AMR to G.729A speech transcoding with fast codebook search

• Main Authors: Li-Fang Huang, 黃麗芳
• Other Authors: 張寶基
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/09292227811549153386

碩士 === 國立中央大學 === 通訊工程研究所 === 95 === As the development of the internet technique, we not only can transmit the data but also connect 3GPP with VoIP over internet . Because of the coding schemes of 3GPP are not the same as VoIP, speech transcoding scheme is needed in the voice system over internet. Speech transcoding scheme can make the connection between users successful, and furthermore, it can be used in entertainment applications, such as audio chat rooms and online games. Full decoding technique is an intuitive and traditional speech transcoding method, but it requires high computational complexity and long processing time. In this work, we propose a partial decoding technique with fast codebook search, which utilizes the pulse replacement method, on ACELP coding architecture. There is no need to redo all the decoding and encoding processes. Partial decoding method can be directly applied to ACELP based speech coding, such as AMR and G.729A speech standards. It achieves excellent voice quality as the full decoding method does while it only requires 7.2% computation loading on clockticks per frame.