Matsushita This document specifies an RTP payload format for the transmission of 3GPP (3rd Generation Partnership Project) timed text. 3GPP timed text is time-lined decorated text media format based on the ISO (International Standardisation Organisation) Base Media File Format. As of today, 3GPP timed text contents can be downloaded via HTTP and synchronised with audio/video contents. There is however no available mechanism for streaming 3GPP timed text. In the following sections the problems of streaming timed text are addressed and a payload format for streaming 3GPP timed text over RTP is specified.