Method and system for time synchronized forwarding of ancillary information in stream processed MPEG-2 systems streams

摘要

A method and system are provided for processing an elementary stream in a systems layer stream that is presumed to be ultimately consumed according a to predefined and deterministic schedule relative to a particular system time clock of a program that comprises the elementary stream. First and second synchronization points are identified in an elementary stream. The elementary stream is processed to produce a modified sequence of elementary stream information to be carried between the first and second synchronization points. The modified sequence has a different amount of information than the particular sequence of information. A series of one or more new systems layer stream segments carrying the first synchronization point, as well as the modified sequence of elementary stream information, are inserted into a new systems layer stream. At least one of the new systems layer stream segments comprises a systems layer information sub-segment containing the particular ancillary data. Each synchronization point is a type of sequential location of the elementary stream: (1) which recurs continually throughout the elementary stream; (2) is synchronized in time to the systems time clock of the program containing the elementary stream; and (3) is always present in an elementary stream both prior to, and after, the processing.