Unpack, pack, list, test and mount Unreal Engine 4 .pak archives.
u4pak.py list <archive> - list contens of .pak archive u4pak.py test <archive> - test archive integrity u4pak.py unpack <archive> - extract .pak archive u4pak.py pack <archive> <files> - create .pak archive u4pak.py mount <archive> <mount-point> - mount archive as read-only file system
Only unencryped and uncompressed archives of version 1, 2, and 3 are supported. Note that only version 2 and 3 are tested.
mount command depends on the llfuse
Python package. If it's not available the rest is still working.
This script is compatible with Python 2.7 and 3 (tested with 2.7.5 and 3.3.2).
Only what is absolutely necesarry to read archives is reverse engineered.
Byte order is little endian and the character encoding of file names seems to be ASCII (or ISO-8859-1/UTF-8 that coincidentally only uses ASCII compatiple characters).
Offsets and sizes seem to be 64bit or at least unsigned 32bit integers. If interpreted as 32bit integers all sizes (except the size of file names) and offsets are followed by another 32bit integer of the value 0, which makes me guess these are 64bit values. Also some values exceed the range of signed 32bit integers, so they have to be at least unsigned 32bit integers. This information was reverse engineered from the Elemental Demo for Linux (which contains a 2.5 GB .pak file).
- Data Records
- Index Header
- Index Records
In order to parse a file you need to read the footer first. The footer contains an offset pointer to the start of the index records. The index records then contain offset pointers to the data records.
Offset Size Type Description 0 8 uint64_t offset 8 8 uint64_t size (N) 16 8 uint64_t uncompressed size 24 4 uint32_t compression method: 0x00 ... none 0x01 ... zlib 0x10 ... bias memory 0x20 ... bias speed if version <= 1 28 8 uint64_t timestamp end ? 20 uint8_t data sha1 hash if version >= 3 if compression method != 0x00 ?+20 4 uint32_t block count (M) ?+24 M*16 CB[M] compression blocks end ? 1 uint8_t is encrypted ?+1 4 uint32_t compression block size end if version >= 4 ? 1 uint32_t unknown end
Compression Block (CB)
Size: 16 bytes
Offset Size Type Description 0 8 uint64_t start offset: Absolute offset of the start of the compression block. 8 8 uint64_t end offset: Absolute offset of the end of the compression block. This may not align completely with the start of the next block.
Offset Size Type Description 0 ? Record file metadata (offset field is 0, N = compressed_size) ? N uint8_t[N] file data
Offset Size Type Description 0 4 uint32_t file name size (S) 4 S char[S] file name 4+S ? Record file metadata
Offset Size Type Description 0 4 uint32_t mount point size (S) 4 S char[S] mount point S+4 4 uint32_t record count (N) S+8 ? IndexRecord[N] records
Size: 44 bytes
Offset Size Type Description 0 4 uint32_t magic: 0x5A6F12E1 4 4 uint32_t version: 1, 2, or 3 8 8 uint64_t index offset 16 8 uint64_t index size 24 20 uint8_t index sha1 hash
- fezpak: pack, unpack, list and mount FEZ .pak archives
- psypkg: pack, unpack, list and mount Psychonauts .pkg archives
- bgebf: unpack, list and mount Beyond Good and Evil .bf archives
- unvpk: extract, list, check and mount Valve .vpk archives
- t2fbq: unpack, list and mount Trine 2 .fbq archives
Copyright (c) 2014 Mathias Panzenböck
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