In [3]:
music.show()
# This command show the beginning of the sheet music.
(version 2022_01_03)
Table of contents:
This tutorial explains how to use Music21 to search for a melodic motif in a piece and how to display the exact positions of the instances (voice, measure, beat).
As always, you first start the program and load the piece to be analyzed under a freely chosen variable name ('music'). We choose the Kyrie from the mass "Missa La sol fa re mi" by Josquin (Jos1102) to search for the sequence of notes "La sol fa re mi" (= A G F D E):
from music21 import *
# with this command ('Run'-Button!) the music21 library will be loaded.
# This command must ALWAYS be started when working with a notebook.
music = converter.parse('https://analyse.hfm-weimar.de/database/02/PrJode_Jos1102_COM_1-5_MissaLasol_002_00137.xml')
# The Kyrie sentence is now internally labeled as variable 'music.
music.show()
# This command show the beginning of the sheet music.
music.show('midi')
# or opened as audio (midi) in the browser (Firefox and Chrome only!).
Now we have to enter the motif we want to search for. To do this, we need to create a so-called stream (i.e. a sequence of notes), which we call "StreamMot". We are looking for the "La Sol Fa Re Mi" (= A G F D E) motif. For this we enter it through the internal notation of music21:
StreamMot = stream.Stream()
StreamMot.append(note.Note('A'))
StreamMot.append(note.Note('G'))
StreamMot.append(note.Note('F'))
StreamMot.append(note.Note('D'))
StreamMot.append(note.Note('E'))
StreamMot.show()
# a 4/4 time signature and quarter notes are used as default setting.
Since we only want to search for a pitch sequence independent of the rhythm, the rhythm entered in our search motif must be ignored. The 'recurse' command filters out all features except the pitches from the file; the result of this filtering is a sequence of notes as the variable 'full_piece_stream'.
full_piece_stream = music.recurse().notes
Now the search for the melodic line of the motif is created by the "search.noteNameSearch" function
p_full_piece = search.noteNameSearch(full_piece_stream, StreamMot)
p_full_piece
[0, 5, 41, 84, 89, 94, 356, 417, 422, 427, 447, 452, 469, 475, 492, 497, 502]
The positions of the output tones are listed (as 'p_full_piece'). This list can be further processed in several ways:
len(p_full_piece)
17
for Part in music.getElementsByClass('Part'):
curr_part_r = Part.recurse().notes
p_curr_part = search.noteNameSearch(curr_part_r, StreamMot)
print('%9s: %2d' %(Part.partName, len(p_curr_part)))
Superius: 6
Altus: 0
Tenor: 4
Bassus: 7
p_full_piece[3]
84
This means that the fourth element of the list 'p_full_piece' is the 84th note in the stream 'StreamMot' (the list with the notes of the piece). If you put this again in square brackets you get more info:
full_piece_stream[p_full_piece[3]]
<music21.note.Note A>
It was to be expected that it is the note A (initial note of our search motive). More important is the measure and the exact position of the beginning of the motif as well as the voice:
full_piece_stream[p_full_piece[3]].measureNumber
42
full_piece_stream[p_full_piece[3]].beat
1.0
full_piece_stream[p_full_piece[3]].getContextByClass('Part')
<music21.stream.Part Superius>
We can verify this by looking at the score, measure 42.
music.measures(42,43).show()
zähler=1
for Position in p_full_piece:
startingNote=full_piece_stream[Position]
startingMeasure = startingNote.measureNumber
startingBeat = startingNote.beat
startingPart = startingNote.getContextByClass('Part')
print('%2s %3s %3s' %(zähler, startingNote.nameWithOctave, startingMeasure), startingBeat, startingPart)
zähler+=1
1 A4 1 1.0 <music21.stream.Part Superius> 2 A4 3 2.0 <music21.stream.Part Superius> 3 A4 14 1.0 <music21.stream.Part Superius> 4 A4 42 1.0 <music21.stream.Part Superius> 5 A4 43 1.5 <music21.stream.Part Superius> 6 A4 44 1.5 <music21.stream.Part Superius> 7 A3 20 1.0 <music21.stream.Part Tenor> 8 A3 52 1.5 <music21.stream.Part Tenor> 9 A3 53 1.5 <music21.stream.Part Tenor> 10 A3 54 1.5 <music21.stream.Part Tenor> 11 A3 9 1.0 <music21.stream.Part Bassus> 12 A3 11 2.0 <music21.stream.Part Bassus> 13 A3 29 1.0 <music21.stream.Part Bassus> 14 A3 32 1.0 <music21.stream.Part Bassus> 15 A3 45 1.0 <music21.stream.Part Bassus> 16 A3 46 1.5 <music21.stream.Part Bassus> 17 A3 47 1.5 <music21.stream.Part Bassus>
for found in p_full_piece:
for ffound in range(len(StreamMot)):
full_piece_stream[found+ffound].lyric = '*'
full_piece_stream[found+ffound].style.color='red'
