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PaddleSpeech/parakeet/modules/stft_loss.py

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# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import paddle
from paddle import nn
from paddle.nn import functional as F
from scipy import signal
def stft(x,
fft_size,
hop_length=None,
win_length=None,
window='hann',
center=True,
pad_mode='reflect'):
"""Perform STFT and convert to magnitude spectrogram.
Parameters
----------
x : Tensor
Input signal tensor (B, T).
fft_size : int
FFT size.
hop_size : int
Hop size.
win_length : int
window : str, optional
window : str
Name of window function, see `scipy.signal.get_window` for more
details. Defaults to "hann".
center : bool, optional
center (bool, optional): Whether to pad `x` to make that the
:math:`t \times hop\_length` at the center of :math:`t`-th frame. Default: `True`.
pad_mode : str, optional
Choose padding pattern when `center` is `True`.
Returns
----------
Tensor:
Magnitude spectrogram (B, #frames, fft_size // 2 + 1).
"""
# calculate window
window = signal.get_window(window, win_length, fftbins=True)
window = paddle.to_tensor(window)
x_stft = paddle.signal.stft(
x,
fft_size,
hop_length,
win_length,
window=window,
center=center,
pad_mode=pad_mode)
real = x_stft.real()
imag = x_stft.imag()
return paddle.sqrt(paddle.clip(real**2 + imag**2, min=1e-7)).transpose(
[0, 2, 1])
class SpectralConvergenceLoss(nn.Layer):
"""Spectral convergence loss module."""
def __init__(self):
"""Initilize spectral convergence loss module."""
super().__init__()
def forward(self, x_mag, y_mag):
"""Calculate forward propagation.
Parameters
----------
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 paddle.norm(
y_mag - x_mag, p="fro") / paddle.clip(
paddle.norm(y_mag, p="fro"), min=1e-10)
class LogSTFTMagnitudeLoss(nn.Layer):
"""Log STFT magnitude loss module."""
def __init__(self, epsilon=1e-7):
"""Initilize los STFT magnitude loss module."""
super().__init__()
self.epsilon = epsilon
def forward(self, x_mag, y_mag):
"""Calculate forward propagation.
Parameters
----------
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(
paddle.log(paddle.clip(y_mag, min=self.epsilon)),
paddle.log(paddle.clip(x_mag, min=self.epsilon)))
class STFTLoss(nn.Layer):
"""STFT loss module."""
def __init__(self,
fft_size=1024,
shift_size=120,
win_length=600,
window="hann"):
"""Initialize STFT loss module."""
super().__init__()
self.fft_size = fft_size
self.shift_size = shift_size
self.win_length = win_length
self.window = window
self.spectral_convergence_loss = SpectralConvergenceLoss()
self.log_stft_magnitude_loss = LogSTFTMagnitudeLoss()
def forward(self, x, y):
"""Calculate forward propagation.
Parameters
----------
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)
sc_loss = self.spectral_convergence_loss(x_mag, y_mag)
mag_loss = self.log_stft_magnitude_loss(x_mag, y_mag)
return sc_loss, mag_loss
class MultiResolutionSTFTLoss(nn.Layer):
"""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", ):
"""Initialize Multi resolution STFT loss module.
Parameters
----------
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.
"""
super().__init__()
assert len(fft_sizes) == len(hop_sizes) == len(win_lengths)
self.stft_losses = nn.LayerList()
for fs, ss, wl in zip(fft_sizes, hop_sizes, win_lengths):
self.stft_losses.append(STFTLoss(fs, ss, wl, window))
def forward(self, x, y):
"""Calculate forward propagation.
Parameters
----------
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:
# (B, C, T) -> (B x C, T)
x = x.reshape([-1, x.shape[2]])
# (B, C, T) -> (B x C, T)
y = y.reshape([-1, y.shape[2]])
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 /= len(self.stft_losses)
mag_loss /= len(self.stft_losses)
return sc_loss, mag_loss