If your games are already zipped, you might wonder why you should bother changing formats. Converting your archives to CHD offers three massive advantages:
: CHD files use specialized compression (like LZMA or Zlib) designed for disc images, often resulting in smaller file sizes than standard ZIP files. Direct Readability
Converting Zip files (containing disc images like BIN/CUE, ISO, or GDI) to CHD (Compressed Hunk of Data) is an excellent way to save storage space and simplify file management for retro gaming emulators like RetroArch, Duckstation, and Redream
The primary tool for this conversion is , distributed with MAME. A typical command-line workflow is as follows: Convert Zip To Chd
chdman create --input <input.zip> --output <output.chd> --type hdd
: Launch the application. You will see a modern interface with a source folder selector and an output folder selector.
: Save the all2chd.bat file from its GitHub repository into a new folder. If your games are already zipped, you might
Place chdman.exe in the same folder where you extracted your game files, or add it to your system PATH. 3. Convert Using the Command Line
Calls chdman.exe to compress those files into a .chd format. Moves the clean .chd file back to your main folder.
The vast majority of modern emulators, including RetroArch, DuckStation, PCSX2, PPSSPP, and MAME itself, have robust support for CHD files. A typical command-line workflow is as follows: chdman
What are you using (Windows, macOS, or Linux)? Which consoles or emulators are you primarily targeting? How many files are you looking to convert?
: Place a copy of chdman.exe in the same folder as the batch script.
Originally designed for MAME to store hard drive images, the CHD format has become the gold standard for disc-based media (PS1, Sega Saturn, Dreamcast, etc.) for several reasons: