Spaces:
Running
Running
File size: 3,309 Bytes
0883aa1 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 |
# Copyright (c) 2023 Amphion.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
import torch
import torch.nn as nn
import torch.nn.functional as F
import math
if "sinc" in dir(torch):
sinc = torch.sinc
else:
# This code is adopted from adefossez's julius.core.sinc under the MIT License
# https://adefossez.github.io/julius/julius/core.html
def sinc(x: torch.Tensor):
"""
Implementation of sinc, i.e. sin(pi * x) / (pi * x)
__Warning__: Different to julius.sinc, the input is multiplied by `pi`!
"""
return torch.where(
x == 0,
torch.tensor(1.0, device=x.device, dtype=x.dtype),
torch.sin(math.pi * x) / math.pi / x,
)
# This code is adopted from adefossez's julius.lowpass.LowPassFilters under the MIT License
# https://adefossez.github.io/julius/julius/lowpass.html
def kaiser_sinc_filter1d(
cutoff, half_width, kernel_size
): # return filter [1,1,kernel_size]
even = kernel_size % 2 == 0
half_size = kernel_size // 2
# For kaiser window
delta_f = 4 * half_width
A = 2.285 * (half_size - 1) * math.pi * delta_f + 7.95
if A > 50.0:
beta = 0.1102 * (A - 8.7)
elif A >= 21.0:
beta = 0.5842 * (A - 21) ** 0.4 + 0.07886 * (A - 21.0)
else:
beta = 0.0
window = torch.kaiser_window(kernel_size, beta=beta, periodic=False)
# ratio = 0.5/cutoff -> 2 * cutoff = 1 / ratio
if even:
time = torch.arange(-half_size, half_size) + 0.5
else:
time = torch.arange(kernel_size) - half_size
if cutoff == 0:
filter_ = torch.zeros_like(time)
else:
filter_ = 2 * cutoff * window * sinc(2 * cutoff * time)
# Normalize filter to have sum = 1, otherwise we will have a small leakage
# of the constant component in the input signal.
filter_ /= filter_.sum()
filter = filter_.view(1, 1, kernel_size)
return filter
class LowPassFilter1d(nn.Module):
def __init__(
self,
cutoff=0.5,
half_width=0.6,
stride: int = 1,
padding: bool = True,
padding_mode: str = "replicate",
kernel_size: int = 12,
):
# kernel_size should be even number for stylegan3 setup,
# in this implementation, odd number is also possible.
super().__init__()
if cutoff < -0.0:
raise ValueError("Minimum cutoff must be larger than zero.")
if cutoff > 0.5:
raise ValueError("A cutoff above 0.5 does not make sense.")
self.kernel_size = kernel_size
self.even = kernel_size % 2 == 0
self.pad_left = kernel_size // 2 - int(self.even)
self.pad_right = kernel_size // 2
self.stride = stride
self.padding = padding
self.padding_mode = padding_mode
filter = kaiser_sinc_filter1d(cutoff, half_width, kernel_size)
self.register_buffer("filter", filter)
# input [B, C, T]
def forward(self, x):
_, C, _ = x.shape
if self.padding:
x = F.pad(x, (self.pad_left, self.pad_right), mode=self.padding_mode)
out = F.conv1d(x, self.filter.expand(C, -1, -1), stride=self.stride, groups=C)
return out
|