Distorted or Fabricated? A Survey on Hallucination in Video LLMs

Yiyang Huang, Yitian Zhang, Yizhou Wang, Mingyuan Zhang, Liang Shi, Huimin Zeng, Yun Fu


Abstract
Despite significant progress in video-language modeling, hallucinations remain a persistent challenge in Video Large Language Models (Vid-LLMs), referring to outputs that appear plausible yet contradict the content of the input video. This survey presents a comprehensive analysis of hallucinations in Vid-LLMs and introduces a systematic taxonomy that categorizes them into two core types: dynamic distortion and content fabrication, each comprising two subtypes with representative cases. Building on this taxonomy, we review recent advances in the evaluation and mitigation of hallucinations, covering key benchmarks, metrics, and intervention strategies. We further analyze the root causes of dynamic distortion and content fabrication, which often result from limited capacity for temporal representation and insufficient visual grounding. These insights inform several promising directions for future work, including the development of motion-aware visual encoders and the integration of counterfactual learning techniques. This survey consolidates scattered progress to foster a systematic understanding of hallucinations in Vid-LLMs, laying the groundwork for building robust and reliable video-language systems.
Anthology ID:
2026.findings-acl.1325
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
26599–26611
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1325/
DOI:
Bibkey:
Cite (ACL):
Yiyang Huang, Yitian Zhang, Yizhou Wang, Mingyuan Zhang, Liang Shi, Huimin Zeng, and Yun Fu. 2026. Distorted or Fabricated? A Survey on Hallucination in Video LLMs. In Findings of the Association for Computational Linguistics: ACL 2026, pages 26599–26611, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Distorted or Fabricated? A Survey on Hallucination in Video LLMs (Huang et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1325.pdf
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