臺灣博碩士論文加值系統

在未來，超高解析度影片(2K、4K)的觀看需求會被逐漸地提高。假如使用目前
主流的視訊編碼格式H.264進行影像壓縮，會因為H.264使用固定大小的編碼單元，
造成超高解析度影片編碼效率低下的問題。為了因應未來超高解析度影片的觀看需
求，Joint Collaborative Team on Video Coding(JCT-VC)團隊在2012年開發出第一版新的
視訊編碼格式HEVC(High Efficiency Video Coding)來減輕超高解析度影片對儲存設備的
負擔。HEVC使用了可變動大小的編碼單元(Coding Unit, CU)對影片進行更大的壓縮
比。數個CU會組合出最大編碼單元(Largest Coding Unit, LCU)，這是HEVC中最基本的
編碼單元。然而，為了要找出最佳LCU的劃分方式，HEVC嘗試所有的LCU組合方式。
這種作法使得HEVC的編碼時間複雜度明顯地高於H.264。因此，本論文中我們著手於
使用原始畫面亮度預處理來提升編碼器的畫面內編碼之效能。我們利用原始畫面的
複雜度對LCU的劃分進行預測，來達到限制深度探索範圍的目的。對於畫面複雜度的
判斷，我們將包含原始畫面的LCU等份切割為子像素塊，利用離散小波轉換(Discrete
Wavelet. Transform, DWT)的Haar小波轉換分析原始畫面亮度並且將會影響編碼深度的
畫素額外地儲存。利用這些額外的資訊幫助我們限制深度探索的深度。我們的方法可
以在平均僅提高1.44%的BD-Rate情況下，達到平均34.39%的編碼速度提升。

In the future the demand from watching ultra-high resolution videos will increase gradually.
Choosing current major video coding standard, called H.264, to compress video will cause low
performance of compression in bitrate because of fixed macroblocks in H.264. For solving
the large bitrate problem, a new video coding standard called High Efficiency Video Coding
(HEVC) includes a quadtree-based Coding Unit (CU) block partitioning structure is established.
However, HEVC causes a significant increase in computational complexity, compared to H.264
due to the necessity of searching the optimal Largest Coding Unit (LCU) partition. In this
paper, we propose the Fast Luma-based CU Partition (FLCUP) for HEVC intra frame coding,
which reduces significant computational complexity with negligible distortion in rate-distortion
performance. FLCUP performs two steps: 1) analyzing the complexity of an original frame and
2) predicting LCU partition. Current the complexity of an original frame of LCU is analyzed by
Haar Wavelet Transform and several thresholds are obtained from experimental results. After
analyzing the complexity of an original frame, FLCUP could predict the LCU partition for
encoder without the unnecessary depth searching. Experimental results show that compared to
the standard HEVC, FLCUP reduces the computational complexity by 34.39% at the cost of
increasing only 1.44% in BD-Rate.

目次
摘要 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
誌謝 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
目次 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
表目次 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
圖目次 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
一、 導論 (Introduction) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
二、 相關研究 (Related Work) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 快速預測LCU深度區間(Fast Depth Limitation of a LCU) . . . . . . . . . . . 6
2.2 利用RD-Cost參數進行提前終止(Early Termination by the RD-Cost) . . . . . 7
2.3 利用亮度紋理進行預處理(Pre-process by the Luma) . . . . . . . . . . . . . . 8
2.4 總結(Summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
三、 基於畫面亮度之快速CU劃分 (Fast Luma-based CU Partition) . . . . . . . . . . 11
3.1 利用原始畫面亮度做深度限制(Depth Limitation by the Luma of an Original
Frame) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Haar小波轉換(Haar Wavelet Transform) . . . . . . . . . . . . . . . . . . . . 14
3.3 畫面細節擷取(Extracting Details of a Frame) . . . . . . . . . . . . . . . . . . 16
四、 FLCUP實作 (FLCUP Implementation) . . . . . . . . . . . . . . . . . . . . . . . 17
4.1 統計圖、複雜圖與深度圖(Statistics Map、Complexity Map and Depth Map) 17
4.2 LCU的深度預測(Depth Prediction of a LCU) . . . . . . . . . . . . . . . . . . 20
4.3 流程總結(Summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
五、 實驗結果 (Experimental Results) . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.1 實驗環境設定(Experimental Environment) . . . . . . . . . . . . . . . . . . . 23
5.2 效能測試(Performance Testing) . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3 效能比較(Comparison of Performance) . . . . . . . . . . . . . . . . . . . . . 26
5.4 深度預測準確度(Accuracy of Depth Prediction) . . . . . . . . . . . . . . . . 27
5.5 編碼時間效能的分析(Analysis of Encoding Time) . . . . . . . . . . . . . . . 28
5.6 實驗影片的深度分布 (Depth Distribution of Sequences) . . . . . . . . . . . . 30
5.7 實驗總結 (Experimental Summary) . . . . . . . . . . . . . . . . . . . . . . . 31
六、 總結與未來研究 (Conclusion and Future Work) . . . . . . . . . . . . . . . . . . 32
參考文獻 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
附錄一 編碼詳細資料 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
附錄二 RD效能圖 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

