[fritsch]

Sunflux summarizes everything that makes sense one page back. Lauri explains the technical details. Everything was said - the rest is confusion and BigL did not get it yet :-)

[BigL-New]

Sunflux summarizes everything that makes sense one page back. Lauri explains the technical details. Everything was said - the rest is confusion and BigL did not get it yet :-)

I was so busy writing my own posts and had no time for everybody's explanations ;-)

My only confusion right now is how to distinguish driver level (xrandr) and TV level in cases like mine - TV has no UI for RGB range so i can only set it on driver level and check on the same level (first one and also last one in chain explained by Sunflux). Specially how can i get in this situation best settings according to Sunflux:

Driver 0-255 -> Kodi Limited -> Dithering Off -> TV Limited

I cannot set TV to Limited on UI level, only on driver (xrandr) level. So i can have:

Driver 0-255 -> Kodi Full/Limited -> Dithering On/Off -> TV Full

or

Driver 16-235 -> Kodi Full/Limited -> Dithering On/Off -> TV Limited

[fritsch]

So - your TV just sets what the GPU with xrandr sets, so it reads the INFO Frame and sets the TV accordingly?

Did you verify this? With some Test patterns?

If that's really the case, use:


Driver 0-255 -> Kodi Full -> Dithering On -> TV Full

[Hufvudet]

Sunflux summarizes everything that makes sense one page back. Lauri explains the technical details. Everything was said - the rest is confusion and BigL did not get it yet :-)

Ok, big thanks to Lauri!

Still....at least for me, the question remains: why would we even consider dithering when limited range is kept untouched through the chain? I don't understand which calculations might benefit from dithering in limited range. It's very obvious in full range.

Limited range of course means = kodi limited - gpu full - tv limited.

Is it only me?

[lexi81]

Sunflux summarizes everything that makes sense one page back. Lauri explains the technical details. Everything was said - the rest is confusion and BigL did not get it yet :-)

I was so busy writing my own posts that had no time for everybody's explanations ;-)

My only confusion right now is how to distinguish driver level (xrandr) and TV level in cases like mine - TV has no UI for RGB range so i can only set it on driver level and check on the same level (first one and also last one in chain explained by Sunflux). Specially how can i get in this situation best settings according to Sunflux:

Code:

Driver 0-255  -> Kodi Limited -> Dithering Off -> TV Limited

I cannot set TV to Limited on UI level, only on driver (xrandr) level. So i can have:

Driver 0-255 -> Kodi Full/Limited -> Dithering On/Off -> TV Full

or

Code:

Driver 16-235  -> Kodi Full/Limited -> Dithering On/Off -> TV Limited

Try the different kodi settings in the bold part when you playback the AVS rec709 calibration files. You can check the black and white settings so you can see which is best.

I'm on:
Driver full (0-255)
Kodi full + 8bit dither
TV full

[Roby77]

why someone choose full and other limited ?

It's true as someone wrote

Limited best for video

Full best for picture and good for video ?

[fritsch]

Guys, the next unreflected post here and I will just close it down.

This is not some bikeshedding thread and everybody that currently has no idea what this talk is about - just calm down and reread the last three pages. Thanks you very much.

[lmyllari]

Still....at least for me, the question remains: why would we even consider dithering when limited range is kept untouched through the chain? I don't understand which calculations might benefit from dithering in limited range. It's very obvious in full range.

I can think of three things:

1. After scaling the picture it contains pixels that fall between the original integer values. Dithering allows to keep some of those results.
   
2. YCbCr -> RGB conversion doesn't always give integer results. I'm not sure if dithering or rounding is correct. I'm guessing dithering, but maybe there is a standard that answers this? Granger rainbow might show a difference. Sunflux, would you like to do some more pixel peeping?
   
3. Not really keeping untouched limited range, but.. My original reason for implementing dithering was to give 3dlut and other advanced processing higher effective output precision.
   

If rounding to 8bit precision would leave the picture untouched, dithering won't change it.

Is it only me?

I think it's a good question.



edit: /me hides from fritsch after stirring up more trouble, sorry

[Hufvudet]

Still....at least for me, the question remains: why would we even consider dithering when limited range is kept untouched through the chain? I don't understand which calculations might benefit from dithering in limited range. It's very obvious in full range.

I can think of three things:

1. After scaling the picture it contains pixels that fall between the original integer values. Dithering allows to keep some of those results.
   
