Adaptive Keyframe Sampling for Long Video Understanding

Fuente: arXiv
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Autori principali: Tang, Xi, Qiu, Jihao, Xie, Lingxi, Tian, Yunjie, Jiao, Jianbin, Ye, Qixiang
Natura: Preprint
Pubblicazione: 2025
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author Tang, Xi
Qiu, Jihao
Xie, Lingxi
Tian, Yunjie
Jiao, Jianbin
Ye, Qixiang
author_facet Tang, Xi
Qiu, Jihao
Xie, Lingxi
Tian, Yunjie
Jiao, Jianbin
Ye, Qixiang
contents Multimodal large language models (MLLMs) have enabled open-world visual understanding by injecting visual input as extra tokens into large language models (LLMs) as contexts. However, when the visual input changes from a single image to a long video, the above paradigm encounters difficulty because the vast amount of video tokens has significantly exceeded the maximal capacity of MLLMs. Therefore, existing video-based MLLMs are mostly established upon sampling a small portion of tokens from input data, which can cause key information to be lost and thus produce incorrect answers. This paper presents a simple yet effective algorithm named Adaptive Keyframe Sampling (AKS). It inserts a plug-and-play module known as keyframe selection, which aims to maximize the useful information with a fixed number of video tokens. We formulate keyframe selection as an optimization involving (1) the relevance between the keyframes and the prompt, and (2) the coverage of the keyframes over the video, and present an adaptive algorithm to approximate the best solution. Experiments on two long video understanding benchmarks validate that Adaptive Keyframe Sampling improves video QA accuracy (beyond strong baselines) upon selecting informative keyframes. Our study reveals the importance of information pre-filtering in video-based MLLMs. Code is available at https://github.com/ncTimTang/AKS.
format Preprint
id arxiv_https___arxiv_org_abs_2502_21271
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Adaptive Keyframe Sampling for Long Video Understanding
Tang, Xi
Qiu, Jihao
Xie, Lingxi
Tian, Yunjie
Jiao, Jianbin
Ye, Qixiang
Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
Multimodal large language models (MLLMs) have enabled open-world visual understanding by injecting visual input as extra tokens into large language models (LLMs) as contexts. However, when the visual input changes from a single image to a long video, the above paradigm encounters difficulty because the vast amount of video tokens has significantly exceeded the maximal capacity of MLLMs. Therefore, existing video-based MLLMs are mostly established upon sampling a small portion of tokens from input data, which can cause key information to be lost and thus produce incorrect answers. This paper presents a simple yet effective algorithm named Adaptive Keyframe Sampling (AKS). It inserts a plug-and-play module known as keyframe selection, which aims to maximize the useful information with a fixed number of video tokens. We formulate keyframe selection as an optimization involving (1) the relevance between the keyframes and the prompt, and (2) the coverage of the keyframes over the video, and present an adaptive algorithm to approximate the best solution. Experiments on two long video understanding benchmarks validate that Adaptive Keyframe Sampling improves video QA accuracy (beyond strong baselines) upon selecting informative keyframes. Our study reveals the importance of information pre-filtering in video-based MLLMs. Code is available at https://github.com/ncTimTang/AKS.
title Adaptive Keyframe Sampling for Long Video Understanding
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2502.21271