High-fidelity Multichannel Audio Coding: Pt. 1(EURASIP Book Series on Signal Processing & Communications)

This invaluable monograph addresses the specific needs of audio-engineering students and researchers who are either learning about the topic or using it as a reference book on multichannel audio compression. This book covers a wide range of knowledge on perceptual audio coding, from basic digital signal processing and data compression techniques to advanced audio coding standards and innovate coding tools. It is the only book available on the market that solely focuses on the principles of high-quality audio codec design for multichannel sound sources. This book includes three parts. The first part covers the basic topics on audio compression, such as quantization, entropy coding, psychoacoustic model, and sound quality assessment. The second part of the book highlights the current most prevalent low-bit-rate high-performance audio coding standards - MPEG-4 audio. More space is given to the audio standards that are capable of supporting multichannel signals, that is, MPEG advance audio coding (AAC), including the original MPEG-2 AAC technology, additional MPEG-4 toolsets, and the most recent aacPlus standard. The third part of this book introduces several innovate multichannel audio coding tools, which have been demonstrated to further improve the coding performance and expand the available functionalities of MPEG AAC, and is more suitable for graduate students and researchers in the advanced level. Dai Tracy Yang is currently Postdoctoral Research Fellow, Chris Kyriakakis is Associated Professor, and C.-C. Jay Kuo is Professor, all affiliated with the Integrated Media Systems Center (IMSC) at the University of Southern California.

