H.264是一個新興的視訊壓縮標準，現今不論是在有線或無線網路的視訊應用上，都相當受到歡迎。然而數位內容容易被消費者修改或是拷貝，因此著作權保護、拷貝控制和完整驗證，在近幾年已變成一個重要的議題。浮水印即是一種要求數位資料所有權的保護方法。
本論文中我們利用區塊極性與序號調變來達到浮水印的嵌入，其中區塊極性是由4x4 DCT轉換且量化後的DC係數來決定，而區塊序號則是由4x4 DCT轉換且量化後，其所有AC係數量級的總和來決定。區塊序號的最低位元被當成調變參數，藉由修改量化之AC係數來改變調變參數，進而達到嵌入浮水印的目的。為了抵抗時軸同步攻擊，像是畫面刪除，畫面插入或是畫面順序調換，我們亦提出基於特徵統計的時軸同步機制，特徵統計量是經由統計視訊內容中的局部變異量或是特徵空間分佈的投影量而得到，同時將其當作額外資訊傳送到浮水印萃取端。在浮水印萃取端，藉由比對額外資訊與從接收視訊中取出的特徵統計量，來達到時軸同步。
模擬結果顯示提出的浮水印系統有良好的效能，而且萃取浮水印不需要原始視訊，同時浮水印演算法有較低的複雜度，可適合即時性的應用；而基於特徵統計的時軸同步機制，可促使浮水印系統更有效的抵抗時軸同步攻擊。

H.264 is a new advanced standard. The applications of video on Internet or wireless networks become very popular nowadays. However, these digital contents can be easily modified and copied by end users. Hence copyright protection, copy control and integrity verification has become important issues in recent years. Digital watermarking is a means of claiming ownership of a data source.
In the proposed system, block polarity and block index modulation are used to achieve watermark embedding. The block polarity is determined based on the nonzero quantized DC coefficient in each 4x4 integer DCT block. The block index is the pseudo-quantized block activity that is represented by the sum of magnitude of quantized AC coefficients. The watermark embedding is actually performed by the index modulation that will modify quantized AC coefficient values by a small amount to force the activity to be quantized into a specific region.
For resisting temporal attacks, such as frame dropping, frame insertion, and frame transposition, we also propose a temporal synchronization method for video watermarking by matching feature statistics. The feature statistics are calculated by local variances or eigenvalues in video content and sent as side information. Temporal attacks can be detected by comparing side information and feature statistics that be calculated from the received video.
Simulation results show that the proposed method performs well and extract embedded watermark without the original video signal. Additionally, the algorithm is not very complex and appropriate for real-time applications. Based on the extracted feature statistics, the video watermarking system is more robustness against temporal attacks.

參考文獻
[1]T. Wiegand, G. J. Sullian, G. Bjontegaard, and A. Luthra, “Overview of the H.264/AVC Video Coding Standard,” IEEE Trans. Circuits System Video Technology, vol. 13, pp. 560-576, July 2003.
[2]“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
[3]Multimedia Messaging Service(MMS); Media Formats and Codecs, 3GPP Technical Specification 3GPP TS 26.140, Dec. 2002.
[4]T. Kimura and K. Asai, “Technologies for Image Applications on Mobile Phone,” Information Technology R&D Center. Mitsubishi Electric Advance TECHNICAL REPORTS, vol. 11, pp.11-14, Jun. 2005.
[5]T. Stockhammer, M. Hannuksela, and T. Wiegand, “H.264/AVC in Wireless Environments,” IEEE Trans. Circuits System Video Technology, vol.13, pp. 657-673, July 2003.
[6]S. Wenger, “H.264/AVC over IP,” IEEE Trans. Circuits System Video Technology, vol. 13, pp. 645-656, July 2003.
[7]T. T. Lu and P. C. Chang, “ Selective Weighting on Wavelet Coefficients for Blind Image Watermarking System,” SPIE Conf. Optics & Photonics 2005 Symposium, vol. 5915, pp. 201-208, San Diego, CA., 2005.
[8]C. I. Podilchuk and E. J. Delp, “Digital watermarking: algorithms and applications,” IEEE Signal Processing Magazine, vol. 18, no. 4, pp. 33-46, July 2001.
[9]G. Dorr and J. L. Dugelay, “A guide tour of video watermarking,” Signal Process. Image Commun., vol. 18, no. 4, pp. 263-282, Apr. 2003.
[10]Y. Bodo, N. Laurent, C. Laurent, and J. L. Dugelay, “Video waterscrambling: towards a video protection scheme based on the disturbance of motion vectors,” EURASIP Journal of Applied Signal Processing special issue : Multimedia Security and Rights Management, vol. 2004, issue 14, pp. 2224-2237, Oct. 2004.
[11]J. Lee and C. S. Won, “Authentication and correction of digital watermarking images,” Electronics Letters, vol. 35, no. 11, pp. 886-887, May 1999.
[12]M. Barni, F. Bartolini, R. Caldelli, V. Cappellini, A. D. Rosa, and A. Piva, “Robust frame-based watermarking for digital video,” 12th International Workshop on Database and Expert Systems Applications, pp. 825-829, 2001.
[13]J. Huang and Y. Q. Shi, “Adaptive image watermarking scheme based on visual masking,” Electronics Letters, vol. 34, no. 8, pp. 748-750, April 1998.
