Prediction mode based H.265/HEVC video watermarking resisting re-compression attack

This paper proposes a novel compressed domain robust watermarking scheme which embeds watermark by altering the intra prediction modes of 4 x 4 intra prediction blocks of the most recent high-definition video standards H.265/HEVC. Due to different compression architecture and higher number of intra prediction mode, the existing intra prediction mode based watermarking strategies for previous video standards such as H.264/AVC are not robust when those are directly applied for H.265/HEVC. This proposed work overcomes this shortcoming by reducing the synchronization error of watermark after re-compression attack in two stage. First, a spatial texture analysis is done based on number of non-zero transform coefficients of embedding blocks. Then, suitable candidate blocks for watermark embedding are selected based on 4 x 4 intra luma PB's sustainably and watermarked mode sustainability while maintaining visual quality and bit rate. In next stage, the robustness of the proposed method has been enhanced by grouping of intra prediction modes such a way that mode change due to re-compression can be closed within a group. Finally, each group is represented with two bits of watermark sequence and embedding have been done by altering prediction modes of selected 4 x 4 intra prediction block to the representative mode of the group denoted by the watermark bit pair. Experimental results on various test sequences show that the scheme is robust against re-compression with high QP values and robustness has been increased twice compared to existing intra prediction mode based watermarking schemes. Also, the proposed scheme has very low effect on the visual quality having least peak to signal ration of 28 dB for the watermarked test sequences and also has very similar bit increase rate compared to existing scheme.