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

12The MPEG-2 System Target Decoder Model

The MPEG-2 STD model and differences between the P-STD and the T-STD. Requirements and buffer management for the P-STD; the Constrained System Parameter Program Stream (CSPS). The PES-STD as a special case of the P-STD. Characteristics of the T-STD; the use of transport buffers and other buffers in the T-STD and options for the transfer rates from one buffer to another. General STD constraints and requirements and examples of decoding of audio and video in the STD.

12.1 Introduction to the MPEG-2 STD

The MPEG-2 system target decoder is an essential element of the MPEG-2 system specification, and serves a variety of purposes, as already discussed in Section 6.5. The below bullet points provide a brief summary; for further details see Section 6.5.

• The STD defines the timing of stream delivery and decoding events with mathematical accuracy, based on the instantaneous decoding of access units.
• The STD serves as a mathematical tool to determine compliancy of decoders and streams in an unambiguous manner.
• The STD serves as a hypothetical reference for the design of actual decoders.

In this chapter, the decoding of access units is described in general terms, without addressing for each specific content format all detailed issues on access units, input buffer sizes and the input and output rates of buffers. Therefore in this chapter the decoder of each elementary stream n in the STD is represented by a simple decoder building block D_n, without ...