712 lines
22 KiB
Python
712 lines
22 KiB
Python
#original code from https://github.com/genmoai/models under apache 2.0 license
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#adapted to ComfyUI
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from typing import Callable, List, Optional, Tuple, Union
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from functools import partial
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import math
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import torch
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import torch.nn as nn
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import torch.nn.functional as F
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from einops import rearrange
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from comfy.ldm.modules.attention import optimized_attention
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import comfy.ops
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ops = comfy.ops.disable_weight_init
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# import mochi_preview.dit.joint_model.context_parallel as cp
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# from mochi_preview.vae.cp_conv import cp_pass_frames, gather_all_frames
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def cast_tuple(t, length=1):
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return t if isinstance(t, tuple) else ((t,) * length)
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class GroupNormSpatial(ops.GroupNorm):
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"""
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GroupNorm applied per-frame.
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"""
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def forward(self, x: torch.Tensor, *, chunk_size: int = 8):
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B, C, T, H, W = x.shape
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x = rearrange(x, "B C T H W -> (B T) C H W")
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# Run group norm in chunks.
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output = torch.empty_like(x)
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for b in range(0, B * T, chunk_size):
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output[b : b + chunk_size] = super().forward(x[b : b + chunk_size])
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return rearrange(output, "(B T) C H W -> B C T H W", B=B, T=T)
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class PConv3d(ops.Conv3d):
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def __init__(
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self,
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in_channels,
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out_channels,
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kernel_size: Union[int, Tuple[int, int, int]],
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stride: Union[int, Tuple[int, int, int]],
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causal: bool = True,
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context_parallel: bool = True,
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**kwargs,
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):
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self.causal = causal
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self.context_parallel = context_parallel
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kernel_size = cast_tuple(kernel_size, 3)
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stride = cast_tuple(stride, 3)
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height_pad = (kernel_size[1] - 1) // 2
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width_pad = (kernel_size[2] - 1) // 2
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super().__init__(
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in_channels=in_channels,
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out_channels=out_channels,
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kernel_size=kernel_size,
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stride=stride,
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dilation=(1, 1, 1),
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padding=(0, height_pad, width_pad),
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**kwargs,
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)
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def forward(self, x: torch.Tensor):
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# Compute padding amounts.
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context_size = self.kernel_size[0] - 1
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if self.causal:
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pad_front = context_size
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pad_back = 0
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else:
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pad_front = context_size // 2
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pad_back = context_size - pad_front
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# Apply padding.
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assert self.padding_mode == "replicate" # DEBUG
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mode = "constant" if self.padding_mode == "zeros" else self.padding_mode
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x = F.pad(x, (0, 0, 0, 0, pad_front, pad_back), mode=mode)
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return super().forward(x)
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class Conv1x1(ops.Linear):
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"""*1x1 Conv implemented with a linear layer."""
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def __init__(self, in_features: int, out_features: int, *args, **kwargs):
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super().__init__(in_features, out_features, *args, **kwargs)
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def forward(self, x: torch.Tensor):
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"""Forward pass.
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Args:
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x: Input tensor. Shape: [B, C, *] or [B, *, C].
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Returns:
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x: Output tensor. Shape: [B, C', *] or [B, *, C'].
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"""
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x = x.movedim(1, -1)
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x = super().forward(x)
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x = x.movedim(-1, 1)
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return x
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class DepthToSpaceTime(nn.Module):
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def __init__(
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self,
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temporal_expansion: int,
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spatial_expansion: int,
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):
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super().__init__()
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self.temporal_expansion = temporal_expansion
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self.spatial_expansion = spatial_expansion
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# When printed, this module should show the temporal and spatial expansion factors.
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def extra_repr(self):
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return f"texp={self.temporal_expansion}, sexp={self.spatial_expansion}"
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def forward(self, x: torch.Tensor):
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"""Forward pass.
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Args:
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x: Input tensor. Shape: [B, C, T, H, W].
