Weird DTA compressed file in Mafia

[teusma]

In Mafia there is a file called "A0.dta" with 9,439 files - all of them in wav (PCM) format, this file is compressed and encrypted... but what's interesting about that? I'll explain as best I can, I hope what I discover is clear... There is a tool that supports the extraction of these files (wav pcm) that is compatible with msc_tak and when compressing these wav files, it is 989 MB (after already extracted from the A0.dta file) and becomes 576 MB. If I run 7z lzma 2 over it and try to compress it even more, I can save only about 700 kb. If I compress the folder with these wav files without running msc_tak first, it becomes 654 MB, but where am I going with this? - That's where the trick comes in, the A0.dta file when still intact encrypted/compressed (a proprietary compression that I have no idea what it is... maybe a lz77 variant from what I've read) it consumes 495 MB of disk space and if you compress it even more with 7z lzma2 it goes down to 343 MB. Now explain to me how the hell does this happen??? recap:
the size of the intact file is: 495mb

when extracted (undoes the proprietary compression) it goes to 989MB

when I compress these extracted files (wav) with msc_tak it drops to 576MB and even if I compress it even more with lzma2 it only loses ~700kb

if I just compress these extracted files (wav), with 7z lzma2 it goes to 654mb

and if I simply compress the A0.dta file as it is (without decrypting and uncompressing the proprietary compression) it ends up with 343MB - much smaller!!!:...

now? I wonder if there is a way to "usurp" this proprietary compression to create a wav pre-processor and use it in other wav files from any other game...

And I'm still going to test if the other files also behave this way to see if it's only with A0.dta or if it also happens with A1.dta, A2.dta, A3.dta... if this happens.

What do you think of all this? Am I making a mistake in some way???

I'll leave the files for download so you can see for yourself:

https://www.mediafire.com/file/zev2u...ractor.7z/file