Hi all, I'm hoping this is an easy one. Does anyone know what compression algorithm is used by The Lost Vikings? Here is a sample compressed file . After decompression it should be in XMI format. I don't have a decompressed version of it, but here is another file in XMI format which should be much t...

No worries, thanks again. I've put your code and an explanation in the SkyRoads compression article on the ModdingWiki. I've also found that the image files use the same compression algorithm, so I've been able to start reverse engineering some other files too.

Fantastic, many thanks! I had to adjust the code a little - where you have "count = 1 + getbits..." I had to change it to "2 +" and then it worked perfectly.

Thanks to this, hopefully it won't be too long now before SkyRoads levels can be edited in Camoto!

Hi all, I'm trying to reverse engineer the compression algorithm used by the DOS game SkyRoads to compress its levels. I've attached four example files, both compressed and decompressed. The decompressed versions were obtained from a DOSBox memory dump, so there are extra trailing 0x00 bytes. The fi...

I've just posted a version of Camoto (version 20131117) that can kind of edit Zone 66 levels. You can open the level, change it, and save it, but for some reason the game locks up when it tries to load the modified level. I don't know why it does this, but there must be a problem with the compressio...

Last post - I've successfully reverse engineered this file format. I am in the process of writing up an explanation for the full encryption algorithm and the file structures, which will appear shortly on the ModdingWiki page for the GLB format.

Just to save anyone the time on this, I have reverse engineered the algorithm used by the game and so this problem is now solved. As it turns out the game does not quite use XOR, which is why the values were appearing strangely. I am in the process of writing up an explanation for the full encryptio...

Hi all, I am struggling to decrypt the filenames in the Raptor GLB format. I have obtained the decrypted filenames from a memory dump, but I am stuck trying to figure out the decryption algorithm. Here is the mapping between the encrypted bytes and the decrypted data. Each character position has a s...

I have a C++ utility header that can also do this.

I've just had a closer look at this format, and this is what I have discovered so far: Only the FAT (the list of filenames and offsets) is encrypted. This is the first 43008 bytes of the file, which is 768 file entries of 56 bytes each. I have only managed to partially decrypt so far. By taking each...

Sorry about digging up such an old topic, but I was just going to post the same question anyway.

Does anyone know if any progress has been made in the last five years with this file format?

Thanks for investigating.

I've had an e-mail from someone who disassembled the algorithm and coverted it to C. If anyone is interested, I will be documenting it over the coming weeks on the Game Modding Wiki and of course implementing it in Camoto/libgamearchive.

Looking at this further, it seems there are actually two variants to the compression, but they all seem to be based around byte pair encoding . Focusing on one for the moment (the one in the files I posted above), it seems to be roughly in this structure (using data from title.mod as an example) 50 ...

Hi all, Following on from this post back in 2006 I had another look at the Stargunner compression format. It looks tantalisingly simple, but alas I'm struggling somewhat. I've uploaded a couple of files (compressed and decompressed versions) so if anyone is willing to take a quick look that would be...

Yeah everything's almost back to normal now, just a lot of cleanup going on. My local supermarket is still closed while they clean out the mud, but at least I didn't have to rip out and replace everything in my home (including the walls) like those people whose places went under... And yes, this is ...