# Copyright (c) 2020 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 math
import paddle
from paddle import nn
from paddle.fluid.layers import sequence_mask
from paddle.nn import functional as F
from scipy import signal
# Loss for Tacotron2
def attention_guide(dec_lens, enc_lens, N, T, g, dtype=None):
"""Build that W matrix. shape(B, T_dec, T_enc)
W[i, n, t] = 1 - exp(-(n/dec_lens[i] - t/enc_lens[i])**2 / (2g**2))
See also:
Tachibana, Hideyuki, Katsuya Uenoyama, and Shunsuke Aihara. 2017. “Efficiently Trainable Text-to-Speech System Based on Deep Convolutional Networks with Guided Attention.” ArXiv:1710.08969 [Cs, Eess], October. http://arxiv.org/abs/1710.08969.
"""
dtype = dtype or paddle.get_default_dtype()
dec_pos = paddle.arange(0, N).astype(dtype) / dec_lens.unsqueeze(
-1) # n/N # shape(B, T_dec)
enc_pos = paddle.arange(0, T).astype(dtype) / enc_lens.unsqueeze(
-1) # t/T # shape(B, T_enc)
W = 1 - paddle.exp(-(dec_pos.unsqueeze(-1) - enc_pos.unsqueeze(1))**2 /
(2 * g**2))
dec_mask = sequence_mask(dec_lens, maxlen=N)
enc_mask = sequence_mask(enc_lens, maxlen=T)
mask = dec_mask.unsqueeze(-1) * enc_mask.unsqueeze(1)
mask = paddle.cast(mask, W.dtype)
W *= mask
return W
def guided_attention_loss(attention_weight, dec_lens, enc_lens, g):
"""Guided attention loss, masked to excluded padding parts."""
_, N, T = attention_weight.shape
W = attention_guide(dec_lens, enc_lens, N, T, g, attention_weight.dtype)
total_tokens = (dec_lens * enc_lens).astype(W.dtype)
loss = paddle.mean(paddle.sum(W * attention_weight, [1, 2]) / total_tokens)
return loss
# Losses for GAN Vocoder
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
class GeneratorAdversarialLoss(nn.Layer):
"""Generator adversarial loss module."""
def __init__(
self,
average_by_discriminators=True,
loss_type="mse", ):
"""Initialize GeneratorAversarialLoss module."""
super().__init__()
self.average_by_discriminators = average_by_discriminators
assert loss_type in ["mse", "hinge"], f"{loss_type} is not supported."
if loss_type == "mse":
self.criterion = self._mse_loss
else:
self.criterion = self._hinge_loss
def forward(self, outputs):
"""Calcualate generator adversarial loss.
Parameters
----------
outputs: Tensor or List
Discriminator outputs or list of discriminator outputs.
Returns
----------
Tensor
Generator adversarial loss value.
"""
if isinstance(outputs, (tuple, list)):
adv_loss = 0.0
for i, outputs_ in enumerate(outputs):
if isinstance(outputs_, (tuple, list)):
# case including feature maps
outputs_ = outputs_[-1]
adv_loss += self.criterion(outputs_)
if self.average_by_discriminators:
adv_loss /= i + 1
else:
adv_loss = self.criterion(outputs)
return adv_loss
def _mse_loss(self, x):
return F.mse_loss(x, paddle.ones_like(x))
def _hinge_loss(self, x):
return -x.mean()
class DiscriminatorAdversarialLoss(nn.Layer):
"""Discriminator adversarial loss module."""
def __init__(
self,
average_by_discriminators=True,
loss_type="mse", ):
"""Initialize DiscriminatorAversarialLoss module."""
super().__init__()
self.average_by_discriminators = average_by_discriminators
assert loss_type in ["mse"], f"{loss_type} is not supported."
if loss_type == "mse":
self.fake_criterion = self._mse_fake_loss
self.real_criterion = self._mse_real_loss
def forward(self, outputs_hat, outputs):
"""Calcualate discriminator adversarial loss.
Parameters
----------
outputs_hat : Tensor or list
Discriminator outputs or list of
discriminator outputs calculated from generator outputs.
outputs : Tensor or list
Discriminator outputs or list of
discriminator outputs calculated from groundtruth.
