Patent ID: 7869515

Claim:
A prediction image generation method for generating a prediction image from 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, the method comprising: receiving an input of encoded data obtained by encoding, for one or more to-be-decoded blocks, 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, and (F) a third offset for the second color difference component, (G) a first flag indicating presence or non-presence of the weighting factor and the offset for the luminance component, and (H) a second flag indicating the weighting factors and the offsets for the first and second color difference components and encoding, for a to-be-decoded block, (1) information of a motion vector and (2) an index indicating a combination of the plurality of combinations; deriving, for a to-be-decoded block, the weighting factors and the offsets from the index and the plurality of combinations; and 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.