Audio signal processing and coding

This book splits the difference between a purely academic and a practical approach. It does talk a great deal about the history of various audio representations, and it has some derivations, but it also has some practical numerical examples inserted into the narrative that help explain some of the audio concepts. The exercises at the end of each chapter are on the practical side, stressing numerical problems and MATLAB computer exercises over pure derivations. The book spends the first six chapters going over the basics that you need to know to understand or implement audio coding schemes. Chapter two reviews basic signal processing concepts associated with audio coding. Chapter 3 provides introductory material to waveform quantization and entropy coding schemes. Some of the key topics covered in that chapter include scalar quantization, uniform and nonuniform quantization, pulse code modulation, differential PCM, adaptive DPCM, vector quantization, bit allocation schemes, and entropy coding techniques such as Huffman, Rice, and arithmetic methods. Chapter 4 provides information on linear prediction and its application in narrow and wideband coding. In chapter 5, where psychoacoustic principles are described, Johnston's notion of perceptual entropy is presented as a measure of the fundamental limit of transparent compression for audio. Chapter 6, on filter bank design issues and algorithms, places particular emphasis on the modified discrete cosine transform which is widely used in several perceptual audio coding algorithms. The chapter also addresses pre-echo artifacts and control strategies. Chapters 7,8, and 9 review established and emerging techniques for transparent coding of FM and CD-quality audio signals, including several algorithms that have become international standards. Transform coding methodologies are described in chapter 7, subband algorithms are discussed in chapter 8, and sinusoidal algorithms are presented in chapter 9. Chapter 10 discusses the standardization activities in audio coding. It describes coding standards and products such as the ISO/IEC MPEG family. Details on popular standards, such as the MP3 and MPEG-4 AAC algorithms, are provided. Chapter 11 focuses on lossless audio coding and digital audio watermarking techniques. In particular, the SHORTEN, the DVD algorithm, the MUSICompress, the AudioPaK, and other such coding schemes are described in detail. Chapter 12 provides information on subjective quality measures for perceptual codecs. The five-point absolute and differential subjective quality scales are addressed. A set of subjective benchmarks is provided for the various standards in both stereophonicand multichannel modes so that algorithms can be more easily compared. If you've never been exposed to the subjects discussed in chapters one through six, you'll find this book rough going, since there are entire books written on the subjects that this book is covering in just one chapter each. However, I think it is a good review and a good way for those that are accustomed to looking at these problems from a purely mathematical perspective to see them from the viewpoint of audio processing and coding and to see problems solved using MATLAB. Chapters 7 through 9 are very good at presenting the various algorithms and illustrating them, but the quality seems to drop off as far as details go in the final three chapters starting with the sections on the MPEG standards in chapter 10. This book is good for background and reference, but don't expect to be able to decode or encode anything based solely on what's presented here. AUDIO SIGNAL PROCESSING AND CODING......Page 3 CONTENTS......Page 9 PREFACE......Page 17 1.1 Historical Perspective......Page 23 1.2 A General Perceptual Audio Coding Architecture......Page 26 1.3 Audio Coder Attributes......Page 27 1.3.3 Complexity......Page 28 1.4 Types of Audio Coders – An Overview......Page 29 1.5 Organization of the Book......Page 30 1.6 Notational Conventions......Page 31 Computer Exercises......Page 33 2.2 Spectra of Analog Signals......Page 35 2.3 Review of Convolution and Filtering......Page 38 2.4 Uniform Sampling......Page 39 2.5.1 Transforms for Discrete-Time Signals......Page 42 2.5.2 