midiutil/src/midiutil/MidiFile.py

1077 lines
36 KiB
Python

# -----------------------------------------------------------------------------
# Name: MidiFile.py
# Purpose: MIDI file manipulation utilities
#
# Author: Mark Conway Wirt <emergentmusics) at (gmail . com>
#
# Created: 2008/04/17
# Copyright: (c) 2009 Mark Conway Wirt
# License: Please see License.txt for the terms under which this
# software is distributed.
# -----------------------------------------------------------------------------
import struct
import sys
import math
# TICKSPERBEAT is the number of "ticks" (time measurement in the MIDI
# file) that corresponds to one beat. This number is somewhat
# arbitrary, but should be chosen to provide adequate temporal
# resolution.
TICKSPERBEAT = 128
controllerEventTypes = {
'pan': 0x0a
}
class MIDIEvent:
'''
The class to contain the MIDI Event (placed on MIDIEventList.
'''
def __init__(self):
self.type = 'unknown'
self.time = 0
self.ord = 0
def __cmp__(self, other):
''' Sorting function for events.'''
if self.time < other.time:
return -1
elif self.time > other.time:
return 1
else:
if self.ord < other.ord:
return -1
elif self.ord > other.ord:
return 1
else:
return 0
class GenericEvent():
'''
The event class from which specific events are derived
'''
def __init__(self, time):
self.time = time
self.type = 'Unknown'
def __eq__(self, other):
'''
Equality operator for Generic Events and derived classes.
In the processing of the event list, we have need to remove
duplicates. To do this we rely on the fact that the classes
are hashable, and must therefore have an equality operator
(__hash__() and __eq__() must both be defined).
This is the most embarrassing portion of the code, and anyone
who knows about OO programming would find this almost
unbelievable. Here we have a base class that knows specifics
about derived classes, thus breaking the very spirit of OO
programming.
I suppose I should go back and restructure the code, perhaps
removing the derived classes altogether. At some point perhaps
I will.
'''
if self.time != other.time or self.type != other.type:
return False
# What follows is code that encodes the concept of equality
# for each derived class. Believe it f you dare.
if self.type == 'note':
if self.pitch != other.pitch or self.channel != other.channel:
return False
if self.type == 'tempo':
if self.tempo != other.tempo:
return False
if self.type == 'programChange':
if self.programNumber != other.programNumber or \
self.channel != other.channel:
return False
if self.type == 'trackName':
if self.trackName != other.trackName:
return False
if self.type == 'controllerEvent':
if self.parameter1 != other.parameter1 or \
self.parameter2 != other.parameter2 or \
self.channel != other.channel or \
self.eventType != other.eventType:
return False
if self.type == 'SysEx':
if self.manID != other.manID:
return False
if self.type == 'UniversalSysEx':
if self.code != other.code or \
self.subcode != other.subcode or \
self.sysExChannel != other.sysExChannel:
return False
return True
def __hash__(self):
'''
Return a hash code for the object.
This is needed for the removal of duplicate objects from the
event list. The only real requirement for the algorithm is
that the hash of equal objects must be equal. There is
probably great opportunity for improvements in the hashing
function.
'''
# Robert Jenkin's 32 bit hash.
a = int(self.time)
a = (a + 0x7ed55d16) + (a << 12)
a = (a ^ 0xc761c23c) ^ (a >> 19)
a = (a + 0x165667b1) + (a << 5)
a = (a + 0xd3a2646c) ^ (a << 9)
a = (a + 0xfd7046c5) + (a << 3)
a = (a ^ 0xb55a4f09) ^ (a >> 16)
return a
class MIDITrack:
'''A class that encapsulates a MIDI track
'''
# Nested class definitions.
class note(GenericEvent):
'''A class that encapsulates a note
'''
def __init__(self, channel, pitch, time, duration, volume):
GenericEvent.__init__(self, time)
self.pitch = pitch
self.duration = duration
self.volume = volume
self.type = 'note'
self.channel = channel
def compare(self, other):
'''Compare two notes for equality.
'''
if self.pitch == other.pitch and \
self.time == other.time and \
self.duration == other.duration and \
self.volume == other.volume and \
self.type == other.type and \
self.channel == other.channel:
return True
else:
return False
class tempo(GenericEvent):
'''A class that encapsulates a tempo meta-event
'''
def __init__(self, time, tempo):
GenericEvent.__init__(self, time)
self.type = 'tempo'
self.tempo = int(60000000 / tempo)
class programChange(GenericEvent):
'''A class that encapsulates a program change event.
