The Session object dispatches a streamPropertyChanged event in the following circumstances:

A stream has started or stopped publishing audio or video (see Publisher.publishAudio() and Publisher.publishVideo()). This change results from a call to the publishAudio() or publishVideo() methods of the Publish object. 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.
The videoDimensions property of the Stream object has changed (see Stream.videoDimensions).
The videoType property of the Stream object has changed. This can happen in a stream published by a mobile device. (See Stream.videoType.)

Name	Type	Description
`changedProperty`	String	The property of the stream that changed. This value is either `"hasAudio"`, `"hasVideo"`, or `"videoDimensions"`.
`newValue`	Object	The new value of the property (after the change).
`oldValue`	Object	The old value of the property (before the change).
`stream`	Stream	The Stream object for which a property has changed.

See:

Name	Description
`isDefaultPrevented() → {Boolean}`	Whether the default event behavior has been prevented via a call to `preventDefault()` (`true`) or not (`false`).
`preventDefault()`	Prevents the default behavior associated with the event from taking place.

Whether the default event behavior has been prevented via a call to preventDefault() (true) or not (false). See preventDefault().

Prevents the default behavior associated with the event from taking place.

To see whether an event has a default behavior, check the cancelable property of the event object.

Call the preventDefault() method in the callback function for the event.

The following events have default behaviors:

Class: StreamPropertyChangedEvent