Paper Overview
- Field: Computer Vision (CV)
- Authors: Yanzuo Lu, Ronglai Zuo, Jiankang Deng
- Release date: 2026-05-16
- arXiv: 2505.08629
Abstract
Causal autoregressive video diffusion models support real-time streaming generation by extrapolating future chunks from previously generated content. Distilling such generators from high-fidelity bidirectional teachers yields competitive few-step models, yet a persistent gap between the history distributions encountered during training and those arising at inference constrains generation quality over long horizons. We introduce the Real-time Autoregressive Video Extrapolation Network (RAVEN), a training-time test framework that repacks each self rollout into an interleaved sequence of clean historical endpoints and noisy denoising states. This formulation aligns training attention with inference-time extrapolation and allows downstream chunk losses to supervise the history representations that future predictions rely on. We further propose Consistency Model Group Relative Policy Optimization (CM-GRPO), which reformulates consistency sampling steps as conditional Gaussian transitions and applies online reinforcement learning (RL) directly to this kernel, avoiding the Euler-Maruyama auxiliary processes adopted in prior flow-model RL formulations. Experiments show that RAVEN surpasses recent causal video distillation baselines across quality, semantic, and dynamic-degree evaluations, and CM-GRPO yields further improvement when combined with RAVEN.
Key Contributions
1. RAVEN training-time test framework: repacks each autoregressive self rollout into an interleaved sequence of clean historical endpoints and noisy denoising states, closing the train–inference history distribution gap. 2. Aligned supervision: downstream chunk losses can supervise the history representations on which future predictions depend. 3. CM-GRPO: treats consistency sampling steps as conditional Gaussian transitions and applies online RL directly to this kernel, without Euler-Maruyama auxiliary processes used in earlier flow-model RL methods.
Results
RAVEN outperforms recent causal video distillation baselines on quality, semantic, and dynamic-degree metrics; adding CM-GRPO brings further gains.
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