本論文首先針對降維框內畫面(intra-frame) 非H.264/AVC到H.264/AVC轉碼提出聯合轉換域轉碼(Jiont Transform-domain Transcoding)演算法，它有效結合8 8反離散餘弦轉換(Discrete Cosine Transfrom)、降維器以及4 4整數轉換(Integer Transform)。同時，我們也提出聯合轉換域轉碼演算法的快速實現法，以進一步减少實現本身演算法的計算量，與先前提出之方法相比較，所提出轉碼演算法可節省大量的計算量。
一般而言，位元率–失真的成本估測於H.264/AVC編碼上是常用的方法，其有效達到最佳位元率–失真(Rate-Distortion Optimization)之編碼模式的選擇及位元率的最佳控制。因此，本論文第二部分提出較準確的位元預測模型與可適性演算法以預測框內或框間方塊(inter-block)的編碼位元數。本位元估測模型是以現有的編碼參數來做線性組合，以更精準於描述熵編碼及轉換係數相關編碼參數所形成的位元估測。最後，更提出一精準的位元率–失真成本預測函式，配合提出方塊分類的方法，以增加所提出方法的有效性。
本論文第三部分提出轉換域轉換演算法，直接將MPEG-2之8x8離散餘弦轉換係數轉碼至H.264/AVC之4x4整數轉換係數，再將轉碼後的係數以所提出的位元率–失真的成本估測函數以完成MPEG-2到H.264/AVC降維轉碼器之複雜度及效能改善。實驗結果顯示，所提出的聯合轉換域轉碼演算法有效的將MPEG-2框內畫面轉換至H.264/AVC的框內畫面。若與像素域中包含MPEG-2解碼器、像素域中的降尺寸以及H.264/AVC編碼器的解碼–降維–編碼轉碼器相比，本法得到幾乎與之相同的PSNR效能。另外，位元估測與成本預測函式的實驗也顯示出，所提出的方法與先前所提出的方法相比較，可獲得較佳的位元與位元–失真成本的預估結果。

In this dissertation, we propose a joint transform-domain translated (JTT) algorithm, which can achieve non-H.264/AVC to H.264/AVC downscaling intra-frame transcoding. The proposed JTT algorithm effectively combines 8 8 inverse discrete cosine transform (DCT), downscaler, and 4 4 integer-transform without involving any complex spatial-domain pixel processes. Besides, we also suggest a fast JTT algorithm to further reduce the computation. The proposed transcoding method saves a lot of computation compared to some existed approaches in transcoding processing.
Generally, the rate-distortion cost estimation, which is useful to fasten H.264/AVC encoding, could be used to achieve rate-distortion optimization (RDO) for mode-decision and rate-control. In the second part, we propose a new rate-prediction model and an adaptive algorithm to provide more accurate estimation of the number of coding bits for encoding intra and inter-blocks compared to the previously-proposed methods. The rate estimation is modeled by a linear combination of existing coding parameters, which achieve a more accurate model to characterize the entropy coding and transform coefficients. Based on the proposed model, a cost estimation function is finally proposed to achieve a more accurate rate-distortion cost estimation. Furthermore, we propose a block classification approach to further improve the effectiveness of the proposed scheme.
In the third part, we adopt the JTT algorithm directly translated MPEG-2 8 8 DCT coefficients to H.264/AVC 4 4 integer-transform coefficients, which are then plug into the proposed rate-prediction model to estimate the number of coding bits and compute R-D cost estimation to reduce the RDO computation and improve the performance for MPEG-2 to H.264/AVC downscaling transcoder. Experimental results show that the proposed JTT algorithm effectively converts MPEG-2 intra-frame into H.264/AVC intra-frame to achieve almost identical PSNR performance compared to the traditional and complex decode-downsize-encode (DDE) transcoder, which involves MPEG-2 decoding, spatial-domain down-sizing in the pixel domain, and H.264/AVC encoding processes. In addition, experimental results to evaluate the proposed bit-rate and cost estimations show that the proposed schemes can achieve better results in estimating the bit-rate and rate-distortion cost compared to previously proposed approaches.

1 Information Technology-Coding of Moving Pictures and Associated Audio for Digital Storage Media at up to About 1.5 Mbit/s: Video, ISO/IEC 11172-2 (MPEG-1 Video), 1993.
2 Information Technology-Generic Coding of Moving Pictures and Associated Audio Information: Video, ISO/IEC, 13818-2-ITU-T Rec. H.262 (MPEG-2 Video), 1995.
