A media processing unit, the media processing unit including: (i) an input interface, configured to receive a second media stream, wherein the second media stream includes first access units and second access units; wherein each second access unit lacks decoding parameters sufficient for full decoding of the second access unit; wherein each first access unit includes decoding parameters required for full decoding of at least one first access unit and of at least one second access unit; (ii) a media-processor, configured to select a selected access unit of the second media stream, and to process the second media stream to provide a processed second media stream by writing into the selected access unit decoding parameters that are responsive to decoding parameters of a previous first access unit; and (iii) a transmitter, configured to transmit the processed second media stream to a splicer.