A multimedia information processing system comprises an information-source coding section for generating an element packet containing coded multimedia information and additional information to specify the packet, a packet multiplexing section for generating multiplexed stream by multiplexing the element packet, and a transmission processing section for outputting the multiplexed stream as a transmission signal corresponding transmission media. In this multimedia information processing system, a processing sequence from selection of multimedia information to transmission or storage processing is classified, and the processing contents and input/output data are determined for each hierarchy. Data exchange between services such as broadcasting, communication, storage in computer and so on can be easily attained. Additionally, hardware structure of this system can be simplified, and additional functions can be easily added.