Patent ID: 10701361

Abstract:
There are provided mechanisms for encoding a picture of a video sequence in a video bitstream. The picture comprises a first block of samples, wherein each sample in the first block of samples has sample values associated with at least a luma color component and a chroma color component. Each color component is assigned a first quantization parameter. The method comprises calculating a quantization parameter change for at least one color component in the first block of samples, with respect to the first quantization parameter, based on statistics calculated from the sample values from at least one color component in a second block of samples. The second block of samples is one of: source samples of the first block of samples and source samples larger than the first block of samples including the first block of samples. The method comprises quantizing at least one transform coefficient of a residual for the at least one color component in the first block of samples with a second quantization parameter, wherein the second quantization parameter is equal to the sum of the first quantization parameter and the quantization parameter change for the at least one color component. The method comprises signaling the quantization parameter change for the at least one color component to a decoder.