Cyber-Security & Applied Resilience Center

MSc Cyber Security · Student Research

Catching deepfakes in motion, not in a single frame

A hybrid CNN–Transformer that reads short video clips instead of one image at a time — learning the temporal tells of synthetic faces that frame-level detectors miss.

Course
CS511
Architecture
EfficientNet-B0 + Transformer
Dataset
FaceForensics++ (C23)
Task
Binary · REAL / FAKE
Abstract

Why one frame isn’t enough

Deepfake generation has advanced to the point where a single synthesized frame can look flawless, making frame-by-frame detection increasingly unreliable. This project pairs the spatial feature extraction of EfficientNet-B0 with the temporal modelling of a multi-head self-attention Transformer. Instead of classifying individual frames, the model processes short clips of 8 consecutive frames. A learnable classification (CLS) token is prepended to the sequence and, after a 4-layer / 8-head Transformer encoder, produces a global temporal summary used for the final REAL / FAKE decision. Evaluated on FaceForensics++ C23 against a single-frame CNN baseline with the same backbone, the temporal model lifts ranking quality (AUC-ROC) substantially — and its attention weights reveal which frames drove each decision, giving the interpretable evidence digital-forensics work demands.

Results · Validation set

8-frame temporal model vs. single-frame baseline

Same EfficientNet-B0 backbone, same data, same training budget — the only change is whether the model sees one frame or eight. Best validation scores shown.

Accuracy
65.0%
= baseline · 0.650
Matched — accuracy alone hides the ranking gain.
AUC–ROC
0.833
▲ +0.173 vs 0.660
Far stronger separation of real from fake.
F1 Score
0.627
▼ −0.039 vs 0.667
Small trade-off at the default 0.5 threshold.
Single-frame CNN (baseline) 8-frame CNN–Transformer (ours)
Accuracytie
Baseline0.650
Ours0.650
AUC–ROC+0.173 ours
Baseline0.660
Ours0.833
F1 Score−0.039 ours
Baseline0.667
Ours0.627
0.00.51.0
Per-epoch validation AUC and accuracy: single-frame baseline vs 8-frame model
Per-epoch validation curves across the 10-epoch run for both models — AUC-ROC (left) and accuracy (right).
Method

From pixels to a temporal verdict

Four stages turn a raw clip into an interpretable REAL / FAKE decision.

01 — Sample
8-frame clip
Consecutive frames sampled at a fixed step, cropped to 224×224.
02 — Encode
EfficientNet-B0
Each frame becomes a 1280-d spatial feature, projected to 256-d.
03 — Relate
Transformer ×4
8 attention heads model how frames relate over time; a CLS token gathers a global summary.
04 — Decide
REAL / FAKE
The CLS token drives classification — with per-frame attention as evidence.

SPACE What each frame contains

EfficientNet-B0 is a compact, accurate CNN that extracts appearance features — edges, textures, and facial detail — from every individual frame.

TIME How frames relate

The Transformer’s self-attention compares all 8 frames at once, surfacing the temporal inconsistencies — blinking, flicker, texture drift — that only appear in motion.

Project team

Built by CS511 · Cyber Security

Master of Science in Cyber Security — College of Engineering & IT, University of Dubai.

MA
Mohamed Ahmed Eisa Aljallaf Al Ali
Project member
AA
Abdullah Ghanem Khamis Alyadea Almarzooqi
Project member
AK
Abdulrahman Khalid Ibrahim Abdulrahim Alkassim
Project member
NS
Naser Suhail Mohamed Suhail Alsereidi
Project member

Supervised by Dr. Hussam Al Hamadi — Program Director, MSc Cyber Security · Head, Cyber-Security & Applied Resilience Center (C-SAR).

Materials

Report & code

Full technical report and the training / evaluation notebook.

The model is trained on the FaceForensics++ dataset, released under its own academic-use license. Dataset videos and trained weights are not redistributed here; the notebook reproduces results once FaceForensics++ access is obtained.

Cyber-Security & Applied Resilience Center (C-SAR) · University of DubaiDeepfake Video Detection · Hybrid CNN–Transformer

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