ProbTalk3D-X: Prosody enhanced non-deterministic emotion controllable speech-driven 3D facial animation synthesis

Audio-driven 3D facial animation synthesis has been an active field of research with attention from both academia and industry. While there are promising results in this area, recent approaches largely focus on lip-sync and identity control, neglecting the role of emotions and emotion control in the generative process. That is mainly due to the lack of emotionally rich facial animation data and algorithms that can synthesize speech animations with emotional expressions at the same time. In addition, the majority of the models are deterministic, meaning given the same audio input, they produce the same output motion. We argue that emotions and non-determinism are crucial to generate diverse and emotionally-rich facial animations. In this paper, we present ProbTalk3D-X by extending a prior work ProbTalk3D- a two staged VQ-VAE based non-deterministic model, by additionally incorporating prosody features for improved facial accuracy using an emotionally rich facial animation dataset, 3DMEAD. Further, we present a comprehensive comparison of non-deterministic emotion controllable models (including new extended experimental models) leveraging VQ-VAE, VAE and diffusion techniques. We provide an extensive comparative analysis of the experimental models against the recent 3D facial animation synthesis approaches, by evaluating the results objectively, qualitatively, and with a perceptual user study. We highlight several objective metrics that are more suitable for evaluating stochastic outputs and use both in-the-wild and ground truth data for subjective evaluation. Our evaluation demonstrates that ProbTalk3D-X and original ProbTalk3D achieve superior performance compared to state-of-the-art emotion-controlled, deterministic and non-deterministic models. We recommend watching the supplementary video for visual quality judgment. The entire codebase including the extended models is publicly available. 1