The higher attribute specifies the behavior of the media elements within a priorityClass element when they are interrupted by media elements of a higher priorityClass.
You can assign the following values to the higher attribute.
||Specifies that the media element pauses when its playback is interrupted by a media element that has a higher priority. The interrupted media element resumes playback when the higher-priority element ends. This is the default value for the higher attribute.|
||Specifies that the media element stops when playback is interrupted by a media element in that has a higher priority. The interrupted element does not resume playback.|
Priority is determined by the order in which priorityClass elements are declared in an excl element. The first priorityClass element in an excl element has the highest priority, and the last priorityClass element has the lowest priority.
A media element will be interrupted if the begin attribute of another media element is set to start while the first is still playing. You can also interrupt a media element by initiating a server event that triggers the start of another element. Server events can be initiated by using a script command that is embedded in a stream from an encoder or by using the server object model. For more information about server events, see the Windows Media Services Software Development Kit (SDK). For more information about stream switching using script commands, see priorityClass element.
The following example uses three priorityClass elements, each containing one media element. The priorityClass element P3 begins playback with the media element named Broadcast1, which is a broadcast stream from an encoder.
At 45 seconds, the media element named Ad1 interrupts
Broadcast1 because it is the child of a higher priorityClass
element called P2. Because the higher attribute of P3 is set
pause, Broadcast1 pauses when Ad1 interrupts and
resumes playback when Ad1 ends.
After Ad1 plays for 10 seconds, the media element named
Wait1 interrupts because it is the child of the higher
priorityClass element called P1. Because P2 has a
higher attribute value of
stop, Ad1 will not
continue playing when Wait1 finishes. As soon as Wait1 is complete,
Broadcast1 resumes playback.
<?wsx version="1.0"?> <smil> <excl> <priorityClass id="P1"> <media id="Wait1" src="Bumper1.wma" begin="Ad1.begin+10s"/> </priorityClass> <priorityClass id="P2" higher="stop"> <media id="Ad1" src="Ad1.wma" begin="45s"/> </priorityClass> <priorityClass id="P3" higher="pause"> <media id="Broadcast1" src="http://encoder:1000" begin="0s"/> </priorityClass> </excl> </smil>
The higher attribute can be specified for the following playlist element: