VARIABLE RATE PICTURE GRADATION CODING SYSTEM

摘要

PURPOSE:To improve picture quality by providing a threshold level to an in- block power when a moving picture signal subjected to orthogonal conversion is subjected to gradation, comparing the in-block power with the threshold level and varying (in-block code quantity assigned to MSP in-block total code quantity) adaptively. CONSTITUTION:In the case of gradation, at first an in-block power measuring device 403 and an in-block total code quantity measuring circuit 404 calculate in-block power (p) of each block and in-block total code quantity (c). Then the in-block power (p) is compared with two in-block power threshold values pth1, pth2 (pth1