| | from typing import Callable, Iterable, Union |
| |
|
| | import torch |
| | from einops import rearrange, repeat |
| |
|
| | from generative_models.sgm.modules.diffusionmodules.model import ( |
| | XFORMERS_IS_AVAILABLE, |
| | AttnBlock, |
| | Decoder, |
| | MemoryEfficientAttnBlock, |
| | ResnetBlock, |
| | ) |
| | from generative_models.sgm.modules.diffusionmodules.openaimodel import ResBlock, timestep_embedding |
| | from generative_models.sgm.modules.video_attention import VideoTransformerBlock |
| | from generative_models.sgm.util import partialclass |
| |
|
| |
|
| | 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") |
| |
|
| |
|
| | class VideoBlock(AttnBlock): |
| | def __init__( |
| | self, in_channels: int, alpha: float = 0, merge_strategy: str = "learned" |
| | ): |
| | super().__init__(in_channels) |
| | |
| | self.time_mix_block = VideoTransformerBlock( |
| | dim=in_channels, |
| | n_heads=1, |
| | d_head=in_channels, |
| | checkpoint=False, |
| | ff_in=True, |
| | attn_mode="softmax", |
| | ) |
| |
|
| | time_embed_dim = self.in_channels * 4 |
| | self.video_time_embed = torch.nn.Sequential( |
| | torch.nn.Linear(self.in_channels, time_embed_dim), |
| | torch.nn.SiLU(), |
| | torch.nn.Linear(time_embed_dim, self.in_channels), |
| | ) |
| |
|
| | 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 forward(self, x, timesteps, skip_video=False): |
| | if skip_video: |
| | return super().forward(x) |
| |
|
| | x_in = x |
| | x = self.attention(x) |
| | h, w = x.shape[2:] |
| | x = rearrange(x, "b c h w -> b (h w) c") |
| |
|
| | x_mix = x |
| | num_frames = torch.arange(timesteps, device=x.device) |
| | num_frames = repeat(num_frames, "t -> b t", b=x.shape[0] // timesteps) |
| | num_frames = rearrange(num_frames, "b t -> (b t)") |
| | t_emb = timestep_embedding(num_frames, self.in_channels, repeat_only=False) |
| | emb = self.video_time_embed(t_emb) |
| | emb = emb[:, None, :] |
| | x_mix = x_mix + emb |
| |
|
| | alpha = self.get_alpha() |
| | x_mix = self.time_mix_block(x_mix, timesteps=timesteps) |
| | x = alpha * x + (1.0 - alpha) * x_mix |
| |
|
| | x = rearrange(x, "b (h w) c -> b c h w", h=h, w=w) |
| | x = self.proj_out(x) |
| |
|
| | return x_in + x |
| |
|
| | def get_alpha( |
| | self, |
| | ): |
| | if self.merge_strategy == "fixed": |
| | return self.mix_factor |
| | elif self.merge_strategy == "learned": |
| | return torch.sigmoid(self.mix_factor) |
| | else: |
| | raise NotImplementedError(f"unknown merge strategy {self.merge_strategy}") |
| |
|
| |
|
| | class MemoryEfficientVideoBlock(MemoryEfficientAttnBlock): |
| | def __init__( |
| | self, in_channels: int, alpha: float = 0, merge_strategy: str = "learned" |
| | ): |
| | super().__init__(in_channels) |
| | |
| | self.time_mix_block = VideoTransformerBlock( |
| | dim=in_channels, |
| | n_heads=1, |
| | d_head=in_channels, |
| | checkpoint=False, |
| | ff_in=True, |
| | attn_mode="softmax-xformers", |
| | ) |
| |
|
| | time_embed_dim = self.in_channels * 4 |
| | self.video_time_embed = torch.nn.Sequential( |
| | torch.nn.Linear(self.in_channels, time_embed_dim), |
| | torch.nn.SiLU(), |
| | torch.nn.Linear(time_embed_dim, self.in_channels), |
| | ) |
| |
|
| | 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 forward(self, x, timesteps, skip_time_block=False): |
| | if skip_time_block: |
| | return super().forward(x) |
| |
|
| | x_in = x |
| | x = self.attention(x) |
| | h, w = x.shape[2:] |
| | x = rearrange(x, "b c h w -> b (h w) c") |
| |
|
| | x_mix = x |
| | num_frames = torch.arange(timesteps, device=x.device) |
| | num_frames = repeat(num_frames, "t -> b t", b=x.shape[0] // timesteps) |
| | num_frames = rearrange(num_frames, "b t -> (b t)") |
| | t_emb = timestep_embedding(num_frames, self.in_channels, repeat_only=False) |
| | emb = self.video_time_embed(t_emb) |
