[NEW] mp3 audio upload

.eslintignore

@@ -19,3 +19,5 @@ packages/rocketchat-theme/client/vendor/
 private/moment-locales/
 public/livechat/
 public/recorderWorker.js
+public/libmp3lame.js
+public/mp3Worker.js

packages/rocketchat-ui-message/startup/messageBoxActions.js

@@ -30,7 +30,7 @@ RocketChat.messageBox.actions.add('Create_new', 'Audio_message', {
 					{
 						file: blob,
 						type: 'audio',
-						name: `${ TAPi18n.__('Audio record') }.wav`
+						name: `${ TAPi18n.__('Audio record') }.mp3`
 					}
 				]);
 			});

packages/rocketchat-ui/client/lib/recorderjs/recorder.js

 (function(window){
 
   var WORKER_PATH = 'recorderWorker.js';
+  var encoderWorker = new Worker('mp3Worker.js');
 
   var Recorder = function(source, cfg){
     var config = cfg || {};
     var bufferLen = config.bufferLen || 4096;
-    var numChannels = config.numChannels || 2;
+    var numChannels = config.numChannels || 1;
     this.context = source.context;
     this.node = (this.context.createScriptProcessor ||
                  this.context.createJavaScriptNode).call(this.context,
@@ -70,7 +71,63 @@
 
     worker.onmessage = function(e){
       var blob = e.data;
-      currCallback(blob);
+      var arrayBuffer;
+      var fileReader = new FileReader();
+
+      fileReader.onload = function(){
+        arrayBuffer = this.result;
+        var buffer = new Uint8Array(arrayBuffer),
+        data = parseWav(buffer);
+
+        encoderWorker.postMessage({ cmd: 'init', config:{
+          mode : 3,
+          channels:1,
+          samplerate: data.sampleRate,
+          bitrate: data.bitsPerSample
+        }});
+
+        encoderWorker.postMessage({ cmd: 'encode', buf: Uint8ArrayToFloat32Array(data.samples) });
+        encoderWorker.postMessage({ cmd: 'finish'});
+        encoderWorker.onmessage = function(e) {
+          if (e.data.cmd == 'data') {
+            var mp3Blob = new Blob([new Uint8Array(e.data.buf)], {type: 'audio/mp3'});
+            currCallback(mp3Blob);
+          }
+        };
+      };
+
+      fileReader.readAsArrayBuffer(blob);
+    }
+
+    function parseWav(wav) {
+      function readInt(i, bytes) {
+        var ret = 0,
+        shft = 0;
+        while (bytes) {
+          ret += wav[i] << shft;
+          shft += 8;
+          i++;
+          bytes--;
+        }
+        return ret;
+      }
+      if (readInt(20, 2) != 1) throw 'Invalid compression code, not PCM';
+      if (readInt(22, 2) != 1) throw 'Invalid number of channels, not 1';
+      return {
+        sampleRate: readInt(24, 4),
+        bitsPerSample: readInt(34, 2),
+        samples: wav.subarray(44)
+      };
+    }
+
+    function Uint8ArrayToFloat32Array(u8a){
+      var f32Buffer = new Float32Array(u8a.length);
+      for (var i = 0; i < u8a.length; i++) {
+        var value = u8a[i<<1] + (u8a[(i<<1)+1]<<8);
+        if (value >= 0x8000) value |= ~0x7FFF;
+        f32Buffer[i] = value / 0x8000;
+      }
+      return f32Buffer;
     }
 
     source.connect(this.node);
@@ -81,7 +138,7 @@
     var url = (window.URL || window.webkitURL).createObjectURL(blob);
     var link = window.document.createElement('a');
     link.href = url;
-    link.download = filename || 'output.wav';
+    link.download = filename || 'output.mp3';
     var click = document.createEvent("Event");
     click.initEvent("click", true, true);
     link.dispatchEvent(click);
@@ -89,4 +146,4 @@
 
   window.Recorder = Recorder;
 
-})(window);
\ No newline at end of file
+})(window);

public/mp3Worker.js

+importScripts('libmp3lame.js')
+var mp3codec;
+
+self.onmessage = function(e) {
+	switch (e.data.cmd) {
+	case 'init':
+		if (!e.data.config) {
+			e.data.config = { };
+		}
+		mp3codec = Lame.init();
+
+		Lame.set_mode(mp3codec, e.data.config.mode || Lame.JOINT_STEREO);
+		Lame.set_num_channels(mp3codec, e.data.config.channels || 2);
+		Lame.set_num_samples(mp3codec, e.data.config.samples || -1);
+		Lame.set_in_samplerate(mp3codec, e.data.config.samplerate || 44100);
+		Lame.set_out_samplerate(mp3codec, e.data.config.samplerate || 44100);
+		Lame.set_bitrate(mp3codec, e.data.config.bitrate || 128);
+		Lame.init_params(mp3codec);
+		break;
+	case 'encode':
+		var mp3data = Lame.encode_buffer_ieee_float(mp3codec, e.data.buf, e.data.buf);
+		self.postMessage({cmd: 'data', buf: mp3data.data});
+		break;
+	case 'finish':
+		var mp3data = Lame.encode_flush(mp3codec);
+		self.postMessage({cmd: 'end', buf: mp3data.data});
+		Lame.close(mp3codec);
+		mp3codec = null;
+		break;
+	}
+};