提出了一种基于直流分量的自适应视频水印算法。在对原始视频帧进行随机选择的基础上，对亮度分量作二维4×4整数变换，并提取直流分量分组进行一维整数变换；为了兼顾水印的不可见性与鲁棒性的要求，根据水印长度和变换之后系数的大小自适应地选择嵌入水印的组及系数的改变强度。水印嵌入之前进行随机置换与LDPC编码增强了水印抗攻击能力。实验结果表明,该算法能够保证很好的视频质量,视频帧的PSNR值高于50dB，并实现了水印的盲提取。对于常见的视频攻击有较强的鲁棒性，特别是在多种格式压缩的条件下能有效提取水印。

An adaptive video watermarking algorithm based on the DC Component is proposed in this paper. Based on the stochastically selected video frames, two dimensional 4by4 integer transform is performed on the luminance component, and then the DC coefficients are grouped to conduct one dimensional integer transform. To balance between the invisibility and robustness of watermarks, we utilize the length of the watermarks and the value of the transformed coefficients to adaptively select the groups to embed watermarks and the intensity of the coefficients modification. Watermarks are stochastically permuted and coded by LDPC to improve the robustness against attacks. Experimental results show that the proposed approach can achieve fine video quality and PSNR is higher than 50dB. Moreover, the watermarks can be extracted blindly and are robust to common video attacks. Especially, it can effectively extract watermarks under diverse compressions.