Network Working Group H. Garudadri

Network Working Group H. Garudadri
Request for Comments: 4393 QUALCOMM
Category: Standards Track March 2006

MIME Type Registrations for 3GPP2 Multimedia Files

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 (2006).

Abstract

This document serves to register and document the standard MIME types
associated with the 3GPP2 multimedia file format, which is part of
the family based on the ISO Media File Format.

Table of Contents

1. Introduction ....................................................1
1.1. Conventions Used in This Document ..........................2
2. Security Considerations .........................................2
3. MIME Types ......................................................3
3.1. Files with Audio but No Video ..............................3
3.2. Any Files ..................................................4
4. IANA Considerations .............................................5
5. Acknowledgements ................................................6
6. References ......................................................6
6.1. Normative References .......................................6
6.2. Informative References .....................................6

1. Introduction

The third-generation partnership project 2 (3GPP2) for 3rd generation
cellular telephony has defined a standard file format to contain
audio/visual sequences that may be downloaded to cellular phones
[3gpp2]. At the time of writing, the 3GPP2 file format (3G2) can
contain H.263, H.264, or MPEG-4 video; and 13K Vocoder, EVRC or AMR
Narrow-band speech, or AAC audio; and 3GPP timed text.

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RFC 4393 3GPP2 Multimedia Registrations March 2006

Within the file, as with all files in the 'ISO' family, there is an
intrinsic file-type box, which identifies those specifications to
which the file complies, and which players (possibly compliant with
only one specification) are permitted by the content author to play
the file. This identification is through four-letter 'brands'.
Files identified by the MIME [MIME1] type defined in this document
MUST contain, in their compatible brands list, a brand defined in a
standard (issued by 3GPP2) that can apply to 3GPP2 files.

The MIME types defined in this document are needed correctly to
identify such files when they are served over HTTP, included in
multi-part documents, or used in other places where MIME types are
used.

1.1. Conventions Used in This Document

In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in RFC 2119
[RFC2119].

2. Security Considerations

The 3GPP2 file format may contain audio, video, and displayable text
data. There is currently no provision for 'active' elements (such as
scripts) of any kind.

Clearly, it is possible to author malicious files that attempt to
call for an excessively large picture size, high sampling-rate audio,
etc. However, clients can and usually do protect themselves against
this kind of attack.

It should be noted that selected metadata fields may encompass
information partly intended to protect the media against unauthorized
use or distribution. In this case, the intention is that alteration
or removal of the data in the field would be treated as an offense
under national agreement-based World Intellectual Property
Organization (WIPO) treaties.

3GPP2 files have an extensible structure, so it is theoretically
possible that metadata fields or media formats could be defined in
the future that could be used to induce particular actions on the
part of the recipient, thus presenting additional security risks; but
this type of capability is currently not supported in the referenced
specification.

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RFC 4393 3GPP2 Multimedia Registrations March 2006

Encryption, signing, or authentication of these file formats can be
done using any media-independent transformations of the file or media
data.

3. MIME Types

This registration applies to all files defined as using the '3G2'
file format and identified with a suitable brand in a 3GPP2
specification. The usual file suffix for all these files is ".3g2".

3.1. Files with Audio but No Video

The type "audio/3gpp2" may be used for files containing audio but no
visual presentation (neither video nor timed text, for example).

To: [email protected]
Subject: Registration of Standard MIME media type audio/3gpp2

MIME media type name:
audio
MIME subtype name:
3gpp2
Required parameters:
None.
Optional parameters:
Codecs. See [Bucket]. If the audio/3gpp2 body part contains
another container format, the Codecs parameter MUST list all
codecs indicated by all formats, including any contained formats.
Optional parameter values:
[3gpp2]
Encoding considerations:
This data is binary and should be transmitted in a suitable
encoding without CR/LF conversion, 7-bit stripping, etc.; base64
is a suitable encoding. Note that this MIME type is used only
for files; separate types are used for real-time transfer, such
as for the RTP payload format for 13K vocoder speech [RFC2658].
Security considerations:
See the security considerations section in RFC 4393 (this
document).
Interoperability considerations:
The 3GPP2 organization has defined the specification of the media
format [3gpp2]. Interoperability and conformance testing is done
in cooperation with other bodies, including the Open Mobile
Alliance (OMA) <http://www.openmobilealliance.org> and the
International Multimedia Telecommunications Consortium (IMTC)
<http://www.imtc.org/>.

