Low-delay vector excitation coding of speech at 8 kbit/s
Jey-Hsin Yao, John J. Shynk, A. Gersho · 2002
A new version of low-delay vector excitation coding (LD-VXC) operating at 8 kb/s that provides very good speech quality is presented. New features of the scheme include an increased vector dimension, closed-loop pitch prediction with fractional pitch values, codebock orthogonalization techniques, and dual-mode interframe coding of the pitch trajectory. Informal listening tests demonstrate that its quality is comparable to that of vector sum excited linear prediction (VSELP) operating at the same rate, while maintaining a delay constraint an order of magnitude smaller than that of VSELP.>