Patent ID: 7864847

Claim:
A video encoding method for subjecting an input video image having a luminance component and first and second color difference components to prediction encoding, comprising: determining whether an encoding unit of a to-be-encoded block is a frame or a field; deriving, for the to-be-encoded 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; generating 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; 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, for the to-be-encoded block, (1) the quantized orthogonal transform coefficient and (2) the index; wherein a value of the index when the encoding unit is the frame is a value obtained by performing a right arithmetic shift of one bit on a value of the index when the encoding unit is the field that indicates the combination identical to the index when the encoding unit is the frame.