A Software MIDI Synthesizer library with OPN2 (YM2612) emulator

Project README


libOPNMIDI is a free Software MIDI synthesizer library with OPN2 (YM2612) and OPNA (YM2608) emulation.

OPNMIDI Library: Copyright (c) 2017-2024 Vitaly Novichkov [email protected]

Library is based on core of the libADLMIDI, a MIDI playing library with OPL3 emulation.

  • Semaphore-CI: Build Status
  • AppVeyor CI: Build status
  • Travis CI: Build Status

Tested on platforms

  • Linux GCC 4.8, 4.9, 5.4 / CLang
  • Mac OS X CLang (Xcode 7.x)
  • Windows MinGW 4.9.x, 5.2
  • Android NDK 12b/13
  • OpenBSD
  • Haiku
  • Emscripten

Key features

  • OPN2 emulation
  • Rudimentary OPNA emulation
  • Customizable bank of FM patches (You have to use the bank editor to create own soundbank)
  • Stereo sound
  • Number of simulated OPN2/OPNA chips can be specified as 1-100 (maximum 600 channels!)
  • Pan (binary panning, i.e. left/right side on/off)
  • Pitch-bender with adjustable range
  • Vibrato that responds to RPN/NRPN parameters
  • Sustain (a.k.a. Pedal hold) and Sostenuto enable/disable
  • MIDI and RMI file support
  • Real-Time MIDI API support
  • MIDI and RMI file support
  • loopStart / loopEnd tag support (Final Fantasy VII)
  • 111'th controller based loop start (RPG-Maker)
  • Use automatic arpeggio with chords to relieve channel pressure
  • Support for multiple concurrent MIDI synthesizers (per-track device/port select FF 09 message), can be used to overcome 16 channel limit
  • Partial support for GS and XG standards (having more instruments than in one 128:128 GM set and ability to use multiple channels for percussion purposes, and support for some GS/XG exclusive controllers)
  • CC74 "Brightness" affects a modulator scale (to simulate frequency cut-off on WT synths)
  • Portamento support (CC5, CC37, and CC65)
  • SysEx support that supports some generic, GS, and XG features
  • Full-panning stereo option (works for emulators only)

How to build

To build libOPNMIDI you need to use CMake:

mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
sudo make install


The library is licensed under in it's parts LGPL 2.1+, GPL v2+, GPL v3+, and MIT.

  • Nuked OPN2 emulator is licensed under LGPL v2.1+.
  • GENS 2.10 emulator is licensed under LGPL v2.1+.
  • MAME YM2612 emulator is licensed under GPL v2+.
  • Genesis Plus GX emulator is licensed under GPL v2+.
  • Neko Project II Kai (fmgen, developed by "cisc" [email protected]) OPNA emulator is licensed under MIT-compatible license.
  • PMDWin emulator OPNA emulator is licensed under BSD 2-Clause.
  • MAME YM2608 emulator is licensed under GPL v2+.
  • Chip interfaces are licensed under LGPL v2.1+.
  • File Reader class and MIDI Sequencer is licensed under MIT.
  • Other parts of library are licensed under GPLv3+.

Available CMake options

  • CMAKE_INSTALL_PREFIX - destination folder where libOPNMIDI will be installed. On Linux it is /usr/local/ by default.

  • CMAKE_BUILD_TYPE - Build types: Debug or Release. Also MinSizeRel or RelWithDebInfo.

  • WITH_MIDIPLAY - (ON/OFF, default OFF) Build demo MIDI player (Requires SDL2 and also pthread on Windows with MinGW)

  • WITH_VLC_PLUGIN - (ON/OFF, default OFF) Compile VLC plugin. For now, works on Linux and VLC. Support for other platforms comming soon!

  • WITH_WINMMDRV - (ON/OFF, default OFF) (Windows platform only) Compile the WinMM MIDI driver to use libOPNMIDI as a system MIDI device.

