SDV VideoDecoder
This commit is contained in:
City
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import math
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import torch
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import numpy as np
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from torch import nn
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from typing import Callable, Iterable, Union, Optional
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from einops import rearrange, repeat
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from comfy import model_management
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from .kl import (
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Encoder, Decoder, Upsample, Normalize,
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AttnBlock, ResnetBlock, #MemoryEfficientAttnBlock,
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DiagonalGaussianDistribution, nonlinearity
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)
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class AutoencoderKL(nn.Module):
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def __init__(self, config):
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super().__init__()
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self.embed_dim = config["embed_dim"]
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self.encoder = Encoder(**config)
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self.decoder = VideoDecoder(**config)
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assert config["double_z"]
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# these aren't used here for some reason
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# self.quant_conv = torch.nn.Conv2d(2*config["z_channels"], 2*self.embed_dim, 1)
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# self.post_quant_conv = torch.nn.Conv2d(self.embed_dim, config["z_channels"], 1)
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def encode(self, x):
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## batched
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# n_samples = x.shape[0]
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# n_rounds = math.ceil(x.shape[0] / n_samples)
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# all_out = []
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# for n in range(n_rounds):
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# h = self.encoder(
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# x[n * n_samples : (n + 1) * n_samples]
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# )
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# moments = h # self.quant_conv(h)
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# posterior = DiagonalGaussianDistribution(moments)
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# all_out.append(posterior.sample())
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# z = torch.cat(all_out, dim=0)
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# return z
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## default
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h = self.encoder(x)
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moments = h # self.quant_conv(h)
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posterior = DiagonalGaussianDistribution(moments)
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return posterior.sample()
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def decode(self, z):
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## batched - seems the same as default?
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# n_samples = z.shape[0]
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# n_rounds = math.ceil(z.shape[0] / n_samples)
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# all_out = []
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# for n in range(n_rounds):
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# dec = self.decoder(
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# z[n * n_samples : (n + 1) * n_samples],
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# timesteps=len(z[n * n_samples : (n + 1) * n_samples]),
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# )
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# all_out.append(dec)
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# out = torch.cat(all_out, dim=0)
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## default
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out = self.decoder(
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z, timesteps=len(z)
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)
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return out
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def forward(self, input, sample_posterior=True):
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posterior = self.encode(input)
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if sample_posterior:
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z = posterior.sample()
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else:
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z = posterior.mode()
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dec = self.decode(z)
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return dec, posterior
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class VideoDecoder(nn.Module):
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available_time_modes = ["all", "conv-only", "attn-only"]
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def __init__(
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self, *, ch, out_ch, ch_mult=(1,2,4,8), num_res_blocks,
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attn_resolutions, dropout=0.0, resamp_with_conv=True, in_channels,
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resolution, z_channels, give_pre_end=False, tanh_out=False, use_linear_attn=False,
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attn_type="vanilla",
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video_kernel_size: Union[int, list] = 3, alpha: float = 0.0, merge_strategy: str = "learned", time_mode: str = "conv-only",
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**ignorekwargs
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):
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super().__init__()
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if use_linear_attn: attn_type = "linear"
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self.ch = ch
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self.temb_ch = 0
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self.num_resolutions = len(ch_mult)
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self.num_res_blocks = num_res_blocks
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self.resolution = resolution
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self.in_channels = in_channels
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self.give_pre_end = give_pre_end
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self.tanh_out = tanh_out
