Acquisition of DSM-CC stream events
Support in HbbTV
Available since: HbbTV 1.0 (ETSI TS 102 796 V1.1.1)
Adding and removing stream event listeners
The following additional methods on the video/broadcast object (as defined in the OIPF DAE specification [1]) shall be supported for synchronization to broadcast events as defined in clause 7.2.4.
DSM-CC StreamEvent event
interface StreamEvent : Event{ readonly attribute String name; readonly attribute String data; readonly attribute String text; readonly attribute DOMString status; } | ||
Properties | name | The name of the DSM-CC StreamEvent’s event. |
data | Data of the DSM-CC StreamEvent’s event encoded in hexadecimal. EXAMPLE: “0A10B81033” (for a payload 5 bytes long). | |
text | Text data of the DSM-CC StreamEvent’s event as a string assuming UTF-8 as the encoding for the DSM-CC StreamEvent’s event. Characters that cannot be transcoded are skipped. Application developers should be aware that in some circumstances an attacker may be able to modify the broadcast signalling from which this data is derived. Applications shall not use this data in a way that would result in it being executed by the browser. Applications should be written to be tolerant of incorrectly formatted data or values for this data which are outside the expected range without hanging up or crashing. | |
status | Equal to “trigger” when the event is dispatched in response to a trigger in the stream or “error” when an error occurred (e.g. attempting to add a listener for an event that does not exist, or when a StreamEvent object with registered listeners is removed from the carousel). Circumstances under which an event shall be dispatched with an error status include: · the StreamEvent object pointed to by targetURL is not found in the carousel or via broadband; · the StreamEvent object pointed to by targetURL does not contain the event specified by the eventName parameter; · the carousel cannot be mounted; · the elementary stream which contains the StreamEvent event descriptor is no longer being monitored (e.g. due to another monitoring request or because it disappears from the PMT). Once an error is dispatched, the listener is automatically unregistered by the terminal. |