AVATAR: Reinforcement Learning to See, Hear, and Reason Over Video

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Main Authors: Kulkarni, Yogesh, Fazli, Pooyan
Format: Preprint
Published: 2025
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author Kulkarni, Yogesh
Fazli, Pooyan
author_facet Kulkarni, Yogesh
Fazli, Pooyan
contents Multimodal reasoning over long-horizon video is challenging due to the need for precise spatiotemporal fusion and alignment across modalities. While recent methods such as Group Relative Policy Optimization (GRPO) have shown promise in this domain, they suffer from three key limitations: (1) data inefficiency from their on-policy design, (2) a vanishing advantage problem, where identical or near-identical rewards within a group eliminate the learning signal by producing zero-valued advantages, and (3) uniform credit assignment that fails to emphasize critical reasoning steps. We introduce $\textbf{AVATAR}$ ($\textbf{A}$udio-$\textbf{V}$ideo $\textbf{A}$gen$\textbf{t}$ for $\textbf{A}$lignment and $\textbf{R}$easoning), a framework that addresses these limitations through two core components: (1) an off-policy training architecture that improves sample efficiency and resolves vanishing advantages by reusing past experiences with greater reward diversity, and (2) Temporal Advantage Shaping (TAS), a credit assignment strategy that emphasizes early (planning) and late (synthesis) reasoning phases. $\textbf{AVATAR}$ achieves strong performance across various benchmarks, outperforming the Qwen2.5-Omni baseline by $\mathbf{+5.4}$ on MMVU, $\mathbf{+4.9}$ on OmniBench, and $\mathbf{+4.5}$ on Video-Holmes. Furthermore, it surpasses standard GRPO by $\mathbf{+3.7}$ on OmniBench and $\mathbf{+1.9}$ on Video-Holmes, while demonstrating $\textbf{$5$$\times$ sample efficiency}$, requiring $80\%$ fewer generated completions to reach target performance.
format Preprint
id arxiv_https___arxiv_org_abs_2508_03100
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle AVATAR: Reinforcement Learning to See, Hear, and Reason Over Video
Kulkarni, Yogesh
Fazli, Pooyan
Computer Vision and Pattern Recognition
Multimodal reasoning over long-horizon video is challenging due to the need for precise spatiotemporal fusion and alignment across modalities. While recent methods such as Group Relative Policy Optimization (GRPO) have shown promise in this domain, they suffer from three key limitations: (1) data inefficiency from their on-policy design, (2) a vanishing advantage problem, where identical or near-identical rewards within a group eliminate the learning signal by producing zero-valued advantages, and (3) uniform credit assignment that fails to emphasize critical reasoning steps. We introduce $\textbf{AVATAR}$ ($\textbf{A}$udio-$\textbf{V}$ideo $\textbf{A}$gen$\textbf{t}$ for $\textbf{A}$lignment and $\textbf{R}$easoning), a framework that addresses these limitations through two core components: (1) an off-policy training architecture that improves sample efficiency and resolves vanishing advantages by reusing past experiences with greater reward diversity, and (2) Temporal Advantage Shaping (TAS), a credit assignment strategy that emphasizes early (planning) and late (synthesis) reasoning phases. $\textbf{AVATAR}$ achieves strong performance across various benchmarks, outperforming the Qwen2.5-Omni baseline by $\mathbf{+5.4}$ on MMVU, $\mathbf{+4.9}$ on OmniBench, and $\mathbf{+4.5}$ on Video-Holmes. Furthermore, it surpasses standard GRPO by $\mathbf{+3.7}$ on OmniBench and $\mathbf{+1.9}$ on Video-Holmes, while demonstrating $\textbf{$5$$\times$ sample efficiency}$, requiring $80\%$ fewer generated completions to reach target performance.
title AVATAR: Reinforcement Learning to See, Hear, and Reason Over Video
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2508.03100