用于AVS码流复制控制的数字水印

为应对日益严重的盗版问题，针对AVS视频标准提出了一种基于哥伦布码字调制的码流域水印嵌入算法，实现对视频码流信息的完整性保护并用于复制控制．在AVS码流中，基于码字与待嵌入比特之间的映射规则，采用等码长对码调制算法，调制相应的哥伦布码字实现水印信息的嵌入．信息的嵌入过程中，为了不影响视频重建图像的主客观质量，限制了水印信息的嵌入点，增强了水印信息的隐蔽性．信息的提取过程不需要原始视频内容，也不需完全解码，而只要对码流中的哥伦布码字进行解码即可．实验结果表明，所提出的水印算法在获得较高嵌入率的同时，不改变码流的比特率，基本不影响视频的主客观质量，没有增加大量的运算，复杂度低，速度快，能有效将水印信息嵌入到视频码流中，实现视频数据的复制控制功能．

Digital Video Watermarking in AVS Compressed Stream for Copy Control

To achieve content authentication and copyright protection by noticing the serious problem of copyright piracy, a novel watermarking algorithm based on Exp-Golomb code modulation of audio video coding standard （AVS） was proposed. In the bit stream of AVS video compression standard, watermarking was implemented by modu- lating the corresponding Exp-Golomb code, which is based on the mapping rules between these codes and the information bits. The embedding positions were limited to enhance the quality of the reconstructed images. The extraction of information needs no original media, and merely requires decoding the Exp-Golomb code from bit stream rather than decoding the whole video, The experimental results show that the presented watermarking method achieves comparatively high embedding rate without increasing the bitrate of data, and has almost no impact on video quality subjectively as well as objectively. The method introduces no complicated computation, and therefore the implementation is fast. Such properties make the presented method effective, and hence make it a way to copy control of the video data,