generate.py

# Copyright 2024-2025 The Alibaba Wan Team Authors. All rights reserved.
import argparse
import logging
import os
import sys
import warnings
from datetime import datetime

warnings.filterwarnings('ignore')

import random

import torch
import torch.distributed as dist
from PIL import Image

import wan
from wan.configs import MAX_AREA_CONFIGS, SIZE_CONFIGS, SUPPORTED_SIZES, WAN_CONFIGS
from wan.distributed.util import init_distributed_group
from wan.utils.prompt_extend import DashScopePromptExpander, QwenPromptExpander
from wan.utils.utils import cache_video, str2bool

EXAMPLE_PROMPT = {
    "t2v-A14B": {
        "prompt":
            "Two anthropomorphic cats in comfy boxing gear and bright gloves fight intensely on a spotlighted stage.",
    },
    "i2v-A14B": {
        "prompt":
            "Summer beach vacation style, a white cat wearing sunglasses sits on a surfboard. The fluffy-furred feline gazes directly at the camera with a relaxed expression. Blurred beach scenery forms the background featuring crystal-clear waters, distant green hills, and a blue sky dotted with white clouds. The cat assumes a naturally relaxed posture, as if savoring the sea breeze and warm sunlight. A close-up shot highlights the feline's intricate details and the refreshing atmosphere of the seaside.",
        "image":
            "examples/i2v_input.JPG",
    },
    "ti2v-5B": {
        "prompt":
            "Two anthropomorphic cats in comfy boxing gear and bright gloves fight intensely on a spotlighted stage.",
    },
}


def _validate_args(args):
    # Basic check
    assert args.ckpt_dir is not None, "Please specify the checkpoint directory."
    assert args.task in WAN_CONFIGS, f"Unsupport task: {args.task}"
    assert args.task in EXAMPLE_PROMPT, f"Unsupport task: {args.task}"

    if args.prompt is None:
        args.prompt = EXAMPLE_PROMPT[args.task]["prompt"]
    if args.image is None and "image" in EXAMPLE_PROMPT[args.task]:
        args.image = EXAMPLE_PROMPT[args.task]["image"]

    if args.task == "i2v-A14B":
        assert args.image is not None, "Please specify the image path for i2v."

    cfg = WAN_CONFIGS[args.task]

    if args.sample_steps is None:
        args.sample_steps = cfg.sample_steps

    if args.sample_shift is None:
        args.sample_shift = cfg.sample_shift

    if args.sample_guide_scale is None:
        args.sample_guide_scale = cfg.sample_guide_scale

    if args.frame_num is None:
        args.frame_num = cfg.frame_num

    args.base_seed = args.base_seed if args.base_seed >= 0 else random.randint(
        0, sys.maxsize)
    # Size check
    assert args.size in SUPPORTED_SIZES[
        args.
        task], f"Unsupport size {args.size} for task {args.task}, supported sizes are: {', '.join(SUPPORTED_SIZES[args.task])}"


