Video coding for mobile communications-MPEG4 perspective

A number of concurrent evolutions have created the need for new ways to represent, integrate, store and exchange pieces of multimedia information. Perhaps the most important is the deployment of diverse new two-way delivery systems such as fixed broadband and mobile narrow-band services. Secondly, the progress of micro-electronic technology is providing extremely powerful and programmable processors, capable of executing very complex algorithms, from the computer vision domain in real time. Finally, there was a marked change in the audiovisual information production and consumption paradigm, because of the increased role of synthetic information and higher degrees of interactivity. In this paper we review some of the new technologies for image and video processing and low-bitrate video coding which are likely, in our view, to be used in future multimedia systems. Whereas some standards, notably H.263 and H.263+ are already used in mobile multimedia communications, new standards, such as MPEG4 and MPEG7 are taking shape. Our review is therefore structured around the objectives and development of MPEG4, and includes the technologies which are likely to be used in the standard. The MPEG-4 project aims to establish universal, efficient coding of different forms of audio-visual and multimedia data, called audio-visual objects. These objects can be of natural or synthetic origin.