Sustainability of Digital Formats
 Planning for Library of Congress Collections

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Identification and description

Full name	Standard MIDI File Format
Description	Wrapper format for MIDI data. From the specification from MIDI.org (an arm of the MIDI Manufacturers Association): "This chunk architecture is similar to that used by the Electronic Arts IFF format, and the chunks described herein could easily be placed in an IFF file. The MIDI file itself is not an IFF file: it contains no nested chunks, and chunks are not constrained to be an even number of bytes long." (Section 4, p. 3)
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
Contains	MIDI_SD, MIDI sequence data

Local use

LC experience or existing holdings	None
LC preference	None established at this time

Sustainability factors

Disclosure	Fully documented. Developed by the MIDI Manufacturers Association.
Documentation	The Complete MIDI 1.0 Detailed Specification (2001), available for purchase from MIDI.org.
Adoption	See MIDI_SD.
Licensing and patent claims	See MIDI_SD.
Transparency	Transparent wrapper. See also MIDI_SD.
Self-documentation	Header chunks are used to identify track chunks within the file; Meta-Events include sequence information, text inclusions, copyright notices, track names, and more.
External dependencies	See MIDI_SD.
Technical protection considerations	None known to the compilers of this document.

Quality and functionality factors

Normal rendering for sound	Not applicable; see MIDI_SD.
Fidelity (support for high audio resolution)	Not applicable; see MIDI_SD.
Support for multiple sound channels	Not applicable; see MIDI_SD.
Support for downloadable or user-defined sounds, samples, and patches	No; see XMF.
Functionality beyond normal rendering for sound	See MIDI_SD. The compilers of this document have not investigated the degree to which such added functionality is provided by SMF as distinct from other file formats and/or application software. See Notes for comment on karaoke applications.

File type signifiers

Tag type	Value	Note
Filename Extension	mid, midi	Selected from The File Extension Source. Also listed at the site: mff, mdi, and kar for karaoke MIDI files; see also Notes.
Internet Media Type	audio/mid audio/m audio/midi audio/x-midi application/x-midi	Selected from The File Extension Source; for kar karaoke files, x-music/x-midi is added. No Internet Media Type for MIDI found at http://www.iana.org/assignments/media-types/.
Magic numbers	Hex: 4D 54 68 64 ASCII: MThd	From Gary Kessler's File Signatures Table. The File Extension Source reports this for Hex: 4D 54 68 64 00 00 00 06 00 01 00.

Notes

General

MIDI data is placed in numerous types of files, including files used in games and specialized devices. One alternative to SMF is RMID, based in the Microsoft RIFF specification but deprecated at the MIDI.org site. The File Extension Source reports that "the .KAR [karaoke] file format was designed by Tune 1000 Corp. They have abandonded it, but it is still the prevailing file format in shareware/public domain market. Other Karaoke formats include: .MID+.TXK, .MID, .CRT, and .ST3. . . . Various programs use this extension; too many to list individually."

History

See MIDI_SD.

Format specifications

URLs

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• The Complete MIDI 1.0 Detailed Specification (2001), available for purchase from MIDI.org (http://www.midi.org/about-midi/specshome.shtml)

Useful references

URLs
• See MIDI_SD.
• Gary Kessler's File Signatures Table (http://www.garykessler.net/library/file_sigs.html).
• The File Extension Source (http://filext.com/)

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