Unified Spatio-Temporal Token Scoring for Efficient Video VLMs

Fuente: arXiv
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Autori principali: Zhang, Jianrui, Yang, Yue, Tripathi, Rohun, Han, Winson, Krishna, Ranjay, Clark, Christopher, Lee, Yong Jae, Lee, Sangho
Natura: Preprint
Pubblicazione: 2026
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author Zhang, Jianrui
Yang, Yue
Tripathi, Rohun
Han, Winson
Krishna, Ranjay
Clark, Christopher
Lee, Yong Jae
Lee, Sangho
author_facet Zhang, Jianrui
Yang, Yue
Tripathi, Rohun
Han, Winson
Krishna, Ranjay
Clark, Christopher
Lee, Yong Jae
Lee, Sangho
contents Token pruning is essential for enhancing the computational efficiency of vision-language models (VLMs), particularly for video-based tasks where temporal redundancy is prevalent. Prior approaches typically prune tokens either (1) within the vision transformer (ViT) exclusively for unimodal perception tasks such as action recognition and object segmentation, without adapting to downstream vision-language tasks; or (2) only within the LLM while leaving the ViT output intact, often requiring complex text-conditioned token selection mechanisms. In this paper, we introduce Spatio-Temporal Token Scoring (STTS), a simple and lightweight module that prunes vision tokens across both the ViT and the LLM without text conditioning or token merging, and is fully compatible with end-to-end training. By learning how to score temporally via an auxiliary loss and spatially via LLM downstream gradients, aided by our efficient packing algorithm, STTS prunes 50% of vision tokens throughout the entire architecture, resulting in a 62% improvement in efficiency during both training and inference with only a 0.7% drop in average performance across 13 short and long video QA tasks. Efficiency gains increase with more sampled frames per video. Applying test-time scaling for long-video QA further yields performance gains of 0.5-1% compared to the baseline. Overall, STTS represents a novel, simple yet effective technique for unified, architecture-wide vision token pruning.
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id arxiv_https___arxiv_org_abs_2603_18004
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Unified Spatio-Temporal Token Scoring for Efficient Video VLMs
Zhang, Jianrui
Yang, Yue
Tripathi, Rohun
Han, Winson
Krishna, Ranjay
Clark, Christopher
Lee, Yong Jae
Lee, Sangho
Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
Token pruning is essential for enhancing the computational efficiency of vision-language models (VLMs), particularly for video-based tasks where temporal redundancy is prevalent. Prior approaches typically prune tokens either (1) within the vision transformer (ViT) exclusively for unimodal perception tasks such as action recognition and object segmentation, without adapting to downstream vision-language tasks; or (2) only within the LLM while leaving the ViT output intact, often requiring complex text-conditioned token selection mechanisms. In this paper, we introduce Spatio-Temporal Token Scoring (STTS), a simple and lightweight module that prunes vision tokens across both the ViT and the LLM without text conditioning or token merging, and is fully compatible with end-to-end training. By learning how to score temporally via an auxiliary loss and spatially via LLM downstream gradients, aided by our efficient packing algorithm, STTS prunes 50% of vision tokens throughout the entire architecture, resulting in a 62% improvement in efficiency during both training and inference with only a 0.7% drop in average performance across 13 short and long video QA tasks. Efficiency gains increase with more sampled frames per video. Applying test-time scaling for long-video QA further yields performance gains of 0.5-1% compared to the baseline. Overall, STTS represents a novel, simple yet effective technique for unified, architecture-wide vision token pruning.
title Unified Spatio-Temporal Token Scoring for Efficient Video VLMs
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2603.18004