Navigator.getUserMedia()

The Navigator.getUserMedia() method prompts the user for permission to use 0 or 1 video and 0 or 1 audio input device such as a camera, a shared screen, or a microphone. If the user provides permission, then the successCallback is invoked with the resulting MediaStream object as its argument. If the user denies permission or media is not available, then the errorCallback is called with PermissionDeniedError or NotFoundError respectively. Note that it is possible for neither completion callback to be called, as the user is not required to make a choice.

Syntax

navigator.getUserMedia(constraints, successCallback, errorCallback);

Parameters

constraints

A MediaStreamConstaints 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.

successCallback

When the call succeeds, the function specified in the successCallback is invoked with the MediaStream object that contains the media stream. You may assign that object to the appropriate element and work with it, as shown in the following example:

function(stream) {
   var video = document.querySelector('video');
   video.src = window.URL.createObjectURL(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. The error codes are described as follows:

Error	Description
PermissionDeniedError	Permission to use a media device was denied by the user or the system.
NotFoundError	No media tracks of the type specified were found that satisfy the constraints specified.

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.src = window.URL.createObjectURL(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.