1. A method of encoding a sequence of digital images into a plurality of encoding units forming a bitstream, wherein at least one portion of an image, belonging to a current encoding unit, is encoded by motion compensation with respect to a reference image portion indicated by an item of motion information, comprising selecting a motion information predictor from among a set of motion information predictors and encoding said item of motion information with respect to said motion information predictor, wherein said set of motion information predictors is permitted to include at least one temporal motion information predictor associated with an image portion of a previous image of said sequence but is not permitted to include any spatial motion information predictor that is unobtainable without encoded data of another encoding unit different from said current encoding unit.