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self.video_kernel_size = video_kernel_size
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self.alpha = alpha
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self.merge_strategy = merge_strategy
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self.time_mode = time_mode
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assert (
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self.time_mode in self.available_time_modes
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), f"time_mode parameter has to be in {self.available_time_modes}"
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# compute in_ch_mult, block_in and curr_res at lowest res
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in_ch_mult = (1,)+tuple(ch_mult)
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block_in = ch*ch_mult[self.num_resolutions-1]
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curr_res = resolution // 2**(self.num_resolutions-1)
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self.z_shape = (1,z_channels,curr_res,curr_res)
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print("Working with z of shape {} = {} dimensions.".format(
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self.z_shape, np.prod(self.z_shape)))
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# z to block_in
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self.conv_in = torch.nn.Conv2d(
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z_channels,
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block_in,
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kernel_size=3,
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stride=1,
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padding=1
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)
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# middle
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self.mid = nn.Module()
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self.mid.block_1 = VideoResBlock(
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in_channels=block_in,
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out_channels=block_in,
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temb_channels=self.temb_ch,
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dropout=dropout,
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video_kernel_size=self.video_kernel_size,
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alpha=self.alpha,
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merge_strategy=self.merge_strategy,
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)
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self.mid.attn_1 = make_time_attn(
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block_in,
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attn_type=attn_type,
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alpha=self.alpha,
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merge_strategy=self.merge_strategy,
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)
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self.mid.block_2 = VideoResBlock(
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in_channels=block_in,
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out_channels=block_in,
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temb_channels=self.temb_ch,
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dropout=dropout,
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video_kernel_size=self.video_kernel_size,
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alpha=self.alpha,
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merge_strategy=self.merge_strategy,
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)
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# upsampling
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self.up = nn.ModuleList()
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for i_level in reversed(range(self.num_resolutions)):
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block = nn.ModuleList()
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attn = nn.ModuleList()
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block_out = ch*ch_mult[i_level]
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for i_block in range(self.num_res_blocks+1):
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block.append(VideoResBlock(
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in_channels=block_in,
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out_channels=block_out,
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temb_channels=self.temb_ch,
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dropout=dropout,
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video_kernel_size=self.video_kernel_size,
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alpha=self.alpha,
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merge_strategy=self.merge_strategy,
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))
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block_in = block_out
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if curr_res in attn_resolutions:
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attn.append(make_time_attn(
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block_in,
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attn_type=attn_type,
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alpha=self.alpha,
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merge_strategy=self.merge_strategy,
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))
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up = nn.Module()
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up.block = block
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up.attn = attn
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if i_level != 0:
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up.upsample = Upsample(block_in, resamp_with_conv)
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curr_res = curr_res * 2
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self.up.insert(0, up) # prepend to get consistent order
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# end
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self.norm_out = Normalize(block_in)
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self.conv_out = AE3DConv(
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in_channels = block_in,
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out_channels = out_ch,
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video_kernel_size=self.video_kernel_size,
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kernel_size=3,
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stride=1,
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padding=1,
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)
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def get_last_layer(self, skip_time_mix=False, **kwargs):
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if self.time_mode == "attn-only":
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raise NotImplementedError("TODO")
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else:
