[ZwartePiet]

If I understand this correctly, the big question is whether the GUI is degraded in option 3?

From the Kodi wiki, option 2 seems best if you don't care about BTB/WTW. You have fewer color space conversions (i.e. less banding) and you don't lose anything of value.



EDIT: Removed stuff I'm not sure about...

[stoolzo]

Hi, I have an OLED TV so I'm trying to get BTB WTW for both desktop, gaming, youtube videa and kod, ideally without faffing with any scripts, i much prefer the picture I get from my TV when it outputs in BTB/WTW.

I have this working perfect using DSPLAYER / MADVR but I want to move to Krypton. In option 3 everything is working in KODI KRYPTON but everything outside of KODI is crushed, this is the issue that needs dealing with and its caused by how KODI is managing the colour space, its not really an issue with the GUI at all, I see that now.

What I dont understand is that when I set KODI Krypton as 16-235 i have to set my TV on LOW but when I use KODI DSPLAYER with MADVR set 16-235 my TV is on HIGH which seems to be the correct setting as youtube is not crushed.

it seems to me an extra conversion is going on in Krypton which is why when I have it set KODI Krypton to 16-235 my TV needs to be on LOW to compensate and therefore the desktop is crushed. I can get a decent enough picture by doing this differently by using limited on my GPU but I dont want to take that path.

so, the problem as I see it is that Krypton is setup for video levels and not PC levels whch which is odd as I would have thought most HTPC users would use FULL RGB.

[stoolzo]

ok, i've found the combination of settings which got me started with the request to have a seperate colour space for the GUI, it happens when using RGB limted, not FULL RGB.


If I set the PC as RGB limted, the TV to LOW and KODI to 16-235 everything is right but kodi is washed out, so here are the two scenarios to preserve BTB and WTW.

(A)

Full RGB Desktop GPU
TV setting HIGH
KODI Krypton (16-235) ON

Problem=desktop crushed

(B)

Limited RGB Desktop GPU
TV setting LOW
Kodi Krypton (16-235) ON

Problem=kodi menu washed out.

So, the only scenario I feature request could help with is Option (B) where everything works as it should but the KODI menu is washed out. So I was correct afterall, i'm not losing my mind

What we need is an extra setting for when LIMTED GPU is being used rather than FULL RGB, this would simply darken the GUI and do noting else at all.

[stoolzo]

ok, so there is a problem with scenario B as well. My TV may have a bug but i'm not sure all 4K TV's have it, this is a question i've not yet been able to answer. Most Tv's have different modes, they can sense the incoming data and differenciate between a desktop and a movie, this way varying options can be enabled or greyed out depending on what is required. For instance frame interpoeation is usually greyed out in desktop mode.

To tell what mode you are in info is normally selected and on my LG EF950 OLED it shows 3840x2160@60hz when in desktop mode and when i'm playing say, a 1080p movie it will drop into video mode which will instead show 1080p@24hz or whatever the movie is encoded in.

This should mean that me TV should have two completely seperate profiles for 4k, one for desktop 3840x2160@60hz and another for video mode which on a 24hz encoded movie should show 2160p@24hz.

Well, this doesnt work, there seems to be two modes for 1080p and only one for 4k resolutions. This then means that with my TV set to "HIGH" which is the correct setting for desktop 4k movies are washed out in KODI Krypton.

I have tried every single combination I can think of to get around this whilst maintaining BTB WTW and it just doesnt work. I could however go back to using a 1080p desktop but that defeats the object of having a 4k card, but I also think there will be other issues with that, DPI and maybe even KODI issues.

So I here are my options.


1. sack off Krypton for now in the hope someone writes at DS version of krypton, continue using DSPLAYER and play 4K stuff using an external player.
2. Use Limited RGB but manually set TV to low when playing any 4K stuff.
3 Use full RGB and manually switch TV to low when playing any 4K stuff.

