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.
