Based On Ldpc Block Mean Video Watermarking Algorithm Research Of Ofdm Technology

The development of the network technology and the increasing popularity of digital TV, make it easy to watch, copy and transfer digital multimedia products, and make our life more colorful, but they also cause some safety problems to digital video, such as the copyright protection, piracy tracking, play control, etc. The traditional cryptography technology can not fully protect the safety of the video any more, and then the video watermarking technology arises at the historic moment and becomes the hot research area.Based on the needs of Northwest University-Irdeto Information Security Joint Laboratory, this paper proposes a block-mean video watermarking algorithm based on LDPC-OFDM technology. This algorithm analyses the communication system and watermarking model, according to the similarity of them, use the LDPC and OFDM communication technology to the watermark preprocessing procedure. It effectively improved the error correction ability of the watermark, and also improved the ability to against geometric distortion. The procedures of this algorithm are as follows:firstly, preprocess the watermark with LDPC-OFDM technologies, then embed it in the R value of the chrominance component, this can ensure the invisibility of the watermark and make it able to against attack. At the same time, make repeated coding of the frame numbers, and embed them in the G value of the chrominance component. This algorithm can realize copyright protection, piracy tracking and play control because the algorithm can embed watermark in spatial domain and extract it in spatial domain or compressed domain. Experimental results show that the proposed algorithm almost have no impact to the video, the video can ensure good video quality. The watermark can be extracted blindly and it’s robust to geometric distortion such as shear attack. Also the algorithm can resist video conventional processing, such as gaussian low-pass filter, gaussian white noise, salt and pepper noise and MPEG-2compression. For simple synchronous attacks the algorithm also has certain ability to resist. It’s really a blind video watermarking algorithm with low complexity and good performance.