Current and future trends in multimedia standards

The ISO MPEG committee, after successful completion of the MPEG-1 and the MPEG-2 standards, is currently working on the next-generation standard called MPEG-4. Originally, MPEG-4 was conceived as a standard for coding limited-complexity audiovisual scenes at very low bit rates. However, in July 1994, its scope was expanded to include the coding of generic audiovisual scenes at low bit rates, while supporting a range of advanced functionalities that are not supported by other standards. Furthermore, the MPEG-4 standard is being designed not only to provide solutions for audio coding, video coding, and systems multiplexing of coded audiovisual data but also to do it in a truly flexible and extensible manner. This part of the chapter provides an overview of the current status of the MPEG-4 standard. First, we briefly describe the ITU-T H.263 standard, which forms the starting basis for the video part of the MPEG-4 standard. We then present the background of MPEG-4 and the requirements it is expected to satisfy. In the following four sections, we discuss the status of the four important parts of the MPEG-4 standard: MPEG-4 Video, MPEG-4 Audio, MPEG-4 Syntax Description Language (MSDL), and MPEG-4 Synthetic and Natural Hybrid Coding (SNHC). Finally, we summarize the current status of MPEG-4 and discuss the direction it is expected to take in the future.