Audio-Video Transport WG Y Lim, D. Singer
Internet Draft net&tv, Apple Computer
Document: draft-lim-mpeg4-mime-03 October 2004
Category: Expires March 2005
MIME Type Registration for MPEG-4
Status of this Memo
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Abstract
This document defines the standard MIME types associated with MP4
files. This also document recommended use of registered MIME types
according to the type of contents.
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Table of Contents
1. Introduction...................................................3
2. Selection of MIME types for MP4 files..........................3
3. IANA Considerations............................................4
3.1 MP4 file with visual presentation..........................4
3.2 MP4 file without visual presentation.......................5
3.3 MP4 file without visual presentation.......................6
3.4 IOD in binary format.......................................7
3.5 IOD in textual format......................................8
4. Security Considerations........................................9
5. Acknowledgments................................................9
6. Full Copyright Statement......................................10
7. Intellectual Property Notice..................................10
8. References....................................................11
9. Author's Addresses............................................11
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1. Introduction
This document describes 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[3]. It includes interactive scene management, visual and
audio representations as well as systems functionality like
multiplexing, synchronization, and an object descriptor framework.
The historical approach for MPEG data is 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)
includes a standard file type for encapsulating ISO/IEC 14496 data.
This file type can be used in a number of ways: perhaps the most
important are its use as an interchange format for ISO/IEC 14496
data, its use 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.
2. Selection of MIME types for MP4 file
The MIME types to be assigned to MP4 files are selected based on the
contents. Basic guidelines of 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 which have MPEG-J etc. in
addition to video or audio streams, video/mp4 should be used,
although:
c) for files with audio but no visual aspect, including those which
have MPEG-J etc. in addition to audio streams, audio/mp4 may be used.
In either case, these indicate files conforming to the "MP4"
specification (ISO/IEC 14496-1:2000, systems file format).
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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.
3.1 MP4 file
MIME media type name: video
MIME subtype name: mp4
Required parameters: none
Optional parameters: none
Encoding considerations: base64 generally preferred; files are
binary and should be transmitted without CR/LF conversion, 7-bit
stripping etc.
Security considerations: See section 5 of RFC XXXX
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
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 generally preferred; files are
binary and should be transmitted without CR/LF conversion, 7-bit
stripping etc.
Security considerations: See section 5 of RFC XXXX
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
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 generally preferred; files are
binary and should be transmitted without CR/LF conversion, 7-bit
stripping etc.
Security considerations: See section 5 of RFC XXXX
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
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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3.4 IOD in binary format
MIME media type name: application
MIME subtype name: mpeg4-iod
Required parameters: none
Optional parameters: none
Encoding considerations: base64 generally preferred; files are
binary and should be transmitted without CR/LF conversion, 7-bit
stripping etc.
Security considerations: See section 5 of RFC XXXX
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
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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3.5 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 XXXX
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
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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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 which 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.
MP4 file supports storage of stream types including commands that
are executed on the terminal like OD commands, BIFS commands, etc.
and programmatic content like 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 or temporarily make the
receiver unavailable.
Authentication mechanisms can be used to validate of the sender and
the data to prevent security problems due to non-compliant malignant
MP4 file.
A security model is defined in ISO/IEC 14496 Systems MP4 files
containing MPEG-J contents which comprises Java(TM) classes and
objects. MPEG-J defines a set of Java 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, define native methods,
start programs, read or write files, or read system properties.
5. Acknowledgments
This draft 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.
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6. 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.
7. Intellectual Property Notice
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8. References
8.1 Normative References
[1]Bradner, S., "The Internet Standards Process -- Revision 3", BCP
9, RFC 2026, October 1996.
[2]Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997
[3]H. Schulzrinne, et. al., "RTP : A Transport Protocol for Real-Time
Applications", IETF RFC 1889, January 1996.
[4]ISO/IEC 14496-1 "Information technology - Coding of audio-visual
objects - Part 1 : Systems", 3rd ed. 2004
[5]ISO/IEC 14496-12 "Information technology - Coding of audio-visual
objects - Part 12 : ISO Base Media File Format", December 2003
[6]ISO/IEC 14496-14 "Information technology - Coding of audio-visual
objects - Part 14 : MP4 File Format", January 2004
[7]ISO/IEC 14496-15 "Information technology - Coding of audio-visual
objects - Part 15 : AVC File Format", 2004
9. Author's Addresses
Young-Kwon LIM
net&tv Inc.
Room 802 Hanseo Building
1582-6 Seocho-3-Dong Seocho-Gu
Seoul, 137-875, Korea
E-mail : young@netntv.co.kr
TEL : +82-2-581-2305
David Singer
Apple Computer, Inc.
One Infinite Loop, MS:302-3MT
Cupertino CA 95014
USA
Email: singer@apple.com
Tel: +1 408 974 3162
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