Patent ID: 7869519

Claim:
A video encoding method for encoding an input video image to prediction encoding, the input video image having a luminance component and first and second color difference components, the method comprising: deriving, for a to-be-encoded block, an index indicating (A) a reference image and (B) a 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; generating a prediction image by multiplying the luminance component and first and second color difference components of the reference image respectively by the weighting factors and adding the offsets, respectively, to results of the multiplying; generating a prediction error signal by calculating an error between the input video image and the prediction image; generating a quantized orthogonal transform coefficient by subjecting the prediction error signal to orthogonal transform and quantization; and encoding (1) the quantized orthogonal transform coefficient and (2) the index for the to-be-encoded block; wherein two values of the index that correspond to different reference images, respectively, indicate an identical combination of the weighting factor and the offset.