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RESEARCH PAPER / 2016-12-22

SampleRNN: An Unconditional End-to-End Neural Audio Generation Model

★ Soroush Mehri , ★ Kundan Kumar , Ishaan Gulrajani, ★ Rithesh Kumar , ★ Yoshua Bengio ...Full author list in the original paper.

University of Montreal · arxiv

Affiliations: University of Montreal

Abstract

In this paper we propose a novel model for unconditional audio generation based on generating one audio sample at a time. We show that our model, which profits from combining memory-less modules, namely autoregressive multilayer perceptrons, and stateful recurrent neural networks in a hierarchical structure is able to capture underlying sources of variations in the temporal sequences over very long time spans, on three datasets of different nature. Human evaluation on the generated samples indicate that our model is preferred over competing models. We also show how each component of the model contributes to the exhibited performance.

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

The main contribution of this paper is the introduction of SampleRNN, a novel end-to-end neural audio generation model that effectively captures long-term dependencies in audio signals through a hierarchical structure of autoregressive and recurrent components. This work represents a substantial advancement in the field of audio generation, providing a framework that can be adapted for various applications while achieving high-quality results as validated by human preference evaluations.

Methodology

The methodology presented in SampleRNN is innovative, leveraging a hierarchical structure of autoregressive multilayer perceptrons and stateful recurrent neural networks to model audio generation at different temporal resolutions. This approach allows the model to efficiently capture long-term dependencies in audio signals while generating samples at a high temporal resolution. The use of discrete output distributions and the combination of memory-less and stateful components is particularly notable, as it addresses challenges in traditional audio generation methods that rely on handcrafted features.

Results & evaluation

The experimental setup is robust, utilizing three diverse datasets for evaluation, including speech, vocal sounds, and music. The paper reports both objective metrics (negative log-likelihood) and subjective evaluations through human preference tests, demonstrating the model's superiority over competing architectures like WaveNet. The human evaluation results are particularly strong, indicating a clear preference for the samples generated by SampleRNN, which adds credibility to the findings.

Reproducibility

The paper provides a detailed account of the architecture, training procedures, and hyperparameter settings, which enhances reproducibility. The availability of code and sample audio through the provided URLs further supports efforts to replicate the results. However, the paper mentions challenges in replicating the WaveNet architecture due to missing details, which could hinder full reproducibility of comparative results.

Limitations

One limitation noted is the reliance on specific datasets, which may not generalize across all audio generation tasks. Additionally, while the model shows promise in generating coherent audio, the complexity of the architecture may lead to challenges in training and tuning for other types of audio data. The paper does not extensively discuss potential biases in the datasets used for training and evaluation.

Broader impact

The implications of this research are significant for various applications in audio synthesis, including music generation, speech synthesis, and sound design. The ability to generate high-quality audio samples without relying on handcrafted features opens avenues for more flexible and adaptive audio generation systems. The hierarchical modeling approach could also inspire future research in other sequential data domains, such as video or text generation. The main contribution of this paper is the introduction of SampleRNN, a novel end-to-end neural audio generation model that effectively captures long-term dependencies in audio signals through a hierarchical structure of autoregressive and recurrent components. This work represents a substantial advancement in the field of audio generation, providing a framework that can be adapted for various applications while achieving high-quality results as validated by human preference evaluations.

Curator note

Mehri et al.; hierarchical RNN for raw audio; showed unconditional audio generation is feasible

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