Abstract

A system of coding moving image signals produces a predictive error signal by a predictive coding based on inter-frame correlation and quantizing the predictive error signal for each block of a picture frame constituted by N lines of M pixels. The system includes a block coding/non-coding decision unit for calculating a first evaluation value Sm of the predictive error signal for each block of the picture frame. This unit decides that block non-coding is applicable when the first evaluation value Sm is less than a first threshold value T1 and that block coding is applicable when the first evaluation value Sm is greater than the first threshold value T1. The predictive error signal is not transmitted when the result of the decision is for block non-coding, and the predictive error signal is quantized and transmitted when the result of the decision is for block coding.