Abstract: A method and an apparatus are provided for introducing reference impairments into pictures to be used in subjective tests on digital video signals, in compliance with ITU-T Recommendation P.930. The method generates blockiness distortion and/or edge busyness distortion. For the first distortion, areas close to picture edges are selected and, through a movement characteristics analysis, blocks are identified that belong to said areas and that are concerned only by the actual movement of the subject and, for blocks chosen among the identified ones, the luminance value is replaced by a value linked to the individual pixel luminance and to the average block luminance value. For the second distortion, echoes are applied that are randomly chosen in a prearranged set and that alternate at random.