MiniMax-H3 Fun ControlNet-Union, pruned, W4A8

W4A8 quantization of the MiniMax-H3 Fun ControlNet-Union model patch for ComfyUI.

Quantization

• Format: asym_w4a8_int8 (4-bit asymmetric weights, int8 activations), ConvRot rotation with group size 256, weight group size 16.
• Applied to the 20 2D projection layers of the 5 control blocks. Norms, embeddings, biases and the AdaLN basis stay in bf16/fp32.
• Calibration-free (reference format). Quantization metadata is stored in the safetensors header (_quantization_metadata, comfy_wxa8), the layout ComfyUI reads natively.

Usage (ComfyUI)

1. Put the file in models/model_patches/.
2. Load it with ModelPatchLoader, apply with MiniMaxH3FunControlNetApply (see the bundled template video_minimax_h3_fun_controlnet_union).
3. Requires ComfyUI 0.35.0 or newer. This file carries native quantization metadata; the Comfy-Org int8_convrot build uses the legacy scale-tensor format and needs Comfy-Org/ComfyUI#16221 on 0.35.0.

Notes

• Loads and builds all 5 control blocks. Output quality relative to the bf16 and int8_convrot builds has not been measured.
• License follows the source model (MiniMax-H3 Community License Agreement).