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Python

# SPDX-License-Identifier: Apache-2.0
import copy
import math
from typing import Any
import torch
import torch.nn as nn
import fastvideo.envs as envs
from fastvideo.attention import (DistributedAttention, DistributedAttention_VSA, LocalAttention)
from fastvideo.configs.models.dits import WanVideoConfig
from fastvideo.distributed.communication_op import (sequence_model_parallel_all_gather_with_unpad,
sequence_model_parallel_shard)
from fastvideo.layers.layernorm import (FP32LayerNorm, LayerNormScaleShift, RMSNorm, ScaleResidual,
ScaleResidualLayerNormScaleShift)
from fastvideo.layers.linear import ReplicatedLinear
# from torch.nn import RMSNorm
# TODO: RMSNorm ....
from fastvideo.layers.mlp import MLP
from fastvideo.layers.rotary_embedding import get_rotary_pos_embed
from fastvideo.layers.visual_embedding import (ModulateProjection, PatchEmbed, TimestepEmbedder)
from fastvideo.logger import init_logger
from fastvideo.models.dits.base import BaseDiT
from fastvideo.platforms import AttentionBackendEnum, current_platform
from fastvideo.layers.quantization import QuantizationConfig
from fastvideo.distributed.parallel_state import get_sp_world_size
logger = init_logger(__name__)
class WanImageEmbedding(torch.nn.Module):
def __init__(self, in_features: int, out_features: int):
super().__init__()
self.norm1 = FP32LayerNorm(in_features)
self.ff = MLP(in_features, in_features, out_features, act_type="gelu")
self.norm2 = FP32LayerNorm(out_features)
def forward(self, encoder_hidden_states_image: torch.Tensor) -> torch.Tensor:
dtype = encoder_hidden_states_image.dtype
hidden_states = self.norm1(encoder_hidden_states_image)
hidden_states = self.ff(hidden_states)
hidden_states = self.norm2(hidden_states).to(dtype)
return hidden_states
class WanTimeTextImageEmbedding(nn.Module):
def __init__(
self,
dim: int,
time_freq_dim: int,
text_embed_dim: int,
image_embed_dim: int | None = None,
*,
r_embedder: bool = False,
r_embedder_fusion: str = "additive",
r_embedder_gate_value: float = 0.25,
r_embedder_deltatime_type: str = "r",
):
super().__init__()
self.time_embedder = TimestepEmbedder(dim, frequency_embedding_size=time_freq_dim, act_layer="silu")
self.time_modulation = ModulateProjection(dim, factor=6, act_layer="silu")
self.text_embedder = MLP(text_embed_dim, dim, dim, bias=True,
act_type="gelu_pytorch_tanh") if text_embed_dim > 0 else None
self.image_embedder = None
if image_embed_dim is not None:
self.image_embedder = WanImageEmbedding(image_embed_dim, dim)
# AnyFlow dual-timestep support. When r_embedder is False the forward
# path bypasses delta_embedder entirely and the output is byte-identical
# to the legacy single-timestep implementation.
self._r_embedder_enabled = bool(r_embedder)
self._r_embedder_fusion = r_embedder_fusion
self._r_embedder_deltatime_type = r_embedder_deltatime_type
if self._r_embedder_enabled:
if r_embedder_fusion not in ("additive", "gated"):
raise ValueError("r_embedder_fusion must be one of {additive, gated}, "
f"got {r_embedder_fusion!r}")
if r_embedder_deltatime_type not in ("r", "t-r"):
raise ValueError("r_embedder_deltatime_type must be one of {r, t-r}, "
f"got {r_embedder_deltatime_type!r}")
# Deep-copy preserves identical initialization with time_embedder,
# matching AnyFlow reference setup_flowmap_model() behavior.
self.delta_embedder = copy.deepcopy(self.time_embedder)
