3GPP MIME Types: MIME Type Registrations for 3rd Generation Partnership Project (3GPP) Multimedia files
The media types that mark a file as 3GPP multimedia, so a server can serve it correctly.
Castagno, R. and D. Singer, "MIME Type Registrations for 3rd Generation Partnership Project (3GPP) Multimedia files", RFC 3839, DOI 10.17487/RFC3839, July 2004, <https://www.rfc-editor.org/info/rfc3839>.
@misc{rfc3839,
series = {Request for Comments},
number = 3839,
howpublished = {RFC 3839},
publisher = {RFC Editor},
doi = {10.17487/RFC3839},
url = {https://www.rfc-editor.org/info/rfc3839},
author = {R. Castagno and D. Singer},
title = {{MIME Type Registrations for 3rd Generation Partnership Project (3GPP) Multimedia files}},
pagetotal = 7,
year = 2004,
month = jul,
} RFC text
Contents
Network Working Group R. Castagno
Request for Comments: 3839 Nokia Mobile Phones
Category: Standards Track D. Singer
Apple Computer, Inc.
July 2004
MIME Type Registrations for
3rd Generation Partnership Project (3GPP) 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 (2004).
Abstract
This document serves to register and document the standard MIME types
associated with the 3GPP multimedia file format, which is part of the
family based on the ISO Media File Format.
1. Introduction
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 BCP 14, RFC 2119
[RFC2119].
The third-generation partnership project (3GPP) for third-generation
cellular telephony has defined a standard file format to contain
audio/visual sequences which may be downloaded to cellular phones
[3GPP]. At the time of writing, the 3GPP file format (3GP) can
contain H.263 or MPEG-4 video, and AMR Narrow-band speech, AMR wide-
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 here MUST contain a
brand defined in a standard issued by 3GPP that can apply to 3GPP
files, in their compatible brands list.
The MIME types defined here are needed to correctly identify such
files when they are served over HTTP, included in multi-part
documents, or used in other places where MIME types are used.
2. Security Considerations
The 3GPP 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 which 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 agreements based on World Intellectual Property
Organization (WIPO) treaties.
3GPP files have an extensible structure, so that it is theoretically
possible that metadata fields or media formats could be defined in
the future which could be used to induce particular actions on the
part of the recipient, thus presenting additional security risks.
However, this type of capability is currently not supported in the
referenced specification.
There is no current provision in the standards for encryption,
signing, or authentication of these file formats.
3. MIME Types
This registration applies to all files defined as using the '3GP'
file format and identified with a suitable brand in a 3GPP
specification. The usual file suffix for all these files is ".3gp".
3.1. Files with audio but no video
The type "audio/3gpp" 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/3gpp
MIME media type name: audio
MIME subtype name: 3gpp
Required parameters: none
Optional parameters: none
Ongoing work related to this
registration may introduce new
optional parameters. One example
area of effort may introduce a
parameter that would allow for
codecs in use within the MIME type
to be asserted and determined
without examination of the file.
Those with interests in the area
should monitor registrations for
updates.
Encoding considerations: files are 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 AMR audio
[RFC3267].
Security considerations: see the security considerations
section in RFC 3839
Interoperability considerations: The 3GPP organization has defined the
specification, interoperability, and
conformance, and conducts regular
interoperability testing.
Published specification: 3GPP 26.234, Release 5; 3GPP 26.244,
Release 6 or later. 3GPP
specifications are publicly
accessible at the 3GPP web site,
www.3gpp.org.
Applications which use this media type: Multi-media
Additional information: The type "audio/3gpp" 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 to be visual
material).
Magic number(s): None. However, the file-type box
must occur first in the file, and
MUST contain a 3GPP brand in its
compatible brands list.
File extension(s): 3gp and 3gpp are both declared at
http://www.nist.gov/nics/; 3gp is
preferred
Macintosh File Type Code(s): '3gpp'
Person & email address to contact for further information:
Nokia MIME manager, mime@nokia.com
Intended usage: COMMON
Change controller: 3GPP
3.2. Any files
The type "video/3gpp" is valid for all files. It is valid to serve
an audio-only file as "video/3gpp".
