EMMA: Event-Driven Multimodal Memory System with Multi-Agent Retrieval

Ruochen Zhao, Jiazheng Kang, Dongying Lin, Gezi Li, Ting Bai


Abstract
Long video understanding requires reasoning over hours of content that far exceed the context window of multimodal large language models (MLLMs). Existing approaches compress video into fixed-length clips, yet events are fragmented and unrelated content is merged, yielding noisy retrieval. To overcome this challenge, we propose EMMA, an Event-driven Multimodal Memory system with Multi-Agent retrieval, which organizes memory around semantic events in three stages: (1) Event segmentation: a dual-stream detector adaptively locates event boundaries by fusing visual semantic drift with spoken transitions, rather than fixed windows. (2) Memory construction: built on the detected events, a three-level hierarchy of raw video, clip-level memory, and event-level memory stores content at progressively higher semantic abstraction. (3) Memory retrieval: a multi-agent framework collaboratively queries this hierarchy through query decomposition, tiered search, evidence validation, and answer generation, narrowing evidence from coarse events to precise clips. Extensive experiments on three challenging benchmarks demonstrate substantial improvements, showing the effectiveness of our event-aligned memory system. Code, prompt templates, and reproduction scripts are available at https://github.com/BAI-LAB/EMMA.
Anthology ID:
2026.findings-emnlp.1256
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
26549–26561
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1256/
DOI:
Bibkey:
Cite (ACL):
Ruochen Zhao, Jiazheng Kang, Dongying Lin, Gezi Li, and Ting Bai. 2026. EMMA: Event-Driven Multimodal Memory System with Multi-Agent Retrieval. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 26549–26561, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
EMMA: Event-Driven Multimodal Memory System with Multi-Agent Retrieval (Zhao et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1256.pdf