OmniHuman-1.5: Instilling an Active Mind in Avatars via Cognitive
  Simulation
Authors: name: Jianwen Jiang; name: Weihong Zeng; name: Zerong Zheng; name: Jiaqi Yang; name: Chao Liang; name: Wang Liao; name: Han Liang; name: Yuan Zhang; name: Mingyuan Gao
Published: 2025-08-26 17:15:26

Abstract: Existing video avatar models can produce fluid human animations, yet they
struggle to move beyond mere physical likeness to capture a character's
authentic essence. Their motions typically synchronize with low-level cues like
audio rhythm, lacking a deeper semantic understanding of emotion, intent, or
context. To bridge this gap, we propose a framework designed to
generate character animations that are not only physically plausible but also
semantically coherent and expressive. Our model, OmniHuman-1.5, is
built upon two key technical contributions. First, we leverage Multimodal Large
Language Models to synthesize a structured textual representation of conditions
that provides high-level semantic guidance. This guidance steers our motion
generator beyond simplistic rhythmic synchronization, enabling the production
of actions that are contextually and emotionally resonant. Second, to ensure
the effective fusion of these multimodal inputs and mitigate inter-modality
conflicts, we introduce a specialized Multimodal DiT architecture with a novel
Pseudo Last Frame design. The synergy of these components allows our model to
accurately interpret the joint semantics of audio, images, and text, thereby
generating motions that are deeply coherent with the character, scene, and
linguistic content. Extensive experiments demonstrate that our model achieves
leading performance across a comprehensive set of metrics, including lip-sync
accuracy, video quality, motion naturalness and semantic consistency with
textual prompts. Furthermore, our approach shows remarkable extensibility to
complex scenarios, such as those involving multi-person and non-human subjects.
Homepage: https://omnihuman-lab.github.io/v1_5/