Multimedia Processing in Communications
An Overview: Multimedia Processing
Multimedia has at its very core the field of signal-processing technology. With the exploding growth of the Internet, the field of multimedia processing in communications is becoming more and more exciting. Although multimedia leverages numerous disciplines, signal processing is the most relevant. Some of the basic concepts, such as spectral analysis, sampling theory and partial differential equations, have become the fundamental building blocks for numerous applications and, subsequently, have been applied in such diverse areas as transform coding, display technology and neural networks. The diverse signal-processing algorithms, concepts and applications are interconnected and, in numerous instances, appear in various reincarnated forms.
This chapter is organized as follows. First, we present and analyze digital media and signal processing elements. To address the challenges of multimedia signal processing while providing higher interactivity levels with the media and increased capabilities to access a wide range of applications, multimedia signal-processing methods must allow efficient access to processing and retrieval of multimedia content. Then, we review audio and video coding. During the last decade new digital audio and video applications have emerged for network, wireless, and multimedia computing systems and face such constraints as reduced channel and width, limited storage capacity and low cost. New applications have created a demand for high-quality digital audio and video delivery. In response to this need, considerable research has been devoted to the development of algorithms for perceptually transparent coding of high-fidelity multimedia.
Next, we describe a general framework for image copyright protection through digital watermarking. In particular, we present the main features of an efficient watermarking scheme and discuss robustness issues. The watermarking technique that has been proposed is to hide secret information in the signal so as to discourage unauthorized copying or to attest the origin of the media. Data embedding and watermarking algorithms embed text, binary streams, audio, image or video in a host audio, image or video signal. The embedded data is perceptually inaudible or invisible to maintain the quality of the source data.
We also review the key attributes of neural processing essential to intelligent multimedia processing. The objective is to show why NNs are a core technology for efficient representation for audio-visual information. Also, we will demonstrate how the adaptive NN technology presents a unified solution to a broad spectrum of multimedia applications (image visualization, tracking of moving objects, subject-based retrieval, face-based indexing and browsing and so forth).
Finally, this chapter concludes with a discussion of recent large-scale integration programmable processors designed for multimedia processing, such as real-time compression and decompression of audio and video as well as the next generation of computer graphics. Because the target of these processors is to handle audio and video in real time, the promising capability must be increased compared to that of conventional microprocessors, which were designed to handle mainly texts, figures, tables and photographs. To clarify the advantages of a high-speed multimedia processing capability, we define these chips as multimedia processors. Recent general-purpose microprocessors for workstations and personal computers use special builtin hardware for multimedia processing.
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