RTP Payload Format for Flexible Forward Error Correction (FEC)
draft-ietf-payload-flexible-fec-scheme-03
PAYLOAD V. Singh
Internet-Draft callstats.io
Intended status: Standards Track A. Begen
Expires: May 4, 2017 Networked Media
M. Zanaty
Cisco
G. Mandyam
Qualcomm Innovation Center
October 31, 2016
RTP Payload Format for Flexible Forward Error Correction (FEC)
draft-ietf-payload-flexible-fec-scheme-03
Abstract
This document defines new RTP payload formats for the Forward Error
Correction (FEC) packets that are generated by the non-interleaved
and interleaved parity codes from a source media encapsulated in RTP.
These parity codes are systematic codes, where a number of repair
symbols are generated from a set of source symbols. These repair
symbols are sent in a repair flow separate from the source flow that
carries the source symbols. The non-interleaved and interleaved
parity codes which are defined in this specification offer a good
protection against random and bursty packet losses, respectively, at
a cost of decent complexity. Moreover, alternate FEC codes may be
used with the payload formats presented. The RTP payload formats
that are defined in this document address the scalability issues
experienced with the earlier specifications including RFC 2733, RFC
5109 and SMPTE 2022-1, and offer several improvements. Due to these
changes, the new payload formats are not backward compatible with the
earlier specifications, but endpoints that do not implement the
scheme can still work by simply ignoring the FEC packets.
Status of This Memo
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Singh, et al. Expires May 4, 2017 [Page 1]
Internet-Draft RTP Payload Format for Parity FEC October 2016
This Internet-Draft will expire on May 4, 2017.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Parity Codes . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1. Use Cases for 1-D FEC Protection . . . . . . . . . . 6
1.1.2. Use Cases for 2-D Parity FEC Protection . . . . . . . 8
1.1.3. Overhead Computation . . . . . . . . . . . . . . . . 9
2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 9
3. Definitions and Notations . . . . . . . . . . . . . . . . . . 10
3.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 10
3.2. Notations . . . . . . . . . . . . . . . . . . . . . . . . 10
4. Packet Formats . . . . . . . . . . . . . . . . . . . . . . . 10
4.1. Source Packets . . . . . . . . . . . . . . . . . . . . . 10
4.2. Repair Packets . . . . . . . . . . . . . . . . . . . . . 10
5. Payload Format Parameters . . . . . . . . . . . . . . . . . . 16
5.1. Media Type Registration - Parity Codes . . . . . . . . . 16
5.1.1. Registration of audio/flexfec . . . . . . . . . . . . 17
5.1.2. Registration of video/flexfec . . . . . . . . . . . . 18
5.1.3. Registration of text/flexfec . . . . . . . . . . . . 19
5.1.4. Registration of application/flexfec . . . . . . . . . 21
5.2. Mapping to SDP Parameters . . . . . . . . . . . . . . . . 22
5.2.1. Offer-Answer Model Considerations . . . . . . . . . . 23
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