BCSTM
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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.
Header
| 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:
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| X | X | DSP ADPCM Info Entries |
If encoding is IMA ADPCM:
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| X | X | IMA ADPCM Info Entries |
The info block is aligned to 0x20 bytes.
Encoding
| VALUE | DESCRIPTION |
|---|---|
| 0 | PCM8 |
| 1 | PCM16 |
| 2 | DSP ADPCM |
| 3 | IMA ADPCM |
Stream Info
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 1 | Encoding |
| 0x001 | 1 | Loop (0 = don't loop, 1 = loop) |
| 0x002 | 1 | Channel Count |
| 0x003 | 1 | Padding |
| 0x004 | 4 | Sample Rate |
| 0x008 | 4 | Loop Start Frame |
| 0x00C | 4 | Loop End Frame |
| 0x010 | 4 | Sample Block Count |
| 0x014 | 4 | Sample Block Size |
| 0x018 | 4 | Sample Block Sample Count |
| 0x01C | 4 | Last Sample Block Size |
| 0x020 | 4 | Last Sample Block Sample Count |
| 0x024 | 4 | Last Sample Block Padded Size |
| 0x028 | 4 | Seek Data Size |
| 0x02C | 4 | Seek Interval Sample Count |
| 0x030 | 8 | Sample Data Reference (Offset relative to Data Block Data field) |
Track Info
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 1 | Volume |
| 0x001 | 1 | Pan |
| 0x002 | 2 | Padding |
| 0x004 | 8 | Channel Index Byte Table Reference (Offset relative to Volume field) |
| 0x00C | X | Channel Index Byte Table (Padded to 4 bytes) |
Byte Table
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 4 | Count |
| 0x004 | Count | Elements |
Channel Info
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 8 | ADPCM Info Reference (Offset relative to this field) |
DSP ADPCM Info
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 32 | Param |
| 0x020 | 6 | Context |
| 0x026 | 6 | Loop Context |
| 0x02C | 2 | Padding |
DSP ADPCM Param
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 32 | 16-bit Coefficients |
DSP ADPCM Context
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 1 | 4-bit Predictor + 4-bit Scale |
| 0x001 | 1 | Reserved |
| 0x002 | 2 | Previous Sample |
| 0x004 | 2 | Second Previous Sample |
IMA ADPCM Info
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 4 | Context |
| 0x004 | 4 | Loop Context |
IMA ADPCM Context
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 2 | Data |
| 0x002 | 1 | Table Index |
| 0x003 | 1 | Padding |
Seek Block
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 8 | Block Header |
| 0x008 | Block Header Size Value - 8 | Data |
The seek block is aligned to 0x20 bytes.
Data Block
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 8 | Block Header |
| 0x008 | Block Header Size Value - 8 | Data |
The data block is aligned to 0x20 bytes, as well as the data field's actual sample data.
Reference Table
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 4 | Count |
| 0x004 | Count * 8 | References (Offsets relative to Count field) |
Sized Reference
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 8 | Reference |
| 0x008 | 4 | Size |
Reference
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 2 | Type ID |
| 0x002 | 2 | Padding |
| 0x004 | 4 | Offset ("null" = 0xFFFFFFFF) |
Reference Types
| ID | TYPE |
|---|---|
| 0x0100 | Byte Table |
| 0x0101 | Reference Table |
| 0x0300 | DSP ADPCM Info |
| 0x0301 | IMA ADPCM Info |
| 0x1F00 | Sample Data |
| 0x4000 | Info Block |
| 0x4001 | Seek Block |
| 0x4002 | Data Block |
| 0x4100 | Stream Info |
| 0x4101 | Track Info |
| 0x4102 | Channel Info |
Tools
The following tools can play BCSTMs and convert them to other formats:
- Isabelle Sound Editor
- vgmstream
- Every File Explorer