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# Copyright (c) 2022 Dominic Rampas MIT License
# Copyright 2023 The HuggingFace Team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import Union
import torch
import torch.nn as nn
from ...configuration_utils import ConfigMixin, register_to_config
from ...models.autoencoders.vae import DecoderOutput, VectorQuantizer
from ...models.modeling_utils import ModelMixin
from ...models.vq_model import VQEncoderOutput
from ...utils.accelerate_utils import apply_forward_hook
class MixingResidualBlock(nn.Module):
"""
Residual block with mixing used by Paella's VQ-VAE.
"""
def __init__(self, inp_channels, embed_dim):
super().__init__()
# depthwise
self.norm1 = nn.LayerNorm(inp_channels, elementwise_affine=False, eps=1e-6)
self.depthwise = nn.Sequential(
nn.ReplicationPad2d(1), nn.Conv2d(inp_channels, inp_channels, kernel_size=3, groups=inp_channels)
)
# channelwise
self.norm2 = nn.LayerNorm(inp_channels, elementwise_affine=False, eps=1e-6)
self.channelwise = nn.Sequential(
nn.Linear(inp_channels, embed_dim), nn.GELU(), nn.Linear(embed_dim, inp_channels)
)
self.gammas = nn.Parameter(torch.zeros(6), requires_grad=True)
def forward(self, x):
mods = self.gammas
x_temp = self.norm1(x.permute(0, 2, 3, 1)).permute(0, 3, 1, 2) * (1 + mods[0]) + mods[1]
x = x + self.depthwise(x_temp) * mods[2]
x_temp = self.norm2(x.permute(0, 2, 3, 1)).permute(0, 3, 1, 2) * (1 + mods[3]) + mods[4]
x = x + self.channelwise(x_temp.permute(0, 2, 3, 1)).permute(0, 3, 1, 2) * mods[5]
return x
class PaellaVQModel(ModelMixin, ConfigMixin):
r"""VQ-VAE model from Paella model.
This model inherits from [`ModelMixin`]. Check the superclass documentation for the generic methods the library
implements for all the model (such as downloading or saving, etc.)
Parameters:
in_channels (int, *optional*, defaults to 3): Number of channels in the input image.
out_channels (int, *optional*, defaults to 3): Number of channels in the output.
up_down_scale_factor (int, *optional*, defaults to 2): Up and Downscale factor of the input image.
levels (int, *optional*, defaults to 2): Number of levels in the model.
bottleneck_blocks (int, *optional*, defaults to 12): Number of bottleneck blocks in the model.
embed_dim (int, *optional*, defaults to 384): Number of hidden channels in the model.
latent_channels (int, *optional*, defaults to 4): Number of latent channels in the VQ-VAE model.
num_vq_embeddings (int, *optional*, defaults to 8192): Number of codebook vectors in the VQ-VAE.
scale_factor (float, *optional*, defaults to 0.3764): Scaling factor of the latent space.
"""
@register_to_config
def __init__(
self,
in_channels: int = 3,
out_channels: int = 3,
up_down_scale_factor: int = 2,
levels: int = 2,
bottleneck_blocks: int = 12,
embed_dim: int = 384,
latent_channels: int = 4,
num_vq_embeddings: int = 8192,
scale_factor: float = 0.3764,
):
super().__init__()
c_levels = [embed_dim // (2**i) for i in reversed(range(levels))]
# Encoder blocks
self.in_block = nn.Sequential(
nn.PixelUnshuffle(up_down_scale_factor),
nn.Conv2d(in_channels * up_down_scale_factor**2, c_levels[0], kernel_size=1),
)
down_blocks = []
for i in range(levels):
if i > 0:
down_blocks.append(nn.Conv2d(c_levels[i - 1], c_levels[i], kernel_size=4, stride=2, padding=1))
block = MixingResidualBlock(c_levels[i], c_levels[i] * 4)
down_blocks.append(block)
down_blocks.append(
nn.Sequential(
nn.Conv2d(c_levels[-1], latent_channels, kernel_size=1, bias=False),
nn.BatchNorm2d(latent_channels), # then normalize them to have mean 0 and std 1
)
)
self.down_blocks = nn.Sequential(*down_blocks)
# Vector Quantizer
self.vquantizer = VectorQuantizer(num_vq_embeddings, vq_embed_dim=latent_channels, legacy=False, beta=0.25)
# Decoder blocks
up_blocks = [nn.Sequential(nn.Conv2d(latent_channels, c_levels[-1], kernel_size=1))]
for i in range(levels):
for j in range(bottleneck_blocks if i == 0 else 1):
block = MixingResidualBlock(c_levels[levels - 1 - i], c_levels[levels - 1 - i] * 4)
up_blocks.append(block)
if i < levels - 1:
up_blocks.append(
nn.ConvTranspose2d(
c_levels[levels - 1 - i], c_levels[levels - 2 - i], kernel_size=4, stride=2, padding=1
)
)
self.up_blocks = nn.Sequential(*up_blocks)
self.out_block = nn.Sequential(
nn.Conv2d(c_levels[0], out_channels * up_down_scale_factor**2, kernel_size=1),
nn.PixelShuffle(up_down_scale_factor),
)
@apply_forward_hook
def encode(self, x: torch.FloatTensor, return_dict: bool = True) -> VQEncoderOutput:
h = self.in_block(x)
h = self.down_blocks(h)
if not return_dict:
return (h,)
return VQEncoderOutput(latents=h)
@apply_forward_hook
def decode(
self, h: torch.FloatTensor, force_not_quantize: bool = True, return_dict: bool = True
) -> Union[DecoderOutput, torch.FloatTensor]:
if not force_not_quantize:
quant, _, _ = self.vquantizer(h)
else:
quant = h
x = self.up_blocks(quant)
dec = self.out_block(x)
if not return_dict:
return (dec,)
return DecoderOutput(sample=dec)
def forward(self, sample: torch.FloatTensor, return_dict: bool = True) -> Union[DecoderOutput, torch.FloatTensor]:
r"""
Args:
sample (`torch.FloatTensor`): Input sample.
return_dict (`bool`, *optional*, defaults to `True`):
Whether or not to return a [`DecoderOutput`] instead of a plain tuple.
"""
x = sample
h = self.encode(x).latents
dec = self.decode(h).sample
if not return_dict:
return (dec,)
return DecoderOutput(sample=dec)
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