History-Guided Video Diffusion
This work addresses a key bottleneck in video generation for AI and multimedia applications, offering incremental improvements in conditioning flexibility and guidance effectiveness.
The paper tackled the challenge of applying classifier-free guidance to video diffusion models with variable-length history frames, proposing the Diffusion Forcing Transformer (DFoT) and History Guidance methods, which significantly improved video generation quality and temporal consistency, enabling stable long video rollouts.
Classifier-free guidance (CFG) is a key technique for improving conditional generation in diffusion models, enabling more accurate control while enhancing sample quality. It is natural to extend this technique to video diffusion, which generates video conditioned on a variable number of context frames, collectively referred to as history. However, we find two key challenges to guiding with variable-length history: architectures that only support fixed-size conditioning, and the empirical observation that CFG-style history dropout performs poorly. To address this, we propose the Diffusion Forcing Transformer (DFoT), a video diffusion architecture and theoretically grounded training objective that jointly enable conditioning on a flexible number of history frames. We then introduce History Guidance, a family of guidance methods uniquely enabled by DFoT. We show that its simplest form, vanilla history guidance, already significantly improves video generation quality and temporal consistency. A more advanced method, history guidance across time and frequency further enhances motion dynamics, enables compositional generalization to out-of-distribution history, and can stably roll out extremely long videos. Project website: https://boyuan.space/history-guidance