PURPOSE: To vary a bit rate based on a request from a reception side as always performing coding with a constant method by providing a transmission side from where an orthogonal transform coefficient coded to an arbitrary hierarchy is transmitted to the reception side, and the reception side where an output moving image signal from an inversely quantized orthogonal transform coefficient can be obtained.
CONSTITUTION: At the transmission side, ordinary orthogonal transformation is performed at an orthogonal transform processing part 3, and the coefficient is made into a hierarchy at every single or plural transform coefficients quantized at a quantization part 4 by a hierarchy making part 14, and is coded at a variable length coding part 5. A transmission control part 18 which transmits the orthogonal transform coefficient coded to the arbitrary hierarchy to the reception side replying to the request from the reception side, and a reception control part 19 which couples transmitted code information and transmits the coefficient to a variable complexing part 9 by attaching the code information in accordance with the coefficient representing no change on a part where insufficient transform coefficients exist at the reception side are provided. Therefore, the difference of the contents of frame memory at the transmission side and the reception side can be permitted. In such a way, it is possible to vary the bit rate based on the request from the reception side as always performing constant coding.