nvidia_denoiser / stft_loss.py
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# Adapted from https://github.com/kan-bayashi/ParallelWaveGAN
# Original Copyright 2019 Tomoki Hayashi
# MIT License (https://opensource.org/licenses/MIT)
"""STFT-based Loss modules."""
import torch
import torch.nn.functional as F
from distutils.version import LooseVersion
is_pytorch_17plus = LooseVersion(torch.__version__) >= LooseVersion("1.7")
def stft(x, fft_size, hop_size, win_length, window):
"""Perform STFT and convert to magnitude spectrogram.
Args:
x (Tensor): Input signal tensor (B, T).
fft_size (int): FFT size.
hop_size (int): Hop size.
win_length (int): Window length.
window (str): Window function type.
Returns:
Tensor: Magnitude spectrogram (B, #frames, fft_size // 2 + 1).
"""
if is_pytorch_17plus:
x_stft = torch.stft(
x, fft_size, hop_size, win_length, window, return_complex=False
)
else:
x_stft = torch.stft(x, fft_size, hop_size, win_length, window)
real = x_stft[..., 0]
imag = x_stft[..., 1]
# NOTE(kan-bayashi): clamp is needed to avoid nan or inf
return torch.sqrt(torch.clamp(real**2 + imag**2, min=1e-7)).transpose(2, 1)
class SpectralConvergenceLoss(torch.nn.Module):
"""Spectral convergence loss module."""
def __init__(self):
"""Initilize spectral convergence loss module."""
super(SpectralConvergenceLoss, self).__init__()
def forward(self, x_mag, y_mag):
"""Calculate forward propagation.
Args:
x_mag (Tensor): Magnitude spectrogram of predicted signal (B, #frames, #freq_bins).
y_mag (Tensor): Magnitude spectrogram of groundtruth signal (B, #frames, #freq_bins).
Returns:
Tensor: Spectral convergence loss value.
"""
return torch.norm(y_mag - x_mag, p="fro") / torch.norm(y_mag, p="fro")
class LogSTFTMagnitudeLoss(torch.nn.Module):
"""Log STFT magnitude loss module."""
def __init__(self):
"""Initilize los STFT magnitude loss module."""
super(LogSTFTMagnitudeLoss, self).__init__()
def forward(self, x_mag, y_mag):
"""Calculate forward propagation.
Args:
x_mag (Tensor): Magnitude spectrogram of predicted signal (B, #frames, #freq_bins).
y_mag (Tensor): Magnitude spectrogram of groundtruth signal (B, #frames, #freq_bins).
Returns:
Tensor: Log STFT magnitude loss value.
"""
return F.l1_loss(torch.log(y_mag), torch.log(x_mag))
class STFTLoss(torch.nn.Module):
"""STFT loss module."""
def __init__(
self, fft_size=1024, shift_size=120, win_length=600, window="hann_window",
band="full"
):
"""Initialize STFT loss module."""
super(STFTLoss, self).__init__()
self.fft_size = fft_size
self.shift_size = shift_size
self.win_length = win_length
self.band = band
self.spectral_convergence_loss = SpectralConvergenceLoss()
self.log_stft_magnitude_loss = LogSTFTMagnitudeLoss()
# NOTE(kan-bayashi): Use register_buffer to fix #223
self.register_buffer("window", getattr(torch, window)(win_length))
def forward(self, x, y):
"""Calculate forward propagation.
Args:
x (Tensor): Predicted signal (B, T).
y (Tensor): Groundtruth signal (B, T).
Returns:
Tensor: Spectral convergence loss value.
Tensor: Log STFT magnitude loss value.
"""
x_mag = stft(x, self.fft_size, self.shift_size, self.win_length, self.window)
y_mag = stft(y, self.fft_size, self.shift_size, self.win_length, self.window)
if self.band == "high":
freq_mask_ind = x_mag.shape[1] // 2 # only select high frequency bands
sc_loss = self.spectral_convergence_loss(x_mag[:,freq_mask_ind:,:], y_mag[:,freq_mask_ind:,:])
mag_loss = self.log_stft_magnitude_loss(x_mag[:,freq_mask_ind:,:], y_mag[:,freq_mask_ind:,:])
elif self.band == "full":
sc_loss = self.spectral_convergence_loss(x_mag, y_mag)
mag_loss = self.log_stft_magnitude_loss(x_mag, y_mag)
else:
raise NotImplementedError
return sc_loss, mag_loss
class MultiResolutionSTFTLoss(torch.nn.Module):
"""Multi resolution STFT loss module."""
def __init__(
self, fft_sizes=[1024, 2048, 512], hop_sizes=[120, 240, 50], win_lengths=[600, 1200, 240],
window="hann_window", sc_lambda=0.1, mag_lambda=0.1, band="full"
):
"""Initialize Multi resolution STFT loss module.
Args:
fft_sizes (list): List of FFT sizes.
hop_sizes (list): List of hop sizes.
win_lengths (list): List of window lengths.
window (str): Window function type.
*_lambda (float): a balancing factor across different losses.
band (str): high-band or full-band loss
"""
super(MultiResolutionSTFTLoss, self).__init__()
self.sc_lambda = sc_lambda
self.mag_lambda = mag_lambda
assert len(fft_sizes) == len(hop_sizes) == len(win_lengths)
self.stft_losses = torch.nn.ModuleList()
for fs, ss, wl in zip(fft_sizes, hop_sizes, win_lengths):
self.stft_losses += [STFTLoss(fs, ss, wl, window, band)]
def forward(self, x, y):
"""Calculate forward propagation.
Args:
x (Tensor): Predicted signal (B, T) or (B, #subband, T).
y (Tensor): Groundtruth signal (B, T) or (B, #subband, T).
Returns:
Tensor: Multi resolution spectral convergence loss value.
Tensor: Multi resolution log STFT magnitude loss value.
"""
if len(x.shape) == 3:
x = x.view(-1, x.size(2)) # (B, C, T) -> (B x C, T)
y = y.view(-1, y.size(2)) # (B, C, T) -> (B x C, T)
sc_loss = 0.0
mag_loss = 0.0
for f in self.stft_losses:
sc_l, mag_l = f(x, y)
sc_loss += sc_l
mag_loss += mag_l
sc_loss *= self.sc_lambda
sc_loss /= len(self.stft_losses)
mag_loss *= self.mag_lambda
mag_loss /= len(self.stft_losses)
return sc_loss, mag_loss