Record audio from getUserMedia to either WAV or MP3 blobs.

var timeStarted = null,
    timeEnded   = null,
    worker      = new Worker("/path/to/mp3_worker.js"),
    config      = {
      channels: 2,
      bitrate: 96
    };

var stream = navigator.getUserMedia({audio: true, video: false}, function(stream) {
  var recorder = new UserMediaRecorder(stream, worker);

  var recording = recorder.startRecording(config);
  var timeStarted = new Date().getTime();

  // Sometime later...
  recorder.stopRecording(recording, function(blob) {
    var timeEnded = new Date().getTime();
    window.open(URL.createObjectURL(blob));
    console.log("Length: " + timeEnded - timeStarted);
  });
});

Creates a recorder that records audio from stream. Note that each UserMediaRecorder instance can only record once. Attempting to call startRecording a second time will cause an exception to be thrown.

workerUrl should be the path or URL to an encoder web worker (shipped with this library). You may use either mp3_worker.js (for recording MP3s) or wav_worker.js (for recording WAV files). If using the MP3 worker, libmp3lame.js must be available in the same directory as the worker.

• stream - the user media stream to record
• worker - a Web Worker to use for audio processing; the worker used determines the type of the blob (e.g. audio/wav or audio/mpeg)

Starts recording the stream, using the given configuration for the recording.

• config - an optional object of key/value pairs:
  • config.mono - whether or not to record mono audio - defaults to false
  • config.bufferSize - the buffer size to use for createScriptProcessor - defaults to 4096
  • config.bitrate - the bit rate, only used by the MP3 encoder - defaults to 128

Stops recording the stream and calls the callback with the recording.

• callback(blob) - a callback that the recorder will call when the audio data is ready. blob is a Blob containing the audio data

• WAV encoding doesn't work correctly if config.mono is set to false
• MP3 recordings that use two channels use only the microphone's left channel for both output channels

To build the redistributable browser build, run npm run build.