audio2wave/lib/DataProcesser.js

draw wave in canvas from audio element source

import { IEvent } from './interface/IDataProcesser';
import { Emitor } from './utils/Emitor/index';
var DEFAULT_CONFIG = {
    fftSize: 512,
};
var DataProcesser = /** @class */ (function () {
    function DataProcesser(audio, config) {
        if (config === void 0) { config = DEFAULT_CONFIG; }
        this.state = 'suspended';
        this.running = false;
        this.audio = audio;
        this.config = config;
        this.init();
    }
    DataProcesser.prototype.init = function () {
        var _this = this;
        this.emitor = new Emitor();
        this.audioContext = this.createAudioContext();
        this.audioContext.onstatechange = function (event) {
            _this.state = event.target.state;
            _this.emitor.emit('statchange', new IEvent('statechange', _this.state));
        };
        // this.audioContext.onstatechange
    };
    DataProcesser.prototype.createAudioContext = function () {
        if (window.AudioContext) {
            return new AudioContext();
        }
        else if (window.webkitAudioContext) {
            return new webkitAudioContext();
        }
        else {
            throw new Error('当前浏览器版本不支持AudioContext和webkitAudioContext，请升级或者更换浏览器');
        }
    };
    DataProcesser.prototype.createAudioSource = function (elementOrStream) {
        if (elementOrStream instanceof HTMLMediaElement) {
            return this.audioContext.createMediaElementSource(elementOrStream);
        }
        return this.audioContext.createMediaStreamSource(elementOrStream);
    };
    DataProcesser.prototype.getByteFrequenceData = function () {
        this.analyser.getByteFrequencyData(this.byteFrequencyData);
    };
    DataProcesser.prototype.start = function () {
        if (this.running)
            return Promise.reject('Processor still running');
        this.running = true;
        if (!this.analyser) {
            this.analyser = this.audioContext.createAnalyser();
            this.analyser.fftSize = this.config.fftSize || 512;
        }
        if (!this.audioSourceNode) {
            var bufferLength = this.analyser.frequencyBinCount;
            this.byteFrequencyData = new Uint8Array(bufferLength);
            this.audioSourceNode = this.createAudioSource(this.audio);
        }
        this.audioSourceNode.connect(this.analyser);
        this.analyser.connect(this.audioContext.destination);
        return this.audioContext.resume();
    };
    DataProcesser.prototype.stop = function () {
        var _this = this;
        if (!this.running)
            return Promise.reject('Processor was stoped');
        this.running = false;
        this.analyser.disconnect();
        this.audioSourceNode.disconnect();
        this.audioContext.suspend().catch(function (e) {
            _this.emitor.emit('error', new IEvent('error', e));
        }).finally(function () {
            // this.analyser = null;
            // this.audioSourceNode = null;
        });
        return Promise.resolve();
    };
    DataProcesser.prototype.destroy = function () {
        var _this = this;
        this.stop().finally(function () {
            _this.audioContext.close();
            _this.audioContext = null;
            _this.emitor.emit('destroy', new IEvent('destroy', null));
        });
        return Promise.resolve();
    };
    DataProcesser.prototype.addEventListener = function (eventName, listener) {
        this.emitor.addListener(eventName, listener);
    };
    DataProcesser.prototype.removeEventListener = function (eventName, listener) {
        this.emitor.removeListener(eventName, listener);
    };
    return DataProcesser;
}());
export { DataProcesser };
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