Bewegtbildkodierer

摘要

A moving image coder has an arithmetic unit (22) for calculating an average value of a coding object block; an arithmetic unit (23) for obtaining an alternating current component by subtracting the average value from each of pixel values of the coding object block; an arithmetic unit (24) for obtaining a intra frame activity amount by making a calculation of the same kind as an error calculation in a motion prediction with respect to the obtained alternating current component; and a comparator (25) for comparing the intra frame activity amount with a predicting error amount calculated when the motion prediction is made. The inter frame coding mode or the intra frame coding mode is judged by large and small relations of the predicting error amount and the intra frame activity amount. In this moving image coder, codings of a intra frame block and a inter frame differential block are adaptively switched in a small hardware scale. <IMAGE>