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RFC 4393 3GPP2 Multimedia Registrations March 2006

Published specification:
3GPP2 C.S0045, 3GPP2 C.S0050 [3gpp2]
3GPP2 specifications are publicly accessible at the 3GPP2 web
site, <http://www.3gpp2.org>.
Applications that use this media type:
Multi-media
Additional information:
The type "audio/3gpp2" MAY be used for files containing audio but
no visual presentation. Files served under this type MUST NOT
contain any visual material. (Note that 3GPP timed text is
visually presented and is considered visual material).
Magic number(s):
None. However, the file-type box must occur first in the file,
and MUST contain a 3GPP2 brand in its compatible brands list.
File extension(s):
3g2 and 3gpp2 are both declared at <http://www.nist.gov/nics/>;
3g2 is preferred.
Macintosh file type code(s):
'3gp2'
Person & email address to contact for further information:
H. Garudadri, [email protected]
Intended usage:
COMMON
Change controller:
3GPP2

3.2. Any Files

The type "video/3gpp2" is valid for all files. It is valid to serve
an audio-only file as "video/3gpp2".

To: [email protected]
Subject: Registration of Standard MIME media type video/3gpp2

MIME media type name:
video
MIME subtype name:
3gpp2
Required parameters:
None
Optional parameters:
Codecs. See [Bucket]. If the video/3gpp2 body part contains
another container format, the Codecs parameter MUST list all
codecs indicated by all formats, including any contained formats.
Optional parameter values:
[3gpp2]

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RFC 4393 3GPP2 Multimedia Registrations March 2006

Encoding considerations:
This data is binary and should be transmitted in a suitable
encoding without CR/LF conversion, 7-bit stripping, etc.; base64
is a suitable encoding. Note that this MIME type is used only
for files; separate types are used for real-time transfer, such
as for the RTP payload formats for H.263 [RFC2429] and 13K
vocoder speech [RFC2658].
Security considerations:
See the security considerations section in RFC 4393 (this
document).
Interoperability considerations:
The 3GPP2 organization has defined the specification of the media
format [3gpp2]. Interoperability and conformance testing is done
in cooperation with other bodies, including the Open Mobile
Alliance (OMA) <http://www.openmobilealliance.org> and the
International Multimedia Telecommunications Consortium (IMTC)
<http://www.imtc.org/>.
Published specification:
3GPP2 C.S0045, 3GPP2 C.S0050 [3gpp2]

3GPP2 specifications are publicly accessible at the 3GPP2 web
site, <http://www.3gpp2.org>.
Applications that use this media type:
Multi-media
Additional information:
Magic number(s):
None. However, the file-type box must occur first in the file
and MUST contain a 3GPP2 brand in its compatible brands list.
File extension(s):
3g2 and 3gpp2 are both declared at <http://www.nist.gov/nics/>;
3g2 is preferred.
Macintosh file type code(s):
'3gp2'
Person & email address to contact for further information:
H.Garudadri, [email protected]
Intended usage:
COMMON
Change controller:
3GPP2

4. IANA Considerations

This document registers the MIME media types audio/3gpp2 and
video/3gpp2, defined above.

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RFC 4393 3GPP2 Multimedia Registrations March 2006

5. Acknowledgements

This document used RFC 3839 as a template. The authors of RFC 3839,
R. Castagno, and D. Singer, are gratefully acknowledged.

6. References

6.1. Normative References

[3gpp2] Published specifications: C.S0050: 3GPP2 File Formats for
Multimedia Services. C.S0045: Multimedia Messaging
Service (MMS) Media Format and Codecs for cdma2000 Spread
Spectrum Systems.

[Bucket] Gellens, R., Singer, D., and P. Frojdh, "The Codecs
Parameter for "Bucket" Media Types", RFC 4281, November
2005.

[MIME1] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

6.2. Informative References

[RFC2429] Bormann, C., Cline, L., Deisher, G., Gardos, T., Maciocco,
C., Newell, D., Ott, J., Sullivan, G., Wenger, S., and C.
Zhu, "RTP Payload Format for the 1998 Version of ITU-T Rec.
H.263 Video (H.263+)", RFC 2429, October 1998.

[RFC2658] McKay, K., "RTP Payload Format for PureVoice(tm) Audio",
RFC 2658, August 1999.

Author's Address

Harinath Garudadri
Qualcomm Inc
5775 Morehouse Dr.
San Diego, CA 92121

Phone: +1 858 651 6383
EMail: [email protected]

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RFC 4393 3GPP2 Multimedia Registrations March 2006

Full Copyright Statement

Copyright (C) The Internet Society (2006).

This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.

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Acknowledgement

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