Ogg Encapsulation for the Opus Audio Codec
RFC 7845

Document Type RFC - Proposed Standard (April 2016; No errata)
Updates RFC 5334
Last updated 2016-04-29
Replaces draft-terriberry-oggopus
Stream IETF
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Reviews
Stream WG state Submitted to IESG for Publication Jan 2013
Document shepherd Mo Zanaty
Shepherd write-up Show (last changed 2015-11-25)
IESG IESG state RFC 7845 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Ben Campbell
Send notices to "Mo Zanaty" <mzanaty@cisco.com>
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack
Internet Engineering Task Force (IETF)                     T. Terriberry
Request for Comments: 7845                           Mozilla Corporation
Updates: 5334                                                     R. Lee
Category: Standards Track                                    Voicetronix
ISSN: 2070-1721                                                 R. Giles
                                                     Mozilla Corporation
                                                              April 2016

               Ogg Encapsulation for the Opus Audio Codec

Abstract

   This document defines the Ogg encapsulation for the Opus interactive
   speech and audio codec.  This allows data encoded in the Opus format
   to be stored in an Ogg logical bitstream.

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/rfc7845.

Copyright Notice

   Copyright (c) 2016 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
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Terriberry, et al.           Standards Track                    [Page 1]
RFC 7845                        Ogg Opus                      April 2016

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Packet Organization . . . . . . . . . . . . . . . . . . . . .   4
   4.  Granule Position  . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  Repairing Gaps in Real-Time Streams . . . . . . . . . . .   7
     4.2.  Pre-skip  . . . . . . . . . . . . . . . . . . . . . . . .   9
     4.3.  PCM Sample Position . . . . . . . . . . . . . . . . . . .   9
     4.4.  End Trimming  . . . . . . . . . . . . . . . . . . . . . .  10
     4.5.  Restrictions on the Initial Granule Position  . . . . . .  10
     4.6.  Seeking and Pre-roll  . . . . . . . . . . . . . . . . . .  11
   5.  Header Packets  . . . . . . . . . . . . . . . . . . . . . . .  12
     5.1.  Identification Header . . . . . . . . . . . . . . . . . .  12
       5.1.1.  Channel Mapping . . . . . . . . . . . . . . . . . . .  16
     5.2.  Comment Header  . . . . . . . . . . . . . . . . . . . . .  22
       5.2.1.  Tag Definitions . . . . . . . . . . . . . . . . . . .  25
   6.  Packet Size Limits  . . . . . . . . . . . . . . . . . . . . .  26
   7.  Encoder Guidelines  . . . . . . . . . . . . . . . . . . . . .  27
     7.1.  LPC Extrapolation . . . . . . . . . . . . . . . . . . . .  28
     7.2.  Continuous Chaining . . . . . . . . . . . . . . . . . . .  28
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  29
   9.  Content Type  . . . . . . . . . . . . . . . . . . . . . . . .  30
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  31
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  32
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  32
     11.2.  Informative References . . . . . . . . . . . . . . . . .  33
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  34
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  35

1.  Introduction

   The IETF Opus codec is a low-latency audio codec optimized for both
   voice and general-purpose audio.  See [RFC6716] for technical
   details.  This document defines the encapsulation of Opus in a
   continuous, logical Ogg bitstream [RFC3533].  Ogg encapsulation
   provides Opus with a long-term storage format supporting all of the
   essential features, including metadata, fast and accurate seeking,
   corruption detection, recapture after errors, low overhead, and the
   ability to multiplex Opus with other codecs (including video) with
   minimal buffering.  It also provides a live streamable format capable
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