miditk-smf 0.2.2

Quickstart

Install:

$ pip install miditk-smf

Usage:

from miditk.smf import MidiFileWriter

# Open file for writing in binary mode.
with open('minimal.mid', 'wb') as smf:
    # Create standard MIDI file writer.
    midi = MidiFileWriter(smf)

    # Write file and track header for Type 0 file, one track, 96 pulses per
    # quarter note (ppqn). These are also the default parameter values.
    midi.header(format=0, num_tracks=1, tick_division=96)
    midi.start_of_track()

    # Set tempo to 120 bpm in µsec per quarter note.
    # When no tempo is set in the MIDI file, sequencers will generally assume
    # it to be 120 bpm.
    midi.tempo(int(60000000 / 120))

    # Add MIDI events.
    midi.note_on(channel=0, note=0x40)
    # Advance 192 ticks (i.e. a half note).
    midi.update_ticks(192)
    midi.note_off(channel=0, note=0x40)

    # End track and midi file.
    midi.end_of_track()
    midi.eof()

For more examples, see 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 planned packages under the common top-level package namespace miditk. This package mainly provides the miditk.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.

Installation

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

$ pip install miditk-smf

It is provided as a source distribution and a universal Python wheel for all supported Python versions and operating systems. It only depends on the Python standard library and the third-party module six.

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.writer

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.

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)

import sys
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, note, velocity):
        super().note_on(self, channel, min(127, note + 12), velocity)

    def note_off(self, channel, note, velocity):
        super().note_off(self, channel, min(127, note + 12), velocity)

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

# Create the parser and event handler
with open(outfile, 'wb') as smf:
    midiout = Transposer(smf)
    midiin = MidiFileReader(infile, midiout)

    # Now do the processing.
    midiin.read()

Development

Clone the repo:

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

Install tox:

$ pip install tox

Or via your Linux distribution package manager, e.g. on debian/Ubuntu:

$ sudo apt-get install python-tox

Or on Arch Linux:

$ sudo pacman -S python-tox

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

$ tox

If all is well, create a new git branch and start hacking and then contribute your changes by opening a pull request on GitHub.

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 maxm@maxm.dk.