BMG (File Format)

This page is in progress and may contain incomplete information or editor's notes.

BMG is a file format used to hold text in SMG1. This was replaced by the MSBT file format in SMG2. Unlike the messages in SMG2, SMG1 uses a single, region specific BMG file (Region/message.arc/message.bmg) to hold ALL text.

Format Specifications

Below you'll find helpful tables on how this file is structured in SMG1 and 3D All Stars, other games that use BMG might be different.

All char[] types are in ASCII encoding.

Header

Offset	Type	Description
0x0	char[4]	File magic. "MESG" for SMG1, "GSEM" for 3D All Stars.
0x4	char[4]	File magic. "bmg1" for SMG1. "1gmb" for 3D All Stars.
0x8	u32	FLW1 Section offset.
0x0C	u32	Section count.
0x10	u8	Unknown. Believed to be a definition of encoding in some games.
0x11	u8[15]	Padding.

Sections

All sections start with a section identifier.

Offset	Type	Description
0x0	char[4]	Magic. Relates to the Section Type it is.
0x4	u32	Section Size.

Depending on the Magic, the section can be one of the following types below.

INF1 Section

This section holds message information.

Offset	Type	Description
0x0	u16	Entry count.
0x2	u16	Entry size.
0x4	u8[4]	Padding.

Entries are structured as following:

Offset	Type	Description
0x0	u32	Message data offset.
0x4	u16	Camera ID.
0x6	u8	Sound ID.
0x7	u8	Camera type. (Normal = 0, Event = 1, None = 2)
0x8	u8	Talk type. (Normal = 0, Short = 1, Event = 2, Composite = 3, Flow = 4, Null = 5)
0x9	u8	Balloon type. (Normal = 0, Unk = 1, Call = 2, Fixed = 3, Signboard = 4, Info = 5, Icon = 6)
0xA	u8	Area ID.
0xB	u8	Index into the MessageAlreadyRead GameEventValue.

DAT1

This section contains null-terminated message data, encoded in BE UTF-16. These messages have custom tags, which the game interprets and replaces with the correct text/visuals.

Offset	Type	Description
0x0	wchar_t	Tag identifier. (Always 0x14)
0x2	u8	Tag size. (Including the identifier)
0x3	u8	Padding.
0x4	u16	Tag type.

Todo: Document tag types.

FLW1

This section holds flow information.

Offset	Type	Description
0x0	u16	Flow node count.
0x2	u16	Branch node count.
0x4	u8[4]	Padding.

All flow nodes have 8 bytes in total. The 1st byte defines flow type.

Offset	Type	Description
0x0	u8	Node type. (Text = 1, Condition = 2, Event = 3)
0x1	u8[7]	Text node data: Offset Type Description 0x1 u8 Unknown. 0x2 u16 Message ID. 0x4 u16 Next flow ID. 0x6 u8 Validity. (?) 0x7 u8 Unknown. Condition node data: Offset Type Description 0x1 u8 Unknown. 0x2 u16 Condition type. 0x4 u16 Condition argument. 0x6 u16 Branch node ID. If the condition is true, the game will branch into branch node ID. If the condition is false, the game will branch into branch node ID + 1. Event node data: Offset Type Description 0x1 u8 Event type. 0x2 u16 Branch node ID. 0x4 u32 Event argument.

This is followed by branch node IDs, an array of u16s that point to flow indices.

FLI1

The purpose of this section is unknown. This is not used/supported in SMG1/3D All Stars.

Offset	Type	Description
0x0	u16	Entry count.
0x2	u8	Entry size. (Always 8)
0x3	u8[5]	Padding.

This is followed by entries with the following structure:

Offset	Type	Description
0x0	u16	Unknown.
0x2	u8[2]	Padding.
0x4	u16	Unknown.
0x6	u8[2]	Padding.

Labels

SMG1/3D All Stars BMGs do not have labels inside them. Instead, message labels are set through messageid.tbl, a sorted BCSV file.

This .tbl file contains 2 fields:

• The MessageId (STRINGOFF) field that contains a label name.
• The Index (LONG) field that contains the label's respective message index.

Tools

The following tools can handle SMG1's BMG (some may have 3D All Stars support, but most don't.)

• Tomato (Can convert a BMG + the TBL file to a XML file and vise versa. Has 3D All Stars Support)
• Wiimms SZS Tools (wbmgt) (Can convert a BMG to a TXT file. High chance of crashing if you edit with this.)