TC-BiMamba: Efficient Dynamic-Chunk Bidirectional Mamba for Unified Streaming and Offline ASR

Jing Peng, Qingshun She, Yangui Fang, Yu Xi, Shuai Wang, Kai Yu


Abstract
Unified streaming and offline ASR aims to deliver full-context accuracy and low-latency incremental decoding with a single model. Transformer/Conformer systems are effective, but long-form streaming inference still suffers from growing attention masks, historical caches, and memory states. Latency-Controlled BiMamba (LC-BiMamba) offers attention-free bidirectional modeling, yet its backward branch is confined to fixed chunks, tying the model to one latency. Extending it to dynamic chunk training expands mini-batches and slows training. We propose TC-BiMamba, whose Trans-Chunk formulation casts local-future backward modeling as sequence-level dynamic-chunk training over complete sequences. TC-BiMamba supports multiple chunk-wise latency settings, keeps the encoder/CTC path memory-stable on long-form inputs, and improves training scalability. On AISHELL-1, AISHELL-2, and LibriSpeech, it outperforms U2++ and remains competitive with externally reported LC-BiMamba results using fewer parameters, while achieving 1.3 times training speedup and 50% GPU memory reduction.
Anthology ID:
2026.findings-emnlp.330
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:
6976–6985
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.330/
DOI:
Bibkey:
Cite (ACL):
Jing Peng, Qingshun She, Yangui Fang, Yu Xi, Shuai Wang, and Kai Yu. 2026. TC-BiMamba: Efficient Dynamic-Chunk Bidirectional Mamba for Unified Streaming and Offline ASR. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 6976–6985, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
TC-BiMamba: Efficient Dynamic-Chunk Bidirectional Mamba for Unified Streaming and Offline ASR (Peng et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.330.pdf