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# Adapted from CogVideo
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
# --------------------------------------------------------
# References:
# CogVideo: https://github.com/THUDM/CogVideo
# diffusers: https://github.com/huggingface/diffusers
# --------------------------------------------------------
from typing import Any, Dict, Optional, Union
import torch
from diffusers.configuration_utils import ConfigMixin, register_to_config
from diffusers.models.attention import Attention, FeedForward
from diffusers.models.embeddings import TimestepEmbedding, Timesteps
from diffusers.models.modeling_outputs import Transformer2DModelOutput
from diffusers.models.modeling_utils import ModelMixin
from diffusers.utils import is_torch_version, logging
from diffusers.utils.torch_utils import maybe_allow_in_graph
from torch import nn
from .modules import AdaLayerNorm, CogVideoXLayerNormZero, CogVideoXPatchEmbed, get_3d_sincos_pos_embed
logger = logging.get_logger(__name__) # pylint: disable=invalid-name
@maybe_allow_in_graph
class CogVideoXBlock(nn.Module):
r"""
Transformer block used in [CogVideoX](https://github.com/THUDM/CogVideo) model.
Parameters:
dim (`int`): The number of channels in the input and output.
num_attention_heads (`int`): The number of heads to use for multi-head attention.
attention_head_dim (`int`): The number of channels in each head.
dropout (`float`, *optional*, defaults to 0.0): The dropout probability to use.
activation_fn (`str`, *optional*, defaults to `"geglu"`): Activation function to be used in feed-forward.
attention_bias (:
obj: `bool`, *optional*, defaults to `False`): Configure if the attentions should contain a bias parameter.
qk_norm (`bool`, defaults to `True`):
Whether or not to use normalization after query and key projections in Attention.
norm_elementwise_affine (`bool`, defaults to `True`):
Whether to use learnable elementwise affine parameters for normalization.
norm_eps (`float`, defaults to `1e-5`):
Epsilon value for normalization layers.
final_dropout (`bool` defaults to `False`):
Whether to apply a final dropout after the last feed-forward layer.
ff_inner_dim (`int`, *optional*, defaults to `None`):
Custom hidden dimension of Feed-forward layer. If not provided, `4 * dim` is used.
ff_bias (`bool`, defaults to `True`):
Whether or not to use bias in Feed-forward layer.
attention_out_bias (`bool`, defaults to `True`):
Whether or not to use bias in Attention output projection layer.
"""
def __init__(
self,
dim: int,
num_attention_heads: int,
attention_head_dim: int,
time_embed_dim: int,
dropout: float = 0.0,
activation_fn: str = "gelu-approximate",
attention_bias: bool = False,
qk_norm: bool = True,
norm_elementwise_affine: bool = True,
norm_eps: float = 1e-5,
final_dropout: bool = True,
ff_inner_dim: Optional[int] = None,
ff_bias: bool = True,
attention_out_bias: bool = True,
):
super().__init__()
# 1. Self Attention
self.norm1 = CogVideoXLayerNormZero(time_embed_dim, dim, norm_elementwise_affine, norm_eps, bias=True)
self.attn1 = Attention(
query_dim=dim,
dim_head=attention_head_dim,
heads=num_attention_heads,
qk_norm="layer_norm" if qk_norm else None,
eps=1e-6,
bias=attention_bias,
out_bias=attention_out_bias,
)
# 2. Feed Forward
self.norm2 = CogVideoXLayerNormZero(time_embed_dim, dim, norm_elementwise_affine, norm_eps, bias=True)
self.ff = FeedForward(
dim,
dropout=dropout,
activation_fn=activation_fn,
final_dropout=final_dropout,
inner_dim=ff_inner_dim,
bias=ff_bias,
)
def forward(
self,
hidden_states: torch.Tensor,
encoder_hidden_states: torch.Tensor,
temb: torch.Tensor,
) -> torch.Tensor:
norm_hidden_states, norm_encoder_hidden_states, gate_msa, enc_gate_msa = self.norm1(
hidden_states, encoder_hidden_states, temb
)
# attention
text_length = norm_encoder_hidden_states.size(1)
# CogVideoX uses concatenated text + video embeddings with self-attention instead of using
# them in cross-attention individually
norm_hidden_states = torch.cat([norm_encoder_hidden_states, norm_hidden_states], dim=1)
attn_output = self.attn1(
hidden_states=norm_hidden_states,
encoder_hidden_states=None,
)
hidden_states = hidden_states + gate_msa * attn_output[:, text_length:]
encoder_hidden_states = encoder_hidden_states + enc_gate_msa * attn_output[:, :text_length]
# norm & modulate
norm_hidden_states, norm_encoder_hidden_states, gate_ff, enc_gate_ff = self.norm2(
hidden_states, encoder_hidden_states, temb
)
# feed-forward
norm_hidden_states = torch.cat([norm_encoder_hidden_states, norm_hidden_states], dim=1)
ff_output = self.ff(norm_hidden_states)
hidden_states = hidden_states + gate_ff * ff_output[:, text_length:]
encoder_hidden_states = encoder_hidden_states + enc_gate_ff * ff_output[:, :text_length]
return hidden_states, encoder_hidden_states
class CogVideoXTransformer3DModel(ModelMixin, ConfigMixin):
"""
A Transformer model for video-like data in [CogVideoX](https://github.com/THUDM/CogVideo).
