an area to transmit or record the sub information which is different from an area to transmit or record main information in the frame signal peculiar to the medium another embodiment of the invention will now be described with reference to fig2 the embodiment relates to a case where the invention is applied to a compact disc cd a cd rom or a system having a data structure and a frame format which are equivalent to those of the cd rom in fig2 reference numeral 20 denotes time sequential data of a pack a boundary between b and c indicates a boundary of a group of pictures a head of the c portion denotes a head of data of the picture group reference numeral 21 denotes a data structure which is peculiar to the medium a a header section including a sync signal or the like b and c data to which the time sequential data of the pack is divided and is allocated and which is equivalent to the b and c portions of the time sequential data of the pack and d other data including a margin section such a b c and d portions indicate minimum units of the.