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Old 14th December 2015, 19:38   #34643  |  Link
madshi
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Join Date: Sep 2006
Posts: 9,140
Quote:
Originally Posted by nevcairiel View Post
Note however that not all UHD Blu-rays will use HDR, in fact most will not.
I'm not sure about that. I've some content that is mastered at 1200 nits with DCI-P3. I could imagine that something like this might be suitable for any old and new movies. So it's quite possible that all (or most) movies might get HDR transfers. But I don't really know, we'll have to wait and see...

Quote:
Originally Posted by fairchild View Post
How do we know what to set the display peak luminance to?
FWIW, there's no exact science for how these HDR -> SDR conversions work. So the numbers in the settings dialog are rough estimates. Things also depend on the ambient light level in the room and how your display is calibrated. E.g. with a front projection setup, although the luminance is much lower than e.g. 600 nits, you might still get the best image quality by setting your display to 600 or 900 nits. So my recommendation is to simply play some HDR content and let you eyes decide which nits setting in madVR looks best in your setup.

Quote:
Originally Posted by James Freeman View Post
How can you really know in what range the studio mastered their movie? Seen where?
Install a nightly LAV build, then press Ctrl+J and the mastered nits level is displayed.

Quote:
Originally Posted by James Freeman View Post
Judging by what I see with madTestPattern, how did you know what region is more important to compress and what to clip?
With 1200nit mastered content (presumably), the whole range is compressed.
With 4000nit, again practically the whole range is compressed.
Doesn't that mean that the movie will be too dark overall just so that we will be able to see the super bright parts?
As mentioned before, there's not an exact science to this. The content has more range than any display, so there's way around compressing it somehow somewhere. How much to compress and maybe to clip depends on the video encoding luminance and the display peak luminance. I've selected values for each combination which with real world material looked "good" to me.

Quote:
Originally Posted by TheElix View Post
I have switched to Random Dithering and it seems to fix crashes. But at around the same time when it crashed previously now the video hangs up. It appears like the video goes in an endless loop of several frames while the audio keeps playing.
Oh well. Have you tried installing a different GPU driver version? Do you have any funny GPU related software installed/running? If so, try disabling it.

Quote:
Originally Posted by TheElix View Post
Here's the log with the debug OSD: https://yadi.sk/d/QDP2CRqHmDvVi Maybe you can tell why it doesn't go into FSE?
Will look later when I'm back at my development PC.

Quote:
Originally Posted by TheElix View Post
I've downloaded several test videos and tried the new HDR feature. I am currently using a professional NEC P241W monitor which is true 10 bit through DisplayPort cable and is capable of >Adobe RGB coverage and has a preset for DCI color space. I've set the maximum brightness which is 350 cd/m2 for this display and set the white point to 6500K. I used 400 cd/m2 in madVR settings. Well, it works. But I have horrible amount of dropped frames even though rendering is well under 10 ms. It looks like I cannot truly appreciate the difference now since I'm not getting 10 bit without FSE.
Which queue is the first one empty? Probably the decoder queue? 4K HEVC decoding is really demanding!

Quote:
Originally Posted by TheElix View Post
Also, you said that we may choose the maximum luminance between 0-10000 cd/m2, but the lowest I can choose now is 400 cd/m2. Is it intentional?
No, 0 - 10000 is the range each pixel can have, not the range you can choose in the settings. The settings you can choose is which peak luminance your display has. If your display has a peak luminance of 0 nits then its broken because it doesn't display anything at all.

Quote:
Originally Posted by James Freeman View Post
I think the new "display peak luminance" feature only works if your display has a static and unchangable minimum light level (MLL) of the display.
Meaning, it only truly works if you have a FALD (full-array local dimming) display.
If your display can do 4,000nits but keeps the contrast ratio at 1000:1 it simply does not differ from any other SDR TV.

OR, I might be very wrong!
..and madVR actually compress the HDR content to 1000:1 and you should turn your SDR display brightness to max (400nit) to utilize the new feature...?
Huh? No. Contrast got nothing to do with it. If you have a perfect black level, contrast automatically calculates to infinite, regardless of peak white luminance. And MLL got nothing to do with it, either.

Quote:
Originally Posted by Plutotype View Post
What about Dolby Vision support in madVR? Is it something technically impossible to implement?
I neither have any such content nor any technical spec. Also there are no decoders available for that. But my best guess is that it might be compatible to "conventional" HDR. I don't really know, though.
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