Model Overview

MelGAN is a generative adversarial network (GAN) model that generates audio from mel spectrograms. This checkpoint implements the full-band MelGAN as described in the Multi-band MelGAN paper [1].

Model Architecture

The MelGAN generator uses transposed convolutions to upscale by the mel spectrogram to audio.

Training

This model is trained on LJSpeech sampled at 22050Hz, and has been tested on generating female English voices with an American accent. All NeMo models are trained in accordance with the model yaml. In particular, this model was trained on 8 16GB V100 gpus for 3000 epochs with a batch size of 64.

Performance

No performance information available at this time.

How to Use this Model

This model can be automatically loaded from NGC. NOTE: In order to generate audio, you also need a spectrogram generator from NeMo. This example uses the FastPitch model.

# Load spectrogram generator
from nemo.collections.tts.models import FastPitchModel
spec_generator = FastPitchModel.from_pretrained("tts_en_fastpitch")

# Load Melgan
from nemo.collections.tts.models import MelGanModel
model = MelGanModel.from_pretrained(model_name="tts_melgan")

# Generate audio
import soundfile as sf
parsed = spec_generator.parse("You can type your sentence here to get nemo to produce speech.")
spectrogram = spec_generator.generate_spectrogram(tokens=parsed)
audio = model.convert_spectrogram_to_audio(spec=spectrogram)

# Save the audio to disk in a file called speech.wav
sf.write("speech.wav", audio.to('cpu').numpy(), 22050)

Input

This model accepts batches of mel spectrograms.

Output

This model outputs audio at 22050Hz.

Limitations

There are no known limitations at this time.

Versions

1.0.0 (current): An updated version of melgan that standardizes mel spectrogram generation across NeMo models.

1.0.0rc1: The original version that was released with NeMo 1.0.0.rc1

References

MelGAN paper: https://arxiv.org/abs/1910.06711

Multi-band MelGAN paper: https://arxiv.org/abs/2005.05106

Licence

License to use this model is covered by the NGC TERMS OF USE unless another License/Terms Of Use/EULA is clearly specified. By downloading the public and release version of the model, you accept the terms and conditions of the NGC TERMS OF USE.