Video encoding/decoding method and apparatus

Abstract

A video encoding method comprises selecting one combination, for each block of an input video signal, from a plurality of combinations each including a predictive parameter and at least one reference picture number determined in advance for the reference picture, generating a prediction picture signal in accordance with the reference picture number and predictive parameter of the selected combination, generating a predictive error signal representing an error between the input video signal and the prediction picture signal, and encoding the predictive error signal, information of the motion vector, and index information indicating the selected combination.

1 . A prediction image generating method for generating a prediction image from encoded data obtained by subjecting a video image having luminance and two color differences to prediction encoding, comprising:
 receiving an input of encoded data obtained by encoding, for a to-be-decoded block, a given number of indexes, each of the indexes indicating (A) a reference image and (B) a combination comprising (a) a weighting factor every luminance and two color differences and (b) an offset every luminance and two color differences;   deriving the given number of weighting factors and the given number of offsets from the given number of indexes; and   generating a prediction image by multiplying the given number of reference images by the weighting factors corresponding to the respective reference images and adding the given number of offsets,   wherein two values of the index which correspond to the different reference images respectively indicate an identical combination of the weighting factor and the offset.   
     
     
         2 . A prediction image generating apparatus of generating a prediction image from encoded data obtained by subjecting a video image having luminance and two color differences to prediction encoding, comprising:
 a receiver configured to receive an input of encoded data obtained by encoding, for a to-be-decoded block, a given number of indexes, each of the indexes indicating (A) a reference image and (B) a combination comprising (a) a weighting factor every luminance and two color differences and (b) an offset every luminance and two color differences;   a deriving module configured to derive the given number of weighting factors and the given number of offsets from the given number of indexes; and   a generator configured to generate a prediction image by multiplying the given number of reference images by the weighting factors corresponding to the respective reference images and adding the given number of offsets,   wherein two values of the index which correspond to the different reference images respectively indicate an identical combination of the weighting factor and the offset.