adds it to the output of the motion compensator 11 this produces a signal corresponding to the original image signal the output of the motion compensator 50 is applied to the adders 8 a 8 b by refresh switches rsw 2 and rsw 1 respectively the quantized image signal is also supplied to a multi scanner 80 which scans it according to a plurality of predetermined patterns a scanner pattern selector 90 selects the scanning pattern which produces the minimum number of bits to represent the current sub block the scanning pattern selector also produces selection data which identifies the selected scanning pattern the image signal output by the scanning pattern selector 90 is variable length coded by a variable length coder 60 the variable length coder 60 compresses the image signal output by the scanning pattern selector 90 the variable length coder 60 operates such that a large proportion of the data samples are each represented by a small number of bits while a small proportion of the data samples are each represented by a large number of bits when a discrete cosine transformed image signal is quantized and runlength coded the number of u201c 0 u201d s is increased over all while the number of u201c 0 u201d s decreases as the magnitude of the signal increases accordingly data compression is achieved because u201c 0 u201d can be represented by only a few bits and u201c 255 u201d can be represented by a relatively large.