This set of tools supports unpacking and authoring FLD data files from the game Magical School Lunar! (Sega Saturn, 1997).
Aside from the commandline tool, this project also contains a Rust crate with a few helpers to let you write your own tools for working with FLD files.
On Mac:
brew install mistydemeo/lunar/fldtools
Building manually:
Clone this repo, and then
make
fldunpack FILENAME.FLD
The chunks will be extracted to a set of numbered files with filenames based on the filename from which they were extracted. By default, chunks will be extracted with the file extension "chunk"; use the --extension option to choose a custom file extension. This is useful when extracting data from the MSLM.FLD file, which contains FMVs, since other apps will expect a .cpk extension from its contents.
fldpack output.fld <input files>