





Network Working Group                                             Y. Lim
Request for Comments: 4337                                   net&tv Inc.
Category: Standards Track                                      D. Singer
                                                          Apple Computer
                                                              March 2006


                   MIME Type Registration for MPEG-4

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 defines the standard MIME types associated with MP4
   files.  It also recommends use of registered MIME types according to
   the type of contents.

Table of Contents

   1. Introduction ....................................................2
   2. Selection of MIME Types for MP4 Files ...........................3
   3. IANA Considerations .............................................3
      3.1. MP4 File ...................................................4
      3.2. MP4 File with Audio but without Visual Presentation ........5
      3.3. MP4 File with MPEG-4 System Stream and neither
           Visual nor Audio Presentation ..............................6
      3.4. Initial Object Descriptor (IOD) in Binary Format ...........7
      3.5. Initial Object Descriptor (IOD) in Textual Format ..........8
   4. Security Considerations .........................................9
   5. Acknowledgements ................................................9
   6. Normative References ............................................9










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1.  Introduction

   This document describes a standard definition of MIME types
   associated with MP4 files and the guidelines for using them.

   MPEG-4 (ISO/IEC 14496) is a standard designed for the representation
   and delivery of multimedia information over a variety of transport
   protocols [1].  It includes interactive scene management and visual
   and audio representations, as well as system functionality like
   multiplexing, synchronization, and an object descriptor framework
   [2].

   The historical approach for MPEG data has been to declare it under
   "video", and this approach is followed for ISO/IEC 14496.  In
   addition, some MIME types are defined under "audio" and "application"
   for the streams not containing visual presentation.

   Amendment 1 of the ISO/IEC 14496 standard (also known as version 2)
   introduced a standard file type, called MP4 files, for encapsulating
   ISO/IEC 14496 data.  This is now separately specified as the MP4 file
   format [4], which in turn is based on the ISO base media file format
   [3].  A separate specification [5] covers the storage of Advanced
   Video Coding (AVC) (also known as H.264) [6] material in files based
   on the ISO base media file format.  The MP4 file type can be used in
   a number of ways; perhaps the most important of these is its use as
   an interchange format for ISO/IEC 14496 data, as a content-download
   format, and as the format read by streaming media servers.

   These first two uses will be greatly facilitated if there is a
   standard MIME type for serving these files (e.g., over HTTP).

   The ISO/IEC 14496 standard is broad, and therefore the type of data
   that may be in such a file can vary.  In brief, simple compressed
   video and audio (using a number of different compression algorithms)
   can be included; interactive scene information; meta-data about the
   presentation; references to ISO/IEC 14496 media streams outside the
   file and so on.  Different top-level MIME types are used to identify
   the type of the contents in the file.













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RFC 4337                   MPEG-4 MIME Types                  March 2006


2.  Selection of MIME Types for MP4 Files

   The MIME types to be assigned to MP4 files are selected according to
   the contents.  Basic guidelines for selecting MIME types are as
   follows:

   a) if the file contains neither visual nor audio presentations, but
      only, for example, MPEG-J or MPEG-7, use application/mp4;

   b) for all other files, including those that have MPEG-J, etc., in
      addition to video or audio streams, video/mp4 should be used;
      however:

   c) for files with audio but no visual aspect, including those that
      have MPEG-J, etc., in addition to audio streams, audio/mp4 may be
      used.

   In any case, these indicate files conforming to the "MP4"
   specification, ISO/IEC 14496-1:2000, systems file format.

3.  IANA Considerations

   This section describes the MIME types and names to be used with
   various MPEG-4 contents.  Sections from 4.1 to 4.5 register five new
   MIME types with the IANA.


























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3.1.  MP4 File

   MIME media type name: video

   MIME subtype name: mp4

   Required parameters: none

   Optional parameters: none

   Encoding considerations: base64 IS generally preferred; files are
      binary and should be transmitted without CR/LF conversion, 7-bit
      stripping, etc.

   Security considerations: See section 5 of RFC 4337.

   Interoperability considerations: A number of interoperating
      implementations exist within the ISO/IEC 14496 community, and that
      community has reference software for reading and writing the file
      format.

