Real-ESRGAN x2plus, optimized Core ML package for WaifuFinder
Model weights copyright (c) 2021 Xintao Wang. BSD 3-Clause; see LICENSE.

Original weights: https://github.com/xinntao/Real-ESRGAN (RealESRGAN_x2plus.pth)
Reference architecture: https://github.com/XPixelGroup/BasicSR (revision 8d56e3a);
the architecture source and its Apache-2.0 licence are included as
BasicSR-LICENSE.

WaifuFinder converts these weights to Core ML offline. The conversion fuses the
network's first convolution into the following upsampling stage, expresses the
network's input and output shapes as enumerated Core ML shapes, and records the
native validation result in the model's metadata. The weights themselves are
unchanged: manifest.json pins the SHA-256 of the original checkpoint and of the
architecture definition.

This package replaces the pre-converted RealESRGAN_x2plus_522_fp16 model from
hanxiao/real-esrgan-coreml that earlier builds downloaded. WaifuFinder's version
adds validated 256 and 384 pixel inputs, so small tiles spend far less work than
padding to 522, and it is the only variant with a recorded original-model
parity result. See validation.json.

Inference uses only native Swift and Core ML. Conversion used coremltools and
PyTorch offline.