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Returns:
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x: Rearranged tensor. Shape: [B, C/(st*s*s), T*st, H*s, W*s].
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"""
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x = rearrange(
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x,
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"B (C st sh sw) T H W -> B C (T st) (H sh) (W sw)",
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st=self.temporal_expansion,
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sh=self.spatial_expansion,
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sw=self.spatial_expansion,
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)
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# cp_rank, _ = cp.get_cp_rank_size()
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if self.temporal_expansion > 1: # and cp_rank == 0:
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# Drop the first self.temporal_expansion - 1 frames.
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# This is because we always want the 3x3x3 conv filter to only apply
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# to the first frame, and the first frame doesn't need to be repeated.
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assert all(x.shape)
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x = x[:, :, self.temporal_expansion - 1 :]
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assert all(x.shape)
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return x
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def norm_fn(
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in_channels: int,
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affine: bool = True,
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):
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return GroupNormSpatial(affine=affine, num_groups=32, num_channels=in_channels)
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class ResBlock(nn.Module):
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"""Residual block that preserves the spatial dimensions."""
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def __init__(
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self,
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channels: int,
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*,
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affine: bool = True,
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attn_block: Optional[nn.Module] = None,
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causal: bool = True,
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prune_bottleneck: bool = False,
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padding_mode: str,
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bias: bool = True,
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):
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super().__init__()
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self.channels = channels
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assert causal
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self.stack = nn.Sequential(
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norm_fn(channels, affine=affine),
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nn.SiLU(inplace=True),
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PConv3d(
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in_channels=channels,
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out_channels=channels // 2 if prune_bottleneck else channels,
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kernel_size=(3, 3, 3),
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stride=(1, 1, 1),
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padding_mode=padding_mode,
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bias=bias,
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causal=causal,
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),
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norm_fn(channels, affine=affine),
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nn.SiLU(inplace=True),
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PConv3d(
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in_channels=channels // 2 if prune_bottleneck else channels,
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out_channels=channels,
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kernel_size=(3, 3, 3),
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stride=(1, 1, 1),
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padding_mode=padding_mode,
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bias=bias,
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causal=causal,
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),
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)
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self.attn_block = attn_block if attn_block else nn.Identity()
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def forward(self, x: torch.Tensor):
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"""Forward pass.
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Args:
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x: Input tensor. Shape: [B, C, T, H, W].
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"""
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residual = x
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x = self.stack(x)
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x = x + residual
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del residual
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return self.attn_block(x)
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class Attention(nn.Module):
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def __init__(
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self,
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dim: int,
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head_dim: int = 32,
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qkv_bias: bool = False,
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out_bias: bool = True,
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qk_norm: bool = True,
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) -> None:
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super().__init__()
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self.head_dim = head_dim
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self.num_heads = dim // head_dim
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self.qk_norm = qk_norm
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self.qkv = nn.Linear(dim, 3 * dim, bias=qkv_bias)
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self.out = nn.Linear(dim, dim, bias=out_bias)
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def forward(
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self,
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x: torch.Tensor,
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) -> torch.Tensor:
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"""Compute temporal self-attention.
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Args:
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x: Input tensor. Shape: [B, C, T, H, W].
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chunk_size: Chunk size for large tensors.
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Returns:
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x: Output tensor. Shape: [B, C, T, H, W].
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"""
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B, _, T, H, W = x.shape
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if T == 1:
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# No attention for single frame.
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x = x.movedim(1, -1) # [B, C, T, H, W] -> [B, T, H, W, C]
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qkv = self.qkv(x)
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_, _, x = qkv.chunk(3, dim=-1) # Throw away queries and keys.
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x = self.out(x)
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return x.movedim(-1, 1) # [B, T, H, W, C] -> [B, C, T, H, W]
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# 1D temporal attention.
