FBQ file format

[murla]

I've written a simple binary parser that can read file entries inside game archives (.fbq).

However, I'm stuck with compression used for actual files. lzf, lz4 and zstd are mentioned in end credits, but I had no success using them on compressed files with Linux utilities like lzf -d, lz4 -d, zstd -d. Any hint from anybody?

[Chaosvex]

Trine uses zlib for decompression (inflate). If that doesn't work, I'd check whether you've extracted the files from the FBQ archives correctly.

[JLarja]

We actually use various algorithms (sometimes none at all) to compress the files. Original Trine used zlib (I think), T2 used a mix of zlib and LZ4. I don't quite remember when zstd was added. Some of the files are also internally compressed with specific algorithms, and thus not compressed at all by FBQ.

Do note that we use the algorithms, not particular utilities. I don't know if the ones mentioned in the original post are able to work with the files in FBQ. Also note that most interesting files are in processed format. Animations and models are not compatible with any editing software, Lua scripts are compiled to byte code and so on.

-JLarja / Frozenbyte

[Kein Zantezuken]

Originally posted by JLarja:

We actually use various algorithms (sometimes none at all) to compress the files. Original Trine used zlib (I think), T2 used a mix of zlib and LZ4. I don't quite remember when zstd was added. Some of the files are also internally compressed with specific algorithms, and thus not compressed at all by FBQ.

Do note that we use the algorithms, not particular utilities. I don't know if the ones mentioned in the original post are able to work with the files in FBQ. Also note that most interesting files are in processed format. Animations and models are not compatible with any editing software, Lua scripts are compiled to byte code and so on.

-JLarja / Frozenbyte

@JLarja

Can we have an update for Trine 5 FBQ changes? I've noticed there is new compression flag, 0x04 and the method changed from `lzf` to something else, perhaps encrypted? The entropy is fairly high:
https://imgur.com/a/xdqcNWA

[JLarja]

The new compression method is Zstandard. There no encryption (in Trine 5), but I don't remember if there were some other changes. Decompression code was slightly altered to allow larger than four gigabyte FBQs.

-JLarja / Frozenbyte

[Kein Zantezuken]

Thanks!

[Kein Zantezuken]

A follow-up question if you dont mind- you guys compiled your scripts with LUA 5.3.6? The header only indicates major version.

[JLarja]

Seems to be 5.3.5.

-JLarja / Frozenbyte

[Kein Zantezuken]

Ah,. close enough, thanks again Larja!