CapMem: A Benchmark for Caption-Based Episodic Memory in Egocentric Video

Dingli Liang, Yiqiao Xie, Yukai Huang, Zhaokai Wang, Weitong Cai, Guangwen Feng, Jifei Song, Zhensong Zhang, Hang Zhang


Abstract
Wearable assistants require episodic memory over egocentric video, yet current vision-language models face bounded frame budgets, growing visual-token costs, and long-context retrieval failures. Under these practical constraints, we study whether textual captions can serve as reusable episodic memory. We define the Episodic Memory Video Caption QA task and introduce CapMem, a human-annotated benchmark with 75 videos totaling 33.7 hours, and 1,000 multiple-choice questions across 16 scenarios. On long videos (>20 min), full-coverage CaptionQA with 30s and 60s caption windows outperforms direct VideoQA for 10/12 and 8/12 models, respectively. On the same video subset, a matched-frame control across six Qwen models retains mean accuracy gains of 3.22 and 2.55 points, respectively. Our caption-guided retrieve-and-verify harness further improves accuracy by up to 5.3 points. These results support the effectiveness of caption memory for episodic reasoning over long egocentric video.
Anthology ID:
2026.emnlp-industry.233
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
3888–3914
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.233/
DOI:
Bibkey:
Cite (ACL):
Dingli Liang, Yiqiao Xie, Yukai Huang, Zhaokai Wang, Weitong Cai, Guangwen Feng, Jifei Song, Zhensong Zhang, and Hang Zhang. 2026. CapMem: A Benchmark for Caption-Based Episodic Memory in Egocentric Video. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 3888–3914, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CapMem: A Benchmark for Caption-Based Episodic Memory in Egocentric Video (Liang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.233.pdf