  Long-form video understanding represents a significant challenge within
computer vision, demanding a model capable of reasoning over long multi-modal
sequences. Motivated by the human cognitive process for long-form video
understanding, we emphasize interactive reasoning and planning over the ability
to process lengthy visual inputs. We introduce a novel agent-based system,
VideoAgent, that employs a large language model as a central agent to
iteratively identify and compile crucial information to answer a question, with
vision-language foundation models serving as tools to translate and retrieve
visual information. Evaluated on the challenging EgoSchema and NExT-QA
benchmarks, VideoAgent achieves 54.1% and 71.3% zero-shot accuracy with only
8.4 and 8.2 frames used on average. These results demonstrate superior
effectiveness and efficiency of our method over the current state-of-the-art
methods, highlighting the potential of agent-based approaches in advancing
long-form video understanding.
