If you are serious about Wii U emulation and want to maintain a large library without needing multiple terabytes of storage, is an essential tool. It bridges the gap between massive raw data and playable, efficient, compressed files.
is a command-line tool developed by the Cemu team used to compress or decompress Wii U disc images. It specifically handles the conversion between uncompressed .WUD files and compressed .WUX files. Core Functionality
Since there is no formal research paper, you can find the technical implementation and usage guides at these sources:
Removes "junk" or duplicate sectors (empty space) from the disc image while keeping 100% of the actual game data intact. WUX to WUD Decompression: WudCompress
The tool addresses the large, fixed file size of standard Wii U disc dumps—which are typically ~23GB regardless of the actual data content—by removing the "padding" or empty space.
The gaming community has rapidly adopted WudCompress—hence the "Wud" naming convention (originally derived from "Wide Universal Distribution"). Emulation enthusiasts use WudCompress to store disc images (ISO, BIN, CSO). A standard PlayStation 2 ISO (4.7GB) compresses down to using WudCompress, with zero performance hit during emulation when using the WudMount virtual drive.
: Shrinks uncompressed, bloated 23.3 GB files down to their actual data footprint (often reducing file sizes by up to 90%). If you are serious about Wii U emulation
For standard office files (DOCX, PDF, XLSX), WudCompress achieves an average reduction of —compared to 58% for conventional ZIP. For log files, databases, and CSV exports, the WudCompress "Text Shredder" mode frequently reaches 90% compression ratios .
: It can reduce massive game files (often 25GB raw) down to as little as 2GB–3GB by removing empty "padding" data. Compatibility : Compressed files can be opened and played directly in the Cemu emulator without needing to be decompressed first. Simple Operation
Keeps critical game encryption hashes intact, ensuring complete stability when linking graphic packs or shaders inside emulator directory menus. It specifically handles the conversion between uncompressed
The .wux format is a compressed, stripped-down alternative designed specifically to mitigate storage waste. WudCompress acts as the bridge between these two formats, packing .wud archives into highly efficient .wux files while preserving the complete cryptographic integrity of the original dump. How WudCompress Works Under the Hood
While originally created for Windows, WudCompress is cross-platform. The source code is written in C++ and is available on GitHub, including a mirrored repository from the cemu-project.
Raw Wii U disc dumps are typically 23.3 GB , regardless of how much actual data the game contains, because they include "dummy data" to fill the disc. WudCompress removes this empty space to save storage.