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 video decoding method for decoding encoded data obtained by subjecting a video image having luminance and two color differences to prediction encoding to the video image, comprising:
 receiving an input of encoded data obtained by encoding, for one or more of to-be-decoded blocks, a plurality of combinations comprising (1) a weighting factor for every luminance and two color differences, (2) an offset for every luminance and two color differences and (3) a flag indicating presence or non-presence of the weighting factor and the offset concerning luminance, and encoding, for a to-be-decoded block, (A) a quantized orthogonal transform coefficient, (B) information of motion vectors and (C) a given number of indexes each indicating (a) one combination of the plurality of combinations and (b) a reference image;   deriving the given number of weighting factors and the given number of offsets from the plurality of combinations and the given number of indexes;   generating a prediction image by multiplying the given number of reference images by the weighting factors corresponding to the reference images and adding the given number of the offsets, according to the motion vectors;   generating a prediction error signal by subjecting the quantized orthogonal transform coefficient to inverse quantization and inverse orthogonal transform; and   generating a decoded image signal by calculating a sum of the prediction error signal and the prediction image;   wherein two values of the indexes corresponding to the different reference images respectively indicate an identical combination of the weighting factor and the offset.   
     
     
         2 . A video decoding apparatus of decoding encoded data obtained by subjecting a video image having luminance and two color differences to prediction encoding to the video image, comprising:
 a receiver configured to receive an input of encoded data obtained by encoding, for one or more of to-be-decoded blocks, a plurality of combinations comprising (1) a weighting factor for every luminance and two color differences, (2) an offset for every luminance and two color differences and (3) a flag indicating presence or non-presence of the weighting factor and the offset concerning luminance, and encoding, for a to-be-decoded block, (A) a quantized orthogonal transform coefficient, (B) information of motion vectors and (C) a given number of indexes each indicating (a) one combination of the plurality of combinations and (b) a reference image;   a deriving module configured to derive the given number of weighting factors and the given number of offsets from the plurality of combinations and the given number of indexes;   a first generator configured to generate a prediction image by multiplying the given number of reference images by the weighting factors corresponding to the reference images and adding the given number of the offsets, according to the motion vectors;   a second generator configured to generate a prediction error signal 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 by calculating a sum of the prediction error signal and the prediction image;   wherein two values of the indexes corresponding to the different reference images respectively indicate an identical combination of the weighting factor and the offset.