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Xbox 360 display "reference levels" (Question for Amir)

post #1 of 43
Thread Starter 
I want to make sure i'm getting the best display for computer graphics from my xbox360, as I use it mostly for gaming rather than video playback. As far as I can tell, the xbox 360 only outputs RGB over HDMI, even when playing DVD (unlike a DVD player that will output YPbPr). The problem is there is two standards for RGB - PC levels where 0 is black and 255 is white, and video levels where 16 is black and 235 is white (0-16 is below black, 235-255 is above white). DVD uses YCbCr video levels, computer graphics are generally RGB at PC levels.

The xbox 360 has 3 options under "reference levels" in display, that seem to have the following effect:

Standard - produces video levels (16-235)
Intermediate - something in between (?)
Expanded - produces PC levels (0-255)

Now what i'm asking is does the xbox 360 natively produce computer graphics at video levels, complete with below black and above white like DVDs, or is it converting computer graphics to video levels by default? Which option should I use if I want to avoid conversion / least banding in video games?

My Samsung TV has two options for RGB over HDMI - normal and low so it can cope with either.
post #2 of 43
Thread Starter 
Why doesn't it offer the following two options for HDMI output?

YCbCr (at video levels)
RGB (at PC levels)

For analogue component output only offer YPbPr (at video levels), and for analogue VGA only offer RGB (at PC levels). This would make it far simpler to set up.
post #3 of 43
Quote:
Originally Posted by cybersoga View Post

I want to make sure i'm getting the best display for computer graphics from my xbox360, as I use it mostly for gaming rather than video playback. As far as I can tell, the xbox 360 only outputs RGB over HDMI, even when playing DVD (unlike a DVD player that will output YPbPr). The problem is there is two standards for RGB - PC levels where 0 is black and 255 is white, and video levels where 16 is black and 235 is white (0-16 is below black, 235-255 is above white). DVD uses YCbCr video levels, computer graphics are generally RGB at PC levels.

The xbox 360 has 3 options under "reference levels" in display, that seem to have the following effect:

Standard - produces video levels (16-235)
Intermediate - something in between (?)
Expanded - produces PC levels (0-255)

Now what i'm asking is does the xbox 360 natively produce computer graphics at video levels, complete with below black and above white like DVDs, or is it converting computer graphics to video levels by default? Which option should I use if I want to avoid conversion / least banding in video games?

My Samsung TV has two options for RGB over HDMI - normal and low so it can cope with either.

I'm not Amir, but I can tell you that the 360 natively renders in RGB 0-255 levels. That is then converted if necessary, to YCbCr at 16-235 levels and sent over component as YPbPr. If you're using HDMI, then you can choose to convert from RGB 0-255 to RGB 16-235, but you shouldn't do that unless your particular TV only accepts 16-235 levels via HDMI RGB.

The choice of expanded or standard levels applies to the VGA output as well.

P.J.
post #4 of 43
Thread Starter 
Thanks P.J. just to confirm, Expanded is the best setting for games then...?

Why on earth is the "standard" setting default and named as such when it takes the native graphics which have a range of 0-255 and compresses it into 16-235, and then outputs RGB with video levels which is non standard for RGB over HDMI (and indeed VGA)?

16-235 should only be default for YPbPr component connections and YCbCr over HDMI (which the xbox 360 doesn't do as far as I can tell).
post #5 of 43
So I have a question. I'm using component at 1080p for my 360. Reference level set to Standard. Gaming looks great. I was using the 360 as a DVD player this weekend and I noticed that blacks looked really washed out and grey compared to same DVD on my HD-A2.

I notice that it says on the reference level setting something along the lines of "this setting will only effect DVD and 480p playback." I notice I get washed out/grey blacks when playing Fable 1 disc, which is also 480p.

