Apparatus and method for transmitting multimedia data in a broadcast system

An apparatus for transmitting media data in a broadcasting system, the apparatus comprising:

• a controller configured to control to:
• generate a packet header and a packet payload based on a data unit of media data;
• and
• a transmitter configured to transmit the packet payload,
• wherein the packet payload comprises:
• the data unit,
• a fragmentation indicator indicating information about fragmentation of the data unit in the packet payload,
• length information on the packet payload,
• aggregation information on whether the data unit is aggregated with another data unit, and
• sequence number information on the data unit,
• wherein, if the data unit is fragmented, the packet payload comprises a fragmented data unit and the fragmentation indicator indicates information which part of the data unit is included in the packet payload, and
• wherein, if the data unit is not fragmented, the packet payload comprises at least one complete data unit and the fragmentation indicator indicates that the packet payload includes the at least one complete data unit.