   Published specification: ISO/IEC 14496-1:2001.

   Applications: Multimedia

   Additional information:

      Magic number(s): none

      File extension(s): mp4 and mpg4 are both declared at
         <http://pitch.nist.gov/nics/>.

      Macintosh File Type Code(s): mpg4 is registered with Apple.

   Person to contact for info: David Singer, singer@apple.com

   Intended usage: Common

   Author/Change controller: David Singer, ISO/IEC 14496 file format
      chair











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3.2.  MP4 File with Audio but without Visual Presentation

   MIME media type name: audio

   MIME subtype name: mp4

   Required parameters: none

   Optional parameters: none

   Encoding considerations: base64 IS generally preferred; files are
      binary and should be transmitted without CR/LF conversion, 7-bit
      stripping, etc.

   Security considerations: See section 5 of RFC 4337.

   Interoperability considerations: A number of interoperating
      implementations exist within the ISO/IEC 14496 community, and that
      community has reference software for reading and writing the file
      format.

   Published specification: ISO/IEC 14496-1:2001.

   Applications: Multimedia

   Additional information:

      Magic number(s): none

      File extension(s): mp4 and mpg4 are both declared at
         <http://pitch.nist.gov/nics/>.

      Macintosh File Type Code(s): mpg4 is registered with Apple.

   Person to contact for info: David Singer, singer@apple.com

   Intended usage: Common

   Author/Change controller: David Singer, ISO/IEC 14496 file format
      chair.











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3.3.  MP4 File with MPEG-4 System Stream and neither Visual nor
      Audio Presentation

   MIME media type name:application

   MIME subtype name: mp4

   Required parameters: none

   Optional parameters: none

   Encoding considerations: base64 IS generally preferred; files are
      binary and should be transmitted without CR/LF conversion, 7-bit
      stripping, etc.

   Security considerations: See section 5 of RFC 4337.

   Interoperability considerations: A number of interoperating
      implementations exist within the ISO/IEC 14496 community, and that
      community has reference software for reading and writing the file
      format.

   Published specification: ISO/IEC 14496-1:2001.

   Applications: Multimedia

   Additional information:

      Magic number(s): none

      File extension(s): mp4 and mpg4 are both declared at
         <http://pitch.nist.gov/nics/>.

      Macintosh File Type Code(s): mpg4 is registered with Apple.

   Person to contact for info: David Singer, singer@apple.com

   Intended usage: Common

   Author/Change controller: David Singer, ISO/IEC 14496 file format
      chair










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RFC 4337                   MPEG-4 MIME Types                  March 2006


3.4.  Initial Object Descriptor (IOD) in Binary Format

   MIME media type name: application

   MIME subtype name: mpeg4-iod

   Required parameters: none

   Optional parameters: none

   Encoding considerations: base64 is generally preferred; files are
      binary and should be transmitted without CR/LF conversion, 7-bit
      stripping, etc.

   Security considerations: See section 5 of RFC 4337.

   Interoperability considerations: A number of interoperating
      implementations exist within the ISO/IEC 14496 community, and that
      community has reference software for reading and writing the file
      format.

   Published specification: ISO/IEC 14496-1:2001

      Applications: Multimedia

      Additional information:

      Magic number(s): none

      File extension(s): none mp4 and mpg4 are both declared at
         <http://pitch.nist.gov/nics/>.

      Macintosh File Type Code(s): mpg4 is registered with Apple.

   Person to contact for info: David Singer, singer@apple.com

   Intended usage: Common

   Author/Change controller: David Singer, ISO/IEC 14496 file format
      chair











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RFC 4337                   MPEG-4 MIME Types                  March 2006


3.5.  Initial Object Descriptor (IOD) in Textual Format

   MIME media type name: application

   MIME subtype name: mpeg4-iod-xmt

   Required parameters: none

   Optional parameters: none

   Encoding considerations: none

   Security considerations: See section 5 of RFC 4337.

   Interoperability considerations: A number of interoperating
      implementations exist within the ISO/IEC 14496 community, and that
      community has reference software for reading and writing the file
      format.

