File Formats

ARC

File Formats

This page documents the format of ARC.

Overview #

ARC files are compressed files.

Found in manual files compressed with LZ-10

(more compression methods might be available).

Category:File formats

CTR Font Format #

.bcfnt files are bitmap fonts made for the 3ds. The system font uses this format too except the header is changed from CFNT to CFNU and all file offsets are changed to absolute in memory offsets.

CFNT Header #

Offset	Size	Description
0x00	0x04	Magic Header (either CFNT or CFNU or FFNT)
0x04	0x02	Endianness (0xFEFF = little, 0xFFFE = big)
0x06	0x02	Header Size
0x08	0x04	Version (observed to be 0x03000000)
0x0C	0x04	File size (the total)
0x10	0x04	Number of “blocks” to read

FINF Header #

Version 3 (BCFNT) #

Offset	Size	Description
0x00	0x04	Magic Header (FINF)
0x04	0x04	Section Size
0x08	0x01	Font Type
0x09	0x01	Line Feed
0x0A	0x02	Alter Char Index
0x0C	0x03	Default Width (3 bytes: Left, Glyph Width, Char Width)
0x0F	0x01	Encoding
0x10	0x04	TGLP Offset
0x14	0x04	CWDH Offset
0x18	0x04	CMAP Offset
0x1C	0x01	Height
0x1D	0x01	Width
0x1E	0x01	Ascent
0x1F	0x01	Reserved

Version 4 (BFFNT) #

Offset	Size	Description
0x00	0x04	Magic Header (FINF)
0x04	0x04	Section Size
0x08	0x01	Font Type
0x09	0x01	Height
0x0A	0x01	Width
0x0B	0x01	Ascent
0x0C	0x02	Line Feed
0x0E	0x02	Alter Char Index
0x10	0x03	Default Width (3 bytes: Left, Glyph Width, Char Width)
0x13	0x01	Encoding
0x14	0x04	TGLP Offset
0x18	0x04	CWDH Offset
0x1C	0x04	CMAP Offset

TGLP Header #

Version 3 (BCFNT) #

Offset	Size	Description
0x00	0x04	Magic Header (TGLP)
0x04	0x04	Section Size
0x08	0x01	Cell Width
0x09	0x01	Cell Height
0x0A	0x01	Baseline Position
0x0B	0x01	Max Character Width
0x0C	0x04	Sheet Size
0x10	0x02	Number of Sheets
0x12	0x02	Sheet Image Format 0-13: (RGBA8, RGB8, RGBA5551, RGB565, RGBA4, LA8, HILO8, L8, A8, LA4, L4, A4, ETC1, ETC1A4)
0x14	0x02	Number of columns
0x16	0x02	Number of rows
0x18	0x02	Sheet Width
0x1A	0x02	Sheet Height
0x1C	0x04	Sheet Data Offset

Version 4 (BFFNT) #

Offset	Size	Description
0x00	0x04	Magic Header (TGLP)
0x04	0x04	Section Size
0x08	0x01	Cell Width
0x09	0x01	Cell Height
0x0A	0x01	Number of Sheets
0x0B	0x01	Max Character Width
0x0C	0x04	Sheet Size
0x10	0x02	Baseline Position
0x12	0x02	Sheet Image Format 0-13: (RGBA8, RGB8, RGBA5551, RGB565, RGBA4, LA8, HILO8, L8, A8, LA4, L4, A4, ETC1, ETC1A4)
0x14	0x02	Number of Sheet columns
0x16	0x02	Number of Sheet rows
0x18	0x02	Sheet Width
0x1A	0x02	Sheet Height
0x1C	0x04	Sheet Data Offset

CMAP Header #

Offset	Size	Description
0x00	0x04	Magic Header (CMAP)
0x04	0x04	Section Size
0x08	0x02	Code Begin
0x0A	0x02	Code End
0x0C	0x02	Mapping Method (0 = Direct, 1 = Table, 2 = Scan)
0x0E	0x02	Reserved?
0x10	0x04	Next CMAP Offset

Depending on the mapping method the next bytes are read like so:

BCMA

File Formats

BCMA is the file format used for the electronic manuals on the Nintendo 3DS. It presumably stands for Binary CTR Manual.

Region and language codes #

In several places, three letter uppercase region codes and two letter lowercase language codes are used. These will be indicated by the italic placeholders REG and la respectively on this page.

