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Network Working Group T. Kosonen
Request for Comments: 4723 Nokia
Category: Informational T. White
MMA
December 2006
Registration of Media Type audio/mobile-xmf
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2006).
Abstract
The MIDI Manufacturers Association (MMA) and the Association of
Musical Electronics Industry (AMEI) have produced the Mobile XMF
standard, which was developed particularly for mobile MIDI
applications. Mobile XMF is a very compact media type providing
high-quality synthetic audio content for music downloading and
messaging applications that require MIME registration. This document
registers the media type audio/mobile-xmf.
Kosonen & White Informational [Page 1]
RFC 4723 Mobile XMF MIME December 2006 1. Introduction MIDI content is used commonly in the Internet. Typically, MIDI data is stored in the Standard MIDI File (SMF) format [8]. This MIME type registration uses the Mobile XMF file format for the encapsulation of SP-MIDI [3,4] and Mobile DLS (Downloadable Sounds) [2] data. The MIDI Manufacturers Association (MMA) and the Association of Musical Electronics Industry (AMEI) have produced the Mobile XMF standard [1], which was developed particularly for mobile MIDI [7] applications. 2. Registration of audio/mobile-xmf Type name: audio Subtype name: mobile-xmf Required parameters: none Optional parameters: revision: Mobile XMF file type revision ID revision is the Mobile XMF file type revision ID number from the XmfFileTypeRevisionID field of the XMF Meta File format 2.00. revision is encoded in hex in US-ASCII. prl: Playback resource list prl contains the playback resources included in all Content Description MetaDataItems of the Mobile XMF file. prl contains two-digit hexadecimal numbers representing data bytes from the Content Description Meta Data. Each resource is listed exactly once. A playback resource contains two parts: a prefix and data. prl is a sequence of two-digit hexadecimal numbers encoded in US-ASCII. Thus, prl has an even number of hexadecimal digits. Example: If the file includes Playback Resource Lists such as [00h 01h 00h 02h] and [00h 01h 00h 03h], the corresponding prl is 000100020003 containing playback resources 01, 02, and 03 each with the prefix 00. Kosonen & White Informational [Page 2]
RFC 4723 Mobile XMF MIME December 2006 minimum-pr: Minimum playback requirements minimum-pr contains the Maximum Instantaneous Resource (MIR) values from the first row of all MIR Count Tables corresponding to the playback resources listed in prl. Only the largest value from the values of the same resource is chosen. minimum-prl is a sequence of two-digit hexadecimal numbers encoded in US-ASCII. Thus, minimum-prl has an even number of hexadecimal digits. minimum-pr requires the use of prl, and the values in minimum-pr must be in the same order as the resources in prl. minimum-pr is the more important of minimum-pr and total-pr, because it defines the minimum playback requirements. Example: If the file includes the first rows of MIR Count Tables such as [02h 00h] and [01h 01h] corresponding to the above Playback Resource Lists, the corresponding minimum-pr is 020001. (02 is the largest of 2 and 1, 00 is the largest of 0, and 01 is the largest of 1.) total-pr: Total playback requirements total-pr contains the MIR values from the last row of all MIR Count Tables corresponding to the playback resources listed in prl. Only the largest value from the values of the same resource is chosen. total-pr is a sequence of two-digit hexadecimal numbers encoded in US-ASCII. Thus, total-pr has an even number of hexadecimal digits. total-pr requires the use of prl, and the values in total-pr must be in the same order as the resources in prl. Example: If the file includes the last rows of MIR Count Tables such as [05h 02h] and [06h 01h] corresponding to the above Playback Resource Lists, the corresponding total-pr is 060201. (06 is the largest of 5 and 6, 02 is the largest of 2, and 01 is the largest of 1.) Encoding considerations: mobile-xmf data is binary data and must be encoded for non-binary transport; Base64 [9] is suitable for Email. Kosonen & White Informational [Page 3]