So I guess my question is then what is it sending during gaming at 1080p vs DVD/480p playback. I should note to, that my TV has the ability to label inputs as "DVD", "PC", "Game", etc. I know that for some choices that labeling can affect the picture. I am wondering if because I have it labeled as game, it is expecting computer levels and thus when I get the video levels from DVD/480p that is causing the poor black levels?
post #6 of 43
I would highly doubt the input labels make any difference whatsoever. However, the majority of HDTVs certainly do expect different input levels for different inputs. For example, the VGA connection is almost always setup with the expectation that it be fed PC reference levels.

By and large, component inputs should be expecting TV reference levels. The issue is that SD (480i and 480p) and HD (720p, 1080i, and 1080p) are defined using different standards for things like color and luminance. As a result, mixing and matching can lead to weird problems.

See this Wikipedia article, the section "Luma coefficients":
http://en.wikipedia.org/wiki/Rec._709
post #7 of 43
Now I'm all confused. I thought it was the Expanded setting that crushes blacks. I've been using Standard connected by HDMI to a Sony KDL-52W300, do I need to change it?
post #8 of 43
It's about choosing to use expanded or standard and then calibrating to make them correct. Just arbitrarily picking one of them without calibrating is unlikely to get you optimal results. If you don't intend to calibrate, then go with standard since that is most likely to be closer to correct (unless you are connecting using VGA, then expanded is most likely to be closer to correct). There are rare cases where a TV is expecting expanded over HDMI when the 360 outputs RGB, so the best thing to do is have a calibration disc handy and verify you are getting the proper results.

The 360 can actually display either RGB or YCrCb over HDMI, but the user has no input in the matter and the console decides itself.

Quote:
Originally Posted by sirjonsnow View Post

Now I'm all confused. I thought it was the Expanded setting that crushes blacks. I've been using Standard connected by HDMI to a Sony KDL-52W300, do I need to change it?

You are very likely to get crushed blacks with expanded if you don't check and make sure your TV's "brightness" control is set properly with a calibration disc.
post #9 of 43
Thread Starter 
Quote:
Originally Posted by sirjonsnow View Post

Now I'm all confused. I thought it was the Expanded setting that crushes blacks. I've been using Standard connected by HDMI to a Sony KDL-52W300, do I need to change it?

Most TVs will expect RGB to be at PC levels over HDMI, in which case Expanded is the correct setting. There might be a setting on your TV to change this. Blacks will not be crushed in either games or DVDs. Below black on DVDs should not be visible with RGB at PC levels (not that i'd use it as a DVD player, it's DVD upscaling is awful). Video games do not have below black.
post #10 of 43
Thread Starter 
Quote:
Originally Posted by sperron View Post

The 360 can actually display either RGB or YCrCb over HDMI, but the user has no input in the matter and the console decides itself.

Is there any evidence of any of this? I can't get my xbox 360 to output anything except RGB over HDMI.
post #11 of 43
I'm just going by a post made by Amir once long ago. There is no real reason to output digital component instead of RGB for RGB native content at any rate.

Quote:
Originally Posted by cybersoga View Post

Most TVs will expect RGB at PC levels over HDMI

This is not true. It varies by TV model and manufacturer. Since most sources coming in over the HDMI port will be from video level sources (DVD/BD/Cable/sattelite/etc), the average TV will expect video levels coming in over HDMI. The most important thing is to check yourself with a calibration disc. Your brightness control needs to be set correctly whether using either standard or expended. Just selecting one or the other will not magically make your TVs current brightness and contrast settings be the right ones.
post #12 of 43
When using component the expanded setting is a little different than hdmi or vga. It doesn't set the video levels, because component is always 16-235. It just sets the black level at a different voltage for 480p. If your dvds look washed out, switch to expanded. games and hd will look the same and blacks will not be crushe.

Quote:
Originally Posted by BIGJOHNB20 View Post

So I have a question. I'm using component at 1080p for my 360. Reference level set to Standard. Gaming looks great. I was using the 360 as a DVD player this weekend and I noticed that blacks looked really washed out and grey compared to same DVD on my HD-A2.

