Convert CDI to ISO

A program, emulator, operating system, or burning utility may require an ISO image instead of a DiscJuggler CDI file. Conversion can also make a disc image easier to mount and inspect, but retain the original CDI when it contains audio tracks, multisession data, or console-specific sectors.

What the CDI format is

CDI is the disc-image format created by Padus DiscJuggler. It describes the tracks and sectors of an optical disc and can contain data tracks, audio tracks, multisession information, raw sectors, and subchannel data. CDI files are found mainly in older DiscJuggler archives, software collections, and Dreamcast image sets.

Modern operating systems and image utilities support CDI less consistently than ISO. If the image is split across multiple files, keep every part in the same directory and use the main .cdi file as the source.

What the ISO format is

ISO usually means an image containing an ISO 9660 or compatible optical-disc filesystem. Windows, Linux, macOS, virtual-drive software, emulators, archive utilities, and disc-burning programs generally support ISO more widely than CDI.

ISO is appropriate for a standard data CD or DVD whose contents fit an ISO-compatible filesystem. It is not a complete replacement for every optical-disc image: a conventional ISO cannot preserve separate audio tracks, subchannel data, some multisession layouts, or console-specific structures. In those cases, a CUE/BIN image or the original console-specific format may be more suitable.

How to convert the image

Using PowerISO on Windows

1. Install PowerISO from its official website and open the program.
2. Choose File → Open and select the .cdi file.
3. Choose Tools → Convert or the image-conversion command shown by your version.
4. Set the destination format to ISO, choose an output path such as disc.iso, and start the conversion.
5. Mount or open the resulting ISO and verify its contents before deleting the CDI.

PowerISO is a practical graphical option, but its unregistered edition has limitations that can affect large images or some conversion operations.

Using cdi2iso

The free command-line utility cdi2iso can convert many standard DiscJuggler images on Linux and on Windows systems with a compatible executable:

cdi2iso input.cdi output.iso

Install it from a trusted distribution or project repository, then check the syntax supplied by that build:

cdi2iso --help
cdi2iso "My Disc.cdi" "My Disc.iso"

Some versions handle only particular CDI variants and data-track layouts. If the command reports unsupported tracks or creates an ISO that will not mount, use PowerISO or another desktop image utility that explicitly supports CDI; changing command-line options cannot restore data the converter does not understand.

Checking the result

• Mount the ISO or open it with an image utility and check the directory structure, expected file sizes, boot files, and application or game behavior.
• Do not compare the CDI and ISO file hashes. The containers and sector layouts differ, so their checksums normally differ even when the extracted data is identical. For a data disc, compare hashes of the extracted files instead.
• Test the ISO with the intended emulator, operating system, or hardware. A readable filesystem does not prove that boot sectors, copy-protection metadata, audio tracks, or console-specific information survived.
• For Dreamcast images and discs with audio, raw sectors, multiple sessions, or subchannel data, preserve the CDI and consider retaining a CUE/BIN or emulator-specific image rather than relying on the ISO alone.

Online conversion

There is no broadly reliable online service that accepts every CDI variant. Many generic converters do not support DiscJuggler images, impose upload limits, or return only an extracted data ISO. Local software is preferable for large, proprietary, or copyrighted images; use an online service only when its current format list explicitly names CDI, the image contains no sensitive or restricted material, and you can verify the output.