HDMI Enhanced Black Levels, xvYCC and RGB

[admin]

When trying to get the most performance out of your home theater, few things are more important than proper display calibration. Sure, setting up your speakers correctly and room acoustics are important, but if your display is calibrated wrong, even the most clueless of friends are bound to notice. Audioholics has written a wealth of information on tests and calibrations that are more general and that cover a broad range of topics, but this article is more targeted. It has come to our attention that many of you utilizing an HDMI connection might have your black levels incorrectly set. Why the sudden confusion? Options have changed with the introduction of HDMI 1.3 and its tag-along partners: Deep Color and the new xvYCC color space. Read on.

Discuss "HDMI Enhanced Black Levels, xvYCC and RGB" here. Read the article.

 

[Dezoris]

Clint this is one of the best articles I have seen on here.

It is my understanding that some TVs do an RGB conversion process on incoming signals and convert them to xvYCC and some displays don't?

So getting the settings right is based on what you have which is the most confusing part.

This only applies to BluRay disks. I don't think you want DVDs setup on these setting because the color space of DVD does not use xvYCC.

For BluRay

1. You need a display that does 1080p
2. You need a display that supports HDMI 1.3

On BluRay Player
To enable xvYCC support: (Only on HDMI cable and 1.3 spec.)
Enable super-white output.

Color Space:
Set RGB to limited

Ok now here is where it becomes tricky, do you set the output of BluRay signal as RGB or Y Pb / Cb Pr / Cr?

And also on most displays there is an option for setting for HDMI signal.
In the case of the Panasonics there is a normal and expand mode.

So how do you know what is best for your specific display?

 

[patnshan]

My display "accepts" all these signals but am not sure which is right. I currently have mine set to RBG, but after reading this article I am going to change it to the other one.

As for super white, I was told on another forum to turn that off as my display does not support that. I saw no difference either on or off.

Of course, my display is 720p so it may make little difference anyway. As you can see, I am still confused on this

Pat

 

[Dezoris]

My display "accepts" all these signals but am not sure which is right. I currently have mine set to RBG, but after reading this article I am going to change it to the other one.

As for super white, I was told on another forum to turn that off as my display does not support that. I saw no difference either on or off.

Of course, my display is 720p so it may make little difference anyway. As you can see, I am still confused on this

Pat

You have a right to be confused.
You can't use super white/color space discussed unless you are running 1080p and HDMI 1.3.

 

[jeffsg4mac]

Here is a good primer for more advanced calibration if anyone is interested.

http://www.avsforum.com/avs-vb/showthread.php?t=852536

 

[nguyenpqh]

Why does it look better?

I've read Clint's article and it makes perfect sense. But what's bothering me is that I swear the image from HD sources (i.e. blu-rays) look better on my TV when I have it set to support xvYCC. To be precise, I am using a Samsung LN-T4061F connected to a PS3 via a DVIGear HDMI cable. I have the PS3 set to output YCbCr with super-white turned on. Now, when I turn the xvYCC support off from the TV, the image gets brighter, but the colors look washed out. On the other hand, when xvYCC support is turned on, the colors are sharp and vibrant, although some dark areas seem too dark ("black crush"). I thought I might have some peculiar tastes so I asked my friends to give their opinion and everyone seems to like the image better with the xvYCC turned on. Again, this is only for HD (blu-ray) sources. For DVDs, everyones seems to like it more with the setting off, as there is too much "black crush". How do you account for this without saying that me and my friends are blind?

 

[sclawrenc]

xvYCC on or off?

First of all thanks for your great info. I still have a question that maybe someone can help me with.

If I have a tv, reciever and ps3 which all support xvYCC, should I turn on xvYCC? I have read that most DVD/BD don't use the xvYCC anyway, but I would like to know if it's recommended to turn it on or leave it off if all of my devices support it.

Thanks to everyone

 

[Cruise Missile]

http://www.audioholics.com/tweaks/calibrate-your-system/hdmi-black-levels-xvycc-rgb

Hope this helps.


Edit: Wasn't trying to be smart, silly me didn't look at the entire thread first.

 

[wzpgsr]

Any suggestion on a proper pluge pattern to help set black levels on my Apple TV? I have found a downloadable steps and ramps clip, but after conversion to an Apple TV-compatible format, too much of the data was lost for it to reliably display correctly. Thanks for the succinct explanation in this article!

 

[Alex2507]

Thanks for the article. I just wanted to point out that Avia II does have that really black third verticle bar on the far left of the pluge pattern used to set contrast which is black level which Panasonic calls picture. I hope I got all that right and wonder if they will be able to make it anymore confusing by calling one thing even more names in the future.

