Patent ID: 7869520

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 encoded data obtained by encoding, for a to-be-decoded block, a given number of indices indicating (A) a reference image, and (B) a combination selected from a plurality of combinations, each combination comprising (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; deriving, for the to-be-decoded block, (1) the given number of reference images and (2) (a) the given number of weighing factors and (b) the given number of offsets for the luminance and two color difference components from the given number of indices; and generating a prediction image for the to-be-decoded block by multiplying the given luminance and the first and second color difference components of the number of reference images by the given number of weighting factors corresponding to the respective reference images and adding the given number of offsets, respectively, to results of the multiplying.