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As a main method for copyright protection of digital video data, video watermarking has been proposed and investigated. However, unlike still image, video watermarking technology must meet the real-time requirement. In this paper a new real-time watermarking, differential number watermarking (DNW), which can be directly performed in the VLC domain, will be proposed. The label bits are embedded in a pattern of number differences between two subregions by selectively removing high frequency components. The DNW algorithm has only half the complexity of other VLC domain watermarking algorithms. And comparing with the DEW algorithm, it doesn't need quantization step. The experimental results show that the DNW algorithm performs better on watermark's visual quality impact, capacity and robustness than the DEW algorithm.

As a main method for copyright protection, watermarking techniques have been widely studied and applied. The proposed algorithm splits the original image into blocks and classifies these blocks based on visual masking. Watermarking components with different strength are inserted into some DCT coefficients according to the classification. The experimental results demonstrate our algorithm is robust against noise and commonly used image processing techniques.

This paper proposes a multiple watermarking algorithm based on code division multiple access (CDMA) technique. Before the watermark embedded, each user uses his private key as a seed to generate an address code which is subjected to pseudorandom noise distribution. Each watermark is modulated into a carrier signal with its corresponding address code. And then these carrier signals are added to host media (e.g. image, video and audio). During watermark detection, using the same address code, each user extracts his watermark from the detected media via calculating the correlation coefficient between address code and watermarked vector of the detected media. Each user can embed and extract his watermark independently, regardless of others. The experimental results show that this scheme can embed and extract watermarks independently for each user and is capable for multiple watermarking.