Anyways, Avia II doesn't tell you what to do with it. They don't even mention that it is there. They talk about the bar on the left being barely visible when the setting is correct. I think it's actually the bar in the middle that should be barely visible and by that time the blacker than black bar is gone. Maybe they added the blacker than black bar for people with sets that could see it but chose not to mention it so as not to confuse the people who could not see it.

Obviously the article is so over my head that it's ridiculous but I thought people might want to know that you don't have to spend the exta money for Avia Pro when Avia II has the third really black bar.

 

[1080man]

Congratulations Clint on a very accurate and well written article about black levels and code ranges.

In order to retain the most accurate representation of the source material it's natural then to assume one would want to stay in YCbCr all the way to the display element. Furthermore, it's likely that the only real _need_ to consider RGB from a DVD/Bluray would be through a DVI interface since, by definition, it doesn't carry YCbCr although it's perfectly capable in doing so from the video perspective.

Would you agree that by presenting a proper CEA861 first extension in a DVI receiver EEDID the source would be fooled to allow the transmission of YCbCr encoded signal through that DVI interface? This would alleviate the need to color-space convert to RGB and hence code ranges in RGB wouldn't matter any more. As it stands now, all players need to convert to RGB when going through a DVI pipe.

 

[Audioholics]

I used to give exact, specific responses, until I witnessed a few manufacturers doing the exact opposite of what was previously considered the norm.

The takeaway (and works with DVI-D as well) is to simply tweak until you see BTB (and it's possibly in some cases you never will). I have yet to see a system that is incorrectly truncated while still showing Below Black information (though I'm sure someone will find a way.)

 

[jaydog67]

First of all thanks for your great info. I still have a question that maybe someone can help me with.

If I have a tv, reciever and ps3 which all support xvYCC, should I turn on xvYCC? I have read that most DVD/BD don't use the xvYCC anyway, but I would like to know if it's recommended to turn it on or leave it off if all of my devices support it.

Thanks to everyone

From what I read in the article, you should turn it(xvYCC) ON if all the components support it. Turn it off if any one item in the chain does not support it.

 

[ckenisell]

Clint,

Sony has this thing called x.v.Color. Is this just a rebranding of xvYCC? Here's the description of x.v.Color from the XBR4 description:

x.v.Color™ technology BRAVIA® HDTV's performance has now advanced to the point that the color range can be defined by limitations in the original video source, rather than the TV. Thanks to the adoption of a newly approved international color standard called xvYCC (an option in the HDMI v1.3 spec and which Sony participated in creating), the color space has been greatly expanded. 1.8 times as many natural colors as existing HDTV signals will now be faithfully reproduced. x.v.Color enabled products can now offer more accurate color reproduction and natural colors beyond broadcast HDTV.

So, if I am understanding your article correctly...

I should set the PS3 to the following:

• Display Settings
  
  [*]RGB Full Range (HDMI) ---------- Limited
  [*]Y Pb/Cb Pr/Cr Super-White (HDMI) ---------- On​

• BD/DVD Settings
  
  [*]BD/DVD Video Output Format (HDMI) ---------- Y Pb/Cb Pr/Cr
  [*]Cinema Conversion ---------- ??????? (I'm going to assume that this has something to do with frame/refresh rates and outside the scope of this discussion, but I wanted to bring it up just in case it has something to do with color space altering.)​

So, from the PS3, I am sending the signal via HDMI 1.3 to and HDMI 1.3 Integra 9.8, but I have it set up to bypass any video processing. I believe it is sending the raw data to the Sony XBR4 unaltered.

I should set the Sony XBR4 HDTV to the following:

• Picture
  
  [*]Advanced Settings
  

  [*]Clear White ---------- High
  [*]Color Space ---------- Standard
  [*]Live Color ---------- Off​
• Video Options
  
  [*]Video Color Space (x.v.Color)
  

  [*]HDMI 1 ---------- x.v.Color​

  [*]RGB Dynamic Range
  

  HDMI 1 ---------- Limited​

 

[Audioholics]

xvColor is xvYCC... but Sony are "Klingons" when it comes to their equipment so I'm not about to confirm your settings... at first glance they look fine (see below). With Sony I have found, however, that this means absolutely nothing... lol.

Without looking, my guess is that "Clear White" is color temperature... Which I would not have at High.

Now you need some test patterns that show Blacker than Black and Whiter than White to test...

 

[bandphan]

What Clint said... Better to get a calibtarion disc and go thru it..This thread discusses your set and some settings. Keep in mind that general settings will help, but until you go through a calibration it will not be its best. Here is a good read ....

http://www.curtpalme.com/forum/viewtopic.php?t=10457

 

[ckenisell]

Thanks Clint and bandphan!

I have the Digital Video Essentials: HD Basics Blu-ray so I'll throw that in and check it out.

