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TripleL, posted Fri Jan 06, 2017 6:13 am (19975)

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Hello, I've been trying to open the sprite files for the Danganronpa v3 demo. I've tried a lot of methods to open these files but no dice. Hopefully one of you can figure this out.

Attachments didn't work so here's the mega download of all the files i'm trying to get open https://mega.nz/#!6xtmgBzQ!RNfIUlC94bQs ... KdaxqRtCp8

chrrox, posted Sat Jan 07, 2017 1:54 am (19990)

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I bet its the same compression as one piece burning blood.

TripleL, posted Sat Jan 07, 2017 6:33 am (19991)

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chrrox wrote:

I bet its the same compression as one piece burning blood.

I think those are .scz

chrrox, posted Sat Jan 07, 2017 11:51 am (19996)

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That is just a container name.
The compression looks the same.
Also same developers.
http://store.steampowered.com/search/?d ... ., Ltd.

TripleL, posted Sat Jan 07, 2017 11:29 pm (20008)

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chrrox wrote:

That is just a container name.
The compression looks the same.
Also same developers.
http://store.steampowered.com/search/?d ... ., Ltd.

How would i go about extracting it? I apoligize, I'm new to compression reverse engineering.

chrrox, posted Sun Jan 08, 2017 2:07 am (20009)

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you could reverse engineer the decompression function from one piece burning blood on pc.
One piece burning blood is an unkown compression currently used by that company in many of thier games.

DrDaxxy, posted Sun Jan 08, 2017 8:57 am (20014)

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(In case this wasn't obvious by now, this thread is in the wrong forum, SPC is an archive format, not graphics)

I don't think DRV3 .SPC files use the same compression algorithm as OPBB .SCZ. I attempted to get the OPBB executable to decompress a file from an .SPC by replacing the first chunk in an .SCZ in the game's memory before decompression (adjusting the sizes in said .SCZ's TOC entry accordingly) and only got garbage back.

I've attached another sample compressing a file of a more or less well-known format (CRIWARE ACB).

The entry of the first (and only) file in that archive starts at 0x50.
0x50-0x51 (here: 02 00) identify the compression algorithm. Some .SPC's I've looked at contain uncompressed files, for which that number is 01 00
0x52-0x53 (here: 04 00) is of currently unknown purpose. I've also seen it be 01 00 and (IIRC) 08 00 in other files. For the uncompressed file I've looked at this is also 04 00.
0x54-0x57 and 0x58-0x5B are the compressed and uncompressed file size, respectively.
0x5C-0x5F are the file name length, though the actual file name field is padded to 16 bytes.
After that, a bunch of null bytes, then the file name field, so the compressed data goes from 0x70 to (in this case) 0x57636.

Other recent Spike Chunsoft games use either no compression (inside the CPKs) or what looks like OPBB's compression. I've run this through the comtype scanner and nothing worked. So at this point I believe this is a new, original compression algorithm.

Analysing those without access to (de)compression code - there's currently no way to decrypt PS Vita game executables requiring firmware 3.61 or higher - is out of my league, but if anyone wants a challenge, we'd appreciate the help

chrrox, posted Sun Jan 08, 2017 12:28 pm (20015)

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Both compression's look like a type of lz compression.
There is no way to know they are the exact same until we get
the executable as you said.
Both contain complete or near complete strings in the compression.
they could change one thing in the compression and it would throw it off.
What is wierd is there is no way of extracting the vita code and someone
is posting decompressed images.
So there are only a few options.
1.They have access to some original files somehow.
2.They found the decompression code in another game and used it with this game.
3.They have a lot of time on their hands and manually reversed the compression because they know what the original data should look like.