Table of Contents:
1. Introduction to digital audio 1 1.1. Digital audio coding 1 1.1.1. Representing digital audio signals 1 1.1.2. Building blocks of digital audio codecs 3 1.1.3. Lossy compression and lossless compression 3 1.2. Fundamentals of digital signal processing 4 1.2.1. Fourier transform 4 1.2.2. Sampling operation 5 1.2.3. Sampling theorem and aliasing 7 1.3. Multichannel audio 12 1.3.1. Perceptual cues 13 1.3.2. Surround sound 14 1.3.3. Surround sound standards 15 1.3.4. A future surround sound system 17 1.4. Outline of this book 18 2. Quantization 21 2.1. Scalar quantization 21 2.1.1. Uniform quantization 21 2.1.2. Nonuniform quantization 25 2.2. Vector quantization 26 2.2.1. Nearest-neighbor quantizers 28 2.2.2. Optimality of vector quantizers 29 2.2.3. Vector quantizer design 31 2.3. Bit allocation 32 2.3.1. Problem of bit allocation 33 2.3.2. Optimal bit allocation results 33 3. Entropy coding 35 3.1. Introduction to information theory 35 3.2. Hu.man coding 38 3.2.1. Hu.man coding algorithm 38 3.2.2. Variance of Hu.man codes 39 3.2.3. Hu.man decoding 40 3.2.4. Adaptive Hu.man coding 41 3.3. Arithmetic coding 42 3.3.1. Arithmetic coding algorithm 42 3.3.2. Implementation issues 44 3.3.3. Solving underflow problem 47 3.3.4. Adaptive arithmetic coding 48 3.4. QM coding 51 3.4.1. QM encoder 51 3.4.2. QM decoder 55 3.4.3. Probability estimation 55 4. Introduction to psychoacoustics 59 4.1. Perception of loudness 59 4.2. Masking 61 4.2.1. Frequency masking 62 4.2.2. Temporal masking 63 4.2.3. Interaural masking 64 5. Subjective evaluation of audio codecs 65 5.1. Introduction 65 5.2. Listening environment specifications 65 5.3. Testing methodology 68 5.4. Data analysis after subjective listening tests 69 5.4.1. Mean 69 5.4.2. Variance 69 5.4.3. Standard deviation 71 5.4.4. Standard error of the mean 72 5.4.5. Confidence interval 73 6. MPEG-4 audio coding tools 77 6.1. Introduction to MPEG-4 audio 77 6.2. MPEG-4 audio tools 79 6.2.1. MPEG-4 natural sound coding tools 81 6.2.2. MPEG-4 audio synthesis tools 87 7. MPEG advanced audio coding 91 7.1. Introduction to advanced audio coding 91 7.2. MPEG-2 AAC 92 7.2.1. Overview of MPEG-2 AAC 92 7.2.2. Psychoacoustic model 94 7.2.3. Gain control 94 7.2.4. Transform 95 7.2.5. Spectral processing 98 7.2.6. Quantization 102 7.2.7. Entropy coding 103 7.3. New features in MPEG-4 AAC 105 7.3.1. Perceptual noise substitution 106 7.3.2. Long-term prediction 107 7.3.3. TwinVQ 108 7.3.4. Low-delay AAC 109 7.3.5. Error-resilient tools 111 7.3.6. MPEG-4 scalable audio coding tools 112 7.4. MPEG-4 high-e.ciency AAC 118 7.4.1. Background of SBR technology 119 7.4.2. Basic principle of SBR technology 121 7.4.3. More technical details on high-e.ciency AAC 122 8. Introduction to new audio coding tools 125 8.1. Motivation and overview 125 8.1.1. Redundancy inherent in multichannel audio 125 8.1.2. Quality-scalable single compressed bitstream 126 8.1.3. Embedded multichannel audio bitstream 126 8.1.4. Error-resilient scalable audio bitstream 127 8.2. Audio coding improvements 127 8.2.1. Interchannel redundancy removal approach 128 8.2.2. Audio concealment and channel transmission strategy for heterogeneous network 129 8.2.3. Quantization e.ciency for adaptive Karhunen-Lo`eve transform 129 8.2.4. Progressive syntax-rich multichannel audio codec design 130 8.2.5. Error-resilient scalable audio coding 130 9. Interchannel redundancy removal and channel-scalable decoding 133 9.1. Introduction 133 9.2. Interchannel redundancy removal 133 9.2.1. Karhunen-Lo`eve transform 133 9.2.2. Evidence for interchannel decorrelation 135 9.2.3. Energy compaction e.ect 138 9.2.4. Frequency-domain versus time-domain KLT 141 9.3. Temporal adaptive KLT 143 9.4. Eigen-channel coding and transmission 147 9.4.1. Eigen-channel coding 147 9.4.2. Eigen-channel transmission 149 9.5. Audio concealment for channel-scalable decoding 150 9.6. Compression system overview 152 9.7. Complexity analysis 154 9.8. Experimental results 155 9.8.1. Multichannel audio coding 155 9.8.2. Audio concealment with channel-scalable coding 157 9.8.3. Subjective listening test 160 9.9. Conclusion 162 9.10. Appendix: Karhunen-Lo`eve expansion 163 9.10.1. Definition 163 9.10.2. Features and properties 163 10. Adaptive Karhunen-Lo`eve transform and its quantization e.ciency 165 10.1. Introduction 165 10.2. Vector quantization 166 10.3. E.ciency of KLT decorrelation 167 10.4. Temporal adaptation e.ect 172 10.5. Complexity analysis 176 10.6. Experimental results 176 10.7. Conclusion 177 11. Progressive syntax-rich multichannel audio codec 179 11.1. Introduction 179 11.2. Progressive syntax-rich codec design 180 11.3. Scalable quantization and entropy coding 182 11.3.1. Successive approximation quantization 182 11.3.2. Context-based QM coder 186 11.4. Channel and subband transmission strategy 187 11.4.1. Channel selection rule 187 11.4.2. Subband selection rule 188 11.5. Implementation issues 191 11.5.1. Frame, subband, or channel skipping 191 11.5.2. Determination of the MNR threshold 192 11.6. Complete description of PSMAC codec 192 11.7. Experimental results 193 11.7.1. Results using MNR measurement 194 11.7.2. Subjective listening tests 196 11.8. Conclusions 197 12. Error-resilient scalable audio codec design 199 12.1. Introduction 199 12.2. WCDMA characteristics 201 12.3. Layered coding structure 201 12.3.1. Advantages of the layered coding 201 12.3.2. Main features of scalable codec 202 12.4. Error-resilient codec design 203 12.4.1. Unequal error protection 203 12.4.2. Adaptive segmentation 206 12.4.3. Frequency interleaving 207 12.4.4. Bitstream architecture 209 12.4.5. Error control strategy 209 12.5. Experimental results 210 12.6. Conclusions 213 12.7. Discussion and future work 213 12.7.1. Discussion 213 12.7.2. Future work 214 Bibliography 215 Index 225

About the Author :
Dai Tracy Yang is currently Postdoctoral Research Fellow, Chris Kyriakakis is Associated Professor, and C.-C. Jay Kuo is Professor, all affiliated with the Integrated Media Systems Center (IMSC) at the University of Southern California.

Review :
several innovative multichannel audio coding tools are introduced." --SciTech Book News, Vol.29, No.2, June 2005 "...provides a useful and comprehensive exposition of the principles of some of the mainstream approaches to multichannel audio coding" --J. Audio Eng. Soc., Vol. 53, No. 6, 2005 June IEEE Communications Magazine, September 2005, Vol. 43, No. 9. Reviewer: Prof. Mark Natkaniec "...I recommend it for audio engineers, students, researchers and all others interested in multichannel audio compression" --This text refers to the Hardcover edition. IEEE Signal Processing Magazine, September 2005, Reviewer: Dr. John A. Sorensen "..This book is highly valuable to audio-coding researchers as well as to those seeking background material within this area"