ARC-Chapter: Structuring Hour-Long Videos into Navigable Chapters and Hierarchical Summaries

TL;DR

ARC-Chapter is a large-scale, hierarchical video chaptering model trained on over a million long videos, significantly improving chapter segmentation accuracy and transferability to downstream tasks through novel data and evaluation methods.

Contribution

It introduces the first large-scale bilingual hierarchical video chaptering model with a new dataset and evaluation metric, advancing long video content structuring.

Findings

Achieves 14.0% higher F1 score over previous methods.

Demonstrates strong transferability to dense video captioning.

Shows performance improvements with increased data scale and label richness.

Abstract

The proliferation of hour-long videos (e.g., lectures, podcasts, documentaries) has intensified demand for efficient content structuring. However, existing approaches are constrained by small-scale training with annotations that are typical short and coarse, restricting generalization to nuanced transitions in long videos. We introduce ARC-Chapter, the first large-scale video chaptering model trained on over million-level long video chapters, featuring bilingual, temporally grounded, and hierarchical chapter annotations. To achieve this goal, we curated a bilingual English-Chinese chapter dataset via a structured pipeline that unifies ASR transcripts, scene texts, visual captions into multi-level annotations, from short title to long summaries. We demonstrate clear performance improvements with data scaling, both in data volume and label intensity. Moreover, we design a new evaluation metric termed GRACE, which incorporates many-to-one segment overlaps and semantic similarity, better reflecting real-world chaptering flexibility. Extensive experiments demonstrate that ARC-Chapter establishes a new state-of-the-art by a significant margin, outperforming the previous best by 14.0% in F1 score and 11.3% in SODA score. Moreover, ARC-Chapter shows excellent transferability, improving the state-of-the-art on downstream tasks like dense video captioning on YouCook2.