To: ietf-types@iana.org
Subject: Registration of Standard MIME media type video/3gpp
MIME media type name: video
MIME subtype name: 3gpp
Required parameters: none
Optional parameters: none
Encoding considerations: files are 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 AMR audio
[RFC3267].
Security considerations: see the security considerations
section in RFC 3839
Interoperability considerations: The 3GPP organization has defined the
specification, interoperability, and
conformance, and conducts regular
interoperability testing.
Published specification: 3GPP 26.234, Release 5; 3GPP 26.244,
Release 6 or later. 3GPP
specifications are publicly
accessible at the 3GPP web site,
www.3gpp.org.
Applications which 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 3GPP brand in its
compatible brands list.
File extension(s): 3gp and 3gpp are both declared at
http://www.nist.gov/nics/; 3gp is
preferred
Macintosh File Type Code(s): '3gpp'
Person & email address to contact for further information:
Nokia MIME manager, mime@nokia.com
Intended usage: COMMON
Change controller: 3GPP
4. IANA Considerations
This document registers the MIME types audio/3gpp and video/3gpp,
defined above.
5. Acknowledgments
The review of the 3GPP SA4 committee is gratefully acknowledged, in
particular Per Frojdh. The chairs of the AVT working group, in
particular Colin Perkins, have provided both excellent guidance and
feedback, for which the authors are grateful.
6. References
6.1. Normative References
[3GPP] Published specifications in releases 5 and 6: Release 5:
3GPP TS 26.234: Transparent end-to-end packet switched
streaming service (PSS); Protocols and codecs. Release 6:
3GPP TS 26.244: Transparent end-to-end packet switched
streaming service (PSS); 3GPP file format (3GP)
[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.
[RFC3267] Sjoberg, J., Westerlund, M., Lakaniemi, A. and Q. Xie,
"Real-Time Transport Protocol (RTP) Payload Format and File
Storage Format for the Adaptive Multi-Rate (AMR) and
Adaptive Multi-Rate WideBand (AMR-WB) Audio Codecs", RFC
3267, June 2002.
7. Authors' Contact Information
Roberto Castagno
Nokia Mobile Phones
PO Box 88, FIN-33721 Tampere
(Tieteenkatu 1, FIN-33720 Tampere)
Finland
Phone: +358 7180 35796
EMail: roberto.castagno@nokia.com
David Singer
Apple Computer, Inc.
One Infinite Loop, MS:302-3MT
Cupertino CA 95014
USA
Phone: +1 408 974 3162
EMail: singer@apple.com
8. Full Copyright Statement
Copyright (C) The Internet Society (2004). 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.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM 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.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights 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; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
ISO Plain Language
On this page
§1The 3GP File Format and Its Brands
The third-generation partnership project, 3GPP, has defined a standard file format for the audio and visual sequences that may be downloaded to cellular phones. At the time of writing, the 3GPP file format, 3GP, can contain H.263 or MPEG-4 video, AMR narrow-band speech, AMR wide-band speech or AAC audio, and 3GPP timed text.
Like all files in the ISO family, a 3GP file has an intrinsic file-type box at its start. That box identifies the specifications the file complies with, and it says which players, which may comply with only one specification, the content author permits to play the file. The identification is made with four-letter brands.
Files identified by the media types defined in this RFC must contain a brand defined in a 3GPP standard that can apply to 3GPP files, in their compatible brands list. The media types are needed to identify such files correctly when they are served over HTTP, included in multipart documents, or used in other places where media types are used.
A 3GP file starts with a box that names the standards it follows, using four-letter brands. The media type is the second half of the identification: it tells a server or a mail program what kind of file it is holding.
- H.263Video — One of the two video formats a 3GP file may contain.
- MPEG-4Video — The other video format a 3GP file may contain.
- AMRNarrow-band speech — Speech codec for narrow-band audio.
- AMR-WBWide-band speech — Speech codec for wide-band audio.
- AACAudio — Audio codec that a 3GP file may contain.
