Playstation 3 Full Range RGB over HDMI explanation & test
Jun/099
Introduction
The PS3 is a beast of a system with an unfortunate emphasis on function over ease of use, even people with a fairly hardcore technical background might be baffled by some of the deeper settings, leaving regular consumers to google search and hope for the best information to come up. This is like reaching into a cat’s behind and hoping to find expensive coffee, it’s vaguely possible there will be success but honestly how would you even know?
Yes, I am relating the great wealth of information online in this situation to a cat’s bottom, and content.
If you have found this article then I must assume you are at least somewhat familiar with the process of tuning a high-definition LDC television for your home environment and as such I will not delve into that topic for the sake of keeping this simple, links provided on such topics at the end of the article.
DISCLAIMER
Nothing heavy, I just want to make it clear this is a document for those who want the information and more importantly I did not create the test image. I found it a long time ago, and have simply kept it handy to test televisions. You can find it online with Google Image Search so I imagine there is no harm providing another location for it.
Although I can see no method of damaging equipment with this image, if it does, you did it and not me.
Other equipment
I am absolutely sure this works for all HDMI connected equipment with a capability to modify the range of RGB, I have only the PS3. I would love to provide information on the Xbox 360 later on but to do so I will need to borrow one. Updates will come if that happens, although this information is generic enough you should be able to apply it elsewhere.
How this works / RGB
As I understand it the Playstation 3 when connected to a television with an HDMI cable will output all “computer” content such as games and other applications like Life with Playstation, Home and VidZone with an RGB signal. Video that comes from DVD, Blu-Ray or AVCHD discs may be shown using RGB or Y Pb / CB Pr / Cr and the user can select which to use or set the function to automatic. Video from the internal hard disk, USB drive or other non commercial disc format such as DivX files appear to be RGB only.
I can not honestly tell you what the difference is between RGB & Y Pb / CB Pr / Cr as it is a far deeper topic, what I can tell you though is that on my Sony Bravia KDL-32V2000 which supports only Limited RGB, Y Pb / CB Pr / Cr video looks identical to Limited RGB and setting automatic appears to select Y Pb / CB Pr / Cr anyway.
That aside I will only discuss RGB from now on in this document.
The Red Green Blue colour system allows for 256 shades of those three primary colours, mixing them in varying gradients to create the colour of each pixel on the screen; 0 represents the total absense of a colour where 255 represents a full presence of it. R0,G0,B0 is black, R255,G255,B255 is white and just to make it clear R255,G128,B0 would be light orange.
The issue is that HDMI equipped HDTV sets until recently were not all capable of showing the full 256 gradients and were limited to a range of 16 to 235 (220 gradients). As you can imagine R16,G16,B16 is fairly dark but it is not absolute black and R235,G235,B235 is rather bright but not quite white.
From what I can work out (given the lack of actual official information) I would have to conclude that when the PS3 is working inside the limited colour space it will take any shade below 16 and push it up so that 16 becomes 0 according to the television and conversely 235 becomes 255 on the bright end. If this is true then the source signal is being compressed into a space with less gradient option and thus less detail will be possible. It does work better than the other option however because when you enable Full Range RGB the PS3 no longer applies this conversion and sends the source to the television as it is, your television however either cannot process or cannot display anything below 16 or above 235 and it simply vanishes from the screen.
The best explanation for this I can offer is when you have a dark but detailed image in limited space, perhaps you can see a face in the shadows which you can just about make out (think The Dark Knight) and all is well but should you push that image across in the full range the face simply vanishes, it is an absolute black area because the details were provided in shades the TV can not show. Similar for very bright scenes.
Many people do not seem to realise this and are adamant that full is simply better because of the face value deeper colours, the ones that are inside the range of the television and could simply be corrected with the televisions colour controls.
How to test your TV
Follow these instructions with your initial RGB range set to Limited. All settings will be performed under:
Settings > Display Settings > RGB Full Range (HDMI)
- You need to take the following image (1920 by 1080 but works just fine at lower resolutions) and without modifying it get it onto your Playstation 3. Use a USB stick or download it in the browser for example.
- With RGB Limited show the image full screen using the Photo menu, best done in a dark room.
- Adjust the brightness of the television upwards until you can see most of, if not all of the 12 smaller rectangles. The rectangles range from R1,G1,B1 to R16,G16,B16 and the background is R0,G0,B0.
The PS3 is pushing these up into a range of 16 onwards and all televisions should be able to show at least most of them, you may need to turn off any automatic black or contrast controls of the TV. - Once you see the rectangles go back to the settings menu and switch the RGB range to Full, you will notice the screen darken a bit.
- Display again the picture. If you still see the rectangles it would appear your HDTV can process and display Full Range RGB over HDMI. You may need to further increase the screen brightness to see them. If this is the case you should leave it enabled to enjoy the full range of RGB and adjust the TV settings accordingly to provide the best picture.
- If you do not see the rectangles even with the screen brightness at max, your television does not support this mode and you need to leave it set to limited or you will lose fine detail in anything shown using RGB. You may wish to check the televisions advanced automatic contrast and correction settings before coming to this conclusion though, a lot of image processing happens in a modern set.
Conclusion / evidence
I cannot explain yet the difference of HDMI RGB vs HDMI Y Pb/Cb Pr/Cr although I do not intend to simply stop looking. For now this article is covering what I intended and I suggest you experiment to see for yourself the amount of detail lost when Full Range is enabled on a television that cannot show it.
