JP2905490B

PURPOSE:To change a maximum number of pictures, which can be stored in a memory, without degrading the picture quality of a restored picture by subtracting forecast data from data obtained by A/D conversion of an analog video signal and compressing the subtraction result and forming forecast data with upper bits of compressed data. CONSTITUTION:A forecast value outputted from a local decoder 203 is subtracted from digital data of an inputted Y signal by a subtractor 201. This subtraction result is outputted as compressed output data (z) from a linear or nonlinear quantizer 202. Upper three bits of this compressed data are inputted to a representative value setter 206 in the local decoder 203, and the forecast value and a representative value outputted from the representative value setter 206 are added by an adder to obtain the forecast value for digital data of the Y signal, and it is supplied to a subtractor 201. Thus, a maximum number of pictures which can be stored in the memory is changed without conspicuous degradation of the picture quality of the restored picture.