The following region and language codes are known:

Region code	Region	Language code	Language
EUR	Europe	de	German
		en	British English
		fr	French
		es	Spanish
		it	Italic
		nl	Dutch
		pt	Portuguese
		ru	Russian
JPN	Japan	ja	Japanese

Top-level archive overview #

A BCMA file is a regular, uncompressed DARC archive which contains a set of LZ10-compressed DARC archives. These subarchives contoin files containing either textures in the BCLIM format or metadata and manual pages in the binary CLYT format.

BCSAR

File Formats

The BCSAR (Binary CTR Sound ARchive) format is the 3DS’s equivalent of the Wii’s BRSAR format. They’re not the same structures, though, but they do have the same purpose.

BCSAR are located in the RomFS, this is usually stored under “romfs:/sound/.bcsar”. This contains various audio formats, such as CSTM, CWSD, CSEQ, and CWAV.

BCSAR Header #

OFFSET	SIZE	DESCRIPTION
0x0	0x4	MAGIC “CSAR”
0x4	0x2	Byte order mark (0xFEFF = Big Endian, 0xFFFE = Little Endian)
0x6	0x2	Length of BCSAR header
0x8	0x4	Version
0xC	0x4	Length of the entire BCSAR (starting from 0x0)
0x10	0x4	Amount of main partitions in the BCSAR [STRG + INFO + FILE = 0x03 (= 3)]
0x14	0x4	STRG partition reference ID? (Always 0x2000)
0x18	0x4	Location of STRG partition
0x1C	0x4	Length of STRG partition
0x20	0x4	INFO partition reference ID? (Always 0x2001)
0x24	0x4	Location of INFO partition
0x28	0x4	Length of INFO partition
0x2C	0x4	Main FILE partition reference ID? (Always 0x2002)
0x30	0x4	Location of main FILE partition
0x34	0x4	Length of main FILE partition
0x38	0x4	Reserved for 4th main partition location?
0x3C	0x4	Reserved for 4th main partition length?

Partitions #

STRG #

STRG contains the names of the audio files in the BCSAR.

BCSTM

File Formats

This document is about the format of CTR Streams (CSTM).

Overview #

The structure is similar to that of a BCWAV, with a few differences, such as its different INFO block format, the addition of a SEEK block, and the organization of the DATA block samples into blocks.

These files are either found in rom:\sound\stream\ or they can be inside of a CSAR.

OFFSET	SIZE	DESCRIPTION
0x000	4	Magic (CSTM)
0x004	2	Endianness (0xFEFF = little, 0xFFFE = big)
0x006	2	Header Size (0x40 due to Info Block alignment)
0x008	4	Version (0x02000000)
0x00C	4	File Size
0x010	2	Number of Blocks (3)
0x012	2	Reserved
0x014	12	Info Block Sized Reference (Offset relative to start of file)
0x020	12	Seek Block Sized Reference (Offset relative to start of file)
0x02C	12	Data Block Sized Reference (Offset relative to start of file)

Block Header #

OFFSET	SIZE	DESCRIPTION
0x000	4	Magic
0x004	4	Size

Block Types #

MAGIC	TYPE
INFO	Info Block
SEEK	Seek Block
DATA	Data Block

Info Block #

OFFSET	SIZE	DESCRIPTION
0x000	8	Block Header
0x008	8	Stream Info Reference (Offset relative to this field)
0x010	8	Track Info Reference Table Reference (Offset relative to Stream Info Reference field)
0x018	8	Channel Info Reference Table Reference (Offset relative to Stream Info Reference field)
0x020	56	Stream Info
0x058	X	Track Info Reference Table
X	X	Channel Info Reference Table
X	X	Track Info Entries
X	X	Channel Info Entries

If encoding is DSP ADPCM:

BCWAV

File Formats

This document is about the format of Binary CTR Wave files (BCWAV). The structure is very similar to Microsoft’s Wave file.

Overview #

Microsoft’s WAV structure is RIFF Header which defines the data inside which is WAVE, then the media player expects a “fmt " chunk and a “data” chunk. Nintendo’s format uses a CWAV header (no need for a general structure for media, only wave), which points to an INFO struct (the equivalent to fmt) and a DATA struct (the equivalent to data).

CBMD

File Formats

CBMD - CTR Banner Model Data

This page describes the format used for banners’ models. These are stored in CXI ExeFS:/banner and optionally in extdata exbanner. CBMD is a container file for CGFX blocks. This is used for banners of titles you see in the home menu. BNR used for the app banners in the CXI/exbanner is the same as CBMD with CWAV at the end.

CBMD Header #

Offset	Length	Description
0x0	0x4	Magic “CBMD”
0x4	0x4	Zero
0x8	0x4	Offset for common CGFX
0xc	0x34	Optional offsets for region/language specific CGFX
0x40	0x44	Padding?
0x84	0x4	BCWAV offset

The common CGFX is used if the CGFX offset for the system region/language is zero. Those optional offsets can be used in extdata exbanner, but separate CBMD banner files for each region/language can be used as well.

