IEC_61966-2-4-2006_cor1-2006.pdf

IEC 61966-2-4(First edition 2006)Multimedia systems and equipment Colour measurement and management Part 2-4:Colour management Extended-gamut YCC colour space for video applications xvYCC CORRIGENDUM 1 Page 8 4.4 Digital quantization methods Replace the existing note after equation(7)by the following new note:NOTE Bit levels“from 0 to 2N-8-1”and“from 255 2N-8 to 2N-1”(0 and 255,for the case of 8-bit encoding)are used exclusively for synchronization and are not allowed for storing colour values.Levels from“2N-8”to“255 2N-8-1”(from 1 to 254,for the case of 8-bit encoding)are available.Page 9 5.2 Transformation from xvYCC values to CIE 1931 XYZ values Replace,on page 10,the inequality signs for equations(12),(13)and(14)as follows:From ,BGR0810,to ,BGR0810,From 0810,0810,BGR,to 0810,0810,BGR,to 0810,BGR Page 13 Replace the existing Annex A,by the following new Annex A:Annex A(informative)Compression of specular components of Y signals This annex describes an example method for the dynamic range compression of the specular components that are brighter than white in Y(or Luma)signal.In xvYCC colour encoding,linear BGR,values after equation(8),or non-linear BGR,values after equations(9)to(11)are not limited between 0 and 1.After the YCC quantization(equation(14),the value range will be limited as follows:Y signal:-15/219 to+238/219(or-0,068 493 to+1,086 758)rCbC,signal:-127/224 to+126/224(or-0,566 964 to+0,562 500)For the surface colours,Y signals shall be in the range of 0 and 1,while over-ranged values(greater than 1,0 or smaller than 0,0)in bC and rC are used for storing saturated colours.However,if the specular components that are brighter than white exist in a captured image,there will be pixels with Ysignals greater than“1”.These components should be compressed(or clipped)into the given quantization range.An example for the specular compression method is provided in Figure A.1.NOTE Different proprietary compression methods in either Y components or RGB components are used in practice.Figure A.1 Example for the specular compression method Editors Note(please delete this sentence);Figure A.1 Example of the specular compression method November 2006 06412819225600.511.522.53YdYYxvYCC(8)2351625506412819225600.511.522.53YdYYxvYCC(8)23516255