miditk-smf 0.1.0

A toolkit for working with Standard MIDI files

A toolkit for working with Standard MIDI files

Quickstart

Clone the repo:

$ git clone https://github.com/SpotlightKid/miditk-smf.git
$ cd miditk-smf

Install tox:

$ sudo apt-get install python-tox

Run the tests via tox for all Python versions configured in tox.ini:

$ tox

If all is well, continue to the Usage examples section below.

Overview

miditk-smf is a general-purpose library for the parsing and generation of Standard MIDI Files (SMF). The package is part of several packages under the common top-level package namespace miditk. This package mainly provides the midi.smf sub-package for handling standard MIDI files. Additional sub-packages with more specialised MIDI libraries and tools will be distributed as separate package distributions in the future.

Compatibility

miditk-smf works with Python 2.7, Python 3.4+ and PyPy 2 and 3.

Installation

miditk-smf is installable via pip from the Python Package Index:

$ pip install miditk-smf

It is provided as a source distribution and as Python wheels for different Python versions and operating systems.

Package contents

miditk.common

A collection of constants from the MIDI specification used by sub-packages and general data types for working with MIDI events.

miditk.smf

An event-based standard MIDI file (SMF) parsing and generation framework.

miditk.smf.api

Base event handler classes, which can be sublassed for specialised event handling.

miditk.smf.converters

A collection of functions that converts the special data types used in midi files to and from byte strings.

miditk.smf.parser

The main binary MIDI file data parser.

miditk.smf.reader

Combines the parser with an event handler class.

miditk.smf.sequence

An event handler, which stores all MIDI events from a MIDI file in a MidiSequence container class.

miditk.smf.sequence

An event handler to write out MIDI events to a Standard MIDI File.

Usage examples

The following section contains a few code examples, which demonstrate several usage scenarios for the different modules in the package. For more examples see also the scripts in the examples directory of the source distribution.

Parsing a standard MIDI file

The miditk.smf module provides the MidiSequence container class, which uses its own MIDI event handler class to collect all information and events from parsing a midi file. Use the MidiSequence.fromfile() class method to parse a standard MIDI file.

You can then use several convenience methods of the returned MidiSequence instance to access information about the midi file properties or events.

from miditk.smf import MidiSequence

# do parsing
sequence = MidiSequence.fromfile(sys.argv[1])

# print some info from the MIDI file header,
# e.g. number of tracks, events sequence name
print(sequence)
# print a list of events with event type, data and timestamp
sequence.dump_events()

# iterate over all sysex events in track 0
# if track is not specified, sysex_events() yields all sysex events
# in all tracks
for ev in sequence.sysex_events(track=0):
    print "Sysex event (%i bytes) @ %.2f" (len(ev.data), ev.timestamp)

# iterate over all events sorted by timestamp and then track
for ev in sequence.events_by_time():
    handle_event(ev)

Changing MIDI events in-stream

The event-based parsing allows to handle MIDI events as they are read (or received via MIDI in). You need to define a sub-class of miditk.smf.BaseMidiEventHandler or miditk.smf.NullMidiEventHandler and overwrite only the event handling methods for the events you are interested in.

The following example transposes all note on/off events by an octave (i.e. 12 semitones):

from miditk.smf import MidiFileReader, MidiFileWriter

# MidiFileWriter is a sub-class of NullMidiEventHandler
class Transposer(MidiFileWriter):
    """Transpose note values of all note on/off events by 1 octave."""

    def note_on(self, channel=0, note=60, vel=64):
        super().note_on(self, channel, min(127, note + 12), vel)

    def note_off(self, channel=0, note=60, vel=64):
        super().note_off(self, channel, min(127, note + 12), vel)

infile = sys.argv.pop(1)
outfile = sys.argv.pop(1)

# create event handlers
midiout = Transposer(outfile)
midiin = MidiFileReader(infile, midiout)

# now do the processing
midiin.read()

Code QA

The included Makefile is set up to run several Python static code checking and reporting tools. To print a list of available Makefile targets and the tools they run, simple run:

$ make

Then run the Makefile target of your choice, e.g.:

$ make flake8

Unless noted otherwise, these targets run all tools directly, i.e. without tox, which means they need to be installed in your Python environment, preferably in a project-specific virtual environment. To create a virtual environment and install all supported tools and their dependencies run:

$ mkvirtualenv miditk-smf
(miditk-smf)$ pip install -r requirements/dev.txt

Documentation

Package documentation is generated by Sphinx. The documentation can be build with:

$ make docs

After a successful build the documentation index is opened in your web browser.

Authors and License

The miditk package is written by Christopher Arndt and licensed under the MIT License.

The the structure of the miditk.smf sub-package ows inspiration to the python midi package, written by [e-mail].