IMS-Toucan / Layers /DurationPredictor.py
Florian Lux
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# Copyright 2019 Tomoki Hayashi
# MIT License (https://opensource.org/licenses/MIT)
# Adapted by Florian Lux 2021
import torch
from Layers.LayerNorm import LayerNorm
class DurationPredictor(torch.nn.Module):
"""
Duration predictor module.
This is a module of duration predictor described
in `FastSpeech: Fast, Robust and Controllable Text to Speech`_.
The duration predictor predicts a duration of each frame in log domain
from the hidden embeddings of encoder.
.. _`FastSpeech: Fast, Robust and Controllable Text to Speech`:
https://arxiv.org/pdf/1905.09263.pdf
Note:
The calculation domain of outputs is different
between in `forward` and in `inference`. In `forward`,
the outputs are calculated in log domain but in `inference`,
those are calculated in linear domain.
"""
def __init__(self, idim, n_layers=2, n_chans=384, kernel_size=3, dropout_rate=0.1, offset=1.0):
"""
Initialize duration predictor module.
Args:
idim (int): Input dimension.
n_layers (int, optional): Number of convolutional layers.
n_chans (int, optional): Number of channels of convolutional layers.
kernel_size (int, optional): Kernel size of convolutional layers.
dropout_rate (float, optional): Dropout rate.
offset (float, optional): Offset value to avoid nan in log domain.
"""
super(DurationPredictor, self).__init__()
self.offset = offset
self.conv = torch.nn.ModuleList()
for idx in range(n_layers):
in_chans = idim if idx == 0 else n_chans
self.conv += [torch.nn.Sequential(torch.nn.Conv1d(in_chans, n_chans, kernel_size, stride=1, padding=(kernel_size - 1) // 2, ), torch.nn.ReLU(),
LayerNorm(n_chans, dim=1), torch.nn.Dropout(dropout_rate), )]
self.linear = torch.nn.Linear(n_chans, 1)
def _forward(self, xs, x_masks=None, is_inference=False):
xs = xs.transpose(1, -1) # (B, idim, Tmax)
for f in self.conv:
xs = f(xs) # (B, C, Tmax)
# NOTE: calculate in log domain
xs = self.linear(xs.transpose(1, -1)).squeeze(-1) # (B, Tmax)
if is_inference:
# NOTE: calculate in linear domain
xs = torch.clamp(torch.round(xs.exp() - self.offset), min=0).long() # avoid negative value
if x_masks is not None:
xs = xs.masked_fill(x_masks, 0.0)
return xs
def forward(self, xs, x_masks=None):
"""
Calculate forward propagation.
Args:
xs (Tensor): Batch of input sequences (B, Tmax, idim).
x_masks (ByteTensor, optional):
Batch of masks indicating padded part (B, Tmax).
Returns:
Tensor: Batch of predicted durations in log domain (B, Tmax).
"""
return self._forward(xs, x_masks, False)
def inference(self, xs, x_masks=None):
"""
Inference duration.
Args:
xs (Tensor): Batch of input sequences (B, Tmax, idim).
x_masks (ByteTensor, optional):
Batch of masks indicating padded part (B, Tmax).
Returns:
LongTensor: Batch of predicted durations in linear domain (B, Tmax).
"""
return self._forward(xs, x_masks, True)
class DurationPredictorLoss(torch.nn.Module):
"""
Loss function module for duration predictor.
The loss value is Calculated in log domain to make it Gaussian.
"""
def __init__(self, offset=1.0, reduction="mean"):
"""
Args:
offset (float, optional): Offset value to avoid nan in log domain.
reduction (str): Reduction type in loss calculation.
"""
super(DurationPredictorLoss, self).__init__()
self.criterion = torch.nn.MSELoss(reduction=reduction)
self.offset = offset
def forward(self, outputs, targets):
"""
Calculate forward propagation.
Args:
outputs (Tensor): Batch of prediction durations in log domain (B, T)
targets (LongTensor): Batch of groundtruth durations in linear domain (B, T)
Returns:
Tensor: Mean squared error loss value.
Note:
`outputs` is in log domain but `targets` is in linear domain.
"""
# NOTE: outputs is in log domain while targets in linear
targets = torch.log(targets.float() + self.offset)
loss = self.criterion(outputs, targets)
return loss