2. YCbCr -> RGB conversion doesn't always give integer results. I'm not sure if dithering or rounding is correct. I'm guessing dithering, but maybe there is a standard that answers this? Granger rainbow might show a difference. Sunflux, would you like to do some more pixel peeping?
   
3. Not really keeping untouched limited range, but.. My original reason for implementing dithering was to give 3dlut and other advanced processing higher effective output precision.
   

If rounding to 8bit precision would leave the picture untouched, dithering won't change it.

Is it only me?

I think it's a good question.



edit: /me hides from fritsch after stirring up more trouble, sorry

Thank you for clarifying!

[john.cord]

My only confusion right now is how to distinguish driver level (xrandr) and TV level in cases like mine - TV has no UI for RGB range so i can only set it on driver level...

Did you check this with Test Patterns and cross testing with another device like a ps3 on RGB Limited? Like i said, in my case my GT30 Plasma is fine with System set to Full - Kodi to Limited. The Black Level Pattern is exactly the same on both PS3 and Kodi.

Maybe it is best to put this conversion to a seperate thread...

[BigL-New]

So - your TV just sets what the GPU with xrandr sets, so it reads the INFO Frame and sets the TV accordingly?

It seems so - at least that's how it shows xrandr.

Did you verify this? With some Test patterns?

If that's really the case, use:

Driver 0-255 -> Kodi Full -> Dithering On -> TV Full

I've checked with test patterns and IMHO best settings are:

Driver 16-235 -> Kodi Full -> Dithering On/Off -> TV Limited

Driver 0-255 -> Kodi Limited -> Dithering On/Off -> TV Full

With your proposition (Driver 0-255 -> Kodi Full -> Dithering On -> TV Full) i've total mess with black levels. Whole calibration pattern for black is totally black, i cannot see flashing even levels over 16.

Best one is:
Driver 16-235 -> Kodi Full -> Dithering On/Off -> TV Limited - everything in test patterns is 100% correct. I only cannot see much difference with dithering On/Off (looks the same IMHO).

In such configuration xrandr reports:

Broadcast RGB: Limited 16:235
supported: Automatic, Full, Limited 16:235

and autostart has:

xrandr -display :0 --output $OUTPUT --set "Broadcast RGB" "Limited 16:235"

[AndyFurniss]

Today i tried to find the HDMI Black Level Setting in my TX-P50GT30 (European) and i did not find it too... good to know that it does not exist. In my oppinion the European Model is fixed to Limited Colorspace.

At least not on my TV - you can youse xrandr to check what's available for yours. On mine it reports:

Code:

Broadcast RGB: Full
    supported: Automatic, Full, Limited 16:235

So you can clearly see that both are accepted (at least at input level). Right now HDMI negotiation of Full is forced by autostart (see post #1). But Kodi itself sends Full or Limited - it depends on settings. At least on my TV i can clearly see difference - with Limited colors are washed out. But with Full movies are very dark. Yo can check which settings are best on post nr 1360.

But (IMHO only) best settings are with Kodi set to Full, no dithering, but on TV level setting forced to Limited (usung xrandr). So on my setup autostart looks like this:

Code:

OUTPUT=`xrandr -display :0 -q | sed '/ connected/!d;s/ .*//;q'`
xrandr -display :0 --output $OUTPUT --set "Broadcast RGB" "Limited 16:235"
/usr/bin/kodi --standalone

Just to add to the confusion, my 2010 UK Panasonic plasma also has no settings for HDMI = it expects limited. It also doesn't advertise the right hdmi info frames for range, but both Intel and AMD drivers will still offer the settings as shown in your xrandr output.

What limited is though. is not strictly 16-235 anyway, the HDMI specs allow for over and under, so when the driver is set to limited and squashes to 16 - 235 then it's really doing more than needed. IIRC the HDMI specs say no to 0 and 255, but my TV at least doesn't seem to care. There are also CEA specs to consider, I don't know if they overrule HDMI, but IIRC they still allow for over 235.

[Sunflux]

I've checked with test patterns and IMHO best settings are:

Driver 16-235 -> Kodi Full -> Dithering On/Off -> TV Limited

Driver 0-255 -> Kodi Limited -> Dithering On/Off -> TV Full

With your proposition (Driver 0-255 -> Kodi Full -> Dithering On -> TV Full) i've total mess with black levels. Whole calibration pattern for black is totally black, i cannot see flashing even levels over 16.

Best one is:
Driver 16-235 -> Kodi Full -> Dithering On/Off -> TV Limited - everything in test patterns is 100% correct. I only cannot see much difference with dithering On/Off (looks the same IMHO).

