3D Visual Communications

5.8 MPEG-4 BIFS and AFX

Standardization of representation formats can facilitate content exchange and encourage the popularity of consumer advanced display devices. An early attempt to standardize 3D representation is conducted by MPEG-4 via binary format for scenes (BIFS) [57]. BIFS is specified as an extension of virtual reality model language (VRML) and inherits all features from VRML. VRML is a text format and defines a set of elements to transmit 3D graphics, including the geometric primitives, 3D meshes, textures, and appearance. The VRML data can be rendered by a VRML player. The interactivity between users and the virtual world, including light sources and collision, is supported. BIFS enriches VRML by providing a better representation, delivery, and rendering for interactive and streamable rich-media services, including 2D and 3D graphics, images, text, and audiovisual material. In place of the text format and the download-and-play of VRML, BIFS adopts binary representation and has a streaming format already adopted in MPEG-4 design. MPEG-4 BIFS extends VRML to include the following new features. First, MPEG-4 BIFS supports integration and management of different audio and video objects seamlessly in a scene. Besides, graphical constructs for 2D and 3D graphics, authoring of complex face and body animation, tools for 3D mesh encoding, and representation of 2D and 3D natural and synthetic sound models are also provided in MPEG-4 BIFS. BIFS enables interactivity between ...