MPEG-4 3D Graphics: from specifications to the screen Sasko Celakovski*, Marius Preda**, Slobodan Kalajdziski*, Danco Davcev*, Françoise Preteux** *Faculty of Electrical Engineering, Karpos II, bb, 1000 Skopje, Macedonia **ARTEMIS Project Unit, GET-INT, 9, rue Charles Fourier, 91000 Evry, FRANCE etfdav@etf.ukim.edu.mk , marius.preda@int-evry.fr Abstract: - This paper presents a novel implementation of a 3D rendering engine able to display 3D graphics MPEG-4 objects. By using the MPEG-4 SDK (Software Developer Kit), the 3D objects are first decoded and the MPEG-4 scene graph structure is filed. We introduce a scene manager able to address in an optimized manner the rendering requirements. It is developed as part of the rendering engine and it enables to create an appropriate form representation of the data resources. The novel concept implemented here is to consider the scene management with respect to the rendering constraints and not to the representation of the data as in a usual MPEG-4 approach. This paper describes the software communication procedures between the MPEG-4 SDK and the rendering scene management in the case of static and animated (skinned) object and some results dealing with the representation of an articulated model illustrate the performances of the developed approach. Key words -3D Graphics, MPEG-4 Standard, Rendering Engine, Software Developer Kit 1 Introduction The latest developments in the multimedia field as well as the need of exchanging data through a wide spread of networks, lead the scientific and industrial communities to build new and rich multimedia standards. Among existent or on-going multimedia standards, MPEG-4 [1] is one of the most complete in terms of media representation, compression, 2D and 3D graphics primitives, user interaction and programmatic environment. As a member of the MPEG family, the MPEG-4 standard inherits and improves all the features of its predecessors, offering the possibility of efficient transmitting and/or storing a huge amount of digital audio / video. Furthermore, the standard addresses state of the art techniques such as advanced audio coding, video compression-based on visual object, wavelet deployment and mesh-based representation. In addition to representing elementary media, MPEG-4 goes further and specifies mechanisms that allow to create complex multimedia scenes. It is now possible to combine several media, to define synthetic content and to add interaction and dynamic behavior of the scene. These features are supported by using a special description language called BInary Format for Scenes (BIFS). BIFS is based widely on Virtual Reality Modeling Language [2] (VRML) and represents a binary encoded version of an extended subset of VRML, which can represent roughly the same scene as with VRML in a much more efficient manner. In this paper we are interested in the BIFS functionalities for representing synthetic content, especially the 3D objects. The wide range of functionalities supported by MPEG-4 makes this standard one of the most complete and advanced solution, and companies are slowly deploying MPEG-4 technologies inside their applications. The complexity of the standard is a serious drawback and its wide acceptance as a common multimedia format has difficulties to take off. In a previous paper [3], we stated that the development of an MPEG-4 SDK that make transparent for the developer some MPEG-4 key techniques such as encoding, can improve the standard acceptance and speed up the development of applications based on MPEG-4. We demonstrate this statement by developing a 3DSMax plug-in and a Maya exporter. In this paper, we will demonstrate the same concept (facility of building applications based on the MPEG-4 SDK) but in the case of a new application: an MPEG-4 3D player. Currently there is no significant commercial application of MPEG-4 3D capabilities. Some 3D mesh compression implementations of the MPEG-4 3DMC approach are reported in the literature (IBM, Samsung). In addition simple players for face animation provided by face2face inc. [4] or for body animation provided by VRLab [5] and ARTEMIS [6] are only restricted implementations of subparts of MPEG-4 specifications. Any application that would visualize MPEG-4 encoded 3D objects will influence the significance of the whole standard.