Music21#
https://www.music21.org/music21docs/usersGuide/
Note class#
name: e.g.
'F'octave: e.g.
5(ISO)pitch: e.g.
'F5','B-2','D#3'
Maybe it would make more sense to have an alter (alteration)? Music21 uses, e.g.
bflat.pitch.accidental.alter == -1, so alterations are actually objects, maybe
because they have some interesting attributes like position ‘left’ or ‘above’
Canonical note representation could be:
* <start, duration, pitch, lyric> (see Pitch and Duration below)
derived from this are:
* name_with_octave
* pitch_class
* frequency
* alter_name
* key_number (or maybe midi)
* unicode_name
* unicode_name_with_octave
methods include:
* enharmonic()
* lower_enharmonic()
* upper_enharmonic()
Rests class - another class. Accessing pitch gives an exception
For convenience, Note has a lot of methods, but Note should be composed of:
* <start, duration, pitch, tie>, where tie is 'start', 'stop', or 'continue' (both)
Pitch is <name, octave, alter>
and derived are:
* name_with_octave
* pitch_class
* frequency
* alter_name
* key_number (or maybe midi)
* unicode_name
* unicode_name_with_octave
methods include:
* enharmonic()
* lower_enharmonic()
* upper_enharmonic()
- Duration using rationals - see fractions.py
measured in quarters
properties are:
* quarters
Structure#
Stream is supertype for Score, Part and Measure
Streams have time (delta) and a list of components:
* Stream
* Note
* Chord
* Clef
* TimeSignature
* Rest?
Component deltas are relative to the parent, not global. We can add a tempo curve that consists of breakpoints
starting at (0,0), and map seconds to quarters Operations could then include: fix the tempo, e.g. linear mapping at some number of quarters/second; convert internal deltas from quarters to seconds; convert internal deltas from seconds to quarters.
- Ties: in Music21, notes can have durations that take
them out of the measure, OR notes can have ties.
Chord#
similar to Note, but it has pitches instead of pitch
methods include:
* root
* bass
Tempo#
not in Music21 - should add tempo curve to Stream