OmniRetriever: Any-to-Any Audio-Video-Text Retrieval via Fusion-as-Teacher Distillation

Yunze Liu, Chi-Hao Wu, Enmin Zhou, Junxiao Shen


Abstract
Unified multimodal embedding spaces have become the standard interface for cross-modal retrieval and multimodal RAG, and recent audio-video-text (AVT) encoders extend this setting to three modalities. Such encoders can produce a joint (T, V, A) embedding whenever all three modalities are available, but standard pairwise InfoNCE objectives leave this signal unused during training. We close this gap with fusion-as-teacher distillation, which treats a stop-gradient copy of the fused embedding as a teacher signal for the single-modal embedding, paired with a Tuple-InfoNCE term that supervises the fused embedding directly. We instantiate this objective as OmniRetriever-7B. Across six zero-shot retrieval benchmarks, OmniRetriever-7B reaches R@1 of 19.14 on Clotho text-to-audio and 47.60 on MSR-VTT text-to-video. To stress-test joint representations, we further release OmniRetriever-Bench, a 12-direction AVT retrieval benchmark totaling 3,782 triples; on it OmniRetriever-7B attains AVG-all 34.84, improving over the best prior open-source AVT method by +8.03. Model weights, datasets, and code are released.
Anthology ID:
2026.emnlp-main.541
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:
12455–12472
Language:
URL:
https://aclanthology.org/2026.emnlp-main.541/
DOI:
Bibkey:
Cite (ACL):
Yunze Liu, Chi-Hao Wu, Enmin Zhou, and Junxiao Shen. 2026. OmniRetriever: Any-to-Any Audio-Video-Text Retrieval via Fusion-as-Teacher Distillation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 12455–12472, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
OmniRetriever: Any-to-Any Audio-Video-Text Retrieval via Fusion-as-Teacher Distillation (Liu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.541.pdf