In such configuration xrandr reports:

Broadcast RGB: Limited 16:235
supported: Automatic, Full, Limited 16:235

and autostart has:

xrandr -display :0 --output $OUTPUT --set "Broadcast RGB" "Limited 16:235"

For quality, none of the xrandr Limited modes are best.

In order of best quality working downwards:

#1: Driver 0-255 + Kodi Limited + Dithering On/Off + TV Limited
#2: Driver 0-255 + Kodi Full + Dithering On + TV Auto/Full
#3: Driver 16-235 + Kodi Full + Dithering On + TV Auto/Limited

And those three are the only real viable options. #1 is essentially untouched - the holy grail of video purists everywhere. #2 looks very good, but it's doing a LOT of processing to the image, which means it's what I'd use only if I'm unable to force my TV to accept Limited input on a full-range signal, as is required for #1 to work correctly. #3 is likely to be the default option in Kodi, but it's just as processed as #2 and yet still has minor visible banding, which makes it a very distant third in my book.

Now, will the average person sitting at an average distance from their TV watching typical real-world programming notice any difference between #1, #2 or #3? Probably not. But if we were average, we would not be here in this thread talking about this!

[lexi81]

For quality, none of the xrandr Limited modes are best.

In order of best quality working downwards:

#1: Driver 0-255 + Kodi Limited + Dithering On/Off + TV Limited
#2: Driver 0-255 + Kodi Full + Dithering On + TV Auto/Full
#3: Driver 16-235 + Kodi Full + Dithering On + TV Auto/Limited

And those three are the only real viable options. #1 is essentially untouched - the holy grail of video purists everywhere. #2 looks very good, but it's doing a LOT of processing to the image, which means it's what I'd use only if I'm unable to force my TV to accept Limited input on a full-range signal, as is required for #1 to work correctly. #3 is likely to be the default option in Kodi, but it's just as processed as #2 and yet still has minor visible banding, which makes it a very distant third in my book.

Now, will the average person sitting at an average distance from their TV watching typical real-world programming notice any difference between #1, #2 or #3? Probably not. But if we were average, we would not be here in this thread talking about this!

#1 #2 gave me both the correct black pattern. But #1 gave me light grey in the white pattern up to 250. #2 gave me white above 234. So I chose #2, can anybody shine a light on that? Why does kodi limited give gray in the white pattern.

[Sunflux]

For quality, none of the xrandr Limited modes are best.

In order of best quality working downwards:

#1: Driver 0-255 + Kodi Limited + Dithering On/Off + TV Limited
#2: Driver 0-255 + Kodi Full + Dithering On + TV Auto/Full
#3: Driver 16-235 + Kodi Full + Dithering On + TV Auto/Limited

And those three are the only real viable options. #1 is essentially untouched - the holy grail of video purists everywhere. #2 looks very good, but it's doing a LOT of processing to the image, which means it's what I'd use only if I'm unable to force my TV to accept Limited input on a full-range signal, as is required for #1 to work correctly. #3 is likely to be the default option in Kodi, but it's just as processed as #2 and yet still has minor visible banding, which makes it a very distant third in my book.

Now, will the average person sitting at an average distance from their TV watching typical real-world programming notice any difference between #1, #2 or #3? Probably not. But if we were average, we would not be here in this thread talking about this!

#1 #2 gave me both the correct black pattern. But #1 gave me light grey in the white pattern up to 250. #2 gave me white above 234. So I chose #2, can anybody shine a light on that? Why does kodi limited give gray in the white pattern.

As I mentioned in an earlier post, this is likely the correct behavior and is a result of your TV's processing. With option #1, Kodi is outputting all greyshades from 0 to 255. It's your television that's selecting to display only 16-235, and your television that is expanding 16 down to 0. Kodi has nothing to do with this. Now, most televisions will not normally expand 235 all the way up to 255, because 235 by specification is supposed to remain a light shade of grey on modern screens. What remains above that is commonly called "super white".

Now, the main question: between option #1 and #2, 235 itself is about the same color, light grey, right? It's only that you're seeing even whiter above 235 on #2? Then that's because your TV is either choosing not to, or is unable to, display "super whites" when put into limited mode. The important thing to remember, is that videos do not normally contain meaningful content above 235. Sometimes they can, which is why it's typically recommended to enable "super white" if you can, but it's not a huge issue if you can't.

If whites not being their brightest bothers you, you can adjust the brightness or contrast on your set. You might also want to play around with gamma settings if there are any, which may make the difference between 235 and 255 quite minimal.