The Discrete and the Fast Fourier Transform......Page 44 2.5.4 The Short-Time Fourier Transform......Page 45 2.6 Difference Equations and Digital Filters......Page 47 2.7 The Transfer and the Frequency Response Functions......Page 49 2.7.1 Poles, Zeros, and Frequency Response......Page 51 2.7.2 Examples of Digital Filters for Audio Applications......Page 52 2.8.1 Down-sampling by an Integer......Page 55 2.8.2 Up-sampling by an Integer......Page 57 2.8.4 Quadrature Mirror Filter Banks......Page 58 2.9 Discrete-Time Random Signals......Page 61 2.9.1 Random Signals Processed by LTI Digital Filters......Page 64 2.10 Summary......Page 66 Problems......Page 67 Computer Exercises......Page 69 3.1 Introduction......Page 73 3.1.1 The Quantization–Bit Allocation–Entropy Coding Module......Page 74 3.2 Density Functions and Quantization......Page 75 3.3.1 Uniform Quantization......Page 76 3.3.2 Nonuniform Quantization......Page 79 3.3.3 Differential PCM......Page 81 3.4 Vector Quantization......Page 84 3.4.1 Structured VQ......Page 86 3.4.2 Split-VQ......Page 89 3.4.3 Conjugate-Structure VQ......Page 91 3.5 Bit-Allocation Algorithms......Page 92 3.6 Entropy Coding......Page 96 3.6.1 Huffman Coding......Page 99 3.6.2 Rice Coding......Page 103 3.6.3 Golomb Coding......Page 104 3.6.4 Arithmetic Coding......Page 105 Problems......Page 107 Computer Exercises......Page 108 4.1 Introduction......Page 113 4.2 LP-Based Source-System Modeling for Speech......Page 114 4.3 Short-Term Linear Prediction......Page 116 4.3.1 Long-Term Prediction......Page 117 4.4 Open-Loop Analysis-Synthesis Linear Prediction......Page 118 4.5 Analysis-by-Synthesis Linear Prediction......Page 119 4.5.1 Code-Excited Linear Prediction Algorithms......Page 122 4.6.1 Wideband Speech Coding......Page 124 4.6.2 Wideband Audio Coding......Page 126 4.7 Summary......Page 128 Problems......Page 129 Computer Exercises......Page 130 5.1 Introduction......Page 135 5.2 Absolute Threshold of Hearing......Page 136 5.3 Critical Bands......Page 137 5.4 Simultaneous Masking, Masking Asymmetry, and the Spread of Masking......Page 142 5.4.1 Noise-Masking-Tone......Page 145 5.4.4 Asymmetry of Masking......Page 146 5.4.5 The Spread of Masking......Page 147 5.5 Nonsimultaneous Masking......Page 149 5.6 Perceptual Entropy......Page 150 5.7 Example Codec Perceptual Model: ISO/IEC 11172-3 (MPEG - 1) Psychoacoustic Model 1......Page 152 5.7.2 Step 2: Identification of Tonal and Noise Maskers......Page 153 5.7.3 Step 3: Decimation and Reorganization of Maskers......Page 157 5.7.4 Step 4: Calculation of Individual Masking Thresholds......Page 158 5.8 Perceptual Bit Allocation......Page 160 Problems......Page 162 Computer Exercises......Page 163 6.1 Introduction......Page 167 6.2 Analysis-Synthesis Framework for M-band Filter Banks......Page 168 6.3 Filter Banks for Audio Coding: Design Considerations......Page 170 6.3.2 The Role of Frequency Resolution in Perceptual Bit Allocation......Page 171 6.3.3 The Role of Time Resolution in Perceptual Bit Allocation......Page 172 6.4 Quadrature Mirror and Conjugate Quadrature Filters......Page 177 6.5 Tree-Structured QMF and CQF M-band Banks......Page 178 6.6 Cosine Modulated “Pseudo QMF” M-band Banks......Page 182 6.7 Cosine Modulated Perfect Reconstruction (PR) M-band Banks and the Modified Discrete Cosine Transform (MDCT)......Page 185 6.7.2 MDCT Window Design......Page 187 6.7.3 Example MDCT Windows (Prototype FIR Filters)......Page 189 6.8 Discrete Fourier and Discrete Cosine Transform......Page 200 6.9 Pre-echo Distortion......Page 202 6.10.2 Window Switching......Page 204 6.10.3 Hybrid, Switched Filter Banks......Page 206 6.10.5 Temporal Noise Shaping......Page 207 6.11 Summary......Page 208 Problems......Page 210 Computer Exercises......Page 213 7.1 Introduction......Page 217 7.2 Optimum Coding in the Frequency Domain......Page 218 7.3 Perceptual Transform Coder......Page 219 7.3.1 PXFM......Page 220 7.3.2 SEPXFM......Page 221 7.4 Brandenburg-Johnston Hybrid Coder......Page 222 7.5.2 CNET MDCT Coder 1......Page 223 7.5.3 CNET MDCT Coder 2......Page 224 7.6 Adaptive Spectral Entropy Coding......Page 225 7.7 Differential Perceptual Audio Coder......Page 226 7.8 DFT Noise Substitution......Page 227 7.9 DCT with Vector