I'll probably stick with 1.

[da-anda]

hmm, if your GPU is set to limited RGB I guess you won't need the 16-253 setting in Kodi, as your GPU is already compensating for that, isn't it?

[stoolzo]

if only it were that simple mate.... colour space is a mine fieild now with 4k, it was much easier to manage with just 1080p, the bug with my TV also makes it even more complicated as I cant get my TV to go into video mode (2160P) without putting the TV in bluray mode, but then it doesnt auto switch profiles at all even based on resolution.

Does anyone know if 4k TV's should indeed have a seperate 2160p mode over 3840x2160 mode?

[brazen1]

You have a problem many of us have. You want to use your display in Video mode and PC mode. (as a pc monitor and as a video player)
Choosing one or the other is your best answer. Modern displays have a setting to set one or the other manually as well as in auto.
There is also yet another setting. Selecting HDMI source input and editing your device type to 'PC'. It essentially matches your display to the windows environment to tackle DPI problems. But, it greys out most settings, adds somewhat of a blur, and I don't find it appealing. It does open up GPU capabilities though. Just sayin'.

Consider this and anyone may correct me as I'm just a consumer and not an expert my any means:

Your display has a Video mode (16-235 = Limited) This is also what all your source material is, cable, satellite, blu-rays etc. YCbCr 4:2:0
Your display also has a PC mode (0-255 = Full) Pc's and devices all use this color space. RGB 4:4:4.

Naturally, since your sources are all limited, you'd think you'd want to set all your hardware to limited so everything matches and there is no over processing anywhere. Except when using windows, it wants to use full. That's the dilemma. So, if you are going to use both, something in the hardware chain has to convert the limited to full. What is the best hardware to do the conversion? Your display. Imo, it handles processing the best.

That being said, I use Full for every setting. My 4k panel, AVR, GPU, and Kodi. I have tried many calibrations. This is what works best for my hardware/software. I (think) there is some post processing going on in the chain. Yes, unnecessary extra conversion which supposedly would lead to source degradation, but I don't see it. Maybe the smart panel is smarter than we think?

YouTube video, pictures, DPI text, etc. all appear fine in windows and I'm pretty picky. Kodi GUI is perfect imo. Video appears BTB and WTW. Black bars in video are as black as black gets fwiw. During testing I always re-calibrated from a disc concentrating on brightness and contrast with all enhancements off. I'm happy with my end results no matter what the white sheet calculation says I should be seeing. Personally, I see no reason the Kodi GUI and videoplayer need separate color spaces via sensing, switches, etc. Others may be thinking further outside the box and I'm missing a possibility that could be opened up though.

If you're intent on attacking this further, I suggest you use a spread sheet since, as you know, this all gets very confusing very fast.

[stoolzo]

You have a problem many of us have. You want to use your display in Video mode and PC mode. (as a pc monitor and as a video player)
Choosing one or the other is your best answer. Modern displays have a setting to set one or the other manually as well as in auto.
There is also yet another setting. Selecting HDMI source input and editing your device type to 'PC'. It essentially matches your display to the windows environment to tackle DPI problems. But, it greys out most settings, adds somewhat of a blur, and I don't find it appealing. It does open up GPU capabilities though. Just sayin'.

Consider this and anyone may correct me as I'm just a consumer and not an expert my any means:

Your display has a Video mode (16-235 = Limited) This is also what all your source material is, cable, satellite, blu-rays etc. YCbCr 4:2:0
Your display also has a PC mode (0-255 = Full) Pc's and devices all use this color space. RGB 4:4:4.

Naturally, since your sources are all limited, you'd think you'd want to set all your hardware to limited so everything matches and there is no over processing anywhere. Except when using windows, it wants to use full. That's the dilemma. So, if you are going to use both, something in the hardware chain has to convert the limited to full. What is the best hardware to do the conversion? Your display. Imo, it handles processing the best.

