chdman

MAME Compressed Hunks of Data manager

TLDR

Display CHD file information

$ chdman info -i [path/to/image.chd]

Verify CHD file integrity

$ chdman verify -i [path/to/image.chd]

Create CHD from CD image (bin/cue)

$ chdman createcd -i [path/to/image.cue] -o [path/to/output.chd]

Create CHD from raw hard disk image

$ chdman createhd -i [path/to/image.img] -o [path/to/output.chd]

Extract CD image from CHD

$ chdman extractcd -i [path/to/image.chd] -o [path/to/output.cue]

Extract raw hard disk image from CHD

$ chdman extracthd -i [path/to/image.chd] -o [path/to/output.img]

Copy CHD with different compression

$ chdman copy -i [path/to/input.chd] -o [path/to/output.chd] -c [lzma,zlib,huff,flac]

SYNOPSIS

chdman command [-i input] [-o output] [-c compression] [options...]

chdman is the MAME Compressed Hunks of Data (CHD) manager. CHD is a lossless compression format designed for disk images used by MAME and other emulators, supporting hard disks, CD-ROMs, LaserDiscs, and GD-ROMs.The format provides efficient compression while maintaining perfect data integrity, making it ideal for archiving game media. CHD supports delta compression against parent images to reduce storage for similar versions.

PARAMETERS

info

Display CHD header information

verify

Validate MD5/SHA1 checksums

createcd

Create CHD from CD image (cue/bin, toc/bin, gdi)

createhd

Create CHD from raw hard disk image

createraw

Create CHD from raw data file

createld

Create CHD from LaserDisc image

extractcd

Extract CD image from CHD

extracthd

Extract hard disk image from CHD

copy

Copy CHD with optional recompression

-i file

Input file

-o file

Output file

-c algorithms

Compression: none, or up to four comma-separated algorithms (default: lzma,zlib,huff,flac)

--outputparent file

Create delta CHD storing only differences from parent

INSTALL

sudo apt install mame-tools

sudo dnf install mame-tools

sudo pacman -S mame-tools

sudo zypper install mame-tools

nix profile install nixpkgs#mame-tools

CAVEATS

Hunk size must be between 16 bytes and 1 MiB. CHD format is supported by emulators for 3DO, Dreamcast, PlayStation, Saturn, Mega CD, Neo-Geo CD, PC Engine CD, and other platforms.

HISTORY

CHD was developed as part of the MAME (Multiple Arcade Machine Emulator) project to provide efficient, lossless compression for disk images while preserving exact data for accurate emulation.

RESOURCES

Source code · Documentation