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# code adapted from: https://github.com/Stability-AI/stable-audio-tools
import torch
from torch import nn
from typing import Literal, Dict, Any
import math
import comfy.ops
ops = comfy.ops.disable_weight_init
def vae_sample(mean, scale):
stdev = nn.functional.softplus(scale) + 1e-4
var = stdev * stdev
logvar = torch.log(var)
latents = torch.randn_like(mean) * stdev + mean
kl = (mean * mean + var - logvar - 1).sum(1).mean()
return latents, kl
class VAEBottleneck(nn.Module):
def __init__(self):
super().__init__()
self.is_discrete = False
def encode(self, x, return_info=False, **kwargs):
info = {}
mean, scale = x.chunk(2, dim=1)
x, kl = vae_sample(mean, scale)
info["kl"] = kl
if return_info:
return x, info
else:
return x
def decode(self, x):
return x
def snake_beta(x, alpha, beta):
return x + (1.0 / (beta + 0.000000001)) * pow(torch.sin(x * alpha), 2)
# Adapted from https://github.com/NVIDIA/BigVGAN/blob/main/activations.py under MIT license
class SnakeBeta(nn.Module):
def __init__(self, in_features, alpha=1.0, alpha_trainable=True, alpha_logscale=True):
super(SnakeBeta, self).__init__()
self.in_features = in_features
# initialize alpha
self.alpha_logscale = alpha_logscale
if self.alpha_logscale: # log scale alphas initialized to zeros
self.alpha = nn.Parameter(torch.zeros(in_features) * alpha)
self.beta = nn.Parameter(torch.zeros(in_features) * alpha)
else: # linear scale alphas initialized to ones
self.alpha = nn.Parameter(torch.ones(in_features) * alpha)
self.beta = nn.Parameter(torch.ones(in_features) * alpha)
# self.alpha.requires_grad = alpha_trainable
# self.beta.requires_grad = alpha_trainable
self.no_div_by_zero = 0.000000001
def forward(self, x):
alpha = self.alpha.unsqueeze(0).unsqueeze(-1).to(x.device) # line up with x to [B, C, T]
beta = self.beta.unsqueeze(0).unsqueeze(-1).to(x.device)
if self.alpha_logscale:
alpha = torch.exp(alpha)
beta = torch.exp(beta)
x = snake_beta(x, alpha, beta)
return x
def WNConv1d(*args, **kwargs):
try:
return torch.nn.utils.parametrizations.weight_norm(ops.Conv1d(*args, **kwargs))
except:
return torch.nn.utils.weight_norm(ops.Conv1d(*args, **kwargs)) #support pytorch 2.1 and older
def WNConvTranspose1d(*args, **kwargs):
try:
return torch.nn.utils.parametrizations.weight_norm(ops.ConvTranspose1d(*args, **kwargs))
except:
return torch.nn.utils.weight_norm(ops.ConvTranspose1d(*args, **kwargs)) #support pytorch 2.1 and older
def get_activation(activation: Literal["elu", "snake", "none"], antialias=False, channels=None) -> nn.Module:
if activation == "elu":
act = torch.nn.ELU()
elif activation == "snake":
act = SnakeBeta(channels)
elif activation == "none":
act = torch.nn.Identity()
else:
raise ValueError(f"Unknown activation {activation}")
if antialias:
act = Activation1d(act)
return act
class ResidualUnit(nn.Module):
def __init__(self, in_channels, out_channels, dilation, use_snake=False, antialias_activation=False):
super().__init__()
self.dilation = dilation
padding = (dilation * (7-1)) // 2
self.layers = nn.Sequential(
get_activation("snake" if use_snake else "elu", antialias=antialias_activation, channels=out_channels),
WNConv1d(in_channels=in_channels, out_channels=out_channels,
kernel_size=7, dilation=dilation, padding=padding),
get_activation("snake" if use_snake else "elu", antialias=antialias_activation, channels=out_channels),
WNConv1d(in_channels=out_channels, out_channels=out_channels,
kernel_size=1)
)
def forward(self, x):
res = x
#x = checkpoint(self.layers, x)
x = self.layers(x)
return x + res
class EncoderBlock(nn.Module):
def __init__(self, in_channels, out_channels, stride, use_snake=False, antialias_activation=False):
super().__init__()
self.layers = nn.Sequential(
ResidualUnit(in_channels=in_channels,
out_channels=in_channels, dilation=1, use_snake=use_snake),
ResidualUnit(in_channels=in_channels,
out_channels=in_channels, dilation=3, use_snake=use_snake),
ResidualUnit(in_channels=in_channels,
out_channels=in_channels, dilation=9, use_snake=use_snake),
