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ChaosKnight · Joined: 14 Apr 2005 Posts: 142 Location: Florida, USA

The PBP is an uncompressed archive file, the contents are thusly:

PARAM.SFO - You can change what's in here to modify text and region codes etc...

ICON0.PNG - A PNG that's displayed as the game / game save icon. (144x80 px)

ICON1.PMF - A video icon file. It's encoded with AVS.

UNKNOWN.PNG - A larger icon sits in the lower right corner of the screen. (Don't know pixel dimensions but it's considerably bigger than ICON0.PNG)

PIC1.PNG - Background image (480x272px)

SND0.AT3 - An ATRAC3 encoded wav file. Plays while you have the icon selected.

UNKNOWN.PSP - The PSP Executable? (Encrypted/Compressed)?

UNKNOWN.PSPAR - An archive containing a filesystem? (Encrypted/Compressed)?

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So far there are several programs for editing these files. They are all mentioned on these forums, look around and see what suits you best. PDC made a very nice looking one, and mine has a PARAM.SFO editor and PNG preview, I know there is at least one more but I haven't used it personally.

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This list may be inaccurate / incomplete, feel free to post updates/fixes.

Thanks.
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MelGibson · Joined: 10 Apr 2005 Posts: 58

This doesn't concern the PBP file format directly, but the link to the recent firmware EBOOT.PBP contains the MD5 checksum of the file...

http://dj01.psp.update.playstation.org/update/jp/2005_0324_e32eb27980ba8b291eb803e3397e4b24/EBOOT.PBP

e32eb27980ba8b291eb803e3397e4b24 being the MD5 checksum of EBOOT.PBP

th3count · Joined: 14 Apr 2005 Posts: 7

what would putting this firmware on a US PSP do? change everything to japanese language?

jyopp · Joined: 14 Apr 2005 Posts: 2 Location: Central Florida, USA

Okay, I spent a few minutes playing with UNKNOWN.PNG to find its size, and found out two (hopefully) useful things. I created a file with a 1-pixel checkerboard pattern (the old-school "50% Grey"), inserted it into an EBOOT.PBP file, and sized it to the display area by counting up visible artifacts.

1. The size of the image appears to be (310x180px).
2. The internal representation of this image is probably done by loading it as a (compressed) texture into the graphics accelerator -- even with no stretch artifacts (which appear as gradiated bars / diamonds), there is still some distortion, seen as overlapping dark/light regions on the image...

(The effect you see on the grey panel is in the PSP, not the camera.)

ChaosKnight · Joined: 14 Apr 2005 Posts: 142 Location: Florida, USA

Awesome work figuring out that resolution. I like the 1 up mushroom too.
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jyopp · Joined: 14 Apr 2005 Posts: 2 Location: Central Florida, USA

I don't remember what thread the comment was in, but ChaosKnight said something about the PSAR file looking zlib-compressed...

I'm working on a simple program to probe the files for obvious compression methods. So far, we can rule out simple zlib compression. I scratched the original program together in Delphi, so it's very slow. I'm going to rewrite it in gcc as a command-line tool, and start changing out the compression/decompression libraries for other possiblities (like gzip or bz2) as time permits, to see if we can get some worthwhile data out of them.

Is there a text string I can search for in the PSAR file?

MelGibson · Joined: 10 Apr 2005 Posts: 58

I think besides PSAR in the header there is no other textstring inside the archive

505341520200000020DE9A0001000000 PSAR.... .......

ChaosKnight · Joined: 14 Apr 2005 Posts: 142 Location: Florida, USA

Mel Gibson is right. Also, I'm pretty confident that although the file may or may not be compressed, it is most definately encrypted. So sorry jyopp, you program will likely not work with any decompression algorithm.

It would be pretty careless of Sony to not encrypt the firmware.
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