High dynamic range image signal generation and processing

A method of generating an image signal in which pixels are encoded in N-bit words, the method comprising:

• decoding received high dynamic range pixel values in accordance with a first color representation in M-bit words;
• encoding the high dynamic range pixel values in the image signal of N-bit words according to a second color representation;
• and
• computing an indicator in the image signal of a type of high dynamic range encoding, wherein the indicator is transmitted for specifying which high dynamic range pixel values are encoded and how the high dynamic range pixel values are transformed for display.

An apparatus for processing an image signal, the apparatus comprising:

• a memory;
• at least one processor coupled to the memory, the at least one processor being configured to:
• receive the image signal, a data segment of the image signal comprising one of high dynamic range pixel values in N-bit words according to a first color representation and low dynamic range pixel values according to a second color representation, and for receiving an indicator indicative of a type of high dynamic range encoding of the high dynamic range pixel values, wherein the indicator specifies which high dynamic range pixel values are encoded and how the high dynamic range pixel values are to be transformed for display;
• extract data of the data segment;
• and
• process the data of the data segment as high dynamic range pixel values dependent on the value of the indicator.

A method of processing an image signal, the method comprising:

• receiving the image signal, a data segment of the image signal comprising one of high dynamic range pixel values in N-bit words according to a first color representation and low dynamic range pixel values according to a second color representation;
• receiving an indicator indicative of a type of high dynamic range encoding that specifies which high dynamic range pixel values are encoded and how the high dynamic range pixel values are transformed for display;
• and
• processing the data of the data segment as high dynamic range pixel values or as low dynamic range pixel values dependent on the value of the indicator.