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x = rearrange(x, "B C t h w -> (B h w) t C")
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qkv = self.qkv(x)
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# Input: qkv with shape [B, t, 3 * num_heads * head_dim]
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# Output: x with shape [B, num_heads, t, head_dim]
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q, k, v = qkv.view(qkv.shape[0], qkv.shape[1], 3, self.num_heads, self.head_dim).transpose(1, 3).unbind(2)
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if self.qk_norm:
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q = F.normalize(q, p=2, dim=-1)
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k = F.normalize(k, p=2, dim=-1)
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x = optimized_attention(q, k, v, self.num_heads, skip_reshape=True)
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assert x.size(0) == q.size(0)
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x = self.out(x)
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x = rearrange(x, "(B h w) t C -> B C t h w", B=B, h=H, w=W)
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return x
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class AttentionBlock(nn.Module):
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def __init__(
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self,
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dim: int,
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**attn_kwargs,
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) -> None:
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super().__init__()
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self.norm = norm_fn(dim)
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self.attn = Attention(dim, **attn_kwargs)
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def forward(self, x: torch.Tensor) -> torch.Tensor:
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return x + self.attn(self.norm(x))
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class CausalUpsampleBlock(nn.Module):
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def __init__(
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self,
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in_channels: int,
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out_channels: int,
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num_res_blocks: int,
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*,
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temporal_expansion: int = 2,
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spatial_expansion: int = 2,
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**block_kwargs,
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):
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super().__init__()
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blocks = []
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for _ in range(num_res_blocks):
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blocks.append(block_fn(in_channels, **block_kwargs))
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self.blocks = nn.Sequential(*blocks)
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self.temporal_expansion = temporal_expansion
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self.spatial_expansion = spatial_expansion
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# Change channels in the final convolution layer.
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self.proj = Conv1x1(
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in_channels,
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out_channels * temporal_expansion * (spatial_expansion**2),
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)
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self.d2st = DepthToSpaceTime(
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temporal_expansion=temporal_expansion, spatial_expansion=spatial_expansion
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)
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def forward(self, x):
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x = self.blocks(x)
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x = self.proj(x)
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x = self.d2st(x)
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return x
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def block_fn(channels, *, affine: bool = True, has_attention: bool = False, **block_kwargs):
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attn_block = AttentionBlock(channels) if has_attention else None
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return ResBlock(channels, affine=affine, attn_block=attn_block, **block_kwargs)
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class DownsampleBlock(nn.Module):
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def __init__(
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self,
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in_channels: int,
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out_channels: int,
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num_res_blocks,
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*,
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temporal_reduction=2,
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spatial_reduction=2,
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**block_kwargs,
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):
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"""
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Downsample block for the VAE encoder.
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Args:
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in_channels: Number of input channels.
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out_channels: Number of output channels.
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num_res_blocks: Number of residual blocks.
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temporal_reduction: Temporal reduction factor.
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spatial_reduction: Spatial reduction factor.
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"""
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super().__init__()
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layers = []
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# Change the channel count in the strided convolution.
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# This lets the ResBlock have uniform channel count,
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# as in ConvNeXt.
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assert in_channels != out_channels
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layers.append(
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PConv3d(
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in_channels=in_channels,
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out_channels=out_channels,
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kernel_size=(temporal_reduction, spatial_reduction, spatial_reduction),
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stride=(temporal_reduction, spatial_reduction, spatial_reduction),
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# First layer in each block always uses replicate padding
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padding_mode="replicate",
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bias=block_kwargs["bias"],
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)
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)
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for _ in range(num_res_blocks):
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layers.append(block_fn(out_channels, **block_kwargs))
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self.layers = nn.Sequential(*layers)
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def forward(self, x):
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return self.layers(x)
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def add_fourier_features(inputs: torch.Tensor, start=6, stop=8, step=1):
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num_freqs = (stop - start) // step
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assert inputs.ndim == 5
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C = inputs.size(1)
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# Create Base 2 Fourier features.
