Detecting whether a stream has audio or video

By default, a Subscriber object plays back both audio and video (if they are available). You can check if a stream has audio or video (if the publisher of the stream is streaming audio or video) by checking the hasAudio and hasVideo properties of the Stream object:

For example, when you subscribe to a stream, you may want to adjust the user interface based on whether the stream has audio or video. For example, you may want to indicate to the user whether a stream has audio or not; or you may not want to hide a subscriber if a stream does not have video.

Detecting when a stream adds or removes audio or video

The Session object dispatches a streamPropertyChanged event when a stream toggles audio or video on or off. The streamPropertyChanged event is defined by the StreamPropertyChangedEvent class. The event object has a changedProperty property (identifying the Stream property that changed) and a newValue property (the new value of the Stream property). For example, the following code listens for changes in an audio and video in a Stream:

Note that a subscriber's video can be disabled or enabled for reasons other than the publisher disabling or enabling it. A Subscriber object dispatches videoDisabled and videoEnabled events in all conditions that cause the subscriber's stream to be disabled or enabled. For details, see the documentation for the Subscriber videoDisabled and [Subscriber videoEnabled]https://vonage.github.io/video-docs/video-js-reference/latest/Subscriber.html#event:videoEnabled) events.