Pixel estimation based video forgery detection

In this paper, we propose a novel technique to detect double quantization, which results due to double compression of a tampered video. The proposed algorithm uses principles of estimation theory to detect double quantization. Each pixel of a given frame is estimated from the spatially colocated pixels of all the other frames in a Group of Picture (GOP). The error between the true and estimated value is subjected to a threshold to identify the double compressed frame or frames in a GOP. The advantage of this algorithm is that it can detect tampering of I, P or B frames in a GOP with high accuracy. In addition, the technique can also detect forgery under wide range of double compression bitrates or quantization scale factors. We compare our experimental results against popular video forgery detection techniques and establish the effectiveness of the proposed technique.