Semi-Fragile Watermarking Scheme for Authentication of MPEG-1/2 Coded Videos

This paper presents semi-fragile watermarking system for video authentication. We focus on protection and verification of the I-frame´s integrity in MPEG-1/2 coded videos. Using the DC difference between blocks, we compute binary feature string with semi-fragile characteristics from the I-frames. We use this feature string as a key to generate binary watermark, and then robustly embed this content-dependent watermark into the I-frame. Using this method, it is possible to differentiate among content-preserving and content-changing modifications of the video. The watermark is embedded into DCT-domain using binary quantization index modulation. Watermark detection is performed without use of the original video. The experimental results show the robustness of this system to content-preserving manipulations and its fragility to content-changing manipulations.