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. An apparatus to generate source color volume information for an encoded bitstream, the apparatus comprising a processor, wherein the processor:
encodes video pictures to generate an encoded bitstream;
generates a metadata message indicating source color volume information for the encoded bitstream, wherein the metadata message comprises:
normalized x and y chromaticity coordinates of one or more color primary components in the encoded bitstream; and
luminance value parameters comprising a minimum, a maximum, and an average luminance value, wherein the minimum, the maximum, and the average luminance values are for a picture or an active region of one or more coded pictures in the encoded bitstream; and
generates a video stream that includes the encoded bitstream and the metadata message.
2. The apparatus of claim 1 , wherein the normalized 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.
3. The apparatus of claim 1 , wherein the metadata message comprises a supplemental enhancement information (SEI) message.
4. An apparatus comprising a video bitstream stored on one or more non-transitory machine-readable media, the bitstream characterized by:
data representing one or more video pictures in a compressed format, wherein a portion of the data that represents the one or more video pictures in the compressed format comprises:
a metadata message comprising:
a messaging variable indicating the presence of a set of x and y chromaticity coordinates for one or more color primaries for identifying a 2D color gamut of source color volume information of the data in the video bitstream; and
a minimum, a maximum, and an average luminance variable for the data in the video bitstream, wherein the minimum, the maximum, and the average luminance variables are for one or more video pictures or an active region of one or more video pictures in the video bitstream.
5. The apparatus of claim 4 , wherein the metadata message comprises a supplemental enhancement information (SEI) message.