CCI

File Formats

Overview #

NCSD images start with a NCSD header, followed by up to a maximum of 8 partitions according to spec. The first partition(NCCH 0) usually starts at 0x4000, this is generally the main NCCH executable. The following info on partitions 1, 2, and 7 are only valid for .CCI. The second partition(NCCH 1) contains the game “Manual”(title ID for the .CXI containing the Manual always starts with ‘0005’). The third partition(NCCH 2) contains the download play “Child”(The title ID for the NCCH containing the Child always starts with ‘0006’). The eighth block(NCCH 7) contains “Update Data”(The title ID for the NCCH containing the Update Data always starts with ‘8000’) The format of partitions can be determined from the partition FS flags, while the contents can be determined from the partitions flags.

CGFX

File Formats

CGFX is a container format used to store graphics resources. It can contain 3D models, textures and animation data.

CGFX #

CGFX header :

Offset	Length	Description
0x0	0x4	Magic “CGFX”
0x4	0x2	Byte order mark: FFFE (little endian) or FEFF (big endian)
0x6	0x2	CGFX header size
0x8	0x4	Revision
0xC	0x4	File size (bytes)
0x10	0x4	Number of entries

A typical CGFX file contains two main entries, beginning directly after the CGFX header: DATA and IMAG.

CIA

File Formats

Overview #

CIA stands for CTR Importable Archive. This format allows the installation of titles to the 3DS. CIA files and titles on Nintendo’s CDN contain identical data. As a consequence, valid CIA files can be generated from CDN content. This also means CIA files can contain anything that titles on Nintendo’s CDN can contain.

Under normal circumstances CIA files are used where downloading a title is impractical or not possible. Such as distributing a Download Play child, or installing forced Gamecard updates. Those CIA(s) are stored by the titles in question, in an auxiliary CFA file.

CLAN Format

File Formats

CLAN (.bclan) is the layout animation format used on the 3DS. It stands for (Binary) CTR Layout Animation, and is similar to the RLAN format used on the Wii.

Offset	Size	Type	Description
0x00	0x4	String	Signature (CLAN)
0x04	0x2	UInt16	Byte Order Mark
0x06	0x2	UInt16	Header Length
0x08	0x4	UInt32	Revision
0x0C	0x4	UInt32	File Size
0x10	0x4	UInt32	Nr Sections

pat1 (Pattern 1) #

Offset	Size	Type	Description
0x00	0x4	String	Signature (pat1)
0x04	0x4	UInt32	Section Size
0x08	0x4	UInt32	Flags?
0x0C	0x4	UInt32	?
0x10	0x4	Int32	?
0x14	0x4	UInt32	?
0x18	0x10	String	Pattern name

pai1 (Pattern Instruction? 1) #

Offset	Size	Type	Description
0x00	0x4	String	Signature (pai1)
0x04	0x4	UInt32	Section Size
0x08	0x4	UInt32	?
0x0C	0x4	UInt32	Flags?
0x10	0x4	UInt32	Nr entries?
0x14	0x4	UInt32	Entries offset (relative to pai1)

Instruction? entry #

Offset	Size	Type	Description
0x00	0x14	String	Target panel name
0x14	0x4	UInt32	Flags?
0x18	0x4	UInt32	Animation entry offset (relative to entry)
0x1C	0x4	UInt32	? (if flag bit 1 is set)

Animation entry #

0x00

0x4

String

Animation type

CLYT Format

File Formats

CLYT (.bclyt) is the layout format used on the 3DS. It stands for (Binary) CTR Layout, and is similar to the RLYT format used on the Wii.

Offset	Size	Type	Description
0x00	0x4	String	Signature (CLYT)
0x04	0x2	UInt16	Byte Order Mark
0x06	0x2	UInt16	Header Length
0x08	0x4	UInt32	Revision
0x0C	0x4	UInt32	File Size
0x10	0x2	UInt16	Nr Sections
0x12	0x2	UInt16	Padding

lyt1 (Layout 1) #

0x00

0x4

String

Signature (lyt1)

0x04

0x4

UInt32

Section Size

0x08

0x4

UInt32

Origin type

CRO0

File Formats

CRO with extension .cro is used for “DLLs”. CRS with extension .crs is in the same format of CRO but storing the symbol information of the static module (the main application). The end of the file is aligned to a 0x1000-byte boundary with 0xCC bytes.

