visualizer-micro.js

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.VisualizerMicro = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
/*
MIT License

Copyright (c) 2015 Christopher Dolphin

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

*/
var VisualizerMicro;

(function(){

    var AudioContext = window.AudioContext || window.webkitAudioContext,
        _warnNotSupported,
        _warnAudioLoaded,
        _volumeToDB,
        _dbToVolume,
        _onLoad,
        load,
        unload,
        isSupported,
        getSpectrum,
        getWaveform,
        setVolumeModifier,
        logPrefix = 'VisualizerMicro: ',
        loadEventString = 'canplay',
        prototype;

    VisualizerMicro = function () {
        if (!isSupported()) {
            _warnNotSupported();
            return;
        }

        this.alreadyLoaded = false;
        this.binCount = false;
        this.loadEventListenerCreated = false;
        this.loadedCallback = false;
        this.audioSource = false;
        this.dataArray = [];
    };

    _warnNotSupported = function () {
        console.warn(logPrefix + 'Audio visualization is not supported in this browser.');
    };

    _warnAudioLoaded = function () {
        console.warn(logPrefix + "An audio source must be loaded using load() before audio data can be retrieved.");
    };

    _onLoad = function () {

        if (this.alreadyLoaded) {
            return;
        }
        var source = this.context.createMediaElementSource(this.audioSource);

        source.connect(this.analyser);

        this.analyser.connect(this.context.destination);
        this.binCount = this.analyser.frequencyBinCount;
        this.dataArray = new Uint8Array(this.binCount);

        this.alreadyLoaded = true;
        this.loadedCallback();
    };

    load = function (audio, callback) {

        if (!isSupported()) {
            _warnNotSupported();
            return;
        }

        if (!audio) {
            console.warn(logPrefix + 'An audio source must be supplied to load().');
            return;
        }

        if (!callback) {
            console.warn(logPrefix + 'A callback must be supplied to load().');
            return;
        }

        if (this.audioSource === audio) {
            console.log(logPrefix + 'This audio source has already been loaded, no need to call load() with it again.');
            return;
        }

        if (this.loadEventListenerCreated && this.alreadyLoaded) {
            // remove old audio source so new one can be attached
            unload();
        }

        this.context = new AudioContext();
        this.analyser = this.context.createAnalyser();
        this.audioSource = audio;
        this.loadEventListenerCreated = true;
        this.loadedCallback = callback;

        if (audio.readyState === 3 || audio.readyState === 4) {
          this._onLoad()
        } else {
          this.audioSource.addEventListener(loadEventString, _onLoad.bind(this))
        }
    };

    unload = function () {

        if (!this.audioSource) {
            console.log(logPrefix + "Audio source doesn't exist. This may mean it was destroyed prematurely and could cause a memory leak.");
        } else {
            this.audioSource.removeEventListener(loadEventString, _onLoad);
        }

        this.alreadyLoaded = false;
        this.loadedCallback = false;
        this.loadEventListenerCreated = false;
    };

    isSupported = function () {
        return !!AudioContext;
    };

    getSpectrum = function () {

        if (!isSupported()) {
            _warnNotSupported();
            return;
        }

        if (!this.alreadyLoaded) {
            _warnAudioLoaded();
            return;
        }

        var spectrum = [],
            spectrumLength,
            minDecibels = this.analyser.minDecibels,
            maxDecibels = this.analyser.maxDecibels,
            s = 255 / (maxDecibels - minDecibels),
            dbValue;

        this.analyser.getByteFrequencyData(this.dataArray);

        spectrumLength = this.dataArray.length;

        for (var i = 0; i < spectrumLength; i++) {
            dbValue = this.dataArray[i];

            spectrum.push(dbValue / 255);
        }

        return spectrum;
    };

    getWaveform = function () {

        if (!isSupported()) {
            _warnNotSupported();
            return;
        }

        if (!this.alreadyLoaded) {
            _warnAudioLoaded();
            return;
        }

        var waveform = [],
            waveformLength,
            value;

        this.analyser.getByteTimeDomainData(this.dataArray);

        waveformLength = this.dataArray.length;

        for (var i = 0; i < waveformLength; i++) {
            value = this.dataArray[i];

            value = value - 128;
            value = value / 128;

            waveform.push(value);
        }

        return waveform;

    };

    setVolumeModifier = function (volume) {
        console.warn(logPrefix + 'Setting the volume modifier is depreciated, all spectrum values must be relative to volume from the audio source.');
    };

    //set to prototype
    prototype = VisualizerMicro.prototype;
    prototype._onLoad = _onLoad;
    prototype.load = load;
    prototype.unload = unload;
    prototype.isSupported = isSupported;
    prototype.getSpectrum = getSpectrum;
    prototype.getWaveform = getWaveform;
    prototype.setVolumeModifier = setVolumeModifier;

})();

module.exports = VisualizerMicro;

},{}]},{},[1])(1)
});