A method and a device for supplying a decoder with data stream such as compressed video signal including both non-predictive and predictive data frames of a common data type. A device comprising a decoder for service data is provided with (1012, 1020) a specific frame that is a predictive frame indicating substantially no changes in the service data in relation to a possible previous service data frame supplied. A service data buffer is monitored (1014) and in case it's at least near an underflow condition according to a number of predetermined criteria (1016), the decoder is fed with the specific frame in order to prevent the decoder from being disturbed due to a lack of timely provided proper input data (1018).