Initial release: ComfyUI nodes for STAR video super-resolution

Two-node package wrapping the STAR (ICCV 2025) diffusion-based video
upscaling pipeline:

- STAR Model Loader: loads UNet+ControlNet, OpenCLIP text encoder, and
  temporal VAE with auto-download from HuggingFace
- STAR Video Super-Resolution: runs the full diffusion pipeline with
  configurable upscale factor, guidance, solver mode, chunking, and
  color correction

Includes three VRAM offload modes (disabled/model/aggressive) to
support GPUs from 12GB to 40GB+.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-02-14 23:20:27 +01:00
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import os
import sys
import torch
import folder_paths
import comfy.model_management as mm
# Register the "star" model folder so users can drop .pt weights there.
star_model_dir = os.path.join(folder_paths.models_dir, "star")
os.makedirs(star_model_dir, exist_ok=True)
folder_paths.folder_names_and_paths["star"] = (
[star_model_dir],
folder_paths.supported_pt_extensions,
)
# Put the cloned STAR repo on sys.path so its internal imports work.
STAR_REPO = os.path.join(os.path.dirname(os.path.realpath(__file__)), "STAR")
if STAR_REPO not in sys.path:
sys.path.insert(0, STAR_REPO)
# Known models on HuggingFace that can be auto-downloaded.
HF_REPO = "SherryX/STAR"
HF_MODELS = {
"light_deg.pt": "I2VGen-XL-based/light_deg.pt",
"heavy_deg.pt": "I2VGen-XL-based/heavy_deg.pt",
}
def _get_model_list():
"""Return the union of files already on disk + known downloadable models."""
on_disk = set(folder_paths.get_filename_list("star"))
available = set(HF_MODELS.keys())
return sorted(on_disk | available)
def _ensure_model(model_name: str) -> str:
"""Return the local path to model_name, downloading from HF if needed."""
local = folder_paths.get_full_path("star", model_name)
if local is not None:
return local
if model_name not in HF_MODELS:
raise FileNotFoundError(
f"Model '{model_name}' not found in {star_model_dir} and is not a known downloadable model."
)
from huggingface_hub import hf_hub_download
print(f"[STAR] Downloading {model_name} from HuggingFace ({HF_REPO})...")
path = hf_hub_download(
repo_id=HF_REPO,
filename=HF_MODELS[model_name],
local_dir=star_model_dir,
)
# hf_hub_download may place the file in a subdirectory; symlink into the
# star folder root so folder_paths can find it next time.
dest = os.path.join(star_model_dir, model_name)
if not os.path.exists(dest):
os.symlink(path, dest)
return dest
class STARModelLoader:
@classmethod
def INPUT_TYPES(cls):
return {
"required": {
"model_name": (_get_model_list(), {
"tooltip": "STAR checkpoint to load. light_deg for mildly degraded video, heavy_deg for heavily degraded video. Auto-downloaded from HuggingFace on first use.",
}),
"precision": (["fp16", "bf16", "fp32"], {
"default": "fp16",
"tooltip": "Weight precision. fp16 is recommended (fastest, lowest VRAM). bf16 for newer GPUs. fp32 for maximum quality at 2x VRAM cost.",
}),
"offload": (["disabled", "model", "aggressive"], {
"default": "disabled",
"tooltip": "disabled: all on GPU (~39GB). model: swap UNet/VAE/CLIP to CPU when idle (~16GB). aggressive: model offload + single-frame VAE decode (~12GB).",
}),
}
}
RETURN_TYPES = ("STAR_MODEL",)
RETURN_NAMES = ("star_model",)
FUNCTION = "load_model"
CATEGORY = "STAR"
DESCRIPTION = "Loads the STAR video super-resolution model (UNet+ControlNet, OpenCLIP text encoder, temporal VAE). All components are auto-downloaded on first use."
def load_model(self, model_name, precision, offload="disabled"):
device = mm.get_torch_device()
dtype_map = {"fp16": torch.float16, "bf16": torch.bfloat16, "fp32": torch.float32}
dtype = dtype_map[precision]
# Where to park models when not in use.
keep_on = device if offload == "disabled" else "cpu"
model_path = _ensure_model(model_name)
# ---- Text encoder (OpenCLIP ViT-H-14) ----
from video_to_video.modules.embedder import FrozenOpenCLIPEmbedder
text_encoder = FrozenOpenCLIPEmbedder(
device=device, pretrained="laion2b_s32b_b79k"
)
text_encoder.model.to(device)
