Multimodal Deepfake Detection System: An Intelligent Anti-Forgery Solution Integrating Audio-Visual Cues

The multimodal deepfake detection system introduced in this article supports four detection modes: audio, image, video, and audio-video joint detection. Through dynamic model selection and cross-modal consistency analysis, it effectively identifies various AI-generated fake content, providing a modular and scalable technical solution for authenticity verification of digital content to address the information security challenges posed by deepfakes.

The development of generative AI has led to the proliferation of deepfake technology. Face-swapped videos, voice cloning, etc., have brought issues related to information authenticity, privacy, and social trust. Traditional single-modal detection methods are difficult to deal with complex forgery techniques, so there is an urgent need for new detection solutions that integrate multi-source information.

The system uses a dynamic model selection mechanism to adapt to different input types:

1. Audio-specific model: Analyzes forgery traces such as abnormal spectral continuity and phase inconsistency. It extracts Mel spectrograms based on Librosa and performs classification via deep learning;
2. Image-specific model: Detects artifacts at facial boundaries, inconsistent eye reflections, etc. It combines OpenCV preprocessing with CNN for feature extraction;
3. Video-specific model: Captures inter-frame issues like temporal flickering and incoherent movements. It uses 3D convolution or LSTM to model temporal dependencies;
4. Multimodal joint model: Detects cross-modal blind spots such as lip-sync mismatches and inconsistent audio-video emotions. It learns correlation patterns through a Transformer fusion network.

The system adopts a modular architecture, with code structure including directories like models (modal-specific models), data, and utils. Its advantages are flexible deployment, independent optimization, and easy scalability. The tech stack is based on the Python ecosystem: deep learning frameworks (PyTorch/TensorFlow), computer vision (OpenCV), audio processing (Librosa), numerical computing (NumPy). The models use CNN architectures such as ResNet/EfficientNet and multimodal fusion inspired by CLIP.

Experimental results show:

• Single-modal models have good accuracy in their respective domains;
• Multimodal models improve robustness through cross-modal analysis, especially showing significant effects on combined forgeries (e.g., face-swapped videos with original audio that have lip-sync mismatches);
• Confidence scores provide decision-making references, and thresholds can be adjusted to adapt to different scenarios.

Application scenarios include marking suspicious content on social media, verifying materials by news agencies, preventing voice fraud in finance, and identifying evidence in judicial forensics. Future directions: Transformer-based multimodal fusion, automatic modal detection, real-time inference optimization, and Web-side deployment.

Deepfake creation and detection are an ongoing arms race. This system demonstrates the value of integrating multi-source information to address complex threats. It needs to evolve continuously to keep up with the development of forgery technologies, establish detection advantages through cross-modal innovation, and become an important infrastructure for maintaining digital trust.