When and What: Diffusion-Grounded VideoLLM with Entity Aware Segmentation for Long Video Understanding

Fuente: arXiv
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Autori principali: Fang, Pengcheng, Chen, Yuxia, Guo, Rui
Natura: Preprint
Pubblicazione: 2025
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author Fang, Pengcheng
Chen, Yuxia
Guo, Rui
author_facet Fang, Pengcheng
Chen, Yuxia
Guo, Rui
contents Understanding videos requires more than answering open ended questions, it demands the ability to pinpoint when events occur and how entities interact across time. While recent Video LLMs have achieved remarkable progress in holistic reasoning, they remain coarse in temporal perception: timestamps are encoded only implicitly, frame level features are weak in capturing continuity, and language vision alignment often drifts from the entities of interest. In this paper, we present Grounded VideoDiT, a Video LLM designed to overcome these limitations by introducing three key innovations. First, a Diffusion Temporal Latent (DTL) encoder enhances boundary sensitivity and maintains temporal consistency. Second, object grounded representations explicitly bind query entities to localized visual evidence, strengthening alignment. Third, a mixed token scheme with discrete temporal tokens provides explicit timestamp modeling, enabling fine grained temporal reasoning. Together, these designs equip Grounded VideoDiT with robust grounding capabilities, as validated by state of the art results on Charades STA, NExT GQA, and multiple VideoQA benchmarks.
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id arxiv_https___arxiv_org_abs_2508_15641
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle When and What: Diffusion-Grounded VideoLLM with Entity Aware Segmentation for Long Video Understanding
Fang, Pengcheng
Chen, Yuxia
Guo, Rui
Computer Vision and Pattern Recognition
Understanding videos requires more than answering open ended questions, it demands the ability to pinpoint when events occur and how entities interact across time. While recent Video LLMs have achieved remarkable progress in holistic reasoning, they remain coarse in temporal perception: timestamps are encoded only implicitly, frame level features are weak in capturing continuity, and language vision alignment often drifts from the entities of interest. In this paper, we present Grounded VideoDiT, a Video LLM designed to overcome these limitations by introducing three key innovations. First, a Diffusion Temporal Latent (DTL) encoder enhances boundary sensitivity and maintains temporal consistency. Second, object grounded representations explicitly bind query entities to localized visual evidence, strengthening alignment. Third, a mixed token scheme with discrete temporal tokens provides explicit timestamp modeling, enabling fine grained temporal reasoning. Together, these designs equip Grounded VideoDiT with robust grounding capabilities, as validated by state of the art results on Charades STA, NExT GQA, and multiple VideoQA benchmarks.
title When and What: Diffusion-Grounded VideoLLM with Entity Aware Segmentation for Long Video Understanding
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2508.15641