'''
def __init__(self, channel, time, programNumber):
GenericEvent.__init__(self, time,)
self.type = 'programChange'
self.programNumber = programNumber
self.channel = channel
class SysExEvent(GenericEvent):
'''A class that encapsulates a System Exclusive event.
'''
def __init__(self, time, manID, payload):
GenericEvent.__init__(self, time,)
self.type = 'SysEx'
self.manID = manID
self.payload = payload
class UniversalSysExEvent(GenericEvent):
'''A class that encapsulates a Universal System Exclusive event.
'''
def __init__(self,
time, realTime, sysExChannel,
code, subcode, payload):
GenericEvent.__init__(self, time,)
self.type = 'UniversalSysEx'
self.realTime = realTime
self.sysExChannel = sysExChannel
self.code = code
self.subcode = subcode
self.payload = payload
class ControllerEvent(GenericEvent):
'''A class that encapsulates a program change event.
'''
def __init__(self, channel, time, eventType, parameter1):
GenericEvent.__init__(self, time,)
self.type = 'controllerEvent'
self.parameter1 = parameter1
self.channel = channel
self.eventType = eventType
class trackName(GenericEvent):
'''A class that encapsulates a program change event.
'''
def __init__(self, time, trackName):
GenericEvent.__init__(self, time,)
self.type = 'trackName'
self.trackName = trackName
def __init__(self, removeDuplicates, deinterleave):
'''Initialize the MIDITrack object.
'''
self.headerString = struct.pack('cccc', 'M', 'T', 'r', 'k')
self.dataLength = 0 # Is calculated after the data is in place
self.MIDIdata = ""
self.closed = False
self.eventList = []
self.MIDIEventList = []
self.remdep = removeDuplicates
self.deinterleave = deinterleave
def addNoteByNumber(self, channel, pitch, time, duration, volume):
'''
Add a note by chromatic MIDI number
'''
self.eventList.append(MIDITrack.note(channel, pitch,
time, duration, volume))
def addControllerEvent(self, channel, time, eventType, paramerter1):
'''
Add a controller event.
'''
self.eventList.append(
MIDITrack.ControllerEvent(channel, time, eventType, paramerter1))
def addTempo(self, time, tempo):
'''
Add a tempo change (or set) event.
'''
self.eventList.append(MIDITrack.tempo(time, tempo))
def addSysEx(self, time, manID, payload):
'''
Add a SysEx event.
'''
self.eventList.append(MIDITrack.SysExEvent(time, manID, payload))
def addUniversalSysEx(self, time, code, subcode,
payload, sysExChannel=0x7F, realTime=False):
'''
Add a Universal SysEx event.
'''
self.eventList.append(
MIDITrack.UniversalSysExEvent(time, realTime, sysExChannel,
code, subcode, payload))
def addProgramChange(self, channel, time, program):
'''
Add a program change event.
'''
self.eventList.append(MIDITrack.programChange(channel, time, program))
def addTrackName(self, time, trackName):
'''
Add a track name event.
'''
self.eventList.append(MIDITrack.trackName(time, trackName))
def changeNoteTuning(self, tunings, sysExChannel=0x7F,
realTime=False, tuningProgam=0):
'''Change the tuning of MIDI notes
'''
payload = struct.pack('>B', tuningProgam)
payload = payload + struct.pack('>B', len(tunings))
for (noteNumber, frequency) in tunings:
payload = payload + struct.pack('>B', noteNumber)
MIDIFreqency = frequencyTransform(frequency)
for byte in MIDIFreqency:
payload = payload + struct.pack('>B', byte)
self.eventList.append(
MIDITrack.UniversalSysExEvent(0, realTime, sysExChannel,
8, 2, payload))
def processEventList(self):
'''
Process the event list, creating a MIDIEventList
For each item in the event list, one or more events in the MIDIEvent
list are created.
