Sustainability of Digital Formats: Planning for Library of Congress Collections
Sustainability of Digital Formats: Planning for Library of Congress Collections |
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| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | XMF, eXtensible Music File Format, Version 1.0 |
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| Description |
XMF is a wrapper format for MIDI, Downloadable Sounds (DLS), and WAVE waveform data. From the specification from MIDI.org: "XMF is low-overhead meta-file format . . . . primarily intended to bundle existing standard music and sound file formats--such as SMF, DLS_1_1b, and WAV--and not to replace any of them." (RP-030, p.2) MIDI and audio data may be encapsulated in the XMF file or be linked via external URI reference. The MIDI Manufacturers Association FAQ states, "The most popular use of XMF is currently for mobile phone content, via the Mobile XMF file type." The second part of the specification (RP-031) discusses Type 0 and Type 1 files: "both must contain at least one SMF file; inclusion of DLS files is optional" (p. 1), and "the SMF file images in an XMF Type 0 file are guaranteed to be streamable." (RP-031, p. 2) [Is there a type that only contains external references to SMF and/or DLS data?] Later versions of the meta file format (1.01 and 2.0 at this writing) define a set of four file types as outlined in Notes below. |
| Production phase | May be used by composers or arrangers for initial-state activities, in middle-state exchange of data or archiving, or for final-state, end-user delivery. |
| Relationship to other formats | |
| May contain | MIDI_SD, MIDI Sequence Data |
| May contain | DLS_1_1b, Downloadable Sounds Format, Version 1.1b |
| Has later version | XMF, eXtensible Music File Format, Version 1.01, not documented at this Web site. |
| Has later version | XMF, eXtensible Music File Format, Version 2.00, not documented at this Web site. |
| LC experience or existing holdings | None. |
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| LC preference | See the Library of Congress Recommended Formats Statement for format preferences for Audio Works. |
| Disclosure | Fully documented. Developed by the MIDI Manufacturers Association. |
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| Documentation | The XMF (eXtensible Music Format), Version 1.0 (2001) contains three parts: RP-030, general specification; RP-031, Type 1 and Type 0 files; and RP-032, meta event and patch type prefix. As of February 2011, this version was no longer offered from MIDI.org, although the successor versions were available there. |
| Adoption | The MIDI Manufacturers Association FAQ states, "Many mobile phones can already open and play Mobile XMF files." The compilers of this document have not confirmed the accuracy of this statement. Comments welcome. |
| Licensing and patents | The MIDI Manufacturers Association FAQ states, "XMF is freely usable. The only thing you have to pay for is buying the specification documents." |
| Transparency | Transparent wrapper. See also MIDI_SD and DLS_1_1b. |
| Self-documentation | Provided by MetaDataItems, which may be placed at any node in the file and may include technical, copyright, or descriptive information, e.g., title, name, author, etc. The specification speaks of a future plan to specify an XML semantic equivalent to the current mechanism. |
| External dependencies | See MIDI_SD and DLS_1_1b. |
| Technical protection considerations | None known to the compilers of this document. |
| Sound | |
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| Normal rendering | Not applicable; see MIDI_SD and DLS_1_1b. |
| Fidelity (high audio resolution) | Not applicable; see MIDI_SD and DLS_1_1b. |
| Multiple channels | Not applicable; see MIDI_SD. |
| Support for user-defined sounds, samples, and patches | Yes, when an XMF instance contains or references DLS_1_1b. |
| Functionality beyond normal rendering | The XMF specification (RP-032) discusses Meta-Events pertaining to assignment of data to instruments in an XMF context. See also MIDI_SD; the compilers of this document have not investigated the degree to which such added functionality is provided by XMF as distinct from other file formats and/or application software. |
| Tag | Value | Note |
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| Filename extension | xmf |
Suggested by the specification. |
| Filename extension | mxmf |
For Mobile-XMF, from https://www.iana.org/assignments/media-types/audio/vnd.nokia.mobile-xmf. |
| Internet Media Type | audio/mobile-xmf |
From The File Extension Source, for Mobile-XMF. See also https://www.iana.org/assignments/media-types/audio/vnd.nokia.mobile-xmf: audio/vnd.nokia.mobile-xmf |
| Magic numbers | Hex: 58 4D 46 5F ASCII: XMF_ |
From The File Extension Source, for Mobile-XMF. |
| Pronom PUID | fmt/961 |
See http://www.nationalarchives.gov.uk/PRONOM/fmt/961. |
| Wikidata Title ID | Q50308902 |
See https://www.wikidata.org/wiki/Q50308902. |
| General |
In March 2024, the MIDI Manufacturers Association Web site XMF page outlined the current set of XMF specifications behind a log-in wall:
Wikipedia MIDI article (consulted February 25, 2011): "The MMA [MIDI Manufacturers Association] has also defined (and AMEI [Association of Musical Electronics Industry, a Japan-based trade group] has approved) a new family of file formats, XMF (Extensible Music File), some of which package SMF chunks with instrument data in DLS format (Downloadable Sounds, also an MMA/AMEI specification), to much the same effect as the MOD file format. The XMF container is a binary format (not XML-based, although the file extensions are similar)." From https://www.iana.org/assignments/media-types/audio/vnd.nokia.mobile-xmf (2004): "Mobile XMF is a Musical Instrument Digital Interface (MIDI) specification developed by MMA and AMEI." |
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| History | The development of XMF post-dates that of RMID, the use of which is deprecated (link via Internet Archive) at the MIDI.org web site. |
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