Reinforcement Learning with Inverse Rewards for World Model Post-training
TLDR
Proposes RLIR, a post-training framework using inverse rewards from an Inverse Dynamics Model to improve action-following in video world models, achieving 5-10% gains.
Reasoning
The paper addresses a clear gap in world model post-training with a novel reward formulation, showing empirical gains across paradigms. However, the abstract lacks details on baselines, datasets, and limitations, and the reliance on inverse dynamics may introduce biases.
Read-first score
Read-first score 61.1, weighted from topical fit, citation, graph, method, reproducibility, and recency signals. Original total remains 57.
Field roles
Rank sensitivity
Stability: volatile; rank range: 536.
Keyword Scores
Deep Analysis
Innovations
- Proposes RLIR, a post-training framework that uses an Inverse Dynamics Model to recover input actions from generated videos, producing verifiable reward signals without large-scale preference annotations or rule-based verifiers.
- First post-training method specifically designed to enhance action-following in video world models.
- Maps high-dimensional video modality to low-dimensional action space for objective reward, enabling reinforcement learning optimization via Group Relative Policy Optimization.
Methodology
RLIR post-trains pre-trained world models by generating a video from an action sequence, then using an Inverse Dynamics Model to predict the action from the video. The similarity between predicted and ground-truth actions provides a reward, which is optimized with Group Relative Policy Optimization. The method is applied across autoregressive and diffusion world model paradigms.
Key Results
Achieves 5-10% gains in action-following accuracy, up to 10% improvements in visual quality, and higher human preference scores compared to existing methods.