MediaRecorder.mimeType

The MediaRecorder.mimeType read-only property returns the MIME type that is being used as the recording container when it was created. This is the file format of the file that would result from writing all of the recorded data to disk. Keep in mind, of course, that the file format and the codecs associated with the individual tracks are different things entirely; writing tracks that work just fine in a WebM video into an MP4 wrapper may not result in a file that plays everywhere you want  it to.

Syntax

var mimeType = MediaRecorder.mimeType

Value

The MIME type being used as the container format for the recorded media, in DOMString form.

Example

...

navigator.getUserMedia = (navigator.getUserMedia ||
                          navigator.mozGetUserMedia ||
                          navigator.msGetUserMedia ||
                          navigator.webkitGetUserMedia);


if (navigator.getUserMedia) {
  console.log('getUserMedia supported.');

  var constraints = { audio: true, video: true };
  var chunks = [];

  var onSuccess = function(stream) {
    var options = {
      audioBitsPerSecond : 128000,
      videoBitsPerSecond : 2500000,
      mimeType : 'video/mp4'
    }
    var mediaRecorder = new MediaRecorder(stream,options);
    m = mediaRecorder;

    m.mimeType; // would return 'video/mp4'

...

Specifications

Browser compatibility

[1] The intial Firefox OS implementation only supported audio recording.

[2] To try this feature on Chrome, enable Experimental Web Platform features from chrome://flags . Currently only video is supported, not audio.

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