Based on the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) standardization G.729.1,an embedded variable bit-rates stereo speech and audio coding method is proposed in this paper.In this coding algorithm, the middle information and side information of stereo signal are processed separately by G. 729.1 and modified modulated lapped transform coding techniques, the structure of bit-stream is embedded and the bit-stream can be divided into several layers. Wideband stereo signal and super-wideband stereo signal all can be processed by this codec. The maximum bit-rates of wideband stereo signal and super-wideband stereo signal are 48kb/s and 64kb/s, respectively. The test results indicate that the quality of the embedded speech and audio coding algorithm at stereo coding layers is close to Terms of Reference for ITU-T G. EV-VBR stereo codec.%基于国际电信联盟标准化组织(ITU-T)编码标准G.729.1,本文提出了一种嵌入式变速率立体声语音与音频编码方法.本算法利用G.729.1和改进的调制叠接变换(Modulated Lapped Transform,MLT)编码技术对输入信号的中值与边带信息进行分层编码,形成具有嵌入式结构的码流.编码器可处理宽带和超宽带的立体声信号,宽带立体声信号编码的最大码率为48kb/s,超宽带立体声信号编码的最大速率为64kb/s.实现结果表明,本编码器的编码质量均达到了ITU-T对G.EV-VBR立体声编码的指标要求.
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