A Cavlc-based Video Watermarking Scheme for H.264/avc Codec

Forensics for digital data has become more and more important, especially for video surveillance systems. Recently, H.264/AVC CODEC has been widely applied to video surveillance systems. In this paper, therefore, a novel video watermarking scheme for H.264/AVC CODEC is proposed. It embeds a watermark bit by adaptively truncating the last nonzero quantized AC coefficients in a 4 × 4 luminance block. The existence of truncated coefficient has least perceptual degradation and least influence on successive prediction coding. Thus, the scheme could constrain the perceptual degradation, which is caused by embedding watermark, within an ideal degree. Experimental results show that the proposed scheme does not increase but even reduces the bit rate after embedding watermarks in general cases. Besides, the accuracy of extracted watermark bits after the re-encoding attack could be maintained over 80%. Moreover, since the scheme is lowcomplexity and implemented in the encoder, it can be easily adopted by real-time video applications.