LZ4 MOD for *certain* game's data archives | repacks

[panker1992]

Last time i checked demon souls isnt out for pc yet !!!

are you telling me you have a secre that it may come out ?

[L33THAK0R]

Originally Posted by panker1992

Last time i checked demon souls isnt out for pc yet !!!

are you telling me you have a secre that it may come out ?

@panker1992, sorry I should have clarified. I'm currently repacking console exclusives, as I've figured out how to pack some trickier microsoft/sony container-types, and have been getting good ratios. Although Xenia (Xbox 360 emulator) progress is slow, RPCS3 (PS3 emulator) development has had a decent uptick in progress. "Demon's Souls" for the PS3 (not PS5) contains LZ4 streams, however this is based entirely off of investigating the methods used in 2 repacks of the title (A Darack team-member, & Gnarly), the former of which is currently offline due to personal issues, and the latter being unable to recall their methodology. I currently can't say which files (of which there are ~6000) contain the LZ4 streams, as the GFS tool is unable to detect any.

I'm also not sure how to identify if LZ4 compression was used, like how the Authors other project ZSTD can be, by examining the first 4 bytes in a hex editor.

[Masquerade]

LZ4 can be used without header info. This also confused me at first. I'm out of country currently, but I definitely intend to do some more research when I get back.

Btw you could encounter problems analysing the data since desktop PCs are little endian whereas the PS3 had a CPU made by PowerPC which is big endian iirc.

[L33THAK0R]

Originally Posted by Masquerade

LZ4 can be used without header info.

This is both fascinating and slightly depressing, just when I think I'm starting to understand the basics of these algorithms, I realise I'm yet to even scratch the surface.

Originally Posted by Masquerade

Btw you could encounter problems analysing the data since desktop PCs are little endian whereas the PS3 had a CPU made by PowerPC which is big endian iirc.

Damn I hadn't considered the architecture differences. I suppose though it shouldn't be too hard to determine if a mainstream compression algorithim is being used, through trial and error, should a universal methodology for LZ4 pre-compression be developed (which from the sounds of things would be no easy feat).

[Masquerade]

Originally Posted by L33THAK0R

I realise I'm yet to even scratch the surface.

Welcome to the party.