PURPOSE: To allow the motion compensation predicting unit in the decoding system of a digital motion picture to be in compliance with the H.261 and MPEG and to prevent the circuitry from being increased.

CONSTITUTION: A selector 15 outputs data of a forward direction frame and of a backward direction frame as one data in the case of the MPEG. A lateral direction processing circuit 16 implements the MPEG lateral processing or the H.261 lateral processing. A longitudinal processing circuit 18 implements the MPEG longitudinal processing or the H.261 longitudinal processing. A selector 17 selects a signal of the result of the MPEG lateral processing or a signal of the result of the H.261 lateral processing. A forward backward both-direction processing circuit 19 implements motion compensation prediction in both the forward and backward directions. A selector 20 selects the signal of the result of motion compensation prediction of the MPEG or the signal of the result of motion compensation prediction of the H.261.