3 Information Technology-Generic Coding of Audio-Visual Objects Part 2: Visual, ISO/IEC 14496-2 (MPEG-4 Video), 1999.
4 Video Codec for audiovisual services at p×64 Kbits/s, ITU-T Recommendation H.261), Sep. 1990.
5 Video coding for low bitrate communication, ITU-T Recommendation H.263 Version 1, 1995. Version 2), Sep. 1997.
6 Draft ITU-T Recommendation and Final Draft International Standard of Joint Video Specification, Document JVT-G050.doc, ITU-T Rec.H.264 | ISO/IEC 14496-10 AVC, Joint Video Team (JVT) of ISO/IEC MPEG and ITU-T VCEG, Mar. 2003.
7 A. Vetro, C. Christopoulos, and H. Sun, “Video transcoding architectures and tech-niques: an overview,” IEEE Signal Proces. Mag., vol. 20, no. 2, pp. 18-29, Mar. 2003.
8 N. Bjork and C. Christopoulos, “Transcoder architectures for video coding,” IEEE Trans. Consumer Electron., vol. 44, pp. 88-98, Feb. 1998.
9 J. Xin, C. W. Lin, and M. T. Sun, “Digital video transcoding,” Proc. of the IEEE, vol. 93, pp. 84-97, Jan. 2005.
10 T. Shanableh and M. Ghanbari, “Transcoding of video into different encoding for-mats,” in Proc. IEEE Int. Conf. Acoust., Speech, and Signal Processing, vol. 6, Jun. 2000, pp. 1927-1930.
11 I. Ahmad, X. Wei, Y. Sun, and Y. Q. Zhang, “Video transcoding: an overview of various techniques and research issues,” IEEE Trans. Multimedia, vol. 7, no. 5, pp. 309-319, Oct. 2005.
12 Digital Video Broadcasting (DVB), Transmission System for Handheld Terminals (DVB-H), Specification 1.1.1, ETSI EN 302 304, V.1.1.1.
13 H. Kalva, “Issues in H.264/MPEG-2 video transcoding,” in Proc. of IEEE Consumer Commun. and Networking, Jan. 2004, pp. 5-8.
14 P. Rault and P. N. Topiwala, “MPEG to H.264 transcoding,” in Proc. of SPIE, vol. 5558, Aug. 2004, pp. 567-578.
15 G. Chen, Y. Zhang, S. Lin, and F. Dai, “Efficient block size selection for MPEG-2 to H.264 transcoding,” in Proc. of the 12th Annual ACM International Conf. on Multi-media, Oct. 2004, pp. 300-303.
16 J. Xin, A. Vetro, and H. Sun, “Converting DCT coefficients to H.264/AVC transform coefficients” in IEEE Pacific-Rim Conf. on Multimedia (PCM’04), Tokyo, Japan, Nov. 2004, pp. 939-946.
17 J. Xin, A. Vetro, and H. Sun, “Efficient macroblock coding-mode decision for H.264/AVC video coding,” in Proc. Picture Coding Symp. (PCS’04), San Francisco, CA, Dec. 2004, pp 53-58.
18 B. Shen, “From 8-tap DCT to 4-tap integer-transform for MPEG to H.264/AVC transcoding”, in Proc. IEEE Int. Conf. on Image Processing (ICIP’04), Singapore, May 2004, pp. 115-118.
19 C. Chen, P. H. Wu, and H. Chen, “MPEG-2 to H.264 transcoding,” in Proc. Picture Coding Symp. (PCS’04), San Francisco, CA, Dec. 2004, pp 15-17.
20 P. Yin, A. Vetro, B. Liu, and H. Sun, “Drift compensation for reduced spatial resolu-tion transcoding,” IEEE Trans. Circuits and Syst. Video Technol., vol. 12, no. 11, pp. 1009-1020, Nov. 2002.
21 R. Dugad and N. Ahuja, “A fast scheme for image size change in the compressed do-main,” IEEE Trans. Circuits and Syst. Video Technol., vol. 11, pp. 461-474, Apr. 2001.
22 Y. K. Lee, S. S. Lee, and Y. L. Lee, “MPEG-4 to H.264 transcoding using macrob-lock statistics,” in Proc. IEEE Int. Conf. on Multimedia and Expo. (ICME’06), Can-ada, July 2006, pp. 57-60.
