Untrimmed videos have interrelated events, dependencies, context, overlapping events, object-object interactions, domain specificity, and other semantics that are worth highlighting while describing a video in natural language. Owing to such a vast diversity, a single sentence can only correctly describe a portion of the video. Dense Video Captioning (DVC) aims at detecting and describing different events in a given video. The term DVC originated in the 2017 ActivityNet challenge, after which considerable effort has been made to address the challenge. Dense Video Captioning is divided into three sub-tasks: (1) Video Feature Extraction (VFE), (2) Temporal Event Localization (TEL), and (3) Dense Caption Generation (DCG). This review aims to discuss all the studies that claim to perform DVC along with its sub-tasks and summarize their results. We also discuss all the datasets that have been used for DVC. Lastly, we highlight some emerging challenges and future trends in the field.

使用Dense Video Captioning (DVC)技术，本文综述了在描述长视频时需要突出显示的相互关联事件、依赖关系、上下文、重叠事件、物体间的相互作用以及领域特定性等语义，同时讨论了DVC的子任务和它们的结果，涵盖视频特征提取、时间事件定位和密集字幕生成，还探讨了DVC所使用的数据集以及领域中的新挑战和未来趋势。

密集视频字幕：技术、数据集和评估协议综述