Robust H.264/AVC video watermarking without intra distortion drift

摘要

A robust H.264/AVC video watermarking algorithm without intra distortion drift is proposed in this paper for the copyright protection of digital videos. The classic scheme prevented distortion from drifting by the classification of intra prediction modes, and different categories have different methods for modifying coefficient-pairs. Based on the reference pixels when 4x4 blocks of videos are encoded, the improved scheme proposed in this paper introduces a reclassification of intra prediction modes into avoiding distortion drift, which efficient enlarges the capacity of this kind of methods. Besides, the chosen principle of coefficient-pairs for watermarking is presented by theoretical and experimental analysis. By the means above, watermarked videos have controlled bit rate growth and guaranteed visual quality even if the capacity is enlarged. Then, pre-processing of watermarks reasonable reduce the bits needed to embed, which fixes the problem in classic scheme about limited capacity limits the size of watermarks. Meanwhile, spread-spectrum and Hamming code employed together not only promote robustness but also reduce computational complexity. Experimental results show that compared with the classic robust distortion drift-free methods, our algorithm maintains good visual performance with the enlarged capacity, and the strong robustness is kept without a huge increasement of bit rate.