To characterize film grain, a Film Grain Characterizer (23) receives an incoming information stream (12) and a filtered information stream (24) from which the film grain has been removed. From these streams, the Film Grain Characterizer (23) outputs a message that contains an identity of a model for simulating grain, as well at least one of a set of several parameters, including correlation parameters, intensity-independent parameters and intensity-dependent parameters used by the identified model. An encoder (26, 13) encodes the film grain information for subsequent transmission.