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import math
import random
import torch
from torch import nn
from torch.nn import functional as F
import numpy as np
from models.stylegan2.op import FusedLeakyReLU, fused_leaky_relu, upfirdn2d
class PixelNorm(nn.Module):
def __init__(self):
super().__init__()
def forward(self, input):
return input * torch.rsqrt(torch.mean(input ** 2, dim=1, keepdim=True) + 1e-8)
def make_kernel(k):
k = torch.tensor(k, dtype=torch.float32)
if k.ndim == 1:
k = k[None, :] * k[:, None]
k /= k.sum()
return k
class Upsample(nn.Module):
def __init__(self, kernel, factor=2):
super().__init__()
self.factor = factor
kernel = make_kernel(kernel) * (factor ** 2)
self.register_buffer('kernel', kernel)
p = kernel.shape[0] - factor
pad0 = (p + 1) // 2 + factor - 1
pad1 = p // 2
self.pad = (pad0, pad1)
def forward(self, input):
out = upfirdn2d(input, self.kernel, up=self.factor, down=1, pad=self.pad)
return out
class Downsample(nn.Module):
def __init__(self, kernel, factor=2):
super().__init__()
self.factor = factor
kernel = make_kernel(kernel)
self.register_buffer('kernel', kernel)
p = kernel.shape[0] - factor
pad0 = (p + 1) // 2
pad1 = p // 2
self.pad = (pad0, pad1)
def forward(self, input):
out = upfirdn2d(input, self.kernel, up=1, down=self.factor, pad=self.pad)
return out
class Blur(nn.Module):
def __init__(self, kernel, pad, upsample_factor=1):
super().__init__()
kernel = make_kernel(kernel)
if upsample_factor > 1:
kernel = kernel * (upsample_factor ** 2)
self.register_buffer('kernel', kernel)
self.pad = pad
def forward(self, input):
out = upfirdn2d(input, self.kernel, pad=self.pad)
return out
class EqualConv2d(nn.Module):
def __init__(
self, in_channel, out_channel, kernel_size, stride=1, padding=0, bias=True, dilation=1 ## modified
):
super().__init__()
self.weight = nn.Parameter(
torch.randn(out_channel, in_channel, kernel_size, kernel_size)
)
self.scale = 1 / math.sqrt(in_channel * kernel_size ** 2)
self.stride = stride
self.padding = padding
self.dilation = dilation ## modified
if bias:
self.bias = nn.Parameter(torch.zeros(out_channel))
else:
self.bias = None
def forward(self, input):
out = F.conv2d(
input,
self.weight * self.scale,
bias=self.bias,
stride=self.stride,
padding=self.padding,
dilation=self.dilation, ## modified
)
return out
def __repr__(self):
return (
f"{self.__class__.__name__}({self.weight.shape[1]}, {self.weight.shape[0]},"
f" {self.weight.shape[2]}, stride={self.stride}, padding={self.padding}, dilation={self.dilation})" ## modified
)
class EqualLinear(nn.Module):
def __init__(
self, in_dim, out_dim, bias=True, bias_init=0, lr_mul=1, activation=None
):
super().__init__()
self.weight = nn.Parameter(torch.randn(out_dim, in_dim).div_(lr_mul))
if bias:
self.bias = nn.Parameter(torch.zeros(out_dim).fill_(bias_init))
else:
self.bias = None
self.activation = activation
self.scale = (1 / math.sqrt(in_dim)) * lr_mul
self.lr_mul = lr_mul
def forward(self, input):
if self.activation:
out = F.linear(input, self.weight * self.scale)
out = fused_leaky_relu(out, self.bias * self.lr_mul)
else:
out = F.linear(
input, self.weight * self.scale, bias=self.bias * self.lr_mul
)
return out
def __repr__(self):
return (
f'{self.__class__.__name__}({self.weight.shape[1]}, {self.weight.shape[0]})'
)
class ScaledLeakyReLU(nn.Module):
def __init__(self, negative_slope=0.2):
super().__init__()
self.negative_slope = negative_slope
def forward(self, input):
out = F.leaky_relu(input, negative_slope=self.negative_slope)
return out * math.sqrt(2)
class ModulatedConv2d(nn.Module):
