Speech Coding Algorithms: Foundation and Evolution of Standardized Coders

Speech Coding Algorithms : Foundation and Evolution of Standardized Coders......Page 1
CONTENTS......Page 10
PREFACE......Page 16
ACRONYMS......Page 22
NOTATION......Page 26
1 INTRODUCTION......Page 28
1.1 Overview of Speech Coding......Page 29
1.2 Classification of Speech Coders......Page 35
1.3 Speech Production and Modeling......Page 38
1.4 Some Properties of the Human Auditory System......Page 45
1.5 Speech Coding Standards......Page 49
1.6 About Algorithms......Page 53
1.7 Summary and References......Page 58
2.1 Pitch Period Estimation......Page 60
2.2 All-Pole and All-Zero Filters......Page 72
2.3 Convolution......Page 79
Exercises......Page 84
3 STOCHASTIC PROCESSES AND MODELS......Page 88
3.1 Power Spectral Density......Page 89
3.2 Periodogram......Page 94
3.3 Autoregressive Model......Page 96
3.4 Autocorrelation Estimation......Page 100
3.5 Other Signal Models......Page 112
3.6 Summary and References......Page 113
Exercises......Page 114
4 LINEAR PREDICTION......Page 118
4.1 The Problem of Linear Prediction......Page 119
4.2 Linear Prediction Analysis of Nonstationary Signals......Page 123
4.3 Examples of Linear Prediction Analysis of Speech......Page 128
4.4 The Levinson–Durbin Algorithm......Page 134
4.5 The Leroux–Gueguen Algorithm......Page 141
4.6 Long-Term Linear Prediction......Page 147
4.7 Synthesis Filters......Page 154
4.8 Practical Implementation......Page 158
4.9 Moving Average Prediction......Page 164
4.10 Summary and References......Page 165
Exercises......Page 166
5.1 Introduction......Page 170
5.2 Uniform Quantizer......Page 174
5.3 Optimal Quantizer......Page 176
5.4 Quantizer Design Algorithms......Page 178
5.5 Algorithmic Implementation......Page 182
Exercises......Page 185
6.1 Uniform Quantization......Page 188
6.2 Nonuniform Quantization......Page 193
6.3 Differential Pulse Code Modulation......Page 199
6.4 Adaptive Schemes......Page 202
6.5 Summary and References......Page 207
Exercises......Page 208
7 VECTOR QUANTIZATION......Page 211
7.1 Introduction......Page 212
7.2 Optimal Quantizer......Page 215
7.3 Quantizer Design Algorithms......Page 216
7.4 Multistage VQ......Page 221
7.5 Predictive VQ......Page 243
7.6 Other Structured Schemes......Page 246
7.7 Summary and References......Page 248
Exercises......Page 249
8.1 Spectral Distortion......Page 254
8.2 Quantization Based on Reflection Coefficient and Log Area Ratio......Page 259
8.3 Line Spectral Frequency......Page 266
8.4 Quantization Based on Line Spectral Frequency......Page 279
8.5 Interpolation of LPC......Page 283
8.6 Summary and References......Page 285
Exercises......Page 287
9 LINEAR PREDICTION CODING......Page 290
9.1 Speech Production Model......Page 291
9.2 Structure of the Algorithm......Page 295
9.3 Voicing Detector......Page 298
9.4 The FS1015 LPC Coder......Page 302
9.5 Limitations of the LPC Model......Page 304
9.6 Summary and References......Page 307
Exercises......Page 308
10 REGULAR-PULSE EXCITATION CODERS......Page 312
10.1 Multipulse Excitation Model......Page 313
10.2 Regular-Pulse-Excited–Long-Term Prediction......Page 316
10.3 Summary and References......Page 322
Exercises......Page 323
11 CODE-EXCITED LINEAR PREDICTION......Page 326
11.1 The CELP Speech Production Model......Page 327
11.2 The Principle of Analysis-by-Synthesis......Page 328