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return (
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self.conv_out.time_mix_conv.weight
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if not skip_time_mix
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else self.conv_out.weight
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)
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def forward(self, z, **kwargs):
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#assert z.shape[1:] == self.z_shape[1:]
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self.last_z_shape = z.shape
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# timestep embedding
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temb = None
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# z to block_in
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h = self.conv_in(z)
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# middle
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h = self.mid.block_1(h, temb, **kwargs)
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h = self.mid.attn_1(h, **kwargs)
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h = self.mid.block_2(h, temb, **kwargs)
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# upsampling
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for i_level in reversed(range(self.num_resolutions)):
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for i_block in range(self.num_res_blocks+1):
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h = self.up[i_level].block[i_block](h, temb, **kwargs)
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if len(self.up[i_level].attn) > 0:
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h = self.up[i_level].attn[i_block](h, **kwargs)
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if i_level != 0:
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h = self.up[i_level].upsample(h)
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# end
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if self.give_pre_end:
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return h
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h = self.norm_out(h)
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h = nonlinearity(h)
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h = self.conv_out(h, **kwargs)
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if self.tanh_out:
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h = torch.tanh(h)
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return h
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class CrossAttention(nn.Module):
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def __init__(
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self,
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query_dim,
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context_dim=None,
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heads=8,
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dim_head=64,
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dropout=0.0,
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backend=None,
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):
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super().__init__()
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inner_dim = dim_head * heads
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context_dim = context_dim or query_dim
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self.scale = dim_head**-0.5
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self.heads = heads
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self.to_q = nn.Linear(query_dim, inner_dim, bias=False)
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self.to_k = nn.Linear(context_dim, inner_dim, bias=False)
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self.to_v = nn.Linear(context_dim, inner_dim, bias=False)
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self.to_out = nn.Sequential(
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nn.Linear(inner_dim, query_dim), nn.Dropout(dropout)
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)
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self.backend = backend
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def forward(
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self,
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x,
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context=None,
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mask=None,
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additional_tokens=None,
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n_times_crossframe_attn_in_self=0,
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):
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h = self.heads
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if additional_tokens is not None:
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# get the number of masked tokens at the beginning of the output sequence
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n_tokens_to_mask = additional_tokens.shape[1]
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# add additional token
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x = torch.cat([additional_tokens, x], dim=1)
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q = self.to_q(x)
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context = context or x
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k = self.to_k(context)
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v = self.to_v(context)
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if n_times_crossframe_attn_in_self:
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# reprogramming cross-frame attention as in https://arxiv.org/abs/2303.13439
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assert x.shape[0] % n_times_crossframe_attn_in_self == 0
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n_cp = x.shape[0] // n_times_crossframe_attn_in_self
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k = repeat(
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k[::n_times_crossframe_attn_in_self], "b ... -> (b n) ...", n=n_cp
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)
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v = repeat(
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v[::n_times_crossframe_attn_in_self], "b ... -> (b n) ...", n=n_cp
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)
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q, k, v = map(lambda t: rearrange(t, "b n (h d) -> b h n d", h=h), (q, k, v))
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## old
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"""
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sim = einsum('b i d, b j d -> b i j', q, k) * self.scale
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del q, k
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if exists(mask):
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mask = rearrange(mask, 'b ... -> b (...)')
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max_neg_value = -torch.finfo(sim.dtype).max
