BCWAV

2017-11-04T12:29:38Z

1icri: Clarify Banner CWAV limits and the symptoms of exceeding the limit.

[[Category:File formats]]
This document is about the format of Banner's CTR Wave files (BCWAV).

The structure is very similar to Microsoft's Wave file.

Banner CWAV total channels must be 2, and the length of the audio must be 3 seconds or less, otherwise the sound will play incorrectly (beeping/clicking) or the model may fail to load.

=== 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).

=== Header ===

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 4 || Magic (CWAV)
|-
| 0x004 || 2 || Endianness (0xFEFF = little, 0xFFFE = big)
|-
| 0x006 || 2 || Header Size (0x40 due to [[#Info Block|Info Block]] alignment)
|-
| 0x008 || 4 || Version (0x02010000)
|-
| 0x00C || 4 || File Size
|-
| 0x010 || 2 || Number of Blocks (2)
|-
| 0x012 || 2 || Reserved
|-
| 0x014 || 12 || [[#Info Block|Info Block]] [[#Sized Reference|Sized Reference]] (Offset relative to start of file)
|-
| 0x020 || 12 || [[#Data Block|Data Block]] [[#Sized Reference|Sized Reference]] (Offset relative to start of file)
|}

=== Block Header ===

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 4 || Magic
|-
| 0x004 || 4 || Size
|}

==== Block Types ====

{| class="wikitable" border="1"
|-
! MAGIC !! TYPE
|-
| INFO || [[#Info Block|Info Block]]
|-
| DATA || [[#Data Block|Data Block]]
|}

=== Info Block ===

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 8 || [[#Block Header|Block Header]]
|-
| 0x008 || 1 || [[#Encoding|Encoding]]
|-
| 0x009 || 1 || Loop (0 = don't loop, 1 = loop)
|-
| 0x00A || 2 || Padding
|-
| 0x00C || 4 || Sample Rate
|-
| 0x010 || 4 || Loop Start Frame
|-
| 0x014 || 4 || Loop End Frame
|-
| 0x018 || 4 || Reserved
|-
| 0x01C || X || [[#Channel Info|Channel Info]] [[#Reference Table|Reference Table]]
|-
| X || X || [[#Channel Info|Channel Info]] Entries
|}

If encoding is DSP ADPCM:

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| X || X || [[#DSP ADPCM Info|DSP ADPCM Info]] Entries
|}

If encoding is IMA ADPCM:

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| X || X || [[#IMA ADPCM Info|IMA ADPCM Info]] Entries
|}

The info block is aligned to 0x20 bytes.

==== Encoding ====

{| class="wikitable" border="1"
|-
! VALUE !! DESCRIPTION
|-
| 0 || PCM8
|-
| 1 || PCM16
|-
| 2 || DSP ADPCM
|-
| 3 || IMA ADPCM
|}

==== Channel Info ====

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 8 || Samples [[#Reference|Reference]] (Offset relative to [[#Data Block|Data Block]] Data field)
|-
| 0x008 || 8 || ADPCM Info [[#Reference|Reference]] (Offset relative to Samples [[#Reference|Reference]] field)
|-
| 0x010 || 4 || Reserved
|}

===== DSP ADPCM Info =====

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 32 || [[#DSP ADPCM Param|Param]]
|-
| 0x020 || 6 || [[#DSP ADPCM Context|Context]]
|-
| 0x026 || 6 || Loop [[#DSP ADPCM Context|Context]]
|-
| 0x02C || 2 || Padding
|}

====== DSP ADPCM Param ======

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 32 || 16-bit Coefficients
|}

====== DSP ADPCM Context ======

{| class="wikitable" border="1"
|-
! 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 =====

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 4 || [[#IMA ADPCM Context|Context]]
|-
| 0x004 || 4 || Loop [[#IMA ADPCM Context|Context]]
|}

====== IMA ADPCM Context ======

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 2 || Data
|-
| 0x002 || 1 || Table Index
|-
| 0x003 || 1 || Padding
|}

=== Data Block ===

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 8 || [[#Block Header|Block Header]]
|-
| 0x008 || [[#Block Header|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 ===

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 4 || Count
|-
| 0x004 || Count * 8 || [[#Reference|References]] (Offsets relative to Count field)
|}

=== Sized Reference ===

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 8 || [[#Reference|Reference]]
|-
| 0x008 || 4 || Size
|}

=== Reference ===

{| class="wikitable" border="1"
|-
! OFFSET !! SIZE !! DESCRIPTION
|-
| 0x000 || 2 || Type ID
|-
| 0x002 || 2 || Padding
|-
| 0x004 || 4 || Offset ("null" = 0xFFFFFFFF)
|}

==== Reference Types ====

{| class="wikitable" border="1"
|-
! ID !! TYPE
|-
| 0x0300 || [[#DSP ADPCM Info|DSP ADPCM Info]]
|-
| 0x0301 || [[#IMA ADPCM Info|IMA ADPCM Info]]
|-
| 0x1F00 || [[#Data_Block|Sample Data]]
|-
| 0x7000 || [[#Info Block|Info Block]]
|-
| 0x7001 || [[#Data Block|Data Block]]
|-
| 0x7100 || [[#Channel Info|Channel Info]]
|}

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BCWAV