Forensic characterization of pirated movies: digital cinema cam vs. optical disc rip

A large portion of pirate movies illegally shared over the Internet is either a camcorded copy of a projection in a digital cinema or is directly ripped from optical discs such as DVDs and Blu-ray discs. In this paper, we introduce a classifier that automatically discriminates between these two types of piracy in an effort to provide tools that help streamlining the whole forensic analysis process. This oracle relies on tell-tale visual artifacts that reveal the occurrence of camcording. We survey three alternate discriminative features relating to temporal flicker, color gamut, and edge orientation and detail how to combine them to obtain accurate classification. Experiments conducted on a large corpus of real pirated movies clearly demonstrate the feasibility of such classification.