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freqs = torch.arange(start, stop, step, dtype=inputs.dtype, device=inputs.device)
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assert num_freqs == len(freqs)
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w = torch.pow(2.0, freqs) * (2 * torch.pi) # [num_freqs]
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C = inputs.shape[1]
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w = w.repeat(C)[None, :, None, None, None] # [1, C * num_freqs, 1, 1, 1]
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# Interleaved repeat of input channels to match w.
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h = inputs.repeat_interleave(num_freqs, dim=1) # [B, C * num_freqs, T, H, W]
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# Scale channels by frequency.
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h = w * h
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return torch.cat(
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[
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inputs,
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torch.sin(h),
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torch.cos(h),
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],
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dim=1,
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)
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class FourierFeatures(nn.Module):
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def __init__(self, start: int = 6, stop: int = 8, step: int = 1):
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super().__init__()
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self.start = start
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self.stop = stop
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self.step = step
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def forward(self, inputs):
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"""Add Fourier features to inputs.
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Args:
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inputs: Input tensor. Shape: [B, C, T, H, W]
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Returns:
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h: Output tensor. Shape: [B, (1 + 2 * num_freqs) * C, T, H, W]
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"""
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return add_fourier_features(inputs, self.start, self.stop, self.step)
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class Decoder(nn.Module):
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def __init__(
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self,
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*,
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out_channels: int = 3,
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latent_dim: int,
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base_channels: int,
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channel_multipliers: List[int],
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num_res_blocks: List[int],
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temporal_expansions: Optional[List[int]] = None,
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spatial_expansions: Optional[List[int]] = None,
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has_attention: List[bool],
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output_norm: bool = True,
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nonlinearity: str = "silu",
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output_nonlinearity: str = "silu",
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causal: bool = True,
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**block_kwargs,
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):
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super().__init__()
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self.input_channels = latent_dim
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self.base_channels = base_channels
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self.channel_multipliers = channel_multipliers
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self.num_res_blocks = num_res_blocks
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self.output_nonlinearity = output_nonlinearity
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assert nonlinearity == "silu"
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assert causal
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ch = [mult * base_channels for mult in channel_multipliers]
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self.num_up_blocks = len(ch) - 1
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assert len(num_res_blocks) == self.num_up_blocks + 2
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blocks = []
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first_block = [
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ops.Conv3d(latent_dim, ch[-1], kernel_size=(1, 1, 1))
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] # Input layer.
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# First set of blocks preserve channel count.
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for _ in range(num_res_blocks[-1]):
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first_block.append(
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block_fn(
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ch[-1],
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has_attention=has_attention[-1],
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causal=causal,
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**block_kwargs,
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)
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)
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blocks.append(nn.Sequential(*first_block))
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assert len(temporal_expansions) == len(spatial_expansions) == self.num_up_blocks
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assert len(num_res_blocks) == len(has_attention) == self.num_up_blocks + 2
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upsample_block_fn = CausalUpsampleBlock
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for i in range(self.num_up_blocks):
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block = upsample_block_fn(
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ch[-i - 1],
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ch[-i - 2],
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num_res_blocks=num_res_blocks[-i - 2],
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has_attention=has_attention[-i - 2],
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temporal_expansion=temporal_expansions[-i - 1],
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spatial_expansion=spatial_expansions[-i - 1],
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causal=causal,
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**block_kwargs,
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)
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blocks.append(block)
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assert not output_norm
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# Last block. Preserve channel count.
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last_block = []
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for _ in range(num_res_blocks[0]):
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last_block.append(
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block_fn(
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ch[0], has_attention=has_attention[0], causal=causal, **block_kwargs
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)
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)
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blocks.append(nn.Sequential(*last_block))
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self.blocks = nn.ModuleList(blocks)
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self.output_proj = Conv1x1(ch[0], out_channels)
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def forward(self, x):
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"""Forward pass.
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Args:
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x: Latent tensor. Shape: [B, input_channels, t, h, w]. Scaled [-1, 1].
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Returns:
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x: Reconstructed video tensor. Shape: [B, C, T, H, W]. Scaled to [-1, 1].
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T + 1 = (t - 1) * 4.
