When one-video program data (layer-coded data) of a plurality of layers is transmitted in a single channel, a video signal is layer-coded in an MPEG system, the layer-coded ES (Elementary Stream) data is converted to a PES (Packetized Elementary Stream) for each layer, and the PES is then converted to a RTP (Real-Time Protocol) packet, which is then converted to a UDP (User Datagram Protocol). An identifier is then annexed to a UDP packet data for each layer to form an IP (Internet Protocol) packet.