近年來由於視訊應用越來越普遍，在網路上分享視訊逐漸成為日常生活中不可或缺的一部分。然而，數位內容極易被竄改與複製，因此，保護數位內容已成為重要的議題。目前，針對H.264的浮水印文章日漸增多，其中以將浮水印嵌入AC係數之作法為最多。當浮水印嵌入後多多少少會造成的影像品質影響，甚少實際去探討如何減少對影像品質的影響。
本論文利用連續兩張畫面間模式運動估計求得之SAD (Sum of Absolute Differences)比值以進行場景切換之偵測。當偵測到場景切換畫面時，我們在下一個畫面不進行藏入浮水印動作，避免畫面品質更差，也避免不好的畫面品質蔓延到其他Frame中。
實驗結果顯示，相較於其他相關的演算法，我們所提出的演算法有較好的效能表現。

Digital video is an important part in our daily life. For example it’s more popular to share videos through the internet. At the same, it’s also easy to modify or copy digital videos in the internet. Therefore, how to protect the copyright of digital videos is an important topic today.
Recently, there are a lot of articles to introduce H. 264, a kind of watermark skill. In these articles, to embed watermark into AC coefficients is common methodology, but it will decrease the quality of digital videos. However, the problem is seldom been mentioned or discussed the solution how to reduce the impact in there articles.
In this paper, I propose to use the SAD (Sum of Absolute Differences) ratio of consecutive two frames to detect the scene change. When the scene change is detected, we don’t embed the watermark in next frame to avoid the quality of frame getting worse and to avoid making harmful influence on other frames.
The experimental results show that our proposed algorithm achieves better coding performance than other distinct algorithm.

[1] 李國光，Chung-Ping Liu, Pao-Chi Chang, “The Data Hiding Techniques for H.264 Video Coding Standard”，元智大學電機工程研究所碩士論文，中壢，2005。
[2] 林宜隆，陳聰毅，基於DCT 子影像之高不可視性H.264 抗壓縮浮水印，國立高雄應用科技大學電子工程系碩士論文，高雄，2009。
[3] 謝俊彥，張隆紋，基於頻率權重的H.264高容量浮水印技術，國立清華大學資工系碩士論文，新竹，2006。
[4] G. Qiu, P. Marzilian, A. T. S. Ho, D. He, and Q. Sun,“A Hybrid Watermarking Scheme for H.264 Video”, Processing of the 17th International Conference on Pattern Recognition, ICPR, Cambridge, UK, vol.4, pp.865-868, Aug 2004.
[5] 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.
[6] “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
[7] “Advanced video coding for generic audiovisual services”(ITU-T Rec. H.264| ISO/IEC 144496-10 AVC), Joint Video Team of ISO/IEC and ITU-T, Mar. 2005.
[8] I.J. Cox, J. Kilian, T. Leighton and T. Shamoon, “Secure Spread Spectrum Watermarking for Multimedia,” IEEE Trans. on Image Processing, pp. 1673-1687, 1997.
[9] Multimedia Messaging Service(MMS); Media Formats and Codecs,3GPP Technical Specification 3GPP TS 26.140, Dec. 2002.

[10] 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.
[11] Chien-Chang Chen and De-Sheng Kao, “DCT-based Zero Replacement Reversible Image Watermarking Approach”, International Journal of Innovative Computing Information and Control, vol.4, no.11, pp.3027-3036, Nov 2008.
[12] 詹晨鋒，張寶基，適用於場景切換之強健型H.264/AVC位元率控制，國立中央大學通訊工程學系碩士論文，中壢，2012。
[13] X. Jing, L. P. Chau, and W.C. Siu, “Frame Complexity-Based Rate-Quantization Model for H.264/AVC Intra frame Rate Control,” IEEE SIGNAL PROCESSING LETTERS, vol.15, pp. 373–376, 2008.
[14] Z. G. Li, F. Pan, and K. P. Lim, Adaptive Basic Unit Layer Rate Control for JVT, JVT-G012, 7th Meeting, Thailand, 2003.
[15] 施彥守，張隆紋，藏於量化後之離散餘弦轉換係數於H.264/AVC 的浮水印技術，國立清華大學資工系碩士論文，新竹，2007。
[16] Noorkami, Maneli; Mersereau, Russell M. ”Towards robust compressed-domain video watermarking for H.264”, Security, Steganography, and Watermarking of Multimedia Contents VIII. Edited by Delp, Edward J., III; Wong, Ping Wah. Proceedings of the SPIE, Volume 6072, pp. 489-497, 2006.
[17] Jing Zhang and Anthony T. S. Ho, “Robust digital image-in-video watermarking for the emerging H.264/AVC standard”, 2005 IEEE Conference, pp.657-662 , 2005.
[18] Zhang J, Ho A. T. S, Qiu G. and Marziliano, “Roubust video watermarking of H.264/AVC”, IEEE trans. On Circuits and Systems, part II, vol.54, issue 2, pp.205-209, Feb 2007.
[19] G. Bjontegaard, “Calculation of average PSNR differences between RD-curves,” ITU-T Q. 6/16, Doc. VCEG-M33, Apr. 2001.