Web/API/MediaTrackConstraints/deviceId

The MediaTrackConstraints dictionary's deviceId property is a ConstrainDOMString describing the requested or mandatory constraints placed upon the value of the deviceId constrainable property.

If needed, you can determine whether or not this constraint is supported by checking the value of MediaTrackSupportedConstraints.deviceId as returned by a call to MediaDevices.getSupportedConstraints(). However, typically this is unnecessary since browsers will simply ignore any constraints they're unfamiliar with.

Because RTP doesn't include this information, tracks associated with a WebRTC RTCPeerConnection will never include this property.

Syntax

var constraintsObject = { deviceId: constraint };

constraintsObject.deviceId = constraint;

Value

An object based on ConstrainDOMString specifying one or more acceptable, ideal, and/or exact (mandatory) device IDs which are acceptable as the source of media content.

Device IDs are unique for a given origin, and are guaranteed to be the same across browsing sessions on the same origin. However, the value of the deviceId is determined by the source of the track's content, and there's no particular format mandated by the specification (although some kind of GUID is recommended). That means that a given track will only return one value for the deviceId when you call getCapabilities().

Because of this, there's no use for the device ID when calling MediaStreamTrack.applyConstraints(), since there is only one possible value; however, you can record a deviceId and use it to ensure that you get the same source for multiple calls to getUserMedia().

An exception to the rule that device IDs are the same across browsing sessions: private browsing mode will use a different ID, and will change it each browsing session.

Example

See Example: Constraint exerciser in Capabilities, constraints, and settings for an example.

Specifications

Specification	Status	Comment
Media Capture and StreamsThe definition of 'deviceId' in that specification.	Candidate Recommendation	Initial specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`deviceId`	Chrome Full support 59	Edge Full support ≤79	Firefox Full support 36 Notes' Full support 36 Notes' Notes' Prior to Firefox 69, Firefox only supported `deviceId` in constraints passed into `getUserMedia()`.	IE No support No	Opera Full support Yes	Safari ?	WebView Android Full support 59	Chrome Android Full support 59	Firefox Android Full support 36 Notes' Full support 36 Notes' Notes' Firefox for Android only supports `deviceId` when used in constraints passed into `getUserMedia()`.	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 7.0

Legend

Full support: Full support
No support: No support
Compatibility unknown: Compatibility unknown
See implementation notes.': See implementation notes.