Data transfer apparatus and transfer control method

A control method for a transfer apparatus configured to receive multicast packets of moving image data transmitted via a network and to transfer the multicast packets to receivers connected to the transfer apparatus via a network, the control method including:

• executing control such that one or more of the multicast packets are transferred to at least one receiver in response to a multicast subscribe request received by the transfer apparatus from the at least one receiver;
• storing, in a transmitted and received data buffer, the multicast packets or the one or more of the multicast packets to be transferred to the at least one receiver;
• and
• determining whether transfer of the multicast packet stored in the transmitted and received data buffer can be started when the multicast subscribe request is received from the at least one receiver,
• wherein the multicast packet is transferred in the controlling step based on a determination result of the determining step such that the multicast packet which is to be first transferred to the at least one receiver is a head packet of a frame coded by a first coding technique which does not require information of any other frames when the multicast packet is decoded after the multicast packet has been transferred to the at least one receiver.

A computer-readable storage medium storing a program causing a computer to execute a control method for a transfer apparatus configured to receive multicast packets of moving image data transmitted via a network and to transfer the multicast packets to receivers connected to the transfer apparatus via a network, the program including:

• executing control such that one or more of the multicast packets are transferred to at least one receiver in response in response to a multicast subscribe request received by the transfer apparatus from the at least one receiver;
• storing, in a transmitted and received data buffer, the multicast packets or the one or more of the multicast packets to be transferred to the at least one receiver;
• and
• determining whether transfer of the multicast packet stored in the transmitted and received data buffer can be started when the multicast subscribe request is received from the at least one receiver,
• wherein the multicast packet is transferred in the controlling step based on a determination result of the determining step such that the multicast packet which is to be first transferred to the at least one receiver is a head packet of a frame coded by a first coding technique which does not require information of any other frames when the multicast packet is decoded after the multicast packet has been transferred to the at least one receiver.