# Non-persistent buffer — gate is a hyperparameter, not learned.
self.register_buffer(
"_r_embedder_gate",
torch.tensor(float(r_embedder_gate_value)),
persistent=False,
)
else:
self.delta_embedder = None
def forward(
self,
timestep: torch.Tensor,
encoder_hidden_states: torch.Tensor,
encoder_hidden_states_image: torch.Tensor | None = None,
timestep_seq_len: int | None = None,
r_timestep: torch.Tensor | None = None,
):
temb = self.time_embedder(timestep, timestep_seq_len)
if self._r_embedder_enabled and r_timestep is not None:
assert self.delta_embedder is not None
if self._r_embedder_deltatime_type == "r":
delta_input = r_timestep
else:
delta_input = timestep - r_timestep
delta_emb = self.delta_embedder(delta_input, timestep_seq_len)
gate = self._r_embedder_gate
if self._r_embedder_fusion == "gated":
temb = (1.0 - gate) * temb + gate * delta_emb
else:
# Additive (additional channel, no convex blend).
temb = temb + gate * delta_emb
timestep_proj = self.time_modulation(temb)
if self.text_embedder is not None:
encoder_hidden_states = self.text_embedder(encoder_hidden_states)
else:
encoder_hidden_states = torch.zeros((timestep.shape[0], 0, temb.shape[-1]),
device=temb.device,
dtype=temb.dtype)
if encoder_hidden_states_image is not None:
assert self.image_embedder is not None
encoder_hidden_states_image = self.image_embedder(encoder_hidden_states_image)
return temb, timestep_proj, encoder_hidden_states, encoder_hidden_states_image
class WanSelfAttention(nn.Module):
def __init__(self,
dim: int,
num_heads: int,
window_size=(-1, -1),
qk_norm=True,
eps=1e-6,
parallel_attention=False,
quant_config: QuantizationConfig | None = None,
prefix: str = "") -> None:
assert dim % num_heads == 0
super().__init__()
self.dim = dim
self.num_heads = num_heads
self.head_dim = dim // num_heads
self.window_size = window_size
self.qk_norm = qk_norm
self.eps = eps
self.parallel_attention = parallel_attention
# layers
self.to_q = ReplicatedLinear(dim, dim, quant_config=quant_config, prefix=f"{prefix}.to_q")
self.to_k = ReplicatedLinear(dim, dim, quant_config=quant_config, prefix=f"{prefix}.to_k")
self.to_v = ReplicatedLinear(dim, dim, quant_config=quant_config, prefix=f"{prefix}.to_v")
self.to_out = ReplicatedLinear(dim, dim, quant_config=quant_config, prefix=f"{prefix}.to_out")
self.norm_q = RMSNorm(dim, eps=eps) if qk_norm else nn.Identity()
self.norm_k = RMSNorm(dim, eps=eps) if qk_norm else nn.Identity()
# Scaled dot product attention
self.attn = LocalAttention(num_heads=num_heads,
head_size=self.head_dim,
dropout_rate=0,
softmax_scale=None,
causal=False,
supported_attention_backends=(AttentionBackendEnum.FLASH_ATTN,
AttentionBackendEnum.TORCH_SDPA))
def forward(self, x: torch.Tensor, context: torch.Tensor, context_lens: int):
r"""
Args:
x(Tensor): Shape [B, L, num_heads, C / num_heads]
seq_lens(Tensor): Shape [B]
grid_sizes(Tensor): Shape [B, 3], the second dimension contains (F, H, W)
freqs(Tensor): Rope freqs, shape [1024, C / num_heads / 2]
"""
pass
class WanT2VCrossAttention(WanSelfAttention):
def forward(self, x, context, context_lens, crossattn_cache=None):
r"""
Args:
x(Tensor): Shape [B, L1, C]
context(Tensor): Shape [B, L2, C]
context_lens(Tensor): Shape [B]
"""
b, n, d = x.size(0), self.num_heads, self.head_dim
# compute query, key, value
q = self.norm_q(self.to_q(x)[0]).view(b, -1, n, d)
if crossattn_cache is not None:
if not crossattn_cache["is_init"]:
crossattn_cache["is_init"] = True
k = self.norm_k(self.to_k(context)[0]).view(b, -1, n, d)
v = self.to_v(context)[0].view(b, -1, n, d)
crossattn_cache["k"] = k
crossattn_cache["v"] = v
else:
k = crossattn_cache["k"]
v = crossattn_cache["v"]
else:
k = self.norm_k(self.to_k(context)[0]).view(b, -1, n, d)
v = self.to_v(context)[0].view(b, -1, n, d)
# compute attention
x = self.attn(q, k, v) if k.size(1) > 0 else torch.zeros_like(q)
# output
x = x.flatten(2)
x, _ = self.to_out(x)
return x
class WanI2VCrossAttention(WanSelfAttention):
def __init__(
self,
dim: int,
num_heads: int,
window_size=(-1, -1),
qk_norm=True,
eps=1e-6,
supported_attention_backends: tuple[AttentionBackendEnum, ...]
| None = None,
quant_config: QuantizationConfig | None = None,
prefix: str = "",
) -> None:
super().__init__(dim,
num_heads,
window_size,
qk_norm,
eps,
supported_attention_backends,
quant_config=quant_config,
prefix=prefix)
self.add_k_proj = ReplicatedLinear(dim, dim, quant_config=quant_config, prefix=f"{prefix}.add_k_proj")
self.add_v_proj = ReplicatedLinear(dim, dim, quant_config=quant_config, prefix=f"{prefix}.add_v_proj")
self.norm_added_k = RMSNorm(dim, eps=eps) if qk_norm else nn.Identity()
self.norm_added_q = RMSNorm(dim, eps=eps) if qk_norm else nn.Identity()
def forward(self, x, context, context_lens):
r"""
Args:
x(Tensor): Shape [B, L1, C]
context(Tensor): Shape [B, L2, C]
context_lens(Tensor): Shape [B]
"""
context_img = context[:, :257]
context = context[:, 257:]
b, n, d = x.size(0), self.num_heads, self.head_dim
# compute query, key, value
q = self.norm_q(self.to_q(x)[0]).view(b, -1, n, d)
k = self.norm_k(self.to_k(context)[0]).view(b, -1, n, d)
v = self.to_v(context)[0].view(b, -1, n, d)
k_img = self.norm_added_k(self.add_k_proj(context_img)[0]).view(b, -1, n, d)
v_img = self.add_v_proj(context_img)[0].view(b, -1, n, d)
img_x = self.attn(q, k_img, v_img)
# compute attention
x = self.attn(q, k, v) if k.size(1) > 0 else torch.zeros_like(q)
# output
x = x.flatten(2)
img_x = img_x.flatten(2)
x = x + img_x
x, _ = self.to_out(x)
return x
class WanTransformerBlock(nn.Module):
def __init__(self,
dim: int,
ffn_dim: int,
num_heads: int,
qk_norm: str = "rms_norm_across_heads",
cross_attn_norm: bool = False,
eps: float = 1e-6,
added_kv_proj_dim: int | None = None,
supported_attention_backends: tuple[AttentionBackendEnum, ...]
