| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve transmission efficiency in transmitting video data through a plurality of kinds of transmission lines with different transmission rates. <P>SOLUTION: A control part 13 of an intercom master unit 1, for example, multicasts I frames FI1, FI2, ..., and first P frames FP11, FP21, ..., with respect to addresses of all intercom secondary master units 2A, 2B and 2C being transmission destinations of video data, unicasts all of the remaining P frames FP12 to FP15 and FP22 to FP25, ..., with respect to the intercom secondary master unit 2A, unicasts only a portion of the remaining P frames FP12 to FP15 and FP22 to FP25, ..., with respect to the intercom secondary master unit 2B, and does not transmit any of the remaining P frames FP12, ..., to the radio intercom secondary master unit 2C. An appropriate data amount of video data corresponding to the respective transmission lines Ls therefore can be transmitted, so that the transmission efficiency can be improved. <P>COPYRIGHT: (C)2009,JPO&INPIT |
