PURPOSE: To eliminate the difference in picture quality of an encoder and a decoder by eliminating the difference of occupancy rate between the output buffer and the input buffer of each divided systems.

CONSTITUTION: The encoder is provided with encoders A1-A4 compressing divided video signals by the variable quantization bit, output buffers B1-B4 outputting encoder output by constant rate, signal switching device E switching the connection of them for each constant time, and transmitter F sending a switching signal representing the switching contents and sends the buffer output as well as the transmitter output. The decoder is provided with input buffers C1-C4 inputting encoding signals to be separated from the multiplex transmission signal, decoders D1-D4 decoding the input buffer output, signal switching device H switching the connection of them, and receiver G accepting the switching signal to be separated from the multiplex transmission signal and switch- controlling the signal switching device H according to the contents of the signal.