  We consider the task of animating 3D facial geometry from speech signal.
Existing works are primarily deterministic, focusing on learning a one-to-one
mapping from speech signal to 3D face meshes on small datasets with limited
speakers. While these models can achieve high-quality lip articulation for
speakers in the training set, they are unable to capture the full and diverse
distribution of 3D facial motions that accompany speech in the real world.
Importantly, the relationship between speech and facial motion is one-to-many,
containing both inter-speaker and intra-speaker variations and necessitating a
probabilistic approach. In this paper, we identify and address key challenges
that have so far limited the development of probabilistic models: lack of
datasets and metrics that are suitable for training and evaluating them, as
well as the difficulty of designing a model that generates diverse results
while remaining faithful to a strong conditioning signal as speech. We first
propose large-scale benchmark datasets and metrics suitable for probabilistic
modeling. Then, we demonstrate a probabilistic model that achieves both
diversity and fidelity to speech, outperforming other methods across the
proposed benchmarks. Finally, we showcase useful applications of probabilistic
models trained on these large-scale datasets: we can generate diverse
speech-driven 3D facial motion that matches unseen speaker styles extracted
from reference clips; and our synthetic meshes can be used to improve the
performance of downstream audio-visual models.
