Abstract: As a promising technology of copyright protection,video watermarking has attracted more and more attention in recent years.Different from the original domain scheme,the compressed domain scheme does not need to fully encode and decode video,so it has higher efficiency,and the video storage and transmission generally need to be compressed and encoded.Therefore,robust video watermarking scheme in compressed domain become a research hotspot.However,most of the existing schemes in the compressed domain use the individual QDCT coefficients in the compressed domain to embed the watermark,which makes the algorithm less robust.In order to improve the robustness of the compressed domain algorithm,a robust video watermarking scheme based on the QDCT global equalization strategy is proposed in this paper.Firstly,the blocks with both texture and high spatial complexity are selected as watermark blocks by using the number of non-zero coefficients,and then the sum of all coefficients in the two blocks is calculated respectively.According to the sum of the coefficients and the watermark information,all the non-zero coefficients in the sequence block are modified by the global equalization strategy to satisfy the block-pair coefficients rule,and the watermark is embedded.Experimental results show that the robust performance of the proposed scheme is better than that of the existing robust video watermarking scheme in resisting both recompression and noise attacks,increases by 8% and 9% respectively,while ensuring the high visual quality of the watermark-containing video.

Key words: Video watermarking, Robust watermarking, H.264 codec, Recompression attack, Equalizing strategy