IMAGE ENCODING METHOD AND IMAGE ENCODING DEVICE

摘要

The present invention, which reduces buffer delay while minimizing image-quality degradation, performs low-delay video encoding. This image encoding method is provided with the following steps: a quantization step in which inputted information is quantized on the basis of the value of a quantization parameter, thereby reducing the size of said information; an entropy-encoding step in which the output of the quantization step is subjected to an entropy-encoding process and the resulting encoded information is outputted along with information on the size of said encoded information; and a rate-control step in which the value of the quantization parameter is determined on the basis of the size of the aforementioned encoded information. In the rate-control step, for each block, said blocks being smaller than frames, the value of the quantization parameter is increased if the bit allocation within said block is predicted to exceed a prescribed value but decreased if the bit allocation within said block is predicted to be less than said prescribed value.