GameCube save format

[Seregon]

I am currently developing a save converter tool, where the user should be able to switch between GameCube regions and different save formats with the click of a button. I have researched and compared file footers and headers, but haven't quite yet figured out how they are built. Does anybody know how the save file structure is built on the different file formats of GCI, GCS and SAV?

[Jack Frost]

YAGCD has next to nothing on them, so they might be game specific or something? At least the headers and stuff are part of the Memory Card and not the save itself.

[JosJuice]

According to the code I can find in Dolphin, this is how GCS and SAV differ from GCI:

1. SAV has an extra 0x80 byte header and GCS has an extra 0x110 byte header, whereas GCI has none

2. A little bit of extra conversion has to be performed as described by this function: https://github.com/dolphin-emu/dolphin/blob/beeb6754d2c653c05ab5ed7def0abbfa8fb0e9c4/Source/Core/Core/HW/GCMemcard/GCMemcard.cpp#L1017 (also see the comment at https://github.com/dolphin-emu/dolphin/blob/beeb6754d2c653c05ab5ed7def0abbfa8fb0e9c4/Source/Core/Core/HW/GCMemcard/GCMemcard.h#L389-L390)

And in case you're not familiar with converting the region of a save file: For some games, you just have to edit the fourth byte of the GCI file (or the equivalent byte in one of the other file formats). For some other games, you have to do some non-trivial work that is specific to the game.

[Seregon]

(09-01-2018, 01:54 AM)JosJuice Wrote: According to the code I can find in Dolphin, this is how GCS and SAV differ from GCI:

1. SAV has an extra 0x80 byte header and GCS has an extra 0x110 byte header, whereas GCI has none

2. A little bit of extra conversion has to be performed as described by this function: https://github.com/dolphin-emu/dolphin/blob/beeb6754d2c653c05ab5ed7def0abbfa8fb0e9c4/Source/Core/Core/HW/GCMemcard/GCMemcard.cpp#L1017 (also see the comment at https://github.com/dolphin-emu/dolphin/blob/beeb6754d2c653c05ab5ed7def0abbfa8fb0e9c4/Source/Core/Core/HW/GCMemcard/GCMemcard.h#L389-L390)

And in case you're not familiar with converting the region of a save file: For some games, you just have to edit the fourth byte of the GCI file (or the equivalent byte in one of the other file formats). For some other games, you have to do some non-trivial work that is specific to the game.

Thanks! That's the perfect place to start