臺灣博碩士論文加值系統

本研究提出一個超精細顆粒可適性 (Fine Granularity Scalability，簡稱FGS) 視訊編碼位元率控制的混合法並探討其品質最佳化策略。FGS屬於可適性編碼且首度由MPEG-4標準提出；由於MPEG-4對FGS位元率控制機制採用的是「位元平面疊加數目法」，且其最大疊加數目只有4，位元率控制之彈性與編碼效率之動態範圍有限。因此，本研究的目的在於如何透過新的位元率控制方法與整體策略更細緻地控制與提昇可適性視訊品質。本研究提出結合「位元平面疊加數目」與「DCT頻譜係數數目」之混合選擇法；根據當前可用頻寬，前者可按選定之疊加總數優先傳送高重要性之位元平面，後者則根據Zigzag Truncation 統一截斷所有選定傳送之位元平面以在更大動態範圍中提供更彈性的位元率控制。透過此兩者之調整，根據可用頻寬呈現了不同條件下彈性位元率之相應動態範圍，並探討本研究設計之FGS編碼器的編碼效率 (Coding Efficiency)。
就FGS的系統架構而言，其視訊基本層乃採用H.264壓縮標準，並由量化參數或位元率參數決定位元率，以提供基本視訊品質。接著，由原始視訊與基本層解碼視訊之差值獲得差分視訊，並做為FGS編碼器提升層之輸入視訊。此差分視訊再藉由我們提出的混合方法在FGS編碼器提升層產生更彈性的視訊串流位元率。本研究也針對通道的可用頻寬 (具有時變性)，探討FGS基本層與提升層之頻寬分配比例對整體視訊品質最佳化策略；以及在不同的可用頻寬動態範圍，本編碼器如何根據編碼效率的最佳化策略，可實現的彈性位元率控制的。因此，本研究對視訊串流品質的可適性與最佳化控制具有重要意義。

This research proposes a hybrid method of bit rate control for Fine Granularity Scalability (FGS) video coding and explores its best quality strategy. FGS is scalable and first proposed by the MPEG-4 standard; since MPEG-4 adopts the number of bit planes as the FGS bit rate control mechanism and the maximum number of bit planes is only up to 4, its bit rate control flexibility and dynamic range of coding efficiency are limited. Thus, the goal of this research is how to control and enhance the scalable video quality in more detail using a new bit rate control method and its overall strategy. This research proposes the hybrid method combining selections of the number of bit planes and the number of DCT frequency coefficients, where based on the current available bandwidth the former transmits the selected bit planes in the order of their importance, and the latter determines the Zigzag Truncation length of all the selected bit planes to gain a more flexible bit rate control in a wider dynamic range. Through the adjustment of these two factors, the dynamic range of fine bit rate control according to available bandwidth is presented, and the coding efficiency of the FGS coder designed by this research is also discussed under different conditions.
As for the FGS system architecture, its base level is created by the H.264 standard, the bit rate of which is determined by the quantization parameter or bit rate parameter to provide the basic video quality. Then the differential video is obtained from the difference of the original video and the decoded base layer at the encoder, and is used as the input of the enhancement layer of the FGS encoder. This differential video can be used to generate a fine rate control of video streaming at the FGS enhancement layer over a wider dynamic range based on our proposed hybrid method. With respect to the time-varying bandwidth of the channel, this research also discusses the optimal strategy of the overall video quality based on the bit-rate-allocated ratio of the FGS base layer to enhancement layer; it also discusses the conceptual design of implementing the fine bit rate control based on the coding efficiency over different dynamic ranges of available bandwidth. Thus this research is meaningful and important to the adaptation of and optimal control of video streaming.

