Abstract:

H.264/AVC video watermarking plays an important role in video copyright protection and information hiding.At present,the existing watermarking researches lack the consideration of the variable complexity of the video frame in the process of watermark embedding,which can easily lead to two problems:first,these watermark algorithms may not be able to fully embed the required watermark in frames with low picture complexity,and second,the redundancy of frames with high picture complexity cannot be fully utilized.Therefore,in this paper we analyze the factors of frame complexity in the process of video coding,and propose an adaptive watermarking algorithm based on the complexity of the video frame.In the proposed algorithm,the complexity degree of the current key frame is predicted using the total number of Intra_4×4 sub macroblocks of the previous key frame that satisfy the embedding conditions.The repetition time of embedding for each watermark bit is adjusted automatically according to the predicted complexity degree to achieve adaptiveness.A key frame with a prediction error is labelled an invalid frame.The watermark extraction is conducted by majority voting.Experimental results show that the proposed algorithm achieves watermark invisibility,and code stream stability as well,which outperforms the other recent algorithms.The algorithm is instructive to the research based on repeatedly embedding watermark bits.

Key words: H.264, digital watermark, adaptive, majority voting