[Feature Request] Extract ISO from chd

[BParks21]

PS2 games for instance that were converted to CHD. I would like this program to give me the option to choose what format I want to be extracted from the chd. I do not want a ps2 game to be converted from chd to bin/cue. I want them restored to their original format in case I want to use these games on real hardware. CHDMAN can already do this by default so it should be a feature in this program. We should have these options, decompress chd to bin/cue, decompress chd to iso, decompress chd to gdi.

[drakewill-CRL]

https://www.reddit.com/r/MAME/comments/rjig1q/using_chdman_to_convert_chd_back_to_iso_gives_me/iawuhs5/

MAME dev says CHDMAN can't do that, so I'm going to believe them. You should be able to burn bin/cue to disc for use on original hardware as well.

[BParks21]

https://www.reddit.com/r/MAME/comments/rjig1q/using_chdman_to_convert_chd_back_to_iso_gives_me/iawuhs5/

MAME dev says CHDMAN can't do that, so I'm going to believe them. You should be able to burn bin/cue to disc for use on original hardware as well.

Really because I do it all the time with CHDMAN using this batch file. Then I run the extracted ISO through Romcenter using a ps2 redump dat file from redump.org and it's still a confirmed valid dump and runs just fine. Also when I meant use the game on original hardware I meant run the ISO on original soft modded hardware. You can test it yourself with this batch file and chdman. It works. What this bat is doing is extracting the .cue file then automatically converting it to iso. This method works and results in the original iso file size. It's all done with chdman. This could be implemented I believe.

for %%i in (*.chd) do (
chdman extractcd -i "%%i" -o "%%~ni.cue" -ob "%%~ni.iso"
del "%%~ni.cue"
)

[BParks21]

As you can see in this screenshot. In the left file explorer window is the original iso file and in the right window is the chd extracted iso using the batch file and chdman. The far right window is the scan with 7zip to get the SHA1. The number matches the redump database. IDK what that dev is talking about or if there is some sort of misunderstanding but this batch file makes it work. You can even bulk extract chd to iso with it.

[drakewill-CRL]

So it looks like the 'happy' path works for that scenario. ISO in, ISO out. I'd suspect the other same->same pairs work too.

I wonder if the same logic applies for other formats, or if it breaks trying to convert between them. If I put BIN/CUE in, does ISO out give a valid file? And are GDI files a special format or just a renamed BIN/CUE? And can ROMSorter tell what the input format was without asking the user?

I'll have to dig into these questions. It's something worth looking at.

[BParks21]

Cool, I don't know all the technical stuff behind it. Curious to know if you can make this work. Looking forward to hearing about what you learn.