1 緒論1
1.1 研究目標1
1.2 研究動機1
1.3 本研究貢獻3
1.4 論文架構3
2 研究背景與文獻探討4
2.1 視訊可適性編碼4
2.1.1 資料分割5
2.1.2 時間可適性編碼5
2.1.3 空間可適性編碼6
2.2 FGS視訊壓縮技術 7
2.3 H.264視訊壓縮技術8
2.3.1 H.264發展歷程與架構9
2.3.2 H.264視訊編碼原理與核心技術11
2.4 FGS文獻探討12
2.5 本研究之定位13
3 研究方法15
3.1 FGS通訊系統架構 15
3.2 FGS 編碼器設計16
3.2.1 DCT (Discrete Cosine Transform) 轉換18
3.2.2 Zigzag scan19
3.2.3 位元平面分解20
3.2.4 Run Length 與End of Plane21
3.2.5 霍夫曼編碼 (Huffman coding)22
3.3 FGS 解碼器原理與設計23
3.4 位元率控制方法24
3.4.1 位元平面疊加數目與頻譜係數數目之混合選擇法25
3.5 FGS動態範圍研究方法26
3.5.1 應用於獨立編碼器之全視訊動態範圍研究26
3.5.2 應用於H.264之差分視訊動態範圍研究27
3.6 實驗環境27
4 實驗結果與分析30
4.1 FGS 位元率控制動之態範圍測量分析30
4.1.1 差分視訊影像位元率之動態範圍分析 31
4.1.2 全視訊位元率之動態範圍分析37
4.2 FGS之編碼效率分析43
4.3 FGS編碼效率最佳化及位元率控制策略46
4.4 FGS視訊品質穩定度分析51
5 結論與展望54
5.1 結論54
5.2 展望55
參考文獻56

[1] M. Ghanbari, “Video Coding – An Introduction to Standard Codecs,” The Institution of Electrical Engineers, 1999.
[2] F. Pereiera and E. Touradj, “The MPEG–4 Book. Upper Saddle River,” NJ:Prentice Hall, 2002.
[3] M. Reisslein, J. Lassetter, S. Ratnam, O. Lotfallah, F. Fitzek, and S. Panchanathan, “Traffic and quality characterization of scalable encoded video: A large-scale trace-Based study,” Arizona State University, Dept. of Electrical Eng., Tech. Rep., Dec. 2002.
[4] M. Ghanbari, “Layered coding,” in Compressed Video over Networks, M.-T. Sun and A.R. Reibman, Eds. Marcel Dekker, 2001, pp. 251–308.
[5] W. Li, “Fine granularity scalability using bit-plane coding of DCT coefficients,” ISO/IEC JTC1/SC29/WG11, MPEG98/M4204, Dec.1998.
[6] W. Li, “Overview of Fine Granularity Scalability in MPEG-4 Video Standard,” IEEE trans. on Circuits and Syst. Video Technol, vol.11, no.3, pp. 301-317, Mar. 2001.
[7] R. Rejaie, D. Estrin, and M. Handley, “Quality adaptation for congestion controlled video playback over the internet,” in Proceedings of ACM SIGCOMM, Cambridge, MA, Sept. 1999, pp. 189–200.
[8] D. Saparilla and K.W. Ross, “Optimal streaming of layered video,” in Proceedings of IEEE INFOCOM, Tel Aviv, Israel, Mar. 2000, pp. 737–746.
[9] V. Goyal, “Multiple description coding: Compression meets the network,” IEEE Signal Processing Magazine, vol. 18, pp. 74–91, Sept. 2001.
[10] A. Vitali , “ Multiple Description Coding – a new technology for video streaming over Internet,” EBU Technical Review No. 312, October 2007.
[11] F.H.P. Fitzek and B. Can and R. Prasad and M. Katz. “Overhead and Quality Measurements for Multiple Description Coding for Video Services,” Wireless Personal Multimedia Communications WPMC, Italy, 2004, pp. 524-528.
[12] ISO/IEC 13818–2, “Generic coding of moving pictures and associated audio information,” draft International Standard, 1994.
