ERF

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ERF editor

ERF ("Encapsulated Resource File") files are container files for game resources.

Contents

List of common ERF Files

ERF Files for Dragon Age Game Resources are stored in the (Dragon Age Install Dir)\packages\core\ Folder and Subdirectories. ERF's for Addons or Mods are usually in their respective Addon or Mod Folder.

Common ERF's of certain interests are,

Extracting Resources

The Toolset is capable of extracting ERF Files Contents.

If you are modding Resources, the first step would be extracting Resources. You may start of by extracting all Resources of certain interest to you, or just a single File. To Maintain a simple and clean resource place, it is best to use a similar Folder Names to extract in.

One may create a Folder on the HD named for example "gameresources". Then added with subfolders that suit the Purpose, for example "Materials" in which one extracts only Materials. Preferably the Folderscheme is similar to that of the ERF's, to make browsing simple and easy to remember.

Packing Resources

The builder to player process packages up resources into ERF files for you, storing the generated ERFs inside DAZIPs.

Additionally, you can edit any ERF by opening it directly in the Toolset, and add or remove files by drag& dropping them into the Toolset with the ERF open manually. In cases the above process fails or whenever.

Overriding Resources

ERF's are named by their general purpose. But not all material files need to necessarily be put into Materials.ERF as an example. Patches do add every Patched Resource into one single ERF for example. The Original Game Resource ERF Files however are best left alone, as it has a high risk of breaking the game.

Files do not need to be present in ERF Files at all. When Overriding Gameresources as when modding, this is a pretty easy method. Overriding Files are of equal name to their original Gameresource counterpart, and are to be placed into packages\core\override\. The Game will then choose this File over the original.

File Format

Version 2.0

All values are little-endian.

Header

Name Type / Size Info
magic utf16[8] "ERF V2.0", a total of 16 bytes.
fileCount uint32 Number of files encapsulated in this ERF.
year uint32 Year since 1900.
day uint32 Day since January 1st.
unknown uint32 Always 0xFFFFFFFF?

Table of Contents

Name Type / Size Info
toc entry[fileCount]

Entry

Name Type / Size Info
name utf16[32]
offset uint32 Offset to entry file data, from start of ERF file.
size uint32 Length of file data.

Version 2.2

This version introduces support for encrypted and compressed file data.

All values are little-endian.

Header

Name Type / Size Info
magic utf16[8] "ERF V2.2", a total of 16 bytes.
fileCount uint32 Number of files encapsulated in this ERF.
year uint32 Year since 1900.
day uint32 Day since January 1st.
unknown uint32 Always 0xFFFFFFFF?
flags uint32 Bit flags

Flags:

  • 0x00000001 (bit 0) : Unknown
  • 0x000000F0 (bits 4 - 7) : Encryption scheme
  • 0xE0000000 (bits 29 - 31) : Compression scheme

Encryption scheme: (flags >> 4) & 0xF

  • 0 : None
  • 1 : XOR
  • 2 : Blowfish
  • 3 : Blowfish (Dragon Age 2 only)
  • Any other value is invalid.

Compression scheme: (flags >> 29) & 0x7

  • 0 : None
  • 1 : Bioware Zlib (Dragon Age 2 only)
  • 2 : Unknown (Dragon Age 2 only)
  • 3 : Unknown (Dragon Age 2 only)
  • 7 : Headerless Zlib (Dragon Age 2 only)
  • Any other value is invalid.
moduleId uint32 This id is used to look up the password for the ERF when encryption is present, for example, DLC.
passwordDigest byte[16] MD5 sum of password (as a string).

Table of Contents

Name Type / Size Info
toc entry[fileCount]

Entry

Name Type / Size Info
name utf16[32]
offset uint32 Offset to entry file data, from start of ERF file.
packedSize uint32 Packed length of file data.
unpackedSize uint32 Unpacked length of file data.

Version 3.0

Found in Dragon Age 2.

This version introduces hashed file names (and extensions) for faster file lookup.

All values are little-endian.

Header

Name Type / Size Info
magic utf16[8] "ERF V3.0", a total of 16 bytes.
stringTableSize uint32 Size of the file name string table.
fileCount uint32 Number of files encapsulated in this ERF.
flags uint32 Bit flags

Flags:

  • 0x00000001 (bit 0) : Unknown
  • 0x000000F0 (bits 4 - 7) : Encryption scheme
  • 0xE0000000 (bits 29 - 31) : Compression scheme

Encryption scheme: (flags >> 4) & 0xF

  • 0 : None
  • 1 : XOR
  • 2 : Blowfish
  • 3 : Blowfish (Dragon Age 2 only)
  • Any other value is invalid.

Compression scheme: (flags >> 29) & 0x7

  • 0 : None
  • 1 : Bioware Zlib (Dragon Age 2 only)
  • 2 : Unknown (Dragon Age 2 only)
  • 3 : Unknown (Dragon Age 2 only)
  • 7 : Headerless Zlib (Dragon Age 2 only)
  • Any other value is invalid.
moduleId uint32 This id is used to look up the password for the ERF when encryption is present, for example, DLC.
passwordDigest byte[16] MD5 sum of password (as a string).
stringTable char[stringTableSize] Zero-padded strings referenced by nameOffset in TOC entries. Strings are stored as ASCII. Note that not all TOC entries have to reference an entry in the string table.

Table of Contents

Name Type / Size Info
toc entry[fileCount]

Entry

Name Type / Size Info
nameOffset int32 Offset in stringTable of the file name for this entry. -1 if none.
nameHash uint64 FNV64 hash of lowercased file name, including path and extension.
typeHash uint32 FNV32 hash of lowercased file extension.
offset uint32 Offset to entry file data, from start of ERF file.
packedSize uint32 Packed length of file data.
unpackedSize uint32 Unpacked length of file data.

File Data

Encryption

When the appropriate flags are set in the header, a digest of the password will be present. File data will be encrypted depending on what scheme is specified.

You may not extract such third party ERF files unless you have permission to do so. This is provided only for purposes when you want to encrypt your own ERF files.

Blowfish

File data will be encrypted using Blowfish in ECB.

These instructions only apply to encryption scheme #2.

To encrypt:

To decrypt:

XOR

Much of the process for protecting data with XOR is the same as for Blowfish.

To encrypt:

To decrypt:

Compression

Compression is not supported by Dragon Age: Origins.

Compression is supported by Dragon Age 2.

Note that if encryption is enabled:

Bioware Zlib

File data is compressed with zlib, with a custom 1-byte (commonly observed as 0xF9) header (vs the normal 2-byte zlib header).

The upper 4 bits of the header byte represent the window bits. The lower 4 bits are currently unknown.

Headerless Zlib

File data is compressed with zlib, the normal 2-byte zlib header is omitted.

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