23 C. W. Ho, O. C. Au, S-H. G. Chan, H. M. Wong and S. K. Yip, “Improved refinement search for H.263 to H.264/AVC transcoding based on the minimum cost tendency search,” in Proc. IEEE Int. Symp. on Circuits and Syst. (ISCAS’06), Greece, May 2006, pp. 5275-5278.
24 N. I. Cho and S. U. Lee, “Fast algorithm and implementation of 2-D discrete cosine transform,” IEEE Trans. Circuits and Syst. Video Technol., vol. 38, pp 297-305, Mar. 1991.
25 A. Hallapuro and M. Karczewicz, “Low Complexity Transform and Quantization”, document JVT-B038.doc and JVT-B039.doc, Joint Video Team (JVT), Jan. 2002.
26 G. Chen, S. X. Lin, Y. D. Zhan and G. Cao, “An new coefficients transform matrix for the transform domain MPEG-2 to H.264/AVC transcoding,” in Proc. IEEE Int. Con. on Multimedia and Expo (ICME’06), Canada, July 2006, pp. 321-324.
27 Y. Su, J. Xin, A. Vetro, and H. Sun, “Efficient MPEG-2 to H.264/AVC intra transcoding in transform-domain,” in Proc. IEEE Int. Symp. on Circuits and Syst. (ISCAS’05), Kobe, May 2005, pp. 1234-1237.
28 C. H. Tseng, H. M. Wang, and J. F. Yang, “Enhanced intra-4×4 mode decision for H.264/AVC coders,” IEEE Trans. Circuits and Syst. Video Technol., vol. 16, pp. 1027-1032, Aug. 2006.
29 I. Choi, J. Lee, and B. Jeon, “Fast coding mode selection with rate-distortion optimi-zation for MPEG-4 Part-10 AVC/H.264,” IEEE Trans. Circuits and Syst. Video Tech-nol., vol. 16, pp. 1557-1561, Dec. 2006.
30 K. P. Lim, S. Wu, D. J. Wu, S. Rahardja, X. Lin, F. Pan, and Z. G. Li, “Fast inter mode selection”, document JVT-I020.doc, Joint Video Team (JVT), Sep. 2003.
31 D. Wu, F. Pan, K. P. Lim, S. Wu, Z. G. Li, X. Lin, S. Rahardja, and C. C. J. Kuo, “Fast intermode decision in H.264/AVC video coding,” IEEE Trans. Circuits and Syst. Video Technol., vol. 15, pp. 953-958, July. 2005.
32 J. R. Corbera and S. Lei, “Rate control in DCT video coding for low-delay communi-cations,” IEEE Trans. Circuits and Syst. Video Technol., vol. 9, pp.172-185, Feb. 1999.
33 S. C. Chang, J. F. Yang, C. F. Lee, and J. N. Hwang, “A novel rate predictor based on quantized DCT indexes and its rate control mechanism,” Signal Process.: Image Commun., vol. 18, pp. 427-441, Jul. 2003.
34 T. Chiang and Y.-Q. Zhang, “A new rate control scheme using quadratic rate distor-tion model,” IEEE Trans. Circuits Syst. Video Technol., vol. 7, pp. 246-250, Feb. 1997.
35 L. J. Lin and A. Ortega, “Bit-rate control using piecewise approximated rate-distortion characteristics,” IEEE Trans. Circuits Syst. Video Technol., vol. 8, pp. 446-459, Aug. 1998.
36 J. Bai, Q. Liao, X. Lin, and X. Zhuang, “Rate-distortion model based rate control for real-time VBR video coding and low-delay communications,” Signal Process.: Image Commun., vol. 17, pp. 187-199, Feb. 2002.
37 T. Chiang, and Y. Q. Zhang, “A new rate control scheme using quadratic rate distor-tion model,” IEEE Trans. Circuits Syst. Video Technol., vol. 7, pp. 246-250, Feb. 1997.
38 Z. He and S. K. Mitra, “Optimum bit allocation and accurate rate control for video coding via ρ-domain source modeling,” IEEE Trans. Circuits Syst. Video Technol., vol. 12, pp. 840-849, Oct. 2002.
39 D. K. Kwon, M. Y. Shen, C. C. J. Kuo, “Rate control for H.264 video with enhanced rate and distortion models,” IEEE Trans. Circuits and Syst. Video Technol., vol. 17, pp. 517-529, May 2007.
40 S. Ma, W, Gao, and Y. Lu, “Rate-distortion analysis for H.264/AVC video coding and its application to rate control,” IEEE Trans. Circuits and Syst. Video Technol., vol. 15, pp. 1533-1544, Dec. 2005.