Parameters:
num_attention_heads (`int`, *optional*, defaults to 16): The number of heads to use for multi-head attention.
attention_head_dim (`int`, *optional*, defaults to 88): The number of channels in each head.
in_channels (`int`, *optional*):
The number of channels in the input.
out_channels (`int`, *optional*):
The number of channels in the output.
num_layers (`int`, *optional*, defaults to 1): The number of layers of Transformer blocks to use.
dropout (`float`, *optional*, defaults to 0.0): The dropout probability to use.
cross_attention_dim (`int`, *optional*): The number of `encoder_hidden_states` dimensions to use.
attention_bias (`bool`, *optional*):
Configure if the `TransformerBlocks` attention should contain a bias parameter.
sample_size (`int`, *optional*): The width of the latent images (specify if the input is **discrete**).
This is fixed during training since it is used to learn a number of position embeddings.
patch_size (`int`, *optional*):
The size of the patches to use in the patch embedding layer.
activation_fn (`str`, *optional*, defaults to `"geglu"`): Activation function to use in feed-forward.
num_embeds_ada_norm ( `int`, *optional*):
The number of diffusion steps used during training. Pass if at least one of the norm_layers is
`AdaLayerNorm`. This is fixed during training since it is used to learn a number of embeddings that are
added to the hidden states. During inference, you can denoise for up to but not more steps than
`num_embeds_ada_norm`.
norm_type (`str`, *optional*, defaults to `"layer_norm"`):
The type of normalization to use. Options are `"layer_norm"` or `"ada_layer_norm"`.
norm_elementwise_affine (`bool`, *optional*, defaults to `True`):
Whether or not to use elementwise affine in normalization layers.
norm_eps (`float`, *optional*, defaults to 1e-5): The epsilon value to use in normalization layers.
caption_channels (`int`, *optional*):
The number of channels in the caption embeddings.
video_length (`int`, *optional*):
The number of frames in the video-like data.
"""
_supports_gradient_checkpointing = True
@register_to_config
def __init__(
self,
num_attention_heads: int = 30,
attention_head_dim: int = 64,
in_channels: Optional[int] = 16,
out_channels: Optional[int] = 16,
flip_sin_to_cos: bool = True,
freq_shift: int = 0,
time_embed_dim: int = 512,
text_embed_dim: int = 4096,
num_layers: int = 30,
dropout: float = 0.0,
attention_bias: bool = True,
sample_width: int = 90,
sample_height: int = 60,
sample_frames: int = 49,
patch_size: int = 2,
temporal_compression_ratio: int = 4,
max_text_seq_length: int = 226,
activation_fn: str = "gelu-approximate",
timestep_activation_fn: str = "silu",
norm_elementwise_affine: bool = True,
norm_eps: float = 1e-5,
spatial_interpolation_scale: float = 1.875,
temporal_interpolation_scale: float = 1.0,
):
super().__init__()
inner_dim = num_attention_heads * attention_head_dim
post_patch_height = sample_height // patch_size
post_patch_width = sample_width // patch_size
post_time_compression_frames = (sample_frames - 1) // temporal_compression_ratio + 1
self.num_patches = post_patch_height * post_patch_width * post_time_compression_frames
# 1. Patch embedding
self.patch_embed = CogVideoXPatchEmbed(patch_size, in_channels, inner_dim, text_embed_dim, bias=True)
self.embedding_dropout = nn.Dropout(dropout)
# 2. 3D positional embeddings
spatial_pos_embedding = get_3d_sincos_pos_embed(
inner_dim,
(post_patch_width, post_patch_height),
post_time_compression_frames,
spatial_interpolation_scale,
temporal_interpolation_scale,
)
spatial_pos_embedding = torch.from_numpy(spatial_pos_embedding).flatten(0, 1)
