UnivNet

UnivNet: A Neural Vocoder with Multi-Resolution Spectrogram Discriminators for High-Fidelity Waveform Generation

This is an unofficial PyTorch implementation of Jang et al. (Kakao), UnivNet.

Audio samples are uploaded!

Notes

Both UnivNet-c16 and c32 results and the pre-trained weights have been uploaded.

For both models, our implementation matches the objective scores (PESQ and RMSE) of the original paper.

Key Features

• According to the authors of the paper, UnivNet obtained the best objective results among the recent GAN-based neural vocoders (including HiFi-GAN) as well as outperforming HiFi-GAN in a subjective evaluation. Also its inference speed is 1.5 times faster than HiFi-GAN.

• This repository uses the same mel-spectrogram function as the Official HiFi-GAN, which is compatible with NVIDIA/tacotron2.

• Our default mel calculation hyperparameters are as below, following the original paper.

  audio:
    n_mel_channels: 100
    filter_length: 1024
    hop_length: 256 # WARNING: this can't be changed.
    win_length: 1024
    sampling_rate: 24000
    mel_fmin: 0.0
    mel_fmax: 12000.0

  You can modify the hyperparameters to be compatible with your acoustic model.

Prerequisites

The implementation needs following dependencies.

0. Python 3.6
1. PyTorch 1.6.0
2. NumPy 1.17.4 and SciPy 1.5.4
3. Install other dependencies in requirements.txt.

   pip install -r requirements.txt

Datasets

Preparing Data

• Download the training dataset. This can be any wav file with sampling rate 24,000Hz. The original paper used LibriTTS.
  • LibriTTS train-clean-360 split tar.gz link
  • Unzip and place its contents under datasets/LibriTTS/train-clean-360.
• If you want to use wav files with a different sampling rate, please edit the configuration file (see below).

Note: The mel-spectrograms calculated from audio file will be saved as **.mel at first, and then loaded from disk afterwards.

Preparing Metadata

Following the format from NVIDIA/tacotron2, the metadata should be formatted as:

path_to_wav|transcript|speaker_id
path_to_wav|transcript|speaker_id
...

Train/validation metadata for LibriTTS train-clean-360 split and are already prepared in datasets/metadata. 5% of the train-clean-360 utterances were randomly sampled for validation.

Since this model is a vocoder, the transcripts are NOT used during training.

Train

Preparing Configuration Files

• Run cp config/default_c32.yaml config/config.yaml and then edit config.yaml

• Write down the root path of train/validation in the data section. The data loader parses list of files within the path recursively.

  data:
    train_dir: 'datasets/'	# root path of train data (either relative/absoulte path is ok)
    train_meta: 'metadata/libritts_train_clean_360_train.txt'	# relative path of metadata file from train_dir
    val_dir: 'datasets/'		# root path of validation data
    val_meta: 'metadata/libritts_train_clean_360_val.txt'		# relative path of metadata file from val_dir

  We provide the default metadata for LibriTTS train-clean-360 split.

• Modify channel_size in gen to switch between UnivNet-c16 and c32.

  gen:
    noise_dim: 64
    channel_size: 32 # 32 or 16
    dilations: [1, 3, 9, 27]
    strides: [8, 8, 4]
    lReLU_slope: 0.2

Training

python trainer.py -c CONFIG_YAML_FILE -n NAME_OF_THE_RUN

Tensorboard

tensorboard --logdir logs/

If you are running tensorboard on a remote machine, you can open the tensorboard page by adding --bind_all option.

Inference

python inference.py -p CHECKPOINT_PATH -i INPUT_MEL_PATH -o OUTPUT_WAV_PATH

Pre-trained Model

You can download the pre-trained models from the Google Drive link below. The models were trained on LibriTTS train-clean-360 split.

• UnivNet-c16: Google Drive
• UnivNet-c32: Google Drive

Results

See audio samples at https://mindslab-ai.github.io/univnet/

We evaluated our model with validation set.

Model	PESQ(↑)	RMSE(↓)	Model Size
HiFi-GAN v1	3.54	0.423	14.01M
Official UnivNet-c16	3.59	0.337	4.00M
Our UnivNet-c16	3.60	0.317	4.00M
Official UnivNet-c32	3.70	0.316	14.86M
Our UnivNet-c32	3.68	0.304	14.87M

The loss graphs of UnivNet are listed below.

The orange and blue graphs indicate c16 and c32, respectively.

Implementation Authors

Implementation authors are:

• Kang-wook Kim @ MINDsLab Inc. (full324@snu.ac.kr, kwkim@mindslab.ai)
• Wonbin Jung @ MINDsLab Inc. (santabin@kaist.ac.kr, wbjung@mindslab.ai)

Contributors are:

• Kuan Chen

Special thanks to

• Seungu Han @ MINDsLab Inc.
• Junhyeok Lee @ MINDsLab Inc.
• Sang Hoon Woo @ MINDsLab Inc.

License

This code is licensed under BSD 3-Clause License.

We referred following codes and repositories.

• The overall structure of the repository is based on https://github.com/seungwonpark/melgan.
• datasets/dataloader.py from https://github.com/NVIDIA/waveglow (BSD 3-Clause License)
• model/mpd.py from https://github.com/jik876/hifi-gan (MIT License)
• model/lvcnet.py from https://github.com/zceng/LVCNet (Apache License 2.0)
• utils/stft_loss.py # Copyright 2019 Tomoki Hayashi # MIT License (https://opensource.org/licenses/MIT)

References

Papers

• Jang et al., UnivNet: A Neural Vocoder with Multi-Resolution Spectrogram Discriminators for High-Fidelity Waveform Generation
• Zeng et al., LVCNet: Efficient Condition-Dependent Modeling Network for Waveform Generation
• Kong et al., HiFi-GAN: Generative Adversarial Networks for Efficient and High Fidelity Speech Synthesis

Datasets

• LibriTTS