- 3GPP timed textText — Timed text, which is presented visually and so counts as visual material.
§2Security Considerations
The 3GPP file format may contain audio, video and displayable text data. There is currently no provision for active elements such as scripts of any kind.
It is clearly possible to author malicious files that call for an excessively large picture size or high sampling-rate audio. Clients can and usually do protect themselves against this kind of attack.
The RFC notes that selected metadata fields may hold information intended to protect the media against unauthorised use or distribution. In that case the intention is that altering or removing the data in the field would be treated as an offence under national agreements based on World Intellectual Property Organization treaties.
The 3GPP files have an extensible structure, so in theory metadata fields or media formats could be defined in the future that induce particular actions on the part of the recipient, and so present additional security risks. That kind of capability is not supported in the referenced specification at present. There is also no provision in the standards for encryption, signing or authentication of these file formats.
The format holds media and text, with nothing that runs. A file can still be built to be expensive to open, and the format has no way to encrypt or sign what it carries.
§3The Two Registered Media Types
The registration applies to all files defined as using the 3GP file format and identified with a suitable brand in a 3GPP specification. The usual file suffix for all of them is '.3gp'.
The type audio/3gpp may be used for files that contain audio but no visual presentation, neither video nor timed text. The type video/3gpp is valid for all files, and it is valid to serve an audio-only file as video/3gpp.
Both registrations share the same shape. Neither has required or optional parameters at the time of writing, though the RFC notes that ongoing work may introduce optional parameters, and gives one example area of effort: a parameter that would let the codecs in use within the media type be asserted and determined without examining the file. The files are binary and should be transmitted in a suitable encoding without CR and LF conversion or 7-bit stripping, and base64 is a suitable encoding. The RFC stresses that these media types are used only for files: separate types are used for real-time transfer, such as the RTP payload format for AMR audio and the RTP payload formats for H.263.
Both registrations name the same published specifications, 3GPP 26.234 Release 5 and 3GPP 26.244 Release 6 or later, note that the 3GPP organisation has defined the specification, interoperability and conformance and conducts regular interoperability testing, and list multi-media as the application. The contact for further information is the Nokia MIME manager, the intended usage is COMMON, and the change controller is 3GPP.
One type is for sound-only files and the other for anything. Both carry no parameters, both travel as base64 in mail, and both are managed by 3GPP.
| Property | audio/3gpp | video/3gpp |
|---|---|---|
| May hold audio | Yes | Yes |
| May hold video | No | Yes |
| May hold timed text | No, timed text counts as visual material | Yes |
| Required parameters | None | None |
| File extension THIS RFC | 3gp preferred, 3gpp also declared | 3gp preferred, 3gpp also declared |
§3.1The audio/3gpp Registration in Detail
The media type name is audio and the subtype name is 3gpp. The registration adds two conditions on use. The type may be used for files that contain audio but no visual presentation, and files served under this type must not contain any visual material. The RFC notes that 3GPP timed text is visually presented and is therefore counted as visual material.
There are no magic numbers as such, but the file-type box must occur first in the file and must contain a 3GPP brand in its compatible brands list. The file extensions 3gp and 3gpp are both declared at the NIST registry, with 3gp preferred. The Macintosh file type code is 3gpp.
The sound-only type is for files with no visual content at all, and timed text counts as visual. There is no fixed byte pattern to look for, but the file must open with the file-type box and a 3GPP brand in it.
§3.2The video/3gpp Registration in Detail
The media type name is video and the subtype name is 3gpp. This type is valid for all files, so an audio-only file may be served under it as well.
As with the audio type, there are no magic numbers, but the file-type box must occur first in the file and must contain a 3GPP brand in its compatible brands list. The file extensions 3gp and 3gpp are both declared at the NIST registry, with 3gp preferred, and the Macintosh file type code is 3gpp.
The general type covers every 3GP file, whatever is inside it. The same file-type box rule applies, and the same file extensions.
§4IANA Registration
The document registers the media types audio/3gpp and video/3gpp with IANA, as defined above.
IANA keeps the list of media types, and this RFC adds the two 3GPP entries to it.