SeedVR2 Tiling Upscaler

A ComfyUI custom node for memory-efficient image upscaling using SeedVR2 models with advanced tiling and detail-preserving stitching.

WARNING: This is not magic - although it sometimes may seem that way. It will alter details and it might even change things you don't like. But in my testing the outputs are more convincing than any other detailer / upscaler processes I tested so far. Personally, I use it to refine Flux / ... outputs and enhance skin detail (or any detail) for further, more natural looking training datasets. Upscaling for print use is also one way to use this.

The stitching code is not optimal. I am trying to solve this, but "blurring" is not a good idea. I need to look into this more.

Example upscales

Features

• Advanced Multi-Band Blending: Frequency-separated processing eliminates seams while preserving detail
• Content-Aware Stitching: Adaptive blending based on local image structure and edge strength
• Edge-Preserving Smoothing: Bilateral filtering reduces artifacts without destroying fine details
• Memory Optimized: Prevents OOM errors using configurable tile-based upscaling
• SeedVR2 Integration: Works with all SeedVR2 model variants (3B/7B, FP16/FP8, Sharp versions)
• Advanced Tiling: Linear and Chess tiling strategies with configurable overlap

How It Works

1. Input image is divided into overlapping tiles
2. Each tile is upscaled using SeedVR2 to a fixed resolution
3. Upscaled tiles are resized to their final target dimensions
4. Advanced Multi-Band Stitching:
   • Zero-blur mode: Frequency-separated blending preserves fine details while eliminating seams
   • Content-aware mode: Structure-adaptive blending with edge-preserving smoothing
   • Bilateral filtering: Reduces artifacts without destroying texture details

A personal suggestion

I also included example workflows (in the 'workflows' directory). Use the the advanced workflow for even better outputs. This one will do a first pass with the regular SeedVR2 node and then pass that output to a second pass, which does the tiled upscaling. The advanced workflow uses one of my other nodes from the "moonpack" (ProportionalDimension, https://github.com/moonwhaler/comfyui-moonpack).

But why?

A little "trick" is to downscale the image (yes, we degrade quality at first) and add static noise (which provides variance when upscaling). After that the upscale is able to "create" finer details. The downside is that the original image is altered more. You can play around with this using the provided "switches" in the advanced workflow (less downscale, less new details, but more true to the original image - add more noise to get more variance in finer parts of the image). If you have text in an image and want to preserve it, you should go for a very low downscale factor!

In my tests the results were sometimes exceptional, sometimes "meh", depending on what I wanted to get (illustrations, portraits etc.). This also depends on the seed. I suggest using a random one to get slightly altered outputs - or a fixed one to compare changes.

Installation

Prerequisites

• ComfyUI installed and working
• SeedVR2 models and nodes installed in ComfyUI

Install the Node

1. Clone this repository to your ComfyUI custom nodes directory:

cd ComfyUI/custom_nodes/
git clone https://github.com/moonwhaler/UltimateResupscaler.git

2. Install dependencies (outside of ComfyUI):

IMPORTANT: The requirements must be installed in the same Python environment that ComfyUI uses. This is typically a virtual environment (venv) or conda environment.

For venv users:

# Activate your ComfyUI virtual environment first
source /path/to/your/comfyui/venv/bin/activate  # Linux/Mac
# OR
/path/to/your/comfyui/venv/Scripts/activate  # Windows

# Then install requirements
cd UltimateResupscaler
pip install -r requirements.txt

For conda users:

# Activate your ComfyUI conda environment first
conda activate your-comfyui-environment

# Then install requirements
cd UltimateResupscaler
pip install -r requirements.txt

For portable ComfyUI installations:

# Use the Python executable from your ComfyUI installation
cd UltimateResupscaler
/path/to/ComfyUI/python_embeded/python.exe -m pip install -r requirements.txt  # Windows
# OR
/path/to/ComfyUI/python/bin/python -m pip install -r requirements.txt  # Linux/Mac

Note: Do NOT install these requirements in your system Python or a different environment, as ComfyUI will not be able to find them.

3. Restart ComfyUI

The node will appear in the image/upscaling category as "SeedVR2 Tiling Upscaler".