Quantization......Page 228 7.10 MDCT with Vector Quantization......Page 229 Problems......Page 230 Computer Exercises......Page 232 8.1 Introduction......Page 233 8.1.1 Subband Algorithms......Page 234 8.2 DWT and Discrete Wavelet Packet Transform (DWPT)......Page 236 8.3.1 DWPT Coder with Globally Adapted Daubechies Analysis Wavelet......Page 240 8.3.2 Scalable DWPT Coder with Adaptive Tree Structure......Page 242 8.3.4 DWPT Coder with Adaptive Tree Structure and Locally Adapted Analysis Wavelet......Page 245 8.3.5 DWPT Coder with Perceptually Optimized Synthesis Wavelets......Page 246 8.4.1 Switched Nonuniform Filter Bank Cascade......Page 248 8.5 Hybrid WP and Adapted WP/Sinusoidal Algorithms......Page 249 8.5.1 Hybrid Sinusoidal/Classical DWPT Coder......Page 250 8.5.2 Hybrid Sinusoidal/M-band DWPT Coder......Page 251 8.5.3 Hybrid Sinusoidal/DWPT Coder with WP Tree Structure Adaptation (ARCO)......Page 252 8.6 Subband Coding with Hybrid Filter Bank/CELP Algorithms......Page 255 8.6.1 Hybrid Subband/CELP Algorithm for Low-Delay Applications......Page 256 8.6.2 Hybrid Subband/CELP Algorithm for Low-Complexity Applications......Page 257 Problems......Page 259 Computer Exercise......Page 262 9.1 Introduction......Page 263 9.2.1 Sinusoidal Analysis and Parameter Tracking......Page 264 9.2.2 Sinusoidal Synthesis and Parameter Interpolation......Page 267 9.3 Analysis/Synthesis Audio Codec (ASAC)......Page 269 9.3.3 ASAC Bit Allocation, Quantization, Encoding, and Scalability......Page 270 9.4 Harmonic and Individual Lines Plus Noise Coder (HILN)......Page 271 9.4.1 HILN Sinusoidal Analysis-by-Synthesis......Page 272 9.5 FM Synthesis......Page 273 9.5.2 Perceptual Audio Coding Using an FM Synthesis Model......Page 274 9.6 The Sines + Transients + Noise (STN) Model......Page 276 9.7 Hybrid Sinusoidal Coders......Page 277 9.7.1 Hybrid Sinusoidal-MDCT Algorithm......Page 278 9.7.2 Hybrid Sinusoidal-Vocoder Algorithm......Page 279 Problems......Page 280 Computer Exercises......Page 281 10.1 Introduction......Page 285 10.2.1 MIDI Synthesizer......Page 286 10.2.3 MIDI Applications......Page 288 10.3.1 The Evolution of Surround Sound......Page 289 10.3.3 The ITU-R BS.775 5.1-Channel Configuration......Page 290 10.4 MPEG Audio Standards......Page 292 10.4.1 MPEG-1 Audio (ISO/IEC 11172-3)......Page 297 10.4.2 MPEG-2 BC/LSF (ISO/IEC-13818-3)......Page 301 10.4.3 MPEG-2 NBC/AAC (ISO/IEC-13818-7)......Page 305 10.4.4 MPEG-4 Audio (ISO/IEC 14496-3)......Page 311 10.4.5 MPEG-7 Audio (ISO/IEC 15938-4)......Page 331 10.4.6 MPEG-21 Framework (ISO/IEC-21000)......Page 339 10.5 Adaptive Transform Acoustic Coding (ATRAC)......Page 341 10.6.1 Perceptual Audio Coder (PAC)......Page 343 10.6.3 Multichannel PAC (MPAC)......Page 345 10.7.1 Dolby AC-2, AC-2A......Page 347 10.7.2 Dolby AC-3/Dolby Digital/Dolby SR · D......Page 349 10.8 Audio Processing Technology APT-x100......Page 357 10.9.1 Framing and Subband Analysis......Page 360 10.9.3 ADPCM – Differential Subband Coding......Page 361 10.9.4 Bit Allocation, Quantization, and Multiplexing......Page 363 Computer Exercise......Page 364 11.1 Introduction......Page 365 11.2 Lossless Audio Coding (L(2)AC)......Page 366 11.2.1 L(2)AC Principles......Page 367 11.2.2 L(2)AC Algorithms......Page 368 11.3 DVD-Audio......Page 378 11.4 Super-Audio CD (SACD)......Page 380 11.4.2 Sigma-Delta Modulators (SDM)......Page 384 11.4.3 Direct Stream Digital (DSD) Encoding......Page 386 11.5 Digital Audio Watermarking......Page 390 11.5.1 Background......Page 392 11.5.2 A Generic Architecture for DAW......Page 396 11.5.3 DAW Schemes – Attributes......Page 399 11.6 Summary of Commercial Applications......Page 400 Computer Exercise......Page 404 12.1 Introduction......Page 405 12.2 Subjective Quality Measures......Page 406 12.3 Confounding Factors in Subjective Evaluations......Page 408 12.4 Subjective Evaluations of Two-Channel Standardized Codecs......Page 409 12.5 Subjective Evaluations of 5.1-Channel Standardized Codecs......Page 410 12.6 Subjective Evaluations Using Perceptual Measurement Systems......Page 411 12.6.2 NSE Perceptual Measurement Schemes......Page 412 12.7 Algorithms for Perceptual Measurement......Page 413 12.7.1 Example: Perceptual Audio Quality Measure (PAQM)......Page 414 12.7.2 