Returns
----------
Tensor
Discriminator real loss value.
Tensor
Discriminator fake loss value.
"""
if isinstance(outputs, (tuple, list)):
real_loss = 0.0
fake_loss = 0.0
for i, (outputs_hat_,
outputs_) in enumerate(zip(outputs_hat, outputs)):
if isinstance(outputs_hat_, (tuple, list)):
# case including feature maps
outputs_hat_ = outputs_hat_[-1]
outputs_ = outputs_[-1]
real_loss += self.real_criterion(outputs_)
fake_loss += self.fake_criterion(outputs_hat_)
if self.average_by_discriminators:
fake_loss /= i + 1
real_loss /= i + 1
else:
real_loss = self.real_criterion(outputs)
fake_loss = self.fake_criterion(outputs_hat)
return real_loss, fake_loss
def _mse_real_loss(self, x):
return F.mse_loss(x, paddle.ones_like(x))
def _mse_fake_loss(self, x):
return F.mse_loss(x, paddle.zeros_like(x))
# Losses for SpeedySpeech
# Structural Similarity Index Measure (SSIM)
def gaussian(window_size, sigma):
gauss = paddle.to_tensor([
math.exp(-(x - window_size // 2)**2 / float(2 * sigma**2))
for x in range(window_size)
])
return gauss / gauss.sum()
def create_window(window_size, channel):
_1D_window = gaussian(window_size, 1.5).unsqueeze(1)
_2D_window = paddle.matmul(_1D_window, paddle.transpose(
_1D_window, [1, 0])).unsqueeze([0, 1])
window = paddle.expand(_2D_window, [channel, 1, window_size, window_size])
return window
def _ssim(img1, img2, window, window_size, channel, size_average=True):
mu1 = F.conv2d(img1, window, padding=window_size // 2, groups=channel)
mu2 = F.conv2d(img2, window, padding=window_size // 2, groups=channel)
mu1_sq = mu1.pow(2)
mu2_sq = mu2.pow(2)
mu1_mu2 = mu1 * mu2
sigma1_sq = F.conv2d(
img1 * img1, window, padding=window_size // 2, groups=channel) - mu1_sq
sigma2_sq = F.conv2d(
img2 * img2, window, padding=window_size // 2, groups=channel) - mu2_sq
sigma12 = F.conv2d(
img1 * img2, window, padding=window_size // 2, groups=channel) - mu1_mu2
C1 = 0.01**2
C2 = 0.03**2
ssim_map = ((2 * mu1_mu2 + C1) * (2 * sigma12 + C2)) \
/ ((mu1_sq + mu2_sq + C1) * (sigma1_sq + sigma2_sq + C2))
if size_average:
return ssim_map.mean()
else:
return ssim_map.mean(1).mean(1).mean(1)
def ssim(img1, img2, window_size=11, size_average=True):
(_, channel, _, _) = img1.shape
window = create_window(window_size, channel)
return _ssim(img1, img2, window, window_size, channel, size_average)
def weighted_mean(input, weight):
"""Weighted mean. It can also be used as masked mean.
Parameters
-----------
input : Tensor
The input tensor.
weight : Tensor
The weight tensor with broadcastable shape with the input.
Returns
----------
Tensor [shape=(1,)]
Weighted mean tensor with the same dtype as input.
"""
weight = paddle.cast(weight, input.dtype)
broadcast_ratio = input.size / weight.size
return paddle.sum(input * weight) / (paddle.sum(weight) * broadcast_ratio)
def masked_l1_loss(prediction, target, mask):
"""Compute maksed L1 loss.
Parameters
----------
prediction : Tensor
The prediction.
target : Tensor
The target. The shape should be broadcastable to ``prediction``.
mask : Tensor
The mask. The shape should be broadcatable to the broadcasted shape of
``prediction`` and ``target``.
Returns
-------
Tensor [shape=(1,)]
The masked L1 loss.
"""
abs_error = F.l1_loss(prediction, target, reduction='none')
loss = weighted_mean(abs_error, mask)
return loss