# Anti-Recompression Video Watermarking Algorithm Based on H.264/AVC
## 1 Introduction  
Media technology and internet technology have provided great convenience for current video production and dissemination. However, the information security and copyright protection of video have also become prominent. Although digital watermarking technology can play a role in copyright protection, the current video watermarking algorithm has insufficient ability to resist re-compression. At present, video watermarking is mainly divided into two categories: digital video watermarking algorithm based on the original domain or compressed domain [1]. The video watermarking algorithm based on the original domain embeds and extracts the watermark in the original video sequence without compression coding. It can be divided into video watermarking algorithms based on the space domain [2; 3] or the transform domain [4; 5; 6; 7]. [PERSON] [2] et al. proposed a video watermarking algorithm in the space domain, which converts the original video frame from the original color space to HSV color space, and the watermark is embedded in a pair of coefficients in the HSV space. [PERSON] [4] et al. proposed a video watermarking algorithm based on pseudo 3D-DCT (three-dimensional cosine transform). The algorithm performs the pseudo 3D-DCT transform on the low frequency component of NSCT (nonsubsampled contourlet transform) of the key frame group, and the encryption watermark is embedded into the NMF (non-negative matrix factorization) decomposition of the DC coefficient matrix of the 3D-DCT transform, which is strongly robust. [PERSON] [5] et al. proposed a blind video watermarking algorithmbased on tensor decomposition, which uses the parity quantization of the maximum core tensor to realize the embedding and extraction of video watermarking. Video watermarking based on the compressed domain is embedded and extracted in the process of video encoding and decoding or in the compressed video stream. Common video compression standards include MPEG-X [8], H.264/ AVC [9; 10], H.265/ HEVC [11; 12] and 3D-HEVC [13; 14]. The video watermarking algorithm in H.264 encoding mode can be divided into three types: the video watermarking algorithm based on motion vector [15; 16]; DCT (discrete cosine transform) coefficient; and entropy encoded codeword. [PERSON] [15] et al. proposed a fragile video watermarking algorithm based on motion vector, extracted the feature code from the energy block of I frame, used the minimum Lagrange function search, and embedded the watermark in the motion vector with the best rate distortion performance in the macroblock with small segmentation mode. [PERSON] [16] et al. proposed a bit-watershed video watermarking algorithm based on moving target detection. The algorithm embeds the watermark in the level codeword after P-frame entropy coding. It is common to embed watermarking in DCT coefficients after video transform and coding. [PERSON] [17] et al. proposed a video watermarking algorithm based on chromaticity residual DCT, selected the subblock with the largest residual, and embedded the watermark by modulating the three coefficients. [PERSON] [18] et al. proposed a semi-fragile video watermarking algorithm that can achieve frame attack and video tamper detection at the same time. The frame number is used as the watermark information, and the relationship between non-zero DCT coefficients is used as the authentication code, and the watermark is embedded in subblocks with multiple non-zero coefficients. [PERSON] [19] et al. designed a cost function combining block distortion, bit rate change and block complexity to select texture regions and embed the watermark with minimum distortion. [PERSON] [20] et al. embedded the watermark into the DCT subblock by modulating the positive and negative coefficients of the watermark, and the algorithm can be applied to video sequences with different resolutions. [PERSON] [21] et al.