chdman is the compression tool included with MAME. You can download the latest MAME binaries from the official site, or find a standalone chdman.exe (Windows). For Mac/Linux, you can compile it or use Homebrew ( brew install chdman ).

In this guide, we will explain what CHD files are, why they are better than BIN/CUE or ISO, how to use them on modern emulators and handhelds (like the Steam Deck or Retroid Pocket), and how to convert your existing library.