Wan2.1/wan/image2video.py
2025-12-15 19:15:22 +08:00

391 lines
14 KiB
Python

# Copyright 2024-2025 The Alibaba Wan Team Authors. All rights reserved.
import gc
import logging
import math
import os
import random
import sys
import types
from time import perf_counter
from contextlib import contextmanager
from functools import partial
import numpy as np
import torch
import torch.cuda.amp as amp
from torch.cuda import empty_cache, synchronize
import torch.distributed as dist
import torchvision.transforms.functional as TF
from tqdm import tqdm
try:
import torch_musa
import torch_musa.core.amp as amp
from torch_musa.core.memory import empty_cache
from torch_musa.core.device import synchronize
torch.backends.mudnn.allow_tf32 = True
except ModuleNotFoundError:
torch_musa = None
from wan.distributed.fsdp import shard_model
from wan.modules.clip import CLIPModel
from wan.modules.model import WanModel
from wan.modules.t5 import T5EncoderModel
from wan.modules.vae import WanVAE
from wan.utils.fm_solvers import (
FlowDPMSolverMultistepScheduler,
get_sampling_sigmas,
retrieve_timesteps,
)
from wan.utils.fm_solvers_unipc import FlowUniPCMultistepScheduler
from wan.utils.platform import get_device
from wan.utils.memory_format import convert_conv3d_weight_memory_format
class WanI2V:
def __init__(
self,
config,
checkpoint_dir,
device_id=0,
rank=0,
t5_fsdp=False,
dit_fsdp=False,
use_usp=False,
t5_cpu=False,
init_on_cpu=True,
profiler=None,
):
r"""
Initializes the image-to-video generation model components.
Args:
config (EasyDict):
Object containing model parameters initialized from config.py
checkpoint_dir (`str`):
Path to directory containing model checkpoints
device_id (`int`, *optional*, defaults to 0):
Id of target GPU device
rank (`int`, *optional*, defaults to 0):
Process rank for distributed training
t5_fsdp (`bool`, *optional*, defaults to False):
Enable FSDP sharding for T5 model
dit_fsdp (`bool`, *optional*, defaults to False):
Enable FSDP sharding for DiT model
use_usp (`bool`, *optional*, defaults to False):
Enable distribution strategy of USP.
t5_cpu (`bool`, *optional*, defaults to False):
Whether to place T5 model on CPU. Only works without t5_fsdp.
init_on_cpu (`bool`, *optional*, defaults to True):
Enable initializing Transformer Model on CPU. Only works without FSDP or USP.
"""
self.device = get_device(device_id)
self.config = config
self.rank = rank
self.use_usp = use_usp
self.t5_cpu = t5_cpu
self.num_train_timesteps = config.num_train_timesteps
self.param_dtype = config.param_dtype
shard_fn = partial(shard_model, device_id=device_id)
self.text_encoder = T5EncoderModel(
text_len=config.text_len,
dtype=config.t5_dtype,
device=torch.device('cpu'),
checkpoint_path=os.path.join(checkpoint_dir, config.t5_checkpoint),
tokenizer_path=os.path.join(checkpoint_dir, config.t5_tokenizer),
shard_fn=shard_fn if t5_fsdp else None,
)
self.vae_stride = config.vae_stride
self.patch_size = config.patch_size
self.vae = WanVAE(
vae_pth=os.path.join(checkpoint_dir, config.vae_checkpoint),
device=self.device)
convert_conv3d_weight_memory_format(self.vae.model, memory_format=torch.channels_last_3d)
self.clip = CLIPModel(
dtype=config.clip_dtype,
device=self.device,
checkpoint_path=os.path.join(checkpoint_dir,
config.clip_checkpoint),
tokenizer_path=os.path.join(checkpoint_dir, config.clip_tokenizer))
logging.info(f"Creating WanModel from {checkpoint_dir}")
self.model = WanModel.from_pretrained(checkpoint_dir)
self.model.eval().requires_grad_(False)
if t5_fsdp or dit_fsdp or use_usp:
init_on_cpu = False
if use_usp:
from xfuser.core.distributed import get_sequence_parallel_world_size
from .distributed.xdit_context_parallel import (
usp_attn_forward,
usp_dit_forward,
)
for block in self.model.blocks:
block.self_attn.forward = types.MethodType(
usp_attn_forward, block.self_attn)
self.model.forward = types.MethodType(usp_dit_forward, self.model)
self.sp_size = get_sequence_parallel_world_size()
else:
self.sp_size = 1
if dist.is_initialized():
# dist.barrier()
pass
if dit_fsdp:
self.model = shard_fn(self.model)
else:
if not init_on_cpu:
self.model.to(self.device)
self.sample_neg_prompt = config.sample_neg_prompt
self.profiler = profiler
def generate(self,
input_prompt,
img,
max_area=720 * 1280,
frame_num=81,
shift=5.0,
sample_solver='unipc',
sampling_steps=40,
guide_scale=5.0,
n_prompt="",
seed=-1,
offload_model=True):
r"""
Generates video frames from input image and text prompt using diffusion process.
