MOVING PICTURE CODING APPARATUS, METHOD THEREFOR, STORING MEDIUM AND MOVING PICTURE DECODING METHOD

摘要

PROBLEM TO BE SOLVED: To keep picture quality of each picture to be uniform in coding a moving image by combining an I picture, a P picture and a B picture. SOLUTION: A time direction change degree calculating section 14 calculates a time direction change degree of a moving image signal on the basis of input image data of a memory 11 and the information of produced code quantity of a buffer 13. A quantization width control section 18 consists of a quantization width coefficient calculating section 15, a GOP quantization width determining section 16, and a picture quantization width determining section 17. The section 18 determines the quantization width of a picture to be coded, by using reference quantization width of the GOP determined on the basis of a prescribed coding rate and the transition of produced code quantity in the buffer 13, and a quantization width coefficient of each picture type calculated from the time direction change degree.