1. A data processing apparatus outputting picture data to a reproduction apparatus reproducing a plurality of picture data in an order in accordance with a designated reproduction direction, the data processing apparatus comprising a processing circuit outputting to said reproduction apparatus said picture data in an order in accordance with a reproduction direction designated in said reproduction apparatus and writing it into an input memory in said reproduction apparatus and, when reversing said reproduction direction designated at said reproduction apparatus, outputting said picture data to said reproduction apparatus conditional on said picture data to be used next in reproduction by said reproduction direction after reversal not being stored in said input memory.