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고효율 비디오 부호화를 위한 적응적 인-루프 필터 방법

Adaptive In-loop Filter Method for High-efficiency Video Coding

  • 정광수 (광운대학교 컴퓨터공학과) ;
  • 남정학 (광운대학교 컴퓨터공학과) ;
  • 임웅 (광운대학교 컴퓨터공학과) ;
  • 조현호 (광운대학교 컴퓨터공학과) ;
  • 심동규 (광운대학교 컴퓨터공학과) ;
  • 최병두 (삼성전자(주) DMC연구소) ;
  • 조대성 (삼성전자(주) DMC연구소)
  • Jung, Kwang-Su (Dept. of Computer Engineering, Kwangwoon University) ;
  • Nam, Jung-Hak (Dept. of Computer Engineering, Kwangwoon University) ;
  • Lim, Woong (Dept. of Computer Engineering, Kwangwoon University) ;
  • Jo, Hyun-Ho (Dept. of Computer Engineering, Kwangwoon University) ;
  • Sim, Dong-Gyu (Dept. of Computer Engineering, Kwangwoon University) ;
  • Choi, Byeong-Doo (Digital Media & Communication R&D Center, Samsung Electronics Co., Ltd.) ;
  • Cho, Dae-Sung (Digital Media & Communication R&D Center, Samsung Electronics Co., Ltd.)
  • 투고 : 2010.06.16
  • 심사 : 2011.01.21
  • 발행 : 2011.01.30

초록

본 논문에서는 고효율의 비디오 부호화를 위한 적응적인 인-루프 필터 방법을 제안한다. 최근 비디오 부호화 표준화 단체에서는 영상의 부호화 후 복원된 영상과 원본 영상과의 평균 제곱 오차(mean square error) 관점에서 오차를 최소화하는 Wiener 필터기반의 post-filter hint SEI 메시지 방법과 블록 기반의 필터 제어 방법 (block-based adaptive filter control, BAFC)에 대한 연구가 있었다. Post-filter hint SEI 메시지 방법은 후처리 필터로서 프레임간의 예측 오차를 줄이지 못하는 문제점이 있으며, BAFC 방법은 기존 H.264/AVC의 디블록킹 필터와 독립적으로 동작하기 때문에 인코더 및 디코더 영역에서 높은 연산 복잡도를 차지하는 문제점이 있다. 본 논문에서는 기존 H.264/AVC의 디블록킹 필터와 문맥 기반으로 설계한 인-루프 필터를 적응적으로 사용함으로써 복잡도를 낮추고 부호화 효율을 높이는 인-루프 필터 방법(Low-complexity adaptive in-loop filter, LCALF)을 제안한다. 실험결과에서 제안하는 방법은 기존 방법보다 평균적으로 약 1% 정도의 비트 감소를 보이고, 동시에 디코더 영역에서 약 22% 정도의 낮은 연산 복잡도를 보인다.

In this paper, we propose an adaptive in-loop filter to improve the coding efficiency. Recently, there are post-filter hint SEI and block-based adaptive filter control (BAFC) methods based on the Wiener filter which can minimize the mean square error between the input image and the decoded image in video coding standards. However, since the post-filter hint SEI is applied only to the output image, it cannot reduce the prediction errors of the subsequent frames. Because BAFC is also conducted with a deblocking filter, independently, it has a problem of high computational complexity on the encoder and decoder sides. In this paper, we propose the low-complexity adaptive in-loop filter (LCALF) which has lower computational complexity by using H.264/AVC deblocking filter, adaptively, as well as shows better performance than the conventional method. In the experimental results, the computational complexity of the proposed method is reduced about 22% than the conventional method. Furthermore, the coding efficiency of the proposed method is about 1% better than the BAFC.

키워드

참고문헌

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