Design choices and fusion strategies
Fine-tuned (EfficientNet-B0 + audio CNN) and frozen (CLIP, XLS-R, AASIST + small head) models, each as a single modality, with feature-level fusion, and with late fusion, without and with augmentation. "+ SyncNet" adds six lip-sync numbers to the step above it. "Extra training step" is the same logistic regression without SyncNet, so the SyncNet comparison is fair.
Precision depends on how many real and fake videos a test set has. Most test videos are fake, so fake precision is high for every model (a detector that calls every video fake would already score 0.977, 0.947 and 0.876), and real precision is low. Recall and macro F1 are the fairer comparison across datasets.