1. A multimedia middleware apparatus of a terminal for supporting a multimedia application, the apparatus comprising: a receiver for receiving metadata comprising middleware application programming interface (API) information as structural information of a multimedia middleware service to run a multimedia application; and a processor for parsing the metadata, identifying a service implementation code for the multimedia middleware service from the received metadata, acquiring the service implementation code, determining whether the metadata and the service implementation code are related to at least one of a standard service and a non-standard service, and according to the determination result, applying the acquired service implementation code to change the multimedia application based on the acquired service implementation code and the metadata, wherein the processor is further configured to verify validity by comparing the service implementation code with associated metadata when the service implementation code is related to the standard service and to apply a valid service implementation code to an associated multimedia middleware service.