DIN-CTS: Low-Complexity Depthwise-Inception Neural Network with Contrastive Training Strategy for Deepfake Speech Detection
Lam Pham, Dat Tran, Phat Lam, Florian Skopik, Alexander Schindler, Silvia Poletti, David Fischinger, Martin Boyer
TL;DR
This work tackles deepfake speech detection with a low-complexity DIN that uses depthwise and inception-inspired blocks to efficiently learn discriminative features. A three-stage Contrastive Training Strategy (CTS) combines multi-class, contrastive, and bonafide-variance objectives, culminating in a Gaussian model over bonafide embeddings for inference. On ASVspoof 2019 LA, the single-model DIN with CTS (M3) achieves an EER of $4.6\%$, accuracy of $95.4\%$, F1 of $97.3\%$, and AUC of $98.9\%$ with only $1.77$ million parameters and $985$ MFLOPS, outperforming top single-system submissions. The approach uses a Mahalanobis distance to compare test embeddings with the bonafide distribution, enabling potential real-time deployment for DSD tasks. Key contributions include the low-complexity DIN architecture, the three-stage CTS, and the probabilistic inference framework for robust detection with unseen generators, supported by detailed ablations and visualizations.
Abstract
In this paper, we propose a deep neural network approach for deepfake speech detection (DSD) based on a lowcomplexity Depthwise-Inception Network (DIN) trained with a contrastive training strategy (CTS). In this framework, input audio recordings are first transformed into spectrograms using Short-Time Fourier Transform (STFT) and Linear Filter (LF), which are then used to train the DIN. Once trained, the DIN processes bonafide utterances to extract audio embeddings, which are used to construct a Gaussian distribution representing genuine speech. Deepfake detection is then performed by computing the distance between a test utterance and this distribution to determine whether the utterance is fake or bonafide. To evaluate our proposed systems, we conducted extensive experiments on the benchmark dataset of ASVspoof 2019 LA. The experimental results demonstrate the effectiveness of combining the Depthwise-Inception Network with the contrastive learning strategy in distinguishing between fake and bonafide utterances. We achieved Equal Error Rate (EER), Accuracy (Acc.), F1, AUC scores of 4.6%, 95.4%, 97.3%, and 98.9% respectively using a single, low-complexity DIN with just 1.77 M parameters and 985 M FLOPS on short audio segments (4 seconds). Furthermore, our proposed system outperforms the single-system submissions in the ASVspoof 2019 LA challenge, showcasing its potential for real-time applications.