    • WITH_WINMMDRV_PTHREADS - (ON/OFF, default ON) Link libwinpthreads statically (when using pthread-based builds).
    • WITH_WINMMDRV_MINGWEX - (ON/OFF, default OFF) Link libmingwex statically (when using vanilla MinGW builds). Useful for targetting to pre-XP Windows versions.
  • WITH_MIDI2VGM - (ON/OFF, default OFF) Build MIDI to VGM converter tool.

  • WITH_DAC_UTIL - (ON/OFF, default OFF) Build YM2612 CH6 DAC testing utility.

  • WITH_MIDI_SEQUENCER - (ON/OFF, default ON) Enable built-in MIDI sequencer to play loaded MIDI files. When you will disable MIDI sequencer, Real-Time functions only will work. Use this option when you are making MIDI plugin or real-time MIDI driver.

  • USE_MAME_EMULATOR - (ON/OFF, default ON) Enable support for MAME YM2612 emulator. Well-accurate and fast on slow devices.

  • USE_NUKED_EMULATOR - (ON/OFF, default ON) Enable support for Nuked OPN2 emulator. Very accurate, however, requires a very powerful CPU. Is not recommended for mobile devices!.

  • USE_GENS_EMULATOR - (ON/OFF, default ON) Enable support for GENS 2.10 emulator. Very outdated and inaccurate, but fastest.

  • USE_GX_EMULATOR - (ON/OFF, default OFF) Enable support for Genesis Plus GX emulator. (experimental!)

  • USE_NP2_EMULATOR - (ON/OFF, default ON) Enable support for Neko Project 2 YM2608 emulator. Semi-accurate, but fast on slow devices.

  • USE_MAME_2608_EMULATOR - (ON/OFF, default ON) Enable support for MAME YM2608 emulator. Well-accurate and fast on slow devices.

  • WITH_HQ_RESAMPLER - (ON/OFF, default OFF) Build with support for high quality resampling (requires zita-resampler to be installed.

  • WITH_MUS_SUPPORT - (ON/OFF, default ON) Enable support for DMX MUS format in built-in MIDI sequencer.

  • WITH_XMI_SUPPORT - (ON/OFF, default ON) Enable support for AIL XMI format in built-in MIDI sequencer.

  • WITH_UNIT_TESTS - (ON/OFF, default OFF) Also compile unit-tests of internal features.

  • libOPNMIDI_STATIC - (ON/OFF, default ON) Build static library

  • libOPNMIDI_SHARED - (ON/OFF, default OFF) Build shared library

You also can build library manually:

You need to make in the any IDE a library project and put into it next files (or include those files into subfolder of your exist project instead if you want to use it statically):

Useful macros

  • BWMIDI_DISABLE_XMI_SUPPORT - Disables XMI to MIDI converter
  • BWMIDI_DISABLE_MUS_SUPPORT - Disables MUS to MIDI converter
  • OPNMIDI_DISABLE_MIDI_SEQUENCER - Completely disables built-in MIDI sequencer.
  • OPNMIDI_USE_LEGACY_EMULATOR - Enables Gens 2.10 YM2612 emulator to be used. Nuked OPN2 is used by default if macro is not defined.

Public header (include)

  • opnmidi.h - Library API, use it to control library

Internal code (src)

  • opnbank.h - bank structures definition

  • opnmidi_private.hpp - header of internal private APIs

  • opnmidi.cpp - code of library

  • opnmidi_load.cpp - Source of file loading and parsing processing

  • opnmidi_midiplay.cpp - MIDI event sequencer

  • opnmidi_opn2.cpp - OPN2 chips manager

  • opnmidi_private.cpp - some internal functions sources

  • opnmidi_bankmap.h - MIDI bank hash table

  • opnmidi_bankmap.tcc - MIDI bank hash table (Implementation)

