改进的符合EV-VBR标准的嵌入式宽带语音编码器  

Improved embedded wideband speech codec fitting EV-VBR standard

作　　者：辛杰[1] 鲍长春[1] 贾懋珅[1] 刘鑫[1] 

机构地区：[1]北京工业大学电子信息与控制工程学院语音与音频信号处理实验室,北京100124

出　　处：《通信学报》2010年第6期7-13,共7页Journal on Communications

基　　金：国家自然科学基金资助项目(60872027);北京市自然科学基金资助项目(4082006);北京市属高等学校人才强教计划基金资助项目~~

摘　　要：基于国际电信联盟标准化组织(ITU-T)嵌入式变比特率(EV-VBR)编码标准提案,在本实验室开发的候选编码器基础上提出了一套改进的嵌入式变速率宽带语音编码方法。本算法在前2层使用代数码激励线性预测(ACELP)编码,增加计算量化了中间子帧谱参数,设计实现了三脉冲深度优先树搜索算法;在后3个编码层,本算法使用累积频域系数矢量的方式重新构建了嵌入式变换域编码(TCX)。此外,改进编码器还实现了语音激活检测(VAD)和非连续传输(DTX)功能。相关测试表明,改进编码器较原编码器,语音质量有明显改善,编码复杂度显著降低,编解码质量和效率与最新的G.718标准接近,并保持了低延迟的优点。Based on the International Telecommunication Union Telecommunication Standardization Sector（ITU-T） recommendation for EV-VBR coding standard and the candidate codec designed by Speech and Audio Signal Processing Laboratory（SASPL） of Beijing University of Technology,an improved embedded variable bit rates wideband speech codec was proposed.In the improved codec,ACELP coding was implied to the first two coding layers.The middle sub-frame spectral parameters were computed and quantized.Three pulses depth first tree search algorithm was designed.On the higher three coding layers embedded TCX coding was reconstructed by accumulating frequency coefficients vectors.Addition-ally,VAD and DTX functions were implemented in the improved codec.Test results show that the improved codec achieves better speech quality and much lower coding complexity than the original codec.The speech quality and coding efficiency are comparable with G.718 of a new ITU-T speech coding standard and the low delay feature is retained.

关 键 词：语音编码 嵌入式编码 嵌入式ACELP编码 嵌入式TCX编码 

分 类 号：TN912.3[电子电信—通信与信息系统]