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:
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.
All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.
The Python runtime library can be installed from PyPI:
python3 -m pip install kaitaistructParse a local file and get structure in memory:
data = GenmidiOp2.from_file("path/to/local/file.op2")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = GenmidiOp2(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.magic # => get magic
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 9):
raise Exception("Incompatible Kaitai Struct Python API: 0.9 or later is required, but you have %s" % (kaitaistruct.__version__))
class GenmidiOp2(KaitaiStruct):
"""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
.. seealso::
Source - http://www.fit.vutbr.cz/~arnost/muslib/op2_form.zip
.. seealso::
Source - https://doom.fandom.com/wiki/GENMIDI
.. seealso::
Source - https://moddingwiki.shikadi.net/wiki/OP2_Bank_Format
"""
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.magic = self._io.read_bytes(8)
if not self.magic == b"\x23\x4F\x50\x4C\x5F\x49\x49\x23":
raise kaitaistruct.ValidationNotEqualError(b"\x23\x4F\x50\x4C\x5F\x49\x49\x23", self.magic, self._io, u"/seq/0")
self.instruments = []
for i in range(175):
self.instruments.append(GenmidiOp2.InstrumentEntry(self._io, self, self._root))
self.instrument_names = []
for i in range(175):
self.instrument_names.append((KaitaiStream.bytes_terminate(KaitaiStream.bytes_strip_right(self._io.read_bytes(32), 0), 0, False)).decode(u"ASCII"))
class InstrumentEntry(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.flags = self._io.read_u2le()
self.finetune = self._io.read_u1()
self.note = self._io.read_u1()
self.instruments = []
for i in range(2):
self.instruments.append(GenmidiOp2.Instrument(self._io, self, self._root))
class Instrument(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.op1 = GenmidiOp2.OpSettings(self._io, self, self._root)
self.feedback = self._io.read_u1()
self.op2 = GenmidiOp2.OpSettings(self._io, self, self._root)
self.unused = self._io.read_u1()
self.base_note = self._io.read_s2le()
class OpSettings(KaitaiStruct):
"""OPL2 settings for one operator (carrier or modulator)
"""
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.trem_vibr = self._io.read_u1()
self.att_dec = self._io.read_u1()
self.sust_rel = self._io.read_u1()
self.wave = self._io.read_u1()
self.scale = self._io.read_u1()
self.level = self._io.read_u1()