Dn FT instrument format

Dn-FamiTracker Instrument format

• Last updated 2025-01-27
• Version 2.4

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File header

Data type	Unit size (bytes)	Repeat	Object/relevant variable in code	Description	Valid values	Notes
char[4]	4		INST_HEADER	Identifier string	FTI	Null-terminated string
unsigned int	4		INST_VERSION	Module version	2.4	Null-terminated string
char	1		m_pInstrumentManager->GetInstrument()->m_iType	Instrument type	enum inst_type_t	See table.
int	4		strlen() of m_pInstrumentManager->GetInstrument()->GetName()	Instrument name length	0 to CInstrument::INST_NAME_MAX.
char[]	Instrument name length		m_pInstrumentManager->GetInstrument()->GetName()	Instrument name

Instrument type value

Chip	Index
2A03	0x01
VRC6	0x02
VRC7	0x03
FDS	0x04
N163	0x05
S5B	0x06

Base instrument format

Data type	Unit size (bytes)	Repeat	Object/relevant variable in code	Description	Valid range	Notes	Present in instrument version
int	4		SEQ_COUNT	Sequence count	enum sequence_t	Number of defined sequence types. Volume, Arpeggio, Pitch, Hi-Pitch, Duty cycle	?
char	1	Per sequence count	CSeqInstrument::m_iSeqEnable[]	Sequence enable	0 to 1	0 = sequence is disabled, 1 = sequence is enabled	?
int	4	^	CSequence::m_iItemCount	Sequence item count	0 to MAX_SEQUENCE_ITEMS	Written only when sequence is enabled.	2.0+
int	4	^	CSequence::m_iLoopPoint	Sequence loop point	-1 to (m_iItemCount -1)	Written only when sequence is enabled	2.0+
int	4	^	CSequence::m_iReleasePoint	Sequence release point	-1 to (m_iItemCount -1)	Written only when sequence is enabled	2.0+
int	4	^	CSequence::m_iSetting	Sequence setting	seq_setting_t		2.2+
char[]	Sequence item count	^	CSequence::m_cValues[]	Sequence data			2.0+

Notes

• Information is based on CSeqInstrument::SaveFile()

2A03 instruments

Data type	Unit size (bytes)	Repeat	Object/relevant variable in code	Description	Valid range	Notes	Present in instrument version
CSeqInstrument	size of CSeqInstrument			See Base instrument format.
int	4		CInstrument2A03::GetSampleCount()	DPCM sample assignment count	0 to MAX_DSAMPLES
char	1	DPCM sample assignment count	Note	DPCM sample assignment note index	0 to NOTE_COUNT	Off by +1. Written only when a sample exists at that note.
char	1	^	CInstrument2A03::m_cSamples[Octave][Note]	DPCM sample assignment index	0 to MAX_DSAMPLES	If assignment is greater than MAX_DSAMPLES, it is not added.
char	1	^	CInstrument2A03::m_cSamplePitch[Octave][Note]	DPCM sample pitch	0x0 to 0xF	Written only when a sample exists at that note in FT 050b1+.
char	1	^	CInstrument2A03::m_cSampleDelta[Octave][Note]	DPCM delta offset of a given note	-1 to 0x7F	Versions before 2.4 will write no offset	2.4+
int	4		SampleCount	DPCM sample count	0 to MAX_DSAMPLES
int	4	DPCM sample count		DPCM sample index	0 to MAX_DSAMPLES - 1
int	4	^		DPCM sample name length	0 to MAX_NAME_SIZE - 1
char[]	DPCM sample name length	^		DPCM sample Name		Not null terminated.
int	4	^		DPCM sample size	Not bounded?
char[]	DPCM sample size	^		DPCM sample data		the code currently does not check for DPCM length.

