Breaking Temporal Ambiguity: Linguistic Temporal Knowledge Transfer for Weakly-Supervised Action Localization

Zhilin Li, Shining Wu, Yixin Zhang, Chuandong Cheng, Zilei Wang


Abstract
Weakly-supervised temporal action localization (WS-TAL) remains challenging due to the severe temporal ambiguity inherent in video-level supervision. Existing methods often overfit to highly discriminative snippets, struggling to capture the complete action extent. In this paper, we reconceptualize actions not as isolated events, but as multi-stage action evolutions. To alleviate temporal ambiguity, we propose a novel framework driven by Linguistic Temporal Knowledge Transfer (LTKT) Network, comprising three cohesive modules. First, Temporal Stage Grounding (TSG) leverages explicitly deconstructed LLM descriptions as cross-modal priors, guiding unconstrained visual snippets to anchor their specific evolutionary stages. Second, Temporal Transition Gating (TTG) enforces forward causality on the timeline. By mandating that an execution stage is flanked by historical preparation and future completion, TTG strictly filters static noise to yield refined temporal action scores. Finally, Linguistic Knowledge Transfer (LKT) integrates knowledge distillation and contrastive learning to embed this structural knowledge into the visual backbone. Extensive experiments on THUMOS14, ActivityNet1.2 and ActivityNet1.3 demonstrate that our method achieves state-of-the-art performance.
Anthology ID:
2026.emnlp-main.1350
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
30771–30787
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1350/
DOI:
Bibkey:
Cite (ACL):
Zhilin Li, Shining Wu, Yixin Zhang, Chuandong Cheng, and Zilei Wang. 2026. Breaking Temporal Ambiguity: Linguistic Temporal Knowledge Transfer for Weakly-Supervised Action Localization. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 30771–30787, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Breaking Temporal Ambiguity: Linguistic Temporal Knowledge Transfer for Weakly-Supervised Action Localization (Li et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1350.pdf