Navigator.getUserMedia()

The Navigator.getUserMedia() method prompts the user for permission to use up to one video input device (such as a camera or shared screen) and up to one audio input device (such as a microphone). If permission is granted, a MediaStream whose video and/or audio tracks come from those devices is delivered to the specified success callback. If permission is denied, no compatible input devices exist, or any other error condition occurs, the error callback is executed with a MediaStreamError object describing what went wrong. If the user instead doesn't make a choice at all, neither callback is executed.

Syntax

navigator.getUserMedia(constraints, successCallback, errorCallback);

Parameters

constraints

A MediaStreamConstraints object specifying the types of media to request, along with any requirements for each type. For details, see the constraints section under the modern MediaDevices.getUserMedia() method, as well as the article Capabilities, constraints, and settings.

successCallback

A function which is invoked when the request for media access is approved. The function is called with one parameter: the MediaStream object that contains the media stream. Your callback can then assign the stream to the desired object (such as an <audio> or <video> element), as shown in the following example:

function(stream) {
   var video = document.querySelector('video');
   video.srcObject = stream;
   video.onloadedmetadata = function(e) {
      // Do something with the video here.
   };
}

errorCallback

When the call fails, the function specified in the errorCallback is invokedwith a MediaStreamError object as its sole argument; this object is is modeled on DOMException. See {anch("Errors")}} below for a list of the errors which can occur.

Return value

undefined.

Errors

Examples

Width and height

Here's an example of using getUserMedia(), including code to cope with various browsers' prefixes. Note that this is the deprecated way of doing it: See the Examples section under the MediaDevices.getUserMedia() for modern examples.

navigator.getUserMedia = navigator.getUserMedia ||
                         navigator.webkitGetUserMedia ||
                         navigator.mozGetUserMedia;
if (navigator.getUserMedia) {
   navigator.getUserMedia({ audio: true, video: { width: 1280, height: 720 } },
      function(stream) {
         var video = document.querySelector('video');
         video.srcObject = stream;
         video.onloadedmetadata = function(e) {
           video.play();
         };
      },
      function(err) {
         console.log("The following error occurred: " + err.name);
      }
   );
} else {
   console.log("getUserMedia not supported");
}

Permissions

To use getUserMedia() in an installable app (for example, a Firefox OS app), you need to specify one or both of the following fields inside your manifest file:

"permissions": {
  "audio-capture": {
    "description": "Required to capture audio using getUserMedia()"
  },
  "video-capture": {
    "description": "Required to capture video using getUserMedia()"
  }
}

See permission: audio-capture and permission: video-capture for more information.

Specifications

Browser compatibility

[1] Later versions of Chrome support unprefixed MediaDevices.getUserMedia(), that replaced this deprecated method.

[2] Chrome and Opera still use an outdated constraint syntax, but the syntax described here is available through the adapter.js polyfill.

[3] The constraint syntax described here is available as of Firefox 38. Earlier versions (32-37) used an outdated constraint syntax, but the syntax described here is available there through the adapter.js polyfill.

[4] In Firefox OS 1.2 only audio was supported, 1.4 added support for video.

See also

• MediaDevices.getUserMedia() that replaces this deprecated method.
• WebRTC - the introductory page to the API
• MediaStream API - the API for the media stream objects
• Taking webcam photos - a tutorial on using getUserMedia() for taking photos rather than video.