Journal of the Institute of Electronics and Information Engineers (전자공학회논문지)

The Institute of Electronics and Information Engineers (대한전자공학회)
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An Improved Synthesis Method of Parametric Stereo Coding Based on Tonality Information

토널리티 정보를 기반으로 한 파라메트릭 스테레오 부호화의 개선된 합성 기법

  • Lee, Tung chin (School of Electrical and Electronic Engineering, Yonsei University) ;
  • Park, Young-Cheol (Computer and Telecommunications Engineering Division, Yonsei University) ;
  • Youn, Dae Hee (School of Electrical and Electronic Engineering, Yonsei University)
  • 이동금 (연세대학교 전기전자공학과) ;
  • 박영철 (연세대학교 컴퓨터 정보통신공학부) ;
  • 윤대희 (연세대학교 전기전자공학과)
  • Received : 2014.02.08
  • Accepted : 2014.05.25
  • Published : 2014.06.25
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Abstract

In this paper, we propose a synthesis method that can effectively suppress the ambience which affects tonal components in the PS decoder. Ambience component was obtained by using decorrelation filter and the weighting of the ambience in the decoder was determined through IC parameter. However, since the parameters are extracted in the sub-band domain, a low IC value could be analyzed even if the tonal component is dominant. The quality of the output signal may be degraded. To prevent this problem, the tonality was measured in the downmixed signal and the weighting of the ambience components were adjusted appropriately according to the measured tonality index. The performance of the proposed method was evaluated by simulations. Furthermore, the subjective test was performed and the results confirmed that the proposed method offers improved quality.

본 논문에서는 PS의 복호화과정에서 톤 성분에 영향을 주는 잔향 성분을 효과적으로 억제할 수 있는 합성 방법을 제안하였다. PS에서 잔향 성분은 비상관 필터를 이용하여 구할 수 있으며, 부호화단에서 분석된 IC 파라미터를 통해서 합성되는 잔향의 비중이 결정된다. 하지만 파라미터들은 서브밴드 도메인에서 분석되기 때문에, 톤 성분이 존재하는 대역에서도 낮은 IC값이 분석될 수 있고, 이는 출력 신호의 음질 열화를 야기시킨다. 본 논문에서는 이러한 문제를 보완하기 위해 복호화단으로 입력되는 다운믹스 신호의 토널리티를 측정하였고, 이 측정된 값을 통해 합성되는 잔향 성분의 비중을 조절해주었다. 실험은 시뮬레이션 결과를 통해 성능을 검증한 후에 주관적 음질 평가를 수행하였고, 전체적으로 음질 향상이 있음을 확인하였다.

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References

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