'''
# Loop over all items in the eventList
for thing in self.eventList:
if thing.type == 'note':
event = MIDIEvent()
event.type = "NoteOn"
event.time = thing.time * TICKSPERBEAT
event.pitch = thing.pitch
event.volume = thing.volume
event.channel = thing.channel
event.ord = 3
self.MIDIEventList.append(event)
event = MIDIEvent()
event.type = "NoteOff"
event.time = (thing.time + thing.duration) * TICKSPERBEAT
event.pitch = thing.pitch
event.volume = thing.volume
event.channel = thing.channel
event.ord = 2
self.MIDIEventList.append(event)
elif thing.type == 'tempo':
event = MIDIEvent()
event.type = "Tempo"
event.time = thing.time * TICKSPERBEAT
event.tempo = thing.tempo
event.ord = 3
self.MIDIEventList.append(event)
elif thing.type == 'programChange':
event = MIDIEvent()
event.type = "ProgramChange"
event.time = thing.time * TICKSPERBEAT
event.programNumber = thing.programNumber
event.channel = thing.channel
event.ord = 1
self.MIDIEventList.append(event)
elif thing.type == 'trackName':
event = MIDIEvent()
event.type = "TrackName"
event.time = thing.time * TICKSPERBEAT
event.trackName = thing.trackName
event.ord = 0
self.MIDIEventList.append(event)
elif thing.type == 'controllerEvent':
event = MIDIEvent()
event.type = "ControllerEvent"
event.time = thing.time * TICKSPERBEAT
event.eventType = thing.eventType
event.channel = thing.channel
event.paramerter1 = thing.parameter1
event.ord = 1
self.MIDIEventList.append(event)
elif thing.type == 'SysEx':
event = MIDIEvent()
event.type = "SysEx"
event.time = thing.time * TICKSPERBEAT
event.manID = thing.manID
event.payload = thing.payload
event.ord = 1
self.MIDIEventList.append(event)
elif thing.type == 'UniversalSysEx':
event = MIDIEvent()
event.type = "UniversalSysEx"
event.realTime = thing.realTime
event.sysExChannel = thing.sysExChannel
event.time = thing.time * TICKSPERBEAT
event.code = thing.code
event.subcode = thing.subcode
event.payload = thing.payload
event.ord = 1
self.MIDIEventList.append(event)
else:
print "Error in MIDITrack: Unknown event type"
sys.exit(2)
self.MIDIEventList.sort(lambda x, y: int(1000 * (x.time - y.time)))
if self.deinterleave:
self.deInterleaveNotes()
def removeDuplicates(self):
'''
Remove duplicates from the eventList.
This function will remove duplicates from the eventList. This
is necessary because we the MIDI event stream can become
confused otherwise.
'''
# For this algorithm to work, the events in the eventList must
# be hashable (that is, they must have a __hash__() and
# __eq__() function defined).
tempDict = {}
for item in self.eventList:
tempDict[item] = 1
self.eventList = tempDict.keys()
# Sort on type, them on time. Necessary because keys() has no
# requirement to return things in any order.
self.eventList.sort(lambda x, y: cmp(x.type, y.type))
# A bit of a hack.
self.eventList.sort(lambda x, y: int(1000 * (x.time - y.time)))
def closeTrack(self):
'''Called to close a track before writing
This function should be called to "close a track," that is to
prepare the actual data stream for writing. Duplicate events are
removed from the eventList, and the MIDIEventList is created.
Called by the parent MIDIFile object.
'''
if self.closed:
return
self.closed = True
if self.remdep:
self.removeDuplicates()
self.processEventList()
def writeMIDIStream(self):
'''
Write the meta data and note data to the packed MIDI stream.
'''
# Process the events in the eventList
self.writeEventsToStream()
# Write MIDI close event.
self.MIDIdata += struct.pack('BBBB', 0x00, 0xFF, 0x2F, 0x00)
# Calculate the entire length of the data and write to the header
self.dataLength = struct.pack('>L', len(self.MIDIdata))
def writeEventsToStream(self):
'''
Write the events in MIDIEvents to the MIDI stream.
