DOI QR코드

DOI QR Code

Fast CU Decision Algorithm using the Initial CU Size Estimation and PU modes' RD Cost

초기 CU 크기 예측과 PU 모드 예측 비용을 이용한 고속 CU 결정 알고리즘

  • Yoo, Hyang-Mi (Dept. of Electronic Engineering, Chungbuk National University) ;
  • Shin, Soo-Yeon (Dept. of Electronic Engineering, Chungbuk National University) ;
  • Suh, Jae-Won (Dept. of Electronic Engineering, Chungbuk National University)
  • Received : 2014.04.17
  • Accepted : 2014.05.23
  • Published : 2014.05.30

Abstract

High Efficiency Video Coding(HEVC) obtains high compression ratio by applying recursive quad-tree structured coding unit(CU). However, this recursive quad-tree structure brings very high computational complexity to HEVC encoder. In this paper, we present fast CU decision algorithm in recursive quad-tree structure. The proposed algorithm estimates initial CU size before CTU encoding and checks the proposed condition using Coded Block Flag(CBF) and Rate-distortion cost to achieve the fast encoding time saving. And, intra mode estimation is also possible to be skipped using the CBF values acquired during the inter PU mode estimations. Experiment results shows that the proposed algorithm saved about 49.91% and 37.97% of encoding time according to the weighting condition.

HEVC는 재귀적 쿼드 트리 구조를 갖는 CU를 부호화에 적용함으로써 높은 부호화 효율을 얻었다. 그러나 이러한 재귀적 쿼드 트리 구조는 HEVC의 부호화 복잡도를 매우 증가시키는 결과를 가져왔다. 본 논문에서는 이러한 재귀적 쿼드 트리 구조 안에서 빠른 CU 결정이 가능한 알고리즘을 제안한다. 제안하는 알고리즘은 CTU 부호화가 이루어지기 전에 미리 초기 CU 크기를 예측하고, CU 부호화 과정에서 CBF와 PU 모드 예측 비용을 이용한 조건을 확인하여 고속 CU 결정이 이루어지도록 한다. 또한 인터 PU 모드 예측과정에서 얻은 CBF값들을 이용하여 인트라 모드 예측 생략이 가능하다. 실험결과, 제안한 알고리즘의 조건에 포함된 가중치값에 따라 최대 평균 49.91%, 37.97%의 부호화 시간 감소 효과를 얻을 수 있었다.

Keywords

References

  1. B. Bross, W.-J. Han, G. J. Sullivan, J.-R. Ohm, and T. Wiegand, WD9: Working Draft 9 of High Efficient Video Coding (HEVC), Document JCTVC-K1003, Shanghai, CN, October 2012.
  2. B. Li, G. J. Sullivan and J. Xu, Comparison of Compression Performance of HEVC Draft 9 with AVC High Profile and Performance of HM9.0 with Temporal Scalability Characteristics, Document JCTVC-L0322, Geneva, CH, January 2013.
  3. G. J. Sullivan, J.-R. Ohm, W.-J. Han, and T. Wiegand, Overview of the High Efficiency Video Coding (HEVC) Standard, IEEE Trans. Circuits Syst. Video Technol., vol. 22, no. 12, pp. 1649-1668, December 2012. https://doi.org/10.1109/TCSVT.2012.2221191
  4. K. McCann, B. Bross, I. K. Kim, S. I. Sekiguchi, W. J. Han, HM5: High Efficiency Video Coding (HEVC) Test Model 5 Encoder Description, Document JCTVC-G1102, Geneva, CH, November 2011.
  5. R. H. Gweon ,Y. L. Lee, and J. Lim, Early Termination of CU Encoding to Reduce HEVC Complexity, Document JCTVC-F045, Torino, IT, July 2011.
  6. R. H. Gweon ,Y. L. Lee, Early Termination of CU Encoding to Reduce HEVC Complexity, IEICE Trans. Fundamentals of Electronics, Communications and Computer Sciences, vol. E95-A, no. 7, pp. 1215-1218, July 2012. https://doi.org/10.1587/transfun.E95.A.1215
  7. K. Choi, S. H. Park, and E. S. Jang, Coding tree pruning based CU early termination, Document JCTVC-F092, Torino, IT, July 2011.
  8. K. Choi and E. S. Jang, Fast coding unit decision method based on coding tree pruning for high efficiency video coding, SPIE Optical Engineering, vol. 51, no. 3, pp. 030502-1-030502-3, March 2012. https://doi.org/10.1117/1.OE.51.3.030502
  9. J. Yang, J. Kim, K. Won, H. Lee, and B. Joen, Early SKIP Detection for HEVC, Document JCTVC-G543, Geneva, CH, Novemver 2011.
  10. J. Kim, J. Yang, K. Won, and B. Joen, Early Determination of Mode Decision for HEVC, Picture Coding Symposium, Krakow, Poland, pp. 449-452, May 2012.
  11. J. Kim, S. Jeong, S. Cho, and J. S. Choi, Adaptive Coding Unit Early Termination Algorithm for HEVC, IEEE International Conference on Consumer Electronics, Las Vegas, USA, pp.261-262, January 2012.
  12. H. M Yoo and J. W. Suh, "Fast Coding Unit Decision Algorithm Based on Inter and Intra Prediction Unit Termination for HEVC," IEEE International Conference on Consumer Electronics, Las Vegas, USA, pp.302-303, January 2013.
  13. Woo-Jin Han, "Conditional Probability Based Early Termination of Recursive Coding Unit Structures in HEVC", JBE, Vol.17, No. 2, pp. 354-362, 2012, March.