Harmonic vector excitation coding of speech at 2.0 kbps
L. Nishiguchi, K. Iijima, J. Matsumoto · 2002
A low rate speech coding algorithm, harmonic vector excitation coding (HVXC) is proposed for MPEG-4 standardization, in which an efficient coding scheme based on harmonic and stochastic vector representation of linear predictive coding (LPC) residuals is employed. A combination of weighted vector quantization of harmonic spectral envelope of LPC residual signal for voiced segments and vector excitation coding for unvoiced segments provides good speech duality at very low bit rates. MPEG-4 formal listening tests in December 95 showed that the subjective speech quality of HVXC at 2.0 kbps was better than that of FS1016 4.8 kbps CELP.