[vorbis-dev] RTP-Vorbis MIME type Internet-Draft

Tue Jan 7 09:22:27 PST 2003

Hi all,

Please find below an I-D for the proposed registration of MIME type 
audio/rtp-vorbis. All comments most welcome.  

Barry

<p>-----------8<-------------

Network Working Group                                       Barry Short
Internet-Draft                     The Ogg Vorbis Community / OpenDrama
Expires: July 7, 2003                                   January 7, 2003

<p>                       The audio/rtp-vorbis MIME Type
                   draft-short-avt-rtp-vorbis-mime-00.txt

<p>Status of this Memo

   This document is an Internet-Draft and is in full conformance
   with all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as
   Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other
   documents at any time.  It is inappropriate to use Internet-
   Drafts as reference material or to cite them other than as
   "work in progress".

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This internet draft will expire on July 7, 2003.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [1].

<p>Copyright Notice

<p>Abstract

   This document explains the need for a MIME subtype which identifies
   a Vorbis audio payload to be used within a Realtime Transport
   Protocol (RTP) bitstream.

   This document also provides the necessary information to register
   audio/rtp-vorbis as a MIME type.

<p><p><p><p><p>Short                    Expires July 7, 2003                  [Page 1]

Internet-Draft    draft-short-avt-rtp-vorbis-mime-00.txt   January 2003

<p>1. Introduction

   The Vorbis Bitstream format [5] developed by Xiph.org is a
   compressed audio format that uses pyschoacoustic compression
   algorithms with highly optimized bit-allocation. It has been
   developed as part of a larger project which aims to present a series
   of multimedia content carrier bitstreams, which are to be freely
   available to the computing community at large. These bitstreams are
   created by software or hardware encoder-decoders (codecs).

   For file based storage, Vorbis is generally encapsulated within the
   Ogg bitstream format described in [2]. However, raw packets from the
   Vorbis codecs can be used directly with transport mechanisms that
   provide their own framing and packet-separation.

   One such mechanism is the Real-time Transport Protocol (RTP),
   described in [3]. A payload format for using Vorbis audio over RTP
   is described in [4]. This document serves to register the
   audio/rtp-vorbis MIME type, and is a companion document to [4].

<p><p>2. Registration Information:

<p>   To: ietf-types at iana.org

   Subject: Registration of MIME type audio/rtp-vorbis

   Media MIME type name: audio

   Media MIME subtype name: rtp-vorbis

   Required Parameters: none

   Optional Parameters: none

<p><p>   Encoding Considerations:

   The Vorbis audio data is always wrapped within and RTP bitstream
   when transported with this MIME type.

   Since the Vorbis data is already compressed as detailed above,
   further lossless compression MAY be unnecessary. However, RTP
   header compression MAY be used to reduce the packet size.

   See [4] for further information on RTP encoding issues.

<p><p><p><p><p>Short                    Expires July 7, 2003                  [Page 2]

Internet-Draft    draft-short-avt-rtp-vorbis-mime-00.txt   January 2003

<p>   Security Considerations:

   The Vorbis format is highly specified [5] and so cannot contain
   security violating code. It could be possible to exploit errors or
   vulnerabilities in the decoder implementation, by abusing fields
   with arbitrary code. It is the decoder's responsibility to ensure
   that untrusted code is not executed.

   Vorbis bitstreams are neither signed nor encrypted, so external
   security systems should be added to ensure authenticity or
   confidentiality where required.

   Cryptographic authentication of incoming RTP and RTCP packets is
   highly recommended. Without such protections, attackers could
   corrupt the audio bitstream, potentially damaging speakers and
   eardrums.

   Further RTP security considerations are detailed in [3].

<p>   Interoperability Consideration:

   Conformance to the specification detailed in [4] ensures no
   interoperability issues need arise.

<p>   Published Specification:

   See [4]

<p>   Applications which use this media type:

   Any application which uses the specification outlined in [4]
   will be able to decode the bitestream.

<p>   Additional Information:

   Magic Numbers: none

   File Extention: none

   Macintosh File Type Code: none

   Object Identifier(s) of OID(s): none

<p><p><p><p><p><p><p><p>Short                    Expires July 7, 2003                  [Page 3]

Internet-Draft    draft-short-avt-rtp-vorbis-mime-00.txt   January 2003

<p>   Person & Email address to contact for further information:

   For questions about this proposal contact:
   Barry Short <b.short at elec.gla.ac.uk>.

   For technical questions about Vorbis see the mailing list of the
   developer community <http://www.xiph.org/archives>

<p>   Internet Usage: COMMON

<p>   Author/Change Controller:

   This document was written by Barry Short, changes of this document
   will be handled by the author or a representative of the Vorbis
   development community.

<p>3. Security Considerations:

   Security considerations are discussed in the security considerations
   clause in section 2 of this document.

<p>4. References

   1. Key words for use in RFCs to Indicate Requirement Levels
      (RFC 2119)

   2. The Ogg encapsulation format,
      Work in Progress, draft-pfeiffer-ogg-fileformat-00.txt

   3. RTP: A Transport Protocol for Real-Time Applications, (RFC 1889)

   4. RTP Payload Format for Vorbis Encoded Audio.
      Work in Progress, draft-kerr-avt-vorbis-rtp-00.txt

   5. libvorbis: Available from Xiph website, http://www.xiph.org

<p>5. Author's address
   Barry Short
   Centre for Music Technology
   University of Glasgow
   Glasgow
   UK
   G12 8LT
   Phone: +44 141 330 5740
   Email: b.short at elec.gla.ac.uk

<p><p><p><p>Short                    Expires July 7, 2003                  [Page 4]

Internet-Draft    draft-short-avt-rtp-vorbis-mime-00.txt   January 2003

<p>6. Full Copyright Statement

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph
   are included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

<p>7. Acknowledgement

   This document borrows from previous MIME type registrations,
   Internet-Drafts and RFCs. Thanks also to the Vorbis community.

<p><p><p>Short                    Expires July 7, 2003                  [Page 5]

-- 
Barry Short
Research Assistant
Centre for Music Technology
University of Glasgow
+44 (0)141 330 5740
B.Short at elec.gla.ac.uk

"If you can keep your head when all around are losing theirs, 
 perhaps you haven't quite grasped the gravity of the situation."
--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-dev-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.