When transmission of on-demand video data interrupts transmission of broadcast video data from a distribution server 17 to a user terminal 18, the distribution server 17 transmits substitute I frame data to the terminal 18 after on-demand video data transmission in complete and before resuming broadcast video data transmission. The user terminal 18 decodes and displays the substitute I frame data, and then uses the decoded substitute I frame data as a reference frame to decode and display the first several frames of broadcast video data received directly after resumption of transmission.