Is it possible?

Is it possible to convert MDF/MDS files to CDI files? If so, how would you convert it?

i guess not

Remember, Google is your friend… :iagree:
…for example:

mdf and mds files are types of CD and DVD image files. Only certain software packages will read and burn these types of files.

Alcohol-Soft http://www.alcohol-soft.com/ (Trialware)
Daemon Tools http://www.daemon-tools.cc/dtcc/download.php (Freeware)

Install the software and select the mds file. The mds file basically contains the information the software needs to burn the mdf image file.

Both of these software packages will either allow you to run the image file from a simulated CD/DVD drive… or it will allow you to actually burn the image to a real CD/DVD disc.

You could mount the .mds file on a virtual drive (e,g, Daemon Tools) and re-rip from the mounted image with whatever program produces .cdi files (discjuggler?).