utils.py

import torch
from diffusers.loaders.lora import LoraLoaderMixin
from typing import Dict, Union
import numpy as np
import imageio

def load_lora_weights(unet, pretrained_model_name_or_path_or_dict: Union[str, Dict[str, torch.Tensor]], adapter_name = None, **kwargs):
    # if a dict is passed, copy it instead of modifying it inplace
    if isinstance(pretrained_model_name_or_path_or_dict, dict):
        pretrained_model_name_or_path_or_dict = pretrained_model_name_or_path_or_dict.copy()

    # First, ensure that the checkpoint is a compatible one and can be successfully loaded.
    state_dict, network_alphas = LoraLoaderMixin.lora_state_dict(pretrained_model_name_or_path_or_dict, **kwargs)

    # remove prefix if not removed when saved
    state_dict = {name.replace('base_model.model.', ''): param for name, param in state_dict.items()}

    is_correct_format = all("lora" in key or "dora_scale" in key for key in state_dict.keys())
    if not is_correct_format:
        raise ValueError("Invalid LoRA checkpoint.")

    low_cpu_mem_usage = True

    LoraLoaderMixin.load_lora_into_unet(
        state_dict,
        network_alphas=network_alphas,
        unet = unet,
        low_cpu_mem_usage=low_cpu_mem_usage,
        adapter_name=adapter_name,
    )

def save_video(frames, save_path, fps, quality=9):
    writer = imageio.get_writer(save_path, fps=fps, quality=quality)
    for frame in frames:
        frame = np.array(frame)
        writer.append_data(frame)
    writer.close()