  • opnmidi_cvt.hpp - Instrument conversion template

  • opnmidi_ptr.hpp - Custom implementations of smart pointers for C++98

  • file_reader.hpp - Generic file and memory reader

  • chips/opn_chip_base.h - Header of base class over all emulation cores

  • chips/opn_chip_base.tcc - Code of base class over all emulation cores

  • chips/gens_opn2.h - Header of emulator frontent over Gens 2.10 emulator

  • chips/gens_opn2.cpp - Code of emulator frontent over Gens 2.10 emulator

  • chips/gens/Ym2612_ChipEmu.h - Gens 2.10 OPN2 Emulation header

  • chips/gens/Ym2612_ChipEmu.cpp - Code of Gens 2.10 OPN2 emulator by Stéphane Dallongeville, improved by Shay Green

  • chips/mame_opn2.h - Header of emulator frontent over MAME YM2612 emulator

  • chips/mame_opn2.cpp - Code of emulator frontent over MAME YM2612 emulator

  • chips/mame/mame_ym2612fm.h - MAME YM2612 Emulation header

  • chips/mame/mame_ym2612fm.cpp - Code of MAME YM2612 emulator by Jarek Burczyński and Tatsuyuki Satoh, improved by Eke-Eke

  • chips/nuked_opn2.h - Header of emulator frontent over Nuked OPN2 emulator

  • chips/nuked_opn2.cpp - Code of emulator frontent over Nuked OPN2 emulator

  • chips/nuked/ym3438.h - Nuked OPN2 Emulation header

  • chips/nuked/ym3438.cpp - Code of Nuked OPN2 emulator by Alexey Khokholov

  • chips/np2/* - Code of Neko Project 2 YM2608 emulator by cisc.

  • chips/mamefm/* - Code of MAME YM2608 emulator by Jarek Burczynski and Tatsuyuki Satoh.

  • wopn/* - WOPN bank format library

MIDI Sequencer

To remove MIDI Sequencer, define OPNMIDI_DISABLE_MIDI_SEQUENCER macro and remove all those files

  • adlmidi_sequencer.cpp - MIDI Sequencer related source
  • cvt_mus2mid.hpp - MUS2MID converter source (define BWMIDI_DISABLE_MUS_SUPPORT macro to remove MUS support)
  • cvt_xmi2mid.hpp - XMI2MID converter source (define BWMIDI_DISABLE_XMI_SUPPORT macro to remove XMI support)
  • fraction.hpp - Fraction number handling (Used by Sequencer only)
  • midi_sequencer.h - MIDI Sequencer C bindings
  • midi_sequencer.hpp - MIDI Sequencer C++ declaration
  • midi_sequencer_impl.hpp - MIDI Sequencer C++ implementation (must be once included into one of CPP together with interfaces initializations)

Important: Please use GENS emulator only on mobile or any non-power devices because it requires very small CPU power. Nuked OPN2 emulator is very accurate (compared to real OPN2 chip), however, it requires a VERY POWERFUL device even for a single chip emulation and is a high probability that your device will lag and playback will be dirty and choppy. Use of MAME OPN2 is recommended in such cases.

Working demos

  • Moondust MusPlay for Win32 and Win64 (also available for other platforms as part of Moondust Project) - a little music player which uses SDL Mixer X library (fork of the SDL Mixer 2.0) which has embedded libOPNMIDI to play MIDI files independently from operating system's settings and drivers.
    (source code of player can be find here and source code of SDL Mixer X here)
  • OPNMIDI Player for Android - a little MIDI-player for Android which uses libOPNMIDI to play MIDI files and provides flexible GUI with ability to change bank, flags, number of emulated chips, etc.



  • Fixed the work on big endian processors
  • Fixed ARM64 build on some platforms
  • Improved support of the EA-MUS files (Thanks to dashodanger)
  • Fixed crash on attempt to change the volume of a blank note
  • Removed PMDwin and Genesis Plus GX emulatirs because of their very low quality
  • Added new YMFM emulators for the OPN2 and for the OPNA (will be available for C++14 compilers only. If your compiler doesn't supports C++14, you can disable these emulators by defining the -DOPNMIDI_DISABLE_YMFM_EMULATOR macro if you build the code of libOPNMIDI at your own build tree)
  • OPNMIDI player tool now has the ganining factor to change the output volume
  • OPNMIDI player tool now is able to output WAV files of different sample formats