[1] G. J. Sullivan, J. R. Ohm, W. J. Han, and T. Wiegand, “Overview of the high efficiency
video coding (HEVC) standard,” IEEE Transactions on Circuits and Systems for Video
Technology, vol. 22, no. 12, pp. 1649–1668, 2012.
[2] T. Sikora, “The MPEG-4 video standard verification model,” IEEE Transactions on
Circuits and Systems for Video Technology, vol. 7, no. 1, pp. 19–31, 1997.
[3] T. Wiegand, “Overview of the H. 264/AVC video coding standard,” IEEE
TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY,
vol. 13, no. 7, pp. 560 –576, 2003.
[4] M. Pourazad, C. Doutre, M. Azimi, and P. Nasiopoulos, “HEVC: The New Gold Standard
for Video Compression: How Does HEVC Compare with H.264/AVC,” IEEE Consumer
Electronics Magazine, vol. 1, no. 3, pp. 36–46, 2012.
[5] G. J. Sullivan, J. M. Boyce, Y. Chen, J.-r. Ohm, C. A. Segall, and A. Vetro, “Standardized
Extensions of High Efficiency Video Coding ( HEVC ),” IEEE Journal on Selected Topics
in Signal Processing, vol. 7, no. 6, pp. 1001–1016, 2013.
[6] S. Ahn, B. Lee, and M. Kim, “A novel fast CU encoding scheme based on spatiotemporal
encoding parameters for HEVC inter coding,” IEEE Transactions on Circuits and Systems
for Video Technology, vol. 25, no. 3, pp. 422–435, 2015.
[7] M. Budagavi, A. Fuldseth, G. Bjontegaard, V. Sze, and M. Sadafale, “Core transform
design in the high efficiency video coding (HEVC) Standard,” IEEE Journal on Selected
Topics in Signal Processing, vol. 7, no. 6, pp. 1029–1041, 2013.
33
[8] G. Correa, P. Assuncao, L. Agostini, and L. A. Da Silva Cruz, “Coding tree depth estimation
for complexity reduction of HEVC,” in Data Compression Conference Proceedings,
2013, pp. 43–52.
[9] G. Correa and P. Assuncao, “Complexity control of HEVC through quadtree depth estimation,”
in IEEE EuroCon 2013, no. July, 2013, pp. 81–86.
[10] X.-q. Huang and C.-h. Kuo, “Adaptive depth search range for HEVC coding unit size
selection,” in Proceedings of 2014 APSIPA Annual Summit and Conference, Siem Reap,
city of Angkor Wat, Cambodia, December 9-12, 2014.
[11] D. Grois, D. Marpe, A. Mulayoff, B. Itzhaky, and O. Hadar, “Performance comparison
of H.265/MPEG-HEVC, VP9, and H.264/MPEG-AVC encoders,” Picture Coding
Symposium, PCS 2013 - Proceedings, pp. 394–397, 2013.
[12] X. Shen, L. Yu, and J. Chen, “Fast coding unit size selection for HEVC based on Bayesian
decision rule,” in 2012 Picture Coding Symposium, PCS 2012, Proceedings, no. 2010,
2012, pp. 453–456.
[13] J. Xiong, H. Li, Q. Wu, and F. Meng, “A fast HEVC inter CU selection method based
on pyramid motion divergence,” IEEE Transactions on Multimedia, vol. 16, no. 2, pp.
559–564, 2014.
[14] A. Ortega and K. Ramchandran, “Rate-distortion methods for: Image and video compression,”
IEEE Signal Processing Magazine, vol. 15, no. 6, pp. 23–50, 1998.
[15] L. Shen, Z. Zhang, and P. An, “Fast CU size decision and PU mode decision algorithm in
HEVC intra coding,” Proceedings - International Conference on Image Processing, ICIP,
vol. 2015-Decem, pp. 1593–1597, 2015.
34
[16] P. K. Ranjan, D. Pacharla, B. Ravindran, and D. Mani, “Quality evaluation of HEVC main
still picture with limited coding tree depth and intra modes,” in Proceedings of the 2014
International Conference on Advances in Computing, Communications and Informatics,
ICACCI 2014, 2014, pp. 338–343.
[17] P. K. Meher, S. Y. Park, B. K. Mohanty, K. S. Lim, and C. Yeo, “Efficient integer DCT architectures
for HEVC,” IEEE Transactions on Circuits and Systems for Video Technology,
vol. 24, no. 1, pp. 168–178, 2014.
[18] D. Ruiz-coll, V. Adzic, G. Fernandez-escribano, H. Kalva, J. L. Mart ´ ´ınez, and P. Cuenca,
“FAST PARTITIONING ALGORITHM FOR HEVC INTRA FRAME CODING USING
MACHINE LEARNING,” in ICIP 2014, 2014, pp. 4112–4116.
[19] J. Kim, Y. Choe, and Y. G. Kim, “Fast coding unit size decision algorithm for intra coding
in HEVC,” in Digest of Technical Papers - IEEE International Conference on Consumer
Electronics, 2013, pp. 637–638.
[20] C. S. Lin, W. J. Yang, and C. W. Su, “FITD: Fast Intra Transcoding from H.264/AVC to
high efficiency video coding based on DCT coefficients and prediction modes,” Journal of
Visual Communication and Image Representation, vol. 38, pp. 130–140, 2016.
[21] H. Zhang, Q. Liu, and Z. Ma, “Priority classification based fast intra mode decision for
high efficiency video coding,” 2013 Picture Coding Symposium, PCS 2013 - Proceedings,
vol. 24, no. 4, pp. 285–288, 2013.
[22] L. Shen, Z. Liu, X. Zhang, W. Zhao, and Z. Zhang, “An effective CU size decision method
for HEVC encoders,” IEEE Transactions on Multimedia, vol. 15, no. 2, pp. 465–470, 2013.
35
[23] S. Cho and M. Kim, “Fast CU splitting and pruning for suboptimal CU partitioning in
HEVC intra coding,” IEEE Transactions on Circuits and Systems for Video Technology,
vol. 23, no. 9, pp. 1555–1564, 2013.
[24] 張 東 東 and 陳 有 為, “CN105491385A,” 2016. [Online]. Available:
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/
cb7ed43e2f74043188bc/CN105491385A.pdf