Research Of Video Digital Watermarking DCT Algorithm Based On MPEG-4

With great development of the IT and network technology, we easily have multimedia by Internet and CD-ROM, and these media are duplicates of original data. So as an effective method to provide copyright protection for digital media, digital watermarking has received considerable attention all over the world in recent years.Digital watermarking is an important branch of information hiding and a new digital products protection technology. It is a process of embedding a watermarking, such as author's copyright information or authentication information, into various digital products, such as images, audio, video or software etc. By this way, watermarking can distinguish the illegal copy and embezzlement of the digital products and protect intellectual property right. As MPEG-4 video standard is more and more used for applications such as video editing, network video communications, the MPEG-4 video data must have a copyright protection such as watermarking to protect the copyright.In this paper, applications of watermarking video content and main technical thoughts in video watermarking are studied. Two new and improved DCT(discrete cosine transformation) algorithms are put forward in this thesis for MPEG-4 video: Aimed at Uncompressed MPEG-4 domain, a new DCT watermarking algorithm is proposed based on Watson model. The embedded position is fixed on by Watson model. In order to encrypt the watermarking, the spread-spectrum is introduced. This scheme has strong robustness; An improved DCT-based digital watermarking technique is proposed in this article. Through analysis of MPEG standard, different watermarking schemes are given for intra-frames and non-intra-frames respectively. The whole method and its implementation are presented in detail. Several experimental results have demonstrated that the proposed watermarking algorithm is robust against some typical attacks in terms of geometric clipping and linear interpolation. It is hoped the proposed method can be effectively applied to Web2 based video applications.The major research works and innovatory points in this thesis are as follows:1. This paper firstly points out the important meaning of digital watermarking to the science research and industry production based on the background of problem studied, and analyzes the current status and developing trend of the digital watermarking. 2. The basic principles, features and problems of watermarking and MPEG-4 are summarized. The video watermarking is researched thoroughly.3. 1. A new discrete cosine transformation (DCT) watermarking algorithm is proposed based on Watson model. The embedded position is fixed on by Watson model. In order to encrypt the watermarking, the spread-spectrum is introduced. This scheme has strong robustness.4. Several algorithms for MPEG-4 watermarking are studied, such as Patrick Bas, Nikolaos, V.Boulgouris, Adnan M.Alattar[8]. A method for watermarking of MPEG-4 compressed video is presented. Spread spectrum technology is used to improve the security of watermark sequences. A synchronization template is used to combat geometrical distortion such as cropping, scaling, and rotation. Both signals, synchronization and watermark are embedded in the bit stream. A drift compensator is used to eliminate the distortion due to AC/DC prediction in I-VOPs and motion compensation in P-VOPs, to maintain robustness of the watermarking and the quality of the video, and resist format conversion attack. A bit stream control mechanism is introduced to main the data rate after the embedding manipulation. From the experiment results, it indicates that, after the watermarked MPEG-4 videos suffer filtering, rotation, scaling and transuding, the watermarking possesses good imperceptibility and robustness.5. The research direction and possible prospect of the digital watermarking for MPEG-4 video text document s are analyzed.