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JRVR Video Renderer
Manni:
First of all, thank you very much for exposing the libplacebo parameters in the advanced JRVR settings. This is extremely useful.
I think you asked in one of the threads which parameter it might be useful to add to the GUI, and one of them is definitely knee_adaptation=<0.0..1.0>.
The default of 0.4 crushes highlights details in high nits titles with a projector and 100nits peak, and until now the only way to improve that was to lie about the peak nits (bring it up to 200nits for example), which of course had a negative impact on shadow detail.
I'm still adjusting this but I find that raising this value up to 0.7 or 0.8 adds a lot of depth to the picture and brings back a lot of details in some bright scenes (the trade-off being that we lose some brightness of course).
A good scene to test this is the beginning of chapter 3 in Pacific Rim. With the default 0.4, the cloud details in the sky at the beginning of the pan are completely crushed (again with a peak of 100nits). Adjusting to 0.8 brings back a lot of detail and adds depth to the picture. I still have to explore as this might have some drawbacks otherwise, but it's one parameter that I would expose. I'll let you know if I find others. If anyone has suggestions to address this better with other parameters, I'm all ears.
On another topic, I've found that JRVR has a bad brightness fluctuation issue. This is very visible again especially in high nits titles, such as Mad Max Fury Road. Watch chapter 3 for example, and you'll see that the brightness fluctuation is obvious, at least with a peak of 100nits. I tried to enable/disable the slow HDR peak detection option in the JRVR advanced settings, but that doesn't seem to help. I use spline with 0 contrast and no contrast enhancement.
That really needs to get fixed, because in its current state JRVR is not usable due to this brightness instability.
Note that there is no such brightness instability issue with madVR as long as you select the correct settings in the latest test builds (detail threshold = 1, TM curve= Mercury, brightness adaptation speed much higher than the default, at least double each value, and conservative contrast recovery values, up to log low).
Drybonz:
--- Quote from: Manni on November 13, 2023, 05:10:37 pm ---Note that there is no such brightness instability issue with madVR as long as you select the correct settings in the latest test builds (detail threshold = 1, TM curve= Mercury, brightness adaptation speed much higher than the default, at least double each value, and conservative contrast recovery values, up to log low).
--- End quote ---
Thanks for the heads up on this. I hadn't tried any of the test builds but I installed it and used the settings you listed here... this has fixed the ultra-dark HDR output I was getting with JRVR and the old MadVR. I get a touch of stutter on 4k HDR files now, but they look a lot better and I'll try to tweak the stutter back out. Thanks again.
Manni:
--- Quote from: Drybonz on November 13, 2023, 07:50:44 pm ---Thanks for the heads up on this. I hadn't tried any of the test builds but I installed it and used the settings you listed here... this has fixed the ultra-dark HDR output I was getting with JRVR and the old MadVR. I get a touch of stutter on 4k HDR files now, but they look a lot better and I'll try to tweak the stutter back out. Thanks again.
--- End quote ---
Glad it helped, but let's keep the discussion here on JRVR :)
I only mentioned madVR as it doesn't have this brightness stability issue (with the correct settings).
mattkhan:
there was more discussion on tm advanced params and curves in https://yabb.jriver.com/interact/index.php/topic,136378.msg951450.html#msg951450
there's a desmos link which shows the behaviour of the curve as you vary these params which you may find useful (or not) to try to relate to what you see
Manni:
--- Quote from: mattkhan on November 14, 2023, 04:53:54 am ---there was more discussion on tm advanced params and curves in https://yabb.jriver.com/interact/index.php/topic,136378.msg951450.html#msg951450
there's a desmos link which shows the behaviour of the curve as you vary these params which you may find useful (or not) to try to relate to what you see
--- End quote ---
Thanks, let's pursue the dicussion there as it might be a better place to do so.
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