A plurality of object expanding time-lengths, respectively required to expand an object of each rich text medium, are stored in a server for each output format. When a request indicating a particular multimedia title is sent from a reproducing terminal to the server with a particular output format, particular object expanding time-lengths of each particular rich text medium of the particular multimedia title corresponding to the particular output format are read out. In cases where any particular object expanding time-length is not stored in the server, the particular object expanding time-lengths are measured in the server. Thereafter, a medium expanding time-length required to expand one particular rich text medium is calculated from the particular object expanding time-lengths of each particular rich text medium, a scenario indicating a display time of each particular rich text medium and the medium expanding time-lengths are sent to the reproducing terminal. The reproducing terminal sends an expanding request to the server at a specific time earlier than the display time of each particular rich text medium by its medium expanding time-length, so that each particular rich text medium is expanded to a display image in the server, and each display image is displayed at its display time in the reproducing terminal.