music21j-port
Version:
A toolkit for computer-aided musicology, Javascript version
291 lines (268 loc) • 9.92 kB
JavaScript
import * as MIDI from 'midicube';
import { common } from './common.js';
/**
* audioSearch module. See {@link music21.audioSearch} namespace
*
* @exports music21/audioSearch
*/
/**
* @namespace music21.audioSearch
* @memberof music21
* @requires music21/pitch
* @requires music21/common
*/
export const audioSearch = {};
// functions based on the prototype created by Chris Wilson's MIT License version
// and on Jordi Bartolome Guillen's audioSearch module for music21
audioSearch.fftSize = 2048;
audioSearch.AudioContextCaller
= window.AudioContext || window.webkitAudioContext;
audioSearch._audioContext = null;
audioSearch.animationFrameCallbackId = null;
Object.defineProperties(audioSearch, {
audioContext: {
get: () => {
if (audioSearch._audioContext !== null) {
return audioSearch._audioContext;
} else {
// AudioContext should be a singleton, but MIDI reports loaded before it is!
if (
MIDI !== undefined
&& MIDI.WebAudio !== undefined
&& MIDI.WebAudio.getContext() !== undefined
) {
window.globalAudioContext = MIDI.WebAudio.getContext();
} else if (typeof window.globalAudioContext === 'undefined') {
window.globalAudioContext = new audioSearch.AudioContextCaller();
}
audioSearch._audioContext = window.globalAudioContext;
return audioSearch._audioContext;
}
},
set: ac => {
audioSearch._audioContext = ac;
},
},
});
/**
*
* @function music21.audioSearch.getUserMedia
* @memberof music21.audioSearch
* @param {Object} dictionary - optional dictionary to fill
* @param {function} callback - callback on success
* @param {function} error - callback on error
*/
audioSearch.getUserMedia = function getUserMedia(dictionary, callback, error) {
if (error === undefined) {
/* eslint no-alert: "off"*/
error = () => {
alert(
'navigator.getUserMedia either not defined (Safari, IE) or denied.'
);
};
}
if (callback === undefined) {
callback = mediaStream => {
audioSearch.userMediaStarted(mediaStream);
};
}
const n = navigator;
// need to polyfill navigator, or binding problems are hard...
n.getUserMedia
= n.getUserMedia
|| n.webkitGetUserMedia
|| n.mozGetUserMedia
|| n.msGetUserMedia;
if (n.getUserMedia === undefined) {
error();
}
if (dictionary === undefined) {
dictionary = {
audio: {
mandatory: {},
optional: [],
},
};
}
n.getUserMedia(dictionary, callback, error);
};
audioSearch.sampleBuffer = null;
audioSearch.currentAnalyser = null;
audioSearch.userMediaStarted = function userMediaStarted(audioStream) {
/**
* This function which patches Safari requires some time to get started
* so we call it on object creation.
*/
audioSearch.sampleBuffer = new Float32Array(audioSearch.fftSize / 2);
const mediaStreamSource = audioSearch.audioContext.createMediaStreamSource(
audioStream
);
const analyser = audioSearch.audioContext.createAnalyser();
analyser.fftSize = audioSearch.fftSize;
mediaStreamSource.connect(analyser);
audioSearch.currentAnalyser = analyser;
audioSearch.animateLoop();
};
audioSearch.minFrequency = 55;
audioSearch.maxFrequency = 1050;
audioSearch.animateLoop = function animateLoop(time) {
audioSearch.currentAnalyser.getFloatTimeDomainData(
audioSearch.sampleBuffer
);
// returns best frequency or -1
const frequencyDetected = audioSearch.autoCorrelate(
audioSearch.sampleBuffer,
audioSearch.audioContext.sampleRate,
audioSearch.minFrequency,
audioSearch.maxFrequency
);
const retValue = audioSearch.sampleCallback(frequencyDetected);
if (retValue !== -1) {
audioSearch.animationFrameCallbackId = window.requestAnimationFrame(
audioSearch.animateLoop
);
}
};
audioSearch.pitchSmoothingSize = 40;
audioSearch.lastPitchClassesDetected = [];
audioSearch.lastPitchesDetected = [];
audioSearch.lastCentsDeviationsDetected = [];
audioSearch.smoothPitchExtraction = function smoothPitchExtraction(frequency) {
if (frequency === -1) {
audioSearch.lastPitchClassesDetected.shift();
audioSearch.lastPitchesDetected.shift();
audioSearch.lastCentsDeviationsDetected.shift();
} else {
const [midiNum, centsOff] = audioSearch.midiNumDiffFromFrequency(
frequency
);
if (
audioSearch.lastPitchClassesDetected.length
> audioSearch.pitchSmoothingSize
) {
audioSearch.lastPitchClassesDetected.shift();
audioSearch.lastPitchesDetected.shift();
audioSearch.lastCentsDeviationsDetected.shift();
}
audioSearch.lastPitchClassesDetected.push(midiNum % 12);
audioSearch.lastPitchesDetected.push(midiNum);
audioSearch.lastCentsDeviationsDetected.push(centsOff);
}
const mostCommonPitchClass = common.statisticalMode(
audioSearch.lastPitchClassesDetected
);
if (mostCommonPitchClass === null) {
return [-1, 0];
}
const pitchesMatchingClass = [];
const centsMatchingClass = [];
for (let i = 0; i < audioSearch.lastPitchClassesDetected.length; i++) {
if (audioSearch.lastPitchClassesDetected[i] === mostCommonPitchClass) {
pitchesMatchingClass.push(audioSearch.lastPitchesDetected[i]);
centsMatchingClass.push(audioSearch.lastCentsDeviationsDetected[i]);
}
}
const mostCommonPitch = common.statisticalMode(pitchesMatchingClass);
// find cents difference; weighing more recent samples more...
