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 | Audio Interchange File Format (AIFF) |
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| Description | File format for sound that wraps various sound bitstreams, ranging from uncompressed waveform to MIDI. Files with LPCM waveform data are the focus of this discussion. Compressed waveforms are wrapped by AIFF-C (or an earlier version sometimes referred to as AIFC), not documented at this web site. |
| Production phase | Used primarily as a initial- or middle-state format, including use as a master file for audio captured live digitally or reformatted from analog sources. |
| Relationship to other formats | |
| Subtype of | IFF, Electronic Arts Interchange File Format 1985 |
| Has subtype | AIFF_LPCM, AIFF with LPCM Audio |
| Has subtype | AIFF-C in which the "C" signifies its extension to handle compressed audio data (August 1991, not documented at this Web site at this time) |
| Has subtype | AIFF files may contain other sound encodings not documented here |
| May contain | LPCM, Linear Pulse Code Modulated Audio (LPCM). encoded audio |
| May contain | MIDI_SD, MIDI sequence data |
| May contain | Other sound encodings, not documented here |
| LC experience or existing holdings | None |
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| LC preference | General preference for recorded sound is WAVE_LPCM. |
| Disclosure |
Fully documented. Developed by Apple Computer, Inc. |
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| Documentation |
AIFF and AIFF-C documentation produced by Apple and carrying no copyright notice is available from third parties. The principal document is titled Audio Interchange File Format (AIFF): A Standard for Samples Sound Files, Version 1.3 (Apple Computer, Inc) and it also forms Annex C to the CD-I IFF specification published by the American Interactive Media group. The compiler of this document was unable to locate the specifications at the Apple web site. |
| Adoption |
Widely adopted among Apple users engaged in professional audio work; some adoption beyond, although most Windows users select WAVE, which is functionally equivalent. AIFF_LPCM is used as the master format by the Harvard University Library Digital Initiative audio reformatting activity. |
| Licensing and patents |
None known to the compilers of this document. |
| Transparency |
Wrapper is transparent. The transparency of the audio bitstreams is a function of the encoding used; for example, see LPCM. |
| Self-documentation |
AIFF includes various chunks, each with a header that provides technical information; text chunks as defined from the supertype IFF format include name, author, copyright, and annotation. |
| External dependencies | None |
| Technical protection considerations |
None known to the compilers of this document. |
| Sound | |
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| Normal rendering | Good support. |
| Fidelity (high audio resolution) | Excellent to good, depending upon encoding parameters selected. |
| Multiple channels | Mono, stereo, 3-channel, quad, and four and six channel surround sound are supported for waveform data, depending upon encoding; MIDI data may carry multi-channel information. [?] |
| Support for user-defined sounds, samples, and patches | Not researched for this document |
| Functionality beyond normal rendering | Not applicable; added functionality may be associated with non-waveform data. |
| Tag | Value | Note |
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| Filename extension | aif aiff ief |
aif is most widely used as a file extension. Wikipedia reports use of aiff. Webopedia reports that ief is used as an extension. |
| Internet Media Type | audio/aiff audio/x-aiff sound/aiff audio/rmf audio/x-rmf audio/x-pn-aiff audio/x-gsm audio/x-midi audio/vnd.qcelp |
From The File Extension Source. Note that encoding, e.g., gsm, midi and qcelp, is often a part of the MIME string. Internet Media Type for AIFF not found at https://www.iana.org/assignments/media-types/. |
| Magic numbers | Hex: 46 4F 52 4D 00 ASCII: FORM |
From The File Extension Source. |
| Mac OS file type | AIFF |
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| Pronom PUID | fmt/414 |
See https://www.nationalarchives.gov.uk/PRONOM/fmt/414 for version 1.2. |
| Wikidata Title ID | Q758853 |
See https://www.wikidata.org/wiki/Q758853. |
| General | |
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| History |
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