Rom Bin Cue Chd Conversion

BIN/CUE to CHD Conversion

Use this skill when converting CD-based disc images between BIN/CUE and CHD format. Prefer CHD for storage and emulator workflows when the target emulator supports it, and preserve the original BIN/CUE set until the CHD has been validated.

What this skill does

• Converts disc-based ROM sets from .cue + .bin to .chd
• Extracts CHD files back to .cue + .bin
• Verifies CHD integrity
• Handles multi-track CD images correctly when the .cue sheet is accurate
• Gives commands for macOS and Windows

Use the right tool

• chdman createcd for BIN/CUE -> CHD
• chdman extractcd for CHD -> BIN/CUE
• chdman info for format and compression details
• chdman verify for CHD integrity checks

Do not use archive tools or ad-hoc compression to make CHD files. The CHD format needs chdman so the sector layout and metadata are preserved correctly.

Before you convert

1. Find the .cue file for the game.
2. Confirm every referenced .bin file exists and the names match exactly.
3. Keep the source files untouched until the CHD has been verified.
4. Preserve the original basename unless the user asks for a different naming scheme.
5. For multi-disc games, convert each disc separately and keep the disc number in the filename.

If there is only a loose .bin file and no valid .cue, stop and ask for the cue sheet or a proper disc manifest. createcd is meant to read the cue sheet and the tracks it references.

macOS workflow

Install chdman

Prefer the system package that provides chdman:

• Homebrew: brew install rom-tools
• If the user already has MAME installed, use the chdman binary from that installation instead of reinstalling

Confirm availability:

• which chdman
• chdman --version

Convert BIN/CUE to CHD

chdman createcd -i "Game Name.cue" -o "Game Name.chd"

Useful options:

• -f overwrite an existing output file
• -v print verbose progress
• -np <count> limit or increase worker threads
• -c <compression list> only when you have a reason to change the default compression

For most CD images, the default compression choices are fine. Change them only if the user specifically wants different tradeoffs.

Verify the CHD

chdman info -i "Game Name.chd"
chdman verify -i "Game Name.chd"

info shows the compression, hunk size, size, and hashes. verify checks the file integrity.

Extract CHD back to BIN/CUE

chdman extractcd -i "Game Name.chd" -o "Game Name.cue" -ob "Game Name.bin"

If the user wants one binary file per track instead of one combined BIN, add -sb:

chdman extractcd -i "Game Name.chd" -o "Game Name.cue" -sb

Windows workflow

Install chdman

Install MAME or a rom-tools package that includes chdman.exe, then make sure it is on PATH.

Verify it in PowerShell:

Get-Command chdman.exe
chdman.exe --version

If chdman.exe is not on PATH, call it with a full path.

Convert BIN/CUE to CHD

PowerShell:

& "C:\MAME\chdman.exe" createcd -i "Game Name.cue" -o "Game Name.chd"

Command Prompt:

chdman.exe createcd -i "Game Name.cue" -o "Game Name.chd"

Verify the CHD

& "C:\MAME\chdman.exe" info -i "Game Name.chd"
& "C:\MAME\chdman.exe" verify -i "Game Name.chd"

Extract CHD back to BIN/CUE

& "C:\MAME\chdman.exe" extractcd -i "Game Name.chd" -o "Game Name.cue" -ob "Game Name.bin"

Use -sb when the user wants one BIN per track:

& "C:\MAME\chdman.exe" extractcd -i "Game Name.chd" -o "Game Name.cue" -sb

Multi-disc and emulator notes

• Convert each disc separately.
• Keep disc numbers in the filenames, such as Game Name (Disc 1).chd.
• If the user wants convenient disc swapping, create an .m3u playlist that points at the per-disc CHD files.
• For RetroArch, DuckStation, and similar emulators, CHD is usually the cleaner long-term format for CD-based games.

Troubleshooting

• If chdman cannot find tracks, the .cue file probably has a filename mismatch. Fix the cue or rename the referenced files so they match exactly.
• If the command fails because the output already exists, rerun with -f only when overwriting is intentional.
• If the user is on Windows and the command is not found, use the full path to chdman.exe or fix PATH before trying again.
• If the conversion succeeds but the emulator does not load the CHD, verify the CHD with chdman info and chdman verify, then keep the original BIN/CUE as a fallback.

Good handoff behavior

• Explain the conversion result in plain language.
• Tell the user where the CHD file was written.
• Mention whether the source BIN/CUE was left untouched.
• If extraction was requested, tell the user whether the output is a single BIN or split BIN tracks.