Raptor FEC Schemes for FECFRAME
Digital Fountain
This document describes Fully-Specified Forward Error Correction (FEC) Schemes for the Raptor code and its application to reliable delivery of media streams in the context of FEC Framework. The Raptor code is a systematic code, where a number of repair symbols are generated from a set of source symbols and sent in one or more repair flows in addition to the source symbols that are sent to the receiver(s) within a source flow. The Raptor code offers a close to optimal protection against arbitrary packet losses at a low computational complexity. Two FEC Schemes are defined, one for protection of arbitrary packet flows and another for protection of a single flow that already contains a sequence number. Repair data may be sent over arbitrary datagram transport (e.g. UDP) or using RTP. An RTP Payload Type is defined for this latter case.