Notes

• Information is based on CInstrument2A03::SaveFile()
• v2.4 adds DPCM delta settings.
• Only 72 notes are defined in version 1. Version 2+ has all 96 notes defined.
• In FamiTracker 0.5.0 beta, the DPCM format has been changed to only count notes with DPCM assignments.
• DPCM samples in a given module are limited to either MAX_DSAMPLES number of samples, or 256kiB total memory use
• If an identical DPCM sample in name and data is found, it will not be loaded

VRC6 instruments

• Same format as Base instrument format.
• Fifth sequence type is named Pulse Width.

Notes

• Information is based on CSeqInstrument::SaveFile()
• Similar to 2A03 instruments but with no special considerations for DPCM

VRC7 instruments

Data type	Unit size (bytes)	Repeat	Object/relevant variable in code	Description	Valid range	Notes	Present in instrument version
int	4		CInstrumentVRC7::m_iPatch	VRC7 patch number		Hardware patch number of the instrument.	2+
char[8]	8		CInstrumentVRC7::m_iRegs[]	Custom patch settings		Patch settings of hardware patch 0.	2+

Notes

• Information is based on CInstrumentVRC7::SaveFile()

FDS instruments

Data type	Unit size (bytes)	Repeat	Object/relevant variable in code	Description	Valid range	Notes	Present in instrument version
char[WAVE_SIZE]	WAVE_SIZE		CInstrumentFDS::m_iSamples[]	Wave data
char[MOD_SIZE]	MOD_SIZE		CInstrumentFDS::m_iModulation[]	Modulation table
int	4		CInstrumentFDS::m_iModulationSpeed	Instrument modulation rate
int	4		CInstrumentFDS::m_iModulationDepth	Instrument modulation depth
int	4		CInstrumentFDS::m_iModulationDelay	Instrument modulation delay
char	1	CInstrumentFDS::SEQUENCE_COUNT	CSequence::m_iItemCount	Sequence item count	0 to MAX_SEQUENCE_ITEMS
int	4	^	CSequence::m_iLoopPoint	Sequence loop point	-1 toSeqCount - 1
int	4	^	CSequence::m_iReleasePoint	Sequence release point	-1 toSeqCount - 1
int	4	^	CSequence::m_iSetting	Sequence setting type	seq_setting_t
char[]	Sequence item count	^	CSequence::m_cValues[Index]	Sequence data

Notes

• Information is based on CInstrumentFDS::LoadFile()
• FDS instruments stores its own sequences via CInstrumentFDS::StoreSequence(), separate from CSeqInstrument::Store()
  • These sequences only store 3 types, Volume, Arpeggio, and Pitch.
• In version 2.2, volume range was 0-15. Later versions have volume ranges from 0-31.
  • Loading FDS instrument versions 2.2 and older will have their volume doubled for compatibility.

N163 instruments

Data type	Unit size (bytes)	Repeat	Object/relevant variable in code	Description	Valid range	Notes	Present in instrument version
CSeqInstrument	size of CSeqInstrument			See Base instrument format.
int	4		m_iWaveSize	N163 wave size	4 to MAX_WAVE_SIZE	In FT 0.5.0 beta, m_iWaveSize is determined by m_iWaveCount / remaining_bytes
int	4		m_iWavePos	N163 wave position	0 to MAX_WAVE_SIZE - 1	Ignored if m_bAutoWavePos is enabled
int	4		m_bAutoWavePos	Automatic wave data RAM allocation	0, nonzero
int	4		m_iWaveCount	N163 wave count	1 to MAX_WAVE_COUNT
char[m_iWaveSize]	m_iWaveSize	m_iWaveCount	m_iSamples[MAX_WAVE_COUNT][MAX_WAVE_SIZE]	N163 wave sample	0 to 15

Notes

• Information is based on CInstrumentN163::Store() and instrument file binary analysis
• Automatic wave data RAM allocation feature is from FT 0.5.0 beta.
• Fifth sequence type is named Wave Index.

S5B instruments

• Same format as Base instrument format.
• Fifth sequence type is named Noise / Mode.

Notes

• Information is based on CSeqInstrument::Store()
• Similar to 2A03 instruments but with no special considerations for DPCM