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研究生:吳聲旺
研究生(外文):Sheng-Wang Wu
論文名稱:H.264/AVC流量控制演算法在低延遲傳輸環境之應用與改良
論文名稱(外文):Improved Rate Control for Low-Delay Communications in H.264/AVC Video Coding Standard
指導教授:楊竹星楊竹星引用關係
指導教授(外文):Chu-Sing Yang
學位類別:碩士
校院名稱:國立中山大學
系所名稱:資訊工程學系研究所
學門:工程學門
學類:電資工程學類
論文種類:學術論文
論文出版年:2004
畢業學年度:92
語文別:英文
論文頁數:44
中文關鍵詞:Lagrangian最佳化跳張技術流量控制量化參數H.264
外文關鍵詞:Lagrangian optimizationquantization parameterRate controlH.264frame-skipping
相關次數:
  • 被引用被引用:2
  • 點閱點閱:230
  • 評分評分:
  • 下載下載:16
  • 收藏至我的研究室書目清單書目收藏:0
在即時、雙向的視訊傳輸環境中,如何減少傳輸時所造成的延遲是一個非常重要的課題。因為資料流在編碼器的緩衝區中所停留的時間必須非常小,一個可維持高畫質並可避免緩衝區溢位的流量控制演算法是必要的。其中一個可降低緩衝區溢位方法便是略過某幾張影像而不做編碼的動作,以降低緩衝區的使用率,但此舉會造成視覺上的不連續。在此論文中,我們將討論低延遲對於H.264流量控制演算法的影響以及改進的方案。我們發現H.264流量控制演算法對於跳張(frame-skipping)的情形無法處理的很好。為了改進此缺點,我們調整每張I-frame的量化參數來避免緩衝區溢位與跳張的問題。對於一畫面群(GOP)的同一張I-frame而言,使用不同的量化參數(quantization parameter)會對此畫面群產生不同的編碼量(rate)及失真(distortion)大小。針對此一特性,我們使用Lagrangian最佳化來找出可以平衡編碼量和失真大小的最佳解。藉由可預估畫面群之編碼量以及失真的數學模型,針對每張I-frame所有可能的量化參數來計算所產生的Lagrangian成本。對於此張I-frame,具有最小Lagrange成本的量化參數便是最佳的選擇。實驗結果證明,在低延遲環境的限制下,無論在跳張的數目或是畫質方面,我們的方法都比標準的H.264流量控制演算法有更好的效能。
In real-time, two way video communications, how to minimize the end-to-end delay for transmitting video data is very important. Since the delay produced by bits accumulated in the encoder buffer must be very small, we need an improved rate control to encode the video with high quality and maintain low buffer fullness. One approach to reduce the buffer fullness is to skip the encoding frames, but the frame-skipping will produce undesirable motion discontinuity in the encoded video sequence. In this thesis, we study the impact of low delay constraint in H.264 rate control and its improvements. The drawback of the H.264 rate control is it cannot handle the frame-skipping mechanism well. To modify this, we control the quantization parameter of each I-frame to avoid the buffer overflow and frame-skipping. Since encoding the I-frame by different quantization parameter will generate different rate and distortion for a group of pictures (GOP), we use Lagrangian optimization to find the tradeoff between rate and distortion for a GOP. By the estimation models of rate and distortion for a GOP, calculate the Lagrangian cost for each possible quantization parameter of I-frame, the quantization parameter with minimum Lagrangian cost will be our choice for I-frame. Simulation results show that our proposed rate control encode the video sequence with less skipped frames and with higher PSNR compared to H.264 rate control under low delay constraint.
Abstract I
中文摘要 II
Contents III
List of Figures IV
Chapter 1 Introduction and Motivation 1
1.1 Introduction to Rate Control 1
1.2 Introduction to Low Delay Rate Control 3
1.3 Motivation 4
Chapter 2 Background and Relative Work 7
2.1 H.264/MPEG-4 Part 10 7
2.1.1 New Features 7
2.1.2 Introduction to H.264 Encoder 8
2.2 Rate Control for MPEG-4 9
2.2.1 Quadratic Rate Distortion Model 9
2.2.2 Framework of Scalable Rate Control 10
2.2.3 Other Improved Rate Control Schemes for MPEG-4 14
2.3 Rate Control for H.264 16
2.3.1 Terminology 18
2.3.2 Overview to the Rate Control Scheme 19
2.3.3 GOP Layer Rate Control 20
2.3.4 Frame Layer Rate Control 21
2.3.5 Basic Unit Rate Control 23
2.4 Lagrangian Optimization 24
Chapter 3 Rate control for Low Delay Communication 25
3.1 The Proposed Rate Control for Low Buffer Delay 25
3.2 Rate Estimation for I-frame 27
3.3 Distortion Estimation for I-frame and P-frame 33
3.4 QP Estimation for I-frame 35
Chapter 4 Simulation Results 39
Chapter 5 Conclusion and Future Work 42
Reference 43
[1]"Draft ITU-T recommendation and final draft international standard of joint video specification (ITU-T Rec. H.264/ISO/IEC 14486-10 AVC," in Joint Video Team (JVT) of ISO/IEC MPEG and ITU-T VCEG, JVT-G050, 2003.
