A 450bps Speech Coding Algorithm Based on Multi-Mode Matrix Quantization

A 450 bps speech coder based on multi-frame structure and multi-mode matrix quantization is presented. The multiframe structure consisting of four frames is adopted to reduce the algorithm delay. The parameter matrices are classified into different modes based on the voicing vector information of superframe. To improve speech quality, a dynamic bit allocation scheme is developed. Experimental results show that the speech quality of the proposed vocoder is intelligible with good naturalness.