Fundamentals and Evolution of MPEG-2 Systems: Paving the MPEG Road

9Layering in MPEG-2 Systems

Distinction of program streams and transport streams within MPEG-2 systems and PES packets as a common layer to carry content in both. Forming a program stream from PES packets. The structure of a transport stream and the use of transport packets. Navigation information on multiple programs and streams in a transport stream. Carriage of PES packets in transport packets. Consideration on the size of a transport packet. The use of sections for carrying information in a transport stream, and how to convey sections in transport packets.

9.1 Need for Program Streams and Transport Streams

MPEG-2 systems is build on top of MPEG-1 systems and supports the same basic functionality. This includes packetization and multiplexing of multiple video, audio or other elementary streams into a single system stream, synchronization of video and audio, buffer management and timing control. Also, the concept of a System Target Decoder model is used in MPEG-2 systems. As a result, MPEG-2 systems has a high level of commonality with MPEG-1 systems, but to properly address the various requirements on MPEG-2 systems, it did not prove practical to define MPEG-2 systems as a fully compatible extension of MPEG-1 systems.

The main reason why MPEG-2 systems is not fully compatible with MPEG-1 systems is found in the error prone networks used for digital television broadcast, such as satellite, cable and terrestrial. While those networks typically have a high bandwidth allowing ...