@article {975,
	title = {Video Integrity Verification and GOP Size Estimation via Generalized Variation of Prediction Footprint},
	journal = {IEEE Transactions on Information Forensics and Security},
	volume = {15},
	year = {2020},
	month = {12/2019},
	pages = {1815-1830},
	chapter = {1815},
	abstract = {<p>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.</p>},
	keywords = {B-frames, double compression detection, GOP size estimation, rate distortion optimization, video forensics},
	author = {David V{\'a}zquez-Pad{\'\i}n and Marco Fontani and Dasara Shullani and Fernando P{\'e}rez-Gonz{\'a}lez and Alessandro Piva and Mauro Barni}
}
@conference {967,
	title = {Prediction Residue Analysis in MPEG-2 Double Compressed Video Sequences},
	booktitle = {EUSIPCO},
	year = {2019},
	month = {09/2019},
	pages = {1109-1113},
	address = {A Coru{\~n}a, Spain},
	abstract = {<p>In video forensics, the study of the prediction residue across successive frames is key to verify the integrity of digital videos. Focusing on an MPEG-2 double compression scheme, we analyze how the variance of the prediction residue evolves during the second compression depending on the type of frame (either I or P) employed in the first encoding and exploring different compression strengths and deadzone widths for quantization. This analysis reveals that the width of the quantizer deadzones actually affects the performance of existing methods based on the Variation of Prediction Footprint (VPF) for double compression detection and Group Of Pictures (GOP) size estimation. The predicted behavior from the theoretical characterization of the prediction residue is confirmed through experimental results with real video sequences.</p>},
	keywords = {double compression detection, GOP size estimation, MPEG-2, prediction residue analysis, video forensics},
	author = {David V{\'a}zquez-Pad{\'\i}n and Fernando P{\'e}rez-Gonz{\'a}lez}
}
