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Kono, posted Sun Nov 28, 2021 12:02 pm (67733)

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I was just looking through some switch game, and I found a Renpy game. There is some graphic file in it, some seem to be compressed.

I can read the header, but I can't determine the compression algorithm. It's build as

Code:

0x00 -> 0x04 = Unknown number, maybe magic number
0x04 -> 0x08 = Supposedly bit per color
0x08 -> 0x0C = height (1080p)
0x0C -> 0x0F = width (1920p)

After that there is a stream which seem to be compressed. I can't figure what is the compression algorithm as there is no magic number. I uploaded few sample images.



Thank you for your time !

Allen, posted Sun Nov 28, 2021 1:49 pm (67739)

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They are double-layer LZ4 compression.

Code:

# Renpy Switch Game
# script for quickbms
# by Allen

comtype lz4
get magic long
get bpp long
get width long
get height long
get SIZE long
get ZSIZE long
get name basename

string name   ".dcmp"
savepos OFFSET
log MEMORY_FILE 0 0
clog MEMORY_FILE OFFSET ZSIZE SIZE
get SIZE long MEMORY_FILE
get ZSIZE long MEMORY_FILE
savepos OFFSET MEMORY_FILE
clog name OFFSET ZSIZE SIZE MEMORY_FILE

Kono, posted Tue Nov 30, 2021 2:03 pm (67769)

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Indeed, it works ! Thank you