Patent ID: 8576907

Claim:
A method for coding a picture of a wide dynamic range, the method being performed with a video coding system comprising at least an encoder, the method comprising: determining a set of representational quantization parameter (QP) codes for quantizing blocks of transformed pixel values in a picture, the set of representational quantization parameter codes having at least 32 values, wherein the set of representational quantization parameters codes is within a first set of levels; extending the first set of levels of said representational quantization parameter codes into a second set of levels using a non-linear mapping function, wherein the second set of levels is wider than the first set of levels, depends on an image bit depth, and corresponds to a set of determined quantization parameter (QPd) values, and wherein extending the first set of levels of the representation quantization parameter codes comprises a mapping of respective representational quantization parameter codes to corresponding determined quantization parameter values; for a block of transformed pixel values of the picture, selecting a representational quantization parameter code from the set of representational quantization parameter codes; for the block of transformed pixel values of the picture, using the mapping to select a determined quantization parameter value for the selected representational quantization parameter code; and quantizing the block of transformed pixel values, with the encoder, using the selected determined quantization parameter value.