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. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 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@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@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@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]