结力引导：驯服自回归视频扩散模型实现实时无限交互式人像动画

Knot Forcing: Taming Autoregressive Video Diffusion Models for Real-time Infinite Interactive Portrait Animation

December 25, 2025

作者: Steven Xiao, Xindi Zhang, Dechao Meng, Qi Wang, Peng Zhang, Bang Zhang

cs.AI

摘要

实时人像动画对于虚拟助手和实时虚拟化身等交互应用至关重要，需要具备高视觉保真度、时间连贯性、超低延迟以及对参考图像和驱动信号等动态输入的即时响应能力。尽管基于扩散的模型能实现优异画质，但其非因果特性阻碍了流式部署。因果自回归视频生成方法虽支持逐帧高效生成，但存在误差累积、片段边界运动不连续以及长期一致性退化等问题。本研究提出名为"结式强制"的创新流式框架，通过三项核心设计解决上述挑战：(1)采用分块生成策略，通过缓存参考图像的KV状态实现全局身份保持，并利用滑动窗口注意力进行局部时序建模；(2)设计时序结模块，通过重叠相邻数据块并借助图像-视频条件传递时空线索，实现片段间运动平滑过渡；(3)引入"前瞻运行"机制，在推理过程中动态更新参考帧的时序坐标，使其语义语境始终领先于当前生成帧，从而保障长期连贯性。该框架可在消费级GPU上实现无限序列的高保真度、时序稳定且具备交互性的实时人像动画，展现出卓越的视觉稳定性。

English

Real-time portrait animation is essential for interactive applications such as virtual assistants and live avatars, requiring high visual fidelity, temporal coherence, ultra-low latency, and responsive control from dynamic inputs like reference images and driving signals. While diffusion-based models achieve strong quality, their non-causal nature hinders streaming deployment. Causal autoregressive video generation approaches enable efficient frame-by-frame generation but suffer from error accumulation, motion discontinuities at chunk boundaries, and degraded long-term consistency. In this work, we present a novel streaming framework named Knot Forcing for real-time portrait animation that addresses these challenges through three key designs: (1) a chunk-wise generation strategy with global identity preservation via cached KV states of the reference image and local temporal modeling using sliding window attention; (2) a temporal knot module that overlaps adjacent chunks and propagates spatio-temporal cues via image-to-video conditioning to smooth inter-chunk motion transitions; and (3) A "running ahead" mechanism that dynamically updates the reference frame's temporal coordinate during inference, keeping its semantic context ahead of the current rollout frame to support long-term coherence. Knot Forcing enables high-fidelity, temporally consistent, and interactive portrait animation over infinite sequences, achieving real-time performance with strong visual stability on consumer-grade GPUs.