APPARATUS AND METHOD FOR UPDATING A PROGRAM MAP TABLE IN A DEMULTIPLEXER

摘要

In an MPEG-2 transmission system a plurality of programs each consisting of a plurality of elementary streams are multiplexed on a transport stream by a multiplexer (8). The transport stream is transmitted by the transmitting means (10) via a transmission medium (16) to a receiver (18). In the receiver (10) the signal is demodulated by the receiving means (12) and demultiplexed by the demultiplexer (14).In order to be able to find the different elementary streams which form a program several tables are used. Said tables which can change over time, are updated by information present in the transport stream. The tables are identified by a version number in order to be able to distinguish different versions of them. The version numbers are not necessarily subsequent numbers. In a prior art transmission system filtering has to be performed on all possible version numbers to find updates of a table.In the transmission system according to the present invention, filtering is performed by only selecting sections having a version number which is different from the previous version numbers.