 have relationships in time and space. It addresses the fact that no single coded representation is ideal for all object types. For instance, animation parameters ideally address a synthetic self-playing piano; an efficient representation of pixel values best suits organic video such as a dancer. MPEG-4 facilitates integration of these different types of data into one scene. MPEG-4 also enables interactivity through hyperlinking with the objects in the scene (e.g., through the Internet). Moreover, MPEG-4 enables selective bit management (pre-determining which bits will be forfeited if bandwidth becomes less than desirable), and straightforward re-use of content without transcoding. Object Type Speech Scalable Synthetic AAC Main AAC SSR AAC LC AAC LTP AAC Scalable TwinVQ Synthetic Wavetable Synthesis General MIDI Algorithmic Synthesis Number of levels Figure Appendix B-6. MPEG-4 Object Types MPEG-4 benefits myriad applications in various environments. Whereas MPEG-2 is constructed as a rigid standard, MPEG-4 represents a set of tools, or profiles that address numerous settings, and countless combinations. MPEG-4 is less an extensive standard than an extensive collection of standards that authors can select and Video Communications: The Whole Picture combine as they choose to improve existing applications or to deploy entirely new ones. It facilitates creation, alteration, adaptation, and access, of audiovisual scenes. With the advent of MPEG-4, one can expect richer virtual environments that will benefit such applications as conventional terrestrial multimedia entertainment, remote multimedia, broadcasting, and even surveillance. MPEG-4 is designed to enable convergence through the coalescence of such different service models as communication, on-line interaction, and communication. To foster competition in the non-normative areas, MPEG-4 specifies normative tools only as interoperability necessitates. For instance, decoding is specified in the standard because it must be normative; video segmentation and rate con