I agree that the "Clear White" is a setting that adjusts the color temperature (However, Neutral, Warm 1, Warm 2, Vivid, etc. is the main color temp setting). With Clear White set to High, the whites look more, well, white to me. For instance, with Clear White turned off, a scene with lots of snow has a red-ish tint to it. Setting Clear White to High renders the snow more like real snow (if I were there in real life).

I also have the color bars and RGB filters that came with DVE: HD Basics. However, after watching all of the instructions, I can never get them entirely accurate. And even when I get close, I'm not happy with the colors that get rendered. There are just WAY too many variables in this Sony set and I have no clue how they all effect each other.

It's nice to have all of the adjustment features, but it's very cumbersome. For instance, I can set the "picture mode" (whatever that means) (Vivid, Standard, Cinema, Photo & Custom). Then I can set amount of color, hue, color temp (cool, neutral, warm 1, warm 2), black corrector (who even knows how that works?), Clear White, Color Space, Live Color, and the one that kills me is setting the white balance. And they ALL effect each other in some wicked way shape or form. Of course, these don't include any of the service menu options.

I'll check out the information found in bandphan's link.

Thanks again.

 

[cvearl]

Beautiful work here Clint!

I cannot tell you how much I appreciate this article. It really clears some things up for me.

From your document I am able to determine that my equipment is set up right and I am in fact setting the right level of black through proper use of the Pluge Patterns in DVE HD Basics or even THX's. They both arrive bang on the same.

Since you seem to really know your stuff, I have a question regarding the setting of the next item. White level or Contrast when using the greyscale patterns relative to your document on Digital Di plays in a fully Digital Home theater setup.

I have a Panasonic PZ85u Plasma and a Panasonic BD35 BD player connected to one another with HDMI. I use DVE HD Basics.

That said, lets see if I get this straight. When mastering the Analogue to Digital the whole analogue range of 0 - 255 is scaled down to fit the entire thing into the Digital scale of 16 - 235.

My disk is coded in 16 - 235 YCbCr from that original Analogue 0-255. The signal sent to my TV is 16 -235 and the Pattern on the DVE disk is 16-235 as well and my TV is displaying content as 16-235. The 0-255 is fit within all that headroom and all.

So.

When I am calibrating using the greyscale, I should not see a difference between the 2 blackest bars in the pattern. As in. I should NOT be able to see any below black with my eye. Adjusted that way with Pluge patterns. You explained this.

But when doing the contrast/white level, should the last white bar 5% above white and the second last bar (Nominal Reference White 235) look different as well? Or should you clip that last bar so that the last 2 bars look the same just like we did with the last 2 black bars when lowering brightness to hide the below black. Should we "hide" the above white in that scale by raising the contrast until JUST the very moment the Nominal White bar 235 and that last white bar blend together?

If it's that we are to show them as separate shades with the 5% being maximum white in the scale and the Nominal White 235 just dimmer than it, does that mean that the Analogue 255 White is now digital 235 White in the digital chain?

Please explain if you can.

Thanks.

Charles.

 

[cvearl]

Basically my quesiton above was a spin off of this comment...

""ALL video stored on modern discs, be it DVD or Blu-ray, are stored as YCbCr with a range of 16-235. But, the content is mastered such that 0-255 is present in the tape domain (the SDI stream - D5 archive tape, etc.) It is then captured into a computer and then the computer will decide what to do with it - preferably retaining the extended info (all data from 0-255). This entire range is then compressed into the 16-235 range accepted by DVDs, Blu-ray Discs, etc. When you play that back on a system set to 16-235, you get all the information as it was intended with no gaps. If you mismatch and play back with RGB (0-255) settings, you'll clip off the black and white levels and black will look "dark gray". Additionally, you won't be able to view the Blacker-than-Black images found on most video test discs. ""

If a test pattern like a 22 step reverse grey scale ramp on DVE is adjusted such that the 235 (nominal white) is now a step below nominal white so that the 5% above white is now apparent to your eye. In other words... made to look different/brighter relative to 235. In that case, have you not actually de-calibrated the 235 white and in effect the entire greyscale?

This is what the DVE instructions tell you to do and I am wondering if making 235 the ONLY brightest white in the digital domain the only brightest white with everything above in the so called "clipped" state.

This is where I get confused.

C.

 

[Frank D]

Great Article.

I have a question as to the difference in the following choices on my Sony 550 Blu Ray Player:

It offers 4 choices (other than auto) for video signal output from the hdmi out jack:

YCbCr (4:2:2)
YCbCr (4:4:4)
RGB (16-235)
RGB (0-255)

What are the difference regarding above four choices? What order would you suggest from most favourable to least favaourable to use?

When I tried using the RGB (0-255) I would not get the BTB and WTW signal.

Thanks