MediaDevices
The MediaDevices
interface provides access to connected media input devices like cameras and microphones, as well as screen sharing. In essence, it lets you obtain access to any hardware source of media data.
Properties
Inherits properties from its parent interface, EventTarget
.
Methods
Inherits methods from its parent interface, EventTarget
.
enumerateDevices()
-
Obtains an array of information about the media input and output devices available on the system.
getSupportedConstraints()
-
Returns an object conforming to
MediaTrackSupportedConstraints
indicating which constrainable properties are supported on theMediaStreamTrack
interface. See Capabilities and constraints in Media Capture and Streams API (Media Stream) to learn more about constraints and how to use them. getDisplayMedia()
-
Prompts the user to select a display or portion of a display (such as a window) to capture as a
MediaStream
for sharing or recording purposes. Returns a promise that resolves to aMediaStream
. getUserMedia()
-
With the user's permission through a prompt, turns on a camera and/or a microphone on the system and provides a
MediaStream
containing a video track and/or an audio track with the input. selectAudioOutput()
-
Prompts the user to select a specific audio output device.
Events
devicechange
-
Fired when a media input or output device is attached to or removed from the user's computer.
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.onremovetrack = 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.height.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
Specification |
---|
Media Capture and Streams # mediadevices |
Browser compatibility
BCD tables only load in the browser
See also
- Media Capture and Streams API: The API this interface is part of.
- Screen Capture API: The API defining the
getDisplayMedia()
method. - WebRTC API
Navigator.mediaDevices
: Returns a reference to aMediaDevices
object that can be used to access devices.- CameraCaptureJS: HTML5 video capture and playback using
MediaDevices
and the MediaStream Recording API (source on GitHub) - OpenLang: HTML5 video language lab web application using
MediaDevices
and the MediaStream Recording API for video recording (source on GitHub)