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Tuning and Microtonalities
==========================
.. currentmodule:: midiutil.MidiFile
One of my interests is microtonalities/non-standard tunings, so support
for such explorations has been included in the library.
There are several ways that tuning data can be specified in the MIDI standard,
two of the most common being note pitch-bend and bulk tuning dumps. In this
library I have implemented the real-time change note tuning of the MIDI
tuning standard. I chose that as a first implementation because most of the
soft-synthesizers I use support this standard.
Note, however, that implementation of the MIDI tuning standard is somewhat spotty,
so you may want to verify that your hardware and/or software supports it before
you spend too much time.
Recently the pitch bend message had been implemented. The advantage of the pitch
bend is that almost all software and hardware understand it. The disadvantage is that
different software and hardware can interpret the values differently.
The main function to support a tuning change is ``changeNoteTuning``.
.. automethod:: MIDIFile.changeNoteTuning
Tuning Program
--------------
With some instruments, such as `timidity <http://timidity.sourceforge.net/>`_, this
is all you need to do: timidity will apply the tuning change to the notes.
Other instruments, such as `fluidsynth <http://www.fluidsynth.org/>`_, require
that the tuning program be explicitly assigned. This is done with the
``changeTuningProgram`` function:
.. automethod:: MIDIFile.changeTuningProgram
Tuning Bank
-----------
The tuning bank can also be specified (fluidsynth assumes that any tuning
you transmit via ``changeNoteTuning`` is assigned to bank zero):
.. automethod:: MIDIFile.changeTuningBank
An Example
----------
So, as a complete example, the following code fragment would get rid of that
pesky 440 Hz A and tell the instrument to use the tuning that you just
transmitted:
.. code:: python
track = 0
channel = 0
tuning = [(69, 500)]
program = 0
bank = 0
time = 0
MyMIDI.changeNoteTuning(track, tuning, tuningProgam=program)
MyMIDI.changeTuningBank(track, channel, time, bank) # may or may not be needed
MyMIDI.changeTuningProgram(track, channel, time, program) # ditto
Using Pitch Bend
----------------
Pitch bend is a *channel level event*, meaning that if you pass a pitch wheel event, all
notes on that channel will be affected.
.. automethod:: MIDIFile.addPitchWheelEvent
To Do
-----
* Implement the tuning change with bank select event type.
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