Patent ID: 7400652

Claim:
An MPEG-2 decoding system comprising: a transport decoder for decoding a transport packet corresponding to a given PID (Program Identification) in a transport stream inputted thereto from a plurality of transport streams and retrieving a PAT/PMT (Program Association Table/Program Map Table) from said transport stream inputted thereto when it is requested to retrieve PSI (Program Specific Information); a PSI memory for storing PSI; and a pre-decoder directly in communication with said PSI memory and the transport decoder for i) checking the PSI stored in the PSI memory if a request to change to a desired channel is made, ii) reading a PID of a transport packet for an elementary stream of a program corresponding to the desired channel from the PSI memory, iii) providing the read PID) to the transport decoder, iv) receiving the PAT/PMT from the transport decoder at a predetermined time period, and v) updating contents of the PSI memory using the received PAT/PMT; wherein the pre-decoder only receives any of the plurality of transport streams input to the decoding system via the transport decoder.