def __init__(
self,
in_channel,
out_channel,
kernel_size,
style_dim,
demodulate=True,
upsample=False,
downsample=False,
blur_kernel=[1, 3, 3, 1],
dilation=1, ##### modified
):
super().__init__()
self.eps = 1e-8
self.kernel_size = kernel_size
self.in_channel = in_channel
self.out_channel = out_channel
self.upsample = upsample
self.downsample = downsample
self.dilation = dilation ##### modified
if upsample:
factor = 2
p = (len(blur_kernel) - factor) - (kernel_size - 1)
pad0 = (p + 1) // 2 + factor - 1
pad1 = p // 2 + 1
self.blur = Blur(blur_kernel, pad=(pad0, pad1), upsample_factor=factor)
# to simulate transconv + blur
# we use dilated transposed conv with blur kernel as weight + dilated transconv
if dilation > 1: ##### modified
blur_weight = torch.randn(1, 1, 3, 3) * 0 + 1
blur_weight[:,:,0,1] = 2
blur_weight[:,:,1,0] = 2
blur_weight[:,:,1,2] = 2
blur_weight[:,:,2,1] = 2
blur_weight[:,:,1,1] = 4
blur_weight = blur_weight / 16.0
self.register_buffer("blur_weight", blur_weight)
if downsample:
factor = 2
p = (len(blur_kernel) - factor) + (kernel_size - 1)
pad0 = (p + 1) // 2
pad1 = p // 2
self.blur = Blur(blur_kernel, pad=(pad0, pad1))
fan_in = in_channel * kernel_size ** 2
self.scale = 1 / math.sqrt(fan_in)
self.padding = kernel_size // 2 + dilation - 1 ##### modified
self.weight = nn.Parameter(
torch.randn(1, out_channel, in_channel, kernel_size, kernel_size)
)
self.modulation = EqualLinear(style_dim, in_channel, bias_init=1)
self.demodulate = demodulate
def __repr__(self):
return (
f'{self.__class__.__name__}({self.in_channel}, {self.out_channel}, {self.kernel_size}, '
f'upsample={self.upsample}, downsample={self.downsample})'
)
def forward(self, input, style):
batch, in_channel, height, width = input.shape
style = self.modulation(style).view(batch, 1, in_channel, 1, 1)
weight = self.scale * self.weight * style
if self.demodulate:
demod = torch.rsqrt(weight.pow(2).sum([2, 3, 4]) + 1e-8)
weight = weight * demod.view(batch, self.out_channel, 1, 1, 1)
weight = weight.view(
batch * self.out_channel, in_channel, self.kernel_size, self.kernel_size
)
if self.upsample:
input = input.view(1, batch * in_channel, height, width)
weight = weight.view(
batch, self.out_channel, in_channel, self.kernel_size, self.kernel_size
)
weight = weight.transpose(1, 2).reshape(
batch * in_channel, self.out_channel, self.kernel_size, self.kernel_size
)
if self.dilation > 1: ##### modified
# to simulate out = self.blur(out)
out = F.conv_transpose2d(
input, self.blur_weight.repeat(batch*in_channel,1,1,1), padding=0, groups=batch*in_channel, dilation=self.dilation//2)
# to simulate the next line
out = F.conv_transpose2d(
out, weight, padding=self.dilation, groups=batch, dilation=self.dilation//2)
_, _, height, width = out.shape
out = out.view(batch, self.out_channel, height, width)
return out
out = F.conv_transpose2d(input, weight, padding=0, stride=2, groups=batch)
_, _, height, width = out.shape
out = out.view(batch, self.out_channel, height, width)
out = self.blur(out)
elif self.downsample:
input = self.blur(input)
_, _, height, width = input.shape
input = input.view(1, batch * in_channel, height, width)
out = F.conv2d(input, weight, padding=0, stride=2, groups=batch)
_, _, height, width = out.shape
out = out.view(batch, self.out_channel, height, width)
else:
input = input.view(1, batch * in_channel, height, width)
out = F.conv2d(input, weight, padding=self.padding, groups=batch, dilation=self.dilation) ##### modified
_, _, height, width = out.shape
out = out.view(batch, self.out_channel, height, width)
return out
class NoiseInjection(nn.Module):
def __init__(self):
super().__init__()
self.weight = nn.Parameter(torch.zeros(1))
def forward(self, image, noise=None):
if noise is None:
batch, _, height, width = image.shape
noise = image.new_empty(batch, 1, height, width).normal_()
else: ##### modified, to make the resolution matches
batch, _, height, width = image.shape
_, _, height1, width1 = noise.shape
if height != height1 or width != width1:
noise = F.adaptive_avg_pool2d(noise, (height, width))
return image + self.weight * noise
class ConstantInput(nn.Module):
def __init__(self, channel, size=4):
super().__init__()
self.input = nn.Parameter(torch.randn(1, channel, size, size))
def forward(self, input):
batch = input.shape[0]
out = self.input.repeat(batch, 1, 1, 1)
return out
class StyledConv(nn.Module):
def __init__(
self,
in_channel,
out_channel,
kernel_size,
style_dim,
upsample=False,
blur_kernel=[1, 3, 3, 1],
demodulate=True,
dilation=1, ##### modified
):
super().__init__()
self.conv = ModulatedConv2d(
in_channel,
out_channel,
kernel_size,
style_dim,
upsample=upsample,
blur_kernel=blur_kernel,
demodulate=demodulate,
dilation=dilation, ##### modified
)
self.noise = NoiseInjection()
self.activate = FusedLeakyReLU(out_channel)
def forward(self, input, style, noise=None):
out = self.conv(input, style)
out = self.noise(out, noise=noise)
out = self.activate(out)
return out
class ToRGB(nn.Module):
def __init__(self, in_channel, style_dim, upsample=True, blur_kernel=[1, 3, 3, 1], dilation=1): ##### modified
super().__init__()
if upsample:
self.upsample = Upsample(blur_kernel)
self.conv = ModulatedConv2d(in_channel, 3, 1, style_dim, demodulate=False)
self.bias = nn.Parameter(torch.zeros(1, 3, 1, 1))
self.dilation = dilation ##### modified
if dilation > 1: ##### modified
blur_weight = torch.randn(1, 1, 3, 3) * 0 + 1
blur_weight[:,:,0,1] = 2
blur_weight[:,:,1,0] = 2
blur_weight[:,:,1,2] = 2
blur_weight[:,:,2,1] = 2
blur_weight[:,:,1,1] = 4
blur_weight = blur_weight / 16.0
self.register_buffer("blur_weight", blur_weight)
def forward(self, input, style, skip=None):
out = self.conv(input, style)
out = out + self.bias
if skip is not None:
if self.dilation == 1:
skip = self.upsample(skip)
else: ##### modified, to simulate skip = self.upsample(skip)
batch, in_channel, _, _ = skip.shape
skip = F.conv2d(skip, self.blur_weight.repeat(in_channel,1,1,1),
padding=self.dilation//2, groups=in_channel, dilation=self.dilation//2)
out = out + skip
return out
class Generator(nn.Module):
def __init__(
self,
size,
style_dim,
n_mlp,
channel_multiplier=2,
blur_kernel=[1, 3, 3, 1],
lr_mlp=0.01,
):
super().__init__()
self.size = size
self.style_dim = style_dim
layers = [PixelNorm()]
for i in range(n_mlp):
layers.append(
EqualLinear(
style_dim, style_dim, lr_mul=lr_mlp, activation='fused_lrelu'
)
)
self.style = nn.Sequential(*layers)
self.channels = {
4: 512,
8: 512,
16: 512,
32: 512,
64: 256 * channel_multiplier,
128: 128 * channel_multiplier,
256: 64 * channel_multiplier,
512: 32 * channel_multiplier,
1024: 16 * channel_multiplier,
}
self.input = ConstantInput(self.channels[4])
self.conv1 = StyledConv(
self.channels[4], self.channels[4], 3, style_dim, blur_kernel=blur_kernel, dilation=8 ##### modified
)
self.to_rgb1 = ToRGB(self.channels[4], style_dim, upsample=False)
self.log_size = int(math.log(size, 2))
self.num_layers = (self.log_size - 2) * 2 + 1
self.convs = nn.ModuleList()
self.upsamples = nn.ModuleList()
self.to_rgbs = nn.ModuleList()
self.noises = nn.Module()
in_channel = self.channels[4]
