A method of a transmission device in a multimedia system comprises the steps of: detecting a request for changing first-type data into second-type data while the first-type data is being played at a given point in time; and transmitting, before the second-type data is played, information necessary for replaying data, among the first-type data, played prior to the given point in time, and/or data, among the second-type data, played prior to the given point in time.