Would appreciate some advice regarding this .arc container [Pitfall: The Lost Expedition]

Extraction and unpacking of game archives and compression, encryption, obfuscation, decoding of unknown files
panconver
Posts: 6
Joined: Wed Jan 03, 2018 10:57 pm

Would appreciate some advice regarding this .arc container [Pitfall: The Lost Expedition]

Post by panconver »

To give some context:
I recently picked up the old platformer "Pitfall: The Lost Expedition" again. Got it around launch (2004), but haven't had the chance (or bothered) to poke around with the game files until recently, with my discovery of the Dolphin GameCube emulator, and a successfull softmod of my XBOX.
So, the game got my attention again, but this time from a different perspective than back at launch.

With some newfound curiosity regarding the inner workings of the game, I decided to try my way to open up the core visual components: sounds, textures, level maps and models.

To narrow my search down, I decided to focus on the XBOX files, as I'd rather avoid big endian data formats.
I managed to unpack the files from both the XBOX and GC disk image. It appears as if the assets are packaged up in a container format, identified by the '.arc' file extension. So I've spent some time trying to make sense of the data within.

The game engine is developed in house, by the studio 'Edge of Reality' (in other words: proprietary). Looking into their portfolio, most notably the sims content (as it has a somewhat bigger fan-base), I found quickBMS and aluigi's arc bms script. Using that, I managed to extract a list of the files within the arc containers. Trying out a few similar scripts, 360 Hulk and 'Over the Hedge', and a couple of tweaked sims arc bms scripts, I managed to get some data out of it as well.

This is where my momentum ended. Raw binary pattern analyzation and file format knowledge is something I don't have experience of yet, and given that I only got binary data out of the game disk, I'm pretty much stuck. I have tried a couple of the game rippers recommended here, but neither have been able to identify any textures, or sounds for that matter. Scalpel and Foremost only gave false positives throughout the whole disk image, leading me to assume some form of non-standard compression, or maybe even encryption?

My next plan was to step through the game's launch sequence with Dolphin's built-in debugger/disassembler, to see how it handles the files, but I'm concerned that it is going to take a lot of time to do so, as it probably has to load and execute routines of the game engine to establish the framework in which the game itself runs, and I've yet to see a "light" game engine.
Plus my poor knowledge of assembly.

Maybe someone can shed some light on my niche hobby?
If I find something, I'll update this post.

I'll attach some light files below, if anyone wants to have a look.

EDIT: No luck regarding the file formats, but all console versions of the game can be extracted with the 'maxis_ind.bms' script AnonBaiter linked below. Cheers.
Last edited by panconver on Mon Feb 05, 2018 11:21 am, edited 2 times in total.
aluigi
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Re: Would appreciate some advice regarding this .arc container [Pitfall: The Lost Expedition]

Post by aluigi »

What was the exact script you used to extract the files?
The format is simple but it lacks a magic (an identifier string) so it's difficult to find it in my collection.

Regarding the extracted files, custom formats are ever painful but I remember that there were some topics and discussions about Over the Edge, not sure if the format of the files is the same (for sure not that of the arc archives).
panconver
Posts: 6
Joined: Wed Jan 03, 2018 10:57 pm

Re: Would appreciate some advice regarding this .arc container [Pitfall: The Lost Expedition]

Post by panconver »

It was 'sims2_arc.bms', which I found referenced in this thread: viewtopic.php?f=9&t=4855

I did try the 'sims2_gc.bms' version on one of the gamecube files, with the following result:

Code: Select all

$ quickbms bms/sims2_gc.bms disks/gc_game/files/sounds.arc 

QuickBMS generic files extractor and reimporter 0.8.1
by Luigi Auriemma
e-mail: me@aluigi.org
web:    aluigi.org
        (Sep  9 2017 - 09:58:41)

                   quickbms.aluigi.org  Homepage
                            zenhax.com  ZenHAX Forum
                               @zenhax  Twitter & Scripts

- open input file /home/<username>/Desktop/pitfall-tle/disks/gc_game/files/sounds.arc
- open script bms/sims2_gc.bms
- set output folder .

  offset   filesize   filename
--------------------------------------
  000073a3 1701733681 Scene10LeechLine2/

Error: incomplete input file 0: /home/<username>/Desktop/pitfall-tle/disks/gc_game/files/sounds.arc
       Can't read 676078 bytes from offset 000622b5.
       Anyway don't worry, it's possible that the BMS script has been written
       to exit in this way if it's reached the end of the archive so check it
       or contact its author or verify that all the files have been extracted.
       Please check the following coverage information to know if it's ok.

  coverage file 0    92%   372636     402101     . offset 000622b5

Last script line before the error or that produced the error:
  32  log NAME OFFSET1 SIZE1


Ok, I'll have a look regarding the hedge discussions :)
AnonBaiter
Posts: 1125
Joined: Tue Feb 02, 2016 2:35 am

Re: Would appreciate some advice regarding this .arc container [Pitfall: The Lost Expedition]

Post by AnonBaiter »

I worked with this kind of format a few months ago. My focus regarding this format was The Sims series of games, as released on consoles.

Eventually, I decided to write a script for this a while back. I had to do a lot of testing with this script, so this might work with your case too.
panconver
Posts: 6
Joined: Wed Jan 03, 2018 10:57 pm

Re: Would appreciate some advice regarding this .arc container [Pitfall: The Lost Expedition]

Post by panconver »

Thanks AnonBaiter. Your version did manage to extract both the XBOX and GameCube files :D
It turns out the original sims2_arc.bms was giving the same results when used on the xbox files. Did a directory diff to confirm.
Which leads me to conclude that the data is in some customized format.

Now I have two platforms to look for though, which at least gives me options and a broader search area.
Will have to learn about all the different file formats there are. Thanks for helping me get past this hurdle :)
AnonBaiter
Posts: 1125
Joined: Tue Feb 02, 2016 2:35 am

Re: Would appreciate some advice regarding this .arc container [Pitfall: The Lost Expedition]

Post by AnonBaiter »

You're welcome I guess.
Mrfranci3000
Posts: 1
Joined: Sat Jan 25, 2020 9:59 am

Re: Would appreciate some advice regarding this .arc container [Pitfall: The Lost Expedition]

Post by Mrfranci3000 »

You can play (and convert) the extracted audio files from "audiostr" and "samples" folders using vgmstream.