An H.264 Video Watermarking Scheme Based On Motion Vector And Drift Compensation

The development of computer network communication technology and the increasing variety of digital products promote the wide dissemination of digital works. Although this process is helpful to the digital industry, unauthorized users can easily have access to, copy and distribute digital products due to the quality of products not declining after being copied, which greatly hinders the healthy development of the digital industry. Digital watermarking technology is able to embed copyright information without affecting the original data and the information cannot be easily removed, so that watermarking technology can identify the illegal copying and piracy of digital products, ensure the dissemination of legitimate copies. That explains why the digital watermarking technology is one of the effective methods for the copyright protection of digital products. Copyright protection of compressed domain video is still not well developed, which makes researches on such video digital watermarking technology more urgent. Therefore, multimedia digital video watermarking technology is the focus of research on information security.This paper focuses on the algorithms and theory of digital video watermarking, systematically reviews the development, classification, performance requirements and current situation of digital video watermarking and analyzes the key technology of digital video watermarking system. Currently, in the field of compressed domain video watermarking, algorithms taking motion vector as a watermark carrier spring up one after another, but few of these studies take robustness of the watermark into consideration. How to design a watermarking algorithm based on motion vector to resist the attacks is one of the difficulties in the field of video watermarking. After the study of H.264 coding standard and the existing algorithms, this paper proposes a H.264/AVC robust video watermarking algorithms based on motion vector and an algorithm to improving the visual impact of the drift compensation algorithm.This paper presents a robust H.264/AVC video watermarking algorithm based on motion vector. First, Arnold transform is performed on the watermark image to improve the security of the watermark information. In the process of watermark embedding location, horizontal motion vector residuals in the lower right corner of the smallest sub-block are used to embed copyright information. The selection may theoretically cause the least visual impact. Finally, discrete cosine transform is performed on the motion vector groups to utilize its energy concentration effect and obtain robustness against the lossy compression attacks. Experiments show that the algorithm has a strong invisibility considering visual impact and objective evaluation results. Watermarked video bit rate increases by 0.09% on average. Watermark detection correction rate is still able to achieve an average of 79% and at least 90% under the lossy compression attack and the motion estimation attack respectively. So the watermarking algorithm is robust against kinds of attacks.Because of the adverse effects on the video quality to the previous algorithm produced by the inter prediction in video coding, this paper has proposed a drift compensation algorithm to avoid watermarking distortion. By modifying the macroblock motion vector residuals which may be affected watermarking, video quality is improved without increasing the time of watermarking. Experiments show that the drift compensation algorithm not only has a low algorithmic complexity and the high real-time, but also improves the previous algorithm in terms of visual perception. Meanwhile, the video bit rate is rarely affected.