GENMIDI.OP2 OPL2 sound bank: Go parsing library

GENMIDI.OP2 is a sound bank file used by players based on DMX sound library to play MIDI files with General MIDI instruments using OPL2 sound chip (which was commonly installed on popular AdLib and Sound Blaster sound cards).

Major users of DMX sound library include:

  • Original Doom game engine (and games based on it: Heretic, Hexen, Strife, Chex Quest)
  • Raptor: Call of the Shadows

File extension

op2

KS implementation details

License: CC0-1.0
Minimal Kaitai Struct required: 0.9

References

This page hosts a formal specification of GENMIDI.OP2 OPL2 sound bank using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Go source code to parse GENMIDI.OP2 OPL2 sound bank

genmidi_op2.go

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

import (
	"github.com/kaitai-io/kaitai_struct_go_runtime/kaitai"
	"bytes"
)


/**
 * GENMIDI.OP2 is a sound bank file used by players based on DMX sound
 * library to play MIDI files with General MIDI instruments using OPL2
 * sound chip (which was commonly installed on popular AdLib and Sound
 * Blaster sound cards).
 * 
 * Major users of DMX sound library include:
 * 
 * * Original Doom game engine (and games based on it: Heretic, Hexen, Strife, Chex Quest)
 * * Raptor: Call of the Shadows
 * @see <a href="http://www.fit.vutbr.cz/~arnost/muslib/op2_form.zip">Source</a>
 * @see <a href="http://doom.wikia.com/wiki/GENMIDI">Source</a>
 * @see <a href="http://www.shikadi.net/moddingwiki/OP2_Bank_Format">Source</a>
 */
type GenmidiOp2 struct {
	Magic []byte
	Instruments []*GenmidiOp2_InstrumentEntry
	InstrumentNames []string
	_io *kaitai.Stream
	_root *GenmidiOp2
	_parent interface{}
}
func NewGenmidiOp2() *GenmidiOp2 {
	return &GenmidiOp2{
	}
}

func (this *GenmidiOp2) Read(io *kaitai.Stream, parent interface{}, root *GenmidiOp2) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp1, err := this._io.ReadBytes(int(8))
	if err != nil {
		return err
	}
	tmp1 = tmp1
	this.Magic = tmp1
	if !(bytes.Equal(this.Magic, []uint8{35, 79, 80, 76, 95, 73, 73, 35})) {
		return kaitai.NewValidationNotEqualError([]uint8{35, 79, 80, 76, 95, 73, 73, 35}, this.Magic, this._io, "/seq/0")
	}
	this.Instruments = make([]*GenmidiOp2_InstrumentEntry, 175)
	for i := range this.Instruments {
		tmp2 := NewGenmidiOp2_InstrumentEntry()
		err = tmp2.Read(this._io, this, this._root)
		if err != nil {
			return err
		}
		this.Instruments[i] = tmp2
	}
	this.InstrumentNames = make([]string, 175)
	for i := range this.InstrumentNames {
		tmp3, err := this._io.ReadBytes(int(32))
		if err != nil {
			return err
		}
		tmp3 = kaitai.BytesTerminate(kaitai.BytesStripRight(tmp3, 0), 0, false)
		this.InstrumentNames[i] = string(tmp3)
	}
	return err
}
type GenmidiOp2_InstrumentEntry struct {
	Flags uint16
	Finetune uint8
	Note uint8
	Instruments []*GenmidiOp2_Instrument
	_io *kaitai.Stream
	_root *GenmidiOp2
	_parent *GenmidiOp2
}
func NewGenmidiOp2_InstrumentEntry() *GenmidiOp2_InstrumentEntry {
	return &GenmidiOp2_InstrumentEntry{
	}
}

func (this *GenmidiOp2_InstrumentEntry) Read(io *kaitai.Stream, parent *GenmidiOp2, root *GenmidiOp2) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp4, err := this._io.ReadU2le()
	if err != nil {
		return err
	}
	this.Flags = uint16(tmp4)
	tmp5, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.Finetune = tmp5
	tmp6, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.Note = tmp6
	this.Instruments = make([]*GenmidiOp2_Instrument, 2)
	for i := range this.Instruments {
		tmp7 := NewGenmidiOp2_Instrument()
		err = tmp7.Read(this._io, this, this._root)
		if err != nil {
			return err
		}
		this.Instruments[i] = tmp7
	}
	return err
}

/**
 * MIDI note for fixed instruments, 0 otherwise
 */
type GenmidiOp2_Instrument struct {
	Op1 *GenmidiOp2_OpSettings
	Feedback uint8
	Op2 *GenmidiOp2_OpSettings
	Unused uint8
	BaseNote int16
	_io *kaitai.Stream
	_root *GenmidiOp2
	_parent *GenmidiOp2_InstrumentEntry
}
func NewGenmidiOp2_Instrument() *GenmidiOp2_Instrument {
	return &GenmidiOp2_Instrument{
	}
}

func (this *GenmidiOp2_Instrument) Read(io *kaitai.Stream, parent *GenmidiOp2_InstrumentEntry, root *GenmidiOp2) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp8 := NewGenmidiOp2_OpSettings()
	err = tmp8.Read(this._io, this, this._root)
	if err != nil {
		return err
	}
	this.Op1 = tmp8
	tmp9, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.Feedback = tmp9
	tmp10 := NewGenmidiOp2_OpSettings()
	err = tmp10.Read(this._io, this, this._root)
	if err != nil {
		return err
	}
	this.Op2 = tmp10
	tmp11, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.Unused = tmp11
	tmp12, err := this._io.ReadS2le()
	if err != nil {
		return err
	}
	this.BaseNote = int16(tmp12)
	return err
}

/**
 * Feedback/AM-FM (both operators)
 */

/**
 * Base note offset
 */

/**
 * OPL2 settings for one operator (carrier or modulator)
 */
type GenmidiOp2_OpSettings struct {
	TremVibr uint8
	AttDec uint8
	SustRel uint8
	Wave uint8
	Scale uint8
	Level uint8
	_io *kaitai.Stream
	_root *GenmidiOp2
	_parent *GenmidiOp2_Instrument
}
func NewGenmidiOp2_OpSettings() *GenmidiOp2_OpSettings {
	return &GenmidiOp2_OpSettings{
	}
}

func (this *GenmidiOp2_OpSettings) Read(io *kaitai.Stream, parent *GenmidiOp2_Instrument, root *GenmidiOp2) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp13, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.TremVibr = tmp13
	tmp14, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.AttDec = tmp14
	tmp15, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.SustRel = tmp15
	tmp16, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.Wave = tmp16
	tmp17, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.Scale = tmp17
	tmp18, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.Level = tmp18
	return err
}

/**
 * Tremolo/vibrato/sustain/KSR/multi
 */

/**
 * Attack rate/decay rate
 */

/**
 * Sustain level/release rate
 */

/**
 * Waveform select
 */

/**
 * Key scale level
 */

/**
 * Output level
 */