WaveFM: A High-Fidelity and Efficient Vocoder Based on Flow Matching

Tianze Luo, Xingchen Miao, Wenbo Duan


Abstract
Flow matching offers a robust and stable approach to training diffusion models. However, directly applying flow matching to neural vocoders can result in subpar audio quality. In this work, we present WaveFM, a reparameterized flow matching model for mel-spectrogram conditioned speech synthesis, designed to enhance both sample quality and generation speed for diffusion vocoders. Since mel-spectrograms represent the energy distribution of waveforms, WaveFM adopts a mel-conditioned prior distribution instead of a standard Gaussian prior to minimize unnecessary transportation costs during synthesis. Moreover, while most diffusion vocoders rely on a single loss function, we argue that incorporating auxiliary losses, including a refined multi-resolution STFT loss, can further improve audio quality. To speed up inference without degrading sample quality significantly, we introduce a tailored consistency distillation method for WaveFM. Experiment results demonstrate that our model achieves superior performance in both quality and efficiency compared to previous diffusion vocoders, while enabling waveform generation in a single inference step.
Anthology ID:
2025.naacl-long.110
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2187–2198
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.110/
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Bibkey:
Cite (ACL):
Tianze Luo, Xingchen Miao, and Wenbo Duan. 2025. WaveFM: A High-Fidelity and Efficient Vocoder Based on Flow Matching. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers), pages 2187–2198, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
WaveFM: A High-Fidelity and Efficient Vocoder Based on Flow Matching (Luo et al., NAACL 2025)
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https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.110.pdf