Upscaler Models

mold supports Real-ESRGAN super-resolution models for image upscaling. These models enhance image resolution by 2x or 4x using neural networks trained on image restoration tasks.

Model List

RRDBNet Architecture (High Quality)

The Residual-in-Residual Dense Block Network uses deep convolutional layers with dense connections for maximum quality.

Model	Scale	Params	Size (FP16)	Description
real-esrgan-x4plus:fp16	4x	16.7M	32 MB	General-purpose, best quality
real-esrgan-x4plus:fp32	4x	16.7M	64 MB	Same model, FP32 precision
real-esrgan-x2plus:fp16	2x	16.7M	32 MB	2x upscale, best quality
real-esrgan-x4plus-anime:fp16	4x	4.5M	8.5 MB	Anime/illustration optimized (6 blocks)

SRVGGNetCompact Architecture (Fast)

A lightweight linear chain architecture optimized for speed. Uses significantly less compute than RRDBNet while maintaining good quality.

Model	Scale	Params	Size	Description
real-esrgan-anime-v3:fp32	4x	0.6M	2.4 MB	Fast anime/video upscaler

Architecture Details

RRDBNet

Input (3, H, W)
  ↓ Conv2d(3 → 64)
  ↓ [RRDB block × 23] — each: 3 × ResidualDenseBlock (5 convs with dense connections)
  ↓ Conv2d(64 → 64)
  ↓ Upsample 2x (nearest) + Conv2d
  ↓ Upsample 2x (nearest) + Conv2d   ← only for 4x models
  ↓ Conv2d(64 → 64) + LeakyReLU
  ↓ Conv2d(64 → 3)
Output (3, H×scale, W×scale)

SRVGGNetCompact

Input (3, H, W)
  ↓ Conv2d(3 → 64)
  ↓ [PReLU + Conv2d(64 → 64)] × N
  ↓ PReLU
  ↓ Conv2d(64 → 3×scale²)
  ↓ PixelShuffle(scale)
Output (3, H×scale, W×scale)

Downloading

# Pull the default high-quality upscaler
mold pull real-esrgan-x4plus:fp16

# Pull the fast compact upscaler
mold pull real-esrgan-anime-v3:fp32

# List all available models including upscalers
mold list

HuggingFace Sources

All upscaler models are sourced from trusted HuggingFace repositories:

• RRDBNet models: Comfy-Org/Real-ESRGAN_repackaged (safetensors)
• x2plus model: hlky/RealESRGAN_x2plus (safetensors)

Comparison

Use Case	Recommended Model	Why
Photo upscaling	real-esrgan-x4plus:fp16	Best detail preservation
Anime/manga	real-esrgan-x4plus-anime:fp16	Trained on anime data
Batch processing	real-esrgan-anime-v3:fp32	5-10x faster
Video frames	real-esrgan-anime-v3:fp32	Smallest, fastest
Subtle enhancement	real-esrgan-x2plus:fp16	2x is less aggressive