An Embedded ACELP Speech Coding Based on the AMR-WB Codec

摘要

This letter proposes a new embedded speech coding structure based on the Adaptive Multi-Rate Wideband (AMR-WB) standard codec. The proposed coding scheme consists of three different bitrates where the two lower bitrates are embedded into the highest one. The embedded bitstream was achieved by modifying the algebraic codebook search procedure adopted for the AMR-WB codec. Our proposed method provides the advantage of scalability due to the embedded bitstream while it inevitably requires some additional computation complexity for obtaining two different code vectors of the higher bitrate modes. Our embedded coder shows improved speech qualities for two higher bitrate modes with slightly increased bitrate caused by the decreased coding efficiency of the algebraic codebook compared to the AMR-WB codec.