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 non-transitory computer-readable storage medium having stored thereon computer-executable instructions which, when executed by a processor, cause the processor to perform operations comprising:
receiving an input video bitstream with color volume metadata comprising source color volume information for the input video bitstream;
if a metadata flag indicates source color primaries metadata is present, then for one or more color primaries, extracting from the metadata x and y chromaticity coordinates defining for each of the one or more color primaries a 2D color gamut of the input video bitstream; and
extracting a minimum, a maximum, and an average luminance value from the metadata, 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 bitstream that are encoded in the letterbox format.
2. The non-transitory computer-readable storage medium of claim 1 , wherein the computer-executable instructions, when executed by the processor, further cause the processor to perform operations comprising: generating an output video signal based on the input video bitstream and the metadata for the source color volume information.
3. The non-transitory computer-readable storage medium 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 non-transitory computer-readable storage medium of claim 1 , wherein the computer-executable instructions, when executed by the processor, further cause the processor to perform operations comprising:
if a second metadata flag indicates luminance color primaries metadata is present, then for the one or more color primaries, extracting from the metadata second x and y chromaticity coordinates for each of the minimum, the maximum, and the average luminance values.
5. The non-transitory computer-readable storage medium of claim 1 , wherein the metadata further comprises a third metadata flag indicating a presence of information related to the active region of the one or more coded video pictures in the input video bitstream.
6. A non-transitory computer-readable storage medium having stored thereon computer-executable instructions which, when executed by a processor, cause the processor to perform operations comprising:
receiving a sequence of video pictures;
encoding one or more of the video pictures to generate compressed video pictures;
generating a metadata message indicating color volume metadata that comprises source color volume information for the compressed video pictures; and
generating an output video bitstream comprising the compressed video pictures and the metadata message, wherein the color volume metadata indicated in the metadata message comprises:
normalized x and y chromaticity coordinates of one or more color primary components in the output video bitstream; and
luminance value parameters comprising a minimum, a maximum, and an average luminance value, 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 bitstream that are encoded in the letterbox format.
7. The non-transitory computer-readable storage medium of claim 6 , 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.
8. The non-transitory computer-readable storage medium of claim 6 , wherein the metadata message comprises a supplemental enhancement information, SEI, message.
9. The non-transitory computer-readable storage medium of claim 6 , wherein the metadata message further comprises:
second x and y chromaticity coordinates for the one or more color primary components for each of the minimum, the maximum, and the average luminance values.
10. The non-transitory computer-readable storage medium of claim 6 , wherein the metadata message further comprises information related to the active region.