Image encoding method, image decoding method, image encoding device, image decoding device and program therefor

摘要

Regions based on which an interpolation method of a fractional-accuracy pixel is switched are optimized, and the interpolation method is switched for each of the divided regions, thereby reducing residual energy of inter-frame prediction with motion compensation. A video encoding apparatus is provided with: an encoding information acquiring unit which acquires encoding information for each block; a region classification unit which performs a region classification on a block-by-block basis in accordance with the encoding information; a divided region redefinition processing unit which shifts a region dividing line in a horizontal direction, a region dividing line in a vertical direction, or both the region dividing line in the horizontal direction and the region dividing line in the vertical direction based on a result of the region classification, and determines a region dividing line with which density of blocks belonging to a particular region classification is greater than or equal to a predetermined threshold value; an interpolation method switching unit which switches an interpolation method of a fractional-accuracy pixel for each of divided regions divided by the region dividing line; an interpolation performing unit which performs interpolation of the fractional-accuracy pixel for each of the divided regions; a picture encoding unit which encodes a picture using inter-frame prediction with motion compensation of fractional-accuracy for an interpolated picture; and a region classification information encoding unit which encodes information on the region classification.