A video data transmission unit transmits data generated by a video data generation unit to an HMD. A sensing data reception unit receives data transmitted from the HMD, the data including size data indicating a size of the data successfully received by the HMD. A required time specification unit specifies time it took for a round-trip communication in half-duplex wireless communication between a relay apparatus and the HMD. A generation control unit controls a size of the data generated by the video data generation unit per unit time based on the specified time, the size indicated in the size data, and a given target time regarding the round-trip communication.