41 N. Kamaci, Y. Altunbasak, and R. M. Mersereau, “Frame bit allocation for the H.264/AVC video coder via Cauchy-density-based rate and distortion models,” IEEE Trans. Circuits and Syst. Video Technol., vol. 15, pp. 994-1006, Aug. 2005.
42 Y. K. Tu, J. F. Yang, and M. T. Sun, “Efficient rate-distortion estimation for H.264/AVC coders,” IEEE Trans. Circuits and Syst. Video Technol., vol. 16, no. 5, pp. 600-611, May 2006.
43 M. G. Sarwer and L. M. Po, “Bit rate estimation for cost function decision of 4x4 intra mode decision H.264/AVC,” in Proc. IEEE Int. Conf. on Multimedia and Expo. (ICME’07), Jul. 2007, pp. 1579-1582.
44 M. G. Sarwer and L. M. Po, “Fast bit rate estimation for mode decision of H.264/AVC,” IEEE Trans. Circuits and Syst. Video Technol., vol. 17, pp. 1402-1407, Oct. 2007.
45 Q. Chen and Y. He, “A fast bits estimation method for rate-distortion optimization in H.264/AVC,” in Proc. Picture Coding Symp (PCS’04), San Francisco, CA, Dec. 2004, pp. 133-134.
46 Y. K. Tu, J. F. Yang, and M. T. Sun, “Efficient rate-distortion modeling for efficient H.264/AVC encoding,” IEEE Trans. Circuits and Syst. Video Technol., vol. 17, pp. 530-543, May 2007.
47 Y. C. Wei, and J. F. Yang, “Transformed-domain intra mode decision in H.264/AVC encoder,” in Proc. IEEE TENCON, Hong Kong, Nov 2006 , pp. 1-4.
48 T. Qian, J. Sun. D. Li, X. Yang, and J. Wang, “Transform domain transcoding from MPEG-2 to H.264 with interpolation drift-error compenstaion,” IEEE Trans. Circuits and Syst. Video Technol., vol. 16, pp. 523-534, Apr. 2006.
49 G. Shen, Y. He, W Cao, and S Li, “Complexity scalable MPEG-2 to WMV transcoder with adaptive error compensation,” in Proc. IEEE Int. Symp. on Circuits and Syst., Greece, May 2006, pp. 1711-1714.
50 A. Graham, ”Kronecker products and matrix calculus with applications,” Halsted Press, John Wiley and Sons, NY, 1981.
51 H. Everett, III, “Generalized lagrange multiplier method for solving problems of op-timum allocation of resources”, Oper. Res., vol. 11, pp. 399-417, 1963.
52 T. Wiegand and B. Girod, “Lagrangian multiplier selection in hybrid video coder con-trol,” in Proc. IEEE Int. Conf. Image Process (ICIP’01), Thessaloniki, Greece, vol. 3. Oct. 2001, pp. 542-545.
53 Y. Linde, A. Buzo, and R. Gray, “An algorithm for vector quantizer design,” IEEE Trans. on Commun., vol. 28, pp. 84-95, Jan. 1980.
54 Joint Video Team (JVT) Reference Software [Online]. Available: http://bs.hhi.de/~suehring/tml/download/
55 G. Bjontegaard, “Calculation of average PSNR differences between RD-curves,” in Proc. 13th Meeting ITU-T Q.6/SG16 VCEG, document VCEG-M33.doc, Austin, TX, Apr. 2001.
56 Advanced Video Coding for Generic Audiovisual Services, ITU-T Rec. H.264 and ISO/IEC 14496-10 (MPEG-4 AVC), ITU-T and ISO/IEC JTC 1, Version 1: May 2003, Version 2: May 2004, Version 3: Mar. 2005, Version 4: Sept. 2005, Version 5 and Ver-sion 6: June 2006, Version 7: Apr. 2007, Version 8 (including SVC extension): Con-sented in July 2007.
57 H. Schwarz, D. Marpe, and T. Wiegand, “Overview of the scalable video coding ex-tension of the H.264/AVC standard,” IEEE Trans. Circuits and Syst. Video Technol., vol. 17, pp. 1103-1120, Sep. 2007.
58 S. T. Wei, S. R. Shen, B. D. Liu, and J. F. Yang, “Lossless image and video coding based on H.264/AVC intra predictions with simplified interpolations,” in Proc. IEEE Int. Conf. Image Process (ICIP’09), Cairo, Egypt, Nov. 2009, pp. 633-636.