Please review: audio/sp-midi MIME type registration
matti.s.hamalainen at nokia.com
matti.s.hamalainen at nokia.com
Fri Jul 19 23:01:57 CEST 2002
M. Hamalainen
Internet Draft Nokia
Document: draft-SP-MIDI-MIME-type-01.txt T. White
MMA
Expires: January 2003 July 2002
Registration of MIME media type audio/sp-midi
Status of this Memo
This document is an Internet-Draft and is subject to all provisions
of Section 10 of RFC2026 except that the right to produce derivative
works is not granted.
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Abstract
MIDI Manufacturers Association (MMA) and Association of Music
Electronics industry (AMEI) have recently produced the Scalable
Polyphony MIDI (SP-MIDI) standard [1]. The SP-MIDI standard has been
developed in particularly for mobile MIDI applications. SP-MIDI has
been approved for 3GPP standardization and a dedicated SP-MIDI
profile has been defined for 3GPP SP-MIDI devices [2]. Since MIDI
information is a very compact media type 3GPP is initially focusing
on the application of SP-MIDI for music downloading and messaging
applications that require MIME registration.
1 Introduction
Hamalainen & White [Page 1]
SP-MIDI MIME July, 2002
MIDI content is commonly used in the Internet, however such use is
based on informal ad hoc MIME type definitions that have not been
registered by IETF. The present MIME type registration is harmonized
with the typical Internet usage of unregistered audio/midi and
audio/x-midi MIME types. Commonly MIDI information is stored in the
Standard MIDI File (SMF) format [3]. The present MIME type
registration also uses the SMF file format for the encapsulation of
SP-MIDI data. Whereas previous MIDI specifications have been based
on common minimum requirements for all playback devices supporting
the same specification, SP-MIDI is able to support a wider range of
playback devices because playback adaptations can be encoded in the
MIDI content. Due to these differences, a separate MIME type,
audio/sp-midi, needs to be registered to distinguish SP-MIDI
content.
2 Registration of audio/sp-midi
MIME media type name: audio
MIME subtype name: sp-midi
Required parameters: none
Optional parameters: none
Encoding considerations:
sp-midi data is binary data and must be encoded for non-binary
transport; Base64 is suitable for Email
Security considerations:
Many synthetic audio compositions have associated intellectual
property rights. It is conceivable that rights owners of sp-
midi content will want to protect their rights by applying
security mechanisms that prohibit the rendering of the content
without a legally acquired license to do so. These mechanisms
would be applied externally to the Content-Type defined here;
sp-midi content itself is not encrypted internally. sp-midi
streams don not contain executable content.
Hamalainen & White January 2003 [Page 2]
SP-MIDI MIME July, 2002
Interoperability considerations:
Scalable Polyphony MIDI (SP-MIDI) is a Musical Instrument
Digital Interface (MIDI) specification developed by MMA and
AMEI. SP-MIDI is based on the MIDI 1.0 specification [3] which
standardizes a protocol for the electronic transmission of
music as data suitable for communication between a transmitter
and receiver using MIDI messages. SP-MIDI data is stored in
Standard MIDI Files (SMF) [3].
The SP-MIDI format [1] provides scalable representation of MIDI
content which enables broadly interoperable music applications.
SP-MIDI files have encoded information about playback
requirements which allows SP-MIDI playback devices with
different device capabilities to play the same content
according to composer's polyphony requirement and Channel
priority order definitions. SP-MIDI player requirements are
defined in separate SP-MIDI profile specifications [2] defining
the supported MIDI messages and device requirement. All SP-MIDI
profiles follow the definitions of the SP-MIDI specification
[1].
MMA and AMEI have previously defined the General MIDI (GM)
system standards GM1 [4] GM2 [5], and GML [6]. These
specifications are technically related to the SP-MIDI
specification, but do not support polyphony scalability. Due to
the differences between GM and SP-MIDI systems GM synthesizers
do not support all SP-MIDI content, and likewise not all SP-
MIDI synthesizers support all GM content. Thus a separate MIME
definition is needed to distinguish SP-MIDI, media from the
informally used audio/midi content.
Published specification:
There are no previous RFC documents on SP-MIDI.
Applications which use this media type:
SP-MIDI is a synthetic audio format for the flexible
presentation of MIDI data on a wide range of playback devices,
particularly portable appliances such as mobile phones, PDAs,
and palmtop computers.
Hamalainen & White January 2003 [Page 3]
SP-MIDI MIME July, 2002
Additional information:
Magic number(s):
First four bytes (1-4): \115\124\150\144,
byte (24): \360,
byte (26): \177,
bytes (28-29): \013\001
File extension(s): mid
Macintosh File Type Code(s): mid
Intended usage: COMMON
3 IANA Considerations
Section 2 of this document registers one MIME subtype.
4 Security Considerations
Security considerations are specified in the MIME subtype
registration contained in Section 2.
5 Authors' Addresses
Matti Hamalainen
Nokia
P.O. Box 100 (Visiokatu 1)
FIN-33721 Tampere, Finland
Tel: +358 7180 35789
Fax: +358 7180 35899
Email: matti.s.hamalainen at nokia.com
Tom White,
MIDI Manufacturers Association
P.O. Box 3173
La Habra CA
90632-3173
Tel (714) 736-9774
Fax (714) 736-9775
Email: mma at midi.org
Hamalainen & White January 2003 [Page 4]
SP-MIDI MIME July, 2002
Author/Change controller:
Matti Hamalainen
Nokia
P.O. Box 100 (Visiokatu 1)
FIN-33721 Tampere, Finland
Tel: +358 7180 35789
Fax: +358 7180 35899
matti.s.hamalainen at nokia.com
References
1 Scalable Polyphony MIDI Specification. December 2001, RP-034, The
MIDI Manufacturers Association, Los Angeles, CA, USA.
2 Scalable Polyphony MIDI Device 5-24 Note Profile for 3GPP,
December 2001, RP-035, The MIDI Manufacturers Association, Los
Angeles, CA, USA.
3 MIDI 1.0 Detailed Specification, Document Version 4.2. February
1996, In 'The Complete MIDI 1.0 Detailed Specification, Document
Version 96.1.' The MIDI Manufacturers Association., Los Angeles,
CA, USA.
4 General MIDI System Level 1. 1994, MMA0007/RP003, In 'The Complete
MIDI 1.0 Detailed Specification, Document Version 96.1.' The MIDI
Manufacturers Association, Los Angeles, CA, USA.
5 General MIDI Level 2 Specification (Recommended Practice).
November 1999, RP-024, The MIDI Manufacturers Association, Los
Angeles, CA, USA.
6 General MIDI Lite, Specification for GM Lite and Guidelines for
Use In Mobile Applications. October 5, 2001, RP-033, Version 1.0,
The MIDI Manufacturers Association, Los Angeles, CA, USA.
Hamalainen & White January 2003 [Page 5]
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