def _parse_args():
    parser = argparse.ArgumentParser(
        description="Generate a image or video from a text prompt or image using Wan"
    )
    parser.add_argument(
        "--task",
        type=str,
        default="t2v-A14B",
        choices=list(WAN_CONFIGS.keys()),
        help="The task to run.")
    parser.add_argument(
        "--size",
        type=str,
        default="1280*720",
        choices=list(SIZE_CONFIGS.keys()),
        help="The area (width*height) of the generated video. For the I2V task, the aspect ratio of the output video will follow that of the input image."
    )
    parser.add_argument(
        "--frame_num",
        type=int,
        default=None,
        help="How many frames of video are generated. The number should be 4n+1"
    )
    parser.add_argument(
        "--ckpt_dir",
        type=str,
        default=None,
        help="The path to the checkpoint directory.")
    parser.add_argument(
        "--offload_model",
        type=str2bool,
        default=None,
        help="Whether to offload the model to CPU after each model forward, reducing GPU memory usage."
    )
    parser.add_argument(
        "--ulysses_size",
        type=int,
        default=1,
        help="The size of the ulysses parallelism in DiT.")
    parser.add_argument(
        "--t5_fsdp",
        action="store_true",
        default=False,
        help="Whether to use FSDP for T5.")
    parser.add_argument(
        "--t5_cpu",
        action="store_true",
        default=False,
        help="Whether to place T5 model on CPU.")
    parser.add_argument(
        "--dit_fsdp",
        action="store_true",
        default=False,
        help="Whether to use FSDP for DiT.")
    parser.add_argument(
        "--save_file",
        type=str,
        default=None,
        help="The file to save the generated video to.")
    parser.add_argument(
        "--prompt",
        type=str,
        default=None,
        help="The prompt to generate the video from.")
    parser.add_argument(
        "--use_prompt_extend",
        action="store_true",
        default=False,
        help="Whether to use prompt extend.")
    parser.add_argument(
        "--prompt_extend_method",
        type=str,
        default="local_qwen",
        choices=["dashscope", "local_qwen"],
        help="The prompt extend method to use.")
    parser.add_argument(
        "--prompt_extend_model",
        type=str,
        default=None,
        help="The prompt extend model to use.")
    parser.add_argument(
        "--prompt_extend_target_lang",
        type=str,
        default="zh",
        choices=["zh", "en"],
        help="The target language of prompt extend.")
    parser.add_argument(
        "--base_seed",
        type=int,
        default=-1,
        help="The seed to use for generating the video.")
    parser.add_argument(
        "--image",
        type=str,
        default=None,
        help="The image to generate the video from.")
    parser.add_argument(
        "--sample_solver",
        type=str,
        default='unipc',
        choices=['unipc', 'dpm++'],
        help="The solver used to sample.")
    parser.add_argument(
        "--sample_steps", type=int, default=None, help="The sampling steps.")
    parser.add_argument(
        "--sample_shift",
        type=float,
        default=None,
        help="Sampling shift factor for flow matching schedulers.")
    parser.add_argument(
        "--sample_guide_scale",
        type=float,
        default=None,
        help="Classifier free guidance scale.")
    parser.add_argument(
        "--convert_model_dtype",
        action="store_true",
        default=False,
        help="Whether to convert model paramerters dtype.")

    args = parser.parse_args()

    _validate_args(args)

    return args


def _init_logging(rank):
    # logging
    if rank == 0:
        # set format
        logging.basicConfig(
            level=logging.INFO,
            format="[%(asctime)s] %(levelname)s: %(message)s",
            handlers=[logging.StreamHandler(stream=sys.stdout)])
    else:
        logging.basicConfig(level=logging.ERROR)


def generate(args):
    rank = int(os.getenv("RANK", 0))
    world_size = int(os.getenv("WORLD_SIZE", 1))
    local_rank = int(os.getenv("LOCAL_RANK", 0))
    device = local_rank
    _init_logging(rank)

    if args.offload_model is None:
        args.offload_model = False if world_size > 1 else True
        logging.info(
            f"offload_model is not specified, set to {args.offload_model}.")
    if world_size > 1:
        torch.cuda.set_device(local_rank)
        dist.init_process_group(
            backend="nccl",
            init_method="env://",
            rank=rank,
            world_size=world_size)
    else:
        assert not (
            args.t5_fsdp or args.dit_fsdp
        ), f"t5_fsdp and dit_fsdp are not supported in non-distributed environments."
        assert not (
            args.ulysses_size > 1
        ), f"sequence parallel are not supported in non-distributed environments."

    if args.ulysses_size > 1:
        assert args.ulysses_size == world_size, f"The number of ulysses_size should be equal to the world size."
        init_distributed_group()

    if args.use_prompt_extend:
        if args.prompt_extend_method == "dashscope":
            prompt_expander = DashScopePromptExpander(
                model_name=args.prompt_extend_model,
                task=args.task,
                is_vl=args.image is not None)
        elif args.prompt_extend_method == "local_qwen":
            prompt_expander = QwenPromptExpander(
                model_name=args.prompt_extend_model,
                task=args.task,
                is_vl=args.image is not None,
                device=rank)
        else:
            raise NotImplementedError(
                f"Unsupport prompt_extend_method: {args.prompt_extend_method}")

    cfg = WAN_CONFIGS[args.task]
    if args.ulysses_size > 1:
        assert cfg.num_heads % args.ulysses_size == 0, f"`{cfg.num_heads=}` cannot be divided evenly by `{args.ulysses_size=}`."

    logging.info(f"Generation job args: {args}")
    logging.info(f"Generation model config: {cfg}")

    if dist.is_initialized():
        base_seed = [args.base_seed] if rank == 0 else [None]
        dist.broadcast_object_list(base_seed, src=0)
        args.base_seed = base_seed[0]

    logging.info(f"Input prompt: {args.prompt}")
    img = None
    if args.image is not None:
        img = Image.open(args.image).convert("RGB")
        logging.info(f"Input image: {args.image}")

