SPIRAL: Self-Evolving Action-Conditioned Video Generation via Reflective Planning Agents
Organizations: Zhejiang University · KnowledgeXLab at Shanghai AI Lab · National University of Singapore · Chinese Academy of Sciences ·
Abstract
Long-horizon action-conditioned video generation aims to synthesize temporally coherent videos that follow complex action instructions over extended horizons, requiring procedural ordering, persistent action execution, and scene consistency beyond conventional TI2V's short-term fidelity. Existing single-shot video generation models typically operate in an open-loop manner, leading to incomplete action execution, hallucinated motions, and temporal drift. To address this, we propose SPIRAL, a closed-loop framework that performs sequential planning and iterative reflection for action-conditioned long-horizon video generation. Specifically, SPIRAL instantiates a think-act-reflect process: a PlanAgent decomposes high-level goals into sub-actions, which condition a VideoGenerator to synthesize each segment alongside a memory context, while a CriticAgent evaluates intermediate video segments to provide corrective feedback for iterative refinement. This closed-loop design further supports self-evolution by utilizing PlanAgent-proposed actions and CriticAgent-derived rewards for GRPO-based post-training to enhance the video generator's long-horizon consistency. Moreover, we introduce ActVideoGen-Dataset for task-specific training, and establish ActVideoGen-Bench as a dedicated evaluation suite for measuring action quality and temporal coherence. Experiments across multiple TI2V backbones alongside the self-evolving strategy show consistent gains on ActVideoGen-Bench and VBench, demonstrating the effectiveness of SPIRAL.
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Supplementary material from the paper’s appendix.
Appendix
| Parameter | SFT | DPO | Description |
| Optimization & Training Strategy | |||
| Base model | Qwen3-VL-8B-Thinking | Backbone vision-language model | |
| Learning rate | Peak learning rate for AdamW | ||
| LR scheduler | Cosine | Cosine | Decay schedule type |
| Warmup ratio | 0.1 | 0.1 | Ratio of warmup steps |
| Max epochs | 3.0 | 3.0 | Number of training epochs |
| Parameter | SFT | RM | Description |
| Optimization & Training Strategy | |||
| Base model | Qwen3-VL-8B-Instruct | Backbone vision-language model | |
| Learning rate | Peak learning rate for AdamW | ||
| LR scheduler | Cosine | Cosine | Decay schedule type |
| Warmup ratio | 0.1 | 0.1 | Ratio of warmup steps |
| Max epochs | 3.0 | 1.0 | Number of training epochs |
| Setting | Model | Inference Cost | Action Quality | |||||
| Avg. Time (s) | Memory (GB) | Action Completeness | Action Smoothness | Object Interaction | Physical Fidelity | Overall Quality | ||
| Single-Shot Baseline | LongLive-2B [ 14 ] | 8 | 28 | 0.273 | 0.646 | 0.776 | 0.808 | 0.626 |
| PlanAgent (Ours) | Qwen3-VL-8B [ 24 ] | 4 | 19 | - | - | - | - | - |
| VideoGenerator (Per-step) | LongLive-2B [ 14 ] | 8 | 28 | - | - | - | - | - |
| CriticAgent (Per-step) | Qwen3-VL-8B [ 24 ] | 7 | 22 | - | - | - | - | - |
| SPIRAL (T=3, Retry=1) | Plan+Gen+Critic | 49 | 69 | 0.721 +44.8% | 0.902 +25.6% | 0.860 +8.4% | 0.924 +11.6% | 0.852 +22.6% |
Action-Conditioned Video Generation
Action-conditioned video generation creates videos whose motion and scene changes are guided by controls, actions, or interaction signals.
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