Single layer high dynamic range coding with standard dynamic range backward compatibility

A high dynamic range (HDR) coding process with standard dynamic range (SDR) backwards compatibility, the HDR coding process comprising:

• generating a tone map describing a transformation from data representing a first color component of an HDR video image to data representing a corresponding first color component of an SDR video image on a pixel-by-pixel basis;
• modeling the tone map as a transfer function;
• processing data representing one or more additional color components of the HDR video image using another transfer function to generate data representing one or more additional color components of the SDR video image;
• determining an inverse reshaping transfer function that corresponds to the reshaping transfer function, an another inverse shaping transfer function from the another reshaping transfer function;
• generating a metadata structure describing the inverse reshaping transfer function and the another reshaping transfer function, the metadata structure including:
• a first function describing a mapping of reconstructed SDR samples to HDR samples for a first color component representing luminance;
• and
• a second function describing a mapping of reconstructed SDR samples to HDR samples for the one or more additional color components, where the second function is different than the first function, each representing a representative chrominance;
• and
• encoding the SDR video image to generate encoded video data including the metadata structure.

A high dynamic range (HDR) coding process with standard dynamic range (SDR) backwards compatibility, the HDR coding process comprising:

• generating a tone map describing a transformation from data representing a first color component of an HDR video image to data representing a corresponding first color component of an SDR video image on a pixel-by-pixel basis;
• modeling the tone map as a transfer function;
• determining an inverse reshaping transfer function that corresponds to the reshaping transfer function;
• generating a metadata structure describing the inverse reshaping transfer function including:
• a function describing a mapping of reconstructed SDR samples to HDR samples for a first color component representing luminance;
• and
• encoding the SDR video image to generate encoded video data including the metadata structure.