摘要
基于小波变换提出可分级变速率特征波形内插(CWI)语音编码算法.利用二次B样条双正交小波变换将二维特征波表面分解成不同的时频分辨率空间,将其作为可分级CWI编码方案的增强层,而基本层仅包含线性预测参数、基音周期和功率归一化因子,使CWI编码的输出码流获得可分级变速率的效果.MUSHRA主观听音比较测试表明,随着码率由1.8 kbit/s增加到3.6 kbit/s,基于小波变换的可分级变速率CWI编码器基本层输出可接受的音质,增强层依次使编码音质得到提高.
A scalable variable rate characteristic waveform interpolation （CWI） speech coding algorithm is proposed based on wavelet transform （WT）. The 2-D characteristic waveform surface is decomposed into several spaces with different time-frequency resolution, which serv.es as the enhancement layers of scalable CWI coding scheme. The basic layer only contains linear prediction parameters, pitch cycle and power normalized factors. The scalable WT-CWI coder obtains variable bit rate. MUSHRA subjective listening test showed that with the coding rate increasing from 1.8 kbit/s to 3.6 kbit/s, the basic layer of the proposed scalable variable rate CWI coder outputs acceptable speech quality and the enhancement layers improved the speech quality in turn.
出处
《北京理工大学学报》
EI
CAS
CSCD
北大核心
2008年第6期531-535,共5页
Transactions of Beijing Institute of Technology
基金
国际合作项目
关键词
特征波形内插
可分级变速率
小波变换
B样条双正交小波
characteristic waveform interpolation （CWI）
scalable variable rate
wavelet transform（WT）
B-spline biorthogonal wavelet