RFC 4723 Mobile XMF MIME December 2006 Security considerations: Many synthetic audio compositions have associated intellectual property rights. It is conceivable that the rights owners of mobile-xmf 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; mobile-xmf content itself is not encrypted internally. mobile-xmf streams do not contain executable content. Mobile XMF players are robust against corrupted mobile-xmf content, because Mobile XMF players ignore unidentified content. prl, minimum-pr, and total-pr parameters can be used to represent Mobile DLS playback memory requirements for protecting against the excessive usage of playback memory. Interoperability considerations: Mobile XMF is a Musical Instrument Digital Interface (MIDI) specification developed by MMA and AMEI. Mobile XMF is based on the XMF Meta File Format Specification v2.00 [5,6], which standardizes a meta file format for the electronic distribution of music. mobile-xmf data is stored in XMF file format [5,6]. Published specification: Mobile XMF Content Format Specification, MMA specification v1.0., RP-42, Los Angeles, CA, USA. 2004. Specification is available from: http://www.midi.org/about-midi/specshome.shtml Applications which use this media type: mobile-xmf is a synthetic audio format for the flexible presentation of SP-MIDI and Mobile DLS instrument data on a wide range of playback devices, particularly portable appliances such as mobile phones, PDAs, and palmtop computers. Additional information: Magic number(s): First twelve bytes: \130\115\106\137\062\056\060\060\000\000\000\002 Kosonen & White Informational [Page 4]
RFC 4723 Mobile XMF MIME December 2006 File extension(s): mxmf Macintosh File Type Code(s): mxmf Person & email address to contact for further information: Timo Kosonen Email: timo.kosonen@nokia.com Intended usage: COMMON Restrictions on usage: none Authors: Timo Kosonen Email: timo.Kosonen@nokia.com Tom White Email: twhite@midi.org Change controller: MIDI Manufacturers Association P.O. Box 3173 La Habra, CA 90632-3173 Tel (714) 736-9774 Fax (714) 736-9775 Point of contact: Tom White Email: twhite@midi.org 3. Security Considerations Security considerations are specified in the MIME subtype registration contained in Section 2. 4. IANA Considerations Section 2 of this document registers one MIME subtype. Kosonen & White Informational [Page 5]
RFC 4723 Mobile XMF MIME December 2006 5. Normative References [1] Mobile XMF Content Format Specification, MMA specification v1.0., RP-42, Los Angeles, CA, USA. 2004. [2] Mobile DLS, MMA specification v1.0., RP-41, Los Angeles, CA, USA. 2004. [3] Scalable Polyphony MIDI Specification. December 2001, RP-034, The MIDI Manufacturers Association, Los Angeles, CA, USA. [4] Scalable Polyphony MIDI Device 5-24 Note Profile for 3GPP, December 2001, RP-035, The MIDI Manufacturers Association, Los Angeles, CA, USA. [5] Specification for XMF Meta File Format, Version 1.00b. The MIDI Manufacturers Association, Los Angeles, CA, USA, 2001. [6] XMF Meta File Format 2.00, RP-043, MIDI Manufacturers Association, Los Angeles, CA, USA, 2004 [7] 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. [8] Standard MIDI Files 1.0, In 'The Complete MIDI 1.0 Detailed Specification, Document Version 96.1.' The MIDI Manufacturers Association., Los Angeles, CA, USA. [9] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, October 2006. Kosonen & White Informational [Page 6]
RFC 4723 Mobile XMF MIME December 2006 Authors' Addresses Timo Kosonen Nokia P.O. Box 100 33721 Tampere Finland Tel: +358 5048 35206 Fax: +358 7180 35899 EMail: timo.kosonen@nokia.com Tom White MIDI Manufacturers Association P.O. Box 3173 La Habra, CA 90632-3173 USA Tel: (714) 736-9774 Fax: (714) 736-9775 EMail: twhite@midi.org Kosonen & White Informational [Page 7]
RFC 4723 Mobile XMF MIME December 2006 Full Copyright Statement Copyright (C) The IETF Trust (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, THE IETF TRUST, 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. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Kosonen & White Informational [Page 8]