| None = None,
quant_config: QuantizationConfig | None = None,
prefix: str = ""):
super().__init__()
# 1. Self-attention
self.norm1 = FP32LayerNorm(dim, eps, elementwise_affine=False)
self.to_q = ReplicatedLinear(dim, dim, bias=True, quant_config=quant_config, prefix=f"{prefix}.to_q")
self.to_k = ReplicatedLinear(dim, dim, bias=True, quant_config=quant_config, prefix=f"{prefix}.to_k")
self.to_v = ReplicatedLinear(dim, dim, bias=True, quant_config=quant_config, prefix=f"{prefix}.to_v")
self.to_out = ReplicatedLinear(dim, dim, bias=True, quant_config=quant_config, prefix=f"{prefix}.to_out")
self.attn1 = DistributedAttention(num_heads=num_heads,
head_size=dim // num_heads,
causal=False,
supported_attention_backends=supported_attention_backends,
prefix=f"{prefix}.attn1")
self.hidden_dim = dim
self.num_attention_heads = num_heads
dim_head = dim // num_heads
if qk_norm == "rms_norm":
self.norm_q = RMSNorm(dim_head, eps=eps)
self.norm_k = RMSNorm(dim_head, eps=eps)
elif qk_norm == "rms_norm_across_heads":
# LTX applies qk norm across all heads
self.norm_q = RMSNorm(dim, eps=eps)
self.norm_k = RMSNorm(dim, eps=eps)
else:
print("QK Norm type not supported")
raise Exception
assert cross_attn_norm is True
self.self_attn_residual_norm = ScaleResidualLayerNormScaleShift(dim,
norm_type="layer",
eps=eps,
elementwise_affine=True,
dtype=torch.float32,
compute_dtype=torch.float32)
# 2. Cross-attention
if added_kv_proj_dim is not None:
# I2V
self.attn2 = WanI2VCrossAttention(dim,
num_heads,
qk_norm=qk_norm,
eps=eps,
quant_config=quant_config,
prefix=f"{prefix}.attn2")
else:
# T2V
self.attn2 = WanT2VCrossAttention(dim,
num_heads,
qk_norm=qk_norm,
eps=eps,
quant_config=quant_config,
prefix=f"{prefix}.attn2")
self.cross_attn_residual_norm = ScaleResidualLayerNormScaleShift(dim,
norm_type="layer",
eps=eps,
elementwise_affine=False,
dtype=torch.float32,
compute_dtype=torch.float32)
# 3. Feed-forward
self.ffn = MLP(dim, ffn_dim, act_type="gelu_pytorch_tanh", quant_config=quant_config, prefix=f"{prefix}.ffn")
self.mlp_residual = ScaleResidual()
self.scale_shift_table = nn.Parameter(torch.randn(1, 6, dim) / dim**0.5)
def forward(
self,
hidden_states: torch.Tensor,
encoder_hidden_states: torch.Tensor,
temb: torch.Tensor,
freqs_cis: tuple[torch.Tensor, torch.Tensor],
original_seq_len: int,
) -> torch.Tensor:
if hidden_states.dim() == 4:
hidden_states = hidden_states.squeeze(1)
bs, seq_length, _ = hidden_states.shape
orig_dtype = hidden_states.dtype
# assert orig_dtype != torch.float32
if temb.dim() == 4:
# temb: batch_size, seq_len, 6, inner_dim (wan2.2 ti2v)
shift_msa, scale_msa, gate_msa, c_shift_msa, c_scale_msa, c_gate_msa = (
self.scale_shift_table.unsqueeze(0) + temb.float()).chunk(6, dim=2)
# batch_size, seq_len, 1, inner_dim
shift_msa = shift_msa.squeeze(2)
scale_msa = scale_msa.squeeze(2)
gate_msa = gate_msa.squeeze(2)
c_shift_msa = c_shift_msa.squeeze(2)
c_scale_msa = c_scale_msa.squeeze(2)
c_gate_msa = c_gate_msa.squeeze(2)
else:
# temb: batch_size, 6, inner_dim (wan2.1/wan2.2 14B)
e = self.scale_shift_table + temb.float()
shift_msa, scale_msa, gate_msa, c_shift_msa, c_scale_msa, c_gate_msa = e.chunk(6, dim=1)
assert shift_msa.dtype == torch.float32
# 1. Self-attention
norm_hidden_states = (self.norm1(hidden_states.float()) * (1 + scale_msa) + shift_msa).to(orig_dtype)
query, _ = self.to_q(norm_hidden_states)
key, _ = self.to_k(norm_hidden_states)
value, _ = self.to_v(norm_hidden_states)
if self.norm_q is not None:
query = self.norm_q(query)
if self.norm_k is not None:
key = self.norm_k(key)