The first hash-table entry hashes the 0x100-byte header following the hash-table. The following hash-table entries hash the sections specified in the header.

When the RO module loads the entire CRO into process memory(mapped in the 0x00100000-0x04000000 region), it modifies the mapped CRO data. The magic field is also changed to “FIXD” if fix level is not 0.

CRR0

File Formats

Offset	Size	Description
0x0	0x4	Magic “CRR0”
0x4	0x4	Reserved
0x8	0x4	Next loaded CRR (Must be zero in file, set by RO during loading)
0xC	0x4	Previous loaded CRR (Must be zero in file, set by RO during loading)
0x10	0x4	Debug Info Offset
0x14	0x4	Debug Info Size
0x18	0x8	Reserved
0x20	0x4	UniqueID Mask
0x24	0x4	UniqueID Pattern
0x28	0x18	Reserved
0x40	0x100	RSA-2048 modulo
0x140	0x100	RSA-2048 signature signed by Nintendo, starting at offset 0x20 with size 0x120
0x240	0x100	RSA-2048 signature verified with the above modulo, over the data starting at 0x340 with the size from 0x358
0x340	0x4	Process UniqueID<<8, from the ProgramID
0x344	0x4	Size of the whole CRR0 file
0x348	0x8	Reserved
0x350	0x4	Hash-table Offset
0x354	0x4	Total hashes in the hash-table
0x358	0x4	Offset to the plain region containing text tags, from the process NCCH
0x35C	0x4	Size of plain region
0x360		SHA-256 hash-table

Each hash stored in the hash-table is over the corresponding executable CRO0 hash-table.

CSU

File Formats

NCSD

CTPK

File Formats

CTPK - CTR Texture PacKage

CTPK is a container file for one or multiple textures that are in various formats readable by the 3ds system. Offsets are relative to the beginning of the header section unless specified.

CTPK Header #

Offset	Length	Description
0x0	0x4	Magic “CTPK”
0x4	0x2	Version?
0x6	0x2	Number of Texture Entries
0x8	0x4	Texture Data section offset
0xC	0x4	Texture Data section size
0x10	0x4	Hash section offset
0x14	0x4	Conversion Info section offset
0x18	0x8	Padding

Texture Info Entry #

The Header block is followed by a texture info entry for each texture in the container. This block is usually followed by the bitmap size arrays and then the file paths. 0x20 byte aligned.

CXI

File Formats

NCCH#cxi

DARC

File Formats

This page documents the format of DARC.

Overview #

DARC files are archives. Containers of files.

This is very similiar to NARC (the DS archives).

ARC header #

Offset	Size	Type	Description
0x000	4	char[4]	Magic Number ‘darc’
0x004	2	uint16	Endianess (=0xFFFE: Little)
0x006	2	uint16	Header’s length
0x008	4	uint32	Version
0x00C	4	uint32	File’s length
0x010	4	uint32	File table offset (from the beginning of the file)
0x014	4	uint32	File table length
0x018	4	uint32	Files data offset

File table #

The file table starts at 0x01C.

DSP Binary

File Formats, DSP

0x0

0x100

RSA Signature over bytes 0x100-0x300

0x100

Magic ('DSP1')

0x104

DSP binary size

0x108

Memory layout (bits 0-7: Program ram, 8-15: Data ram). Each bit represents a memory region. The region is always 0x8000 bytes in size (the first region starts at 0x1FF00000; the next is a 0x1FF08000 and so on). The HW registers for DSP memory configuration are CFG11_SHAREDWRAM_32K_DATA and CFG11_SHAREDWRAM_32K_CODE, located at physical address 0x10140000 (mapped to 0x1EC40000).

0x10C

0x10D

Special segment memory type (0=1=0x1FF00000(Program ram)+,2=0x1FF40000(Data ram)+)

0x10E

Num segments (must be 1-10)

0x10F

Flags:

MPO

File Formats

Overview #

MPO = Multi-Picture Object

Document describing the file format used in mpo files: 🔗 http://www.cipa.jp/std/documents/e/DC-007_E.pdf

Nintendo uses a common format for its 3D pictures. MPO is basically two JPG files concatenated in one file. The two JPG files has an EXIF data structure in their headers (This was developed by CIPA).

EXIF is a standard that specifies the formats for images, sound, and ancillary tags used by digital cameras (including smartphones), scanners and other systems handling image and sound files recorded by digital cameras. 🔗 1

NCCH

File Formats

The following text tries to document the structure of the NCCH (Nintendo Content Container Header) container format. This format is used to store the content of any installed title.

