Hacking ROM Hack Project [ACWW] LZ77 compressed texts, have you already seen it ?

[Pikario]

Hello!

I'm currently trying to extract all the texts from Animal Crossing Wild World, I used Tinke to browse the ROM content and I found the texts under the folder "script", all of them are .bmg files. I extracted them with Tinke and openned them with my text editor (Kate). I can see they are texts but the encoding seems incorrect, I tried all the ones available in the editor without success.
I noticed all the files begin with this characters : "LZ77÷", so they are LZ77 compressed? I know the principles of the algorithm, I tried some decompressor but it didn't work.
Here is a screenshot of a file in Kate:

Have you already encountered similar files? I attach a bmg (I changed the extension to txt) to this post.

 

[SolatoroboHacking]

Yes, you need to run that through an LZ77 decompressor. These tools are excellent, and will work with every variant of LZ77 compression used by the DS. Try running it through these tools until you get a decompressed file that gives no errors and/or has no garbled text.

Edit: It also looks as though these files don't quite use standard headers, so you might have to mess around with a hex editor a bit. The header is probably supposed to be 0x10 followed by the uncompressed file size in three bytes. That information is probably in there somewhere, you just might need to dig a bit to find it.

 

[Pikario]

Thank you for your help and information! I've managed to make my own decompressor for Wild World files, based on the tools you mentioned.
Here is the source code, if it can help someone in the future: Pikari0/ACWW_texts_decompressor on GitHub (it seems I can't post full links as a new user)