On the performance of wavelets for low bit rate coding of audio signals

The performance of some different wavelet families, including for comparison a well known family of QMFs, is investigated for low bit rate coding of audio signals. For the assessment of the coding gain of these wavelets, both octave and uniform subband coding schemes have been evaluated, using both constant and dynamic bit allocation, with and without entropy noiseless Huffman coding. The influence of complexity of these wavelets, in terms of number of filter coefficients, against the quality of the decompressed audio signals in terms of segmental-SNR (dB), is presented, at different bit rates. In addition, this evaluation suggests that perceptually transparent quality of monophonic signals can be achieved at 24 kbits/sec (Fs=8 kHz, 3 bits/sample) for speech applications and at 64 kbits/sec (Fs=48 kHz, 1.33 bits/sample) for music related applications, as in digital audio transmission and storage