In a method to rate a discrete decoded picture (P_in) in respect to its quality a picture quality rating function (PQRF) is calculated on basis of an information about artefacts (ARI) within the discrete decoded picture and a coding information (CRI) which was used for discrete coding the picture. Preferrably, said method is used to determine a preferred discrete picture decoding and/or postprocessing method and/or to determine a preferred discrete picture encoding and/or pre-processing method.