Video-in-the-Loop: Span-Grounded Long Video QA with Interleaved Reasoning

Fuente: arXiv
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Auteurs principaux: Wang, Chendong, Bai, Donglin, Yang, Yifan, Jin, Xiao, Zhang, Anlan, Wang, Rui, Jiang, Shiqi, Yang, Yuqing, Wu, Hao, Dai, Qi, Luo, Chong, Cao, Ting, Qiu, Lili, Banerjee, Suman
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Publié: 2025
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author Wang, Chendong
Bai, Donglin
Yang, Yifan
Jin, Xiao
Zhang, Anlan
Wang, Rui
Jiang, Shiqi
Yang, Yuqing
Wu, Hao
Dai, Qi
Luo, Chong
Cao, Ting
Qiu, Lili
Banerjee, Suman
author_facet Wang, Chendong
Bai, Donglin
Yang, Yifan
Jin, Xiao
Zhang, Anlan
Wang, Rui
Jiang, Shiqi
Yang, Yuqing
Wu, Hao
Dai, Qi
Luo, Chong
Cao, Ting
Qiu, Lili
Banerjee, Suman
contents We present \emph{Video-in-the-Loop} (ViTL), a two-stage long-video QA framework that preserves a fixed token budget by first \emph{localizing} question-relevant interval(s) with a low-fps skim and then \emph{answering} via span-aware reallocation of visual tokens at higher effective frame rate, emitting an interleaved output with both spans and the final option for direct attribution. We also introduce \dataname{}, which converts description based event graphs into \emph{span-grounded} multiple-choice QA by pairing each question with \emph{ground-truth} time span(s) and related reasoning. ViTL is trained end-to-end with an interleaved group-relative objective that couples temporal IoU for localization with answer correctness, allowing credit to flow from answers back to spans without increasing compute. Under fixed token budgets, ViTL attains up to 8.6% with 50% less frame input on long-video QA and temporal grounding (e.g., Charades-STA, ActivityNet-Captions) and ablations show that span-aware token reallocation consistently surpasses uniform sampling. Together, \dataname{} and ViTL provide an interpretable, compute-efficient recipe for scalable long-video QA.
format Preprint
id arxiv_https___arxiv_org_abs_2510_04022
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Video-in-the-Loop: Span-Grounded Long Video QA with Interleaved Reasoning
Wang, Chendong
Bai, Donglin
Yang, Yifan
Jin, Xiao
Zhang, Anlan
Wang, Rui
Jiang, Shiqi
Yang, Yuqing
Wu, Hao
Dai, Qi
Luo, Chong
Cao, Ting
Qiu, Lili
Banerjee, Suman
Computer Vision and Pattern Recognition
We present \emph{Video-in-the-Loop} (ViTL), a two-stage long-video QA framework that preserves a fixed token budget by first \emph{localizing} question-relevant interval(s) with a low-fps skim and then \emph{answering} via span-aware reallocation of visual tokens at higher effective frame rate, emitting an interleaved output with both spans and the final option for direct attribution. We also introduce \dataname{}, which converts description based event graphs into \emph{span-grounded} multiple-choice QA by pairing each question with \emph{ground-truth} time span(s) and related reasoning. ViTL is trained end-to-end with an interleaved group-relative objective that couples temporal IoU for localization with answer correctness, allowing credit to flow from answers back to spans without increasing compute. Under fixed token budgets, ViTL attains up to 8.6% with 50% less frame input on long-video QA and temporal grounding (e.g., Charades-STA, ActivityNet-Captions) and ablations show that span-aware token reallocation consistently surpasses uniform sampling. Together, \dataname{} and ViTL provide an interpretable, compute-efficient recipe for scalable long-video QA.
title Video-in-the-Loop: Span-Grounded Long Video QA with Interleaved Reasoning
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2510.04022