JP2570922B

PURPOSE:To obtain the transformation encoder of high compressing efficiency by improving encoding efficiency by executing prescribed processing after constituting a small block group so that the feature of the correlation of picture data becomes similar. CONSTITUTION:The small block group from a picture data block 103 is constituted so that the feature of the correlation of the picture data in each small block 105 becomes similar. One block in this constituted small block group is made a basic small block, and simultaneously, predicted errors 110 from other small blocks are obtained. Next, transformed output 109 for the basic small block and the predicted errors 110 are entropy-coded. Thus, the values of the predicted errors 110 can be concentrated to the vicinity of '0', and simultaneously, encoding can be executed highly efficiently, and the high compression efficiency can be attained.