Unreal Engine 4 replays

[TSG]

Hi! I was told zenhax was the place I should come to for this. I have a .replay file used by the Unreal Engine. I would like to be able to decompress these files and recompress them. I have found they are compressed with Oodle LZB16 at a Very Fast compression level. I DO NOT own the Oodle SDK. Would it be possible to decompress with just this information? I cannot provide a sample at the current time of posting, but I will be able to if someone asks.

[aluigi]

I know that format and, yes, it uses oodle.
The initial part consists in decompressing the main chunks and it's simple, but parsing the data of the chunks is complex.

[TSG]

Alright, well. I don't know where to go about this, so here's a sample. I had to rename the extension to .bin, but the original extension is .replay

[aluigi]

I can give you an example but that's the max I can do (the format changes often and so on):
offset 0x000107b2 DecompressedSize = 0x0001a5b9
offset 0x000107b6 CompressedSize = 0x00008241
compressed data starts at offset 0x107ba

Code: Select all

comtype oodle
goto 0x000107b2
get DecompressedSize long
get CompressedSize long
savepos OFFSET
clog "dump.dat" OFFSET CompressedSize DecompressedSize

Remember that it's only an example of one compressed chunk.

*edit* fixed

[TSG]

Hi! I had a look at the output this script gave, and strings and whatnot appear to still be compressed

[aluigi]

Oh sorry, my fault.
Script is now fixed