V-CAST: Video Curvature-Aware Spatio-Temporal Pruning for Efficient Video Large Language Models

Fuente: arXiv
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Autori principali: Lin, Xinying, Liu, Xuyang, Wang, Yiyu, Ma, Teng, Ren, Wenqi
Natura: Preprint
Pubblicazione: 2026
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author Lin, Xinying
Liu, Xuyang
Wang, Yiyu
Ma, Teng
Ren, Wenqi
author_facet Lin, Xinying
Liu, Xuyang
Wang, Yiyu
Ma, Teng
Ren, Wenqi
contents Video large language models (VideoLLMs) show strong capability in video understanding, yet long-context inference is still dominated by massive redundant visual tokens in the prefill stage. We revisit token compression for VideoLLMs under a tight budget and identify a key bottleneck, namely insufficient spatio-temporal information coverage. Existing methods often introduce discontinuous coverage through coarse per-frame allocation or scene segmentation, and token merging can further misalign spatio-temporal coordinates under MRoPE-style discrete (t,h,w) bindings. To address these issues, we propose V-CAST (Video Curvature-Aware Spatio-Temporal Pruning), a training-free, plug-and-play pruning policy for long-context video inference. V-CAST casts token compression as a trajectory approximation problem and introduces a curvature-guided temporal allocation module that routes per-frame token budgets to semantic turns and event boundaries. It further adopts a dual-anchor spatial selection mechanism that preserves high-entropy visual evidence without attention intervention, while keeping retained tokens at their original coordinates to maintain positional alignment. Extensive experiments across multiple VideoLLMs of different architectures and scales demonstrate that V-CAST achieves 98.6% of the original performance, outperforms the second-best method by +1.1% on average, and reduces peak memory and total latency to 86.7% and 86.4% of vanilla Qwen3-VL-8B-Instruct.
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id arxiv_https___arxiv_org_abs_2603_27650
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle V-CAST: Video Curvature-Aware Spatio-Temporal Pruning for Efficient Video Large Language Models
Lin, Xinying
Liu, Xuyang
Wang, Yiyu
Ma, Teng
Ren, Wenqi
Computer Vision and Pattern Recognition
Video large language models (VideoLLMs) show strong capability in video understanding, yet long-context inference is still dominated by massive redundant visual tokens in the prefill stage. We revisit token compression for VideoLLMs under a tight budget and identify a key bottleneck, namely insufficient spatio-temporal information coverage. Existing methods often introduce discontinuous coverage through coarse per-frame allocation or scene segmentation, and token merging can further misalign spatio-temporal coordinates under MRoPE-style discrete (t,h,w) bindings. To address these issues, we propose V-CAST (Video Curvature-Aware Spatio-Temporal Pruning), a training-free, plug-and-play pruning policy for long-context video inference. V-CAST casts token compression as a trajectory approximation problem and introduces a curvature-guided temporal allocation module that routes per-frame token budgets to semantic turns and event boundaries. It further adopts a dual-anchor spatial selection mechanism that preserves high-entropy visual evidence without attention intervention, while keeping retained tokens at their original coordinates to maintain positional alignment. Extensive experiments across multiple VideoLLMs of different architectures and scales demonstrate that V-CAST achieves 98.6% of the original performance, outperforms the second-best method by +1.1% on average, and reduces peak memory and total latency to 86.7% and 86.4% of vanilla Qwen3-VL-8B-Instruct.
title V-CAST: Video Curvature-Aware Spatio-Temporal Pruning for Efficient Video Large Language Models
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2603.27650