The conventional quantization control method, in which the buffer memory status is fed back to quantizer, is not the best method for very low bit-rate video applicable to picture communications on the ISDN or the PHS network. This is because it mainly depends on the number of bits previously spent and it causes the picture degradation. In this paper, a new video coding method with spatiotemporal control at pre-processor and adaptive quantization control at coding-engine is proposed. This method enables synthetic control, which consists of estimation of the picture characteristic before encoding and feedback of the number of bits spent by the picture. Details of the synthetic control method and the coding scheme are described, and the performance of this system is discussed.
