Where to Focus: Query-Modulated Multimodal Keyframe Selection for Long Video Understanding

Fuente: arXiv
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Auteurs principaux: Wang, Shaoguang, Guo, Weiyu, Chen, Ziyang, Hu, Xuming, Xiong, Hui
Format: Preprint
Publié: 2026
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author Wang, Shaoguang
Guo, Weiyu
Chen, Ziyang
Hu, Xuming
Xiong, Hui
author_facet Wang, Shaoguang
Guo, Weiyu
Chen, Ziyang
Hu, Xuming
Xiong, Hui
contents Long video understanding remains a formidable challenge for Multimodal Large Language Models (MLLMs) due to the prohibitive computational cost of processing dense frame sequences. Prevailing solutions, which select a keyframe subset, typically rely on either a single visual-centric metric (e.g., CLIP similarity) or a static fusion of heuristic scores. This ``one-size-fits-all'' paradigm frequently fails: visual-only metrics are ineffective for plot-driven narrative queries, while indiscriminately incorporating textual scores introduces severe ``modal noise'' for purely visual tasks. To break this bottleneck, we propose Q-Gate, a plug-and-play and training-free framework that treats keyframe selection as a dynamic modality routing problem. We decouple the retrieval process into three lightweight expert streams: Visual Grounding for local details, Global Matching for scene semantics, and Contextual Alignment for subtitle-driven narratives. Crucially, Q-Gate introduces a Query-Modulated Gating Mechanism that leverages the in-context reasoning of an LLM to assess the query's intent and dynamically allocate attention weights across the experts. This mechanism intelligently activates necessary modalities while ``muting'' irrelevant ones, thereby maximizing the signal-to-noise ratio. Extensive experiments on LongVideoBench and Video-MME across multiple MLLM backbones demonstrate that Q-Gate substantially outperforms state-of-the-art baselines. By effectively suppressing modality-specific noise, it provides a robust, highly interpretable solution for scalable video reasoning.
format Preprint
id arxiv_https___arxiv_org_abs_2604_17422
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Where to Focus: Query-Modulated Multimodal Keyframe Selection for Long Video Understanding
Wang, Shaoguang
Guo, Weiyu
Chen, Ziyang
Hu, Xuming
Xiong, Hui
Computer Vision and Pattern Recognition
Multimedia
Long video understanding remains a formidable challenge for Multimodal Large Language Models (MLLMs) due to the prohibitive computational cost of processing dense frame sequences. Prevailing solutions, which select a keyframe subset, typically rely on either a single visual-centric metric (e.g., CLIP similarity) or a static fusion of heuristic scores. This ``one-size-fits-all'' paradigm frequently fails: visual-only metrics are ineffective for plot-driven narrative queries, while indiscriminately incorporating textual scores introduces severe ``modal noise'' for purely visual tasks. To break this bottleneck, we propose Q-Gate, a plug-and-play and training-free framework that treats keyframe selection as a dynamic modality routing problem. We decouple the retrieval process into three lightweight expert streams: Visual Grounding for local details, Global Matching for scene semantics, and Contextual Alignment for subtitle-driven narratives. Crucially, Q-Gate introduces a Query-Modulated Gating Mechanism that leverages the in-context reasoning of an LLM to assess the query's intent and dynamically allocate attention weights across the experts. This mechanism intelligently activates necessary modalities while ``muting'' irrelevant ones, thereby maximizing the signal-to-noise ratio. Extensive experiments on LongVideoBench and Video-MME across multiple MLLM backbones demonstrate that Q-Gate substantially outperforms state-of-the-art baselines. By effectively suppressing modality-specific noise, it provides a robust, highly interpretable solution for scalable video reasoning.
title Where to Focus: Query-Modulated Multimodal Keyframe Selection for Long Video Understanding
topic Computer Vision and Pattern Recognition
Multimedia
url https://arxiv.org/abs/2604.17422