Temporal Contrastive Decoding: A Training-Free Method for Large Audio-Language Models

Yanda Li, Yuhan Liu, Zirui Song, Yunchao Wei, Martin Tak\'a\v{c}, Salem Lahlou


Abstract
Large audio-language models (LALMs) generalize across speech, sound, and music, but unified decoders can exhibit a temporal smoothing bias: transient acoustic cues may be underutilized in favor of temporally smooth context that is better supported by language priors, leading to less specific audio-grounded outputs. We propose Temporal Contrastive Decoding (TCD), a training-free decoding method for unified LALMs that mitigates this effect at inference time. TCD constructs a temporally blurred slow-path view by smoothing the input waveform and re-encoding it, then contrasts next-token logits from the original and slow-path views. The contrastive signal is applied as a token-level logit update restricted to a small candidate set. A self-normalized stability score sets the blur window and update scale, and a step-wise gate based on uncertainty and audio reliance activates the update only when needed. Experiments on MMAU and AIR-Bench show consistent improvements on strong unified LALMs. We further conduct ablations and an architectural applicability study to analyze the contributions of key components and how TCD behaves across large audio-language model designs.
Anthology ID:
2026.findings-acl.733
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
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Publisher:
Association for Computational Linguistics
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Pages:
14921–14934
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.733/
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Cite (ACL):
Yanda Li, Yuhan Liu, Zirui Song, Yunchao Wei, Martin Tak\'a\v{c}, and Salem Lahlou. 2026. Temporal Contrastive Decoding: A Training-Free Method for Large Audio-Language Models. In Findings of the Association for Computational Linguistics: ACL 2026, pages 14921–14934, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Temporal Contrastive Decoding: A Training-Free Method for Large Audio-Language Models (Li et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.733.pdf
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