Patent ID: 7848412

Claim:
A prediction image generation apparatus for generating a prediction image from encoded data obtained by subjecting a video image having a luminance component and first and second color difference components, to prediction encoding, comprising: a receiver configured to receive an input of encoded data obtained by encoding, for a to-be-decoded block, an index indicating (A) 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 (B) a reference image; a determining module configured to determine whether a decoding unit of the to-be-decoded block is a frame or a field; a deriving module configured to derive the weighting factors and the offsets from the index for the to-be-decoded block; and a generator configured to generate a prediction image by multiplying the luminance and color difference components of the reference image by the weighting factors, respectively, and adding the offsets, respectively, to results of the multiplying; wherein respective values of indexes indicate different combinations when the decoding unit is the frame, and two values of the index corresponding to different reference images indicate an identical combination when the decoding unit is the field.