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mask = repeat(mask, 'b j -> (b h) () j', h=h)
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sim.masked_fill_(~mask, max_neg_value)
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# some quote about attention, that I just about had enough of
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sim = sim.softmax(dim=-1)
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out = einsum('b i j, b j d -> b i d', sim, v)
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"""
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## new
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with sdp_kernel(**BACKEND_MAP[self.backend]):
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# print("dispatching into backend", self.backend, "q/k/v shape: ", q.shape, k.shape, v.shape)
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out = F.scaled_dot_product_attention(
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q, k, v, attn_mask=mask
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) # scale is dim_head ** -0.5 per default
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del q, k, v
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out = rearrange(out, "b h n d -> b n (h d)", h=h)
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if additional_tokens is not None:
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# remove additional token
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out = out[:, n_tokens_to_mask:]
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return self.to_out(out)
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class VideoBlock(AttnBlock):
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def __init__(
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self, in_channels: int, alpha: float = 0, merge_strategy: str = "learned"
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):
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super().__init__(in_channels)
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# no context, single headed, as in base class
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self.time_mix_block = VideoTransformerBlock(
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dim=in_channels,
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n_heads=1,
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d_head=in_channels,
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checkpoint=False,
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ff_in=True,
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attn_mode="softmax",
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)
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time_embed_dim = self.in_channels * 4
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self.video_time_embed = torch.nn.Sequential(
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torch.nn.Linear(self.in_channels, time_embed_dim),
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torch.nn.SiLU(),
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torch.nn.Linear(time_embed_dim, self.in_channels),
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)
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self.merge_strategy = merge_strategy
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if self.merge_strategy == "fixed":
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self.register_buffer("mix_factor", torch.Tensor([alpha]))
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elif self.merge_strategy == "learned":
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self.register_parameter(
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"mix_factor", torch.nn.Parameter(torch.Tensor([alpha]))
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)
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else:
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raise ValueError(f"unknown merge strategy {self.merge_strategy}")
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def forward(self, x, timesteps, skip_video=False):
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if skip_video:
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return super().forward(x)
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x_in = x
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x = self.attention(x)
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h, w = x.shape[2:]
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x = rearrange(x, "b c h w -> b (h w) c")
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x_mix = x
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num_frames = torch.arange(timesteps, device=x.device)
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num_frames = repeat(num_frames, "t -> b t", b=x.shape[0] // timesteps)
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num_frames = rearrange(num_frames, "b t -> (b t)")
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t_emb = timestep_embedding(num_frames, self.in_channels, repeat_only=False)
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emb = self.video_time_embed(t_emb) # b, n_channels
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emb = emb[:, None, :]
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x_mix = x_mix + emb
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alpha = self.get_alpha()
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x_mix = self.time_mix_block(x_mix, timesteps=timesteps)
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x = alpha * x + (1.0 - alpha) * x_mix # alpha merge
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x = rearrange(x, "b (h w) c -> b c h w", h=h, w=w)
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x = self.proj_out(x)
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return x_in + x
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def attention(self, h_: torch.Tensor) -> torch.Tensor:
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h_ = self.norm(h_)
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q = self.q(h_)
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k = self.k(h_)
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v = self.v(h_)
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b, c, h, w = q.shape
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q, k, v = map(
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lambda x: rearrange(x, "b c h w -> b 1 (h w) c").contiguous(), (q, k, v)
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)
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h_ = torch.nn.functional.scaled_dot_product_attention(
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q, k, v
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) # scale is dim ** -0.5 per default
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# compute attention
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return rearrange(h_, "b 1 (h w) c -> b c h w", h=h, w=w, c=c, b=b)
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def forward(self, x, **kwargs):
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h_ = x
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h_ = self.attention(h_)
