music21.audioSearch.scoreFollower

ScoreFollower

class music21.audioSearch.scoreFollower.ScoreFollower(scoreStream=None)

ScoreFollower methods

ScoreFollower.getFirstSlotOnScreen()

Returns the index of the first element on the screen right now.

Doesn’t work. (maybe it’s not necessary)

ScoreFollower.matchingNotes(scoreStream, transcribedScore, notePrediction, lastNotePosition)

ScoreFollower.predictNextNotePosition(totalLengthPeriod, totalSeconds)

It predicts the position in which the first note of the following recording note should start, taking into account the processing time of the computer. It has two inputs: totalLengthPeriod, that is the number of pulses or beats in the recorded audio, and totalSeconds, that is the length in seconds of the processing time.

It returns a number with the position of the predicted note in the score.

>>> from time import time
>>> from music21.audioSearch import scoreFollower
>>> scNotes = corpus.parse('luca/gloria').parts[0].flatten().notes.stream()
>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> ScF.scoreNotesOnly = ScF.scoreStream.flatten().notesAndRests
>>> ScF.lastNotePosition = 14
>>> ScF.seconds_recording = 10.0
>>> totalLengthPeriod = 8
>>> totalSeconds = 2.0
>>> predictedStartPosition = ScF.predictNextNotePosition(
...     totalLengthPeriod, totalSeconds)
>>> print(predictedStartPosition)
18

ScoreFollower.repeatTranscription()

First, it records from the microphone (or from a file if is used for test). Later, it processes the signal in order to detect the pitches. It converts them into music21 objects and compares them with the score. It finds the best matching position of the recorded signal with the score, and decides, depending on matching accuracy, the last note predicted and some other parameters, in which position the recorded signal is.

It returns a value that is False if the song has not finished, or true if there has been a problem like some consecutive bad matchings or the score has finished.

>>> from music21.audioSearch import scoreFollower
>>> scoreNotes = ' '.join(['c4', 'd', 'e', 'f', 'g', 'a', 'b', "c'", 'c', 'e',
...     'g', "c'", 'a', 'f', 'd', 'c#', 'd#', 'f#', 'c', 'e', 'g', "c'",
...     'a', 'f', 'd', 'c#', 'd#', 'f#'])
>>> scNotes = converter.parse('tinynotation: 4/4 ' + scoreNotes, makeNotation=False)
>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> ScF.useMic = False
>>> ScF.waveFile = 'test_audio.wav'
>>> ScF.seconds_recording = 10
>>> ScF.useScale = scale.ChromaticScale('C4')
>>> ScF.currentSample = 0
>>> exitType = ScF.repeatTranscription()
>>> print(exitType)
False
>>> print(ScF.lastNotePosition)
10

ScoreFollower.runScoreFollower(plot=False, useMic=False, seconds=15.0, useScale=None)

The main program. It runs the ‘repeatTranscription’ until the performance ends.

If useScale is none, then it uses a scale.ChromaticScale

ScoreFollower.silencePeriodDetection(notesList)

Detection of consecutive periods of silence. Useful if the musician has some consecutive measures of silence.

>>> from music21.audioSearch import scoreFollower
>>> scNotes = corpus.parse('luca/gloria').parts[0].flatten().notes.stream()
>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> notesList = []
>>> notesList.append(note.Rest())
>>> ScF.notesCounter = 3
>>> ScF.silencePeriodCounter = 0
>>> ScF.silencePeriodDetection(notesList)
>>> ScF.notesCounter
0
>>> ScF.silencePeriodCounter
1

>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> notesList = []
>>> notesList.append(note.Rest())
>>> notesList.append(note.Note())
>>> ScF.notesCounter = 1
>>> ScF.silencePeriodCounter = 3
>>> ScF.silencePeriodDetection(notesList)
>>> ScF.notesCounter
2
>>> ScF.silencePeriodCounter
0

ScoreFollower.updatePosition(prob, totalLengthPeriod, time_start)

It updates the position in which the scoreFollower starts to search at, and the predicted position in which the new fragment of the score should start. It updates these positions taking into account the value of the “countdown”, and if is the beginning of the song or not.