'''
for event in self.MIDIEventList:
if event.type == "NoteOn":
code = 0x9 << 4 | event.channel
varTime = writeVarLength(event.time)
for timeByte in varTime:
self.MIDIdata += struct.pack('>B', timeByte)
self.MIDIdata += struct.pack('>B', code)
self.MIDIdata += struct.pack('>B', event.pitch)
self.MIDIdata += struct.pack('>B', event.volume)
elif event.type == "NoteOff":
code = 0x8 << 4 | event.channel
varTime = writeVarLength(event.time)
for timeByte in varTime:
self.MIDIdata += struct.pack('>B', timeByte)
self.MIDIdata += struct.pack('>B', code)
self.MIDIdata += struct.pack('>B', event.pitch)
self.MIDIdata += struct.pack('>B', event.volume)
elif event.type == "Tempo":
code = 0xFF
subcode = 0x51
fourbite = struct.pack('>L', event.tempo)
threebite = fourbite[1:4] # Just discard the MSB
varTime = writeVarLength(event.time)
for timeByte in varTime:
self.MIDIdata += struct.pack('>B', timeByte)
self.MIDIdata += struct.pack('>B', code)
self.MIDIdata += struct.pack('>B', subcode)
# Data length: 3
self.MIDIdata += struct.pack('>B', 0x03)
self.MIDIdata += threebite
elif event.type == 'ProgramChange':
code = 0xC << 4 | event.channel
varTime = writeVarLength(event.time)
for timeByte in varTime:
self.MIDIdata += struct.pack('>B', timeByte)
self.MIDIdata += struct.pack('>B', code)
self.MIDIdata += struct.pack('>B', event.programNumber)
elif event.type == 'TrackName':
varTime = writeVarLength(event.time)
for timeByte in varTime:
self.MIDIdata += struct.pack('>B', timeByte)
# Meta-event
self.MIDIdata += struct.pack('B', 0xFF)
# Event Type
self.MIDIdata += struct.pack('B', 0X03)
dataLength = len(event.trackName)
dataLenghtVar = writeVarLength(dataLength)
for i in range(0, len(dataLenghtVar)):
self.MIDIdata += struct.pack("b", dataLenghtVar[i])
self.MIDIdata += event.trackName
elif event.type == "ControllerEvent":
code = 0xB << 4 | event.channel
varTime = writeVarLength(event.time)
for timeByte in varTime:
self.MIDIdata += struct.pack('>B', timeByte)
self.MIDIdata += struct.pack('>B', code)
self.MIDIdata += struct.pack('>B', event.eventType)
self.MIDIdata += struct.pack('>B', event.paramerter1)
elif event.type == "SysEx":
code = 0xF0
varTime = writeVarLength(event.time)
for timeByte in varTime:
self.MIDIdata += struct.pack('>B', timeByte)
self.MIDIdata += struct.pack('>B', code)
payloadLength = writeVarLength(len(event.payload) + 2)
for lenByte in payloadLength:
self.MIDIdata += struct.pack('>B', lenByte)
self.MIDIdata += struct.pack('>B', event.manID)
self.MIDIdata += event.payload
self.MIDIdata += struct.pack('>B', 0xF7)
elif event.type == "UniversalSysEx":
code = 0xF0
varTime = writeVarLength(event.time)
for timeByte in varTime:
self.MIDIdata += struct.pack('>B', timeByte)
self.MIDIdata += struct.pack('>B', code)
# Do we need to add a length?
payloadLength = writeVarLength(len(event.payload) + 5)
for lenByte in payloadLength:
self.MIDIdata += struct.pack('>B', lenByte)
if event.realTime:
self.MIDIdata += struct.pack('>B', 0x7F)
else:
self.MIDIdata += struct.pack('>B', 0x7E)
self.MIDIdata += struct.pack('>B', event.sysExChannel)
self.MIDIdata += struct.pack('>B', event.code)
self.MIDIdata += struct.pack('>B', event.subcode)
self.MIDIdata += event.payload
self.MIDIdata += struct.pack('>B', 0xF7)
def deInterleaveNotes(self):
'''Correct Interleaved notes.
Because we are writing multiple notes in no particular order, we
can have notes which are interleaved with respect to their start
and stop times. This method will correct that. It expects that the
MIDIEventList has been time-ordered.