[2]Iain E.G. Richardson, H.264 and MPEG-4 Video Compression,Wiley, 2003.
[3]T. Wiegand, G. J. Sullivan, G. Bjontegaard, A. Luthra, "Overview of the H.264/AVC Video Coding Standard," IEEE Trans. Circuits Syst. Video Technol., vol 13, pp.560-576, July. 2003.
[4]Hung-Ju Lee, Tihao Chiang and Ya-Qin Zhang, "Scalable Rate Control for MPEG-4 Video," IEEE Trans. Circuits Syst. Video Technol., Vol. 10, pp.878-894, Sept. 2000.
[5]Anthony Vetro, Huifang Sun and Yao Wang, "MPEG-4 Rate Control for Multiple Video Objects," IEEE Trans. Circuits Syst. Video Technol., Vol. 9, pp.186-199, Feb. 1999.
[6]Tihao Chiang and Ya-Qin Zhang, "A New Rate Control Scheme Using Quadratic Rate Distortion Model," IEEE Trans. Circuits Syst. Video Technol., Vol. 7, pp. 246-250, Feb. 1997.
[7]Feng Pan, Z. Li, K. Lim and G. Feng, "A Study of MPEG-4 Rate Control Scheme and Its Improvements," IEEE Trans. Circuits Syst. Video Technol., Vol. 13, pp.440-446, May. 2003.
[8]King N. Nagn, Thomas Meier and Zhenzhong Chen, "Improved Single Video Object Rate Control," IEEE Trans. Circuits Syst. Video Technol., Vol. 13, pp.385-393, May. 2003.
[9]Jordi Ribas-Corbera and Shawmin Lei, "Rate Control in DCT Video Coding for Low-Delay Communication," IEEE Trans. Circuits Syst. Video Technol., vol. 9, pp.172-185, Feb. 1999.
[10]G. J. Sullivan and T. Wiegand, "Rate-Distortion Optimization for Video Compression," IEEE Signal Processing Magazine, vol. 15, pp.74-90, Nov. 1998.
[11]A. Ortega and K. Ramchandran, "Rate-Distortion Methods for Image and Video Compression," IEEE Signal Processing Magazine, vol. 15, pp.23-50, Nov. 1998.
[12]T. Wiegand, M. Lightstone, D. Mukherjee, T. G. Campbell, S. K. Mitra, "Rate-Distortion Optimized Mode Selection for Very Low Bit Rate Video Coding and the Emerging H.263 Standard," IEEE Trans. Circuits Syst. Video Technol., vol. 6, pp.182-190, April. 1996.
[13]Siwei Ma, Wen Gao, Peng Gao and Yan Lu, "Rate Control for Advance Video Coding (AVC) Standard," IEEE International Symposium on Circuits and Systems, vol 2, pp.892-895, May. 2003.
[14]Joint Video Team (JVT) of ISO/IEC MPEG & ITU-T VCEG Document JVT-F086, Dec. 2002.
[15]Z. G. Li, F. Pan, K. P. Lim, G. N. Feng, X. Lin, S. Rahardia and D. J. Wu, "Adaptive Frame Layer Rate Control for H.264," IEEE International Conference on Multimedia and Expo, vol. 1, pp.581-584, July, 2003.
[16]Joint Video Team (JVT) of ISO/IEC MPEG & ITU-T VCEG Document JVT-H014, May. 2003.
[17]Siwei Ma, Wen Gao, Feng Wu and Yan Lu, "Rate Control for JVT Video Coding Scheme with HRD Considerations," IEEE International Conference on Image Processing, vol. 3, pp.793-796, Sept. 2003.
[18]Wei Ding and Bede Liu, "Rate Control of MPEG Video Coding and Recording by Rate-Quantization Modeling," IEEE Trans. Circuits Syst. Video Technol., vol. 6, pp.12-20, Feb. 1996.
[19]JM8.2, H.264/AVC Software Coordination, http://bs.hhi.de/~suehring/tml/
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