Communication system and method capable of avoiding congestion in moving image data transmission

Abstract

A communication system capable of avoiding congestion in transmission of moving image data, includes (1) at least one receiving terminal, (2) a moving image delivery device for delivering moving image data to the at least one receiving terminal, (3) a moving image conversion device which has at least one moving image conversion unit for converting, in accordance with conversion parameters, the moving image data sent from the moving image delivery device, a conversion parameter setting unit for determining the conversion parameters, and a monitored result receiving unit, and (4) at least one packet switching node which has at least one data storage unit for preliminarily storing the moving image data from the moving image conversion device to be sent to the at least one receiving terminal, a data amount monitor unit for monitoring an amount of the moving image data stored in the at least one data storage unit to judge that the monitored data amount reaches a first threshold, and a monitored result sending unit for sending a congestion preview information to the moving image conversion device when the data amount monitor unit judges that the monitored data amount reaches the first threshold. The monitored result receiving unit receives the congestion preview information from the monitored result sending unit, and the conversion parameter setting unit determines the conversion parameters so that the moving image conversion unit converts the moving image data sent from the moving image delivery device into a moving image data with a smaller coding bit rate.