query = query.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
key = key.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
value = value.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
attn_output, _ = self.attn1(
query,
key,
value,
original_seq_len,
freqs_cis=freqs_cis,
)
attn_output = attn_output.flatten(2)
attn_output, _ = self.to_out(attn_output)
attn_output = attn_output.squeeze(1)
null_shift = null_scale = torch.tensor([0], device=hidden_states.device)
norm_hidden_states, hidden_states = self.self_attn_residual_norm(hidden_states, attn_output, gate_msa,
null_shift, null_scale)
norm_hidden_states, hidden_states = norm_hidden_states.to(orig_dtype), hidden_states.to(orig_dtype)
# 2. Cross-attention
attn_output = self.attn2(norm_hidden_states, context=encoder_hidden_states, context_lens=None)
norm_hidden_states, hidden_states = self.cross_attn_residual_norm(hidden_states, attn_output, 1, c_shift_msa,
c_scale_msa)
norm_hidden_states, hidden_states = norm_hidden_states.to(orig_dtype), hidden_states.to(orig_dtype)
# 3. Feed-forward
ff_output = self.ffn(norm_hidden_states)
hidden_states = self.mlp_residual(hidden_states, ff_output, c_gate_msa)
hidden_states = hidden_states.to(orig_dtype)
return hidden_states
class WanTransformerBlock_VSA(nn.Module):
def __init__(self,
dim: int,
ffn_dim: int,
num_heads: int,
qk_norm: str = "rms_norm_across_heads",
cross_attn_norm: bool = False,
eps: float = 1e-6,
added_kv_proj_dim: int | None = None,
supported_attention_backends: tuple[AttentionBackendEnum, ...]
| None = None,
quant_config: QuantizationConfig | None = None,
prefix: str = ""):
super().__init__()
# 1. Self-attention
self.norm1 = FP32LayerNorm(dim, eps, elementwise_affine=False)
self.to_q = ReplicatedLinear(dim, dim, bias=True, quant_config=quant_config, prefix=f"{prefix}.to_q")
self.to_k = ReplicatedLinear(dim, dim, bias=True, quant_config=quant_config, prefix=f"{prefix}.to_k")
self.to_v = ReplicatedLinear(dim, dim, bias=True, quant_config=quant_config, prefix=f"{prefix}.to_v")
self.to_gate_compress = ReplicatedLinear(dim,
dim,
bias=True,
quant_config=quant_config,
prefix=f"{prefix}.to_gate_compress")
self.to_out = ReplicatedLinear(dim, dim, bias=True, quant_config=quant_config, prefix=f"{prefix}.to_out")
self.attn1 = DistributedAttention_VSA(num_heads=num_heads,
head_size=dim // num_heads,
causal=False,
supported_attention_backends=supported_attention_backends,
prefix=f"{prefix}.attn1")
self.hidden_dim = dim
self.num_attention_heads = num_heads
dim_head = dim // num_heads
if qk_norm == "rms_norm":
self.norm_q = RMSNorm(dim_head, eps=eps)
self.norm_k = RMSNorm(dim_head, eps=eps)
elif qk_norm == "rms_norm_across_heads":
# LTX applies qk norm across all heads
self.norm_q = RMSNorm(dim, eps=eps)
self.norm_k = RMSNorm(dim, eps=eps)
else:
print("QK Norm type not supported")
raise Exception
assert cross_attn_norm is True
self.self_attn_residual_norm = ScaleResidualLayerNormScaleShift(dim,
norm_type="layer",
eps=eps,
elementwise_affine=True,
dtype=torch.float32,
compute_dtype=torch.float32)
# 2. Cross-attention
if added_kv_proj_dim is not None:
# I2V
self.attn2 = WanI2VCrossAttention(dim,
num_heads,
qk_norm=qk_norm,
eps=eps,
quant_config=quant_config,
prefix=f"{prefix}.attn2")
else:
# T2V
self.attn2 = WanT2VCrossAttention(dim,
num_heads,
qk_norm=qk_norm,
eps=eps,
quant_config=quant_config,
prefix=f"{prefix}.attn2")
self.cross_attn_residual_norm = ScaleResidualLayerNormScaleShift(dim,
norm_type="layer",
eps=eps,
elementwise_affine=False,
dtype=torch.float32,
compute_dtype=torch.float32)
