A Video Watermarking Algorithm Research Based On HEVC

In the Internet era, digital video technology developed very rapidly, digital video has penetrated into every corner of people’s lives. However, the copyright owner has been plagued by copyright protection during the development of digital video technology. For this, the robust video watermarking technology is an easy and efficient solution to protect copyright. In addition, the reversible watermarking due to its characteristic of recovering host information without distortion will play an important role in some fields such as medical treatment and military which are very sensitive to distortion.In 2013, a new generation of video coding standard- High Efficiency Video Coding(HEVC) has been formally proposed,it has more higher coding efficiency than the ever coding standard and will be the major coding standard in the future.Therefore, the video watermarking technology research based on HEVC has very important practical significance. Base on this, a robust video watermarking algorithm for HEVC based on texture direction and a reversible watermarking algorithm for HEVC intra-frames without error propagation have been proposed, the main innovation points of this article could be concluded as following:Firstly, considering low robustness of existing video watermarking algorithms for HEVC, a robust video watermarking algorithm based on texture direction has been proposed in this paper. The intra-frame angular prediction modes were divided into horizontal direction modes and vertical direction modes, then the mapping was established between the two direction modes and watermarking value. During the intra-frame compressing coding, texture direction for each prediction unit was calculated when the splitting mode was N×N. Once the texture direction was consistent with the direction represented by watermarking value, the 33 angular prediction modes of current prediction unit would be truncated into the horizontal or vertical direction prediction modes, and a best prediction mode which could decide whether watermarking was embedded would be decided on the basis of rate distortion cost function. The location of embedded watermarking would be recorded as a keyfor extraction at decoding side. The experiment results show that the proposed algorithm has little impact on the video quality and bit rate, and can effectively resist the common attack such as the gauss noise, gauss filter and re-coded performed on the video watermarking.Secondly, in order to avert error propagation after embedding watermarking in I frames and recover the video content without distortion after extracting watermarking from watermarked video, a reversible video watermarking algorithm without error propagation has been proposed in this paper. This algorithm took intra-frame prediction coding process and error propagation after embedding watermarking in I frame into account, analyzed the conditions to avert error propagation after embedding watermarking. Appending on these proposed conditions, for each 4×4prediction unit in intra-frame, a determination has been done about whether meet all conditions. With all conditions satisfied, the quantized discrete sine transform coefficients of current 4×4 prediction unit was treated as carrier to embed watermarking, meanwhile, both the specific sign data hiding and coefficient scanning characteristics of HEVC was considered, then the method based on sum invariability was used to adaptively embed watermarking. For reducing the growth of bit rate, the block with all zero coefficients will be ignored. The results show that this algorithm can effectively eliminate the error propagation caused by watermarking embedded in I frame while keeping low bit rate increasing. And the video content can be recovered without distortion after extracting watermarking at decode side.