from typing import Tuple
import numpy as np
import torch
from torch.nn import functional as F
from torch_complex.tensor import ComplexTensor
from espnet.nets.pytorch_backend.nets_utils import make_pad_mask
from espnet.nets.pytorch_backend.rnn.encoders import RNN, RNNP
[docs]class MaskEstimator(torch.nn.Module):
def __init__(self, type, idim, layers, units, projs, dropout, nmask=1):
super().__init__()
subsample = np.ones(layers + 1, dtype=np.int64)
typ = type.lstrip("vgg").rstrip("p")
if type[-1] == "p":
self.brnn = RNNP(idim, layers, units, projs, subsample, dropout, typ=typ)
else:
self.brnn = RNN(idim, layers, units, projs, dropout, typ=typ)
self.type = type
self.nmask = nmask
self.linears = torch.nn.ModuleList(
[torch.nn.Linear(projs, idim) for _ in range(nmask)]
)
[docs] def forward(
self, xs: ComplexTensor, ilens: torch.LongTensor
) -> Tuple[Tuple[torch.Tensor, ...], torch.LongTensor]:
"""The forward function
Args:
xs: (B, F, C, T)
ilens: (B,)
Returns:
hs (torch.Tensor): The hidden vector (B, F, C, T)
masks: A tuple of the masks. (B, F, C, T)
ilens: (B,)
"""
assert xs.size(0) == ilens.size(0), (xs.size(0), ilens.size(0))
_, _, C, input_length = xs.size()
# (B, F, C, T) -> (B, C, T, F)
xs = xs.permute(0, 2, 3, 1)
# Calculate amplitude: (B, C, T, F) -> (B, C, T, F)
xs = (xs.real**2 + xs.imag**2) ** 0.5
# xs: (B, C, T, F) -> xs: (B * C, T, F)
xs = xs.contiguous().view(-1, xs.size(-2), xs.size(-1))
# ilens: (B,) -> ilens_: (B * C)
ilens_ = ilens[:, None].expand(-1, C).contiguous().view(-1)
# xs: (B * C, T, F) -> xs: (B * C, T, D)
xs, _, _ = self.brnn(xs, ilens_)
# xs: (B * C, T, D) -> xs: (B, C, T, D)
xs = xs.view(-1, C, xs.size(-2), xs.size(-1))
masks = []
for linear in self.linears:
# xs: (B, C, T, D) -> mask:(B, C, T, F)
mask = linear(xs)
mask = torch.sigmoid(mask)
# Zero padding
mask.masked_fill(make_pad_mask(ilens, mask, length_dim=2), 0)
# (B, C, T, F) -> (B, F, C, T)
mask = mask.permute(0, 3, 1, 2)
# Take cares of multi gpu cases: If input_length > max(ilens)
if mask.size(-1) < input_length:
mask = F.pad(mask, [0, input_length - mask.size(-1)], value=0)
masks.append(mask)
return tuple(masks), ilens