Network Working Group L. Walleij
Request for Comments: 3534 The Ogg Vorbis Community
Category: Standards Track May 2003

The application/ogg Media Type

Status of this Memo

This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

The Ogg Bitstream Format aims at becoming a general, freely-available
standard for transporting multimedia content across computing
platforms and networks. The intention of this document is to define
the MIME media type application/ogg to refer to this kind of content
when transported across the Internet. It is the intention of the Ogg
Bitstream Format developers that it be usable without intellectual
property concerns.

Conventions used in this Document

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 RFC2119 [2].

1. The Ogg Bitstream Format

The Ogg Bitstream format has been developed as a part of a larger
project aimed at creating a set of components for the coding and
decoding of multimedia content (codecs) which are to be freely
available and freely re-implementable both in software and in
hardware for the computing community at large, including the Internet
community.

Raw packets from these codecs may be used directly by transport
mechanisms that provide their own framing and packet-separation
mechanisms (sUCh as UDP datagrams).

One such framing and content-separation mechanism is the real-time
transport protocol (RTP). RTP allows the streaming of synchronous
lossy data for broadcasting and similar purposes. If this function
is desired then a separate RTP wrapping mechanism should be used. A
wrapping mechanism is currently under development.

For stream based storage (such as files) and transport (such as TCP
streams or pipes), Ogg codecs use the Ogg Bitstream Format to provide
framing/sync, sync recapture after error, landmarks during seeking,
and enough information to properly separate data back into packets at
the original packet boundaries without relying on decoding to find
packet boundaries. The application/ogg MIME type refers to this kind
of bitstreams, when no further knowledge of the bitstream content
exists.

The bitstream format in itself is documented in [1].

2. Registration Information

To: ietf-types@iana.org

Subject: Registration of MIME media type application/ogg

MIME media type name: application

MIME suBType name: ogg

Required parameters: none

Optional parameters: none

Encoding Considerations:

The Ogg bitstream format is binary data, and must be encoded for
non-binary transport; the Base64 encoding is suitable for Email.
Binary encoding could also be used.

Security Considerations:

As the Ogg bitstream file is a container format and only a carrier of
content (such as Vorbis audio) with a very rigid definition (see
[1]), this format in itself is not more vulnerable than any other
content framing mechanism. The main security consideration for the
receiving application is to ensure that manipulated packages can not
cause buffer overflows and the like. It is possible to encapsulate
even executable content in the bitstream, so for such uses additional
security considerations must be taken.

Ogg bitstream files are not signed or encrypted using any applicable
encryption schemes. External security mechanisms must be added if
content confidentiality and authenticity is to be achieved.

Interoperability considerations:

The Ogg bitstream format has proved to be widely implementable across
different computing platforms. A broadly portable reference
implementation is available under a BSD license.

The Ogg bitstream format is not patented and can be implemented by
third parties without patent considerations.

Published specification:

See [1].

Applications which use this media type:

Any application that implements the specification will be able to
encode or decode Ogg bitstream files. Specifically, the format is
supposed to be used by subcodecs that implement, for example, Vorbis
audio.

Additional information:

Magic number(s):

In Ogg bitstream files, the first four bytes are 0x4f 0x67 0x67 0x53
corresponding to the string "OggS".

File extension: .ogg

Macintosh File Type Code(s): OggS

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

Person & email address to contact for further information:

Questions about this proposal should be directed to Linus Walleij
<triad@df.lth.se>. Technical questions about the Ogg bitstream
standard may be asked on the mailing lists for the developer
community. <http://www.xiph.org/archives/>

Intended usage: COMMON

Author/Change controller:

This document was written by Linus Walleij <triad@df.lth.se>.
Changes to this document will either be handled by him, a
representative of the Xiph.org, or the associated development
communities.

The Ogg bitstream format is controlled by the Xiph.org and the
respective development communities.

3. Security Considerations

Security considerations are discussed in the security considerations
clause of the MIME registration in section 2.

4. Normative References

[1] Pfeiffer, S., "The Ogg encapsulation format version 0", RFC
3533, May 2003.

[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC2119, March 1997.

5. Intellectual Property Statement

The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.

The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.

6. Author's Address

Linus Walleij
The Ogg Vorbis Community
Master Olofs Vag 24
Lund 224 66
SE

Phone: +46 703 193678
EMail: triad@df.lth.se
URI: http://www.xiph.org/

7. Full Copyright Statement

Copyright (C) The Internet Society (2003). All Rights Reserved.

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Acknowledgement

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