Watermarking Algorithm In H.264Compressed Domain

Recently, with the popularization of computer and maturing of network technology, video technology has got rapid development, and it has brought big convenience to people. Meanwhile, safety awareness of people is improving, so people pay more attention on the issue of video copyright protection. The video watermark technology is playing a big role on copyright protection and becomes an important tool. H.264which is a new generation video coding standard has advantages of high compression ratio and wide application, especially it can provide high quality video service in low bitrate. Therefore, research on video watermarking algorithm based on H.264is of great significance. In this paper, tow kinds of algorithm based on H.264are proposed.The main work is summarized bellow.Firstly, watermarking algorithm based on region of low perception was proposed. This proposed method built the module of visual perception based on analyzing the luma contrast information and motion information of the images, and extracted the region of low perception. Watermark information was embedded in the macroblock which was in the region of low perception.The proposed method modulated the two parts of energy:one part the energy was the last sub4×4block in the certain macro-block, and the other was the average energy of the other15sub4×4block. By means of modulating the energy difference of the tow parts, the watermark information could be embedded. In order to guarantee the image quality, energy difference threshold was divided into some average parts. In this way, change of energy was restricted into a certain range.Secondly, on the basis of the texture features of the pictures, this algorithm embedded watermarking information on the DCT domain of IDR frames. First, a rectangular sliding window was used to search the region of complex textures. Second, In the selected region, a sub4×4block of maximum energy was chosen for embedding one watermarking bit. Last, one AC coefficient value of the selected sub 4×4block was modified adaptively. Experimental results show that the algorithm can effectively resist the re-coded attacks, the changes of the peak signal noise ratio and the bit rate are very small.Finally, after the conclusion of this issue, this paper simply prospected the future direction of video watermarking.