. You don't want to calibrate per disc anyway, that would be a nightmare.
With all the respect I have for Stacey, he has no interest in HDR on projectors and he has not seen a properly calibrated picture on an HDR projector (such as with these new curves) yet so he is of zero help here, until he changes his mind and decides to investigate further. Plus in this case he is wrong: according to the metadata (and the picture), half the films are mastered with a black level of zero nits (those mastered to 1000 or 1100nits), so do need to resolve down to level 68. The 0.005nits might have been true at the time he posted this, but it's only titles mastered to 4000nits which have this elevated black level during grading, due to the monitor used.
Originally Posted by Javs
It is so mild that it requires a measurement to see. If you can physically see it, you deserve a medal!
Only the Sony's were so bleeding obvious I knew something was wrong.
It is unit dependent, and it takes a while to take place. For some units, you'll get a significant gamma droop OOTB, for other it can take a few hundred hours to develop. When it's bad, gamma goes from 2.4 to as low as 1.8 or lower in the higher end of the curve, which completely kills the dimensionality of the picture. If you can't see it, it's because you haven't seen a unit with gamma droop yet. It's the main reason for the JVC Autocal, and it's usually why I have to run an autocal after 300 to 500 hours. The autocal usually corrects the effect entirely, at least for a while. It's not bulb dependant, it's panel dependant, so replacing the lamp doesn't make any difference.
Originally Posted by stevenjw
Just an update to this comment, I'm not suggesting that everyone rush out and buy a Linker. I'm having several issues getting it to work correctly in my setup. I think CJ is too. It may be an issue with how it works with the Oppo (vs. the Panny), but I'm finding it also frustrating as it affects my HTPC too. I suggest following our posts in the Linker thread
. That's where I'll be addressing issues. For me, the jury is still out with this piece of hardware. I'm not ready to send it back, but I'm also not happy with it either.
Sorry you're having issues with the linker. I have none of these issues, but I have a Panny and the linker is right before the PJ, at the end of the chain. I'm using the bottom input which I find more stable and I've disabled the autoswitch. It's rock solid in this configuration. The only issue I have is a loss of audio after about one hour (if I pause/resume, the sound comes back), which I have reported to HD Fury yesterday after I watched a first movie in full in HDR with the linker in the chain (I'm not 100% sure it's the linker but I never had that before). Apart from that, it's super stable. I hope it's not another incompatibility of the Oppo. HDFury should get to the bottom of it if it's the linker's fault. I need to watch another title (still little time at the moment after last week extravaganza) to see if I can reproduce.