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h_ = self.proj_out(h_)
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return x + h_
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def get_alpha(
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self,
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):
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if self.merge_strategy == "fixed":
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return self.mix_factor
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elif self.merge_strategy == "learned":
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return torch.sigmoid(self.mix_factor)
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else:
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raise NotImplementedError(f"unknown merge strategy {self.merge_strategy}")
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class VideoTransformerBlock(nn.Module):
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ATTENTION_MODES = {
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"softmax": CrossAttention,
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# "softmax-xformers": MemoryEfficientCrossAttention,
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}
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def __init__(
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self,
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dim,
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n_heads,
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d_head,
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dropout=0.0,
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context_dim=None,
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gated_ff=True,
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checkpoint=True,
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timesteps=None,
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ff_in=False,
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inner_dim=None,
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attn_mode="softmax",
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disable_self_attn=False,
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disable_temporal_crossattention=False,
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switch_temporal_ca_to_sa=False,
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):
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super().__init__()
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attn_cls = self.ATTENTION_MODES.get(attn_mode, "softmax")
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self.ff_in = ff_in or inner_dim is not None
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if inner_dim is None:
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inner_dim = dim
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assert int(n_heads * d_head) == inner_dim
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self.is_res = inner_dim == dim
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if self.ff_in:
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self.norm_in = nn.LayerNorm(dim)
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self.ff_in = FeedForward(
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dim, dim_out=inner_dim, dropout=dropout, glu=gated_ff
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)
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self.timesteps = timesteps
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self.disable_self_attn = disable_self_attn
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if self.disable_self_attn:
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self.attn1 = attn_cls(
|
||||
query_dim=inner_dim,
|
||||
heads=n_heads,
|
||||
dim_head=d_head,
|
||||
context_dim=context_dim,
|
||||
dropout=dropout,
|
||||
) # is a cross-attention
|
||||
else:
|
||||
self.attn1 = attn_cls(
|
||||
query_dim=inner_dim, heads=n_heads, dim_head=d_head, dropout=dropout
|
||||
) # is a self-attention
|
||||
|
||||
self.ff = FeedForward(inner_dim, dim_out=dim, dropout=dropout, glu=gated_ff)
|
||||
|
||||
if disable_temporal_crossattention:
|
||||
if switch_temporal_ca_to_sa:
|
||||
raise ValueError
|
||||
else:
|
||||
self.attn2 = None
|
||||
else:
|
||||
self.norm2 = nn.LayerNorm(inner_dim)
|
||||
if switch_temporal_ca_to_sa:
|
||||
self.attn2 = attn_cls(
|
||||
query_dim=inner_dim, heads=n_heads, dim_head=d_head, dropout=dropout
|
||||
) # is a self-attention
|
||||
else:
|
||||
self.attn2 = attn_cls(
|
||||
query_dim=inner_dim,
|
||||
context_dim=context_dim,
|
||||
heads=n_heads,
|
||||
dim_head=d_head,
|
||||
dropout=dropout,
|
||||
) # is self-attn if context is none
|
||||
|
||||
self.norm1 = nn.LayerNorm(inner_dim)
|
||||
self.norm3 = nn.LayerNorm(inner_dim)
|
||||
self.switch_temporal_ca_to_sa = switch_temporal_ca_to_sa
|
||||
|
||||
self.checkpoint = checkpoint
|
||||
if self.checkpoint:
|
||||
print(f"{self.__class__.__name__} is using checkpointing")
|
||||
|
||||
def forward(
|
||||
self, x: torch.Tensor, context: torch.Tensor = None, timesteps: int = None
|
||||
) -> torch.Tensor:
|
||||
if self.checkpoint:
|
||||
return checkpoint(self._forward, x, context, timesteps)
|
||||
else:
|
||||
return self._forward(x, context, timesteps=timesteps)
|
||||
|
||||
def _forward(self, x, context=None, timesteps=None):
|
||||
assert self.timesteps or timesteps
|
||||
assert not (self.timesteps and timesteps) or self.timesteps == timesteps
|
||||
timesteps = self.timesteps or timesteps
|
||||
B, S, C = x.shape
|
||||
x = rearrange(x, "(b t) s c -> (b s) t c", t=timesteps)
|
||||
|
||||
if self.ff_in:
|
||||
x_skip = x
|
||||
x = self.ff_in(self.norm_in(x))
|
||||
if self.is_res:
|
||||
x += x_skip
|
||||
|
||||
if self.disable_self_attn:
|
||||
x = self.attn1(self.norm1(x), context=context) + x
|
||||
else:
|
||||
x = self.attn1(self.norm1(x)) + x
|
||||
|
||||
if self.attn2 is not None:
|
||||
if self.switch_temporal_ca_to_sa:
|
||||
x = self.attn2(self.norm2(x)) + x
|
||||
else:
|
||||
x = self.attn2(self.norm2(x), context=context) + x
|
||||
x_skip = x
|
||||
x = self.ff(self.norm3(x))
|
||||
if self.is_res:
|
||||
x += x_skip
|
||||
|
||||
x = rearrange(
|
||||
x, "(b s) t c -> (b t) s c", s=S, b=B // timesteps, c=C, t=timesteps
|
||||
)
|
||||
return x
|
||||
|
||||
def get_last_layer(self):
|
||||
return self.ff.net[-1].weight
|
||||
|
||||
class ResBlock(nn.Module):
|
||||
"""
|
||||
A residual block that can optionally change the number of channels.
|
||||
:param channels: the number of input channels.
|
||||
:param emb_channels: the number of timestep embedding channels.
|
||||
:param dropout: the rate of dropout.
|
||||
:param out_channels: if specified, the number of out channels.
|
||||
:param use_conv: if True and out_channels is specified, use a spatial
|
||||
convolution instead of a smaller 1x1 convolution to change the
|
||||
channels in the skip connection.
|
||||
:param dims: determines if the signal is 1D, 2D, or 3D.
|
||||
:param use_checkpoint: if True, use gradient checkpointing on this module.
|
||||
:param up: if True, use this block for upsampling.
|
||||
:param down: if True, use this block for downsampling.