That being said, I use Full for every setting. My 4k panel, AVR, GPU, and Kodi. I have tried many calibrations. This is what works best for my hardware/software. I (think) there is some post processing going on in the chain. Yes, unnecessary extra conversion which supposedly would lead to source degradation, but I don't see it. Maybe the smart panel is smarter than we think?

YouTube video, pictures, DPI text, etc. all appear fine in windows and I'm pretty picky. Kodi GUI is perfect imo. Video appears BTB and WTW. Black bars in video are as black as black gets fwiw. During testing I always re-calibrated from a disc concentrating on brightness and contrast with all enhancements off. I'm happy with my end results no matter what the white sheet calculation says I should be seeing. Personally, I see no reason the Kodi GUI and videoplayer need separate color spaces via sensing, switches, etc. Others may be thinking further outside the box and I'm missing a possibility that could be opened up though.

If you're intent on attacking this further, I suggest you use a spread sheet since, as you know, this all gets very confusing very fast.

its very easy to miss whether you are losing BTB but I found a quick way. Turn all the lights of an play the black clipping slide. Turn the brightness up a few bars slowly. If simply more bars apear and the blacks remain black as they were before to the left you are getting BTB, if the panel starts to wash out you are not.

I have an OLED TV, trust me getting BTB is essential for watching in the dark with all the lights off which is why I got the OLED, therefore taking the LIMTED route is not for me.

My current workaround works great, I use KODI DS and MADVR so I can control my colour space for playing movies outside of KODI which means I have more control over the conversions. This means that my desktop is correct, youtube and all my movies are all fine, the KODI GUI is also fine.

I could quite happily live with this but I really wanted an all in one solution as I am having to use external players for 4k stuff as MADVR doesnt play nice with 4k, although I will always have to have an external player for 3D MVC stuff as that required LAV filters which are only available in KODI DS, not in KRYPTON obviously.

I actually use two external players, I use MPC-HC configured with LAV filters and MADVR for 3D stuff as 3D will never be more than 1080p and I use MPC-BE for all 4K stuff, again using LAV filters but just the standard renderer not MADVR.

For all 2D 1080p I just use normal KODI DS.

its quite a complex setup which is another reason why I wanted to go Krypton, I guess if nobody can tell me why I cant get my HTPC into 2160p mode I'll just have to live with it

[ZwartePiet]

I don't understand why you are trying the preserve BTB/WTW? It's a holdover from the NTSC system and wasn't designed to contain picture information. EDIT: Looking into this, apparently some "mastered in 4K" Blu-Ray disks use this range for the xvYCC color space. May be worthwhile, but how prevalent are these disks?

I'm not too familiar with OLED TVs, but I highly doubt it needs the BTB content to give you "infinite" contrast. If reference black doesn't give you true black, you probably need to adjust the TV's settings.

Getting the best image quality is really a case of less is more. Start with the best content you can get your hands on -- for Kodi this would be 1:1 Blu Ray rips -- and process it as little as possible. Calibrate your TV (or use ISF Dark picture mode), turn off every image enhancing gimmick, connect Kodi via PC mode to make your TV a dumb monitor, turn off the limited range GUI option, set your video card to RGB full and you're off to the races.

Naturally, since your sources are all limited, you'd think you'd want to set all your hardware to limited so everything matches and there is no over processing anywhere. Except when using windows, it wants to use full. That's the dilemma. So, if you are going to use both, something in the hardware chain has to convert the limited to full. What is the best hardware to do the conversion? Your display. Imo, it handles processing the best.

Kodi converts your content to full RGB so it can composite the GUI. Outputting in limited range would require an additional (unnecessary) conversion.

[stoolzo]

Hi, you'd have to own an OLED to understand really, going LIMTED was the first thing I tried as I cant get 10/12 bit using FULL RGB 4:4:4, you can only get 10/12 bit if you use 4:2:2 YBCR on my system.

