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RESEARCH PAPER / 2023-06-13

StyleTTS 2: Towards Human-Level Text-to-Speech through Style Diffusion and Adversarial Training with Large Speech Language Models

Yinghao Aaron Li, Cong Han, Vinay S. Raghavan ...Full author list in the original paper.

Columbia University · arxiv

Affiliations: Columbia University

Abstract

In this paper, we present StyleTTS 2, a text-to-speech (TTS) model that leverages style diffusion and adversarial training with large speech language models (SLMs) to achieve human-level TTS synthesis. StyleTTS 2 differs from its predecessor by modeling styles as a latent random variable through diffusion models to generate the most suitable style for the text without requiring reference speech, achieving efficient latent diffusion while benefiting from the diverse speech synthesis offered by diffusion models. Furthermore, we employ large pre-trained SLMs, such as WavLM, as discriminators with our novel differentiable duration modeling for end-to-end training, resulting in improved speech naturalness. StyleTTS 2 surpasses human recordings on the single-speaker LJSpeech dataset and matches it on the multispeaker VCTK dataset as judged by native English speakers. Moreover, when trained on the LibriTTS dataset, our model outperforms previous publicly available models for zero-shot speaker adaptation. This work achieves the first human-level TTS on both single and multispeaker datasets, showcasing the potential of style diffusion and adversarial training with large SLMs. The audio demos and source code are available at https://styletts2.github.io/.

The following analysis is generated by AI and may contain errors. It is separate from the authors’ abstract and is not peer review.

Research summary

StyleTTS 2 represents a substantial advancement in text-to-speech synthesis, achieving human-level quality through innovative methodologies that leverage style diffusion and large speech language models. The comprehensive evaluation and results highlight its potential impact on the field, while also addressing ethical implications associated with its deployment.

Methodology

The methodology of StyleTTS 2 is innovative, particularly in its use of style diffusion and adversarial training with large speech language models (SLMs). The paper presents a well-structured approach that models styles as latent random variables, allowing for efficient synthesis of diverse speech without reference audio. The integration of differentiable duration modeling and end-to-end training is a significant advancement, enhancing the naturalness of generated speech. The use of large pre-trained SLMs as discriminators is a novel contribution that effectively leverages existing models to improve the quality of TTS synthesis.

Results & evaluation

The experimental evaluation is robust, utilizing multiple datasets (LJSpeech, VCTK, and LibriTTS) and employing both subjective (CMOS, MOS) and objective metrics to assess performance. The results demonstrate that StyleTTS 2 surpasses human recordings on LJSpeech and matches them on VCTK, which is a significant achievement. The zero-shot speaker adaptation capabilities are particularly noteworthy, showcasing the model's efficiency in utilizing limited training data. The ablation studies further validate the importance of various components in the model.

Reproducibility

The paper provides sufficient details regarding the training process, datasets, and evaluation metrics, which supports reproducibility. However, the absence of a specific venue and citation count may hinder broader dissemination and validation of the results by the community.

Limitations

The paper acknowledges limitations in handling large-scale datasets like LibriTTS and the potential for misuse in zero-shot speaker adaptation. The subjective nature of human evaluations may also introduce variability in results, particularly in context-dependent scenarios. Additionally, the model's performance on diverse accents and speaking styles could be further explored.

Broader impact

The advancements in TTS synthesis have significant implications for applications in virtual assistants, audiobooks, and other domains requiring natural and expressive speech. However, the potential for misuse in voice impersonation and misinformation is a critical concern that necessitates ethical considerations and guidelines for usage. StyleTTS 2 represents a substantial advancement in text-to-speech synthesis, achieving human-level quality through innovative methodologies that leverage style diffusion and large speech language models. The comprehensive evaluation and results highlight its potential impact on the field, while also addressing ethical implications associated with its deployment.

Curator note

Li et al., Columbia; style diffusion + adversarial training; first open-source TTS to rival commercial systems

Other indexed descriptions from the archive

StyleTTS 2: Towards Human-Level Text-to-Speech through Style Diffusion and Adversarial Training

Yinghao Aaron Li, Cong Han, Vinay S. Raghavan ...

Abstract

In this paper, we present StyleTTS 2, a text-to-speech (TTS) model that leverages style diffusion and adversarial training with large speech language models (SLMs) to achieve human-level TTS synthesis. StyleTTS 2 differs from its predecessor by modeling styles as a latent random variable through diffusion models to generate the most suitable style for the text without requiring reference speech, achieving efficient latent diffusion while benefiting from the diverse speech synthesis offered by diffusion models. Furthermore, we employ large pre-trained SLMs, such as WavLM, as discriminators with our novel differentiable duration modeling for end-to-end training, resulting in improved speech naturalness. StyleTTS 2 surpasses human recordings on the single-speaker LJSpeech dataset and matches it on the multispeaker VCTK dataset as judged by native English speakers. Moreover, when trained on the LibriTTS dataset, our model outperforms previous publicly available models for zero-shot speaker adaptation. This work achieves the first human-level TTS on both single and multispeaker datasets, showcasing the potential of style diffusion and adversarial training with large SLMs. The audio demos and source code are available at https://styletts2.github.io/.

AI research summary

StyleTTS 2 represents a substantial advancement in text-to-speech synthesis, achieving human-level quality through innovative methodologies that leverage style diffusion and large speech language models. The comprehensive evaluation and results highlight its potential impact on the field, while also addressing ethical implications associated with its deployment.

AI methodology analysis

The methodology of StyleTTS 2 is innovative, particularly in its use of style diffusion and adversarial training with large speech language models (SLMs). The paper presents a well-structured approach that models styles as latent random variables, allowing for efficient synthesis of diverse speech without reference audio. The integration of differentiable duration modeling and end-to-end training is a significant advancement, enhancing the naturalness of generated speech. The use of large pre-trained SLMs as discriminators is a novel contribution that effectively leverages existing models to improve the quality of TTS synthesis.

AI results analysis

The experimental evaluation is robust, utilizing multiple datasets (LJSpeech, VCTK, and LibriTTS) and employing both subjective (CMOS, MOS) and objective metrics to assess performance. The results demonstrate that StyleTTS 2 surpasses human recordings on LJSpeech and matches them on VCTK, which is a significant achievement. The zero-shot speaker adaptation capabilities are particularly noteworthy, showcasing the model's efficiency in utilizing limited training data. The ablation studies further validate the importance of various components in the model.

AI reproducibility analysis

The paper provides sufficient details regarding the training process, datasets, and evaluation metrics, which supports reproducibility. However, the absence of a specific venue and citation count may hinder broader dissemination and validation of the results by the community.

AI limitations analysis

The paper acknowledges limitations in handling large-scale datasets like LibriTTS and the potential for misuse in zero-shot speaker adaptation. The subjective nature of human evaluations may also introduce variability in results, particularly in context-dependent scenarios. Additionally, the model's performance on diverse accents and speaking styles could be further explored.

AI broader impact analysis

The advancements in TTS synthesis have significant implications for applications in virtual assistants, audiobooks, and other domains requiring natural and expressive speech. However, the potential for misuse in voice impersonation and misinformation is a critical concern that necessitates ethical considerations and guidelines for usage. StyleTTS 2 represents a substantial advancement in text-to-speech synthesis, achieving human-level quality through innovative methodologies that leverage style diffusion and large speech language models. The comprehensive evaluation and results highlight its potential impact on the field, while also addressing ethical implications associated with its deployment.

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