|
||||
"""
|
||||
|
||||
def __init__(
|
||||
self,
|
||||
channels: int,
|
||||
emb_channels: int,
|
||||
dropout: float,
|
||||
out_channels: Optional[int] = None,
|
||||
use_conv: bool = False,
|
||||
use_scale_shift_norm: bool = False,
|
||||
dims: int = 2,
|
||||
use_checkpoint: bool = False,
|
||||
up: bool = False,
|
||||
down: bool = False,
|
||||
kernel_size: int = 3,
|
||||
exchange_temb_dims: bool = False,
|
||||
skip_t_emb: bool = False,
|
||||
):
|
||||
super().__init__()
|
||||
self.channels = channels
|
||||
self.emb_channels = emb_channels
|
||||
self.dropout = dropout
|
||||
self.out_channels = out_channels or channels
|
||||
self.use_conv = use_conv
|
||||
self.use_checkpoint = use_checkpoint
|
||||
self.use_scale_shift_norm = use_scale_shift_norm
|
||||
self.exchange_temb_dims = exchange_temb_dims
|
||||
|
||||
if isinstance(kernel_size, Iterable):
|
||||
padding = [k // 2 for k in kernel_size]
|
||||
else:
|
||||
padding = kernel_size // 2
|
||||
|
||||
self.in_layers = nn.Sequential(
|
||||
normalization(channels),
|
||||
nn.SiLU(),
|
||||
conv_nd(dims, channels, self.out_channels, kernel_size, padding=padding),
|
||||
)
|
||||
|
||||
self.updown = up or down
|
||||
|
||||
if up:
|
||||
self.h_upd = Upsample(channels, False, dims)
|
||||
self.x_upd = Upsample(channels, False, dims)
|
||||
elif down:
|
||||
self.h_upd = Downsample(channels, False, dims)
|
||||
self.x_upd = Downsample(channels, False, dims)
|
||||
else:
|
||||
self.h_upd = self.x_upd = nn.Identity()
|
||||
|
||||
self.skip_t_emb = skip_t_emb
|
||||
self.emb_out_channels = (
|
||||
2 * self.out_channels if use_scale_shift_norm else self.out_channels
|
||||
)
|
||||
if self.skip_t_emb:
|
||||
print(f"Skipping timestep embedding in {self.__class__.__name__}")
|
||||
assert not self.use_scale_shift_norm
|
||||
self.emb_layers = None
|
||||
self.exchange_temb_dims = False
|
||||
else:
|
||||
self.emb_layers = nn.Sequential(
|
||||
nn.SiLU(),
|
||||
linear(
|
||||
emb_channels,
|
||||
self.emb_out_channels,
|
||||
),
|
||||
)
|
||||
|
||||
self.out_layers = nn.Sequential(
|
||||
normalization(self.out_channels),
|
||||
nn.SiLU(),
|
||||
nn.Dropout(p=dropout),
|
||||
zero_module(
|
||||
conv_nd(
|
||||
dims,
|
||||
self.out_channels,
|
||||
self.out_channels,
|
||||
kernel_size,
|
||||
padding=padding,
|
||||
)
|
||||
),
|
||||
)
|
||||
|
||||
if self.out_channels == channels:
|
||||
self.skip_connection = nn.Identity()
|
||||
elif use_conv:
|
||||
self.skip_connection = conv_nd(
|
||||
dims, channels, self.out_channels, kernel_size, padding=padding
|
||||
)
|
||||
else:
|
||||
self.skip_connection = conv_nd(dims, channels, self.out_channels, 1)
|
||||
|
||||
def forward(self, x: torch.Tensor, emb: torch.Tensor) -> torch.Tensor:
|
||||
"""
|
||||
Apply the block to a Tensor, conditioned on a timestep embedding.
|
||||
:param x: an [N x C x ...] Tensor of features.
|
||||
:param emb: an [N x emb_channels] Tensor of timestep embeddings.
|
||||
:return: an [N x C x ...] Tensor of outputs.
|
||||
"""
|
||||
if self.use_checkpoint:
|
||||
return checkpoint(self._forward, x, emb)
|
||||
else:
|
||||
return self._forward(x, emb)
|
||||
|
||||
def _forward(self, x: torch.Tensor, emb: torch.Tensor) -> torch.Tensor:
|
||||
if self.updown:
|
||||
in_rest, in_conv = self.in_layers[:-1], self.in_layers[-1]
|
||||
h = in_rest(x)
|
||||
h = self.h_upd(h)
|
||||
x = self.x_upd(x)
|
||||
h = in_conv(h)
|
||||
else:
|
||||
h = self.in_layers(x)
|
||||
|
||||
if self.skip_t_emb:
|
||||
emb_out = torch.zeros_like(h)
|
||||
else:
|
||||
emb_out = self.emb_layers(emb).type(h.dtype)
|
||||
while len(emb_out.shape) < len(h.shape):
|
||||
emb_out = emb_out[..., None]
|
||||
if self.use_scale_shift_norm:
|
||||
out_norm, out_rest = self.out_layers[0], self.out_layers[1:]
|
||||
scale, shift = torch.chunk(emb_out, 2, dim=1)
|
||||
h = out_norm(h) * (1 + scale) + shift
|
||||
h = out_rest(h)
|
||||
else:
|
||||
if self.exchange_temb_dims:
|
||||
emb_out = rearrange(emb_out, "b t c ... -> b c t ...")