I've spent months tinkering and calibrating and i've always come back to FULL RGB as I've always got the best picture. Perhaps if I could afford a professional calibration it might be better but money is tight.

[FernetMenta]

The weak link in this chain is the graphics drivers. They either output full range or a compressed format of limited range that clips BTB and WTW. The work around that suggests to set gfx output to full range and kodi + tv to limited does not work in all cases. HDMI sends an info frame that tells the tv the color range. Most TVs (maybe outdated) do not interpret this info frame but some do (maybe most current models do). If a TV does, it will automatically switch to either limited or full range, regardless of what you set it to.

I got the info that new windowing systems like Wayland on Linux provide a means to get this right. I have no information how ather platforms can cope with this.

[malvinas2]

[...]HDMI sends an info frame that tells the tv the color range. Most TVs (maybe outdated) do not interpret this info frame but some do (maybe most current models do). If a TV does, it will automatically switch to either limited or full range, regardless of what you set it to.[...]

My settings in the Graphic card and Kodi use the full colour range and the TV switches automatically to the desired range. Until now I assumed the TV uses full colour range for the GUI and changes to limited range when playing a video. But if I understand you correctly, the TV will never change to the limited range, because it does not analyze the "colour information", but relies on this 'info frame'. Is this right ?

[ZwartePiet]

The weak link in this chain is the graphics drivers. They either output full range or a compressed format of limited range that clips BTB and WTW. The work around that suggests to set gfx output to full range and kodi + tv to limited does not work in all cases. HDMI sends an info frame that tells the tv the color range. Most TVs (maybe outdated) do not interpret this info frame but some do (maybe most current models do). If a TV does, it will automatically switch to either limited or full range, regardless of what you set it to.

Is there a tangible downside to setting everything to full range RGB? You surely have the deepest understanding of all this, so I'd like to hear your opinion.

I noticed the new VAAPI drivers have dithering as an option when outputting full range RGB, but I don't see why that is necessary? Is banding introduced when expanding the colorspace? I thought it was primarily an issue when reducing bit-depth. Or is it just a way to take advantage of 10-bit displays by hiding the banding inherent in 8-bit content?

[FernetMenta]

The point is that the original "limited" colour space actually is not limited to 16 - 235. Although the reference values for back and white are at 16 and 235 respectively the values below and above are used for so called over/under shots. When you transform from limited to full range foot and headroom values are clipped which can result in issues like banding. Dithering can alleviate this but the preferable option is not to convert from one colour space to another.
As you can see from the post in this thread, there is a lot of confusion in this area. Don't assume that developers of graphics drivers are fully aware about the problem. And even if they know, things can't be changed that quickly.

[ZwartePiet]

The point is that the original "limited" colour space actually is not limited to 16 - 235. Although the reference values for back and white are at 16 and 235 respectively the values below and above are used for so called over/under shots.

I've heard that, but how are people calibrating their TV to display this information? A basic calibration involves setting black and white levels to prevent clipping/overshoot.

When you transform from limited to full range foot and headroom values are clipped which can result in issues like banding. Dithering can alleviate this but the preferable option is not to convert from one colour space to another.

Why aren't these color space conversions done in higher bit-depths? The current method sounds like 219 bits are being spread into a 255 bit container, hence the banding. I agree that color space conversions should be held to a minimum, but they would be less painful if interpolation was used.

As you can see from the post in this thread, there is a lot of confusion in this area.

Yeah, I'm trying to make head-or-tails of it all. My conclusion thus far is that North Korea full range is best Korea range.

The GUI is natively rendered (and looks best) in full range RGB. The content needs to be converted from YUV to RGB anyways for compositing. With interpolation, upscaling limited range 8-bit video to full range shouldn't add visible banding beyond that already contained in the content. BTB/WTW gets lost, but it was never visible anyways. You get to use the PC mode on your television, bypassing as much of its image processing as possible.