Mochi VAE encoder.

This commit is contained in:
comfyanonymous
2024-11-01 17:33:09 -04:00
parent cc9cf6d1bd
commit fabf449feb
3 changed files with 283 additions and 28 deletions

View File

@@ -2,12 +2,16 @@
#adapted to ComfyUI
from typing import Callable, List, Optional, Tuple, Union
from functools import partial
import math
import torch
import torch.nn as nn
import torch.nn.functional as F
from einops import rearrange
from comfy.ldm.modules.attention import optimized_attention
import comfy.ops
ops = comfy.ops.disable_weight_init
@@ -158,8 +162,10 @@ class ResBlock(nn.Module):
*,
affine: bool = True,
attn_block: Optional[nn.Module] = None,
padding_mode: str = "replicate",
causal: bool = True,
prune_bottleneck: bool = False,
padding_mode: str,
bias: bool = True,
):
super().__init__()
self.channels = channels
@@ -170,23 +176,23 @@ class ResBlock(nn.Module):
nn.SiLU(inplace=True),
PConv3d(
in_channels=channels,
out_channels=channels,
out_channels=channels // 2 if prune_bottleneck else channels,
kernel_size=(3, 3, 3),
stride=(1, 1, 1),
padding_mode=padding_mode,
bias=True,
# causal=causal,
bias=bias,
causal=causal,
),
norm_fn(channels, affine=affine),
nn.SiLU(inplace=True),
PConv3d(
in_channels=channels,
in_channels=channels // 2 if prune_bottleneck else channels,
out_channels=channels,
kernel_size=(3, 3, 3),
stride=(1, 1, 1),
padding_mode=padding_mode,
bias=True,
# causal=causal,
bias=bias,
causal=causal,
),
)
@@ -206,6 +212,81 @@ class ResBlock(nn.Module):
return self.attn_block(x)
class Attention(nn.Module):
def __init__(
self,
dim: int,
head_dim: int = 32,
qkv_bias: bool = False,
out_bias: bool = True,
qk_norm: bool = True,
) -> None:
super().__init__()
self.head_dim = head_dim
self.num_heads = dim // head_dim
self.qk_norm = qk_norm
self.qkv = nn.Linear(dim, 3 * dim, bias=qkv_bias)
self.out = nn.Linear(dim, dim, bias=out_bias)
def forward(
self,
x: torch.Tensor,
) -> torch.Tensor:
"""Compute temporal self-attention.
Args:
x: Input tensor. Shape: [B, C, T, H, W].
chunk_size: Chunk size for large tensors.
Returns:
x: Output tensor. Shape: [B, C, T, H, W].
"""
B, _, T, H, W = x.shape
if T == 1:
# No attention for single frame.
x = x.movedim(1, -1) # [B, C, T, H, W] -> [B, T, H, W, C]
qkv = self.qkv(x)
_, _, x = qkv.chunk(3, dim=-1) # Throw away queries and keys.
x = self.out(x)
return x.movedim(-1, 1) # [B, T, H, W, C] -> [B, C, T, H, W]
# 1D temporal attention.
x = rearrange(x, "B C t h w -> (B h w) t C")
qkv = self.qkv(x)
# Input: qkv with shape [B, t, 3 * num_heads * head_dim]
# Output: x with shape [B, num_heads, t, head_dim]
q, k, v = qkv.view(qkv.shape[0], qkv.shape[1], 3, self.num_heads, self.head_dim).transpose(1, 3).unbind(2)
if self.qk_norm:
q = F.normalize(q, p=2, dim=-1)
k = F.normalize(k, p=2, dim=-1)
x = optimized_attention(q, k, v, self.num_heads, skip_reshape=True)
assert x.size(0) == q.size(0)
x = self.out(x)
x = rearrange(x, "(B h w) t C -> B C t h w", B=B, h=H, w=W)
return x
class AttentionBlock(nn.Module):
def __init__(
self,
dim: int,
**attn_kwargs,
) -> None:
super().__init__()
self.norm = norm_fn(dim)
self.attn = Attention(dim, **attn_kwargs)
def forward(self, x: torch.Tensor) -> torch.Tensor:
return x + self.attn(self.norm(x))
class CausalUpsampleBlock(nn.Module):
def __init__(
self,
@@ -244,14 +325,9 @@ class CausalUpsampleBlock(nn.Module):
return x
def block_fn(channels, *, has_attention: bool = False, **block_kwargs):
assert has_attention is False #NOTE: if this is ever true add back the attention code.
attn_block = None #AttentionBlock(channels) if has_attention else None
return ResBlock(
channels, affine=True, attn_block=attn_block, **block_kwargs
)
def block_fn(channels, *, affine: bool = True, has_attention: bool = False, **block_kwargs):
attn_block = AttentionBlock(channels) if has_attention else None
return ResBlock(channels, affine=affine, attn_block=attn_block, **block_kwargs)
class DownsampleBlock(nn.Module):
@@ -288,8 +364,9 @@ class DownsampleBlock(nn.Module):
out_channels=out_channels,
kernel_size=(temporal_reduction, spatial_reduction, spatial_reduction),
stride=(temporal_reduction, spatial_reduction, spatial_reduction),
# First layer in each block always uses replicate padding
padding_mode="replicate",
bias=True,
bias=block_kwargs["bias"],
)
)
@@ -382,7 +459,7 @@ class Decoder(nn.Module):
blocks = []
first_block = [
nn.Conv3d(latent_dim, ch[-1], kernel_size=(1, 1, 1))
ops.Conv3d(latent_dim, ch[-1], kernel_size=(1, 1, 1))
] # Input layer.
# First set of blocks preserve channel count.
for _ in range(num_res_blocks[-1]):
@@ -452,11 +529,165 @@ class Decoder(nn.Module):
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 = None #TODO once the model releases
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,
@@ -474,7 +705,7 @@ class VideoVAE(nn.Module):
)
def encode(self, x):
return self.encoder(x)
return self.encoder(x).mode()
def decode(self, x):
return self.decoder(x)