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Main Authors: Zheng, Mingzhe, Kong, Weijie, Wu, Yue, Jiang, Dengyang, Ma, Yue, He, Xuanhua, Lin, Bin, Gong, Kaixiong, Zhong, Zhao, Bo, Liefeng, Chen, Qifeng, Yang, Harry
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2603.21872
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author Zheng, Mingzhe
Kong, Weijie
Wu, Yue
Jiang, Dengyang
Ma, Yue
He, Xuanhua
Lin, Bin
Gong, Kaixiong
Zhong, Zhao
Bo, Liefeng
Chen, Qifeng
Yang, Harry
author_facet Zheng, Mingzhe
Kong, Weijie
Wu, Yue
Jiang, Dengyang
Ma, Yue
He, Xuanhua
Lin, Bin
Gong, Kaixiong
Zhong, Zhao
Bo, Liefeng
Chen, Qifeng
Yang, Harry
contents Group Relative Policy Optimization (GRPO) methods for video generation like FlowGRPO remain far less reliable than their counterparts for language models and images. This gap arises because video generation has a complex solution space, and the ODE-to-SDE conversion used for exploration can inject excess noise, lowering rollout quality and making reward estimates less reliable, which destabilizes post-training alignment. To address this problem, we view the pre-trained model as defining a valid video data manifold and formulate the core problem as constraining exploration within the vicinity of this manifold, ensuring that rollout quality is preserved and reward estimates remain reliable. We propose SAGE-GRPO (Stable Alignment via Exploration), which applies constraints at both micro and macro levels. At the micro level, we derive a precise manifold-aware SDE with a logarithmic curvature correction and introduce a gradient norm equalizer to stabilize sampling and updates across timesteps. At the macro level, we use a dual trust region with a periodic moving anchor and stepwise constraints so that the trust region tracks checkpoints that are closer to the manifold and limits long-horizon drift. We evaluate SAGE-GRPO on HunyuanVideo1.5 using the original VideoAlign as the reward model and observe consistent gains over previous methods in VQ, MQ, TA, and visual metrics (CLIPScore, PickScore), demonstrating superior performance in both reward maximization and overall video quality. The code and visual gallery are available at https://dungeonmassster.github.io/SAGE-GRPO-Page/.
format Preprint
id arxiv_https___arxiv_org_abs_2603_21872
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Manifold-Aware Exploration for Reinforcement Learning in Video Generation
Zheng, Mingzhe
Kong, Weijie
Wu, Yue
Jiang, Dengyang
Ma, Yue
He, Xuanhua
Lin, Bin
Gong, Kaixiong
Zhong, Zhao
Bo, Liefeng
Chen, Qifeng
Yang, Harry
Computer Vision and Pattern Recognition
Artificial Intelligence
Group Relative Policy Optimization (GRPO) methods for video generation like FlowGRPO remain far less reliable than their counterparts for language models and images. This gap arises because video generation has a complex solution space, and the ODE-to-SDE conversion used for exploration can inject excess noise, lowering rollout quality and making reward estimates less reliable, which destabilizes post-training alignment. To address this problem, we view the pre-trained model as defining a valid video data manifold and formulate the core problem as constraining exploration within the vicinity of this manifold, ensuring that rollout quality is preserved and reward estimates remain reliable. We propose SAGE-GRPO (Stable Alignment via Exploration), which applies constraints at both micro and macro levels. At the micro level, we derive a precise manifold-aware SDE with a logarithmic curvature correction and introduce a gradient norm equalizer to stabilize sampling and updates across timesteps. At the macro level, we use a dual trust region with a periodic moving anchor and stepwise constraints so that the trust region tracks checkpoints that are closer to the manifold and limits long-horizon drift. We evaluate SAGE-GRPO on HunyuanVideo1.5 using the original VideoAlign as the reward model and observe consistent gains over previous methods in VQ, MQ, TA, and visual metrics (CLIPScore, PickScore), demonstrating superior performance in both reward maximization and overall video quality. The code and visual gallery are available at https://dungeonmassster.github.io/SAGE-GRPO-Page/.
title Manifold-Aware Exploration for Reinforcement Learning in Video Generation
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2603.21872