MediaDevices

The MediaDevices interface provides access to connected media input devices like cameras and microphones, as well as screensharing.

Properties

Inherits properties from its parent EventTarget.

Event handlers

MediaDevices.ondevicechange

Returns the event handler for the devicechange event type.

Methods

Inherits methods from its parent EventTarget.

EventTarget.addEventListener()

Registers an event handler to a specific event type.

MediaDevices.enumerateDevices()

Obtains an array of information about the media input and output devices available on the system.

MediaDevices.getSupportedConstraints()

Returns an object conforming to MediaTrackSupportedConstraints indicating which constrainable properties are supported on the MediaStreamTrack interface. See "Capabilities and constraints" in MediaStream API to learn more about constraints and how to use them.

MediaDevices.getUserMedia()

With the user's permission through a prompt, turns on a camera or screensharing and/or a microphone on the system and provides a MediaStream containing a video track and/or an audio track with the input.

EventTarget.removeEventListener()

Removes an event listener.

Example

'use strict';

// Put variables in global scope to make them available to the browser console.
var video = document.querySelector('video');
var constraints = window.constraints = {
  audio: false,
  video: true
};
var errorElement = document.querySelector('#errorMsg');

navigator.mediaDevices.getUserMedia(constraints)
.then(function(stream) {
  var videoTracks = stream.getVideoTracks();
  console.log('Got stream with constraints:', constraints);
  console.log('Using video device: ' + videoTracks[0].label);
  stream.onended = function() {
    console.log('Stream ended');
  };
  window.stream = stream; // make variable available to browser console
  video.srcObject = stream;
})
.catch(function(error) {
  if (error.name === 'ConstraintNotSatisfiedError') {
    errorMsg('The resolution ' + constraints.video.width.exact + 'x' +
        constraints.video.width.exact + ' px is not supported by your device.');
  } else if (error.name === 'PermissionDeniedError') {
    errorMsg('Permissions have not been granted to use your camera and ' +
      'microphone, you need to allow the page access to your devices in ' +
      'order for the demo to work.');
  }
  errorMsg('getUserMedia error: ' + error.name, error);
});

function errorMsg(msg, error) {
  errorElement.innerHTML += '<p>' + msg + '</p>';
  if (typeof error !== 'undefined') {
    console.error(error);
  }
}

Specifications

Browser compatibility

See also

• WebRTC - the introductory page to the API
• Navigator.getUserMedia()