Data playback apparatus and data relay apparatus

摘要

When a server as a transmission source of content data is changed in a state where the content data from the server are played back in a receiving terminal, the receiving terminal receives the content data starting from the head of its not-yet-played portion to be played. A receiving terminal 100a for receiving content data transmitted from a server to be played is provided with a time information storage processing unit 105a for generating not-yet-played range information Ir indicating a range of a not-yet-played portion in the content data on the basis of time information concerning the playback process, which information is added to the content data in predetermined data units. When receiving a message for requesting to change the server S as the data transmission source, the receiving terminal 100a transmits a message requesting the content data to a new transmission source server with adding the not-yet-played range information to the data.