Args:
input_prompt (`str`):
Text prompt for content generation.
img (PIL.Image.Image):
Input image tensor. Shape: [3, H, W]
max_area (`int`, *optional*, defaults to 720*1280):
Maximum pixel area for latent space calculation. Controls video resolution scaling
frame_num (`int`, *optional*, defaults to 81):
How many frames to sample from a video. The number should be 4n+1
shift (`float`, *optional*, defaults to 5.0):
Noise schedule shift parameter. Affects temporal dynamics
[NOTE]: If you want to generate a 480p video, it is recommended to set the shift value to 3.0.
sample_solver (`str`, *optional*, defaults to 'unipc'):
Solver used to sample the video.
sampling_steps (`int`, *optional*, defaults to 40):
Number of diffusion sampling steps. Higher values improve quality but slow generation
guide_scale (`float`, *optional*, defaults 5.0):
Classifier-free guidance scale. Controls prompt adherence vs. creativity
n_prompt (`str`, *optional*, defaults to ""):
Negative prompt for content exclusion. If not given, use `config.sample_neg_prompt`
seed (`int`, *optional*, defaults to -1):
Random seed for noise generation. If -1, use random seed
offload_model (`bool`, *optional*, defaults to True):
If True, offloads models to CPU during generation to save VRAM
Returns:
torch.Tensor:
Generated video frames tensor. Dimensions: (C, N H, W) where:
- C: Color channels (3 for RGB)
- N: Number of frames (81)
- H: Frame height (from max_area)
- W: Frame width from max_area)
"""
start_time = 0.0
end_time = 0.0
if self.rank == 0:
start_time = perf_counter()
img = TF.to_tensor(img).sub_(0.5).div_(0.5).to(self.device)
F = frame_num
h, w = img.shape[1:]
aspect_ratio = h / w
lat_h = round(
np.sqrt(max_area * aspect_ratio) // self.vae_stride[1] //
self.patch_size[1] * self.patch_size[1])
lat_w = round(
np.sqrt(max_area / aspect_ratio) // self.vae_stride[2] //
self.patch_size[2] * self.patch_size[2])
h = lat_h * self.vae_stride[1]
w = lat_w * self.vae_stride[2]
max_seq_len = ((F - 1) // self.vae_stride[0] + 1) * lat_h * lat_w // (
self.patch_size[1] * self.patch_size[2])
max_seq_len = int(math.ceil(max_seq_len / self.sp_size)) * self.sp_size
seed = seed if seed >= 0 else random.randint(0, sys.maxsize)
seed_g = torch.Generator(device=self.device)
seed_g.manual_seed(seed)
noise = torch.randn(
16, (F - 1) // 4 + 1,
lat_h,
lat_w,
dtype=torch.float32,
generator=seed_g,
device=self.device)
msk = torch.ones(1, F, lat_h, lat_w, device=self.device)
msk[:, 1:] = 0
msk = torch.concat([
torch.repeat_interleave(msk[:, 0:1], repeats=4, dim=1), msk[:, 1:]
],
dim=1)
msk = msk.view(1, msk.shape[1] // 4, 4, lat_h, lat_w)
msk = msk.transpose(1, 2)[0]
if n_prompt == "":
n_prompt = self.sample_neg_prompt
# preprocess
if not self.t5_cpu:
self.text_encoder.model.to(self.device)
context = self.text_encoder([input_prompt], self.device)
context_null = self.text_encoder([n_prompt], self.device)
if offload_model:
self.text_encoder.model.cpu()
else:
context = self.text_encoder([input_prompt], torch.device('cpu'))
context_null = self.text_encoder([n_prompt], torch.device('cpu'))
context = [t.to(self.device) for t in context]
context_null = [t.to(self.device) for t in context_null]
