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More => Old Versions => JRiver Media Center 21 for Windows => Topic started by: Manfred on June 18, 2016, 01:30:10 pm

Title: 4k: Colour Space
Post by: Manfred on June 18, 2016, 01:30:10 pm

I have a new 4K TV  ;D
In the NVIDIA system properties, I have the following:

-Desktop Colour Depth: 32 bit; 
-Initial Colour Space: 12 bpc;
-Colour format: YCbCr420
-Dynamic Output Area: restricted
(hopefully I translated it correct)

In RO HQ (madVR) I have in "properties"

-PC levels (0-255)
-the native display  bitdepth is: 10 bit (or higher)

In the tab "calibration" I have:

-BT.2020
-pure power curve 2.20

Is this a correct setting for 4k or should I change the settings in the NVIDIA settings to:

-Colour format: RGB
-Dynamic Output Area: full range

or something different?

Title: Re: 4k: Colour Space [fixed]
Post by: Manfred on June 19, 2016, 10:56:41 am

I think I can answer my question by myself after reading various information  :). So if someone has the same problem:

In the MC Wiki

http://wiki.jriver.com/index.php/MadVR_Expert_Guide (http://wiki.jriver.com/index.php/MadVR_Expert_Guide)

I found:
"Regardless of what your display accepts, whether it is 16–235 or 0–255, it should be left at 0–255 to avoid having the image appear “washed out”. Typically if you need to send 16–235 to a display, you will use the video card output to set that, not the video renderer. "

-PC levels 0-255 should be set
-My LG display supports 10 bit-> bitdepth: 10 bit
-My LG diplay supports UHD deep Colour using YCbr4:2:0 with bitdepth 8/10 bit for 50, 59.94 and 60Hz refresh rate (from LG manual)-> set YCbr4:2:0 in the NVIDIA settings. Initial Colour space 12 bpc
-BT.2020 should be used

Title: Re: 4k: Colour Space
Post by: RD James on June 19, 2016, 01:45:23 pm

4K is complicated.
If your GPU and display support it, the best option is to output 4K in full-range (0-255) RGB.

However many 4K displays and older GPUs only have enough bandwidth to support 30Hz in RGB.
YCbCr can support 4K60 on these devices using subsampled chroma (4:2:0).
So you are trading resolution for refresh rate.
 
Your display is almost certainly using BT.709 color when sent a regular 4K signal.
BT.2020 color only seems to be used with HDR right now.

Title: Re: 4k: Colour Space
Post by: Manfred on June 20, 2016, 11:42:06 am

There are 4k demos using 10 bit without HDR. So not 100% sure but Bt.2020 does not require HDR to my knowledge and yes 4k is not so easy.
https://en.wikipedia.org/wiki/Rec._2020 (https://en.wikipedia.org/wiki/Rec._2020)

Title: Re: 4k: Colour Space
Post by: RD James on June 20, 2016, 12:11:13 pm

Quote from: Manfred on June 20, 2016, 11:42:06 am

There are 4k demos using 10 bit without HDR. So not 100% sure but Bt.2020 does not require HDR to my knowledge and yes 4k is not so easy.
https://en.wikipedia.org/wiki/Rec._2020 (https://en.wikipedia.org/wiki/Rec._2020)

10-bit video encoding, and content encoded using the BT.2020 colorspace are very different things.
As I said, I'm not aware of any BT.2020 encoded content that's not using HDR.