# 3. Feed-forward
self.ffn = MLP(dim, ffn_dim, act_type="gelu_pytorch_tanh", quant_config=quant_config, prefix=f"{prefix}.ffn")
self.mlp_residual = ScaleResidual()
self.scale_shift_table = nn.Parameter(torch.randn(1, 6, dim) / dim**0.5)
def forward(
self,
hidden_states: torch.Tensor,
encoder_hidden_states: torch.Tensor,
temb: torch.Tensor,
freqs_cis: tuple[torch.Tensor, torch.Tensor],
original_seq_len: int,
) -> torch.Tensor:
if hidden_states.dim() == 4:
hidden_states = hidden_states.squeeze(1)
bs, seq_length, _ = hidden_states.shape
orig_dtype = hidden_states.dtype
# assert orig_dtype != torch.float32
e = self.scale_shift_table + temb.float()
shift_msa, scale_msa, gate_msa, c_shift_msa, c_scale_msa, c_gate_msa = e.chunk(6, dim=1)
assert shift_msa.dtype == torch.float32
# 1. Self-attention
norm_hidden_states = (self.norm1(hidden_states.float()) * (1 + scale_msa) + shift_msa).to(orig_dtype)
query, _ = self.to_q(norm_hidden_states)
key, _ = self.to_k(norm_hidden_states)
value, _ = self.to_v(norm_hidden_states)
gate_compress, _ = self.to_gate_compress(norm_hidden_states)
if self.norm_q is not None:
query = self.norm_q(query)
if self.norm_k is not None:
key = self.norm_k(key)
query = query.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
key = key.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
value = value.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
gate_compress = gate_compress.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
attn_output, _ = self.attn1(
query,
key,
value,
original_seq_len,
freqs_cis=freqs_cis,
gate_compress=gate_compress,
)
attn_output = attn_output.flatten(2)
attn_output, _ = self.to_out(attn_output)
attn_output = attn_output.squeeze(1)
null_shift = null_scale = torch.tensor([0], device=hidden_states.device)
norm_hidden_states, hidden_states = self.self_attn_residual_norm(hidden_states, attn_output, gate_msa,
null_shift, null_scale)
norm_hidden_states, hidden_states = norm_hidden_states.to(orig_dtype), hidden_states.to(orig_dtype)
# 2. Cross-attention
attn_output = self.attn2(norm_hidden_states, context=encoder_hidden_states, context_lens=None)
norm_hidden_states, hidden_states = self.cross_attn_residual_norm(hidden_states, attn_output, 1, c_shift_msa,
c_scale_msa)
norm_hidden_states, hidden_states = norm_hidden_states.to(orig_dtype), hidden_states.to(orig_dtype)
# 3. Feed-forward
ff_output = self.ffn(norm_hidden_states)
hidden_states = self.mlp_residual(hidden_states, ff_output, c_gate_msa)
hidden_states = hidden_states.to(orig_dtype)
return hidden_states
class WanTransformer3DModel(BaseDiT):
_fsdp_shard_conditions = WanVideoConfig()._fsdp_shard_conditions
_compile_conditions = WanVideoConfig()._compile_conditions
_supported_attention_backends = WanVideoConfig()._supported_attention_backends
param_names_mapping = WanVideoConfig().param_names_mapping
reverse_param_names_mapping = WanVideoConfig().reverse_param_names_mapping
lora_param_names_mapping = WanVideoConfig().lora_param_names_mapping
def __init__(self, config: WanVideoConfig, hf_config: dict[str, Any]) -> None:
super().__init__(config=config, hf_config=hf_config)
self.quant_config = config.quant_config
inner_dim = config.num_attention_heads * config.attention_head_dim
self.hidden_size = config.hidden_size
self.num_attention_heads = config.num_attention_heads
self.in_channels = config.in_channels
self.out_channels = config.out_channels
self.num_channels_latents = config.num_channels_latents
self.patch_size = config.patch_size
self.text_len = config.text_len
assert config.num_attention_heads % get_sp_world_size(
