OZSpeech: One-step Zero-shot Speech Synthesis with Learned-Prior-Conditioned Flow Matching
Nghia Huynh Nguyen Hieu, Ngoc Son Nguyen, Huynh Nguyen Dang, Thieu Vo, Truong-Son Hy, Van Nguyen
Abstract
Text-to-speech (TTS) systems have seen significant advancements in recent years, driven by improvements in deep learning and neural network architectures. Viewing the output speech as a data distribution, previous approaches often employ traditional speech representations, such as waveforms or spectrograms, within the Flow Matching framework. However, these methods have limitations, including overlooking various speech attributes and incurring high computational costs due to additional constraints introduced during training. To address these challenges, we introduce OZSpeech, the first TTS method to explore optimal transport conditional flow matching with one-step sampling and a learned prior as the condition, effectively disregarding preceding states and reducing the number of sampling steps. Our approach operates on disentangled, factorized components of speech in token format, enabling accurate modeling of each speech attribute, which enhances the TTS system’s ability to precisely clone the prompt speech. Experimental results show that our method achieves promising performance over existing methods in content accuracy, naturalness, prosody generation, and speaker style preservation. Audio samples are available at our demo page https://ozspeech.github.io/OZSpeech_Web/.- Anthology ID:
- 2025.acl-long.1043
- Volume:
- Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
- Month:
- July
- Year:
- 2025
- Address:
- Vienna, Austria
- Editors:
- Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
- Venue:
- ACL
- SIG:
- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 21500–21517
- Language:
- URL:
- https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.1043/
- DOI:
- Cite (ACL):
- Nghia Huynh Nguyen Hieu, Ngoc Son Nguyen, Huynh Nguyen Dang, Thieu Vo, Truong-Son Hy, and Van Nguyen. 2025. OZSpeech: One-step Zero-shot Speech Synthesis with Learned-Prior-Conditioned Flow Matching. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 21500–21517, Vienna, Austria. Association for Computational Linguistics.
- Cite (Informal):
- OZSpeech: One-step Zero-shot Speech Synthesis with Learned-Prior-Conditioned Flow Matching (Hieu et al., ACL 2025)
- PDF:
- https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.1043.pdf