self.clip.model.to(self.device)
clip_context = self.clip.visual([img[:, None, :, :]])
if offload_model:
self.clip.model.cpu()
y = self.vae.encode([
torch.concat([
torch.nn.functional.interpolate(
img[None].cpu(), size=(h, w), mode='bicubic').transpose(
0, 1),
torch.zeros(3, F - 1, h, w)
],
dim=1).to(self.device)
])[0]
y = torch.concat([msk, y])
if self.rank == 0:
end_time = perf_counter()
logging.info(f"[preprocess and VAE encode] Elapsed time: {end_time - start_time:.2f} seconds")
@contextmanager
def noop_no_sync():
yield
no_sync = getattr(self.model, 'no_sync', noop_no_sync)
# evaluation mode
with amp.autocast(dtype=self.param_dtype), torch.no_grad(), no_sync():
if sample_solver == 'unipc':
sample_scheduler = FlowUniPCMultistepScheduler(
num_train_timesteps=self.num_train_timesteps,
shift=1,
use_dynamic_shifting=False)
sample_scheduler.set_timesteps(
sampling_steps, device=self.device, shift=shift)
timesteps = sample_scheduler.timesteps
elif sample_solver == 'dpm++':
sample_scheduler = FlowDPMSolverMultistepScheduler(
num_train_timesteps=self.num_train_timesteps,
shift=1,
use_dynamic_shifting=False)
sampling_sigmas = get_sampling_sigmas(sampling_steps, shift)
timesteps, _ = retrieve_timesteps(
sample_scheduler,
device=self.device,
sigmas=sampling_sigmas)
else:
raise NotImplementedError("Unsupported solver.")
# sample videos
latent = noise
arg_c = {
'context': [context[0]],
'clip_fea': clip_context,
'seq_len': max_seq_len,
'y': [y],
}
arg_null = {
'context': context_null,
'clip_fea': clip_context,
'seq_len': max_seq_len,
'y': [y],
}
if offload_model:
empty_cache()
if self.rank == 0:
start_time = perf_counter()
self.model.to(self.device)
for _, t in enumerate(tqdm(timesteps)):
if self.profiler and self.rank == 0:
self.profiler.step()
latent_model_input = [latent.to(self.device)]
timestep = [t]
timestep = torch.stack(timestep).to(self.device)
noise_pred_cond = self.model(
latent_model_input, t=timestep, **arg_c)[0].to(
torch.device('cpu') if offload_model else self.device)
if offload_model:
empty_cache()
noise_pred_uncond = self.model(
latent_model_input, t=timestep, **arg_null)[0].to(
torch.device('cpu') if offload_model else self.device)
if offload_model:
empty_cache()
noise_pred = noise_pred_uncond + guide_scale * (
noise_pred_cond - noise_pred_uncond)
latent = latent.to(
torch.device('cpu') if offload_model else self.device)
temp_x0 = sample_scheduler.step(
noise_pred.unsqueeze(0),
t,
latent.unsqueeze(0),
return_dict=False,
generator=seed_g)[0]
latent = temp_x0.squeeze(0)
if self.rank == 0:
end_time = perf_counter()
logging.info(f"[sampling time steps] Elapsed time: {end_time - start_time:.2f} seconds")
x0 = [latent.to(self.device)]
del latent_model_input, timestep
if offload_model:
self.model.cpu()
empty_cache()
if self.rank == 0:
start_time = perf_counter()
videos = self.vae.decode(x0)
end_time = perf_counter()
logging.info(f"[VAE decoding] Elapsed time: {end_time - start_time:.2f} seconds")
del noise, latent
del sample_scheduler
if offload_model:
gc.collect()
synchronize()
if dist.is_initialized():
# dist.barrier()
pass
return videos[0] if self.rank == 0 else None