In a DVD video playback system adapted to transmit data in the form of a PS (program stream) from a source device to each sink device, a navigation manager of the source device stores system parameters, which are necessary for each sink device to decode the PS, in an unused area of a NV_PACK received from a PS demultiplexer and transmits it to a PS multiplexer. The navigation manager of the source device also produces an ORG_PACK in which navigation data necessary for each sink device to decode the PS, and transmits it to the PS multiplexer. The PS multiplexer produces a PS by multiplexing ORG_PACK and NV_PACK received from the navigation manager, V_PACK received from a video transcoder, and A_PACK and SP_PACK received from the PS demultiplexer, and the PS multiplexer transmits the resultant PS to each sink device via an in-vehicle LAN interface.