Overview #

There are two known NCCH container specializations used on the 3DS, “executable” and “non-executable”, officially known as CXI and CFA, respectively.

CXI #

The CXI (CTR Executable Image) specialization of the NCCH container contains executable code, which runs on a single ARM11 core.

NCSD

File Formats

This page documents the format of NCSD.

Overview #

There are two known specialisations of the NCSD container format. The CTR Cart Image (CCI) format and the 3DS’ raw NAND format. CCI is the format of game ROM images.

CTR System Update (CSU) is a variant of CCI, where the only difference is in the file extension. This is used with developer System Updates and associated Tools.

NCSD images start with a NCSD header, followed by up to a maximum of 8 NCCH partitions.

Nintendo 3DS Sound

File Formats, Nintendo Software

Nintendo 3DS Sound is the music playing and audio recording application that is included with all retail consoles.

Voice Recorder #

Like its predecessor for the DSi, up to 10-second recordings can be stored, with limited integration of those with other software.

Practically speaking, the single page of internal storage is for DSi-mode software, and the 10 pages of SD card storage are for 3DS software (like Flipnote Studio 3D).

PSLB

File Formats

This page documents the format of PSLB.

Overview #

PSLB are data-interchange files like JSON or XML.

Offset	Size	Type	Description
0x000	4	char[4]	Magic Number ‘PSLB’
0x004	4	uint32	Unkown
0x008	4	uint32	Unkown
0x00C	4	uint32	Unkown

Data #

The data is constructed of 1 byte that represents what type of data follows

Value	Type
1	String
2	int32
3	float (4 byte)
4	Byte
5	Map
6	List

The string type is a combination of an uint32 for the length of the string followed by the characters of the string.

SARC

File Formats

SARC File Format #

.sarc files are similar to the ARC format with a slightly different structure.

File Format #

SARC Header #

Offset	Size	Description
0x00	0x04	Magic Bytes “SARC”
0x04	0x02	Header Length
0x06	0x02	Byte-order marker (0xFEFF = big, 0xFFFE = little)
0x08	0x04	File Length
0x0C	0x04	Data Offset (absolute)
0x10	0x04	Unknown (always 0x00000100)

SFAT Header #

Offset	Size	Description
0x00	0x04	Magic bytes “SFAT”
0x04	0x02	Header Length
0x06	0x02	Node Count
0x08	0x04	Filename Hash Multiplier (usually 0x65)

SFAT Node #

Offset	Size	Description
0x00	0x04	Name Hash
0x04	0x04	SFNT Filename Offset (relative to SFNT data section)
0x08	0x04	File Data Start (relative to SARC data start)
0x0C	0x04	File Data End (relative to SARC data end)

Node hashing function #

The node hash is calculated via:

SHBIN

File Formats

The SHBIN (SHader BINary) format is used to contain compiled and linked shader programs. These can include vertex shaders and geometry shaders. In commercial applications, SHBIN files can be found as standalone files with the extension .shbin, or within container formats like, for example, CGFX (with the extension .bcsdr). They are typically compiled from .vsh files, .gsh files, and sometimes .asm files.

A SHBIN’s structure starts with a binary header (DVLB), then a single program header (DVLP), then one or more executable headers DVLE(s). The binary header specifies the number and location of DVLEs. The program header specifies the generic parts of the shader (i.e. the shader program data, the operand descriptor data, and a filename symbol table). The executable headers specify the contextual details (i.e. entry point, constant values, debug symbols, etc). There may be multiple executable headers, so in this sense multiple shaders sharing the same program code can be stored in a single SHBIN. Hence for the following, note the distinction between “program” and “executable”.

Ticket

File Formats

Tickets are a format used to store an encrypted titlekey (using 128-Bit AES-CBC). With 3DS, the Ticket format was updated (now v1) from Wii/DSi format (v0).

Structure #

All of the data in the file is represented in Big Endian.


Offset	Size	Description
0x000	Y	Signature Data
Y	0x210	Ticket Data

Y denotes the total size of the “Signature Data” section and depends on the signature type.

Title Metadata

File Formats

Title metadata is a format used to store information about a title (installed title, DLC, etc.) and all its installed contents, including which contents they consist of and their SHA256 hashes.

🔗 Code is available by trap15 to parse the available information from the 3DS format of TMDs.

Structure #

All the data in the file represented in Big Endian, unless otherwise noted.


Offset	Size	Description
0x0	Y	Signature Data
Y	0xC4	Header
0xC4 + Y	0x24*64	Content Info Records.
0x9C4 + Y	0x30*ContentCount	Content Chunk Records.

Y denotes the total size of the “Signature Data” section and depends on the signature type.