41 to the second vector comparator 42 shown having a second vector input from vector input line 28 vector comparator 42 determines the vector c 1 or c 2 having the minimum distortion from the vector on line 28 and produces an information bit on line 43 which is applied to the tree pointer conversion circuit 39 so as to identify the pointer tp n which identifies the desired compressed data when the branch selector is not the first branch selector of the chain the output vector on line 29 is passed on to the next branch selector in the pipeline sequence and the pointer on line 29 is coupled to another tree pointer conversion circuit and does not produce the final desired compressed data pointer tp n on line 29 39 as shown with selector 18 for purposes of explaining how data compression is effected by a plurality of identical selectors 18 assume that each pixel shown in source 11 is defined by 8 bits assume further that a cluster of 16 pixels in a 4 u00d7 4 mini array define one input vector to be encoded as each comparison is made in the codebook tree one bit is added to the pointer which identifies or points.