MPEG-4 is an emerging international standard based on the encoding of audiovisual data usin object description techniques. This novel a proach to encoding allows MPEGdXased multimedia applications to dynamicaiy com ose complex ried within potentially hundreds of channels. As a result, the underlying transport system must support the rapid creation and release of such channels with QoS uarantees. In addition to defining the format, structure and rules of composition of Xese objects, MPEG-4 also specifies a general application and transport delivery framework called the delivery multimedia integration framework. DMIF's main purpose is to hide the details of the transport network from the user, a s well a s to ensure signaling and transport interoperability between end-systems. W e describe the first reference implementation of the MPEG-4 DMIF standard for ISO, including a full specification of the DMIF application interface. The DAI offers the required functionality for realizing multimedia applications without any concerns regarding the selected communication protocol. The realization of DMIF is greatly facilitated by xbind, a broadband kernel that provides connection management, routing, QoS mapping, and intelligent selection of suitable transport protocol stacks. The resulting system, called XDMIF, supports different QoS requirements, and the rapid creation and release of numerous transport channels, along with efficient management of network resources.scenes from one or more elementary stream obiects. These stream o E jects are car-PEG-4 is an emerging international standard that specifies the coding of audio and video data using object description techniques. This novel approach to coding allows multimedia applications to dynamicaily compose complex scenes from one or more elementary streams or synthetic objects. The scene description information, consisting of the logical structure of the scene, spatial and temporal information of the video/audio objects that make up the scene, object attributes, and graphics primitives, is carried within potentially hundreds of data channels. This calls for a high rate of establishment and release of numerous short-term transport channels with the appropriate quality of service (QoS). Traditional methods of signaling are not adequate to meet this demand because of the high overhead introduced. Figure 1 illustrates a typical scenario for information transport between two hosts, including the channels needed for an MPEG-4 scene transfer and composition.The emergence of MPEG-4-based as well as other distributed multimedia applications exhibiting significantly more stringent QoS requirements than conventional data-oriented applications imply the need for transport protocols with different characteristics to coexist and be integrated within single applications. For the first time, application developers have to contend with the fact that a single protocol stack may perhaps be insufficient to meet all their needs. The same developers are also faced with the need to deliver their a...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.