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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ISO Plain Language
On this page
§1Introduction
The third-generation partnership project 2, for 3rd generation cellular telephony, has defined a standard file format to contain audio and visual sequences that may be downloaded to cellular phones. At the time of writing, the 3GPP2 file format, called 3G2, can contain H.263, H.264 or MPEG-4 video, 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 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.
Each 3G2 file lists the standards it follows, using short four-letter brand names, so that a player knows what it is allowed to do with it. The media type must not be used on a file that lacks a 3GPP2 brand.
§2Security 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, and so on. 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 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. 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.
There is nothing active in the format, so the risk is a file that asks for far more picture or sound than the device can handle. Players normally defend against that. Signing or encrypting the file is left to whatever mechanism the surrounding system uses.
§3The MIME Type Registration
The 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.
Both registrations share the same details. There are no required parameters. The optional parameter Codecs follows the bucket media types; if the body part contains another container format, the Codecs parameter MUST list all codecs indicated by all formats, including any contained formats. The optional parameter value is [3gpp2].
For encoding, the data is binary and should be transmitted in a suitable encoding without CR/LF conversion or 7-bit stripping, and base64 is a suitable encoding. The MIME types are used only for files; separate types are used for real-time transfer, such as the RTP payload format for 13K vocoder speech and the RTP payload formats for H.263.
For interoperability, the 3GPP2 organization has defined the specification of the media format, and interoperability and conformance testing is done in cooperation with other bodies, including the Open Mobile Alliance and the International Multimedia Telecommunications Consortium. The published specifications are 3GPP2 C.S0045 and 3GPP2 C.S0050. The application is Multi-media. There is no magic number, but the file-type box must occur first in the file and MUST contain a 3GPP2 brand in its compatible brands list. The file extensions 3g2 and 3gpp2 are both declared, and 3g2 is preferred. The Macintosh file type code is 3gp2. The intended usage is COMMON and the change controller is 3GPP2.
The two types share their settings: one optional parameter listing the codecs, base64 for text transport, no magic number, and the usual file extension.
| audio/3gpp2 | video/3gpp2 |
|---|---|
| For files with audio and no visual presentation | Valid for all files |
| MUST NOT contain any visual material | May contain audio, video and timed text |
| An audio-only file may also be served as video/3gpp2 THIS RFC | An audio-only file may be served under this type |
| Intended usage: COMMON | Intended usage: COMMON |
§3.1Files 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.
The additional information in the registration states that the type audio/3gpp2 MAY be used for files containing audio but no visual presentation, and that files served under this type MUST NOT contain any visual material. It notes that 3GPP timed text is visually presented and is considered visual material.
Use the audio label only when there is nothing to see. Timed text counts as something to see, so a file with captions is not an audio-only file.
- File suffixThe usual suffix for all these files is .3g2.
- BrandsThe compatible brands list must contain a brand defined in a 3GPP2 standard.
- Magic numberNone, but the file-type box must occur first in the file.
- Codecs parameterOptional, but it must list all codecs of any contained container formats.
- File extensions3g2 and 3gpp2 are both declared, and 3g2 is preferred.
- Macintosh file type code3gp2
§3.2Any Files
The type video/3gpp2 is valid for all files. It is valid to serve an audio-only file as video/3gpp2.
The registration repeats the shared details: no required parameters, the optional Codecs parameter that must list all codecs indicated by all formats when the body part contains another container format, binary encoding with base64 as a suitable encoding, no magic number but a file-type box that must occur first and must contain a 3GPP2 brand, the file extensions 3g2 and 3gpp2 with 3g2 preferred, the Macintosh file type code 3gp2, intended usage COMMON and change controller 3GPP2.
The video label works for anything, so a server can use it without inspecting the file. It is always safe to use, though it does not tell a client more than the file itself does.
§4IANA Considerations
This document registers the MIME media types audio/3gpp2 and video/3gpp2, defined above.
Two registrations, and that is all the document adds to the registry.