Gets the natural duration of the media.
value = object.NaturalDuration
The natural duration of the media.
This property is read-only. The default value is Automatic, which is the value held if you query this property before the MediaOpened event.
The property value is not available until the MediaOpened event has been raised.
If the opened media is live streaming media, NaturalDuration is null.
When you have the Duration value, you can get its Seconds property value.