1.
Misinformation on the internet:
Video and AI
Vasileios Mezaris
CERTH-ITI
Presentation at the "Age of misinformation: an interdisciplinary outlook on fake news" webinar
17th December 2020

2.
Vasileios Mezaris, December 2020
Why focus on video?
• Powerful, sensational, persuasive medium
• “Believe nothing you hear, and only one half that you see.”
(Edgar Allan Poe, Nov. 1845)

3.
Vasileios Mezaris, December 2020
Can I believe what I see?
• Is this video exactly as captured by the camera? (detection)
• What has been altered, and how do you know? (explanation)
• Why has it been altered? (understanding intent)
→ Intent is important; are the below edited videos carriers of
misinformation? Should they be banned from internet platforms?
Video credits: Media Forensics Challenge (MFC) dataset; GRIP, University Federico II, Naples

4.
Vasileios Mezaris, December 2020
What is the role of AI?
• A powerful enabler of detecting and understanding video
manipulations
• But also a tool for promoting misinformation! (deepfakes; can
facilitate Distributed Denial of Truth (DDoT) attacks)
Prediction: Tampered Tampering localization / explanation (kind of…)

5.
Vasileios Mezaris
Vasileios Mezaris, December 2020
InVID-WeVerify Verification Plugin: a “Swiss army knife” for
video verification
A browser plugin to debunk fake news
and to verify videos and images
>30.000
users
• Check prior video use: reverse video
search on the Web
• Check contextual information: Social-
media-based contextual analysis
• Keyframe/image inspection by
magnifying glass
• Check image (keyframe) forensics
Free! Get it from:
https://www.invid-project.eu/verify
Verifying videos: a browser plugin
H2020 IA, 2016-2018
Coordinator: CERTH

6.
Vasileios Mezaris
Vasileios Mezaris, December 2020
A CERTH-ITI / InVID webpage for video fragmentation and reverse
web search; helps to quicky catch the “easy fakes” (try it!):
http://multimedia3.iti.gr/video_
fragmentation/service/start.html
Verifying videos: a web service
H2020 IA, 2016-2018
Coordinator: CERTH

7.
Vasileios Mezaris
Vasileios Mezaris, December 2020
https://www.youtube.com/watch?v=OVAxQA3gMEo
“Video, the crowd in panic flees
from Notre Dame in Paris after
the attack of an armed man”
A video verification example

8.
Vasileios Mezaris
Vasileios Mezaris, December 2020
AI4Media: A European Excellence Centre for Media, Society and
Democracy
• AI against disinformation is one of our use cases
• We are advancing the SoA in AI, in various directions (e.g. explainability, robustness)
More AI for verifying videos
H2020 RIA, 2020-2024
Coordinator: CERTH

9.
Vasileios Mezaris
Vasileios Mezaris, December 2020
• Whether a video is a carrier of misinformation is not an easy yes/no question; may require
detecting & interpreting manipulations, and understanding intent
• Even relatively simple approaches, such as video fragmentation for reserse Web search, can
have great impact [1]
• AI is the enabler of more elaborate manipulation detection [2], but can also be a risk
[1] D. Teyssou, J.-M. Leung, E. Apostolidis, K. Apostolidis, S. Papadopoulos, M. Zampoglou, O. Papadopoulou, V. Mezaris, "The InVID Plug-in:
Web Video Verification on the Browser", Proc. Int. Workshop on Multimedia Verification (MuVer 2017) at ACM Multimedia 2017, Mountain
View, CA, USA, October 2017.
[2] G. Mercier, F. Markatopoulou, R. Cozien, M. Zampoglou, E. Apostolidis, A. Metsai, S. Papadopoulos, V. Mezaris, I. Patras, I. Kompatsiaris,
"Detecting Manipulations in Video", in book "Video Verification in the Fake News Era", V. Mezaris, L. Nixon, S. Papadopoulos, D. Teyssou
(Eds.), pp. 161-189, Springer, 2019.
[3] "Video verification in the fake news era", V. Mezaris, L. Nixon, S. Papadopoulos, D. Teyssou (Editors), Springer, 2019.
Concluding remarks
• Complete automation is not easy; often, AI+human symbiosis is the key [3]
• New challenges & advances in AI (e.g. Explainable AI) will create new
opportunities for even greater use of AI in verification (of video and more)

10.
Vasileios Mezaris, December 2020
Questions?
Contact: Dr. Vasileios Mezaris
Research Director, Head of Intelligent Digital Transformation Laboratory
Information Technologies Institute (ITI) /
Centre for Research and Technology Hellas (CERTH)
Thermi-Thessaloniki, Greece
Email: bmezaris@iti.gr, web: http://www.iti.gr/~bmezaris/
This work was supported in part by the EU’s Horizon 2020 programme
grant agreements H2020-687786 InVID and H2020-951911 AI4Media