Patent ID: 7876826

Claim:
A video decoding method for decoding encoded data obtained by subjecting a video image to prediction encoding to the video image, the video image having a luminance component and first and second color difference components, the method comprising: receiving an input of encoded data obtained by encoding, for one or more to-be-decoded block, a plurality of combinations each comprising (a) a first weighting factor for the luminance component, (b) a second weighting factor for the first color difference component, (c) a third weighting factor for the second color difference component, (d) a first offset for the luminance component, (e) a second offset for the first color difference component, (f) a third offset for the second color difference component, and (g) a flag indicating presence or non-presence of the weighting factors and the offsets for the first and second color difference components and encoding, for a to-be-decoded block, (1) a quantized orthogonal coefficient of a prediction error signal for the luminance component and the first and second color difference components, (2) information of a motion vector and (3) an index indicating a combination selected from the plurality of combinations; deriving, for the to-be-decoded block, the weighting factors and the offsets from the index and the plurality of combinations; generating a prediction image by multiplying the luminance component and the first and second color difference components of a reference image by the weighting factors, respectively, and adding the offsets, respectively, to results of the multiplying, based on the motion vector; generating the prediction error signal by subjecting the quantized orthogonal coefficient to inverse quantization and inverse orthogonal transform; and generating a decoded image signal by calculating a sum of the prediction error signal and the prediction image.