1. A method comprising: selection by a device, for a current image portion to be encoded and for at least one encoding module included in a video encoder, of at least one encoding parameter from amongst a set of encoding parameters available for said at least one encoding module, the selection being based on a decision model defining a minimization, under a rate constraint, of a first measurement of distortion D between source samples, included in said current image portion to be encoded, and current reconstructed samples, included in a current reconstructed image portion, obtained from the current image portion to be encoded; and wherein the decision model defines said minimization under an additional temporal smoothness constraint, pertaining to a second measurement of distortion D′ between said current reconstructed samples and preceding reconstructed samples, belonging to a temporal reference neighborhood comprising at least one preceding reconstructed image portion obtained from at least one preceding encoded image portion, and wherein said additional temporal smoothness constraint, pertaining to the second measurement of distortion D′, is defined by: D′(ŝ N ,ŝ)≦D′ T , with D′ T being a predetermined threshold, ŝ being the current reconstructed samples, and ŝ N being the preceding reconstructed samples.