) == 0, f"The number of attention heads ({config.num_attention_heads}) must be divisible by the sequence parallel size ({get_sp_world_size()})"
# 1. Patch & position embedding
self.patch_embedding = PatchEmbed(in_chans=config.in_channels,
embed_dim=inner_dim,
patch_size=config.patch_size,
flatten=False)
# 2. Condition embeddings
self.condition_embedder = WanTimeTextImageEmbedding(
dim=inner_dim,
time_freq_dim=config.freq_dim,
text_embed_dim=config.text_dim,
image_embed_dim=config.image_dim,
r_embedder=config.r_embedder,
r_embedder_fusion=config.r_embedder_fusion,
r_embedder_gate_value=config.r_embedder_gate_value,
r_embedder_deltatime_type=config.r_embedder_deltatime_type,
)
# 3. Transformer blocks
attn_backend = envs.FASTVIDEO_ATTENTION_BACKEND
transformer_block = WanTransformerBlock_VSA if attn_backend == "VIDEO_SPARSE_ATTN" else WanTransformerBlock
self.blocks = nn.ModuleList([
transformer_block(inner_dim,
config.ffn_dim,
config.num_attention_heads,
config.qk_norm,
config.cross_attn_norm,
config.eps,
config.added_kv_proj_dim,
self._supported_attention_backends,
quant_config=config.quant_config,
prefix=f"{config.prefix}.blocks.{i}") for i in range(config.num_layers)
])
# 4. Output norm & projection
self.norm_out = LayerNormScaleShift(inner_dim,
norm_type="layer",
eps=config.eps,
elementwise_affine=False,
dtype=torch.float32,
compute_dtype=torch.float32)
self.proj_out = nn.Linear(inner_dim, config.out_channels * math.prod(config.patch_size))
self.scale_shift_table = nn.Parameter(torch.randn(1, 2, inner_dim) / inner_dim**0.5)
self.gradient_checkpointing = False
self.__post_init__()
def forward(self,
hidden_states: torch.Tensor,
encoder_hidden_states: torch.Tensor | list[torch.Tensor],
timestep: torch.LongTensor,
encoder_hidden_states_image: torch.Tensor | list[torch.Tensor]
| None = None,
guidance=None,
r_timestep: torch.Tensor | None = None,
**kwargs) -> torch.Tensor:
orig_dtype = hidden_states.dtype
if encoder_hidden_states is not None and not isinstance(encoder_hidden_states, torch.Tensor):
encoder_hidden_states = encoder_hidden_states[0]
if isinstance(encoder_hidden_states_image, list):
encoder_hidden_states_image = (encoder_hidden_states_image[0]
if len(encoder_hidden_states_image) > 0 else None)
batch_size, num_channels, num_frames, height, width = hidden_states.shape
p_t, p_h, p_w = self.patch_size
post_patch_num_frames = num_frames // p_t
post_patch_height = height // p_h
post_patch_width = width // p_w
# Get rotary embeddings
d = self.hidden_size // self.num_attention_heads
rope_dim_list = [d - 4 * (d // 6), 2 * (d // 6), 2 * (d // 6)]
freqs_cos, freqs_sin = get_rotary_pos_embed((post_patch_num_frames, post_patch_height, post_patch_width),
self.hidden_size,
self.num_attention_heads,
rope_dim_list,
dtype=torch.float32 if current_platform.is_mps() else torch.float64,
rope_theta=10000)
freqs_cis = (freqs_cos.to(hidden_states.device).float(), freqs_sin.to(hidden_states.device).float())
hidden_states = self.patch_embedding(hidden_states)
hidden_states = hidden_states.flatten(2).transpose(1, 2)
# Shard with padding support - returns (sharded_tensor, original_seq_len)
hidden_states, original_seq_len = sequence_model_parallel_shard(hidden_states, dim=1)
current_seq_len = hidden_states.shape[1]
sp_world_size = get_sp_world_size()
padded_seq_len = current_seq_len * sp_world_size
# timestep shape: batch_size, or batch_size, seq_len (wan 2.2 ti2v)
if timestep.dim() == 2:
ts_seq_len = timestep.shape[1]
timestep = timestep.flatten() # batch_size * seq_len
else:
ts_seq_len = None
# AnyFlow dual-timestep — match timestep's flattening so embedder
# sees aligned shapes.
if r_timestep is not None and r_timestep.dim() == 2:
r_timestep = r_timestep.flatten()
temb, timestep_proj, encoder_hidden_states, encoder_hidden_states_image = self.condition_embedder(
timestep,
encoder_hidden_states,
encoder_hidden_states_image,
timestep_seq_len=ts_seq_len,
r_timestep=r_timestep)
if ts_seq_len is not None:
# batch_size, seq_len, 6, inner_dim
timestep_proj = timestep_proj.unflatten(2, (6, -1))
else:
# batch_size, 6, inner_dim
timestep_proj = timestep_proj.unflatten(1, (6, -1))
if encoder_hidden_states_image is not None:
if encoder_hidden_states is not None:
encoder_hidden_states = torch.concat([encoder_hidden_states_image, encoder_hidden_states], dim=1)
else:
encoder_hidden_states = encoder_hidden_states_image
if current_platform.is_mps() or current_platform.is_npu():
encoder_hidden_states = encoder_hidden_states.to(orig_dtype)
else:
encoder_hidden_states = encoder_hidden_states # cast to orig_dtype for MPS & NPU
assert encoder_hidden_states.dtype == orig_dtype
# 4. Transformer blocks
if torch.is_grad_enabled() and self.gradient_checkpointing:
for block in self.blocks:
hidden_states = self._gradient_checkpointing_func(block, hidden_states, encoder_hidden_states,
timestep_proj, freqs_cis, original_seq_len)
else:
for block in self.blocks:
hidden_states = block(hidden_states, encoder_hidden_states, timestep_proj, freqs_cis, original_seq_len)
# 5. Output norm, projection & unpatchify
if temb.dim() == 3:
# batch_size, seq_len, inner_dim (wan 2.2 ti2v)
shift, scale = (self.scale_shift_table.unsqueeze(0) + temb.unsqueeze(2)).chunk(2, dim=2)
shift = shift.squeeze(2)
scale = scale.squeeze(2)
else:
# batch_size, inner_dim
shift, scale = (self.scale_shift_table + temb.unsqueeze(1)).chunk(2, dim=1)
hidden_states = self.norm_out(hidden_states, shift, scale)
# Gather and unpad in one operation
hidden_states = sequence_model_parallel_all_gather_with_unpad(hidden_states, original_seq_len, dim=1)
hidden_states = self.proj_out(hidden_states)
hidden_states = hidden_states.reshape(batch_size, post_patch_num_frames, post_patch_height, post_patch_width,
p_t, p_h, p_w, -1)
hidden_states = hidden_states.permute(0, 7, 1, 4, 2, 5, 3, 6)
output = hidden_states.flatten(6, 7).flatten(4, 5).flatten(2, 3)
return output
# Entry point for model registry
EntryClass = WanTransformer3DModel