Black levels in film
#1
Hello all,

I love Kodi and I love watching films. However, I noticed a rather strange thing yesterday. When playing films in Kodi the black levels weren't that good. I noticed that the problem was playing films through my receiver. Let me explain how I watch movies.

Nvidia Shield Android TV plays Kodi --> HDMI to my VSX-1130K receiver --> HDMI out to my Samsung EU46JU7000 tv.

If I watch movies that way the blacks are really grey. When I put my Nvidia Shield Android TV (NSAD) directly in my tv the blacks are truly black. So, my conclusion is that the receiver is not correctly decoding the signal sent by the NSAD.

My ACRyan Playon media player is also in my receiver and those black levels are just fine. So there is a problem with my NSAD or Kodi to my receiver.

This could fairly easily be solved if there was an option in Kodi to adjust the colour scheme/contrast levels, but I cannot find that option. Is there a way this could be implemented? Or does anybody else have a solution to my "problem"? I would be very happy if anyone could help me.

Regards,

MiralceTostie
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#2
I'd suggest checking the video processing settings on your AVR first as this must be altering the video signal if the same source device works as expected direct to TV. Many AVRs allow settings to be altered independently on each input too so you could try swapping the connections to see if the issues follow the source or stay on a particular input.
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#3
We have this feature on Linux, Windows, OSX where users can select between limited and full rage color space.
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#4
Hello,

I've tried switching these. I've switched the NSAD with the AcRyan input and it is still grey. So input switching will not help.

About that Linux Windows thing. I'm not sure what you mean.
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#5
depending on the used version of kodi - you might miss this commit

https://github.com/xbmc/xbmc/commit/8aa0...2f25ceb085
AppleTV4/iPhone/iPod/iPad: HowTo find debug logs and everything else which the devs like so much: click here
HowTo setup NFS for Kodi: NFS (wiki)
HowTo configure avahi (zeroconf): Avahi_Zeroconf (wiki)
READ THE IOS FAQ!: iOS FAQ (wiki)
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#6
I've seen the option on Windows Kodi to adjust contrast and brightness. That isn't there in the NSAT version of 16.0 (Beta) Kodi. Will the be implemented? Does anyone know that?

And Memphiz, I am not sure what I can do with that line of code you provided from Github. Could you please explain?
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#7
That all does not help much on a Shield: http://forum.kodi.tv/showthread.php?tid=256143
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#8
Hello all,

I think I have found the solution to the problem. I tested my Nvidia Shield Android Tv (NSAT) at my cousins house to see if the black levels at his tv were good. And they were. My receiver is the Pioneer VSX 1130k, his receiver is the Pioneer VSX 930. So you might say that they are basically the same.

I plugged in my NSAT in his receiver and the black levels were good. The problem lies in the digital video conversion or "V Conv" option in the receiver. Somehow my cousin can change this option from say "auto" to on/off while watching a movie. I, on the other hand, cannot change this during a film. Which seems strange, because the only things we changed were the receiver, tv and hdmi cable.

We saw a really noticable change when turning the "v conv" option from on to off. The black levels were really good once the option was set to off.

So the problem for me is how I can change this option from on to off. I might be able to turn it to off when I movie is not playing and hopefully the device will remember these settings when I want to watch a movie. Does anybody else have knowledge as to why I cannot change these settings while playing a movie and my cousin (which basically has the same model receiver) can't change these settings.

Maybe one more thing to mention is that he has a 1080p tv where I have 4k. Maybe this can interfere with the available options?
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#9
This still didn't fix it.

We noticed today that the black levels were bad when running a movie in 23.976hz or 50hz. When running a movie on 60hz that black levels were great! So the strange thing is that running a movie on 23.976hz makes it run smooth, but has bad black levels. Running a movie on 50hz gives bad black levels and juttering. Running a movie on 60hz gives very good black levels but makes the movie juttering like everyone 4-5 seconds. There seems to be no option to run a movie on 23.976hz and have the good black levels.

I really hope this rings a bell at you. Maybe when you read this you have a bright idea which might help me out.

We also tried an hdmi splitter, but that didn't work. No screen, purplish snow on screen, or I did have a screen (with really good black levels by the way) but then there was no sound. So, for now, there is no ultimate solution to run a movie on 23.976hz, have good black levels and run it in DTS-HD.
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#10
stupid receiver. I'd return it but you can try this:
http://www.avsforum.com/forum/90-receive...st39885946

Quote:To everyone who is having grey blacks, try this, turn off the receiver , then while holding enter button press power button, menus will appear on the screen, there you can select 4k 4:4:4. I did this and my blacks are black as far as 1080p goes.

I know the setting is for 4k but it made a difference in my case. For some reason, 4:2:2 is on by default from pioneer
.

Of course this is not going to fly as a Kodi feature request. It's a bug in the receiver,
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#11
I have talked about how SATV outputs in different colorspaces based on resolution/refresh rate. It is 8-bit RGB Limited, Rec-709 for all 1080p and 2160p24 modes. It is YCbCr 8 or 10-bit 4:2:0, Rec. 709/2020 for 2160p50/60.

You will get incorrect black levels if one of the devices in your display chain doesn't support RGB Limited which is what is happening in this situation.

As for the actual picture quality, it is no different than other popular devices: http://forum.kodi.tv/showthread.php?tid=...pid2221395
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