This book presents tools and algorithms required to compress/uncompress signals such as speech and music. These algorithms are largely used in mobile phones, DVD players, HDTV sets, etc. In a first rather theoretical part, this book presents the standard tools used in compression systems: scalar and vector quantization, predictive quantization, transform quantization, entropy coding. In particular we show the consistency between these different tools. The second part explains how these tools are used in the latest speech and audio coders. The third part gives Matlab programs simulating these coders.
Introduction xiPART 1. TOOLS FOR SIGNAL COMPRESSION 1Chapter 1. Scalar Quantization 31.1. Introduction 31.2. Optimum scalar quantization 41.3. Predictive scalar quantization 10Chapter 2. Vector Quantization 232.1. Introduction 232.2. Rationale 232.3. Optimum codebook generation 262.4. Optimum quantizer performance 282.5. Using the quantizer 302.6. Gain-shape vector quantization 32Chapter 3. Sub-band Transform Coding 373.1. Introduction 373.2. Equivalence of filter banks and transforms 383.3. Bit allocation 403.4. Optimum transform 463.5. Performance 48Chapter 4. Entropy Coding 534.1. Introduction 534.2. Noiseless coding of discrete, memoryless sources 544.3. Noiseless coding of a discrete source with memory 664.4. Scalar quantizer with entropy constraint 734.5. Capacity of a discrete memoryless channel 794.6. Coding a discrete source with a fidelity criterion 83PART 2. AUDIO SIGNAL APPLICATIONS 89Chapter 5. Introduction to Audio Signals 915.1. Speech signal characteristics 915.2. Characteristics of music signals 925.3. Standards and recommendations 93Chapter 6. Speech Coding 1016.1. PCM and ADPCM coders 1016.2. The 2.4 bit/s LPC-10 coder 1026.3. The CELP coder 107Chapter 7. Audio Coding 1237.1. Principles of “perceptual coders” 1237.2. MPEG-1layer 1 coder 1267.3. MPEG-2AACcoder 1307.4. DolbyAC-3 coder 1347.5. Psychoacoustic model: calculating a masking threshold 135Chapter 8. Audio Coding: Additional Information 1418.1. Low bit rate/acceptable quality coders 1418.2. High bit rate lossless or almost lossless coders 146Chapter 9. Stereo Coding: A Synthetic Presentation 1499.1. Basic hypothesis and notation 1499.2. Determining the inter-channel indices 1519.3. Downmixing procedure 1549.4. At the receiver 1589.5. Draft International Standard 161PART 3. MATLAB_ PROGRAMS 163Chapter 10. A Speech Coder 16510.1. Introduction 16510.2. Script for the calling function 16510.3. Script for called functions 170Chapter 11. A Music Coder 17311.1. Introduction 17311.2. Script for the calling function 17311.3. Script for called functions 176Bibliography 195Index 199