I notice that it says on the reference level setting something along the lines of "this setting will only effect DVD and 480p playback." I notice I get washed out/grey blacks when playing Fable 1 disc, which is also 480p.

So I guess my question is then what is it sending during gaming at 1080p vs DVD/480p playback. I should note to, that my TV has the ability to label inputs as "DVD", "PC", "Game", etc. I know that for some choices that labeling can affect the picture. I am wondering if because I have it labeled as game, it is expecting computer levels and thus when I get the video levels from DVD/480p that is causing the poor black levels?
post #13 of 43
Thread Starter 
Quote:
Originally Posted by sperron View Post

I'm just going by a post made by Amir once long ago. There is no real reason to output digital component instead of RGB for RGB native content at any rate.

This is not true. It varies by TV model and manufacturer. Since most sources coming in over the HDMI port will be from video level sources (DVD/BD/Cable/sattelite/etc), the average TV will expect video levels coming in over HDMI. The most important thing is to check yourself with a calibration disc. Your brightness control needs to be set correctly whether using either standard or expended. Just selecting one or the other will not magically make your TVs current brightness and contrast settings be the right ones.

Most sources coming in over the HDMI port will be from video level sources (DVD/BD/Cable/sattelite/etc), will be YCbCr. YCbCr over HDMI is always video levels 16-235, this never changes.

RGB over HDMI is usually PC levels 0-255, but can be video levels too (when an option is provided, default is usually PC levels).

This allows the TV to automatically switch to the right levels whether it's being fed YPbPr or RGB, you shouldn't need to keep calibrating your TV.
post #14 of 43
Quote:
Originally Posted by cybersoga View Post

RGB over HDMI is usually PC levels 0-255, but can be video levels too (when an option is provided, default is usually PC levels).

Actually, the video portion of HDMI and legacy DVI are functionally idenitcal. DVI however did not support digital component. DVI was RGB only and most video sources output video levels over RGB. It's only after HDMI finally over took DVI that digital component has become so prevalent. Even back when DVI was the main option, it was hit or miss whether something output or accepted PC levels. Truthfully it was a big mess.

I still have my first Denon DVI upscaling DVD player and it's default output is video levels. Really, outputting expanded levels for video level content is a bad thing since you are hard clipping the BTB and WTW areas as well as repeating digital steps which can introduce banding.

Games on the other hand can be doing anything. There are no standards and it's just a mess in terms of what devs do. Download the NBA 2K8 demo on the 360 and watch what happens to the black level when the game starts up (for some odd reason the darkest black in the game is just a dark gray and you can watch the black to gray transition when the game is initially loading). Games that have brightness/gamma controls in the menu basically admit that they adhere to no standard and you should adjust to suit your tastes. Then there are games with no controls to adjust and you are just at the mercy of whatever the dev decided to do (like NBA 2K8). Still to this day we haven't had a 360 dev speak on what thier options are for rendering levels and output. People are just assuming that devs are rendering to straight PC levels when in fact they may not be. If I was to hazzard a guess, I'd say that NBA 2K8 is actually rendering to video levels, which are then being treated as PC levels and adjusted to video levels a 2nd time by the 360 hardware (in other words someone messed up).
post #15 of 43
Thread Starter 
This should be all sorted out with HDMI - output games at RGB PC levels and output video at YCbCr video levels automatically switching between them as necessary, like another console I might mention. Why can't the xbox 360 do that?
post #16 of 43
You actually want RGB and video component to be the same levels. If you are going to go full RGB, then you really want to stay full RGB for video as well since the calibrations for PC and video levels are likely to differ atleast slightly. Likewise for video levels if that's what you choose. It's better to pick one and calibrate for it so you get a consistent look between content. The biggest difference I found between video and PC levels was the big effect it had on overall gamma (due to extensive use of the WTW areas (236-254) by now PC level content. This can lead to white discoloration (color run outs) with digital sets or overdriving of the phosphurs on CRT/Plasma if your contrast isn't set more conservatively). If you are interested, I posted some data here, here and here from my testing (if you have HCFR, you can download the actual .chc files to view).

