Converting to CHDs for certain cores

Can I compress multi disc games to single CHD? No

Will that work with emulator? No

How can I convert back to bin+cue if I need to burn the image to disc| use command “chdman extractcd” or just run chdman and read the descriptions

Can I play FLAC tracks inside .chd file directly with audio player (preferably foobar2000) Not sure if there are available standalone players that supports directly playing from chd

FLAC compression level is used BTW (I hope 8)? dunno you have to check yourself.

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If you’d like to use multi disc games compressed into a single file, the only system I know that you can do that is PS1, the compression is called PBP and the program that you can use to do that is psx2psp 1.4.2.

Multiple CHD files compresses better than a single PBP file though and a couple games have issues with PBP compression. The m3u file becomes so simple with CHD’s. For Metal Gear Solid, all you need to do is make an .m3u file in the same folder with this written inside it:

Metal Gear Solid (USA) (Disc 1).chd
Metal Gear Solid (USA) (Disc 2).chd

Of course you need to turn everything into CHD’s first :stuck_out_tongue:

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I knew about PBP and psx2psp but I don’t like it cause it doesn’t compress CDDA tracks at all. I didn’t know that you could use m3u files like that. Thanks! That’s so convenient. If only I could listen to CDDA tracks directly from chd files that would be perfect. I’m also wondering if I there’s cmd file I could use for extracting chd files with chdman.exe to specific folder in case I need that. Same way that !Batch.cmd works.

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Everyone gets confused the first time they try to play a multi cd game. Once you know to make a m3u file it becomes extremely simple. Don’t have to rename save files or anything like that, just use retroarch hotkeys to open tray, switch to next disc, and close tray. And I hope everyone knows after making the .m3u file, that is the file you open to play the multi cd games.

Just wanted to come back and touch base on this topic. I compressed a large number of games and it made a HUGE difference. Like… MASSIVE amounts of data has been saved here. Also ran into some interesting issues as well.

First off, the problem systems:

NEC TurboGrafx-CD - Initially told by RocketLauncher that this core doesn’t support CHD. I edited the AHK file for it’s module, which fixed that problem. However, I wasn’t able to get CHD compressed games to work with the core. (Though, since then I switched to the SuperGrafx core instead as I FINALLY got it to run Arcade CD-ROM^2 games… I’ll have to try this system again.

Panasonic 3DO - Not compatible with CHD’s, far as I can tell. (4D0 Core)

Sega Dreamcast - Was never able to find out if you can just convert the CHD format from old to new, or if you’d need to extract, then reconvert again. Also, and more importantly even, if it’s worth switching from Reicast to ReDream for this process anyway.

Arcade - MAME files… I have removed this system temporarily from my system. The files backed up on my 8TB desktop drive. I just don’t care that much for these titles. Given their complex structure and the fact that most of the games worth playing have ‘acceptable’ console ports using better emulators made them more or less ‘excessive’. I’ll revisit in the future so I can clean up and move just what I need over… but good god. I don’t need this headache lol

Secondly, the systems that received compression…

Sega CD - Compressed from 70.9GB to 37.2GB

Sega Saturn - I actually added a WHOLE BUNCH of JP games to the system, but even so… Compressed from 120GB to 80.3

Sony Playstation - CHD easily made the largest impact here, went from 461GB to 266GB

Sony PS2 - Not CHD, but since we discussed compression… I compressed to CSO using the methods discussed previously. I have only compressed the DVD games however. CD still needs to be converted to ISO before compressing to CSO. That aside, this system went from 2.74TB to 1.55TB

In it’s current state I have the entirety of HyperSpin, RocketLauncher, RetroArch, and the games from every major console release (barring JP Only systems) [Every cartridge title ever, and no disc-based shovelware] ALL taking up about 2.95TB on a “4TB” portable drive (It’s really 3.63, you know how it goes) Portable also means I can play this on any PC I hook it to (I’m using it at work as I write this hahahaha)

So, barring the emergence of a wonderful Xbox emulator? I’d say I’m all set on space here now.

