What's new

Converting Dreamcast Game Dumps to nullDC/Demul Compatible CDI Format


New member
Hi gang!

Emulation newbie here - hello! I've been wanting to add a Dreamcast games library to my arcade cabinet for a long time, and after recently managing to purchase a broadband adapter from eBay, it seems my dream (apologies for the pun - couldn't resist!) is coming to life.

I've successfully dumped virtually all of my legally owned Dreamcast games (as well as my own Dreamcast bios). I'm really happy that it was easier than expected, and I can now play them on nullDC and Demul without issue by loading the disc.gdi file that my Dreamcast dumps produced. Hurrah!

The is one pretty huge problem, however: They're all in a format which closely resembles something like this:

  • track01.bin
  • track02.raw
  • track03.bin
  • disc.gdi

My arcade cabinet set-up uses a system where all game dumps are stored in the same folder (which I'm happy to stick with and would rather not change), and because all dumps use a virtually identical naming structure, it's impossible to store all dumps in one folder without them overwriting each other. Ideally, what I would love is to have them compressed into a single file format (7zip format would be an absolute last resort as it takes a while for my arcade software to extract the contents each time, and this is more for my son than me) such as cdi, and also renamed to reflect the game title, ie: Crazy Taxi 2.cdi for example.

I've scoured every article and resource that Google has thrown up, but I'm still no closer. My best lead so far has been to use BootDreams, and it seemed promising at first, but the cdi files it generates do not seem to get past the Sega logo screen for either nullDC or Demul. I'm at my wit's end. My son loves it when I'm able to add new games to the arcade cabinet, and he's a huge fan of Sega's classic games, so it would be great to be able to get all this set up for him (and me, too, of course!)

tl;dr: Need to convert my Dreamcast game dumps to nullDC/Demul compatible cdi format.

Anywho, that's all! Hope you guys can help point me in the right direction. I'm certain that there's an easy solution that I'm missing!

Cheers for any and all help! :)


Demul developer
as for Demul - I recommend to use CHDv5 format, this is how all GD dumps I have stored.
you need to:
- grab latest MAME package at http://www.mamedev.org/release.html
- take chdman.exe from there and put to some GDI dump folder, then enter following in command line
chdman createcd -i disc.gdi -o some_name.chd

after some time you'll get compressed disk image. by default special CD/GD targeted LZMA(7z) and FLAC codecs will be used, so resulting CHD will be even smaller than 7zip or Rar compressed with maximum rate.

so, now you can use this chd image(s) directly in emulator with gdrCHD plugin. of course on-the-fly decompressing have some CPU load penalties, but it is low and in most cases not notable.
Last edited: