Provided is a method for transmitting packet-based media data having a header in which an overhead is minimized. A method for media data transmission may comprise the steps of: encapsulating media data to allow a media fragment unit (MFU) header and an M-unit header to share one format; allowing an MMT payload format to include a header field for an operation which is not supported by an RTP header, and transferring the encapsulated media data from a specific entity to another entity; and controlling the transfer of the media data. Therefore, a transmission overhead is minimized, so that it is possible to efficiently transmit media data.