Detection of Double-Compression in MPEG-2 Videos

In recent years, with the easy availability of digital video cameras and associated software to manipulate video, ascertaining the integrity and authenticity of digital videos has become an urgent and critical issue. In this paper, we propose a novel approach to detect double MPEG-2 compression which often occurs in digital video tampering. Specifically, we show how a doubly compressed MPEG-2 video sequence introduces convex pattern in the distribution of quantized DCT coefficients whose presence can be used as an evidence of tampering. Some commercial digital video cameras and multimedia editing softwares are introduced to simulate the process of double MPEG-2 compression, and a series of experiments show that the proposed scheme can effectively detect double MPEG-2 compression at different output bit-rates. Excellent test results verify that our proposed algorithm is of great practical value.