The Research And Implementation Of Video Watermark

With the rapid development of computer network and multimedia (digital images, video ,audio) technology, Multimedia knowledge copyright protection becomes an urgent problem to be solved. As one of the important means of multimedia copyright protection, the watermark technology of the video has got more and more extensive research.This paper introduces video concept, main apply domain, main characteristic, classification and technological difficult point of video watermark at first. And then analyze the MPEG-4 principle. After that the inevitability which video watermark technology and video frequency compression standard combined is discussed. Combining the compress standard of MPEG-4, this paper has discussed the choice question of watermark embedded domain in MPEG-4 and analyzed the existing video watermark algorithm based on DCT domain. Based which, a method of video watermark which is based on DCT domain in MPEG-4 is designed. And then this paper provides the design and implementation course of algorithm, and test result. In this method, watermark information is embedded directly in DC component in DCT domain of I-VOP after Arnold transform. There is no need of completely encoding and decoding. Therefore, it decreases the complexity of embedding algorithm and increases the real-time. This algorithm, which uses for reference of the idea of LSB algorithm, embeds the watermark information into the last position of the DC coefficient and greatly reduces the complexity of the watermark embedded algorithm. The watermark is retrieved not to need primitive video. The blind retrieving is achieved. In addition, the watermark has strong robust when the video frequency effect is not dropped, because the watermark is embedded in luminance DC domain.Experimental results show that video quality has not visible change between in front watermark embedded and at the back. And the watermark information compared with original watermark has not obvious change. In this method, the watermark is only embedded in I frame, not in P frame and B frame. This method is resisted the skip anddeletion of the frame in effect because the I frame is not skipped or deleted. And it has strong robust under the image processing attacks such as cutting, filter, sharping and yawp etc.