1、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 fol
2、lowing new note: NOTE Bit levels “from 0 to 2 N-8 -1” and “from 255 2 N-8to 2 N -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 “2 N-8 ” to “255 2 N-8 -1” (from 1 to 254, for the case of 8-bit encodin
3、g) 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 , B G R 081 0 , , to 081 0 , , , B G R Page 13 Replace the existing Annex A, by the following new Annex A: Annex A (inform
4、ative) 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 B G R , , values after equation (8), or non-linear B G R , ,
5、 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) r C b C , signal: -127/224 to +126/224 (or -0,566 964 to +0,562 500) For the surface
6、 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 b C and r C 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 Y signals
7、 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 0 64 12 8 19 2 25 6 0 0 .5 1 1 .5 2 2.5 3 Y dY Y xvYCC(8) 235 16 255 0 64 12 8 19 2 25 6 0 0 .5 1 1 .5 2 2.5 3 Y dY Y xvYCC(8) 235 16 255