'''
tempEventList = []
stack = {}
for event in self.MIDIEventList:
if event.type == 'NoteOn':
if str(event.pitch) + str(event.channel) in stack:
stack[str(event.pitch) + str(event.channel)] \
.append(event.time)
else:
stack[str(event.pitch)+str(event.channel)] = [event.time]
tempEventList.append(event)
elif event.type == 'NoteOff':
if len(stack[str(event.pitch)+str(event.channel)]) > 1:
event.time = stack[str(event.pitch) + str(event.channel)] \
.pop()
tempEventList.append(event)
else:
stack[str(event.pitch)+str(event.channel)].pop()
tempEventList.append(event)
else:
tempEventList.append(event)
self.MIDIEventList = tempEventList
# A little trickery here. We want to make sure that NoteOff
# events appear before NoteOn events, so we'll do two sorts --
# on on type, one on time. This may have to be revisited, as
# it makes assumptions about how the internal sort works, and
# is in essence creating a sort on a primary and secondary
# key.
self.MIDIEventList.sort(lambda x, y: cmp(x.type, y.type))
self.MIDIEventList.sort(lambda x, y: int(1000 * (x.time - y.time)))
def adjustTime(self, origin):
'''
Adjust Times to be relative, and zero-origined
'''
if len(self.MIDIEventList) == 0:
return
tempEventList = []
runningTime = 0
for event in self.MIDIEventList:
adjustedTime = event.time - origin
event.time = adjustedTime - runningTime
runningTime = adjustedTime
tempEventList.append(event)
self.MIDIEventList = tempEventList
def writeTrack(self, fileHandle):
'''
Write track to disk.
'''
if not self.closed:
self.closeTrack()
fileHandle.write(self.headerString)
fileHandle.write(self.dataLength)
fileHandle.write(self.MIDIdata)
class MIDIHeader:
'''
Class to encapsulate the MIDI header structure.
This class encapsulates a MIDI header structure. It isn't used for much,
but it will create the appropriately packed identifier string that all
MIDI files should contain. It is used by the MIDIFile class to create a
complete and well formed MIDI pattern.
'''
def __init__(self, numTracks):
'''
Initialize the data structures
'''
self.headerString = struct.pack('cccc', 'M', 'T', 'h', 'd')
self.headerSize = struct.pack('>L', 6)
# Format 1 = multi-track file
self.format = struct.pack('>H', 1)
self.numTracks = struct.pack('>H', numTracks)
self.ticksPerBeat = struct.pack('>H', TICKSPERBEAT)
def writeFile(self, fileHandle):
fileHandle.write(self.headerString)
fileHandle.write(self.headerSize)
fileHandle.write(self.format)
fileHandle.write(self.numTracks)
fileHandle.write(self.ticksPerBeat)
class MIDIFile:
'''
Class that represents a full, well-formed MIDI pattern.
This is a container object that contains a header, one or more tracks,
and the data associated with a proper and well-formed MIDI pattern.
Calling:
MyMIDI = MidiFile(tracks, removeDuplicates=True, deinterleave=True)
normally
MyMIDI = MidiFile(tracks)
Arguments:
tracks: The number of tracks this object contains
removeDuplicates: If true (the default), the software will
remove duplicate events which have been added. For example,
two notes at the same channel, time, pitch, and duration would
be considered duplicate.
deinterleave: If True (the default), overlapping notes (same
pitch, same channel) will be modified so that they do not
overlap. Otherwise the sequencing software will need to figure
out how to interpret NoteOff events upon playback.
'''
def __init__(self, numTracks, removeDuplicates=True, deinterleave=True):
'''
Initialize the class
'''
self.header = MIDIHeader(numTracks)
self.tracks = list()
self.numTracks = numTracks
self.closed = False
for i in range(0, numTracks):
self.tracks.append(MIDITrack(removeDuplicates, deinterleave))
# Public Functions. These (for the most part) wrap the MIDITrack
# functions, where most Processing takes place.
def addNote(self, track, channel, pitch, time, duration, volume):
"""
Add notes to the MIDIFile object
Use:
MyMIDI.addNotes(track,channel,pitch,time, duration, volume)
Arguments:
track: The track to which the note is added.
channel: the MIDI channel to assign to the note. [Integer, 0-15]
pitch: the MIDI pitch number [Integer, 0-127].
time: the time (in beats) at which the note sounds [Float].
duration: the duration of the note (in beats) [Float].
volume: the volume (velocity) of the note. [Integer, 0-127].
"""
self.tracks[track].addNoteByNumber(channel, pitch, time,
duration, volume)
def addTrackName(self, track, time, trackName):
"""
Add a track name to a MIDI track.
