Kodiergerät für ein Videosignal

摘要

The coding apparatus for video signal is intended to control a quantizing step width finely depending on the quality of a inputted image. The coding apparatus is designed to obtain an average value of prediction errors at blocks, each block on which the orthogonal transform is carried out and to define the upper limit of a quantizing step width output from the quantizing step width control circuit (330) depending on the average value. It results in making it possible to finely control the quantizing step width particularly based on each part of the image from a background to a dynamic area. <IMAGE>