基于直方图平移的视频密文域大容量可逆信息隐藏

针对视频密文域可逆信息隐藏（RDH）嵌入容量不高的问题，提出一种基于直方图平移的视频密文域大容量可逆信息隐藏方案。首先，利用流密码算法对4×4亮度帧内预测模式和运动矢量差值（MVD）的符号位进行加密，形成视频密文域；其次，构造MVD的二维直方图，设计关于（0,0）对称的直方图平移算法；最后，在MVD密文域中进行直方图平移，实现可分离的视频密文域可逆信息隐藏。实验结果表明，与对比方案相比，所提方案的嵌入容量平均提升263.3%，加密视频的平均峰值信噪比（PSNR）最高不超过15.956 dB，含密的解密视频的平均PSNR均能达到30 dB以上。所提方案可以有效提升嵌入容量，适用于更多类型的视频序列。

High-capacity reversible data hiding in encrypted videos based on histogram shifting

Aiming at the low embedding capacity of Reversible Data Hiding （RDH） in encrypted videos， a high-capacity RDH scheme in encrypted videos based on histogram shifting was proposed. Firstly， 4×4 luminance intra-prediction mode and the sign bits of Motion Vector Difference （MVD） were encrypted by stream cipher， and then a two-dimensional histogram of MVD was constructed， and （0，0） symmetric histogram shifting algorithm was designed. Finally， （0，0） symmetric histogram shifting algorithm was carried out in the encrypted MVD domain to realize separable RDH in encrypted videos. Experimental results show that the embedding capacity of the proposed scheme is increased by 263.3% on average compared with the comparison schemes， the average Peak Signal-to-Noise Ratio （PSNR） of encrypted video is less than 15.956 dB， and the average PSNR of decrypted video with secret can reach more than 30 dB. The proposed scheme effectively improves the embedding capacity and is suitable for more types of video sequences.