I got some game compression data which I couldn't find any clue. All compressed file signature start with: [SK_ASC] and unknown compression method.
I got some information from RAM/Executive file but still didn't work. I think the compression is the lossless format (But it's not a LZO nor ZLIB). Can anyone help me figure out the compression, and how to decompress?
- All of example file above can be found here: http://goo.gl/JJQfl4
=== 10.25.14 ADDED ===
The list below compression method that I tested, but doesn't match:
- HUFF blocksize 4 & 8 byte
=== 10.26.14 ADDED ===
Today I analysis something via memory dump.
First of all, compressed
EMnMenu.cmp file could be loaded when I enter the main menu by guessing it's file name. and there are very similar files which is unused. (
So I try to check memory dump by replacing file each other. and I got
dump_kioskmenu.ram. By comparing three different ram dump data,
I found out only specific offset data is changed.
By using this method, I finally got a decompression data dumped via offset: 0x80CA6980. Decompressed data is well known texture which was first 4 byte signature start with 0x00 0x20 0xAF 0x30. (check texture format here: http://goo.gl/UqLz3m)
I try to find compression algorithm by compressing the decompression data and compare with original data. but non of algorithm that I test above doesn't match.
Anyway, I uploaded several decompressed data via ram dump and compressed data so you can check here: goo.gl/JJQfl4
- CMP is a compressed data which always start with SK_ASC.
- BIN is a same as CMP.
- DCMP is a instant copy from memory file, which was extracted from offset 0x80CA6980.
- DMP is a data value correction by subtracted 0x80CA6980 because there so many memory scrapping dummy (so this is the cleaned decompressed data if I guess right)
ADDED Didn't work with regular deflate/zlib all compress level.
== 11.09.14 ==
I posted several forum to help, but no clue for weeks :(
== 11.15.14 ==
Other forum user said to me there are Gamecube DOL (executive file) plugin for IDA. So I use them and now I've found decompression main/algorithm subroutine. Would anyone help me find out describe how it works?
(I'm not well in dis-assembly, So I'm learning now)
Power PC based Dis-Assembly skill Required