Optional. Event handler on the sink pad. This function should return TRUE if the event was handled and should be discarded (i.e. not unref'ed). Subclasses should chain up to the parent implementation to invoke the default handler.
Optional. Event handler on the sink pad. This function should return TRUE if the event was handled and should be discarded (i.e. not unref'ed). Subclasses should chain up to the parent implementation to invoke the default handler.