3GPP2 MIME Types: MIME Type Registrations for 3GPP2 Multimedia Files
Registers audio/3gpp2 and video/3gpp2 so 3G2 phone media files can be labeled correctly over HTTP and in multipart documents.
Garudadri, H., "MIME Type Registrations for 3GPP2 Multimedia Files", RFC 4393, DOI 10.17487/RFC4393, March 2006, <https://www.rfc-editor.org/info/rfc4393>.
@misc{rfc4393,
series = {Request for Comments},
number = 4393,
howpublished = {RFC 4393},
publisher = {RFC Editor},
doi = {10.17487/RFC4393},
url = {https://www.rfc-editor.org/info/rfc4393},
author = {H. Garudadri},
title = {{MIME Type Registrations for 3GPP2 Multimedia Files}},
pagetotal = 7,
year = 2006,
month = mar,
} RFC text
Contents
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.
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.
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: ietf-types@iana.org
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/>.
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, hgarudadri@qualcomm.com
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: ietf-types@iana.org
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]
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, hgarudadri@qualcomm.com
Intended usage:
COMMON
Change controller:
3GPP2
4. IANA Considerations
This document registers the MIME media types audio/3gpp2 and
video/3gpp2, defined above.
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: hgarudadri@qualcomm.com
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
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AI ELI5
On this page
§1Introduction
The third-generation partnership project 2 (3GPP2) defined a standard file format, called 3G2, for audio and visual sequences that can be downloaded to cellular phones. At the time of writing, it can hold H.263, H.264 or MPEG-4 video; 13K Vocoder, EVRC or AMR Narrow-band speech, or AAC audio; and 3GPP timed text.
Like all files in the ISO family, a 3G2 file has a file-type box that lists four-letter brands. Files labeled with the types in this RFC MUST list, in their compatible brands, a brand defined in a 3GPP2 standard. The MIME types are needed to identify such files when served over HTTP, included in multi-part documents or used elsewhere MIME types appear.
A phone video file has a tag inside saying what it is. The new labels outside the file let computers know what it is without opening it.
§3The Two Registered Types
The registration covers all files in the 3G2 format identified with a suitable brand in a 3GPP2 specification. The usual suffix is .3g2; the registrations also declare 3gpp2, with 3g2 preferred. The Macintosh file type code is '3gp2'.
audio/3gpp2 may be used for files containing audio but no visual presentation. Such files MUST NOT contain any visual material, and the RFC notes that 3GPP timed text counts as visual. video/3gpp2 is valid for all files, and it is valid to serve an audio-only file as video/3gpp2.
Both types have no required parameters and one optional parameter, Codecs, defined in RFC 4281. If the body contains another container format, Codecs MUST list all codecs of all formats, including contained ones. Both list the 3GPP2 specifications C.S0045 and C.S0050 as published specifications, and 3GPP2 is the change controller.
There are two labels. One says 'sound only', and the other says 'might have pictures'. The picture label also works for sound-only files.
§4Encoding and Identification
The data is binary. It should be transmitted in a suitable encoding without CR/LF conversion or 7-bit stripping; base64 is a suitable encoding. These types are for files only. Real-time transfer uses separate types, such as the RTP payload formats for 13K vocoder speech (RFC 2658) and, for video, H.263 (RFC 2429).
There is no magic number as such. However, the file-type box must occur first in the file and MUST contain a 3GPP2 brand in its compatible brands list.
These files are not plain text, so they must be sent without anyone fiddling with the bytes. The first thing inside the file says what kind it is.
§2Security Considerations
The format can hold audio, video and displayable text, and has no provision for active elements such as scripts. Files could still be crafted to demand an excessively large picture size or high sampling-rate audio, though clients can and usually do protect themselves.
Some metadata fields may carry information meant to protect media against unauthorized use, and altering or removing it is intended to be treated as an offense under WIPO treaties. The format is extensible, so future fields could in theory induce actions in the recipient, but the referenced specification does not support that. Encryption, signing or authentication can be done with any media-independent transformation.
The files only hold sound, pictures and text, not programs. A bad file might be oversized to cause trouble, but players are usually careful.
§3.1Interoperability and Conformance
Both registrations say that 3GPP2 defined the specification of the media format. Interoperability and conformance testing is done in cooperation with other bodies, including the Open Mobile Alliance (OMA) and the International Multimedia Telecommunications Consortium (IMTC). The intended usage is COMMON and the application area is listed as multi-media.
Several groups work together to check that phones and players all understand these files the same way.
§4IANA Considerations
The only IANA action is to register the two MIME media types audio/3gpp2 and video/3gpp2, as defined in the document. The RFC used RFC 3839 as a template for the registrations.
The official list of labels gets two new entries, and that is all this RFC asks for.