MPEG-4: An Object-Based Multimedia Coding Standard Supporting Mobile Applications

The ISO MPEG committee, after successful completion of the MPEG-1 and the MPEG-2 standards is currently working on MPEG-4, the third MPEG standard. Originally, MPEG-4 was conceived to be a standard for coding of limited complexity audio-visual scenes at very low bit-rates; however, in July 1994, its scope was expanded to include coding of scenes as a collection of individual audio-visual objects and enabling a range of advanced functionalities not supported by other standards. One of the key functionalities supported by MPEG-4 is robustness in error prone environments. In general, the MPEG-4 standard provides solutions for coding of natural or synthetic video and audio, as well as a system for multiplex/demultiplex and description of scenes in a truly flexible manner. With focus on the mobile multimedia functionality, we present an overview of the current status as well as the details of the MPEG-4 coding standard. We also discuss profiles, a mechanism used for partitioning MPEG-4 into realizable subsets. Finally, plans for testing and verification of current MPEG-4 (Version 1) standard, ongoing work for MPEG-4 Version 2, as well as directions for MPEG-7, the next MPEG standard, are briefly discussed.