Each of a plurality of encoders calculates a first time by adding an encoding delay time commonly determined between the encoders to a value of an STC counter, and transmits a system stream generated by including the calculated first time to a decoder associated with the encoder in one-to-one correspondence, of a plurality of decoders constituting a decoding system. Each of the decoders calculates a second time by adding the first time to an estimated maximum value commonly determined between the decoders by adding a decoding delay time to a value of stream fluctuation of an output time occurring between the encoders, and outputs the divided image data decoded from the system stream to a synthesizer that synthesizes the image data at the calculated second time.