Patent ID: 7372858

Claim:
A data transmission device comprising: an input means for receiving as input a first packet containing header information and real time data, the header information including at least synchronizing time reference information necessary for producing a synchronizing signal to be used by the receiving side; an extraction means for extracting the synchronizing time reference information from the first packet received by said input means; a conversion means for converting the synchronizing time reference information extracted by said extraction means into a time stamp; a packet formation means for forming a second packet containing the header information including the time stamp obtained by the conversion of said conversion means and the first packet received by said input means; and a transmission means for transmitting the second packet formed by said packet formation means wherein said input means receives as input the first packet formatted to the MPEG2-TS format; said extraction means extracts a PCR (Program Clock Reference) contained in the first packet; and said conversion means converts the extracted PCR into the time stamp conforming to the RTP (Real-time Transport Protocol) so as to make it to be contained in the second packet, and wherein a packet identifier (PID) of a transport stream packet containing the PCR is determined (PCR-PID), and said input means determines if the PID of said first packet agrees with the PCR-PID and, if so, said extraction means extracts the PCR of the first packet.