Visual Media Coding and Transmission

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Introduction

Networked Audio-Visual Technologies form the basis for the multimedia communication systems that we currently use. The communication systems that must be supported are diverse, ranging from fixed wired to mobile wireless systems. In order to enable an efficient and cost-effective Networked Audio-Visual System, two major technological areas need to be investigated: first, how to process the content for transmission purposes, which involves various media compression processes; and second, how to transport it over the diverse network technologies that are currently in use or will be deployed in the near future. In this book, therefore, visual data compression schemes are presented first, followed by a description of various media transmission aspects, including various channel models, and content and link adaptation techniques.

Raw digital video signals are very large in size, making it very difficult to transmit or store them. Video compression techniques are therefore essential enabling technologies for digital multimedia applications. Since 1984, a wide range of digital video codecs have been standardized, each of which represents a step forward either in terms of compression efficiency or in functionality. The MPEG-x and H.26x video coding standards adopt a hybrid coding approach, employing block-matching motion estimation/compensation, in addition to the discrete cosine transform (DCT) and quantization. The reasons are: first, a significant proportion of the motion ...