在這篇論文當中，我們針對H.264探勘其動作估測複雜度的可伸縮性。我們提出的模型利用馬可夫鏈的模型把前一張畫框的MB與現在這張畫框相同位置的MB的關係串連起來並且用之來做預測。馬可夫鏈模型包含一種轉移機率矩陣可以用來表明MB在前面幾張畫框的樣式機率。馬可夫鏈也包含了一種決策矩陣，這個決策矩陣由二元元素所構成，其中1代表打開樣式而0代表關閉樣式。經由這個模型，我們可以建立一組限制式，而其中的最佳解則代表我們所做出來的最佳樣式決策。

為了要確使這個模型適用於實際操作，我們必須先針對模型做簡化。所以決策矩陣必須被修改，我們首先降低決策矩陣裡面的元素，而此時所有決策矩陣裡面的元素並不再都是二元的。因此如果我們利用複雜程度因子x來限制目標的複雜度，我們可以藉由限制式的最佳解來做在該複雜程度的最佳樣式決策。實驗結果顯示出我們提出的這個演算法不但可以妥善的利用複雜度，更可以有效的控制動作估測需要的時間。而我們提出來的這個畫框間預測模式之可伸縮決策模型更同時可以在允許的性能下降範圍當中，讓運動估測的時間變得更有彈性。

In this thesis, the complexity scalability for H.264 motion estimation is to be explored. The model proposed uses Markov Chain Model to relate the prediction modes of the MB in the previous frame to that of the MB at the same position in the present frame. The Markov Chain Model includes a transition probability matrix which indicates the mode probability of MBs in the previous frames. The Markov Chain Model also includes a decision matrix which is composed of binary elements and 1 means the mode on while 0 means the mode off. In this way, we can build a set of constraint equations that the optimal solution represents the optimal mode decision.

In order to make the problem practical, model simplification is executed. The decision matrix is modified and not all of elements in the decision matrix are binary. Hence, if we restrict the target complexity by a restricted complexity level, x, we can get the optimal mode decision at such complexity level. The experimental result shows that the proposed algorithm can not only utilize the target complexity well, but also control the motion estimation time well. Together with the proposed scalable inter-mode decision model we can make the motion estimation time more flexible with acceptable performance degradation.

[1] Information Technology Coding of Audio-Visual Objects Part 10: Advanced Video Coding. Final Draft International Standard, ISO/IEC FDIS 14 496-10.

[2] T. Wiegand, G.J. Sullivan, G. Bjntegaard, and A. Luthra, "Overview of the H.264/AVC video coding standard", IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECNOLOGY, VOL, 13, NO.7 JULY 2003.

[3] Minhua Zhou, "Evaluation and Simplification of H.26L Baseline Coding Tools", ITU-T Q.6/16, Doc.#JVT-B030, 2002.

[4] I. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. Cayirci, “A survey on sensor networks,” IEEE Commun. Mag., pp. 102–114, Aug. 2002.

[5] P. Agrawal, J.-C. Chen, S. Kishore, P. Ramanathan, and K. Sivalingam, “Battery power sensitive video processing in wireless networks,” in Proc. IEEE PIMRC’98, vol. 1, Boston, MA, Sep. 1998, p. 116.

[6] X. Lu, Y. Wang, and E. Erkip, “Power efficient H.263 video transmission over wireless channels,” in Proc. 2002 Int. Conf. Image Processing, Rochester, NY, Sep. 2002, pp. 533–536.

[7] Zhihai He, Yongfang Liang, Lulin Chen, Ahmad I., Dapeng Wu, “Power-rate-distortion analysis for wireless video communication under energy constrains,” IEEE Trans. Circuits Syst. Video Technol., vol. 15, Issue 5, pp. 645–658, May 2005.

[8] Yongfang Liang, Ahmad I., “Power and content aware video encoding for video communication over wireless network,” Signal Processing Systems, 2004. SIPS 2004. IEEE Workshop on 2004. pp. 269–274.

[9] H. S. Malvar, A. Hallapuro, and M. Karzewicz, “Low-complexity transform and quantization in H.264/AVC,” IEEE Trans. Circuits Syst. Video Technol., vol. 13, no. 7, pp. 598–603, Jul. 2003.

[10] ISO/IEC MPEG and ITU-T VCEG Joint Video Team, JVT-K049, Joint Model Reference Encoding Methods and Decoding Concealment Methods, 2004.

[11] H. Chung, D. Romacho, and A. Ortega, “Fast long-term motion estimation for H.264 using multiresolution search,” in Proc. IEEE Int. Conf. Image Process., Barcelona, Spain, 2003, pp. 905–908.

[12] J. Stottrup-Andersen, S. Forchhammer, and S. M. Aghito, “Rate-distortion- complexity optimization of fast motion estimation in H.264/MPEG-4 AVC,” in Proc. IEEE Int. Conf. Image Process., Singapore, Oct. 2004, pp. 119–122.

[13] JVT-J033, Fast Mode Decision for H.264, Dec. 2003.

[14] P. Yin, H. Y. Cheong, A. M. Tourapis, and J. Boyce, "Fast mode decision and motion estimation for JVT/H.264," in Proc. IEEE ICIP, vol. 3, Sep. 2003, pp.853-856.

[15] Wu, D., Pan, F., Lim, K.P., Wu, S., Li, Z.G., Lin, X. et al. "Fast Inter mode Decision in H.264/AVC Video Coding", IEEE Transations on Circuits and Systems for Video Technology, vol. 15, pp.953-958, July.2005.

[16] C.W. Ting, L.M. Po, and C.H. Cheung, "Center-biased frame selection algorithms for fast multi-frame motion estimation in H.264," Proceeding of 2003 IEEE International Conference on Neural Networks and Signal Processing, pp. 1258-1261, Dec. 2003.

[17] Spinsante S., Chiaraluce F., Gambi E., Falasconi C., “Mode decision optimization issues in H.264 video coding,” Signal Processing and Information Technology, 2005. Processings of the Fifth IEEE International Symposium on Dec. 18–21, 2005 pp. 624–629.

[18] Bin Feng, Guang-xi Zhu, Wen-yu Liu, “Complexity scalable inter mode decision algorithm for H.264 based on spatial correlation,” Advanced Communication Technology, 2006. ICACT 2006. The 8th International Conference Volume 2, pp.963-966, Feb. 2006.

[19] Ming Yin, Hong-Yuan Wang, “An improvement fast INTER mode selection for H.264 joint with spatio-temporal correlation,” Wireless Communications, Networking and Mobile Computing, 2005. Proceedings. 2005 International Conference on Volume 2, pp. 1237-1240, Sept. 2005.