Thanks to everyone for their input and help. I hope this kind of gives a good template for others considering compression as well. CLEARLY it makes a massive difference.


Hey guys!

Does the pcsx_rearmed core has CHD support?

I am not able to make it work with it (I use this core as using the mednafen ones give me a black screen, probably because my crappy video card does not support vulkan).

I’m not sure if it does, I have never tried this core. I thought it was only for mobile devices like an android phone.

I do know that the Beetle_PSX_HW core also supports OpenGL, so even if you don’t have vlukan support it should function. I think it has a software mode too, but I’ve never tried that.

I personally just use the standard Beetle_PSX core. It seems to perform very well for me. Certainly better than the HW variant; though you do lose some of the ‘fancier’ functions.


/20 characters…

there is an open issue on the github page from Sept 2017. Last time I asked on discord, no one knew if it will ever get added, so unless someone add a bounty to this issue I doubt it’ll ever get added (and I tried adding it in, but my limited programming skills I failed spectacularly)

Yeah! Talked with Aorin some minutes ago and I was able to get it working (the regular mednafen core); seems my bios were no good for that specific core but worked ok with the rearmed one.

Sorry for the topic derailing.


It’s all good, I think it’s important for anyone reading to know rearmed doesn’t have CHD.

Guys do you know if there is a way/bat or command to convert from img to chd? I have some Sega CD games in img/cue/ccd/sub format.

I think you will want to convert them to bin/cue first. Easiest way to do that:

  • Mount in Daemon Tools
  • Rip the ‘disc’ to a bin/cue using IMGBurn
  • Then convert the bin/cue to CHD

If your file fails to rip in IMGBurn it’s a bad file, you’ll want to track down a different copy. At least, from my experience that’s what I’ve found while converting hundreds and hundreds of games.

Personally, even when not using CHD compression, I convert ALL CD-ROM based games to bin/cue. I find them to be very easy to work with as far as file management, and they are pretty universally accepted.

That makes sense. I made the amateur mistake of trying to mount the img file with the embedded Windows option (right-click on file > Mount) but it gave me an error, so I assumed that this type of img files cannot be mounted like CDs.

I’ll try with Daemon once I get home.

Thank you :slight_smile:

Me again… Sorry XD

I am trying to add to my game list the Marvel vs Capcom 2 and Capcom vs SNK 2 games from Dreamcast (as they are currently unplayable through MAME).

Do you guys know if there is a way to convert from CDI to CHD? (They currently weight 800MB aprox. each).

I don’t know how you’d convert CDI dumps to CHD, but you should use Redump GDIs instead, since they are clean, unmodified dumps. CDI dumps often lossy compress or sometimes remove music and/or FMVs. And GDIs are easy to convert to CHD since you can just point chdman to the GDI file like you would a CUE.

I second that, never use a CDI unless you don’t have any other option. The CDI format was used to squeeze the 1GB size Dreamcast games onto 700MB CD-Rs (or 99min CD-Rs in a few cases)

Always go for GDI then convert it to CHD on Dreamcast

Again, thank you: I did not know anything about the cdi vs gdi formats. Will do.

Using Hyperspin with Reicast on a Shield TV…I’m trying to get my Dreamcast gdi files to chd files. Easy enough, but I’m on a Mac. I’ve tried gditochd through Windows Parallels and it won’t work because of the virtual path names that Parallels assigns and it can’t find the paths for the files it needs, no matter where I place them. Anyone know of a work around? I looked all over for a similar program for the Mac , but couldn’t find one. I even tried using an external HDD to house the files while converting, but Parallels still has issues with gditochd and the paths…Frustrating having all these gdi files and no way to convert them. I would leave them as is, but Reicast is very picky about gdi vs. chd files and performance on the Shield TV…