get_activation("snake" if use_snake else "elu", antialias=antialias_activation, channels=in_channels),
WNConv1d(in_channels=in_channels, out_channels=out_channels,
kernel_size=2*stride, stride=stride, padding=math.ceil(stride/2)),
)
def forward(self, x):
return self.layers(x)
class DecoderBlock(nn.Module):
def __init__(self, in_channels, out_channels, stride, use_snake=False, antialias_activation=False, use_nearest_upsample=False):
super().__init__()
if use_nearest_upsample:
upsample_layer = nn.Sequential(
nn.Upsample(scale_factor=stride, mode="nearest"),
WNConv1d(in_channels=in_channels,
out_channels=out_channels,
kernel_size=2*stride,
stride=1,
bias=False,
padding='same')
)
else:
upsample_layer = WNConvTranspose1d(in_channels=in_channels,
out_channels=out_channels,
kernel_size=2*stride, stride=stride, padding=math.ceil(stride/2))
self.layers = nn.Sequential(
get_activation("snake" if use_snake else "elu", antialias=antialias_activation, channels=in_channels),
upsample_layer,
ResidualUnit(in_channels=out_channels, out_channels=out_channels,
dilation=1, use_snake=use_snake),
ResidualUnit(in_channels=out_channels, out_channels=out_channels,
dilation=3, use_snake=use_snake),
ResidualUnit(in_channels=out_channels, out_channels=out_channels,
dilation=9, use_snake=use_snake),
)
def forward(self, x):
return self.layers(x)
class OobleckEncoder(nn.Module):
def __init__(self,
in_channels=2,
channels=128,
latent_dim=32,
c_mults = [1, 2, 4, 8],
strides = [2, 4, 8, 8],
use_snake=False,
antialias_activation=False
):
super().__init__()
c_mults = [1] + c_mults
self.depth = len(c_mults)
layers = [
WNConv1d(in_channels=in_channels, out_channels=c_mults[0] * channels, kernel_size=7, padding=3)
]
for i in range(self.depth-1):
layers += [EncoderBlock(in_channels=c_mults[i]*channels, out_channels=c_mults[i+1]*channels, stride=strides[i], use_snake=use_snake)]
layers += [
get_activation("snake" if use_snake else "elu", antialias=antialias_activation, channels=c_mults[-1] * channels),
WNConv1d(in_channels=c_mults[-1]*channels, out_channels=latent_dim, kernel_size=3, padding=1)
]
self.layers = nn.Sequential(*layers)
def forward(self, x):
return self.layers(x)
class OobleckDecoder(nn.Module):
def __init__(self,
out_channels=2,
channels=128,
latent_dim=32,
c_mults = [1, 2, 4, 8],
strides = [2, 4, 8, 8],
use_snake=False,
antialias_activation=False,
use_nearest_upsample=False,
final_tanh=True):
super().__init__()
c_mults = [1] + c_mults
self.depth = len(c_mults)
layers = [
WNConv1d(in_channels=latent_dim, out_channels=c_mults[-1]*channels, kernel_size=7, padding=3),
]
for i in range(self.depth-1, 0, -1):
layers += [DecoderBlock(
in_channels=c_mults[i]*channels,
out_channels=c_mults[i-1]*channels,
stride=strides[i-1],
use_snake=use_snake,
antialias_activation=antialias_activation,
use_nearest_upsample=use_nearest_upsample
)
]
layers += [
get_activation("snake" if use_snake else "elu", antialias=antialias_activation, channels=c_mults[0] * channels),
WNConv1d(in_channels=c_mults[0] * channels, out_channels=out_channels, kernel_size=7, padding=3, bias=False),
nn.Tanh() if final_tanh else nn.Identity()
]
self.layers = nn.Sequential(*layers)
def forward(self, x):
return self.layers(x)
class AudioOobleckVAE(nn.Module):
def __init__(self,
in_channels=2,
channels=128,
latent_dim=64,
c_mults = [1, 2, 4, 8, 16],
strides = [2, 4, 4, 8, 8],
use_snake=True,
antialias_activation=False,
use_nearest_upsample=False,
final_tanh=False):
super().__init__()
self.encoder = OobleckEncoder(in_channels, channels, latent_dim * 2, c_mults, strides, use_snake, antialias_activation)
self.decoder = OobleckDecoder(in_channels, channels, latent_dim, c_mults, strides, use_snake, antialias_activation,
use_nearest_upsample=use_nearest_upsample, final_tanh=final_tanh)
self.bottleneck = VAEBottleneck()
def encode(self, x):
return self.bottleneck.encode(self.encoder(x))
def decode(self, x):
return self.decoder(self.bottleneck.decode(x))
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