PURPOSE: To reduce data amount which is impossible to be decoded when a transmission line is deteriorated and a special reproduction is performed.

CONSTITUTION: The propagation of an error generating on a transmission line is suppressed to an extreme minimum by making the unit of the fixed length of data short by the integral multiple of a sync block by controlling a rearranging circuit 4 by a control signal S3 when data of fixed coding amount is stored within a sync block of a prescribed number as a result of the calculation of the coding amount of data arranged within each sync block in a coding amount estimation circuit 6 (the space from a free area to the free area is made short by rearranging data by dispersedly arranging free areas at the end of each sync block where data of fixed coding amount is written.), and data amount which is impossible to be decoded at the time of the occurrence of an error and at the time of a special reproduction is reduced by increasing a possibility that the data of the same DCT block is arranged at the low-pass part and the high-pass part within the same sync block.