MediaRecorder

« MediaRecorder

Properties

MediaRecorder.state Read only

Returns the current state of the MediaRecorder object (inactive, recording, or paused.)

MediaRecorder.stream Read only

Returns the stream that was passed into the constructor when the MediaRecorder was created.

Methods

MediaRecorder.pause()

Pauses the recording of media.

MediaRecorder.requestData()

Requests a Blob containing the saved data received thus far (or since the last time requestData() was called. After calling this method, recording continues, but in a new Blob.

MediaRecorder.resume()

Resumes recording of media after having been paused.

MediaRecorder.start()

Begins recording media; this method can optionally be passed a timeslice argument with a value in milliseconds. If this is specified, the media will be captured in separate chunks of that duration, rather than the default behavior of recording the media in a single large chunk.

MediaRecorder.stop()

Stops recording, at which point a dataavailable event containing the final Blob of saved data is fired. No more recording occurs.

Event Handlers

MediaRecorder.ondataavailable

Called to handle the dataavailable event, which can be used to grab the recorded media (which is made available as a Blob object in the event's data attribute.)

MediaRecorder.onerror

Called to handle the DOMError event, including reporting errors that arise with media recording. These are fatal errors that stop recording.

MediaRecorder.onpause

Called to handle the pause event, which occurs when media recording is paused.

MediaRecorder.onresume

Called to handle the resume event, which occurs when media recording resumes after being paused.

MediaRecorder.onstart

Called to handle the start event, which occurs when media recording starts.

MediaRecorder.onstop

Called to handle the stop event, which occurs when media recording ends, either when the MediaStream ends — or after the MediaRecorder.stop() method is called.

MediaRecorder.onwarning

Called to handle the warning event, which occurs when non-fatal errors occur that do not stop the recording.

Example

if (navigator.getUserMedia) {
   console.log('getUserMedia supported.');
   navigator.getUserMedia (
      // constraints - only audio needed for this app
      {
         audio: true
      },

      // Success callback
      function(stream) {
           var mediaRecorder = new MediaRecorder(stream);

           record.onclick = function() {
               mediaRecorder.start();
               console.log("recorder started");
           }

           stop.onclick = function() {
               mediaRecorder.stop();
               console.log("recorder stopped");
           }

           mediaRecorder.ondataavailable = function(e) {
             console.log("data available after MediaRecorder.stop() called.");

             var audio = document.createElement('audio');
             audio.setAttribute('controls', '');
             var audioURL = window.URL.createObjectURL(e.data);
             audio.src = audioURL;
           }
      },

      // Error callback
      function(err) {
         console.log('The following gUM error occured: ' + err);
      }
   );
} else {
   console.log('getUserMedia not supported on your browser!');
}

Browser compatibility

Specifications

See also

• Using the MediaRecorder API
• Web Dictaphone: MediaRecorder + getUserMedia + Web Audio API visualization demo, by Chris Mills (source on Github.)
• simpl.info MediaStream Recording demo, by Sam Dutton.
• Navigator.getUserMedia