Hello, Kilroy Hughes: Ø I am just focused on getting wide gamut encoded "right" at this point, but the method HDMI uses to signal color boundaries might be a useful addition in an SEI message (an optional/informative element in the H.264 bitstream). I believe that the design of this metadata originates from Jurgen Stauder at Thomson (dot net). If you've got several weeks of spare time on your hands you may want to study his papers. Ø H.264 has specific VUI (Video Useability Information) parameters that are pitched to the Display Process so it can implement the correct "render intent" e.g. wide gamut. Only thing lacking is a method to signal "which wide?". I am not sure that I understand you. Traditionally, wide color gamut data would be related to some non-standard set of color primaries. There are countless examples of such ad-hoc and real standards, the best known ones are probably AdobeRGB and XYZ. Obviously one must specify the co-ordinates of the 3 primary colors, or else the R',G',B' image data is meaningless. xvYCC image data (or any Y'CbCr data for that matter !) is always referred to the Rec.709 (sRGB) color primaries, therefore for any Y'CbCr vector one can unambiguously calculate the XYZ or (x,y) or (u',v') co-ordinates. Thus the image itself contains everything you need to know about its color gamut. Just find the most extreme colors in the data. Gamut boundary data can only give you some more information about the potential gamut of images, but you can not know if every individual image will ever reach that boundary. I am not sure how that will help you to define the optimum rendering intent for any given (individual) image ? Ø That is a major improvement over MPEG-2, which was designed when the world had one choice (Rec 601), so the bitstream didn't have to deal with these options. I am not sure that Rec.601 specifies any colorimetry, I thought that it only specified the matrix for R'G'B' to Y'CbCr and back. The actual meaning of R'G'B' co-ordinates was standardized in several other places, and that should not include NTSC 1953 anymore. Charles Poynton says that for all practical purposes the color gamut that everybody uses is standardized in Rec.709. xvYCC only extends on that, but in such a way that for the colors inside the original gamut nothing changes. From the point of view of a TV designer, dealing with out-of-gamut colors is not much different from dealing with abnormal settings of the user controls: contrast, brightness and saturation. You have to solve that without the benefit of metadata too. Groeten, -- Jeroen Jeroen H. Stessen Specialist Picture Quality Philips Consumer Lifestyle Advanced Technology (Eindhoven) High Tech Campus 37 - room 8.042 5656 AE Eindhoven - Nederland Office mobex: (27) 99650 VoipBuster: +31.85.785.3611 (VoIP-in to PC) Mobile 1: +31.6.1389.2492 (office gsm) Mobile 2: +31.6.4468.0021 (personal gsm) E-mail 1: Jeroen.Stessen@xxxxxxxxxxx<mailto:Jeroen.Stessen@xxxxxxxxxxx> E-mail 2: Jeroen.Stessen@xxxxxxxxxx<mailto:Jeroen.Stessen@xxxxxxxxxx> Website: www.consumer.philips.com<http://www.consumer.philips.com> From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On Behalf Of Kilroy Hughes Sent: Wednesday, September 16, 2009 22:04 To: opendtv@xxxxxxxxxxxxx Subject: [opendtv] Re: 1080P Question I am just focused on getting wide gamut encoded "right" at this point, but the method HDMI uses to signal color boundaries might be a useful addition in an SEI message (an optional/informative element in the H.264 bitstream). H.264 has specific VUI (Video Useability Information) parameters that are pitched to the Display Process so it can implement the correct "render intent" e.g. wide gamut. Only thing lacking is a method to signal "which wide?". That is a major improvement over MPEG-2, which was designed when the world had one choice (Rec 601), so the bitstream didn't have to deal with these options. ________________________________ The information contained in this message may be confidential and legally protected under applicable law. The message is intended solely for the addressee(s). If you are not the intended recipient, you are hereby notified that any use, forwarding, dissemination, or reproduction of this message is strictly prohibited and may be unlawful. If you are not the intended recipient, please contact the sender by return e-mail and destroy all copies of the original message.