1.5.1 2022-10-31

  • Added an ability to disable the automatical arpeggio
  • Updated the GENS chip emulator from the 2.10 into GS/II (thanks to @freq-mod for the help)
  • Added an ability to set number of loops
  • Added an ability to disable/enable playing of selected MIDI channels
  • Fixed memory damages and crashes while playing XMI files
  • Added the chip channels allocation mode option
  • Fixed the playback of multi-song XMI files
  • Added an ability to switch the XMI song on the fly 2020-10-11

  • Fixed an incorrect timer processing when using a real-time interface

1.5.0 2020-09-28

  • Drum note length expanding is now supported in real-time mode (Thanks to Jean Pierre Cimalando for a work!)
  • Added support for OPNA chip with Neko Project II Kai YM2602 emulator usage (Thanks to Jean Pierre Cimalando for a work!)
  • Added VGM file dumper which allows to output OPN2 commands into VGM file. (A new MIDI to VGM tool is now created with basing on libOPNMIDI)
  • Fixed an incorrect work of CC-121 (See for details)
  • Internality has been refactored and improved

1.4.0 2018-10-01

  • Implemented a full support for Portamento! (Thanks to Jean Pierre Cimalando for a work!)
  • Added support for SysEx event handling! (Thanks to Jean Pierre Cimalando for a work!)
  • Added support for GS way of custom drum channels (through SysEx events)
  • Ignore some NRPN events and lsb bank number when using GS standard (after catching of GS Reset SysEx call)
  • Added support for CC66-Sostenuto controller (Pedal hold of currently-pressed notes only while CC64 holds also all next notes)
  • Added support for CC67-SoftPedal controller (SoftPedal lowers the volume of notes played)
  • Resolved a trouble which sometimes makes a junk noise sound and unnecessary overuse of chip channels
  • Volume models support taken from libADLMIDI has been adapted to OPN2's chip speficis
  • Fixed inability to play high notes due physical tone frequency out of range on the OPN2 chip
  • Added support for full-panning stereo option

1.3.0 2018-06-19

  • Optimizing the MIDI banks management system for MultiBanks (Thanks to Jean Pierre Cimalando for a work!)
  • Fixed incorrect initial MIDI tempo when MIDI file doesn't includes the tempo event
  • Fixed an incorrect processing of auto-flags
  • MAME YM2612 now results a more accurate sound as internal using of native sample rate makes more correct sound generation
  • Channel and Note Aftertouch features are now supported correctly! Aftertouch is the tremolo / vibrato, NOT A VOLUME!
  • Added optional HQ resampler for Nuked OPL3 emulators which does usage of Zita-Resampler library (Thanks to Jean Pierre Cimalando for a work!)

1.2.0 2018-04-24

  • Added ability to disable MUS and XMI converters
  • Added ability to disable embedded MIDI sequencer to use library as RealTime synthesizer only or use any custom MIDI sequencer plugins.
  • Fixed blank instruments fallback in multi-bank support. When using non-zero bank, if instrument is blank, then, instrument will be taken from a root (I.e. zero bank).
  • Added support for real-time switching the emulator
  • Added support for MAME YM2612 Emulator
  • Added support for CC-120 - "All sound off" on the MIDI channel
  • Changed logic of CC-74 Brightness to affect sound only between 0 and 64 like real XG synthesizers. Ability to turn on a full-ranged brightness (to use full 0...127 range) is kept.
  • Added support for different output sample formats (PCM8, PCM8U, PCM16, PCM16U, PCM32, PCM32U, Float32, and Float64) (Thanks to Jean Pierre Cimalando for a work!)
  • Reworked MIDI channels management to avoid any memory reallocations while music processing for a hard real time. (Thanks to Jean Pierre Cimalando for a work!)

1.1.0 2018-01-21

  • First stable release
  • Contains all features are made in libADLMIDI 1.3.1

1.0.0-beta 2017-05-06

  • First experimental release
Open Source Agenda is not affiliated with "LibOPNMIDI" Project. README Source: Wohlstand/libOPNMIDI
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