This set of tools allows you to extract and replace the music from the Steam release of Akai Katana. I was inspired to make it because I love the FM arranged soundtrack from the Nin2 Jump/Akai Katana CD, but there's no way to actually use it in game. If there won't be an official one, why not make my own?
Getting the tool
Prebuilt copies of the tool can be found in the "releases" tab in GitHub. You should be able to just download and run the ZIP file or tarball.
How to use
Akai Katana's music is in a file called Stream.bin within the game folder. To start, copy it into the folder with these tools.
The akextract tool is used to extract the music from Stream.bin. After extracting, you'll have a set of 40 .wav files with all the music from all three versions of the soundtrack. The tracklist.txt file in the documents folder explains which file is which song.
To replace songs with new ones, you'll need to reencode the new file in Microsoft's ADPCM format. Doing this requires Microsoft's commandline tool AdpcmEncode.exe. The game won't accept normal WAV files, and it won't accept ADPCM files made with any other tool (like FFmpeg).
To let the music loop properly, you can use a tool such as Wavosaur; instructions for editing loop points are here. AdpcmEncode.exe will use the loop points embedded into the uncompressed WAV files. If you're using the FM arrange from the Nin2 Jump/Akai Katana CD, I've included a set of loop points in the loop_points.txt file in the documents folder.
Once you're done preparing your music, place your new ADPCM WAV files in a folder with any of the original music you're keeping. Your new folder should still have 40 WAV files with the same numbered names as the original ones. Once you're ready, you can run the akrepack tool to repackage your files into a new Stream.bin. For example, if your new soundtrack is in a folder called in, you would run akrepack --input in. This will produce a new file called Stream.bin.repacked. Just replace the file in Akai Katana's game folder with this new file, and you're ready to go.
Notes
Although my generated files have loop points in place, I've had some trouble getting the game to use them. If anyone figures out what's wrong and could lend a hand, I'd appreciate it!
Shin mode features one extra stage, stage 5, and the music used for that stage is missing in the arcade soundtrack. When you play Shin with the original soundtrack, stage 5 will use the song from the 360 arranged soundtrack.
Building from source
These tools are written in Rust, and can be built using standard Rust tools. As long as you have the Rust compiler installed, you just need to run cargo build.
Contributing
Contributions are always welcome! Please open issues if you run into any issues, and pull requests are always a big help.