H.264帧间模式选择水印算法研究

针对H.264/AVC视频编码标准，提出一种基于帧间模式选择的视频水印算法。在亚宏块模式选择的基础上，算法先对二值图像进行Arnold置乱以及turbo码编码形成待嵌入的水印序列；然后，根据水印数据修改亚宏块模式以改变子块数目的奇偶性，并将修改前后SAD值变化最小的亚宏块作为嵌入域；最后，通过隔帧嵌入、增大滤波器滤波强度来降低水印的嵌入对视频质量的影响。仿真结果表明，在不影响水印正确提取的前提下，算法对视频码率影响较小，具有很好的抗噪声能力，并且在视频PSNR方面能取得较好的效果。 

Research of Watermarking Algorithm Based on H.264 Inter-frame Mode Selecting

Abstract: According to the H.264/AVC video encoding standard,a robust video watermarking algorithm based on inter-frame mode selection has been proposed.On the foundation of selecting the mode of sub-macroblock,algorithm selected a binary digital picture as watermark image at first;After scrambling and coding the watermark image it scaned the image into one-dimensional vector and then used the binary sequence as watermark information to be embedded. Secondly, according to the value of watermark sequence,the parity of the sub-block’s number was modified along with the mode of sub-macroblock,and those sub-macroblocks whose SAD value have minimum change after modification was selected as the embedded region;Finally,the quality of video was improved by embedding the watermark into discontinuous frame and increasing the strength of the filter.Under the premise that does not affect the correct extraction of watermark,simulation results have shown that the proposed algorithm has good robustness against noise attacking and the watermarking is invisible and robust.Meanwhile,it has little influence on the bit rate,and also has good effect in the PSNR of video.