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H = h * 16, W = w * 16.
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"""
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for block in self.blocks:
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x = block(x)
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if self.output_nonlinearity == "silu":
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x = F.silu(x, inplace=not self.training)
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else:
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assert (
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not self.output_nonlinearity
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) # StyleGAN3 omits the to-RGB nonlinearity.
|
|
|
|
return self.output_proj(x).contiguous()
|
|
|
|
class LatentDistribution:
|
|
def __init__(self, mean: torch.Tensor, logvar: torch.Tensor):
|
|
"""Initialize latent distribution.
|
|
|
|
Args:
|
|
mean: Mean of the distribution. Shape: [B, C, T, H, W].
|
|
logvar: Logarithm of variance of the distribution. Shape: [B, C, T, H, W].
|
|
"""
|
|
assert mean.shape == logvar.shape
|
|
self.mean = mean
|
|
self.logvar = logvar
|
|
|
|
def sample(self, temperature=1.0, generator: torch.Generator = None, noise=None):
|
|
if temperature == 0.0:
|
|
return self.mean
|
|
|
|
if noise is None:
|
|
noise = torch.randn(self.mean.shape, device=self.mean.device, dtype=self.mean.dtype, generator=generator)
|
|
else:
|
|
assert noise.device == self.mean.device
|
|
noise = noise.to(self.mean.dtype)
|
|
|
|
if temperature != 1.0:
|
|
raise NotImplementedError(f"Temperature {temperature} is not supported.")
|
|
|
|
# Just Gaussian sample with no scaling of variance.
|
|
return noise * torch.exp(self.logvar * 0.5) + self.mean
|
|
|
|
def mode(self):
|
|
return self.mean
|
|
|
|
class Encoder(nn.Module):
|
|
def __init__(
|
|
self,
|
|
*,
|
|
in_channels: int,
|
|
base_channels: int,
|
|
channel_multipliers: List[int],
|
|
num_res_blocks: List[int],
|
|
latent_dim: int,
|
|
temporal_reductions: List[int],
|
|
spatial_reductions: List[int],
|
|
prune_bottlenecks: List[bool],
|
|
has_attentions: List[bool],
|
|
affine: bool = True,
|
|
bias: bool = True,
|
|
input_is_conv_1x1: bool = False,
|
|
padding_mode: str,
|
|
):
|
|
super().__init__()
|
|
self.temporal_reductions = temporal_reductions
|
|
self.spatial_reductions = spatial_reductions
|
|
self.base_channels = base_channels
|
|
self.channel_multipliers = channel_multipliers
|
|
self.num_res_blocks = num_res_blocks
|
|
self.latent_dim = latent_dim
|
|
|
|
self.fourier_features = FourierFeatures()
|
|
ch = [mult * base_channels for mult in channel_multipliers]
|
|
num_down_blocks = len(ch) - 1
|
|
assert len(num_res_blocks) == num_down_blocks + 2
|
|
|
|
layers = (
|
|
[ops.Conv3d(in_channels, ch[0], kernel_size=(1, 1, 1), bias=True)]
|
|
if not input_is_conv_1x1
|
|
else [Conv1x1(in_channels, ch[0])]
|
|
)
|
|
|
|
assert len(prune_bottlenecks) == num_down_blocks + 2
|
|
assert len(has_attentions) == num_down_blocks + 2
|
|
block = partial(block_fn, padding_mode=padding_mode, affine=affine, bias=bias)
|
|
|
|
for _ in range(num_res_blocks[0]):
|
|
layers.append(block(ch[0], has_attention=has_attentions[0], prune_bottleneck=prune_bottlenecks[0]))
|
|
prune_bottlenecks = prune_bottlenecks[1:]
|
|
has_attentions = has_attentions[1:]
|
|
|
|
assert len(temporal_reductions) == len(spatial_reductions) == len(ch) - 1
|
|
for i in range(num_down_blocks):
|
|
layer = DownsampleBlock(
|
|
ch[i],
|
|
ch[i + 1],
|
|
num_res_blocks=num_res_blocks[i + 1],
|
|
temporal_reduction=temporal_reductions[i],
|
|
spatial_reduction=spatial_reductions[i],
|
|
prune_bottleneck=prune_bottlenecks[i],
|
|
has_attention=has_attentions[i],
|
|
affine=affine,
|
|
bias=bias,
|
|
padding_mode=padding_mode,
|
|
)
|
|
|
|
layers.append(layer)