| | emb = emb[:, None, :] |
| | x_mix = x_mix + emb |
| |
|
| | alpha = self.get_alpha() |
| | x_mix = self.time_mix_block(x_mix, timesteps=timesteps) |
| | x = alpha * x + (1.0 - alpha) * x_mix |
| |
|
| | x = rearrange(x, "b (h w) c -> b c h w", h=h, w=w) |
| | x = self.proj_out(x) |
| |
|
| | return x_in + x |
| |
|
| | def get_alpha( |
| | self, |
| | ): |
| | if self.merge_strategy == "fixed": |
| | return self.mix_factor |
| | elif self.merge_strategy == "learned": |
| | return torch.sigmoid(self.mix_factor) |
| | else: |
| | raise NotImplementedError(f"unknown merge strategy {self.merge_strategy}") |
| |
|
| |
|
| | def make_time_attn( |
| | in_channels, |
| | attn_type="vanilla", |
| | attn_kwargs=None, |
| | alpha: float = 0, |
| | merge_strategy: str = "learned", |
| | ): |
| | assert attn_type in [ |
| | "vanilla", |
| | "vanilla-xformers", |
| | ], f"attn_type {attn_type} not supported for spatio-temporal attention" |
| | print( |
| | f"making spatial and temporal attention of type '{attn_type}' with {in_channels} in_channels" |
| | ) |
| | if not XFORMERS_IS_AVAILABLE and attn_type == "vanilla-xformers": |
| | print( |
| | f"Attention mode '{attn_type}' is not available. Falling back to vanilla attention. " |
| | f"This is not a problem in Pytorch >= 2.0. FYI, you are running with PyTorch version {torch.__version__}" |
| | ) |
| | attn_type = "vanilla" |
| |
|
| | if attn_type == "vanilla": |
| | assert attn_kwargs is None |
| | return partialclass( |
| | VideoBlock, in_channels, alpha=alpha, merge_strategy=merge_strategy |
| | ) |
| | elif attn_type == "vanilla-xformers": |
| | print(f"building MemoryEfficientAttnBlock with {in_channels} in_channels...") |
| | return partialclass( |
| | MemoryEfficientVideoBlock, |
| | in_channels, |
| | alpha=alpha, |
| | merge_strategy=merge_strategy, |
| | ) |
| | else: |
| | return NotImplementedError() |
| |
|
| |
|
| | class Conv2DWrapper(torch.nn.Conv2d): |
| | def forward(self, input: torch.Tensor, **kwargs) -> torch.Tensor: |
| | return super().forward(input) |
| |
|
| |
|
| | class VideoDecoder(Decoder): |
| | available_time_modes = ["all", "conv-only", "attn-only"] |
| |
|
| | def __init__( |
| | self, |
| | *args, |
| | video_kernel_size: Union[int, list] = 3, |
| | alpha: float = 0.0, |
| | merge_strategy: str = "learned", |
| | time_mode: str = "conv-only", |
| | **kwargs, |
| | ): |
| | self.video_kernel_size = video_kernel_size |
| | self.alpha = alpha |
| | self.merge_strategy = merge_strategy |
| | self.time_mode = time_mode |
| | assert ( |
| | self.time_mode in self.available_time_modes |
| | ), f"time_mode parameter has to be in {self.available_time_modes}" |
| | super().__init__(*args, **kwargs) |
| |
|
| | def get_last_layer(self, skip_time_mix=False, **kwargs): |
| | if self.time_mode == "attn-only": |
| | raise NotImplementedError("TODO") |
| | else: |
| | return ( |
| | self.conv_out.time_mix_conv.weight |
| | if not skip_time_mix |
| | else self.conv_out.weight |
| | ) |
| |
|
| | def _make_attn(self) -> Callable: |
| | if self.time_mode not in ["conv-only", "only-last-conv"]: |
| | return partialclass( |
| | make_time_attn, |
| | alpha=self.alpha, |
| | merge_strategy=self.merge_strategy, |
| | ) |
| | else: |
| | return super()._make_attn() |
| |
|
| | def _make_conv(self) -> Callable: |
| | if self.time_mode != "attn-only": |
| | return partialclass(AE3DConv, video_kernel_size=self.video_kernel_size) |
| | else: |
| | return Conv2DWrapper |
| |
|
| | def _make_resblock(self) -> Callable: |
| | if self.time_mode not in ["attn-only", "only-last-conv"]: |
| | return partialclass( |
| | VideoResBlock, |
| | video_kernel_size=self.video_kernel_size, |
| | alpha=self.alpha, |
| | merge_strategy=self.merge_strategy, |
| | ) |
| | else: |
| | return super()._make_resblock() |