There's really no wrong choice as long as you calibrate. If you aren't going to calibrate, then you can only go with the one that is not showing obvious problems like black crush, washed out blacks or discolored whites.
post #17 of 43
Thread Starter 
Quote:
Originally Posted by sperron View Post

You actually want RGB and video component to be the same levels.

If you calibrate your RGB input to match video component levels, whenever you plug a PC into it you'll need to re-calibrate again, not ideal. You are also asking the xbox360 to compress it's native 0-255 computer graphics into 16-235, which can add banding.
post #18 of 43
Thread Starter 
Anyone know if anything has changed with regards to this with the new xbox experience?
post #19 of 43
I don't think that color banding, WTW/BTB crush is actually that big of a deal. I've never been able to tell the difference between extended and standard -- as long as the display can be calibrated to look correct on each setting.

Old PC video cards with poor quality video "overlay" output really did look terrible, which is why VMR9+video levels was such a drastic improvement. However, the Xbox does the video to PC and PC to video levels conversion well enough that I don't think it's a big issue.
post #20 of 43
Thread Starter 
Somebody who already has NXE reported there's a new option for HDMI colour space

"Auto, Source, RGB, YCbCr709 and YCbCr601."

what's not clear is whether it applies the best reference levels (standard/expanded) automatically for the colour space it's outputting.
post #21 of 43
Quote:
Originally Posted by cybersoga View Post

Somebody who already has NXE reported there's a new option for HDMI colour space

"Auto, Source, RGB, YCbCr709 and YCbCr601."

what's not clear is whether it applies the best reference levels (standard/expanded) automatically for the colour space it's outputting.

HDMI colour space and refrence levels are seperate.
So you could set RGB at standard/expanded.
If my memory serves me right. I'l play around next time I boot up my 360
post #22 of 43
Thread Starter 
Quote:
Originally Posted by Ripeer View Post

HDMI colour space and refrence levels are seperate.
So you could set RGB at standard/expanded.
If my memory serves me right. I'l play around next time I boot up my 360

Upto now the xbox 360 has defaulted to outputting video levels for RGB output (the standard reference levels setting), when just about every TV and computer monitor is factory calibrated to PC Levels (expanded) for it's RGB input (Including VGA, DVI and HDMI). This results in a horrible washed out picture - I wonder how many people are looking at this washed out picture and thinking that the picture quality of the xbox 360 is worse than the PS3 and PC.

RGB should default to PC levels. YCbCr should default to video levels. This is what most TV's and monitors are expecting.
post #23 of 43
With my ISF calibrated Panasonic PZ700U Plasma, Expanded crushes blacks. Did we ever figure out what Intermediate does?
post #24 of 43
Quote:
Originally Posted by Ericthemidget View Post

With my ISF calibrated Panasonic PZ700U Plasma, Expanded crushes blacks. Did we ever figure out what Intermediate does?

How much black does it crush? A lot or just a little? When I had a 700u I found that there was always some amount black crush no matter what.

Try outputting ycbcr.
post #25 of 43
isnt YCbCr 16-235 as well?
post #26 of 43
How about new technology which introduce Sony. The blu ray technology. If you plane to purchase any player so my suggest is simple purchase PS3 machine.
post #27 of 43
Quote:
Originally Posted by triin mack View Post

How about new technology which introduce Sony. The blu ray technology. If you plane to purchase any player so my suggest is simple purchase PS3 machine.

You in the right thread?
post #28 of 43
Quote:
Originally Posted by cybersoga View Post

Upto now the xbox 360 has defaulted to outputting video levels for RGB output (the standard reference levels setting), when just about every TV and computer monitor is factory calibrated to PC Levels (expanded) for it's RGB input (Including VGA, DVI and HDMI). This results in a horrible washed out picture - I wonder how many people are looking at this washed out picture and thinking that the picture quality of the xbox 360 is worse than the PS3 and PC.