# Pre-compute the negative prompt embedding used during sampling.
from video_to_video.utils.config import cfg
negative_y = text_encoder(cfg.negative_prompt).detach()
# Park text encoder after pre-computing embeddings.
text_encoder.model.to(keep_on)
# ---- UNet + ControlNet ----
from video_to_video.modules.unet_v2v import ControlledV2VUNet
generator = ControlledV2VUNet()
load_dict = torch.load(model_path, map_location="cpu", weights_only=False)
if "state_dict" in load_dict:
load_dict = load_dict["state_dict"]
generator.load_state_dict(load_dict, strict=False)
del load_dict
generator = generator.to(device=keep_on, dtype=dtype)
generator.eval()
# ---- Noise schedule + diffusion helper ----
from video_to_video.diffusion.schedules_sdedit import noise_schedule
from video_to_video.diffusion.diffusion_sdedit import GaussianDiffusion
sigmas = noise_schedule(
schedule="logsnr_cosine_interp",
n=1000,
zero_terminal_snr=True,
scale_min=2.0,
scale_max=4.0,
)
diffusion = GaussianDiffusion(sigmas=sigmas)
# ---- Temporal VAE (from HuggingFace diffusers) ----
from diffusers import AutoencoderKLTemporalDecoder
vae = AutoencoderKLTemporalDecoder.from_pretrained(
"stabilityai/stable-video-diffusion-img2vid",
subfolder="vae",
variant="fp16",
)
vae.eval()
vae.requires_grad_(False)
vae.to(keep_on)
torch.cuda.empty_cache()
star_model = {
"text_encoder": text_encoder,
"generator": generator,
"diffusion": diffusion,
"vae": vae,
"negative_y": negative_y,
"device": device,
"dtype": dtype,
"offload": offload,
}
return (star_model,)
class STARVideoSuperResolution:
@classmethod
def INPUT_TYPES(cls):
return {
"required": {
"star_model": ("STAR_MODEL", {
"tooltip": "Connect from STAR Model Loader.",
}),
"images": ("IMAGE", {
"tooltip": "Input video frames (IMAGE batch). Can come from LoadImage, VHS LoadVideo, etc.",
}),
"upscale": ("INT", {
"default": 4, "min": 1, "max": 8,
"tooltip": "Upscale factor applied to the input resolution. 4x is the default. Higher values need more VRAM.",
}),
"steps": ("INT", {
"default": 15, "min": 1, "max": 100,
"tooltip": "Number of denoising steps. Ignored in 'fast' solver mode (hardcoded 15). More steps = better quality but slower.",
}),
"guide_scale": ("FLOAT", {
"default": 7.5, "min": 1.0, "max": 20.0, "step": 0.5,
"tooltip": "Classifier-free guidance scale. Higher values follow the prompt more strongly. 7.5 is a good default.",
}),
"prompt": ("STRING", {
"default": "", "multiline": True,
"tooltip": "Text prompt describing the desired output. Leave empty to use STAR's built-in quality prompt.",
}),
"solver_mode": (["fast", "normal"], {
"default": "fast",
"tooltip": "fast: optimized 15-step schedule (4 coarse + 11 fine). normal: uniform schedule using the steps parameter.",
}),
"max_chunk_len": ("INT", {
"default": 32, "min": 4, "max": 128,
"tooltip": "Max frames processed at once. Lower values reduce VRAM usage for long videos. Chunks overlap by 50%.",
}),
"seed": ("INT", {
"default": 0, "min": 0, "max": 0xFFFFFFFFFFFFFFFF,
"tooltip": "Random seed for reproducible results.",
}),
"color_fix": (["adain", "wavelet", "none"], {
"default": "adain",
"tooltip": "Post-processing color correction. adain: match color stats from input. wavelet: preserve input low-frequency color. none: no correction.",
}),
}
}
RETURN_TYPES = ("IMAGE",)
RETURN_NAMES = ("images",)
FUNCTION = "upscale_video"
CATEGORY = "STAR"
DESCRIPTION = "Upscale video frames using STAR diffusion-based super-resolution."
def upscale_video(
self,
star_model,
images,
upscale,
steps,
guide_scale,
prompt,
solver_mode,
max_chunk_len,
seed,
color_fix,
):
from .star_pipeline import run_star_inference
result = run_star_inference(
star_model=star_model,
images=images,
upscale=upscale,
steps=steps,
guide_scale=guide_scale,
prompt=prompt,
solver_mode=solver_mode,
max_chunk_len=max_chunk_len,
seed=seed,
color_fix=color_fix,
)
return (result,)
NODE_CLASS_MAPPINGS = {
"STARModelLoader": STARModelLoader,
"STARVideoSuperResolution": STARVideoSuperResolution,
}
NODE_DISPLAY_NAME_MAPPINGS = {
"STARModelLoader": "STAR Model Loader",
"STARVideoSuperResolution": "STAR Video Super-Resolution",
}