Requirements

System Requirements

• Python 3.10+
• CUDA-capable GPU (recommended)
• Sufficient RAM/VRAM for chosen tile upscale resolution

Dependencies

• torch>=1.9.0
• torchvision>=0.10.0
• numpy>=1.21.0
• Pillow>=8.0.0
• scipy>=1.7.0
• scikit-image>=0.19.0 (optional, for advanced blending)
• opencv-python>=4.5.0 (optional, for edge-preserving smoothing)
• SeedVR2 node (installed separately)

Usage

1. Add the "SeedVR2 Tiling Upscaler" node to your ComfyUI workflow
2. Connect your input image
3. Select your desired SeedVR2 model
4. Configure parameters
5. Run the workflow

Parameters

Core Settings

• model: SeedVR2 model to use for upscaling
• seed: Random seed for reproducible results
• new_resolution: Target resolution for the longest side of the output image
• preserve_vram: Enable VRAM optimization in SeedVR2

Memory Management

• tile_upscale_resolution: Maximum resolution for individual tile upscaling
  • Lower values = less memory usage, faster processing
  • Higher values = better quality, more memory usage
  • Recommended: 1024-2048 depending on VRAM

Tiling Configuration

• tile_width/height: Size of each tile in pixels (default: 512x512)
• tile_padding: Overlap between tiles in pixels (default: 32)
• tiling_strategy:
  • Linear: Process tiles row by row
  • Chess: Process tiles in checkerboard pattern for better blending

Detail Preservation

• mask_blur: Blending control for tile edges (default: 0)
  • 0: Zero-blur mode - Maximum detail preservation through pixel averaging
  • 1-3: Smart minimal blur - Hides seams while preserving details
  • 4+: Traditional blur - Smoother blending with some detail loss

Recommended Settings

Maximum Detail Preservation

• mask_blur: 0 (multi-band frequency separation)
• tile_padding: 64 pixels (more overlap for better blending)
• tile_upscale_resolution: Highest your VRAM allows
• anti_aliasing_strength: 0.2 (subtle smoothing)

Balanced Quality & Speed

• mask_blur: 2 (content-aware blending with bilateral filtering)
• tile_padding: 32 pixels
• tile_upscale_resolution: 1024-1536
• anti_aliasing_strength: 0.1

Fast Processing

• mask_blur: 1 (lightweight edge-preserving blend)
• tile_padding: 16 pixels
• tiling_strategy: Linear
• anti_aliasing_strength: 0.0

Troubleshooting

OOM Errors

• Reduce tile_upscale_resolution
• Enable preserve_vram
• Reduce tile_width and tile_height
• Use the "SeedVR2 BlockSwap Config" (from the original SeedVR2 nodes) and attach it to the "block_swap_config" input of the Tiling Upscaler node. Set the "blocks_to_swap" value until you won't get any OOMs anymore. You need RAM for that in return!

Visible Seams

• New solution: The advanced multi-band blending should eliminate most seams
• Try mask_blur: 1 or 2 for content-aware blending
• Increase tile_padding to 64+ pixels for more overlap
• Use Chess tiling strategy for better distribution

Detail Loss

• Use mask_blur: 0 for multi-band frequency separation (preserves most detail)
• Ensure adequate tile_padding (64+ pixels recommended)
• Increase tile_upscale_resolution if possible
• Lower anti_aliasing_strength or set to 0

Slow Processing

• Use Linear tiling
• mask_blur: 1 (lightweight processing)
• Reduce tile_padding if seams aren't visible
• Set anti_aliasing_strength: 0

Known issues

The progressbar in ComfyUI is showing "???" when the tiling upscaler is working. This is not an error per-se, but a nuisance.

License

MIT No Attribution

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Credits

• Partly based on the Ultimate SD Upscale methodology and adapted to the SeedVR2 process
• Adapted for SeedVR2 models with detail preservation focus
• Built for ComfyUI ecosystem
• Example image (https://www.flickr.com/photos/160246067@N08/44726249090, public domain license) by TLC Jonhson (https://www.flickr.com/photos/160246067@N08/)