for layer_idx in range(self.num_layers):
res = (layer_idx + 5) // 2
shape = [1, 1, 2 ** res, 2 ** res]
self.noises.register_buffer(f'noise_{layer_idx}', torch.randn(*shape))
for i in range(3, self.log_size + 1):
out_channel = self.channels[2 ** i]
self.convs.append(
StyledConv(
in_channel,
out_channel,
3,
style_dim,
upsample=True,
blur_kernel=blur_kernel,
dilation=max(1, 32 // (2**(i-1))) ##### modified
)
)
self.convs.append(
StyledConv(
out_channel, out_channel, 3, style_dim, blur_kernel=blur_kernel, dilation=max(1, 32 // (2**i)) ##### modified
)
)
self.to_rgbs.append(ToRGB(out_channel, style_dim, dilation=max(1, 32 // (2**(i-1))))) ##### modified
in_channel = out_channel
self.n_latent = self.log_size * 2 - 2
def make_noise(self):
device = self.input.input.device
noises = [torch.randn(1, 1, 2 ** 2, 2 ** 2, device=device)]
for i in range(3, self.log_size + 1):
for _ in range(2):
noises.append(torch.randn(1, 1, 2 ** i, 2 ** i, device=device))
return noises
def mean_latent(self, n_latent):
latent_in = torch.randn(
n_latent, self.style_dim, device=self.input.input.device
)
latent = self.style(latent_in).mean(0, keepdim=True)
return latent
def get_latent(self, input):
return self.style(input)
# styles is the latent code w+
# first_layer_feature is the first-layer input feature f
# first_layer_feature_ind indicate which layer of G accepts f (should always=0, the first layer)
# skip_layer_feature is the encoder features sent by skip connection
# fusion_block is the network to fuse the encoder feature and decoder feature
# zero_noise is to force the noise to be zero (to avoid flickers for videos)
# editing_w is the editing vector v used in video face editing
def forward(
self,
styles,
return_latents=False,
return_features=False,
inject_index=None,
truncation=1,
truncation_latent=None,
input_is_latent=False,
noise=None,
randomize_noise=True,
first_layer_feature = None, ##### modified
first_layer_feature_ind = 0, ##### modified
skip_layer_feature = None, ##### modified
fusion_block = None, ##### modified
zero_noise = False, ##### modified
editing_w = None, ##### modified
):
if not input_is_latent:
styles = [self.style(s) for s in styles]
if zero_noise:
noise = [
getattr(self.noises, f'noise_{i}') * 0.0 for i in range(self.num_layers)
]
elif noise is None:
if randomize_noise:
noise = [None] * self.num_layers
else:
noise = [
getattr(self.noises, f'noise_{i}') for i in range(self.num_layers)
]
if truncation < 1:
style_t = []
for style in styles:
style_t.append(
truncation_latent + truncation * (style - truncation_latent)
)
styles = style_t
if len(styles) < 2:
inject_index = self.n_latent
if styles[0].ndim < 3:
latent = styles[0].unsqueeze(1).repeat(1, inject_index, 1)
else:
latent = styles[0]
else:
if inject_index is None:
inject_index = random.randint(1, self.n_latent - 1)
latent = styles[0].unsqueeze(1).repeat(1, inject_index, 1)
latent2 = styles[1].unsqueeze(1).repeat(1, self.n_latent - inject_index, 1)
latent = torch.cat([latent, latent2], 1)
# w+ + v for video face editing
if editing_w is not None: ##### modified
latent = latent + editing_w
# the original StyleGAN
if first_layer_feature is None: ##### modified
out = self.input(latent)
out = F.adaptive_avg_pool2d(out, 32) ##### modified
out = self.conv1(out, latent[:, 0], noise=noise[0])
skip = self.to_rgb1(out, latent[:, 1])
# the default StyleGANEX, replacing the first layer of G
elif first_layer_feature_ind == 0: ##### modified
out = first_layer_feature[0] ##### modified
out = self.conv1(out, latent[:, 0], noise=noise[0])
skip = self.to_rgb1(out, latent[:, 1])
