Bandwidth Scalable Wideband Codec Using Hybrid Matching Pursuit Harmonic/CELP Scheme

A novel hybrid harmonic/CELP scheme for bandwidth scalable wideband codec is proposed that utilizes a band-split technique, where the low-band (0-4 kHz) is critically subsampled and coded using 11.8 kbps G.729E. The high-band signal is divided into stationary mode (SM) and non-stationary mode (NSM) components based on its unique characteristics. In the SM portion, the high-band signal is compressed using a multi-stage coding combined sinusoidal model based on the matching pursuit (MP) algorithm and CELP with the circular codebook. In the NSM portion, the high-band signals are coded by CELP with both pulse and circular codebooks. For efficient bit allocation and enhanced performance, the pitch of the high-band codec is estimated using the quantized pitch parameter in low-band codec. In an informal listening test, the subjective speech quality was rated as comparable to that obtainable with 48 kbps G.722 and 12.85 kbps G.722.2.