|
|
|
|
# Additional blocks.
|
|
for _ in range(num_res_blocks[-1]):
|
|
layers.append(block(ch[-1], has_attention=has_attentions[-1], prune_bottleneck=prune_bottlenecks[-1]))
|
|
|
|
self.layers = nn.Sequential(*layers)
|
|
|
|
# Output layers.
|
|
self.output_norm = norm_fn(ch[-1])
|
|
self.output_proj = Conv1x1(ch[-1], 2 * latent_dim, bias=False)
|
|
|
|
@property
|
|
def temporal_downsample(self):
|
|
return math.prod(self.temporal_reductions)
|
|
|
|
@property
|
|
def spatial_downsample(self):
|
|
return math.prod(self.spatial_reductions)
|
|
|
|
def forward(self, x) -> LatentDistribution:
|
|
"""Forward pass.
|
|
|
|
Args:
|
|
x: Input video tensor. Shape: [B, C, T, H, W]. Scaled to [-1, 1]
|
|
|
|
Returns:
|
|
means: Latent tensor. Shape: [B, latent_dim, t, h, w]. Scaled [-1, 1].
|
|
h = H // 8, w = W // 8, t - 1 = (T - 1) // 6
|
|
logvar: Shape: [B, latent_dim, t, h, w].
|
|
"""
|
|
assert x.ndim == 5, f"Expected 5D input, got {x.shape}"
|
|
x = self.fourier_features(x)
|
|
|
|
x = self.layers(x)
|
|
|
|
x = self.output_norm(x)
|
|
x = F.silu(x, inplace=True)
|
|
x = self.output_proj(x)
|
|
|
|
means, logvar = torch.chunk(x, 2, dim=1)
|
|
|
|
assert means.ndim == 5
|
|
assert logvar.shape == means.shape
|
|
assert means.size(1) == self.latent_dim
|
|
|
|
return LatentDistribution(means, logvar)
|
|
|
|
|
|
class VideoVAE(nn.Module):
|
|
def __init__(self):
|
|
super().__init__()
|
|
self.encoder = Encoder(
|
|
in_channels=15,
|
|
base_channels=64,
|
|
channel_multipliers=[1, 2, 4, 6],
|
|
num_res_blocks=[3, 3, 4, 6, 3],
|
|
latent_dim=12,
|
|
temporal_reductions=[1, 2, 3],
|
|
spatial_reductions=[2, 2, 2],
|
|
prune_bottlenecks=[False, False, False, False, False],
|
|
has_attentions=[False, True, True, True, True],
|
|
affine=True,
|
|
bias=True,
|
|
input_is_conv_1x1=True,
|
|
padding_mode="replicate"
|
|
)
|
|
self.decoder = Decoder(
|
|
out_channels=3,
|
|
base_channels=128,
|
|
channel_multipliers=[1, 2, 4, 6],
|
|
temporal_expansions=[1, 2, 3],
|
|
spatial_expansions=[2, 2, 2],
|
|
num_res_blocks=[3, 3, 4, 6, 3],
|
|
latent_dim=12,
|
|
has_attention=[False, False, False, False, False],
|
|
padding_mode="replicate",
|
|
output_norm=False,
|
|
nonlinearity="silu",
|
|
output_nonlinearity="silu",
|
|
causal=True,
|
|
)
|
|
|
|
def encode(self, x):
|
|
return self.encoder(x).mode()
|
|
|
|
def decode(self, x):
|
|
return self.decoder(x)
|