Example: Noise-to-Mask Ratio (NMR)......Page 418 12.7.3 Example: Objective Audio Signal Evaluation (OASE)......Page 421 12.8 ITU-R BS.1387 and ITU-T P.861: Standards for Perceptual Quality Measurement......Page 423 12.9 Research Directions for Perceptual Codec Quality Measures......Page 424 REFERENCES......Page 427 INDEX......Page 481 Master algorithms and standards for transparent coding of high-fidelity audio Here is an in-depth treatment of algorithms and standards for transparent coding of high-fidelity audio. Readers learn how algorithms for high-quality digital audio deliver transparent signal reproduction with a minimum number of bits. The unique features of the book include detailed coverage of topics such as filter banks, transform coding, sinusoidal analysis, linear prediction, hybrid algorithms, perceptual evaluation methods, scalable algorithms, Internet applications, MP3 and MP4 stereo systems, and current international and commercial audio standards. Following a general introduction, the authors present fundamental signal processing concepts relevant to audio coding and then introduce waveform and entropy quantization schemes. Next are thorough treatments of the following topics: . Linear prediction, ADPCM, and CELP algorithms for narrowband and wideband coding. Cellular telephony vocoders versus CD-quality audio coders. Perceptual modules including the ISO/IEC 11172-3 (MPEG-1) psychoacoustic analysis model. Detailed descriptions of the MPEG-1 Layer III (MP3) and the AAC (MP4) algorithms. Descriptions of the algorithms behind successful products such as the Apple iPod. Filter bank design and algorithms and the Modified Discrete Cosine Transform (MDCT). Established and emerging standards for transparent coding of CD-quality stereo audio signals. Standardization activities in high-fidelity audio coding, including DVD-Audio, Super Audio CD (SACD), Dolby AC3, Digital, Digital Theater Systems (DTS), and Sony SDDS surround sound. Lossless audio coding and digital audio watermarking techniques, including SHORTEN, DVD-algorithm, MUSICompress, AudioPaK, C-LPAC, LTAC, and IntMDCT lossless coding schemes. Surround sound compression algorithms for cinema and super audio CD applications. Digital audio watermarking, content protection, and copyright issues. Complexity, delay, error control, and subjective quality in perceptual audio coding Computer exercises and MATLAB(R) hands-on projects complement the algorithm theory and reinforce concept learning. A comprehensive bibliography with more than 600 references to additional sources of information to explore individual topics in greater depth. This textbook includes all the right elements and topics for a senior and/or graduate-level course in speech/audio processing and multimedia. Moreover, it is highly recommended for practitioners, scientists, and audio engineers who want to master coding algorithms for high-fidelity audio An in-depth treatment of algorithms and standards for perceptual coding of high-fidelity audio, this self-contained reference surveys and addresses all aspects of the field. Coverage includes signal processing and perceptual (psychoacoustic) fundamentals, details on relevant research and signal models, details on standardization and applications, and details on performance measures and perceptual measurement systems. It includes a comprehensive bibliography with over 600 references, computer exercises, and MATLAB-based projects for use in EE multimedia, computer science, and DSP courses. An ftp site containing supplementary material such as wave files, MATLAB programs and workspaces for the students to solve some of the numerical problems and computer exercises in the book can be found at ftp://ftp.wiley.com/public/sci_tech_med/audio_signal Signal Processing Essentials -- Quantization And Entropy Coding -- Linear Prediction In Narrownband And Wideband Coding -- Psychoacoustic Principles -- Time-frequency Analysis: Filter Banks And Transforms -- Transform Coders -- Subband Coders -- Sinusoidal Coders -- Audio Coding Standards And Algorithms -- Lossless Audio Coding And Digital Watermarking -- Quality Measures For Perceptual Audio Coding. Andreas Spanias, Ted Painter, Venkatraman Atti. Includes Bibliographical References And Index.