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An efficient transcoding algorithm for AMR and G.723.1 speech coders and performance evaluation  

최진규 (LG전자, 단말연구소)
윤성완 (연세대학교 전기전자공학)
강홍구 (연세대학교 전기전자공학)
윤대희 (연세대학교 전기전자공학과)
Publication Information
Journal of the Institute of Electronics Engineers of Korea SP / v.41, no.4, 2004 , pp. 121-130 More about this Journal
Abstract
In the application requiring the interoperability of different networks such as VoIP and wireless communication system, two speech codecs must work together with the structure of cascaded connection, tandem. Tandem has several problems such as long delay, high complexity and quality degradation due to twice complete encoding/decoding process. Transcoding is one of the best solutions to solve these problems. Transcoding algorithm is varied with the structure of source and target coder. In this paper, transcoding algorithm including the LSP conversion, the pitch estimation and new perceptual weighting filter for reducing complexity and improving qualify is proposed. These algorithms are applied to the pair of AMR md G.723.1. By employing the proposed algorithms in the transcoder, the complexity is reduced by about 20%-58% and quality is improved compared to tandem.
Keywords
AMR; G.723.1;
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