|
||||
h = h + emb_out
|
||||
h = self.out_layers(h)
|
||||
return self.skip_connection(x) + h
|
||||
|
||||
class VideoResBlock(ResnetBlock):
|
||||
def __init__(
|
||||
self,
|
||||
out_channels,
|
||||
*args,
|
||||
dropout=0.0,
|
||||
video_kernel_size=3,
|
||||
alpha=0.0,
|
||||
merge_strategy="learned",
|
||||
**kwargs,
|
||||
):
|
||||
super().__init__(out_channels=out_channels, dropout=dropout, *args, **kwargs)
|
||||
if video_kernel_size is None:
|
||||
video_kernel_size = [3, 1, 1]
|
||||
self.time_stack = ResBlock(
|
||||
channels=out_channels,
|
||||
emb_channels=0,
|
||||
dropout=dropout,
|
||||
dims=3,
|
||||
use_scale_shift_norm=False,
|
||||
use_conv=False,
|
||||
up=False,
|
||||
down=False,
|
||||
kernel_size=video_kernel_size,
|
||||
use_checkpoint=False,
|
||||
skip_t_emb=True,
|
||||
)
|
||||
|
||||
self.merge_strategy = merge_strategy
|
||||
if self.merge_strategy == "fixed":
|
||||
self.register_buffer("mix_factor", torch.Tensor([alpha]))
|
||||
elif self.merge_strategy == "learned":
|
||||
self.register_parameter(
|
||||
"mix_factor", torch.nn.Parameter(torch.Tensor([alpha]))
|
||||
)
|
||||
else:
|
||||
raise ValueError(f"unknown merge strategy {self.merge_strategy}")
|
||||
|
||||
def get_alpha(self, bs):
|
||||
if self.merge_strategy == "fixed":
|
||||
return self.mix_factor
|
||||
elif self.merge_strategy == "learned":
|
||||
return torch.sigmoid(self.mix_factor)
|
||||
else:
|
||||
raise NotImplementedError()
|
||||
|
||||
def forward(self, x, temb, skip_video=False, timesteps=None):
|
||||
if timesteps is None:
|
||||
timesteps = self.timesteps
|
||||
|
||||
b, c, h, w = x.shape
|
||||
|
||||
x = super().forward(x, temb)
|
||||
|
||||
if not skip_video:
|
||||
x_mix = rearrange(x, "(b t) c h w -> b c t h w", t=timesteps)
|
||||
|
||||
x = rearrange(x, "(b t) c h w -> b c t h w", t=timesteps)
|
||||
|
||||
x = self.time_stack(x, temb)
|
||||
|
||||
alpha = self.get_alpha(bs=b // timesteps)
|
||||
x = alpha * x + (1.0 - alpha) * x_mix
|
||||
|
||||
x = rearrange(x, "b c t h w -> (b t) c h w")
|
||||
return x
|
||||
|
||||
class AE3DConv(torch.nn.Conv2d):
|
||||
def __init__(self, in_channels, out_channels, video_kernel_size=3, *args, **kwargs):
|
||||
super().__init__(in_channels, out_channels, *args, **kwargs)
|
||||
if isinstance(video_kernel_size, Iterable):
|
||||
padding = [int(k // 2) for k in video_kernel_size]
|
||||
else:
|
||||
padding = int(video_kernel_size // 2)
|
||||
|
||||
self.time_mix_conv = torch.nn.Conv3d(
|
||||
in_channels=out_channels,
|
||||
out_channels=out_channels,
|
||||
kernel_size=video_kernel_size,
|
||||
padding=padding,
|
||||
)
|
||||
|
||||
def forward(self, input, timesteps, skip_video=False):
|
||||
x = super().forward(input)
|
||||
if skip_video:
|
||||
return x
|
||||
x = rearrange(x, "(b t) c h w -> b c t h w", t=timesteps)
|
||||
x = self.time_mix_conv(x)
|
||||
return rearrange(x, "b c t h w -> (b t) c h w")
|
||||
|
||||
def make_time_attn(in_channels, attn_type="vanilla", attn_kwargs=None, alpha: float = 0, merge_strategy: str = "learned"):
|
||||
if attn_type == "vanilla":
|
||||
assert attn_kwargs is None
|
||||
return VideoBlock(
|
||||
in_channels,
|
||||
alpha=alpha,
|
||||
merge_strategy=merge_strategy,
|
||||
)
|
||||
# lazy to add the xformers code
|
||||
else:
|
||||
return NotImplementedError()
|
||||
|
||||
def timestep_embedding(timesteps, dim, max_period=10000, repeat_only=False):
|
||||
"""
|
||||
Create sinusoidal timestep embeddings.
