TY - JOUR T1 - Video Integrity Verification and GOP Size Estimation via Generalized Variation of Prediction Footprint JF - IEEE Transactions on Information Forensics and Security Y1 - 2020 A1 - David Vázquez-Padín A1 - Marco Fontani A1 - Dasara Shullani A1 - Fernando Pérez-González A1 - Alessandro Piva A1 - Mauro Barni KW - B-frames KW - double compression detection KW - GOP size estimation KW - rate distortion optimization KW - video forensics AB -

The Variation of Prediction Footprint (VPF), formerly used in video forensics for double compression detection and GOP size estimation, is comprehensively investigated to improve its acquisition capabilities and extend its use to video sequences that contain bi-directional frames (B-frames). By relying on a universal rate-distortion analysis applied to a generic double compression scheme, we first explain the rationale behind the presence of the VPF in double compressed videos and then justify the need of exploiting a new source of information such as the motion vectors, to enhance the VPF acquisition process. Finally, we describe the shifted VPF induced by the presence of B-frames and detail how to compensate the shift to avoid misguided GOP size estimations. The experimental results show that the proposed Generalized VPF (G-VPF) technique outperforms the state of the art, not only in terms of double compression detection and GOP size estimation, but also in reducing computational time.

VL - 15 IS - 1 ER - TY - CONF T1 - Localization of Forgeries in MPEG-2 Video through GOP Size and DQ analysis T2 - IEEE International Workshop on Multimedia Signal Processing (MMSP) Y1 - 2013 A1 - Daniele Labartino A1 - Tiziano Bianchi A1 - Alessia De Rosa A1 - Marco Fontani A1 - David Vázquez-Padín A1 - Alessandro Piva A1 - Mauro Barni AB -

This work addresses forgery localization in MPEG-2 compressed videos. The proposed method is based on the analysis of Double Quantization (DQ) traces in frames that were encoded twice as intra (i.e., I-frames).  Employing a state-of-the-art method, such frames are located in the video under analysis by estimating the size of the Group Of Pictures (GOP) that was used in the first compression; then, the DQ analysis is devised for the MPEG-2 encoding scheme and applied to frames that were intra-coded in both the first and second compression. In such a way, regions that were manipulated between the two encodings are detected. Compared to existing methods based on double quantization analysis, the proposed scheme makes forgery localization possible on a wider range of settings.

 
JF - IEEE International Workshop on Multimedia Signal Processing (MMSP) CY - Pula (Sardinia), Italy U1 -

Top 10% Award

ER - TY - Generic T1 - Near optimal detection of quantized signals and application to JPEG forensics T2 - 2013 IEEE International Workshop on Information Forensics and Security (WIFS) Y1 - 2013 A1 - Tiziano Bianchi A1 - Alessandro Piva A1 - Fernando Pérez-González JF - 2013 IEEE International Workshop on Information Forensics and Security (WIFS) CY - Guangzhou, China UR - http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6707813 ER - TY - CONF T1 - Detection of video double encoding with GOP size estimation T2 - IEEE International Workshop on Information Forensics and Security (WIFS) Y1 - 2012 A1 - David Vázquez-Padín A1 - Marco Fontani A1 - Tiziano Bianchi A1 - Pedro Comesaña A1 - Alessandro Piva A1 - Mauro Barni AB -

Video forensics is an emerging discipline, that aims at inferring information about the processing history undergone by a digital video in a blind fashion. In this work we introduce a new forensic footprint and, based on it, propose a method for detecting whether a video has been encoded twice; if this is the case, we also estimate the size of the Group Of Pictures (GOP) employed during the first encoding. As shown in the experiments, the footprint proves to be very robust even in realistic settings (i.e., when encoding is carried out using typical compression rates), that are rarely addressed by existing techniques.

JF - IEEE International Workshop on Information Forensics and Security (WIFS) PB - IEEE CY - Tenerife, Spain ER -