Problems extracting *.JAS file

[1st]

I stumbled across a *.JAS file and I can't find a way to extract images stored in there. It's one of the Renpy VNs that has all it's images stored in such file.

I tried Paint Shop Pro but failed. Found some info about some Cheetah3D software but it's for Macs only and I'm stuck with PC.

Any idea how to handle such file on PC? I'm out of ideas...

 

[baloneysammich]

I've never heard of a renpy game that stored its images in a .jas file. Seems more likely it's a resource file the dev packaged with the game, or even an extension that doesn't match the actual filetype.

What's the game? If the file isn't too big, can you attach or upload it somewhere?

 

[1st]

I've never heard of a renpy game that stored its images in a .jas file. Seems more likely it's a resource file the dev packaged with the game, or even an extension that doesn't match the actual filetype.

What's the game? If the file isn't too big, can you attach or upload it somewhere?

This is what I originally thought. Furthermore, online extractors that SHOULD handle .JAS files returned errors (unknown file structure etc.).
I tried changing it's extension name to .rpa and treat it with RPAExtractor but it didn't help. In a last attempt I tried a few archive extractors but those failed too.

The game is "Jason":
https://f95zone.to/threads/jason-v0-5-coeurdecochon.95537/

 

[gnadudu]

The dev of the game changed the header of the archive from RPA-3.0 to JAS-X.0X. Copy the jas file you want to extract somewhere else, then use a hexeditor to change the header (I personally use

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) back to RPA-3.0 (there's a whitespace at the end) and then use

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to extract the files...
Before changing the header:

After changing the header:


Edit: I added code to rpatool which automatically allows to unpack *.jas files, the edited file can be found in the attachment. (It also allows the extract pea files from BigCityPleasures where the archive format was changed even heavier than this one... ^^)
I uploaded the extracted files for those who are too lazy...

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^^