Patent ID: 10019814

Abstract:
A method of determining luma values from 4:4:4 RGB video data for encoding chroma downsampled 4:2:0 YCbCr video data into a bitstream. Initial coefficents are determined for a region of a colour space the region being one of a plurality of regions located in the colour space and each region having a plurality of associated coefficients. The determined initial coefficients are applied to an initial image to produce a test image, the test image being a chroma downsampled 4:2:0 YCbCr version of the initial image. A measure of quality is determined by comparing the initial image and the test image. The determined initial coefficients are modified to increase the determined measure of quality. Luma values are determined from 4:4:4 RGB video data for encoding chroma downsampled 4:2:0 YCbCr video data into a bitstream using the modified coefficients.