RGB should default to PC levels. YCbCr should default to video levels. This is what most TV's and monitors are expecting.

I'd say most consumer TVs are calibrated to accept video level on DVI and HDMI in RGB mode. Panasonic TVs are typically designed to accept ONLY video levels in VGA, DVI and HDMI on RGB. So, your assumption above is not correct.

Most games, according to the discovery on the other thread, are natively rendered in video level (for most of them at least). So, setting the reference level to video level is the best pick for XBox 360.
post #29 of 43
Quote:
Originally Posted by sperron View Post

Actually, the video portion of HDMI and legacy DVI are functionally idenitcal. DVI however did not support digital component. DVI was RGB only and most video sources output video levels over RGB. It's only after HDMI finally over took DVI that digital component has become so prevalent. Even back when DVI was the main option, it was hit or miss whether something output or accepted PC levels. Truthfully it was a big mess.

I still have my first Denon DVI upscaling DVD player and it's default output is video levels. Really, outputting expanded levels for video level content is a bad thing since you are hard clipping the BTB and WTW areas as well as repeating digital steps which can introduce banding.

Games on the other hand can be doing anything. There are no standards and it's just a mess in terms of what devs do. Download the NBA 2K8 demo on the 360 and watch what happens to the black level when the game starts up (for some odd reason the darkest black in the game is just a dark gray and you can watch the black to gray transition when the game is initially loading). Games that have brightness/gamma controls in the menu basically admit that they adhere to no standard and you should adjust to suit your tastes. Then there are games with no controls to adjust and you are just at the mercy of whatever the dev decided to do (like NBA 2K8). Still to this day we haven't had a 360 dev speak on what thier options are for rendering levels and output. People are just assuming that devs are rendering to straight PC levels when in fact they may not be. If I was to hazzard a guess, I'd say that NBA 2K8 is actually rendering to video levels, which are then being treated as PC levels and adjusted to video levels a 2nd time by the 360 hardware (in other words someone messed up).

This is one of the most intelligent post I ever heard regarding this. To add to what you are saying, one of my clients is a devoloper for volition games "saints row". He told me they are rendering in video levels, but not all devolopers do. He said they render in video levels because gamea are played on TV not a PC monitor.
post #30 of 43
Quote:
Originally Posted by sperron View Post

Actually, the video portion of HDMI and legacy DVI are functionally idenitcal. DVI however did not support digital component. DVI was RGB only and most video sources output video levels over RGB. It's only after HDMI finally over took DVI that digital component has become so prevalent. Even back when DVI was the main option, it was hit or miss whether something output or accepted PC levels. Truthfully it was a big mess.

I still have my first Denon DVI upscaling DVD player and it's default output is video levels. Really, outputting expanded levels for video level content is a bad thing since you are hard clipping the BTB and WTW areas as well as repeating digital steps which can introduce banding.

Games on the other hand can be doing anything. There are no standards and it's just a mess in terms of what devs do. Download the NBA 2K8 demo on the 360 and watch what happens to the black level when the game starts up (for some odd reason the darkest black in the game is just a dark gray and you can watch the black to gray transition when the game is initially loading). Games that have brightness/gamma controls in the menu basically admit that they adhere to no standard and you should adjust to suit your tastes. Then there are games with no controls to adjust and you are just at the mercy of whatever the dev decided to do (like NBA 2K8). Still to this day we haven't had a 360 dev speak on what thier options are for rendering levels and output. People are just assuming that devs are rendering to straight PC levels when in fact they may not be. If I was to hazzard a guess, I'd say that NBA 2K8 is actually rendering to video levels, which are then being treated as PC levels and adjusted to video levels a 2nd time by the 360 hardware (in other words someone messed up).

Tiger woods 2009 is doing the exact same thing. Opening screen video levels treated as pc levels, then switched back to video levels on the 360. Same old song and dance.
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