1. A method of generating multimedia data, the method comprising: allocating at least one piece of image object information to each of a plurality of nodes; generating a scene tree by linking the nodes according to correlation between the image object information allocated to each node; adding an event execution level attribute to each node, wherein the event execution level attribute determines whether to execute an event by using the image object information allocated to each node; and generating multimedia data in which the added event execution level attribute is represented with a scene description language and recorded on an area of a scene descriptor.