LSF-Animation: Label-Free Speech-Driven Facial Animation via Implicit Feature Representation
Xin Lu, Chuanqing Zhuang, Chenxi Jin, Zhengda Lu, Yiqun Wang, Wu Liu, Jun Xiao
TL;DR
This work introduces LSF-Animation, a label-free pipeline for speech-driven 3D facial animation that leverages implicit emotion embeddings from audio and identity cues from a neutral face mesh. Central to the approach is the Hierarchical Interaction Fusion Block (HIFB), which enables dense, progressive cross-modal fusion between emotion, motion, and identity streams, preserving temporal dynamics and enhancing upper-face expressiveness. The model trains in two stages with a VQ-VAE motion codebook and a SIE-Encoder that maps audio and neutral geometry to latent motion, achieving strong identity generalization and peak expressiveness on the 3DMEAD dataset, beating state-of-the-art methods while avoiding manual emotion or identity labeling. These results highlight the practical potential of label-free, emotion-aware facial animation for scalable digital humans in real-world applications.
Abstract
Speech-driven 3D facial animation has attracted increasing interest since its potential to generate expressive and temporally synchronized digital humans. While recent works have begun to explore emotion-aware animation, they still depend on explicit one-hot encodings to represent identity and emotion with given emotion and identity labels, which limits their ability to generalize to unseen speakers. Moreover, the emotional cues inherently present in speech are often neglected, limiting the naturalness and adaptability of generated animations. In this work, we propose LSF-Animation, a novel framework that eliminates the reliance on explicit emotion and identity feature representations. Specifically, LSF-Animation implicitly extracts emotion information from speech and captures the identity features from a neutral facial mesh, enabling improved generalization to unseen speakers and emotional states without requiring manual labels. Furthermore, we introduce a Hierarchical Interaction Fusion Block (HIFB), which employs a fusion token to integrate dual transformer features and more effectively integrate emotional, motion-related and identity-related cues. Extensive experiments conducted on the 3DMEAD dataset demonstrate that our method surpasses recent state-of-the-art approaches in terms of emotional expressiveness, identity generalization, and animation realism. The source code will be released at: https://github.com/Dogter521/LSF-Animation.
