The delivery layer in MPEG-4

The MPEG-4 specifications have provided substantial progress in many areas of multimedia technology. Following MPEG tradition, MPEG-4 focuses on media coding. However, a couple of innovative aspects other than media coding characterise MPEG-4 with respect to its predecessors: the ability to code an audio-visual scene, and the ability to abstract from the delivery technology. This paper focuses its attention on this later aspect, which is covered by part 6 of the MPEG-4 specification: DMIF (Delivery Multimedia Integration Framework). The paper explains the motivations that have driven the delivery technology abstraction, analyses the details of the DMIF architecture, and highlights the practical impact on the “bits-on-the-wire” and on conformance issues. It is important not to forget, throughout this paper, that the whole focus of this work is on real-time delivery of multimedia content.