let totalSamplePoints = 0;
let totalSample = 0;
for (let j = 0; j < centsMatchingClass.length; j++) {
const weight = Math.pow(j, 2) + 1;
totalSample += weight * centsMatchingClass[j];
totalSamplePoints += weight;
}
const centsOff = Math.floor(totalSample / totalSamplePoints);
return [mostCommonPitch, centsOff];
};
audioSearch.sampleCallback = function sampleCallback(frequency) {
const [unused_midiNum, unused_centsOff] = audioSearch.smoothPitchExtraction(
frequency
);
};
// from Chris Wilson. Replace with Jordi's
audioSearch.autoCorrelate = function autoCorrelate(
buf,
sampleRate,
minFrequency,
maxFrequency
) {
const SIZE = buf.length;
const MAX_SAMPLES = Math.floor(SIZE / 2);
if (minFrequency === undefined) {
minFrequency = 0;
}
if (maxFrequency === undefined) {
maxFrequency = sampleRate;
}
let best_offset = -1;
let best_correlation = 0;
let rms = 0;
let foundGoodCorrelation = false;
const correlations = new Array(MAX_SAMPLES);
for (let i = 0; i < SIZE; i++) {
const val = buf[i];
rms += val * val;
}
rms = Math.sqrt(rms / SIZE);
if (rms < 0.01) {
return -1;
} // not enough signal
let lastCorrelation = 1;
for (let offset = 0; offset < MAX_SAMPLES; offset++) {
let correlation = 0;
const offsetFrequency = sampleRate / offset;
if (offsetFrequency < minFrequency) {
break;
}
if (offsetFrequency > maxFrequency) {
continue;
}
for (let i = 0; i < MAX_SAMPLES; i++) {
correlation += Math.abs(buf[i] - buf[i + offset]);
}
correlation = 1 - correlation / MAX_SAMPLES;
correlations[offset] = correlation; // store it, for the tweaking we need to do below.
if (correlation > 0.9 && correlation > lastCorrelation) {
foundGoodCorrelation = true;
if (correlation > best_correlation) {
best_correlation = correlation;
best_offset = offset;
}
} else if (foundGoodCorrelation) {
// short-circuit - we found a good correlation, then a bad one, so we'd just be seeing copies from here.
// Now we need to tweak the offset - by interpolating between the values to the left and right of the
// best offset, and shifting it a bit. This is complex, and HACKY in this code (happy to take PRs!) -
// we need to do a curve fit on correlations[] around best_offset in order to better determine precise
// (anti-aliased) offset.
// we know best_offset >=1,
// since foundGoodCorrelation cannot go to true until the second pass (offset=1), and
// we can't drop into this clause until the following pass (else if).
const shift
= (correlations[best_offset + 1]
- correlations[best_offset - 1])
/ correlations[best_offset];
return sampleRate / (best_offset + 8 * shift);
}
lastCorrelation = correlation;
}
if (best_correlation > 0.01) {
// console.log("f = " + sampleRate/best_offset + "Hz (rms: " + rms + " confidence: " + best_correlation + ")")
return sampleRate / best_offset;
}
return -1;
// var best_frequency = sampleRate/best_offset;
};
/**
*
* @function midiNumDiffFromFrequency
* @param {Number} frequency
* @returns {Array<int>} [miniNumber, centsOff]
*/
audioSearch.midiNumDiffFromFrequency = function midiNumDiffFromFrequency(
frequency
) {
const midiNumFloat = 12 * (Math.log(frequency / 440) / Math.log(2)) + 69;
const midiNum = Math.round(midiNumFloat);
const centsOff = Math.round(100 * (midiNumFloat - midiNum));
return [midiNum, centsOff];
};