dimensional orthogonal conversion a frequency component considering prediction value calculation unit receives as inputs a pixel value of an encoded adjacent mb and an alternating current frequency component output to create an orthogonal conversion coefficient the orthogonal conversion coefficient then is subjected inverted orthogonal conversion to generate a prediction value p a prediction direction determination unit selects and outputs a prediction value p u2032 in a prediction direction having the highest encoding efficiency among a conventional prediction value calculation unit and a prediction value calculation unit according to the present invention application_number US 5475608 A description the schematic configuration and operation of an encoder to which the present invention is applied will be described as a best embodiment in the description below although the present invention is applied to a reference encoder of h 264 encoding as a video encoder which allows intra intra screen encoding when each mb is encoded the present invention is not limited to this and can be used for a well known jm encoder or jsvm encoder fig1 shows a block diagram of a reference encoder an encode process is largely divided into three processes a prediction value generating process a residual signal encoding process and a local decoding process the prediction value generating process includes an intra prediction unit 1 an inter prediction unit 2 and an encoding efficiency estimation unit 3 the intraprediction unit 1 receives as inputs an input image a and a locally decoded image b of encoded data determines a divided block size and a prediction direction in which encoding efficiency is optimum from candidate prediction directions and outputs a prediction value c and.