Preset data

Prerequisite

This section requires a basic understanding of SoundFont 2.04 and binary.

SoundFont preset data is accessible through SoundFont3.presetData. There are 9 mandatory chunks, named the "HYDRA structure" in the spec.

Preset data contains references that form a graph structure:

• Multiple preset zones can reference one instrument.
• Likewise, multiple instrument zones can reference one sample.

Preprocessed data

Preset data that are parsed into an array can be accessed accordingly:

• Banks - SoundFont3.banks
• Presets - SoundFont3.presets
• Instruments - SoundFont3.instruments
• Samples - SoundFont3.samples

phdr - Preset headers

Accessible through SoundFont3.presetData.presetHeaders

This chunk contains preset info with one record per preset. library, genre and morphology are reserved for future library management - not currently used.

// Multiple records
char[20] presetName = "presetName" // 20 byte
uint16_t presetNumber = 3 // 2 byte
uint16_t bankNumber = 127 // 2 byte - 127 or 128
uint16_t presetZoneId = 3 // 4 byte
uint16_t library = 0 // 4 byte
uint16_t genre = 0 // 4 byte
uint16_t morphology = 0 // 4 byte
// Multiple 38 byte total

A terminal record is required to signify end of phdr chunk. All values are zero except:

char[20] presetName = "EOP" // Indicate end of chunck
uint16_t presetZoneId = 3 // Number of preset zones

pbag - Preset zone indices

Accessible through SoundFont3.presetData.presetZones

List preset zones. The generator is the output of the modulator.

// Multiple records
uint16_t generatorId = 3 // 2 byte
uint16_t modulatorId = 1 // 2 byte
// Multiple 4 byte total

pmod - Preset modulators

Accessible through SoundFont3.presetData.presetModulators

Defines a preset modulator, which is represented by the following calculation and diagram:

float p = cmath::abs(primarySource);
float s = cmath::abs(modulatorDestination);
float modulatorDestination +=
  modulatorTransform(modulatorGain * p * s);

MIDI commands can be used as input for modulators. Only official MIDI commands can be used with SoundFont. Popular commands include:

• MIDI CC64 - Sustain pedal
• MIDI CC66 - Soft pedal
• MIDI CC67 - Sostenuto pedal

// Multiple records
uint16_t modulatorSourceId = 3 // 2 byte
uint16_t modulatorDestinationId = 1 // 2 byte
int16_t modulatorGain = 1 // 2 byte
uint16_t modulatorGainSourceId = 1 // 2 byte
uint16_t modulatorTransformId = 1 // 2 byte
// Multiple 10 byte total

pgen - Preset generators

Accessible through SoundFont3.presetData.presetGenerators

Defines a preset generator which is a modulator node. This node can be referenced to create a graph of modulators:

Generators may specify a range of MIDI keys or velocities. Some generators only specify a signed 16-bit value.

// Multiple records
uint16_t modulatorId = 1 // 2 byte

// Then any of the combination below:
uint8_t minValue  = 0 // 1 byte
uint8_t maxValue  = 60 // 1 byte

uint16_t amount1 // 2 byte

int16_t  amount2// 2 byte
// Multiple 4 byte

---

 

inst - Instrument headers

Accessible through SoundFont3.presetData.instrumentHeaders

This chunk contains instrument info with one record per instrument.

// Multiple records
char[20] instrumentName = "instrumentName" // 20 byte
uint16_t[] instrumentZoneId = 3 // 2 byte
// Multiple 22 byte

A terminal record is required to signify end of inst chunk. All values are zero except:

char[20] instrumentName = "EOP" // Indicate end of chunck
uint16_t[] instrumentZoneId = 3 // Number of instrument zones

ibag - Instrument zone indices

Accessible through SoundFont3.presetData.instrumentZones

List instrument zones. The generator is the output of the modulator.

// Multiple records
uint16_t generatorId = 3 // 2 byte
uint16_t modulatorId = 1 // 2 byte
// Multiple 4 byte total

imod - Instrument modulators

Accessible through SoundFont3.presetData.instrumentModulators

Defines an instrument modulator. See pmod for structure.

igen - Instrument generators

Accessible through SoundFont3.presetData.instrumentGenerators

Defines an instrument generator. See pgen for structure.

---

 

shdr - Sample Headers

Accessible through SoundFont3.presetData.sampleHeaders

This chunk contains sample info with one record per sample.

// Multiple records
char[20] sampleName = "sampleName" // 20 byte
uint32_t startByte = 0 // 4 byte
uint32_t endByte = 60 // 4 byte
uint32_t startLoopByte = 50 // 4 byte
uint32_t endLoopByte = 60 // 4 byte
uint32_t sampleRate = 44100 // 4 byte
uint8_t originalPitch = 60 // 1 byte
int8_t pitchCorrection = -4 // 1 byte
uint16_t romSampleLink = 0 // 2 byte
uint16_t romSampleType = 0 // 2 byte
// Multiple 46 byte

A terminal record is required to signify end of shdr chunk. All values are zero except:

char[20] instrumentName = "EOS" // Indicate end of chunck
uint16_t[] instrumentZoneId = 88 // Number of samples