This repository contains the 4-bit affine quantized MLX conversion of Baidu's official baidu/Unlimited-OCR checkpoint. It is published for Apple Silicon inference with mlx-vlm and maintained for use by shuuul/aimd.

The model architecture, tokenizer, processor configuration, prompts, and MIT license come from the official checkpoint. Refer to the official model card and Unlimited-OCR repository for model details, capabilities, limitations, and attribution.

Conversion details

Setting	Value
Source	`baidu/Unlimited-OCR`
Tool	`mlx-vlm 0.6.8`
MLX runtime used for conversion	`mlx 0.32.0`
Output precision	`4bit`
Quantization	`affine, group size 64`
Repository size	2.29 GiB

The language-model weights use uniform affine quantization with group size 64. mlx-vlm intentionally leaves unsupported or quality-sensitive multimodal modules at higher precision, so total repository size is larger than a theoretical all-layer quantization.

Conversion command:

bash

mlx_vlm.convert \
  --hf-path baidu/Unlimited-OCR \
  --mlx-path ./Unlimited-OCR-4bit \
  --quantize --q-bits 4 --q-group-size 64 --q-mode affine

Use with AIMD

On macOS/Apple Silicon, install AIMD and run OCR directly:

bash

uv tool install --force "aimd-tool @ git+https://github.com/shuuul/aimd.git@main"
aimd scan.pdf --task ocr --model unlimited_ocr_4bit

unlimited_ocr defaults to the 4-bit repository. AIMD runs each page in Unlimited-OCR's single-image gundam mode with prompt document parsing., cropping=True, base_size=1024, image_size=640, and a sliding-window no-repeat n-gram guard. See the AIMD README for the complete runtime behavior.

Use with mlx-vlm

bash

pip install -U "mlx-vlm>=0.6.8"
python -m mlx_vlm.generate \
  --model mlx-community/Unlimited-OCR-4bit \
  --image scan.png \
  --prompt "document parsing." \
  --max-tokens 8192 \
  --temperature 0

Unlimited-OCR support first shipped in mlx-vlm 0.6.4; 0.6.8 or newer is recommended to match the conversion environment.

Available MLX weights

Precision	Repository	Size
4bit	`mlx-community/Unlimited-OCR-4bit`	2.29 GiB
6bit	`mlx-community/Unlimited-OCR-6bit`	2.98 GiB
8bit	`mlx-community/Unlimited-OCR-8bit`	3.66 GiB
bf16	`mlx-community/Unlimited-OCR-bf16`	6.22 GiB

License and attribution

The upstream checkpoint is released under the MIT license. This repository is a format conversion and does not modify the upstream model architecture or claim ownership of Baidu's model.