pos_embedding = torch.zeros(1, max_text_seq_length + self.num_patches, inner_dim, requires_grad=False)
pos_embedding.data[:, max_text_seq_length:].copy_(spatial_pos_embedding)
self.register_buffer("pos_embedding", pos_embedding, persistent=False)
# 3. Time embeddings
self.time_proj = Timesteps(inner_dim, flip_sin_to_cos, freq_shift)
self.time_embedding = TimestepEmbedding(inner_dim, time_embed_dim, timestep_activation_fn)
# 4. Define spatio-temporal transformers blocks
self.transformer_blocks = nn.ModuleList(
[
CogVideoXBlock(
dim=inner_dim,
num_attention_heads=num_attention_heads,
attention_head_dim=attention_head_dim,
time_embed_dim=time_embed_dim,
dropout=dropout,
activation_fn=activation_fn,
attention_bias=attention_bias,
norm_elementwise_affine=norm_elementwise_affine,
norm_eps=norm_eps,
)
for _ in range(num_layers)
]
)
self.norm_final = nn.LayerNorm(inner_dim, norm_eps, norm_elementwise_affine)
# 5. Output blocks
self.norm_out = AdaLayerNorm(
embedding_dim=time_embed_dim,
output_dim=2 * inner_dim,
norm_elementwise_affine=norm_elementwise_affine,
norm_eps=norm_eps,
chunk_dim=1,
)
self.proj_out = nn.Linear(inner_dim, patch_size * patch_size * out_channels)
self.gradient_checkpointing = False
def _set_gradient_checkpointing(self, module, value=False):
self.gradient_checkpointing = value
def forward(
self,
hidden_states: torch.Tensor,
encoder_hidden_states: torch.Tensor,
timestep: Union[int, float, torch.LongTensor],
timestep_cond: Optional[torch.Tensor] = None,
return_dict: bool = True,
):
batch_size, num_frames, channels, height, width = hidden_states.shape
# 1. Time embedding
timesteps = timestep
t_emb = self.time_proj(timesteps)
# timesteps does not contain any weights and will always return f32 tensors
# but time_embedding might actually be running in fp16. so we need to cast here.
# there might be better ways to encapsulate this.
t_emb = t_emb.to(dtype=hidden_states.dtype)
emb = self.time_embedding(t_emb, timestep_cond)
# 2. Patch embedding
hidden_states = self.patch_embed(encoder_hidden_states, hidden_states)
# 3. Position embedding
seq_length = height * width * num_frames // (self.config.patch_size**2)
pos_embeds = self.pos_embedding[:, : self.config.max_text_seq_length + seq_length]
hidden_states = hidden_states + pos_embeds
hidden_states = self.embedding_dropout(hidden_states)
encoder_hidden_states = hidden_states[:, : self.config.max_text_seq_length]
hidden_states = hidden_states[:, self.config.max_text_seq_length :]
# 5. Transformer blocks
for i, block in enumerate(self.transformer_blocks):
if self.training and self.gradient_checkpointing:
def create_custom_forward(module):
def custom_forward(*inputs):
return module(*inputs)
return custom_forward
ckpt_kwargs: Dict[str, Any] = {"use_reentrant": False} if is_torch_version(">=", "1.11.0") else {}
hidden_states, encoder_hidden_states = torch.utils.checkpoint.checkpoint(
create_custom_forward(block),
hidden_states,
encoder_hidden_states,
emb,
**ckpt_kwargs,
)
else:
hidden_states, encoder_hidden_states = block(
hidden_states=hidden_states,
encoder_hidden_states=encoder_hidden_states,
temb=emb,
)
hidden_states = self.norm_final(hidden_states)
# 6. Final block
hidden_states = self.norm_out(hidden_states, temb=emb)
hidden_states = self.proj_out(hidden_states)
# 7. Unpatchify
p = self.config.patch_size
output = hidden_states.reshape(batch_size, num_frames, height // p, width // p, channels, p, p)
output = output.permute(0, 1, 4, 2, 5, 3, 6).flatten(5, 6).flatten(3, 4)
if not return_dict:
return (output,)
return Transformer2DModelOutput(sample=output)
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