TABLE OF CONTENTS This chapter contains an overview of the MPEG-2 standard. The MPEG-2 system syntax is reviewed in Section 9.4. Scalable MPEG-2 features are discussed briefly in Section 9.8. Chapter 10 provides more details of the MPEG-2 video main profile syntax. [1]
Readers should be aware that MPEG-2 is a large, complex standard. The descriptions we provide here and in the next chapter are only an introduction to this important standard.
MPEG-2 offers little benefit over MPEG-1 for programming material that was initially recorded on film. In fact, nearly all movies and television programs with high production values (budgets) are shot at 24 celluloid frames per second. What MPEG-2 does offer is a more efficient means to code interlaced video signals, such as those that originate from electronic cameras (vacuum tubes or CCDs). MPEG-1 was frozen in 1991, and was intended only for progressive (i.e., noninterlaced) video pictures. MPEG-2 was initiated that same year with the goal of defining a syntax suitable for interlaced video. MPEG-2 video syntax was frozen in April 1993; in 1995, two years later, the three primary documents (systems, video, audio) which comprise the MPEG-2 standard finally reached international standard status.
Although MPEG-2 encoders may be focused on interlaced video coding, they often possess more mature and powerful coding methods that can also be applied to create better MPEG-1 bitstreams. Indeed, MPEG-2 encoders need to be at least 50% more powerful than an MPEG-1 encoder capable of processing the same sample rate.
