From Captions to Keyframes: KeyScore for Multimodal Frame Scoring and Video-Language Understanding

Fuente: arXiv
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Main Authors: Lin, Shih-Yao, Paul, Sibendu, Chen, Caren
Format: Preprint
Published: 2025
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author Lin, Shih-Yao
Paul, Sibendu
Chen, Caren
author_facet Lin, Shih-Yao
Paul, Sibendu
Chen, Caren
contents Selecting informative keyframes is critical for efficient video understanding, yet existing approaches often rely on heuristics, ignore semantics, or produce redundant frames. We propose KeyScore, a caption-aware frame scoring method that combines three complementary signals: semantic similarity to captions, temporal representativeness, and contextual drop impact. Applied to large-scale video-caption datasets, KeyScore generates frame-level importance scores that enable training keyframe extractors or guiding video-language models. To support this, we also propose STACFP, a Spatio-Temporal Adaptive Clustering method that generates diverse and compact frame proposals across long videos. Together, KeyScore and STACFP reduce uninformative frames while preserving critical content, resulting in faster and more accurate inference. Our experiments on three standard video-language benchmarks (MSRVTT, MSVD, DiDeMo) show that combining STACFP and KeyScore enables up to 99% frame reduction compared to full-frame processing, while outperforming uniform 8-frame encoders in video-text retrieval, keyframe extraction, and action recognition tasks. By focusing on semantically relevant frames, our method enhances both efficiency and performance, enabling scalable and caption-grounded video understanding.
format Preprint
id arxiv_https___arxiv_org_abs_2510_06509
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle From Captions to Keyframes: KeyScore for Multimodal Frame Scoring and Video-Language Understanding
Lin, Shih-Yao
Paul, Sibendu
Chen, Caren
Computer Vision and Pattern Recognition
Selecting informative keyframes is critical for efficient video understanding, yet existing approaches often rely on heuristics, ignore semantics, or produce redundant frames. We propose KeyScore, a caption-aware frame scoring method that combines three complementary signals: semantic similarity to captions, temporal representativeness, and contextual drop impact. Applied to large-scale video-caption datasets, KeyScore generates frame-level importance scores that enable training keyframe extractors or guiding video-language models. To support this, we also propose STACFP, a Spatio-Temporal Adaptive Clustering method that generates diverse and compact frame proposals across long videos. Together, KeyScore and STACFP reduce uninformative frames while preserving critical content, resulting in faster and more accurate inference. Our experiments on three standard video-language benchmarks (MSRVTT, MSVD, DiDeMo) show that combining STACFP and KeyScore enables up to 99% frame reduction compared to full-frame processing, while outperforming uniform 8-frame encoders in video-text retrieval, keyframe extraction, and action recognition tasks. By focusing on semantically relevant frames, our method enhances both efficiency and performance, enabling scalable and caption-grounded video understanding.
title From Captions to Keyframes: KeyScore for Multimodal Frame Scoring and Video-Language Understanding
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2510.06509