in such portions by a method similar to that of the p code described above another embodiment of the invention will now be described with reference to fig3 fig3 shows a reproducing method according to the invention data reading intervals shown by 31 and 33 are intervals during which a reproducing apparatus reproduces data on a medium a portion indicative of a high speed movement of a data reading position 32 is an interval during which the reproducing apparatus moves the reproducing position of data on the medium for a high speed retrieval after the data reading position has been moved at a high speed upon high speed retrieval the reproducing apparatus retrieves a target position on the medium while repeating the operation to read data according to the invention in such a data reading interval information which has been written in the sub information in the frame signal peculiar to the medium and which indicates whether or not the head of the data for example a picture group of a certain unit of the compressed video data is included in the minimum unit of the data structure peculiar to the medium is judged and on the basis of such information the boundary of data of a certain unit of the compressed.