The metadata property of the MediaSession interface contains a MediaMetadata object providing descriptive information about the currently playing media, or null if the metadata has not been set. This metadata is provided by the browser to the device for presentation in any standard media control user interface the device might offer.
The playbackState property of the MediaSession interface indicates whether the current media session is playing or paused.
The setActionHandler() method of the MediaSession interface sets a handler for a media session action. These actions let a web app receive notifications when the user engages a device's built-in physical or onscreen media controls, such as play, stop, or seek buttons.
The setCameraActive() method of the MediaSession interface is used to indicate to the user agent whether the user's camera is considered to be active.
The setMicrophoneActive() method of the MediaSession interface is used to indicate to the user agent whether the user's microphone is considered to be currently muted.
The setPositionState() method of the MediaSession interface is used to update the current document's media playback position and speed for presentation by user's device in any kind of interface that provides details about ongoing media. This can be particularly useful if your code implements a player for type of media not directly supported by the browser.
Optionalstate: MediaPositionState
The
MediaSessioninterface of the Media Session API allows a web page to provide custom behaviors for standard media playback interactions, and to report metadata that can be sent by the user agent to the device or operating system for presentation in standardized user interface elements.MDN Reference