The invention relates to a method of selecting among N “Spatial Video CODECs” where N is an integer number greater than 1, the optimum “Spatial Video CODEC” for a same input signal I. “Spatial Video CODEC” is understood as the combination of any transform of the input signal, followed by a quantization of the transform coefficients and a corresponding entropic coder. Firstly from all the N “Spatial Video CODECs” for the same input signal I and a same quality parameter Q, the rate R and the distortion measures D are obtained. Q is an integer value between 0 and 100, defined by any rate-distortion algorithm to provide a compression of the input sequence with constant rate or with constant distortion. Further an optimality criterion is calculated. The optimality criterion is defined as the minimization of the value Ln=f(Rn,Dn) calculated for all the n from 1 to N. n is the index of the “Spatial Video CODEC”, where f(Rn,Dn) is a function of Rn and Dn. The function f may be defined as as f(Rn,Dn)=Rn+1Dn, , 1 being the Lagrange multiplier that weights the relative influence of the rate R and of the distortion D.