【作者】 赵勇；

【导师】 傅丰林；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2002， 硕士

【摘要】 随着LAN、Intranet、Internet在全世界的迅猛发展，IP网络的性能逐步改善，基于IP网络的多媒体通信已经成为未来通信系统重要的研究和发展方向。语音编码作为多媒体通信的一个重要环节正受到人们的广泛关注。G．729A是国际电信联盟新颁布的编码速率为8kb／s的低速率语音压缩编码标准，它是基于IP网络的多媒体会议系统标准H．323可选的语音压缩编码标准之一。本文在对IP网络的特性及G．729A编解码算法进行分析后，提出了用软件来实现语音信号编解码的方案。本方案实现时采用Microsoft公司的新版本DirectX8.0中的DirectSound技术，实现了语音信号的捕获与回放；采用G．729A编解码算法实现了语音信号压缩编解码，并提出了相应的改进措施。系统还将编码和解码部分做成动态链接库，提高了系统处理效率。更多还原

【Abstract】 With the development of LAN, Intranet and Internet and the improvement of IP network performance, the multimedia communication based on IP network has become an important research and development branch of the future communication system. As a basis of multimedia communication, speech coding becomes the focus of discussion. The G729A, a new issued speech compressed coding standard at 8kbit/s, is one of the optional coding standards of H.323, which is multimedia meeting system standard based on IP network.With a view to IP character and G729A coding arithmetic, a speech codec scheme in software is presented in this paper. With the DirectSound technology, an important part of DirectX 8.0, the capturing and playback of speech is achieved. The compressed encoding of speech is implemented with G729A coding arithmetic, together with some relative measures mentioned in the paper. The software module of coding and decoding are linked dynamically to improve the system processing efficiency.更多还原