Data Structure and Design Considerations

This chapter describes how system time clock (STC) samples and PTS and DTS time stamps are coded. It describes the purpose and specific data structure of the various system descriptors and general content descriptors. The chapter discusses data structure of Moving Picture Experts Group‐2 (MPEG‐2) sections in general and data structure of program association, program map and conditional access sections in particular. It also describes data structure of transport packets, program streams and PES packets. The data structure of the adaptation‐field‐extension starts with the eight‐bit adaptation‐field‐extension‐length, specifying the number of bytes in the adaptation field‐extension. The adaptation‐field‐extension may be concluded by one or more reserved bytes; this is the case if the encoded value of the adaptation‐field‐extension length exceeds the length of the various fields in the adaptation‐field‐extension. The reserved fields can be used by MPEG to extend the functionality of MPEG‐2 systems in future.