Use:
MyMIDI.addTrackName(track,time,trackName)
Argument:
track: The track to which the name is added. [Integer, 0-127].
time: The time at which the track name is added, in beats [Float].
trackName: The track name. [String].
"""
self.tracks[track].addTrackName(time, trackName)
def addTempo(self, track, time, tempo):
"""
Add a tempo event.
Use:
MyMIDI.addTempo(track, time, tempo)
Arguments:
track: The track to which the event is added. [Integer, 0-127].
time: The time at which the event is added, in beats. [Float].
tempo: The tempo, in Beats per Minute. [Integer]
"""
self.tracks[track].addTempo(time, tempo)
def addProgramChange(self, track, channel, time, program):
"""
Add a MIDI program change event.
Use:
MyMIDI.addProgramChange(track,channel, time, program)
Arguments:
track: The track to which the event is added. [Integer, 0-127].
channel: The channel the event is assigned to. [Integer, 0-15].
time: The time at which the event is added, in beats. [Float].
program: the program number. [Integer, 0-127].
"""
self.tracks[track].addProgramChange(channel, time, program)
def addControllerEvent(self, track, channel, time, eventType, paramerter1):
"""
Add a MIDI controller event.
Use:
MyMIDI.addControllerEvent(track, channel, time,
eventType, parameter1)
Arguments:
track: The track to which the event is added. [Integer, 0-127].
channel: The channel the event is assigned to. [Integer, 0-15].
time: The time at which the event is added, in beats. [Float].
eventType: the controller event type.
parameter1: The event's parameter. The meaning of which
varies by event type.
"""
self.tracks[track].addControllerEvent(channel, time,
eventType, paramerter1)
def changeNoteTuning(self, track, tunings, sysExChannel=0x7F,
realTime=False, tuningProgam=0):
"""
Change a note's tuning using SysEx change tuning program.
Use:
MyMIDI.changeNoteTuning(track,[tunings],realTime=False,
tuningProgram=0)
Arguments:
track: The track to which the event is added. [Integer, 0-127].
tunings: A list of tuples in the form (pitchNumber, frequency).
[[(Integer,Float]]
realTime: Boolean which sets the real-time flag. Defaults to false.
sysExChannel: do note use (see below).
tuningProgram: Tuning program to assign. Defaults to
zero. [Integer, 0-127]
In general the sysExChannel should not be changed (parameter
will be depreciated).
Also note that many software packages and hardware packages do
not implement this standard!
"""
self.tracks[track].changeNoteTuning(tunings, sysExChannel, realTime,
tuningProgam)
def writeFile(self, fileHandle):
'''
Write the MIDI File.
Use:
MyMIDI.writeFile(filehandle)
Arguments:
filehandle: a file handle that has been opened for binary writing.
'''
self.header.writeFile(fileHandle)
# Close the tracks and have them create the MIDI event data
# structures.
self.close()
# Write the MIDI Events to file.
for i in range(0, self.numTracks):
self.tracks[i].writeTrack(fileHandle)
def addSysEx(self, track, time, manID, payload):
"""
Add a SysEx event
Use:
MyMIDI.addSysEx(track,time,ID,payload)
Arguments:
track: The track to which the event is added. [Integer, 0-127].
time: The time at which the event is added, in beats. [Float].
ID: The SysEx ID number
payload: the event payload.
Note: This is a low-level MIDI function, so care must be used in
constructing the payload. It is recommended that higher-level helper
functions be written to wrap this function and construct the payload if
a developer finds him or herself using the function heavily.
"""
self.tracks[track].addSysEx(time, manID, payload)
def addUniversalSysEx(self, track, time, code, subcode, payload,
sysExChannel=0x7F, realTime=False):
"""
Add a Universal SysEx event.
Use:
MyMIDI.addUniversalSysEx(track, time, code, subcode, payload,\
sysExChannel=0x7f, realTime=False)
Arguments:
track: The track to which the event is added. [Integer, 0-127].
time: The time at which the event is added, in beats. [Float].
code: The even code. [Integer]
subcode The event sub-code [Integer]
payload: The event payload. [Binary string]
sysExChannel: The SysEx channel.
realTime: Sets the real-time flag. Defaults to zero.
