MOTION VECTOR CALCULATION METHOD, IMAGE CODING METHOD, IMAGE DECODING METHOD, MOTION VECTOR CALCULATION DEVICE AND IMAGE CODING/DECODING DEVICE

摘要

A motion vector calculation method which attains a higher compression rate, includes: a selection step of selecting one of at least one reference motion vector of a reference block; and a calculation step of calculating a motion vector of a current block to be processed, using the one reference motion vector selected in the selection step, and in the selection step, when the reference block has two reference motion vectors (S121), one of the two reference motion vectors is selected (S123, S124) based on whether the reference block is located before or after the current block in display time order, and when the reference block has only one reference motion vector (S125, S127), the one reference motion vector is selected (S126, S128).