A system and method regulate the transmission of media data. In accordance with one embodiment of the invention, a header portion of a media file is encoded to include an access code. The access code corresponds to one or more permitted methods by which the media file may be transmitted over a network. In one embodiment, a user operates a web browser to access a web page including a hyperlink which references the media file and specifies a desired type of transmission. Desired types of transmission include, for example, streaming transmission and faster than real time reliable download. When the hyperlink is activated, a web server sends a URL referencing the media file to the web browser. The web browser passes the URL to the media player. The media player requests the media file from a media server. The media server transmits the header of the media file, and the media player extracts the access code to determine whether the media file may be transmitted according to the desired type of transmission. If so, the media server transmits the media file using the desired type of transmission, and the media player renders the media data into video, sound or image signals. If the media player receives the media data using a type of transmission that permits storing the media data locally, the media player may transfer the media data to a portable media player.