Raptor

This document describes Fully-Specified Forward Error Correction (FEC) Schemes for the Raptor and RaptorQ codes and their application to reliable delivery of media streams in the context of the FEC Framework. The Raptor and RaptorQ codes are systematic codes, 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 and RaptorQ codes offer close to optimal protection against arbitrary packet losses at a low computational complexity. Six FEC Schemes are defined: two for the protection of arbitrary packet flows, two that are optimized for small source blocks, and two for the 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. [STANDARDS-TRACK]

This document specifies an RTP payload format for the Forward Error Correction (FEC) repair data produced by the Raptor FEC Schemes. Raptor FEC Schemes are specified for use with the IETF FEC Framework that supports the transport of repair data over both UDP and RTP. This document specifies the payload format that is required for the use of RTP to carry Raptor repair flows. [STANDARDS-TRACK]

Annex E of the Digital Video Broadcasting - IPTV (DVB-IPTV) technical specification defines an optional Application-Layer Forward Error Correction (AL-FEC) protocol to protect the streaming media transported using RTP. The DVB-IPTV AL-FEC protocol uses two layers for FEC protection. The first (base) layer is based on the 1-D interleaved parity code. The second (enhancement) layer is based on the Raptor code. By offering a layered approach, the DVB-IPTV AL-FEC protocol offers good protection against both bursty and random packet losses at a cost of decent complexity. This document describes how one can implement the DVB-IPTV AL-FEC protocol by using the 1-D interleaved parity code and Raptor code that have already been specified in separate documents. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document describes a Fully-Specified Forward Error Correction (FEC) scheme, corresponding to FEC Encoding ID 6, for the RaptorQ FEC code and its application to reliable delivery of data objects.

RaptorQ codes are a new family of codes that provide superior flexibility, support for larger source block sizes, and better coding efficiency than Raptor codes in RFC 5053. RaptorQ is also a fountain code, i.e., as many encoding symbols as needed can be generated on the fly by the encoder from the source symbols of a source block of data. The decoder is able to recover the source block from almost any set of encoding symbols of sufficient cardinality -- in most cases, a set of cardinality equal to the number of source symbols is sufficient; in rare cases, a set of cardinality slightly more than the number of source symbols is required.

The RaptorQ code described here is a systematic code, meaning that all the source symbols are among the encoding symbols that can be generated. [STANDARDS-TRACK]

This document describes a Fully-Specified Forward Error Correction (FEC) scheme, corresponding to FEC Encoding ID 1, for the Raptor forward error correction code and its application to reliable delivery of data objects.

Raptor is a fountain code, i.e., as many encoding symbols as needed can be generated by the encoder on-the-fly from the source symbols of a source block of data. The decoder is able to recover the source block from any set of encoding symbols only slightly more in number than the number of source symbols.

The Raptor code described here is a systematic code, meaning that all the source symbols are among the encoding symbols that can be generated. [STANDARDS-TRACK]