It returns the exitType, which determines whether the scoreFollower has to stop (and why) or not.

See example of a bad prediction at the beginning of the song:

>>> from time import time
>>> from music21.audioSearch import scoreFollower
>>> scNotes = corpus.parse('luca/gloria').parts[0].flatten().notes.stream()
>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> ScF.begins = True
>>> ScF.startSearchAtSlot = 15
>>> ScF.countdown = 0
>>> prob = 0.5  # bad prediction
>>> totalLengthPeriod = 15
>>> time_start = time()
>>> exitType = ScF.updatePosition(prob, totalLengthPeriod, time_start)
>>> print(ScF.startSearchAtSlot)
0

Different examples for different countdowns:

Countdown = 0:

The last matching was good, so it calculates the position in which it starts to search at, and the position in which the music should start.

>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> ScF.scoreNotesOnly = scNotes.flatten().notesAndRests
>>> ScF.begins = False
>>> ScF.countdown = 0
>>> ScF.startSearchAtSlot = 15
>>> ScF.lastNotePosition = 38
>>> ScF.predictedNotePosition = 19
>>> ScF.seconds_recording = 10
>>> prob = 0.8
>>> totalLengthPeriod = 25
>>> time_start = time()
>>> exitType = ScF.updatePosition(prob, totalLengthPeriod, time_start)
>>> print(ScF.startSearchAtSlot)
38

>>> ScF.predictedNotePosition >=38
True

Countdown = 1:

Now it doesn’t change the slot in which it starts to search at. It also predicts the position in which the music should start.

>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> ScF.begins = False
>>> ScF.countdown = 1
>>> ScF.startSearchAtSlot = 15
>>> ScF.lastNotePosition = 15
>>> ScF.predictedNotePosition = 19
>>> ScF.seconds_recording = 10
>>> prob = 0.8
>>> totalLengthPeriod = 25
>>> time_start = time()
>>> exitType = ScF.updatePosition(prob, totalLengthPeriod, time_start)
>>> print(ScF.startSearchAtSlot)
15

>>> ScF.predictedNotePosition > 15
True

Countdown = 2:

Now it starts searching at the beginning of the page of the screen. The note prediction is also the beginning of the page.

>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> ScF.begins = False
>>> ScF.countdown = 2
>>> ScF.startSearchAtSlot = 15
>>> ScF.lastNotePosition = 15
>>> ScF.predictedNotePosition = 19
>>> ScF.seconds_recording = 10
>>> prob = 0.8
>>> totalLengthPeriod = 25
>>> time_start = time()
>>> exitType = ScF.updatePosition(prob, totalLengthPeriod, time_start)
>>> print(ScF.startSearchAtSlot)
15

>>> print(ScF.predictedNotePosition)
39

Countdown = 4:

Now it starts searching at the beginning of the page of the screen. The note prediction is also the beginning of the page.

>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> ScF.begins = False
>>> ScF.countdown = 4
>>> ScF.startSearchAtSlot = 15
>>> ScF.lastNotePosition = 15
>>> ScF.predictedNotePosition = 19
>>> ScF.seconds_recording = 10
>>> prob = 0.8
>>> totalLengthPeriod = 25
>>> time_start = time()
>>> exitType = ScF.updatePosition(prob, totalLengthPeriod, time_start)
>>> print(ScF.startSearchAtSlot)
0

>>> print(ScF.predictedNotePosition)
0

Countdown = 5:

Now it stops the program.

>>> ScF = scoreFollower.ScoreFollower(scoreStream=scNotes)
>>> ScF.begins = False
>>> ScF.countdown = 5
>>> ScF.startSearchAtSlot = 15
>>> ScF.lastNotePosition = 15
>>> ScF.predictedNotePosition = 19
>>> ScF.seconds_recording = 10
>>> prob = 0.8
>>> totalLengthPeriod = 25
>>> time_start = time()
>>> exitType = ScF.updatePosition(prob, totalLengthPeriod, time_start)
>>> print(exitType)
countdownExceeded