Abstract: A transcoding device includes an interface for receiving a media file in a first format, a transcoder for transcoding the media file to the second format, and output means for outputting the media file in a second format. The interface is preferably suitable for connection to a media file store, such as a PVR, so as to receive and transcode the media file to the second format for output to a portable media player (PMP).

Abstract: Tables of data included in a digital stream of encoded data, e.g. a digital transport stream of a digitally compressed television signal, are modified. The tables of data are extracted from the stream and the extracted tables are processed to identify data that are to be dropped. A filter is used to filter out the identified data and new local data is entered into the extracted tables to replace dropped data and thereby form modified tables of data. The filtered stream is multiplexed with the modified tables of data to form an output digital stream. The constantly updated tables in the input stream are modified only in respect of the local changes and the updates are passed through to the output stream.