   Published specification: ISO/IEC 14496-1:2001 AMD2.

   Applications: Multimedia

   Additional information:

      Magic number(s): none

      File extension(s): mp4 and mpg4 are both declared at
         <http://pitch.nist.gov/nics/>.

      Macintosh File Type Code(s): mpg4 is registered with Apple.

   Person to contact for info: David Singer, singer@apple.com

   Intended usage: Common

   Author/Change controller: David Singer, ISO/IEC 14496 file format
      chair













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RFC 4337                   MPEG-4 MIME Types                  March 2006


4.  Security Considerations

   It is possible to inject non-compliant MPEG streams (Audio, Video,
   and Systems) in the MP4 file to overload the receiver/decoder's
   buffers.  This might compromise the functionality of the receiver or
   even crash it.  This is especially true for end-to-end systems like
   MPEG, where the buffer models are precisely defined.

   An MP4 file supports the storage of stream types, including commands
   that are executed on the terminal such as OD command and BIFS
   commands, and programmatic content such as MPEG-J (Java(TM) Byte
   Code) and ECMASCRIPT.  It is possible to use one or more of the above
   in a manner non-compliant to MPEG to crash the receiver or
   temporarily make it unavailable.

   Authentication mechanisms can be used to validate of the sender and
   the data to prevent security problems due to non-compliant malignant
   MP4 files.

   A security model is defined in ISO/IEC 14496 Systems MP4 files
   containing MPEG-J contents that comprises Java(TM) classes and
   objects.  MPEG-J defines a set of Java(TM) APIs and a secure
   execution model.  MPEG-J content can call this set of APIs and
   Java(TM) methods from a set of Java packages supported in the
   receiver within the defined security model.  According to this
   security model, downloaded byte code is forbidden to load libraries,
   to define native methods, to start programs, to read or write files,
   or to read system properties.

5.  Acknowledgements

   This document has benefited greatly by contributions from many
   people, including Mike Coleman, Jean-Claude Duford, Viswanathan
   Swaminathan, Peter Westerink, Carsten Herpel, Olivier Avaro, Paul
   Christ, Zvi Lifshitz, and many others.  Their insight, foresight, and
   contribution is gratefully acknowledged.  Little has been invented
   here by the author; this is mostly a collation of greatness that has
   gone before.

6.  Normative References

   [1]  Schulzrinne, H.,  Casner, S., Frederick, R., and V. Jacobson,
        "RTP: A Transport Protocol for Real-Time Applications", STD 64,
        RFC 3550, July 2003.

   [2]  ISO/IEC 14496-1 "Information technology - Coding of audio-visual
        objects - Part 1 : Systems", 3rd ed. 2004.




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RFC 4337                   MPEG-4 MIME Types                  March 2006


   [3]  ISO/IEC 14496-12 "Information technology - Coding of audio-
        visual objects - Part 12 : ISO Base Media File Format", December
        2003.

   [4]  ISO/IEC 14496-14 "Information technology - Coding of audio-
        visual objects - Part 14 : MP4 File Format", January 2004.

   [5]  ISO/IEC 14496-15 "Information technology - Coding of audio-
        visual objects - Part 15 : AVC File Format", 2004.

   [6]  ISO/IEC 14496-10:2004 "Information technology -- Coding of
        audio-visual objects -- Part 10: Advanced Video Coding", 2nd
        edition, 2004.

Authors' Addresses

   Young-Kwon LIM
   net&tv Inc.
   Room 802 Hanseo Building
   1582-6 Seocho-3-Dong Seocho-Gu
   Seoul, 137-875, Korea

   Phone: +82-2-581-2305
   EMail: young@netntv.co.kr


   David Singer
   Apple Computer, Inc.
   One Infinite Loop, MS:302-3MT
   Cupertino  CA 95014
   USA

   Phone: +1 408 974 3162
   EMail: singer@apple.com

















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RFC 4337                   MPEG-4 MIME Types                  March 2006


Full Copyright Statement

   Copyright (C) The Internet Society (2006).

   This document is subject to the rights, licenses and restrictions
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   Administrative Support Activity (IASA).







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