H.264/AVC压缩域鲁棒视频水印

Robust video watermarking in H.264/AVC compressed domain

针对现有H.264/AVC压缩域开环水印方法存在误差漂移及鲁棒性差的问题,分析了该类水印算法的特点及误差漂移机制,提出了一种无误差漂移的鲁棒视频水印算法。首先,基于视频重建过程,分析了开环回路水印方法的误差漂移机制,得到由水印信息造成的独立重建误差。然后,采用误差间的线性组合得到4个可以避免误差漂移的水印模板。最后,通过调制残差系数与相应水印模板之间的正负相关性,将水印嵌入在非零系数多的4×4子块上,而不像以往算法将水印直接添加在残差系数上。实验结果表明:所提算法造成的平均结构相似度下降在0.005以内;码率的增长在1.00%左右;对重量化转码、加性高斯白噪声、亮度调节等常见水印攻击,误码率均在0.15以下。得到的结果满足视频水印算法对透明性,码率稳定性,鲁棒性的要求。

To solve the error-drift problem and improve the robustness of state-of-the-art open-loop video watermarking algorithms performed in H.264/AVC compressed domain,the characteristics of error-drift of open-loop watermarking method was deeply investigated.A new robust video watermarking algorithm without error-drift was proposed.Firstly,the error-drift mechanism of the open-loop watermarking method was analyzed in detail to derive the independent reconstruction error of watermarking information during the process of video reconstruction.Then,four watermarking patterns enabling to avoid the error-drift problem were proposed by the linear combination of reconstruction errors caused by watermarking.Finally,the watermark was embed into 4× 4 subblocks with more non-zero coefficients by modulating the positive/negative correlation between residual coefficients and corresponding watermarking pattern,rather than previous algorithm directly adding watermark on the residual coefficients.Experimental results indicate that the proposed algorithm decreases the average structural similarity（SSIM） values within 0.005,increases the bitrates by about 1.00％; and the bit error ratio （BER） is below 0.15 in face of the attacks such as requantization transcoding,additive white Gaussian noise and brightness adjustment.The results satisfy the requirements of video watermarking in compressed domain for transparency,bitrate stability,robustness and real-time performance.