chdman extractcd -i game.chd -o extracted.cue For hard drives:

chdman copy -i old_v4.chd -o new_v5.chd -c zstd (zstd = Zstandard compression; others: lzma, flac, huffman) Assume you have a folder of BIN/CUE PS1 games.

For decades, MAME (Multiple Arcade Machine Emulator) focused on arcade PCBs. However, as the project evolved into a comprehensive emulation umbrella for computers, consoles, and arcade machines, a new problem emerged: hard drive images, CD-ROMs, and laser discs .

Storing raw, uncompressed disc images (like BIN/CUE, ISO, or GDI) for PlayStation, Sega Saturn, or arcade hard drives consumes terabytes of space. Enter (Compressed Hunks of Data MANager). What is CHDMAN? CHDMAN is a command-line tool bundled with MAME. It converts raw disk images into the CHD (Compressed Hunks of Data) format. This format applies lossless compression to disc sectors, often reducing file sizes by 40–60% without losing any data.