Patent ID: 7876822

Claim:
A video decoding apparatus of decoding encoded data obtained by encoding a video image having a luminance component and first and second color difference components, the apparatus comprising: a receiver configured to receive, as an input, encoded data obtained by encoding for a to-be-decoded block (1) a quantized orthogonal transform coefficient of a prediction error signal concerning the luminance component and the first and second color difference components and (2) an index indicating 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; a determining module configured to determine either a frame block or a field block for the to-be-decoded block; a deriving module configured to derive the weighting factors and the offsets from the index based on whether the to-be-decoded block is the frame block or the field block; a first generator configured to generate a prediction image for the to-be-decoded block 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; a second generator configured to generate the prediction error signal for the to-be-decoded block by subjecting the quantized orthogonal transform coefficient to inverse quantization and inverse orthogonal transform; and a third generator configured to generate a decoded image signal for the to-be-decoded block by calculating a sum of the prediction error signal and the prediction image; wherein the weighting factors and the offsets which are derived from the index for the field block are identical to the weighting factors and the offsets which are derived from the index for the frame block, the index for the frame block having a value obtained by arithmetic-shifting right by one bit the value of the index for the field block.