2018-02-05, 20:23
Please cherry-pick: https://github.com/xbmc/xbmc/pull/13481 on top, should be even better.
2018-02-06, 15:47
Fritsch, with 18 probably working for me now: Is there a way to turn off Rec.2020 to sRGB conversion? I need it unconverted in order for my 3D-LUT to pick it up.
P.Kosunen, you will be watching the mentioned color conversion and not an extended color range, so of course it doesn't look better. Getting DCI color range to work blows you away, believe me.
P.Kosunen, you will be watching the mentioned color conversion and not an extended color range, so of course it doesn't look better. Getting DCI color range to work blows you away, believe me.
2018-02-07, 00:46
..or could you just give me a hint what to change in the code before compiling to make it treat Rec.2020 as before? I suppose a switch case somewhere that I could swap instructions for? Then I could compile my own version without bothering anyone and finally TEST IT. 
2018-02-07, 10:40
(2018-02-07, 00:46)((( atom ))) Wrote: ..or could you just give me a hint what to change in the code before compiling to make it treat Rec.2020 as before? I suppose a switch case somewhere that I could swap instructions for? Then I could compile my own version without bothering anyone and finally TEST IT.I am not sure how I can say it politely :-) Let me try: What you ask makes absolutely no sense ... you want a wrong conversion that mapped all colors wrong back to add a simple LUT ontop that just adds offsets? Remember the old code did the very same as the new code, but wrong -> by luck BT709 was "nearly" matching, but all others were terribly wrong. Fix the LUT and it will now be correct for everything.
2018-02-07, 14:06
No, of course I want the improved color treatment but for BT709. I want to map that to DCI colorspace, because that is what my projector can show. Not only BT709. DCI-P3 colorspace is what resides in the Rec.2020, which acts as a container for that colorspace until displays will be able to show all Rec.2020. Converting it down to sRGB is fine for all displays that cannot handle more, but mine can and the colors are there. The LUT converts them correctly and also takes care of gamma and brightness, with very fine tuning possibilities for the abilities of a given display.
So what I want to use is: Rec.2020 input, treated as Rec.709 converted to sRGB output. The LUT is aware of that and transforms the color coordinates exactly to where my PJ expects them.
There is nothing wrong about that. I am not the first one to do that. I checked that with Florian Hörch who is deeply into that stuff and I have seen the results, which are very good.
So what I want to use is: Rec.2020 input, treated as Rec.709 converted to sRGB output. The LUT is aware of that and transforms the color coordinates exactly to where my PJ expects them.
There is nothing wrong about that. I am not the first one to do that. I checked that with Florian Hörch who is deeply into that stuff and I have seen the results, which are very good.
2018-02-07, 17:06
(2018-02-07, 14:06)((( atom ))) Wrote: Converting it down to sRGB is fine for all displays that cannot handle more, but mine can and the colors are there.If you connect your display to a Linux box, it can't benefit from what you call "more". Depth is limited to 24 bit. If you compress any other color space into 24bit, it'll result into the same quality as sRGB.
2018-02-07, 17:59
Nope. You don't need the depth to reach the coordinates. You will have less steps between colors, but you will have the colors. I have them at home with Kodi 17 already. Huge difference.
I work in broadcast for 20 years now and trust me, I can tell the difference. Also I recently got to compare against a SONY VW5000ES. It has more light and contrast but it shows the same colors.
I'd appreciate it if you told me the part of code I have to change to make BT2020 treated like it was 709 and let me be the judge of the outcome. Last option for me right now would be switching to windows and madvr but I'd rather stay with Linux.
I work in broadcast for 20 years now and trust me, I can tell the difference. Also I recently got to compare against a SONY VW5000ES. It has more light and contrast but it shows the same colors.
I'd appreciate it if you told me the part of code I have to change to make BT2020 treated like it was 709 and let me be the judge of the outcome. Last option for me right now would be switching to windows and madvr but I'd rather stay with Linux.
2018-02-07, 21:33
Anyway, just came in with a new NVIDIA 1030 and will go the madvr way.
Btw from what I understand the BT2020 conversion kodi 18 now has only does the "color shift" Fritsch mentioned via shaders and nothing more. To get a somewhat correct picture the higher brightness range also has to be compressed and of course it is not linear. Displaying it 1:1 would be a very bad idea on "normal" displays. The "simple LUT" Fritsch mentioned should be a 3D-LUT and does all of these tasks and some more the right way. Its ability to handle complex tasks makes it a standard tool in cinema postprodution.
A very good starting point for research would for example be https://hub.displaycal.net/forums/
There one can find many success stories of people actually doing "the impossible".
Cheers!
Btw from what I understand the BT2020 conversion kodi 18 now has only does the "color shift" Fritsch mentioned via shaders and nothing more. To get a somewhat correct picture the higher brightness range also has to be compressed and of course it is not linear. Displaying it 1:1 would be a very bad idea on "normal" displays. The "simple LUT" Fritsch mentioned should be a 3D-LUT and does all of these tasks and some more the right way. Its ability to handle complex tasks makes it a standard tool in cinema postprodution.
A very good starting point for research would for example be https://hub.displaycal.net/forums/
There one can find many success stories of people actually doing "the impossible".
Cheers!
2018-02-07, 22:52
(2018-02-07, 17:59)((( atom ))) Wrote: Nope. You don't need the depth to reach the coordinates. You will have less steps between colors, but you will have the colors. I have them at home with Kodi 17 already. Huge difference.
I work in broadcast for 20 years now and trust me, I can tell the difference. Also I recently got to compare against a SONY VW5000ES. It has more light and contrast but it shows the same colors.
I'd appreciate it if you told me the part of code I have to change to make BT2020 treated like it was 709 and let me be the judge of the outcome. Last option for me right now would be switching to windows and madvr but I'd rather stay with Linux.
As soon as you compress the gumut to 24 bit, converting back to anything better than sRGB is lossy. In order to get same results as bofore you need a 3dlut for sRGB to dci. Finally, after I will have implemeted considering of hdr metadata, you will get better results as before.
2018-02-08, 02:26
Sorry I lost interest and just set up my new nvidia card under windows with 12 bits straight out of the box. Madvr has all the needed options and I guess I will be very happy for the time being using my all wrong setup.
2018-04-08, 22:20
So digging around and happily using madvr for doing conversion for two month now, I found a post that explains pretty much what I was after in the first place.
For anybody interested in HDR on equipment that is officially not HDR capable: It can easily be achieved, you need three things: A display capable of outputting at least twice the brightness that you'd need for SDR and also capable of DCI P3 color space output. Many older projectors can to both. A software that does the conversion, i.e. madvr. You actually do not need a 10 or 12 bit display. It helps to reduce banding and can display finer variations of color, but both can be achieved using 8 bits and dithering. It turns out that quite a few UHD HDR display are shipped with 8 bit panels.
Nice explanation of what actually happens: http://www.avsforum.com/forum/24-digital...st55624876
Happy reading, well woth it!
For anybody interested in HDR on equipment that is officially not HDR capable: It can easily be achieved, you need three things: A display capable of outputting at least twice the brightness that you'd need for SDR and also capable of DCI P3 color space output. Many older projectors can to both. A software that does the conversion, i.e. madvr. You actually do not need a 10 or 12 bit display. It helps to reduce banding and can display finer variations of color, but both can be achieved using 8 bits and dithering. It turns out that quite a few UHD HDR display are shipped with 8 bit panels.
Nice explanation of what actually happens: http://www.avsforum.com/forum/24-digital...st55624876
Happy reading, well woth it!
