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puggsoy, posted Fri Aug 28, 2015 2:04 pm (6952)

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Can someone identify the type of compression used on these .pkg files?

Ekey, posted Fri Aug 28, 2015 3:59 pm (6954)

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https://bitbucket.org/alisci01/xnbdecompressor/src

puggsoy, posted Sat Aug 29, 2015 3:34 am (6956)

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Ah, this is the compression for XNB files. What I was referring to was the compression of the .pkg files themselves, which contain the XNBs. I can tell they're compressed because the filenames near the start are broken in seemingly random places (e.g. "bin\Win\Atlases\Tracker_T.extures00" in Tracker.pkg), and also because the metadata in the XNB files says the file is much larger than it actually is.
Each file starts with these bytes:

Code:

40 00 00 05 01 00

Which seems to suggest some sort of identifiable algorithm; I just can't find what it is.

That said, I do appreciate the link. I was looking for a publicly available implementation of XNB decompression

Ekey, posted Sat Aug 29, 2015 6:04 pm (7001)

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It's normal XNB file with custom header > cut him > example:

puggsoy, posted Sun Aug 30, 2015 3:36 am (7012)

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I compiled the decompressor, that doesn't work. Here, you can try it yourself. I'm pretty sure the .pkg is compressed.

XNBDecompressor.zip

puggsoy, posted Sun Sep 06, 2015 7:13 am (7234)

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Bumping just in case someone can still figure this out?

puggsoy, posted Wed Dec 02, 2015 9:24 pm (10262)

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Bump, maybe it's possible now? Really want to extract these files.

aluigi, posted Sun Dec 06, 2015 6:59 pm (10348)

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Just a quick test I did to not leave the thread unanswered.
I have launched the comtype_scan2 scanner against Uppercut.pkg from offsets 0, 4 and 7, then I did a "grep" to search the keyword "Microsoft" and found results in the test 26 and 371.
26 is a false positive but 371 seems correct, it's the UNKNOWN6 algorithm.
Can you check it?

Code:

comtype unknown6
math OFFSET = 4
get ZSIZE asize
math ZSIZE - OFFSET
xmath SIZE "ZSIZE * 20"
get NAME basename
clog NAME OFFSET ZSIZE SIZE

Savage, posted Mon Jun 13, 2016 10:13 am (14357)

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puggsoy wrote:

Bump, maybe it's possible now? Really want to extract these files.

Try this,

http://pastebin.com/TkZZKqUW

Original source:
https://www.reddit.com/r/transistor/com ... re_ripper/

The bms only works with a few files

Ekey, cutting the headers is not working with this files

aluigi, posted Mon Jun 13, 2016 10:43 am (14359)

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So, basically, it's an xmemdecompress used on chunks of the file, right?

puggsoy, posted Wed Jan 18, 2017 11:13 pm (20294)

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Oh wow thanks a lot Savage, I'd kind of given up on this and forgotten about it.

The guy you linked to has some updated code here, which seems to go into a bit more detail on how to decompress the files (I think without needing .dlls from Transistor itself, and/or as many built-in XNA/MonoGame stuff). It seems to have a release, I'll try that out later today, otherwise I can maybe port what he has over to a language I can work in.

Aluigi, it appears to be something called "LZF" compression on chunks, if you go to around line 380 of this file.

aluigi, posted Thu Jan 19, 2017 6:47 pm (20303)

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Ah like this:

Code:

comtype lzf
math CHUNK_SIZE = 0x800000
math COMPRESSION_FLAG = 0x40000000
math PACKAGE_VERSION_CODE = 5
endian big
get packageHeader long
get NAME basename
log NAME 0 0
append
get PKG_SIZE asize
for OFFSET = 4 != PKG_SIZE
    get ZIP byte
    if ZIP != 0
        get CHUNK_ZSIZE long
        savepos OFFSET
        clog NAME OFFSET CHUNK_ZSIZE CHUNK_SIZE
        math OFFSET   CHUNK_ZSIZE
    else
        savepos OFFSET
        log NAME OFFSET CHUNK_SIZE
        math OFFSET   CHUNK_SIZE
    endif
    goto OFFSET
next
append

Savage, posted Mon Mar 27, 2017 7:19 pm (21796)

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Aluigi, the script works like a charm, but the game doesn't work with the files unpacked, i already packed the files using this script, but the game crashes too

Code:

comtype lzf_compress
get SIZE asize
get NAME basename
get EXT extension
string NAME   ".pkg"
string NAME   EXT
clog NAME 0 SIZE SIZE

aluigi, posted Wed Mar 29, 2017 3:10 pm (21835)

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As far as I can see from my script it requires for sure more than that lzf_compress clog to work
There is clearly an header and chunks