[13] T. Sikora, “MPEG Digital Video-Coding Standards,” IEEE Signal Processing Magazine, Sept. 1997.
[14] ITU-T Recommendation H.261, “Video Codec for Audiovisual Services at p x 64 kbit/s,” March 1993.
[15] ITU-T Recommendation H.263, “Video Coding for Low Bit Rate Communication,” version 1, Nov. 1995; version2, Jan. 1998; version 3, Nov. 2000.
[16] ISO/IEC International Standard 11172-2, “Information technology – Coding of moving pictures and associated audio for digital storage media up to about 1.5 Mbits/s – Part 2: Video,” first edition, Aug. 1993.
[17] ISO/IEC International Standard 13818-2, “ Generic coding of moving pictures and associated audio – Part 2: Video,” 1995.
[18] I. Moccagatta, S. Soudagar, J. Liang, and H. Chen, “Error-Resilient Coding in JPEG-2000 and MPEG-4,” IEEE J. Select. Areas Commun., vol. 18, no. 6, pp. 899-914, Jun. 2000.
[19] ISO/IEC JTC1/SC29/WG11, “MPEG-4 Video Verification Model version 18.0,” N3908, Jan. 2001.
[20] ISO/IEC International Standard 14496-2, “Information technology – Coding of audio-visual objects – Part 2: Visual,” Amendment 1: Visual extensions, July 2000.
[21] ISO/IEC International Standard 14496-10, “Information technology – Coding of audio-visual objects – Part 10: Advanced Video Coding, third edition,” Dec. 2005, corrected version, March 2006.
[22] T. Wiegand, G.J. Sullivan, G. Bjøntegaard, and A. Luthra, “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, July 2003.
[23] A. R. Reibman, U. Bottou, and A. Basso, “Dct-based scalable video coding with drift,” in Proceedings of IEEE International Conference on Image Processing (ICIP), vol. 2, Thessaloniki, Greece, Oct. 2001, pp. 989–992.
[24] J. Ascenso, F. Pereira “H.264/AVC Fine Grain Scalability Using Bitplane Coding,” 5th International Workshop on Image Analysis for Multimedia Interactive Services, Lisbon, April 2004.
[25] S. Parthasarathy and H. Radha, “Optimal rate control methods for fine granularity scalable video,” in ICIP, vol. 2, Sept.2003, pp. 805-809.
[26] Wen-Nung Lie, Cheng-Hsiung Tseng, Tom C.I. Lin, Ming-Yang Tseng, and I-Cheng Ting, “Rate-Distortion-Smoothness Optimized Rate Allocation Schemes for Spectral Fine Granular Scalable Video Coding Technique,” Journal of Visual Communication and Image Representation, Vol.17, No.4, pp. 799-829, 2006.
[27] F. Wu, S. Li, and Y.Q. Zhang, “A framework for efficient progressive fine granularity scalable video coding,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 11, no. 3, pp. 332–344, Mar. 2001.
[28] Q. Zhang, W. Zhu, and Y.Q. Zhang, “Resource allocation for multimedia streaming over the internet,” IEEE Transactions on Multimedia, vol. 3, no. 3, pp. 339–355, Sept. 2001.
[29] D. Wu, Y.T. Hou, W. Zhu, Y.Q. Zhang, and J.M. Peha, “Streaming video over the internet: Approaches and directions,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 11, no. 3, pp. 1–20, Mar. 2001.
[30] ITU-T T.81, “Information Technology – Digital Compression and Coding of Continuous-Tone Still Images – Requirements and Guidelines,” Sept. 1992.
[31] W.B. Pennebaker and J.L. Mitchell, “JPEG Still Image Data Compression Standard,” Kluwer Academic Press, 1993.
[32] D.A. Huffman, “A method for the construction of minimum-redundancy codes,” in Proceedings of the I.R.E., Sept. 1952, pp. 1098-1102.
[33] Video Trace Library. Available: http://trace.eas.asu.edu/yuv/.