A Research On Video Watermarking Based On H.264Standard

With the rapid development of digital multimedia and Internet technologies, the publication and transmission of digital media have become simpler and faster. Due to the simplicity of tampering and the rapidity of spreading, digital media publishers and service providers are subjected to copyright crisis, which directly harms the digital media industry. Thus, copyright protection technology has attracted more and more attention through the past decades. As a powerful and effective tool of copyright protection technology, video watermarking has become one of the central issues of information security.Digital video watermarking technology is developed on the basis of digital image watermark algorithms. At first, video watermarking algorithms regard the video as a sequence of consequent images. The watermark is directly embedded into the sequence of images which haven’t been encoded, and then the images containing the watermark information are encoded into video streams according to certain compression standards. This kind of algorithms could take advantage of image watermarking schemes which are relatively more mature, and could utilize theories such as Spread Spectrum, and HVS (Human Visual System). But the schemes of this kind have obvious disadvantages:the compressed video need to be decoded first, then the watermark is embedded, and at last, the video is re-encoded. This increases the complexity of the calculation, and makes the schemes difficult to achieve real-time requirements. To be a real-time algorithm, the watermark should be embedded directly into the video compression bit stream. The most commonly used video compression standard is H.264, which is a block-based scheme and uses inter and intra prediction to deduce the redundancy of video frames. Embedding directly in compression bit stream could make full use of the prediction which has been done in the previous encoding procedure, and could well meet the real-time requirement. In this paper, a video watermarking algorithm framework is proposed based on H.264standard and the following watermarking algorithms are designed in this framework.Starting from the basic concepts of digital watermarking, the basic principles and the performance requirements of digital watermarking technology are introduced. Then, the characteristics and relationship of digital video and image watermarking technology is analyzed. Next, conventional video watermarking technology is briefly introduced, according to two classifications, and the advantages and weaknesses of each type are indicated. Based on these topics, a digital image watermarking algorithm based on non-correlation detection on the relative relationship of DCT coefficients, and a removable digital video watermarking algorithm based on the correlation detection in DCT domain, are proposed. After introduced the principle and implementation of these two algorithms, we’ve evaluated their performance. Finally, two digital video watermarking algorithms are summarized, and the directions of future research and improvement are indicated.