Free Video-LLM: Prompt-guided Visual Perception for Efficient Training-free Video LLMs
This work addresses the inference efficiency bottleneck for video understanding tasks, offering a more resource-efficient alternative to training-based models, though it is incremental as it builds on existing pre-trained image-LLMs.
The paper tackles the computational inefficiency of training-free video large language models by introducing a prompt-guided visual perception framework that reduces visual tokens through temporal sampling and spatial cropping, achieving competitive performance on video question-answering benchmarks with significantly fewer tokens.
Vision-language large models have achieved remarkable success in various multi-modal tasks, yet applying them to video understanding remains challenging due to the inherent complexity and computational demands of video data. While training-based video-LLMs deliver high performance, they often require substantial resources for training and inference. Conversely, training-free approaches offer a more efficient alternative by adapting pre-trained image-LLMs models for video tasks without additional training, but they face inference efficiency bottlenecks due to the large number of visual tokens generated from video frames. In this work, we present a novel prompt-guided visual perception framework (abbreviated as Free Video-LLM) for efficient inference of training-free video LLMs. The proposed framework decouples spatial-temporal dimension and performs temporal frame sampling and spatial RoI cropping respectively based on task-specific prompts. Our method effectively reduces the number of visual tokens while maintaining high performance across multiple video question-answering benchmarks. Extensive experiments demonstrate that our approach achieves competitive results with significantly fewer tokens, offering an optimal trade-off between accuracy and computational efficiency compared to state-of-the-art video LLMs. The code will be available at https://github.com/contrastive/FreeVideoLLM.