Sustainability of Digital Formats: Planning for Library of Congress Collections |
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Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact |
Full name | WMA (Windows Media Audio) File Format |
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Description | File format based in ASF (Advanced Systems Format) that wraps an audio bitstream. This web site documents versions of the format that contain bitstreams encoded by Windows Media Audio 9. Some WMA files may also employ Windows Media Audio 7 and 8 codecs. |
Production phase | Usually a final state format for end user delivery; sometimes a middle-state format, e.g., a high-quality audio representation for archiving or as a source when producing lower-resolution streaming versions. |
Relationship to other formats | |
Subtype of | ASF, Microsoft Advanced Systems Format. |
Has subtype | WMA_WMA9, Windows Media Audio File with WMA9 Codec |
Has subtype | WMA_WMA9_PRO, Windows Media Audio File with WMA9 Professional Codec |
Has subtype | WMA_WMA9_LL, Windows Media Audio File with WMA9 Lossless Codec |
Has subtype | WMA file-format variants defined by other audio codecs, not documented at this time. |
LC experience or existing holdings | The Library of Congress has a small amount of Windows Media Audio files in its collections. |
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LC preference | See the Library of Congress Recommended Formats Statement for format preferences for audio works. |
Disclosure | Microsoft's proprietary ASF wrapper format is fully documented. For information about the disclosure of information about the bitstreams wrapped by WMA, see the descriptions of individual codecs listed under Relationships, above. |
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Documentation | For wrapper documentation, see ASF. See also citations in Useful references below. |
Adoption | Widely adopted. |
Licensing and patents | See ASF. |
Transparency | See information on versions that incorporate different codecs: WMA_WMA9, WMA_WMA9_PRO, and WMA_WMA9_LL. |
Self-documentation | See ASF |
External dependencies | None |
Technical protection considerations | See ASF |
Sound | |
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Normal rendering | Good support. |
Fidelity (high audio resolution) | Moderate to excellent; outcome will depend on codec selected and upon the type and level of compression. |
Multiple channels | Supported in WMA_WMA9_PRO |
Support for user-defined sounds, samples, and patches | Appears to be some support for MIDI_SD; not investigated at this writing. |
Functionality beyond normal rendering | Support for various elements offered by ASF. |
Tag | Value | Note |
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Filename extension | wma |
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Internet Media Type | audio/x-ms-wma |
Selected from The File Extension Source. Also in LC implementation of Apache mime.types. |
Magic numbers | Hex: 30 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C ASCII: 0&²u.fÏ.¦Ù.ª.bÎl |
For extension asf (see ASF), from Gary Kessler's File Signatures Table. |
ASF GUID | F8699E40-5B4D-11CF-A8FD-00805F5C442B |
Globally Unique IDentifier for ASF_Audio_Media; from Advanced Systems Format (ASF) Specification. |
Pronom PUID | fmt/132 |
See http://www.nationalarchives.gov.uk/PRONOM/fmt/132. |
Wikidata Title ID | Q2194 |
See https://www.wikidata.org/wiki/Q2194. |
General | |
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History |
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