Journal of the Institute of Electronics Engineers of Korea SP (대한전자공학회논문지SP)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Real-time Implementation of the AMR-WB+ Audio Coder using ARM Core(R)

ARM Core(R)를 이용한 AMR-WB+ 오디오 부호화기의 실시간 구현

  • 원양희 (삼성전자 정보통신총괄) ;
  • 이형일 (LG전자 CTO 사업부) ;
  • 강상원 (한양대학교 전자컴퓨터공학부)
  • Published : 2009.05.25
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Abstract

In this paper, AMR-WB+ audio coder is implemented, in real-time, using Intel 400MHz Xscale PXA250 with 32bit RISC processor ARM9E-J(R)core. The assembly code for ARM9E-J(R)core is developed through the serial process of C code optimization, cross compile, assembly code manual optimization and adjusting the optimized code to Embedded Visual C++ platform. C code is trimmed on Visual C++ platform. Cross compile and assembly code manual optimization are performed on CodeWarrior with ARM compiler. Through these stages the code for both ARM EVM board and PDA is implemented. The average complexities of the code are 160.75MHz on encoder and 33.05MHz on decoder. In case of static link library(SLL), the required memories are 65.21Kbyte, 32.01Kbyte and 279.81Kbyte on encoder, decoder and common sources, respectively. The implemented coder is evaluated using 16 test vectors given by 3GPP to verify the bit-exactness of the coder.

본 논문에서는 AMR Core(R)를 이용해서 AMR-WB+ 오디오 부호화기를 실시간 구현하였다. 구현 시 사용된 최적화 방법은 어셈블리어 단계에서 수행되었고, latency를 제거하고 32비트 레지스터를 사용하였다. 구현된 음성 부호화기는 평균 복잡도가 ARM9E 버전에서 인코더 160.76MHz, 디코더 33.05MHz으로 총 193.81MHz로 측정되었다. 사용된 ROM의 크기는 인코더 65.21Kbyte, 디코더 32.01Kbyte, 공통소스 279.81Kbyte이다. 구현된 AMR-WB+ 소스 코드는 3GPP에서 제공하는 테스트 벡터들을 CodeWarrior와 목표 PDA 상에서 모두 bit-exact하게 통과함을 보임으로써 검증되었다.

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References

  1. GSM 06.90 "Digital cellular telecommunication system;AdaptiveMulti-Ratespeech Transcoding," 2000
  2. 3GPP TS 26.190, "AMR Wideband Speech codec Transcoding Functions (Release 5)," 2001
  3. B.S. Atal and M.R. Schroeder, "Stochastic coding of speech at very low bit rate," Proc. Int. Conf. Comm., Amsterdam, pp.1610-1613, 1984
  4. 3GPP TS 26.401, "Enhanced aacPlus general audio codec General description,' 2006
  5. 3GPP TS 26.290, "Extended Adaptive Multi-Rate Wideband (AMR-WB+) codec; Transcoding functions," 2006
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