coreml-diffusion 0.1.0

Convert diffusion-model checkpoints (SD1.5/SDXL) to Core ML for Apple Neural Engine — framework-free, ComfyUI-independent.

coreml-diffusion

Convert diffusion-model checkpoints into Core ML .mlpackage artifacts for the Apple Neural Engine (ANE) — framework-free and independent of ComfyUI.

coreml-diffusion takes a single-file Stable Diffusion checkpoint and produces a Core ML UNet you can run on-device (macOS/iOS) or load back into ComfyUI via ComfyUI-CoreMLSuite, which depends on this package for its conversion path.

Positioning

The niche is diffusion models on the Apple Neural Engine via Core ML — inside ComfyUI and on-device. ANE is the differentiator: low-power, GPU-free, embeddable in a Swift/iOS app. This is about feasibility and power efficiency for SD1.5/SDXL on ANE, not a raw-throughput claim against desktop GPUs.

Supported today: SD1.5 and SDXL (verified). SDXL refiner and LCM convert but are not yet golden-verified (experimental). The scope is diffusion architectures generally, not Stable Diffusion specifically.

Install

uv pip install coreml-diffusion          # from PyPI (planned)
uv pip install -e .                       # from a checkout

Requires Python 3.12 and (for conversion) coremltools 9 — conversion runs on macOS; the package imports and its CLI parse on any platform.

CLI

coreml-diffusion convert \
    --ckpt path/to/model.safetensors \
    --model-version SD15 \
    --out unet.mlpackage \
    --height 512 --width 512 \
    --attn-impl SPLIT_EINSUM \
    --quantize none

Options: --batch-size, --controlnet, --lora PATH[:STRENGTH] (repeatable), --config (original-config YAML). --quantize {none,8,6,4} applies k-means weight palettization. Run coreml-diffusion convert --help for the full list.

The output .mlpackage is the deliverable: load it natively in Swift/Core ML, or through ComfyUI-CoreMLSuite.

Library

import coreml_diffusion
from coreml_diffusion import ModelVersion

coreml_diffusion.convert(
    "model.safetensors", ModelVersion.SD15, "unet.mlpackage",
    height=512, width=512, attn_impl="SPLIT_EINSUM",
)

Discovery API (list_model_versions, list_attention_impls, list_quant_modes, CONTRACT_VERSION) reports what this build can convert; the identifiers are an additive-only contract (removing/renaming one is a major bump).

License

MIT