{"json_modified": "2016-10-20T16:18:42.334297", "uuid": "19d5d550-b0ad-427f-ac73-5968a6d9e4e3", "title": "MediaTrackSettings.deviceId", "url": "/en-US/docs/Web/API/MediaTrackSettings/deviceId", "tags": ["API", "deviceId", "WebRTC", "Reference", "Property", "Media Streams API", "Settings", "MediaTrackSettings", "Media Capture and Streams API", "Media"], "translations": [], "modified": "2016-10-20T16:18:42", "label": "MediaTrackSettings.deviceId", "localization_tags": [], "locale": "en-US", "id": 196789, "last_edit": "2016-10-20T16:18:34", "summary": "The <a href=\"/en-US/docs/Web/API/MediaTrackSettings\" title=\"The MediaTrackSettings dictionary is used to return the current values configured for each of a MediaStreamTrack's settings. These values will adhere as closely as possible to any constraints previously described using a MediaTrackConstraints object and set using applyConstraints(), and will adhere to the default constraints for any properties whose constraints haven't been changed, or whose customized constraints couldn't be matched.\"><code>MediaTrackSettings</code></a> dictionary's <code><strong>deviceId</strong></code> property is a <a href=\"/en-US/docs/Web/API/DOMString\" title=\"DOMString is a UTF-16 String. As JavaScript already uses such strings, DOMString is mapped directly to a String.\"><code>DOMString</code></a> which uniquely identifies the source for the corresponding <a href=\"/en-US/docs/Web/API/MediaStreamTrack\" title=\"The MediaStreamTrack interface represents&#xA0;a single media track within a stream; typically, these are audio or video tracks, but other track types may exist as well.\"><code>MediaStreamTrack</code></a> for the origin corresponding to the browsing session. This lets you determine what value was selected to comply with your specified constraints for this property's value as described in the <a href=\"/en-US/docs/Web/API/MediaTrackConstraints/deviceId\" title=\"The MediaTrackConstraints dictionary's deviceId property is a ConstrainDOMString describing the requested or mandatory constraints placed upon the value of the deviceId constrainable property.\"><code>MediaTrackConstraints.deviceId</code></a> property you provided when calling either <a href=\"/en-US/docs/Web/API/MediaDevices/getUserMedia\" title=\"The MediaDevices.getUserMedia() method prompts the user for permission to use one video and/or one audio input device such as a camera or screensharing and/or a microphone. If the user provides permission, then the returned Promise is resolved with the resulting MediaStream object. If the user denies permission, or media is not available, then the promise is rejected with PermissionDeniedError or NotFoundError respectively. Note that it is possible for the returned promise to neither resolve nor reject, as the user is not required to make a choice.\"><code>getUserMedia()</code></a>.", "sections": [{"id": "Quick_Links", "title": null}, {"id": "Syntax", "title": "Syntax"}, {"id": "Value", "title": "Value"}, {"id": "Example", "title": "Example"}, {"id": "Specifications", "title": "Specifications"}, {"id": "Browser_compatibility", "title": "Browser compatibility"}, {"id": "See_also", "title": "See also"}], "slug": "Web/API/MediaTrackSettings/deviceId", "review_tags": []}