Speech Compression

Text

Material to be covered will be obtained from the following sources

Digital processing of speech signals, L. R. Rabiner and R. W. Schafer.
Linear Prediction of Speech, J.D. Markel and A. H. Gray
IEEE Trans. on Acoustics, Speech and Signal Processing
IEEE Trans. on Speech and Audio

Prerequisite

A basic course in digital signal processing. ECE 251A or ECE 162A is an example of a suggested prerequisite course.

Grade

It is expected that there will be homeworks, a project and a final.

Course Description:

Speech signals, production and perception, Compression theory, High rate compression using waveform coding (PCM, DPCM, ADPCM, ..), DSP tools for low rate coding, LPC vocoders, Sinusoidal transform coding, Multi-Band coding, Medium rate coding using Code Excited Linear Prediction (CELP) .

Course Contents:

Speech Production And Perception: 1-2 Weeks

Speech Production and perception
Characterization of the Speech Signal
Speech Coding Issues

Compression Theory: 1 Week

Entropy and Rate Distortion Theory
Scalar Quantization and Vector Quantization

High Rate Speech Compression - Waveform Coding: 1-2 Weeks

Time Domain Coding

PCM, DPCM, ADPCM, ..

Frequency Domain Coding

Transform and Subband Coding

Digital Signal Processing Tools for Lower Rate Speech Coding: 2-3 Weeks

Spectral Modeling

DFTs and FFTs
Linear Predictive Coding (LPC)

LPC Analysis and Coefficient Quantization Methods

Pitch Extraction

Pitch Estimation and Tracking Methods

Voiced/Unvoiced Detection

Low Rate Speech Compression - Model-based Coding: 1-2 Weeks

Time Domain Coding

LPC Vocoders (LPC-10)

Frequency Domain Coding

Sinusoidal Transform Coding (STC)
Multi-Band Coding (MBE)

Hybrid Approaches

Prototype Waveform Interpolation (PWI)

Medium Rate Speech Compression - Hybrid Coding: 1-2 Weeks

Time Domain Coding - Analysis by Synthesis

Code Excited Linear Prediction (CELP)
The CELP Model
The CELP Pitch Filter/ the Adaptive Codebook
The CELP Codebook
Summary of CELP Standards