Abstract: Considering low robustness of existing video watermarking algorithms for High Efficiency Video Coding (HEVC), a robust video watermarking algorithm based on texture direction was proposed in this paper. Depending on the value of watermarking, the intra-frame angular prediction modes were divided into horizontal modes and vertical modes, and the texture direction for each prediction unit was calculated when the splitting mode was N×N during compressing coding. Once the texture direction was consistent with the direction represented by watermarking, the 33 angular prediction modes of current prediction unit would be truncated to the horizontal or vertical direction prediction modes, and a best prediction mode which could decide whether watermarking was embedded would be decided on the basis of rate distortion cost function. The location of embedded watermarking would be recorded as a key for extraction at decoding side. The experimental results show that the proposed algorithm has low bitrate increasing and low video distortion, and Error Bit Rate (BER) still remains at low value after the attack of noise, filtering and re-encoding, which means the proposed algorithm can be used to protect video copyright.

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

摘要： 针对现有基于高效视频编码的视频水印算法鲁棒性不足的问题,提出一种基于纹理方向的鲁棒视频水印算法。算法根据水印值将帧内角度预测模式分为水平方向和垂直方向两组,计算N×N分割编码时每个预测单元的纹理方向。当纹理方向与水印所表示的方向一致时,将当前预测单元的33种角度预测模式截断为水平方向或者垂直方向的预测模式,随后根据率失真代价函数决策出最优的预测模式,并判断水印是否嵌入。记录最终水印嵌入位置作为密钥,用于解码端提取。实验结果表明,该算法具有较小的码率增长和视频失真,在历经噪声、滤波和重编码等攻击后能保持较低的误码率(BER),说明该方案能用于视频版权保护。

关键词: 高效视频编码, 纹理方向, 视频水印, 鲁棒性, 帧内预测模式