Source color volume information messaging
Methods are described to communicate source color volume information in a coded bitstream using SEI messaging. Such data include at least the minimum, maximum, and average luminance values in the source data plus optional data that may include the color volume x and y chromaticity coordinates for the input color primaries (e.g., red, green, and blue) of the source data, and the color x and y chromaticity coordinates for the color primaries corresponding to the minimum, average, and maximum luminance values in the source data. Messaging data signaling an active region in each picture may also be included.
1. A method in a decoder to extract source color volume information of an input bitstream from a supplemental enhancement information (SEI) message, the method executed on a processor, the method comprising:
receiving an SEI message comprising one or more source color SEI parameters, the one or more source color SEI parameters comprising color primary component parameters and luminance value parameters;
for a color primary component c, extracting x and y chromaticity coordinates from the color primary component parameters, wherein the x and y chromaticity coordinates define, respectively, normalized x and y chromaticity coordinates of the color primary component c of the input bitstream; and
extracting a minimum, a maximum, and an average luminance value from the luminance value parameters, wherein for one or more coded video pictures in the bitstream that are encoded in a letterbox format, the minimum, the maximum, and the average luminance values are for an active region of the one or more coded video pictures in the letterbox format.
2. The method of claim 1 , further comprising generating an output video signal based on the input bitstream, the x and y chromaticity coordinates for the color primary component c, and the minimum, the maximum, and the average luminance value.
3. The method of claim 1 , wherein the x and y chromaticity coordinates are specified in increments of 0.00002, according to the CIE 1931 definition of x and y as specified in ISO 11664-1.
4. The method of claim 1 , wherein for describing color volumes that use red, green, and blue color primaries, c=0 corresponds to the green color primary, c=1 corresponds to the blue color primary, and c=2 corresponds to the red color primary.