Realizing the MPEG-4 multimedia delivery framework

Abstract

MPEG-4 is an emerging international standard based on the encoding of audiovisual data using object description techniques. This novel approach to encoding allows MPEG-4-based multimedia applications to dynamically compose complex scenes from one or more elementary stream objects. These stream objects are carried within potentially hundreds of channels. As a result, the underlying transport system must support the rapid creation and release of such channels with QoS guarantees. In addition to defining the format, structure and rules of composition of these objects, MPEG-4 also specifies a general application and transport delivery framework called the delivery multimedia integration framework (DMIF). DMIF's main purpose is to hide the details of the transport network from the user, as well as to ensure signaling and transport interoperability between end-systems. We describe the first reference implementation of the MPEG-4 DMIF standard for the 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.