Any comments are welcome. I do not mind being told I am wrong, just so long as there is information to back it up, I will modify this page as any relevant information becomes available.
Here is a small gallery of pictures I took using the Batman Begins Blu-Ray to illustrate the huge difference that is not immediately apparent to the user. Pay attention to the detail in dark areas. There are three shots of each paused scene, one for RGB Limited (which my TV supports), one for RGB Full and one for Y Pb / CB Pr / Cr. Since my TV does not support RGB Full you will see a drastic loss of dark details. I used a camera which is of course not ideal but you will certainly see the differences.
Links to further information
Sony PS3 manuals on this topic http://manuals.playstation.net/document/en/ps3/2_60/settings/rgbfullrange.html
Audio Video forums with many experts http://www.avforums.com and http://www.avsforum.com
RGB colour system http://www.latiumsoftware.com/en/articles/00015.php
HDTV tuning (a very large topic) http://gizmodo.com/5098917/how-to-calibrate-your-new-hdtv-and-not-lose-your-mind
22:01 on July 20th, 2009
Hi! very interesting article. I tested on my TV and I’m not sure if RGB full is supported or not.
I did the following: I download the image and set FULL. At first, I saw nothing. Then I changed the PICTURE MODE from DYNAMIC to STANDARD. Nothing… switched to CUSTOM and nothing. Finally, I switched MOVIE and I saw all the blocks.
On RGB FULL colors seems more ‘intense’ but except for the MOVIE MODE, in the rest, the darker areas are BLACK.
22:20 on July 20th, 2009
Hey there, thanks for giving some feedback. The pre-sets that come with your TV are often not the best for actual home use and I highly recommend you look into tuning an HD TV for your environment. It’s actually not hard, just takes some research and a bit of time.
I gather it is not a Sony from the pre-set names (I only have a Bravia to test) but I would assume Dynamic is similar to Vivid on a Sony set which probably makes the colours stand out really brightly, and if that is the case then you can be sure it is not a good setting to use at home because it is designed to catch the eye in a brightly lit shop rather than reproduce accurate colour.
The Movie setting is typically much darker and configured to give a more realistic colour reproduction for film and if you can see all the blocks on that setting then I would have to assume your TV does indeed support Full Range RGB over HDMI and the best thing for you to do next would be to tune the TV under the Custom slot.
Although this will not be the ultimate guide it looks like a good point to start your research:
http://www.cnet.com/1990-7874_1-5108543-1.html
Good luck
17:47 on August 18th, 2009
Your analysis is mostly correct, however you need to make sure the media also supports RGB full and not just the hardware. RGB full will never look good for movies because movies are coded for video levels(16-235) as opposed to games which are coded for PC levels(0-255) but since games graphics can be created on the fly they can use either PC or video levels. So for movies the choice is to use RGB limited or use Y PB/CB Pr/Cr(which is what I use) and for games use RGB Full(if your tv supports it). Movies played in RGB full will have severe black crush.
18:26 on August 18th, 2009
That is interesting, although I think I might of made that point (accidentally perhaps) in the examples where I showed RGB Full, Limited and Y PB/CB Pr/Cr. I was reading into that topic at the time but have not since gone back, not much need to so far. I do however recall that you can have these settings separately, as optical disc based playback on my PS3 defaults to Y PB/CB Pr/Cr where games default to RGB Limited, it appears to be kept in separate config.
Thanks for pointing this out though, I’ll try and stop being lazy, read more and update it. For now, people can see it in your comment.
16:55 on September 18th, 2009
Well done. I’ve spent the better part of two weeks since discovering this function on the PS3 trying to understand exactly what it does and if my TV supports it (BTW – don’t bother calling the TV maker and asking their technical support people, they will have NO idea). This article takes a straight-forward and simple approach to a not-so-simple interaction between the PS3 and HDTV.
I love all the functionality of the PS3 but I sometimes feel like they intentionally don’t explain this as well as they could because it shows how not all HDTV signal is equal; one mans 1080p is another mans 720p (if you need an example try figuring out why the PS3 doesnt output Dolby TREUHD or DTS HDMA).
This is a solid, well thought out effort, and one that is very much appreciated.
17:39 on September 18th, 2009
Well, thank you. I’m glad it helped. I dislike seeing bad information out there on forums and with luck this helps start clearing some up (I intend to write more but have no topics in mind right now).
Keep in mind however these are simply my own conclusions drawn from information I can find, as someone previously commented I have probably missed some info on the whole Y PB/CB Pr/Cr topic – but I was not aiming for that at the time.
05:04 on September 29th, 2009
I want to ask you a question? First when i set limited RGB, my tv can display all 12 rectangles. Then after i changed to full RGB, my tv can only display 9 rectangles with max brightness. So i try to reduce my tv contrast by 15, the result is I can see all 12 rectangles agan (even though not as clear as in limited). So my question is whether my TV support the full RGB?
16:23 on September 29th, 2009
Please keep in mind I am no expert, but based on what you say I would hazard a guess towards yes. However, if you have to modify your television colour settings into some weird place to make all twelve show, it’s probably not really designed with the RGB Full/HDMI in mind. What matters most in the end is how good the picture on the screen looks. No matter how it is being achieved.