基于特征波形内插与频带扩展技术的低速率宽带语音编码器

Low Bit Rate Wideband Speech Coder Based on CWI and BWE Techniques

考察了特征波形内插(CWI)算法对于宽带语音编码的扩展能力.分析宽带特征波序列的性质表明,直接使用传统的特征波形内插算法并不适于增强宽带语音的编码效率及对计算复杂度的兼顾,可引入频带扩展(BWE)技术单独处理高频段.宽带语音的高、低频分别由特征波形内插编码和频带扩展算法恢复,由此形成了5.15 kbit/s的低速率宽带语音编码器,增强了语音真实感、辅音的辨析度及对话者的识别度,宽带语音编码质量接近AMR-WB的6.6 kbit/s结果.

The paper investigates the capability of extension of characteristic waveform interpolation （CWI） algorithm to wideband speech coding. The analysis of wideband characteristic waveform sequences shows that using classical CWI algorithm directly is not suitable for enhancing the wideband coding efficiency and affects the computational complexity. The paper introduces bandwidth expansion （BWE） technique to process the high frequency band. High and low frequency bands were recovered separately by CWI and BWE algorithms. The final 5.15 kbit/s low bit rate wideband coder can enhance the trueness of speech, the discriminability of consonants and the recognizability of the speaker. The coding result is close to that of AMR-WB 6.6 kbit/s.