PCC File Format

BioWare stores a majority of game resources inside their own proprietary, compressed Mass Effect Package (PCC) files. This article covers the uncompressed and compressed structure of PCCs, along with the correlation between file nomenclature and what game resources they store.

Compressed Structure

If the file is compressed, the tables and data are segmented into chunks, each of which contains a variable number of compressed blocks.

Schematic representation of the compressed PCC file structure

Chunks Header

Chunks are preceded by a common header, which contains information about the chunks. The chunks header is 16 bytes in size.

Bytes	Description
4	Int32 Uncompressed Offset
4	Int32 Uncompressed Size
4	Int32 Compressed Offset
4	Int32 Compressed Size

Chunk Header

Each chunk has a header containing information about the raw compressed data contained in block form. The chunk header is also 16 bytes in size. The number of blocks a chunk has can be calculated by dividing the chunk uncompressed size through the block size.

Bytes	Description
4	Int32 Magic Number
4	Int32 Block Size
4	Int32 Compressed Size
4	Int32 Uncompressed Size

Block Header

Each block also has a header. The block header is 8 bytes in size.

Bytes	Description
4	Int32 Compressed Size
4	Int32 Uncompressed Size

Uncompressed Structure

All PCC files are divided into five parts: header, name table, import table, export table and data objects.

Schematic representation of the uncompressed PCC file structure

File Header

The File Header contains basic information about the structure of the PCC. Below is an example extracted from AreaMap_CitHub_Camps.pcc:

Block (hex)	Bytes (dec)	Description
0-3	4	Magic Number (0x9E2A83C1)
4-7	4	Version (0xC202AC = 12714668d = 194/684)
8-B	4	0x67C
C-F	4	0xFFFFFFFB = 5
10-19	10	0x4E006F006E006500 (N.o.n.e...)
1A-1D	4	Package Flags (0x8088000D = 2156396557d)
1E-21	4	0x0
22-25	4	Name Count (0x23 = 25d)
26-29	4	Pointer to Name Table (0x8E = 142d)
2A-2D	4	Export Count (0x6 = 6d)
2E-31	4	Pointer to Export Table (0x4c8 = 1224d)
32-35	4	Import Count (0x5 = 5d)
36-39	4	Pointer to Import Table (0x43C = 1084h)
3A-3D	4	0x664 = 1636d
3E-41	4	0x67C = 1660h
42-45	4	0x0
46-49	4	0x0
4A-4D	4	0x0
4E-51	4	GUID (0x1241956A = 306287978d)
52-55	4	GUID (0x48ECB3A7 = 1223472039d)
56-59	4	GUID (0x8EDAE68B = 2396710539d)
5A-5D	4	GUID (0xB945722C = 3108336172d)
5E-61	4	Generations (0x1)
62-65	4	Export Count (0x6 = 6d)
66-69	4	Name Count (0x23 = 35d)
6A-6D	4	0x0 = 0d
6E-71	4	Engine (0x18EF = 6383d)
72-75	4	0x3006B = 196715d
76-79	4	0x15330000 = 355663872d
7A-7D	4	0x8AA0000 = 145358848d
7E-81	4	Compression Flag (0x0 or 0x1)
82-85	4	Chunk Count (0x0 or 0x1)

Name Table

The Name Table contains any name found inside the package (import classes, exports, and export properties, for example. Each name follows this structure:

Bytes	Description
4	Int32 Count
Count * (-1)	Each char as WCHAR

Import Table

The Import Table contains all classes and objects imported by the PCC. Each entry is 28 bytes in size:

Bytes	Description
4	Int32 Package Name (entry in Name Table)
4	Unknown
4	Int32 Class Name (entry in Name Table)
4	Unknown
4	Int32 Link
4	Int32 Import Name (entry in Name Table)
4	Unknown

Export Table

The Export Table contains all objects stored in the package. Each export can vary in size.

Bytes	Description
4	Int32 Package Name (entry in Name Table)
4	Unknown
4	Int32 Link
4	Int32 Class Name (entry in Name Table)
4	Unknown
4	Int32 Data Size
4	Int32 Data Offset
4	Unknown
4	Int32 Count
20 + (Count * 4)	Unknown

Edited PCC Structure

When PCCs are edited, all new data is appended onto the end of the file, first new data objects followed by new lists. When using the "Alt. Save" function of PCCEditor2, the data is instead placed into the same location as the original export. The following data may be byte-shifted as a result. It is preferred to use the standard appending method.

Nomenclature + Contents

All PCCs follow various naming conventions that specify the game content they store. The tables below summarize these conventions.

Prefix	Description
BioA	Contain most level content, textures, meshes, etc. Rarely, there will be dialogues and related kismet sequences in these files.
BioD	Contain a majority of plot-related game content. This includes dialogues, cutscenes, matinee tracks, camera actors and scene staging, animation data, FaceFX data, kismet sequence objects, VFX content, GAW triggers, achievement triggers, and much more. There are also meshes/materials/effects in these files and there can be textures, as well. BioD PCC files tend to come in "partners," a main PCC accompanied by a localized version that contains all dialogue-related content.
BioG	Human male and female meshes and materials for faces, hair, scalps, clothing, and armor. This includes Shepard.
BioH	Hench/Squadmate-specific files. Contain meshes, materials, effects, combat AI, and more.
BioP	These are key files. They control very basic things like level streaming, henchmen loading/location/availability, player relocation within a level, and more.

BioA, BioD, and BioP files are organized by plot mission and/or location:

Abbreviation	Description
Cat001	From Ashes DLC
Cat002	Priority: Thessia
Cat003	Priority: Citadel II (the Coup)
Cat004	Priority: Cerberus HQ (Cronos Station)
CerJcb	Arrae: Ex-Cerberus Scientists
CerMir	Priority: Horizon
Cit001/2/3/4	Citadel DLC Missions
CitApt	Citadel Apartment (Citadel DLC)
CitCas	Silver Coast Casino (Citadel DLC)
CitSim	Armax Arsenal Arena (Citadel DLC)
CitHub	Citadel Station
CitSam	Kallini: Ardat-Yakshi Monastery
End001	Priority: Earth (standard ending)
End002	ME3 Extended Cut
Gth001	Priority: Perseus Veil & Geth Dreadnought
Gth002	Priority: Rannoch
GthLeg	Rannoch: Geth Fighter Squadrons
GthN7A	Rannoch: Admiral Koris
Kro001	Priority: Sur'Kesh
Kro002	Priority: Tuchanka
KroGar	Priority: Palaven
KroGru	Attican Traverse: Krogan Team
KroN7a	Tuchanka: Turian Platoon
KroN7b	Tuchanka: Bomb
Lev001/2/3/4	Leviathan DLC
MPCer	N7: Cerberus Lab (Glacier)
MPDish	N7: Communication Hub (Dagger)
MPNov	N7: Cerberus Fighter Base (White)
MPRctr	N7: Fuel Reactors (Reactor)
MPSlum	N7: Cerberus Abductions (Ghost)
MPTwr	N7: Cerberus Attack (Giant)
Nor	Normandy Ship
Omg000/1/2A/3/4	Omega DLC Missions
OmgHub	Omega Station (Omega DLC)
OmgJck	Grissom Academy: Emergency Evacuation
ProEar	Prologue: Earth
ProMar	Priority: Mars