    # prompt extend
    if args.use_prompt_extend:
        logging.info("Extending prompt ...")
        if rank == 0:
            prompt_output = prompt_expander(
                args.prompt,
                image=img,
                tar_lang=args.prompt_extend_target_lang,
                seed=args.base_seed)
            if prompt_output.status == False:
                logging.info(
                    f"Extending prompt failed: {prompt_output.message}")
                logging.info("Falling back to original prompt.")
                input_prompt = args.prompt
            else:
                input_prompt = prompt_output.prompt
            input_prompt = [input_prompt]
        else:
            input_prompt = [None]
        if dist.is_initialized():
            dist.broadcast_object_list(input_prompt, src=0)
        args.prompt = input_prompt[0]
        logging.info(f"Extended prompt: {args.prompt}")

    if "t2v" in args.task:
        logging.info("Creating WanT2V pipeline.")
        wan_t2v = wan.WanT2V(
            config=cfg,
            checkpoint_dir=args.ckpt_dir,
            device_id=device,
            rank=rank,
            t5_fsdp=args.t5_fsdp,
            dit_fsdp=args.dit_fsdp,
            use_sp=(args.ulysses_size > 1),
            t5_cpu=args.t5_cpu,
            convert_model_dtype=args.convert_model_dtype,
        )

        logging.info(f"Generating video ...")
        video = wan_t2v.generate(
            args.prompt,
            size=SIZE_CONFIGS[args.size],
            frame_num=args.frame_num,
            shift=args.sample_shift,
            sample_solver=args.sample_solver,
            sampling_steps=args.sample_steps,
            guide_scale=args.sample_guide_scale,
            seed=args.base_seed,
            offload_model=args.offload_model)
    elif "ti2v" in args.task:
        logging.info("Creating WanTI2V pipeline.")
        wan_ti2v = wan.WanTI2V(
            config=cfg,
            checkpoint_dir=args.ckpt_dir,
            device_id=device,
            rank=rank,
            t5_fsdp=args.t5_fsdp,
            dit_fsdp=args.dit_fsdp,
            use_sp=(args.ulysses_size > 1),
            t5_cpu=args.t5_cpu,
            convert_model_dtype=args.convert_model_dtype,
        )

        logging.info(f"Generating video ...")
        video = wan_ti2v.generate(
            args.prompt,
            img=img,
            size=SIZE_CONFIGS[args.size],
            max_area=MAX_AREA_CONFIGS[args.size],
            frame_num=args.frame_num,
            shift=args.sample_shift,
            sample_solver=args.sample_solver,
            sampling_steps=args.sample_steps,
            guide_scale=args.sample_guide_scale,
            seed=args.base_seed,
            offload_model=args.offload_model)
    else:
        logging.info("Creating WanI2V pipeline.")
        wan_i2v = wan.WanI2V(
            config=cfg,
            checkpoint_dir=args.ckpt_dir,
            device_id=device,
            rank=rank,
            t5_fsdp=args.t5_fsdp,
            dit_fsdp=args.dit_fsdp,
            use_sp=(args.ulysses_size > 1),
            t5_cpu=args.t5_cpu,
            convert_model_dtype=args.convert_model_dtype,
        )

        logging.info("Generating video ...")
        video = wan_i2v.generate(
            args.prompt,
            img,
            max_area=MAX_AREA_CONFIGS[args.size],
            frame_num=args.frame_num,
            shift=args.sample_shift,
            sample_solver=args.sample_solver,
            sampling_steps=args.sample_steps,
            guide_scale=args.sample_guide_scale,
            seed=args.base_seed,
            offload_model=args.offload_model)

    if rank == 0:
        if args.save_file is None:
            formatted_time = datetime.now().strftime("%Y%m%d_%H%M%S")
            formatted_prompt = args.prompt.replace(" ", "_").replace("/",
                                                                     "_")[:50]
            suffix = '.mp4'
            args.save_file = f"{args.task}_{args.size.replace('*','x') if sys.platform=='win32' else args.size}_{args.ulysses_size}_{formatted_prompt}_{formatted_time}" + suffix

        logging.info(f"Saving generated video to {args.save_file}")
        cache_video(
            tensor=video[None],
            save_file=args.save_file,
            fps=cfg.sample_fps,
            nrow=1,
            normalize=True,
            value_range=(-1, 1))
    del video

    torch.cuda.synchronize()
    if dist.is_initialized():
        dist.barrier()
        dist.destroy_process_group()

    logging.info("Finished.")


if __name__ == "__main__":
    args = _parse_args()
    generate(args)