Patent ID: 7492952

Claim:
A picture coding method comprising: generating commands indicating correspondence between reference picture and reference indices designating the reference pictures; determining a maximum value of the reference indices; assigning a reference index to a reference picture, the reference picture being referred to when motion compensation is performed on a current block to be coded; generating a weighting coefficient according to display order information indicating a display order of the input picture; generating a predictive image by performing linear prediction on pixel values of a reference block, using the weighting coefficient, the reference block being obtained by motion estimation between the reference picture and the current block to be coded; generating a prediction error that is a difference between the current block to be coded and the predictive image; and outputting a coded image signal obtained by coding: the reference index assigned to the reference picture in said assigning; information indicating the maximum value of the reference indices; the commands; and the prediction error, wherein the reference index has a first reference index indicating a first reference picture and a second reference index indicating a second reference picture, and said generating of the predictive image includes generating of the predictive image by performing the linear prediction using a predetermined weighting coefficient when the first reference picture designated by the first reference index and the second reference picture designated by the second reference index have identical display order information.