RFC 4393 PROPOSED STANDARD MIME · MEDIA TYPES · MULTIMEDIA

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.

On rfc-editor.org ↗
PUBLISHED
March 2006
AUTHORS
H. Garudadri
STREAM
IETF
UPDATED BY
RFC 6381 — The 'Codecs' and 'Profiles' Parameters for "Bucket" Media Types
MIME TYPES REGISTERED
2
USUAL FILE SUFFIX
.3g2
FILE EXTENSIONS DECLARED
3g2 and 3gpp2, with 3g2 preferred
MACINTOSH FILE TYPE CODE
3gp2
MAGIC NUMBER
None
CHANGE CONTROLLER
3GPP2
DOI
10.17487/RFC4393

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗
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
   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.

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Acknowledgement

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   Administrative Support Activity (IASA).

ISO Plain Language

On this page
PROBLEMFiles in the 3GPP2 multimedia format had no registered media type, so a server had no agreed label to put on them.
MECHANISMThe document registers two media types, audio/3gpp2 for files with sound and no pictures, and video/3gpp2 for any file, and specifies that such a file must carry a 3GPP2 brand in the list of brands it is compatible with.
WHY IT MATTERSA 3G2 file can now be served and attached with a type that says what it holds. RFC 4393 was later updated by RFC 6381.

§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.

THE TWO REGISTERED MEDIA TYPES
audio/3gpp2video/3gpp2
For files with audio and no visual presentationValid for all files
MUST NOT contain any visual materialMay contain audio, video and timed text
An audio-only file may also be served as video/3gpp2 THIS RFCAn audio-only file may be served under this type
Intended usage: COMMONIntended 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.

THE DETAILS BOTH REGISTRATIONS SHARE
  • 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.

§7References