11.3 Encoding and Decoding......Page 329
11.4 Excitation Codebook Search......Page 335
11.5 Postfilter......Page 344
11.6 Summary and References......Page 352
Exercises......Page 353
12 THE FEDERAL STANDARD VERSION OF CELP......Page 357
12.1 Improving the Long-Term Predictor......Page 358
12.2 The Concept of the Adaptive Codebook......Page 360
12.3 Incorporation of the Adaptive Codebook to the CELP Framework......Page 363
12.4 Stochastic Codebook Structure......Page 365
12.5 Adaptive Codebook Search......Page 368
12.6 Stochastic Codebook Search......Page 371
12.7 Encoder and Decoder......Page 373
12.8 Summary and References......Page 376
Exercises......Page 377
13 VECTOR SUM EXCITED LINEAR PREDICTION......Page 380
13.1 The Core Encoding Structure......Page 381
13.2 Search Strategies for Excitation Codebooks......Page 383
13.3 Excitation Codebook Searches......Page 384
13.4 Gain Related Procedures......Page 389
13.5 Encoder and Decoder......Page 393
13.6 Summary and References......Page 395
Exercises......Page 396
14 LOW-DELAY CELP......Page 399
14.1 Strategies to Achieve Low Delay......Page 400
14.2 Basic Operational Principles......Page 402
14.3 Linear Prediction Analysis......Page 404
14.4 Excitation Codebook Search......Page 407
14.5 Backward Gain Adaptation......Page 412
14.6 Encoder and Decoder......Page 416
14.7 Codebook Training......Page 418
14.8 Summary and References......Page 420
Exercises......Page 421
15.1 Correlation Among the LSFs......Page 423
15.2 Split VQ......Page 426
15.3 Multistage VQ......Page 430
15.4 Predictive VQ......Page 434
15.5 Summary and References......Page 445
Exercises......Page 446
16 ALGEBRAIC CELP......Page 450
16.1 Algebraic Codebook Structure......Page 451
16.2 Adaptive Codebook......Page 452
16.3 Encoding and Decoding......Page 460
16.4 Algebraic Codebook Search......Page 464
16.5 Gain Quantization Using Conjugate VQ......Page 470
16.6 Other ACELP Standards......Page 473
Exercises......Page 478
17 MIXED EXCITATION LINEAR PREDICTION......Page 481
17.1 The MELP Speech Production Model......Page 482
17.2 Fourier Magnitudes......Page 483
17.3 Shaping Filters......Page 491
17.4 Pitch Period and Voicing Strength Estimation......Page 493
17.5 Encoder Operations......Page 501
17.6 Decoder Operations......Page 504
17.7 Summary and References......Page 508
Exercises......Page 509
18 SOURCE-CONTROLLED VARIABLE BIT-RATE CELP......Page 513
18.1 Adaptive Rate Decision......Page 514
18.2 LP Analysis and LSF-Related Operations......Page 521
18.3 Decoding and Encoding......Page 523
18.4 Summary and References......Page 525
Exercises......Page 526
19.1 The Scope of Quality and Measuring Conditions......Page 528
19.2 Objective Quality Measurements for Waveform Coders......Page 529
19.3 Subjective Quality Measures......Page 531
19.4 Improvements on Objective Quality Measures......Page 532
APPENDIX A MINIMUM-PHASE PROPERTY OF THE FORWARD PREDICTION-ERROR FILTER......Page 534
APPENDIX B SOME PROPERTIES OF LINE SPECTRAL FREQUENCY......Page 541
APPENDIX C RESEARCH DIRECTIONS IN SPEECH CODING......Page 545
APPENDIX D LINEAR COMBINER FOR PATTERN CLASSIFICATION......Page 549
APPENDIX E CELP: OPTIMAL LONG-TERM PREDICTOR TO MINIMIZE THE WEIGHTED DIFFERENCE......Page 558
APPENDIX F REVIEW OF LINEAR ALGEBRA: ORTHOGONALITY, BASIS, LINEAR INDEPENDENCE, AND THE GRAM–SCHMIDT ALGORITHM......Page 564
BIBLIOGRAPHY......Page 569
INDEX......Page 580