RTP Payload Format for 1-D Interleaved Parity Forward Error Correction (FEC)
RFC 6015

Internet Engineering Task Force (IETF)                          A. Begen
Request for Comments: 6015                                         Cisco
Category: Standards Track                                   October 2010
ISSN: 2070-1721

             RTP Payload Format for 1-D Interleaved Parity
                     Forward Error Correction (FEC)

Abstract

   This document defines a new RTP payload format for the Forward Error
   Correction (FEC) that is generated by the 1-D interleaved parity code
   from a source media encapsulated in RTP.  The 1-D interleaved parity
   code is a systematic code, where a number of repair symbols are
   generated from a set of source symbols and sent in a repair flow
   separate from the source flow that carries the source symbols.  The
   1-D interleaved parity code offers a good protection against bursty
   packet losses at a cost of reasonable complexity.  The new payload
   format defined in this document should only be used (with some
   exceptions) as a part of the Digital Video Broadcasting-IPTV (DVB-
   IPTV) Application-layer FEC specification.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6015.

Begen                        Standards Track                    [Page 1]
RFC 6015         RTP Payload Format for Interleaved FEC     October 2010

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   described in the Simplified BSD License.

Begen                        Standards Track                    [Page 2]
RFC 6015         RTP Payload Format for Interleaved FEC     October 2010

Table of Contents

   1. Introduction ....................................................4
      1.1. Use Cases ..................................................6
      1.2. Overhead Computation .......................................8
      1.3. Relation to Existing Specifications ........................8
           1.3.1. RFCs 2733 and 3009 ..................................8
           1.3.2. SMPTE 2022-1 ........................................8
           1.3.3. ETSI TS 102 034 .....................................9
      1.4. Scope of the Payload Format ...............................10
   2. Requirements Notation ..........................................10
   3. Definitions, Notations, and Abbreviations ......................10
      3.1. Definitions ...............................................10
      3.2. Notations .................................................11
   4. Packet Formats .................................................11
      4.1. Source Packets ............................................11
      4.2. Repair Packets ............................................11
   5. Payload Format Parameters ......................................15
      5.1. Media Type Registration ...................................15
           5.1.1. Registration of audio/1d-interleaved-parityfec .....15
           5.1.2. Registration of video/1d-interleaved-parityfec .....16
           5.1.3. Registration of text/1d-interleaved-parityfec ......18
           5.1.4. Registration of
                  application/1d-interleaved-parityfec ...............19
      5.2. Mapping to SDP Parameters .................................20
           5.2.1. Offer-Answer Model Considerations ..................21
           5.2.2. Declarative Considerations .........................22
   6. Protection and Recovery Procedures .............................22
      6.1. Overview ..................................................22
      6.2. Repair Packet Construction ................................22
      6.3. Source Packet Reconstruction ..............................24
           6.3.1. Associating the Source and Repair Packets ..........25