# Here the color red ('red') was chosen.
# Try another color!
music.show()
You can write the marked version of the score to a new file, whose path is depicted in the output cell and which you can in turn open with MuseScore:
music.write()
# Alternatively, you can specify your own path and name, see above, e.g.:
# music.write(fp="D:/Dokumente/josquin_markiert.xml")
# To do this, you must delete the hash before the command and enter a local path on your computer.
WindowsPath('C:/Fellowship/tmp7qvsn9c0.xml')
In Music21, a command can be programmed to search for chromatic transpositions of a motif in one fell swoop. First we need the following command:
def pitchClassEqual(n1, n2):
if not hasattr(n1, 'pitch'):
return False
if not hasattr(n2, 'pitch'):
return False
if n1.pitch.pitchClass == n2.pitch.pitchClass:
return True
else:
return False
In the following, we will search for the motif in the 12 keys (and their respective enharmonic equivalents). To do this, one must create an algorithm that is repeated 12 times. A second loop helps to enter the information from each repetition into the results list.
results = []
zähler = 1
# The results must be entered in an extra list ("results").
# The "counter" simplifies the enumeration of the tones when you want to show them one after the other.
for egal in range(12):#Suche 12 Mal
s_len = [StreamMot.notes[i].name for i in range (len(StreamMot.notes))]
print("------------\nSearching for:", *s_len, sep=' ')
p = search.streamSearchBase(full_piece_stream, StreamMot, algorithm=pitchClassEqual)
for notePosition in p:
startingNote=full_piece_stream[notePosition]
startingMeasure = startingNote.measureNumber
startingBeat = startingNote.beat
startingPart = startingNote.getContextByClass('Part')
results.append(notePosition)
print('%2s %3s %3s' %(zähler, startingNote.nameWithOctave, startingMeasure), startingBeat, startingPart.id)
zähler+=1
[n.transpose(1, inPlace=True) for n in StreamMot]
# After each search, everything is transposed up half a tone
------------ Searching for: A G F D E 1 A4 1 1.0 Superius 2 A4 3 2.0 Superius 3 A4 14 1.0 Superius 4 A4 42 1.0 Superius 5 A4 43 1.5 Superius 6 A4 44 1.5 Superius 7 A3 20 1.0 Tenor 8 A3 52 1.5 Tenor 9 A3 53 1.5 Tenor 10 A3 54 1.5 Tenor 11 A3 9 1.0 Bassus 12 A3 11 2.0 Bassus 13 A3 29 1.0 Bassus 14 A3 32 1.0 Bassus 15 A3 45 1.0 Bassus 16 A3 46 1.5 Bassus 17 A3 47 1.5 Bassus ------------ Searching for: B- G# F# E- F ------------ Searching for: B A G E F# ------------ Searching for: C B- G# F G ------------ Searching for: C# B A F# G# ------------ Searching for: D C B- G A 18 D3 36 1.0 Bassus 19 D3 39 1.0 Bassus ------------ Searching for: E- C# B G# B- ------------ Searching for: E D C A B 20 E4 9 1.0 Altus 21 E4 15 1.0 Altus 22 E4 26 1.0 Altus 23 E4 5 1.0 Tenor 24 E4 7 2.0 Tenor 25 E4 11 1.0 Tenor 26 E4 48 1.0 Tenor 27 E4 49 1.5 Tenor 28 E4 50 1.5 Tenor 29 E4 51 1.5 Tenor 30 E4 55 1.5 Tenor 31 E4 56 1.5 Tenor 32 E4 57 1.5 Tenor 33 E3 21 1.0 Bassus 34 E3 25 1.0 Bassus ------------ Searching for: F E- C# B- C ------------ Searching for: F# E D B C# ------------ Searching for: G F E- C D ------------ Searching for: G# F# E C# E-
print(len(results))
34
Now load the other movements of the Missa one after the other and look for the motif! You can use this notebook for this purpose:
How often does the motif appear in the other sentences? In which voices?