Author Topic: .J2B file format  (Read 21632 times)

Tsorovan

  • Posts: 1247
Re:.J2B file format
« Reply #25 on: 8 Oct '03 - 18:22 »
Could be worth trying getting in touch with Carlo Vogelsang who nowadays works for Creative.

Haze

  • Guest
Re:.J2B file format
« Reply #26 on: 8 Oct '03 - 20:14 »
Chalk it up to Alexander Brandon not having the exact files that were included in the game. Perhaps he only had older versions of the songs, or made changes to them before giving them to Lori Central. (Or perhaps LC did more than tag all of the files with an advertisement... I doubt it.)

The first scenario being indeed the case. ;) Lori Central (which I co-administrate) really did ONLY include the extra tags, which was basically a requirement set by Alex himself IIRC.

It would indeed be a wise idea to try and get in contact with Carlo Vogelsang. From a recent interview one can determine that he at least remembers the Galaxy Music System. :)
http://developer.creative.com/articles/article.asp?cat=1&sbcat=31&top=38&aid=95

Haze

  • Guest
Re:.J2B file format
« Reply #27 on: 10 Oct '03 - 13:20 »
FYI contact has been established and our plea for help has been forwarded to the "proper authorities". ;)

Haze

  • Guest
Re: .J2B file format
« Reply #28 on: 14 Sep '05 - 23:42 »
Wow, an old topic brought back from the dead. And I still haven't registered? ;D Oh well. Just wanted to point out that if interest was still afloat for the J2B-format someone has cracked the decompression and put up some sourcecode over at http://www.jazz2online.com/J2Ov2/articles/view.php?articleID=288.
Sure, a plugin would work as well but unfortunately I'm no (Win32) coder.  :'(

kode54

  • Posts: 100
Re: .J2B file format
« Reply #29 on: 15 Sep '05 - 03:13 »
I already knew as much about the compression, but I never bothered to deconstruct the format within. That page says it's Epic's pattern format, but Epic never used it in any other games. I'm thinking it's more like the Galaxy (Sound/Music/?) System's internal format. The only tool which identified it as a supported format was the short lived MOD2J2B tool, which listed AM amongst the supported extensions. The tool also credited a programmer from digitaldreams.nl, the now defunt domain of Galaxy and related products.

One "fun" way you can have at it is double reverse engineering! First you can deconstruct Galaxy's internal structure layout by how MOD2J2B assembles various formats in memory. Second, you see where it pulls data from when constructing the new RIFF AM file prior to compressing it. I never felt like doing this, especially after I discovered original IT format versions of the soundtrack at loricentral.com... Which is also dead at this time.

A bit of an assist to save some time documenting internals to find that info, any willing hacker may try filling various fields in supported source formats with various incrementing (and legal for the particular field) values, then see where it plonks them. The only problem is if it supports a greater precision for any of the header values and scales them. There's always the possibility of writing a tool to modify the header of an existing file in exactly one field at a time, then seeing where the output changes for each field.

Orders list and patterns should be significantly more easy, since you only have to discover what it translates each effect to, and possibly scales their parameters to depending on the source. There's also possible header flags that depend on which source format you translated from, to enable quirks specific to MOD and derivatives, S3M, or XM.