RAW Image Infrastructure & Utilities

mu-image is a cross-platform collection of high-performance tools for software engineers, astrophotographers, and time-lapse editors to process, convert, and render raw image files.

The repository contains two packages:

• muimg: A Python library and CLI engine for Adobe DNG manipulation, rendering, metadata handling, and multi-threaded batch processing.
• mu-dng-converter: A cross-platform desktop GUI application built on muimg and PyWebView for batch-converting raw image folders, time-lapse sequences, and astronomical data.

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Primary Use Cases

• DNG support in your app: a source-available python package to add DNG support to your project (no restrictions except for large companies)
• DNG to video time-lapse assembly: Stitch folders of raw DNG frames directly into MP4/H.264 video clips. Suited for allsky camera sequences and day-to-night astrophotography arrays.
• Astronomical FITS to DNG conversion: Convert scientific .fits files into compliant .dng raw images for editing in Adobe Photoshop, Lightroom, or Camera Raw.
• Batch image transcoding: Mass-convert raw sequences to TIFF (8-bit/16-bit), JPEG, and JPEG XL (JXL) with multi-core parallel processing.

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Key Technical Features

Advanced RAW Rendering Pipeline (muimg)

• Demosaicing: Multiple algorithms — DNGSDK_BILINEAR, VNG, RCD, and OPENCV_EA.
• Opcode & color correction: Full DNG rendering pipeline including linearization, opcodes, color correction matrices, and custom tone curves.
• Native OS acceleration: On macOS, choose between the built-in pipeline renderer and the hardware-accelerated Apple Core Image renderer.
• XMP metadata: Some support for embedded XMP. Automatically applies Temperature, Tint, Exposure, custom curves, and radial distortion corrections as configured in your RAW editor.
• cli: feature-rich cli to render, transcode, and inspect DNG files

Desktop GUI Application (mu-dng-converter)

DNG to Image & Video Transcoding

• Full rendering control: Override white balance (presets or custom Kelvin/tint), adjust exposure, change output bit depth, or apply a resolution scale (0.125x–1.0x) for quick previews.
• Multi-threaded video encoding: Dedicated video mode with direct control over codec, resolution, frame rate, and CRF for lightweight MP4 output from raw frames.

Astronomical FITS to DNG

• Histogram-based auto exposure: Analyses the image histogram to estimate a black level (1st percentile) and an exposure shift (targeting ~6% brightness), so FITS files open at a usable baseline in standard RAW editors.
• AVM XMP metadata mapping: Maps WCS data (CRVAL, CDELT), object names, filter parameters, and telescope details from FITS headers into Astronomy Visualization Metadata (AVM) XMP tags embedded in the output DNG.
• Fast-load optimization: Embeds JPEG previews and image pyramids in the exported DNG for instant browsing.

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Supported Platforms

• Windows (x86_64)
• macOS (Intel & Apple Silicon)
• Linux (Ubuntu, Debian, Fedora)
• Raspberry Pi (ARM64 — suitable for low-power allsky camera rigs and remote observatories)

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Getting Started

Desktop app (macOS, Windows, Linux): Download a pre-built binary from the mu-dng-converter releases page. No Python installation required. See mu-dng-converter/README.md for GUI usage and feature details.

Python library: See muimg/README.md for installation, API reference, and CLI usage.

Release history: See CHANGELOG.md.