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Network Working Group                                          P. FrojdhRequest for Comments: 4613                                   U. LindgrenCategory: Informational                                    M. Westerlund                                                                Ericsson                                                          September 2006Media Type Registrations for Downloadable Soundsfor Musical Instrument Digital Interface (MIDI)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 Internet Society (2006).Abstract   This document serves to register a media type for Downloadable   Sounds.Table of Contents1. Introduction ....................................................12. Security Considerations .........................................23. IANA Considerations .............................................23.1. Media Type for Downloadable Sounds .........................34. References ......................................................54.1. Normative References .......................................54.2. Informative References .....................................51.  Introduction   The present document seeks to register a media type for Downloadable   Sounds (DLSes).  The DLS format is used to define instruments for   widely used wavetable synthesizers associated with the standards   [DLS1,DLS2,MDLS].  DLSes and their associated standards are   maintained and defined by two organizations, the Musical Instrument   Digital Interface (MIDI) Manufacturers Association (MMA) and the   Association of the Musical Electronics Industry (AMEI).   The media type defined here is needed to identify DLS files correctly   when they are served over HTTP, included in multi-part documents, or   used in other places where media types are used.Frojdh, et al.               Informational                      [Page 1]

RFC 4613           Media Type Registrations for MIDI      September 20062.  Security Considerations   The DLS format may contain audio, displayable text data, and modeling   parameters (a.k.a. articulation parameters).  In addition, the DLS   format contains a so-called conditional chunk that is 'active' in the   sense that it affects the execution of a DLS file parser.  However,   the DLS format does not currently define any scripting mechanism.   Clearly, it is possible to author malicious files that, for example,   contain large amounts of data always blocked by a conditional   statement; i.e., no synthesizer loads the instruments.   However, for DLS, clients can and usually do protect themselves   against these kinds of attacks.  A key point is that conditional   chunks are optional, that is, a parser does not have to execute a   conditional chunk.  However, if a parser evaluates a conditional   chunk, it is still possible to parse its content and draw to a   conclusion as to whether it is usable for a particular synthesizer   engine.   Note that selected metadata fields may include information partly   intended to protect the media against unauthorized use or   distribution.  In this case, the intention is that alteration or   removal of the data in the field would be treated as an offense under   national agreements based on World Intellectual Property Organization   (WIPO) treaties.   DLS have an extensible structure, making it theoretically possible to   define metadata fields or media formats in the future that could be   used to induce particular actions of the recipient, and thus that   would present additional security risks.  However, this type of   capability is currently not supported in the referenced   specifications.   There is no current provision in the DLS standard for encryption,   signing, or authentication within the file formats.3.  IANA Considerations   The IANA has registered the media type audio/dls, as specified inSection 3.1.  The registration uses the template present in   [RFC4288].Frojdh, et al.               Informational                      [Page 2]

RFC 4613           Media Type Registrations for MIDI      September 20063.1.  Media Type for Downloadable Sounds   Type name:                         audio   Subtype name:                      dls   Required parameters:               None   Optional parameters:               'dls-type'                                      A comma-separated list of the                                      dls types (one or more) that the                                      file content conforms to.  The                                      following values are specified:                                      0, 1, and 2 signify Downloadable                                      Sounds Level 1.1b content,                                      Downloadable Sounds Level 2.1                                      content, and Mobile Downloadable                                      Sound content, respectively.  All                                      types that the content conforms                                      to should be indicated.  Further                                      values (integers) may be                                      specified in the future, and any                                      unknown values shall be ignored.                                      If the parameter is not                                      specified, it corresponds to a                                      value equal to 0; i.e., the                                      content conforms to Downloadable                                      Sound level 1.1b.   Encoding considerations:           DLS files are binary and should                                      be transmitted in a suitable                                      encoding without CR/LF                                      conversion, 7-bit stripping                                      etc.; base64 [RFC3548] is a                                      suitable encoding.   Security considerations:           see the security considerations                                      inSection 2 of RFC 4613.   Interoperability considerations:   This media type is for                                      consumption by a MIDI player                                      capable of utilizing                                      downloadable sounds for its                                      synthesizers.  A general-purpose                                      audio player will not be capable                                      of utilizing the audio within                                      the format without explicit                                      support of the format.Frojdh, et al.               Informational                      [Page 3]

RFC 4613           Media Type Registrations for MIDI      September 2006   Published specification:           Downloadable Sounds Level 1.1b                                      [DLS1], Downloadable Sounds                                      Level 2.1 [DLS2], and Mobile                                      Downloadable Sounds [MDLS].  MMA                                      specifications can be ordered                                      from the MMA web site,                                      www.midi.org.   Applications that use this media type: Multi-media   Additional information:      Magic number(s):                The ninth to twelfth bytes of                                      the file must equal (in                                      hexadecimal notation) 44, 4c,                                      53, and 20, respectively.      File extension(s):              .dls is declared athttp://www.nist.gov/nics   Person & email address to contact for further information:                                      Ulf A. Lindgren,                                      ulf.a.lindgren@ericsson.com   Intended usage:                    COMMON   Restrictions on usage:             None   Author:                            Per Frojdh                                      Ulf A. Lindgren                                      Magnus Westerlund   Change controller:                 MIDI Manufacturers Associationhttp://www.midi.orginfo@midi.orgFrojdh, et al.               Informational                      [Page 4]

RFC 4613           Media Type Registrations for MIDI      September 20064.  References4.1.  Normative References   [DLS1]     "Downloadable Sounds Level 1.1b", MMA/AMEI specification              v1.1b, Los Angeles, CA, USA, 2004.   [DLS2]     "Downloadable Sounds Level 2.1", MMA/AMEI specification              v1.0, Los Angeles, CA, USA, 2001.   [MDLS]     "Mobile Downloadable Sounds 1.0", MMA specification v1.0,              Los Angeles, CA, USA, 2004.   [RFC4288]  Freed, N. and J. Klensin, "Media Type Specifications and              Registration Procedures",BCP 13,RFC 4288, December 2005.4.2.  Informative References   [RFC3548]  Josefsson, S., "The Base16, Base32, and Base64 Data              Encodings",RFC 3548, July 2003.Authors' Addresses   Per Frojdh   Ericsson AB   Ericsson Research   SE-164 80 Stockholm   Sweden   EMail: per.frojdh@ericsson.com   Ulf A. Lindgren   Ericsson AB   Ericsson Research   SE-417 56 Goteborg   Sweden   EMail: ulf.a.lindgren@ericsson.com   Magnus Westerlund   Ericsson AB   Ericsson Research   SE-164 80 Stockholm   Sweden   EMail: magnus.westerlund@ericsson.comFrojdh, et al.               Informational                      [Page 5]

RFC 4613           Media Type Registrations for MIDI      September 2006Full Copyright Statement   Copyright (C) The Internet Society (2006).   This document is subject to the rights, licenses and restrictions   contained inBCP 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.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 inBCP 78 andBCP 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 athttp://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 provided by the IETF   Administrative Support Activity (IASA).Frojdh, et al.               Informational                      [Page 6]