|
||||
:param timesteps: a 1-D Tensor of N indices, one per batch element.
|
||||
These may be fractional.
|
||||
:param dim: the dimension of the output.
|
||||
:param max_period: controls the minimum frequency of the embeddings.
|
||||
:return: an [N x dim] Tensor of positional embeddings.
|
||||
"""
|
||||
if not repeat_only:
|
||||
half = dim // 2
|
||||
freqs = torch.exp(
|
||||
-math.log(max_period)
|
||||
* torch.arange(start=0, end=half, dtype=torch.float32)
|
||||
/ half
|
||||
).to(device=timesteps.device)
|
||||
args = timesteps[:, None].float() * freqs[None]
|
||||
embedding = torch.cat([torch.cos(args), torch.sin(args)], dim=-1)
|
||||
if dim % 2:
|
||||
embedding = torch.cat(
|
||||
[embedding, torch.zeros_like(embedding[:, :1])], dim=-1
|
||||
)
|
||||
else:
|
||||
embedding = repeat(timesteps, "b -> b d", d=dim)
|
||||
return embedding
|
||||
|
||||
def normalization(channels):
|
||||
"""
|
||||
Make a standard normalization layer.
|
||||
:param channels: number of input channels.
|
||||
:return: an nn.Module for normalization.
|
||||
"""
|
||||
return GroupNorm32(32, channels)
|
||||
|
||||
class SiLU(nn.Module):
|
||||
def forward(self, x):
|
||||
return x * torch.sigmoid(x)
|
||||
|
||||
class GroupNorm32(nn.GroupNorm):
|
||||
def forward(self, x):
|
||||
return super().forward(x.float()).type(x.dtype)
|
||||
|
||||
def conv_nd(dims, *args, **kwargs):
|
||||
"""
|
||||
Create a 1D, 2D, or 3D convolution module.
|
||||
"""
|
||||
if dims == 1:
|
||||
return nn.Conv1d(*args, **kwargs)
|
||||
elif dims == 2:
|
||||
return nn.Conv2d(*args, **kwargs)
|
||||
elif dims == 3:
|
||||
return nn.Conv3d(*args, **kwargs)
|
||||
raise ValueError(f"unsupported dimensions: {dims}")
|
||||
|
||||
def zero_module(module):
|
||||
"""
|
||||
Zero out the parameters of a module and return it.
|
||||
"""
|
||||
for p in module.parameters():
|
||||
p.detach().zero_()
|
||||
return module
|
||||
|
||||
# feedforward
|
||||
class GEGLU(nn.Module):
|
||||
def __init__(self, dim_in, dim_out):
|
||||
super().__init__()
|
||||
self.proj = nn.Linear(dim_in, dim_out * 2)
|
||||
|
||||
def forward(self, x):
|
||||
x, gate = self.proj(x).chunk(2, dim=-1)
|
||||
return x * nn.functional.gelu(gate)
|
||||
|
||||
class FeedForward(nn.Module):
|
||||
def __init__(self, dim, dim_out=None, mult=4, glu=False, dropout=0.0):
|
||||
super().__init__()
|
||||
inner_dim = int(dim * mult)
|
||||
dim_out = dim_out or dim
|
||||
project_in = (
|
||||
nn.Sequential(nn.Linear(dim, inner_dim), nn.GELU())
|
||||
if not glu
|
||||
else GEGLU(dim, inner_dim)
|
||||
)
|
||||
|
||||
self.net = nn.Sequential(
|
||||
project_in, nn.Dropout(dropout), nn.Linear(inner_dim, dim_out)
|
||||
)
|
||||
|
||||
def forward(self, x):
|
||||
return self.net(x)
|
||||
Reference in New Issue
Block a user