SPEECH COMPRESSION USING WAVELET TRANSFORM

Abstract

The field of Speech Compression deals with digital signal processing techniques that focuses on reducing bit-rate of speech signals to enhance transmission speed and to reduce the storage requirement of fast developing multimedia age. Speech compression techniques are utilized to reduce the number of bits required to represent speech signals (by reducing redundancy) in order to minimize the requirement for transmission bandwidth (e.g.. for voice transmission over mobile channels with limited capacity) or to reduce the storage costs (e.g., for speech recording). This report explores a transform based methodology for compression of the speech signal. Different transforms methods exploited involve Discrete Wavelet Transform (DWT). Fast Fourier Transform (FFT) and I)iscrete ('osinc Transform (DCT). Work done here iiiainl focuses on compression using DWT. A comparative study of performance of various wavelets is made in terms of Signal to noise ratio (SNR). Compression ratio (CR). Peak signal to noise ratio (PSNR). Retained signal energy (RSEi) and Normalized root-mean square error (NRMSE). Run Length Encoding(RLE) technique has been used for encoding wavelet coefficients. Matlab code is writlen and simulated for compressing the male and female speech samples.