# maybe we can also use the second layer of G to accept f?
else: ##### modified
out = first_layer_feature[0] ##### modified
skip = first_layer_feature[1] ##### modified
i = 1
for conv1, conv2, noise1, noise2, to_rgb in zip(
self.convs[::2], self.convs[1::2], noise[1::2], noise[2::2], self.to_rgbs
):
# these layers accepts skipped encoder layer, use fusion block to fuse the encoder feature and decoder feature
if skip_layer_feature and fusion_block and i//2 < len(skip_layer_feature) and i//2 < len(fusion_block):
if editing_w is None:
out, skip = fusion_block[i//2](skip_layer_feature[i//2], out, skip)
else:
out, skip = fusion_block[i//2](skip_layer_feature[i//2], out, skip, editing_w[:,i])
out = conv1(out, latent[:, i], noise=noise1)
out = conv2(out, latent[:, i + 1], noise=noise2)
skip = to_rgb(out, latent[:, i + 2], skip)
i += 2
image = skip
if return_latents:
return image, latent
elif return_features:
return image, out
else:
return image, None
class ConvLayer(nn.Sequential):
def __init__(
self,
in_channel,
out_channel,
kernel_size,
downsample=False,
blur_kernel=[1, 3, 3, 1],
bias=True,
activate=True,
dilation=1, ## modified
):
layers = []
if downsample:
factor = 2
p = (len(blur_kernel) - factor) + (kernel_size - 1)
pad0 = (p + 1) // 2
pad1 = p // 2
layers.append(Blur(blur_kernel, pad=(pad0, pad1)))
stride = 2
self.padding = 0
else:
stride = 1
self.padding = kernel_size // 2 + dilation-1 ## modified
layers.append(
EqualConv2d(
in_channel,
out_channel,
kernel_size,
padding=self.padding,
stride=stride,
bias=bias and not activate,
dilation=dilation, ## modified
)
)
if activate:
if bias:
layers.append(FusedLeakyReLU(out_channel))
else:
layers.append(ScaledLeakyReLU(0.2))
super().__init__(*layers)
class ResBlock(nn.Module):
def __init__(self, in_channel, out_channel, blur_kernel=[1, 3, 3, 1]):
super().__init__()
self.conv1 = ConvLayer(in_channel, in_channel, 3)
self.conv2 = ConvLayer(in_channel, out_channel, 3, downsample=True)
self.skip = ConvLayer(
in_channel, out_channel, 1, downsample=True, activate=False, bias=False
)
def forward(self, input):
out = self.conv1(input)
out = self.conv2(out)
skip = self.skip(input)
out = (out + skip) / math.sqrt(2)
return out
class Discriminator(nn.Module):
def __init__(self, size, channel_multiplier=2, blur_kernel=[1, 3, 3, 1], img_channel=3):
super().__init__()
channels = {
4: 512,
8: 512,
16: 512,
32: 512,
64: 256 * channel_multiplier,
128: 128 * channel_multiplier,
256: 64 * channel_multiplier,
512: 32 * channel_multiplier,
1024: 16 * channel_multiplier,
}
convs = [ConvLayer(img_channel, channels[size], 1)]
log_size = int(math.log(size, 2))
in_channel = channels[size]
for i in range(log_size, 2, -1):
out_channel = channels[2 ** (i - 1)]
convs.append(ResBlock(in_channel, out_channel, blur_kernel))
in_channel = out_channel
self.convs = nn.Sequential(*convs)
self.stddev_group = 4
self.stddev_feat = 1
self.final_conv = ConvLayer(in_channel + 1, channels[4], 3)
self.final_linear = nn.Sequential(
EqualLinear(channels[4] * 4 * 4, channels[4], activation='fused_lrelu'),
EqualLinear(channels[4], 1),
)
self.size = size ##### modified
def forward(self, input):
# for input that not satisfies the target size, we crop it to extract a small image of the target size.
_, _, h, w = input.shape ##### modified
i, j = torch.randint(0, h+1-self.size, size=(1,)).item(), torch.randint(0, w+1-self.size, size=(1,)).item() ##### modified
out = self.convs(input[:,:,i:i+self.size,j:j+self.size]) ##### modified
batch, channel, height, width = out.shape
group = min(batch, self.stddev_group)
stddev = out.view(
group, -1, self.stddev_feat, channel // self.stddev_feat, height, width
)
stddev = torch.sqrt(stddev.var(0, unbiased=False) + 1e-8)
stddev = stddev.mean([2, 3, 4], keepdims=True).squeeze(2)
stddev = stddev.repeat(group, 1, height, width)
out = torch.cat([out, stddev], 1)
out = self.final_conv(out)
out = out.view(batch, -1)
out = self.final_linear(out)
return out