javascript - Web Audio Api - Download edited MP3 -

i'm editing mp3 file multiple effects so

var mainverse = document.getelementbyid('audio1');  var s = source; source.disconnect(audioctx.destination);  (var in filters1) {  s.connect(filters1[i]);  s = filters1[i]; }  s.connect(audioctx.destination); 

the mp3 plays accordingly on web filters on it. possible create , download new mp3 file these new effects, using web audio api or writing mp3 container javascript library ? if not whats best solve on web ?

update - using offlineaudiocontext

using sample code https://developer.mozilla.org/en-us/docs/web/api/offlineaudiocontext/oncomplete

i've tried using offline node so;

var audioctx = new audiocontext(); var offlinectx = new offlineaudiocontext(2,44100*40,44100);  osource = offlinectx.createbuffersource();  function getdata() {       request = new xmlhttprequest();       request.open('get', 'song1.mp3', true);       request.responsetype = 'arraybuffer';       request.onload = function() {         var audiodata = request.response;         audioctx.decodeaudiodata(audiodata, function(buffer) {           mybuffer = buffer;           osource.buffer = mybuffer;           osource.connect(offlinectx.destination);           osource.start();           //source.loop = true;           offlinectx.startrendering().then(function(renderedbuffer) {             console.log('rendering completed successfully');             var audioctx = new (window.audiocontext || window.webkitaudiocontext)();              var song = audioctx.createbuffersource();             song.buffer = renderedbuffer;             song.connect(audioctx.destination);             song.start();             rec = new recorder(song, {                 workerpath: 'recorderjs/recorderworker.js'             });                 rec.exportwav(function(e){                 rec.clear();                 recorder.forcedownload(e, "filename.wav");             });           }).catch(function(err) {               console.log('rendering failed: ' + err);               // note: promise should reject when startrendering called second time on offlineaudiocontext           });         });       }       request.send();     }     // run getdata start process off getdata(); 

still getting recorder download empty file, i'm using song source source recorder. song plays , code recorder doesn't download it

use https://github.com/mattdiamond/recorderjs record .wav file. use https://github.com/akrennmair/libmp3lame-js encode .mp3.

there's nifty guide here, if need hand: http://audior.ec/blog/recording-mp3-using-only-html5-and-javascript-recordmp3-js/

update

try moving

rec = new recorder(song, {     workerpath: 'recorderjs/recorderworker.js' }); 

so located above call start rendering, , connect osource instead, so:

rec = new recorder(osource, {       workerpath: 'recorderjs/recorderworker.js' });  osource.connect(offlinectx.destination); osource.start(); offlinectx.startrendering().then(function(renderedbuffer) {      .....