Abstract: Considering the low robustness of existing watermarking algorithms based on High Efficiency Video Coding (HEVC) standard, a robust video watermarking algorithm for HEVC based on intra-frame prediction modes of multi-partitioning was proposed. Firstly, in order to eliminate the intra-frame error propagation after embedding the watermark, embeddable regions were selected and the texture direction was calculated for 4×4 luminance blocks. Secondly, a scheme was proposed that the 33 angular prediction modes were divided into four pattern sets, which were recorded as follows:upper horizontal, lower horizontal, upper vertical, lower vertical. Finally, the four pattern sets were mapped to the values of the current and next to be embedded watermarks. Once the current 4×4 luminance blocks met the pattern sets, the current 33 angular prediction modes were truncated into the current pattern sets and the watermark was embedded. The watermark was extracted by the texture direction and four prediction pattern sets at decoding side. The experimental results show that, the average Peak Signal to Noise Ratio (PSNR) of the proposed algorithm is almost unchanged. In addition, the proposed algorithm achieves the Bit Error Rate (BER) of 14.1% under re-encoded attacks. Therefore, the proposed algorithm has low video distortion and can well resist the re-encoded attacks in robustness.

Key words: High Efficiency Video Coding (HEVC), intra-frame prediction mode, video watermarking, texture direction

摘要： 针对现有基于高效视频编码（HEVC）标准的水印算法鲁棒性不足的问题，提出一种基于帧内预测模式多划分的HEVC鲁棒视频水印算法。首先，针对嵌入水印后帧内误差传播的问题，对4×4亮度块进行可嵌区域的选择，并计算4×4亮度块的纹理方向；其次，将33种角度预测模式划分为四种模式集，依次记为：上水平、下水平、上垂直、下垂直；最后，将当前以及下一待嵌入水印的值与模式集建立映射关系，通过判断当前4×4块属于哪个模式集来进行水印的嵌入，并将33种角度模式截断为其中一种模式集。解码端通过纹理方向和预测模式集提取水印。实验结果表明，所提算法的平均峰值信噪比维持不变，且在重编码攻击下的误码率（BER）为14.1%。由此可知，该算法对视频质量影响很小，在鲁棒性上可以抵抗重编码的攻击。

关键词: 高效视频编码, 帧内预测模式, 视频水印, 纹理方向