Note: This is a low-level MIDI function, so care must be used
in constructing the payload. It is recommended that
higher-level helper functions be written to wrap this function
and construct the payload if a developer finds him or herself
using the function heavily. As an example of such a helper
function, see the changeNoteTuning function, both here and in
MIDITrack.
"""
self.tracks[track].addUniversalSysEx(time, code, subcode, payload,
sysExChannel, realTime)
def shiftTracks(self, offset=0):
"""
Shift tracks to be zero-origined, or origined at offset.
Note that the shifting of the time in the tracks uses the
MIDIEventList -- in other words it is assumed to be called in
the stage where the MIDIEventList has been created. This
function, however, it meant to operate on the eventList
itself.
"""
origin = 1000000 # A little silly, but we'll assume big enough
for track in self.tracks:
if len(track.eventList) > 0:
for event in track.eventList:
if event.time < origin:
origin = event.time
for track in self.tracks:
tempEventList = []
for event in track.eventList:
adjustedTime = event.time - origin
event.time = adjustedTime + offset
tempEventList.append(event)
track.eventList = tempEventList
# End Public Functions ########################
def close(self):
'''
Close the MIDIFile for further writing.
To close the File for events, we must close the tracks, adjust
the time to be zero-origined, and have the tracks write to
their MIDI Stream data structure.
'''
if self.closed:
return
for i in range(0, self.numTracks):
self.tracks[i].closeTrack()
# We want things like program changes to come before notes
# when they are at the same time, so we sort the MIDI
# events by their ordinality
self.tracks[i].MIDIEventList.sort()
origin = self.findOrigin()
for i in range(0, self.numTracks):
self.tracks[i].adjustTime(origin)
self.tracks[i].writeMIDIStream()
self.closed = True
def findOrigin(self):
'''
Find the earliest time in the file's tracks.append.
'''
origin = 1000000 # A little silly, but we'll assume big enough
# Note: This code assumes that the MIDIEventList has been
# sorted, so this should be insured before it is
# called. It is probably a poor design to do this.
# TODO: Consider making this less efficient but more robust
# by not assuming the list to be sorted.
for track in self.tracks:
if len(track.MIDIEventList) > 0:
if track.MIDIEventList[0].time < origin:
origin = track.MIDIEventList[0].time
return origin
def writeVarLength(i):
'''
Accept an input, and write a MIDI-compatible variable length
stream
The MIDI format is a little strange, and makes use of so-called
variable length quantities. These quantities are a stream of
bytes. If the most significant bit is 1, then more bytes
follow. If it is zero, then the byte in question is the last in
the stream
'''
input = int(i)
output = [0, 0, 0, 0]
reversed = [0, 0, 0, 0]
count = 0
result = input & 0x7F
output[count] = result
count = count + 1
input = input >> 7
while input > 0:
result = input & 0x7F
result = result | 0x80
output[count] = result
count = count + 1
input = input >> 7
reversed[0] = output[3]
reversed[1] = output[2]
reversed[2] = output[1]
reversed[3] = output[0]
return reversed[4-count:4]
def frequencyTransform(freq):
'''
Returns a three-byte transform of a frequencyTransform
'''
resolution = 16384
freq = float(freq)
dollars = 69 + 12 * math.log(freq/(float(440)), 2)
firstByte = int(dollars)
lowerFreq = 440 * pow(2.0, ((float(firstByte) - 69.0)/12.0))
if freq != lowerFreq:
centDif = 1200 * math.log((freq/lowerFreq), 2)
else:
centDif = 0
cents = round(centDif/100 * resolution) # round?
secondByte = min([int(cents) >> 7, 0x7F])
thirdByte = cents - (secondByte << 7)
thirdByte = min([thirdByte, 0x7f])
if thirdByte == 0x7f and secondByte == 0x7F and firstByte == 0x7F:
thirdByte = 0x7e
thirdByte = int(thirdByte)
return [firstByte, secondByte, thirdByte]
def returnFrequency(freqBytes):
'''
The reverse of frequencyTransform. Given a byte stream, return a
frequency.
'''
resolution = 16384.0
baseFrequency = 440 * pow(2.0, (float(freqBytes[0]-69.0)/12.0))
frac = (float((int(freqBytes[1]) << 7) +
int(freqBytes[2])) * 100.0) / resolution
frequency = baseFrequency * pow(2.0, frac/1200.0)
return frequency