[14]Z. H. Wei, P. Qin and Y. Q. Fu, “Perceptual digital watermark of images using Wavelet transform,” IEEE Transactions on Consumer Electronics, vol. 44, no. 4, pp. 1267-1272, Nov. 1998.
[15]C. T. Hsu and J. L. Wu, “DCT-based watermarking for video,” IEEE Transactions on Consumer Electronics, vol. 44, no. 1, pp. 206-216, Feb. 1998.
[16]R. B. Wolfgang, C. I. Podilchuk and E. J. Delp, “Perceptual watermarks for digital images and video,” Proceedings of the IEEE, vol. 87, no. 7, pp. 1108 -1126, July 1999.
[17]I. J. Cox, J. Kilian, F. T. Leighton and T. Shamoon, “Secure spread spectrum watermarking for multimedia,” IEEE Transactions on Image Processing, vol. 6, no. 12, pp. 1673 -1687, Dec. 1997.
[18]F. Hartung and B. Girod, “Digital watermarking of uncompressed and uncompressed video,” Signal Processing, vol. 66, no. 3, pp. 283-301, 1998.
[19]I. J. Cox, M. Miller, and J. Bloom, Digital Watermarking, Morgan Kaufmann Publishers, Los Altos, CA, 2001 ISBN 1-55860-714-5
[20]E. T. Lin and E. J. Delp, “Temporal Synchronization in Video Watermarking,” Proceedings of the SPIE International Conference on Security and Watermarking of Multimedia Contents IV, vol. 4675, San Jose, CA, pp.478-490, Jan. 2002.
[21]F. A. P. Petitcolas, R. J. Anderson, and M. G. Kuhn, “Attacks on copyright marking systems,” in Information Hiding: 2nd Int. Workshop (Lecture Notes in Computer Science), vol. 1525, D. Aucsmith, Ed. Berlin, Germany: Springer-Verlag, pp. 218-238, 1998.
[22]Stirmark Benchmark 4.0 is available on http://www.petitcolas.net/fabien/watermarking/stirmark/
[23]S. Pereira, S. Voloshynovskiy, M. Madueno, S. Marchand-Maillet and T. Pun, “Second generation benchmarking and application oriented evaluation,” in Information Hiding Workshop III, Pittsburgh, PA, USA, Apr. 2001.
[24]Official Optimark Page: http://poseidon.csd.auth.gr/optimark/
[25]S. J. Weng, T. T. Lu, and P. C. Chang, “Key-based video watermarking system on MPEG-2,” in SPIE Conf. Electronic Imaging 2003, vol. 5020, pp. 516-525, Santa Clara, CA, Jan. 2003.
[26]Y. Dai, L. Zhang, and Y. Yang, “A new method of MPEG video watermarking technology,” International Conference on Communication Technology Proceedings, ICCT 2003, vol. 2, pp. 1845-1847, Apr. 2003.
[27]B. G. Mobasseri and M. P. Marcinak, “Watermarking of MPEG-2 video in compressed domain using VLC mapping,” Proceedings of the 7th workshop on Multimedia and security, pp. 91-94, Aug. 2005.
[28]M. Noorkami, and R. M. Mersereau, “Compressed-Domain Video Watermarking for H.264,” IEEE International Conference on Image Processing, ICIP, vol. 2, pp. 890-893, Sept. 2005.
[29]G. Qiu, P. Marzilian, A. T. S. Ho, D. He, and Q. Sun, “A Hybrid Watermarking Scheme for H.264 Video,” Proceedings of the 17th International Conference on Pattern Recognition, ICPR, vol. 4, pp. 865-868, Aug. 2004.
[30]K. Su, D. Kundur, and D. Hatzinakos, “Statistical Invisibility for Collusion-resistant Digital Video Watermarking,” IEEE Transactions on Multimedia, vol. 7, no. 1, pp. 43-51, Feb. 2005.
[31]P. Bas, J. M. Chassery, and B. Macq, “Geometrically Invariant Watermarking Using Feature Points,” IEEE Trans. On Image Processing, vol. 11, no. 9, pp. 1014-1028, Sep. 2002.
[32]E. T. Lin, and E. J. Delp, “Temporal Synchronization in Video Watermarking,” IEEE Transactions on Signal Processing, vol. 52, pp. 3007-3022, Oct. 2004.
[33]J. Wang, and J. C. L. Liu, “Content-Based Block Watermarking Against Cumulative and Temporal Attack,” IEEE International Conference on Multimedia and Expo, ICME, pp. 77-80, Jul. 2005.
[34]S.W. Sun, and P.C. Chang, “Video Watermarking Synchronization Based on Profile Statistics,” IEEE Aerospace and Electronic Systems Magazine, vol.19, no. 5, pp. 21-25, May 2004.
[35]I. E. G. Richardson, H.264 and MPEG-4 Video Compression: Video Coding for Next-generation Multimedia, John Wiley & Sons Ltd Publishers, 2003, ISBN 0-470-84837-5.
[36]T. T. Lu, W. L. Hsu, and P. C. Chang, “Blind Video Watermarking for H.264,” in Proc. IEEE Canadian Conference on Electrical and Computer Engineering (CCECE 2006), pp. 2318-2321, Ottawa, Canada, May 2006.
[37]K. W. Liang, T. T. Lu, and P. C. Chang, “Image Authentication System based on Eigenvalue Decomposition,” in Proc. IPPR Conf. on CVGIP 2005, pp. 1331-1336, Taipei, Taiwan, Aug. 2005.