Patent ID: 7860171

Claim:
A video decoding method for decoding encoded data obtained by subjecting a video image to prediction encoding, the video image having a luminance component and first and second color difference components, comprising: receiving encoded data obtained by encoding, for a to-be-decoded block, (1) a given number of indexes each indicating a (A) a reference image, and (B) a combination selected from a plurality of combinations, each combination 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, and (f) a third offset for the second color difference component and (2) a quantized orthogonal transform coefficient of a prediction error signal concerning the luminance and two color difference components; deriving, for the to-be-decoded block, a given number of the reference images, a given number of the weighting factors and a given number of the offsets from the given number of indexes; generating the prediction error signal for the to-be-decoded block by subjecting the quantized orthogonal transform coefficient to inverse quantization and inverse orthogonal transform; generating a prediction image for the to-be-decoded block by multiplying the luminance and the first and second color difference components of the given number of reference images by the weighting factors corresponding to the reference images, respectively, and adding the given number of the offsets, respectively, to results of the multiplying; and generating a decoded image signal for the to-be-decoded block by calculating a sum of the prediction error signal and the prediction image.