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 | WMV (Windows Media Video) File Format |
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| Description | File format based on ASF (Advanced Systems Format) that wraps a video bitstream. This web site documents versions of the format that contain bitstreams encoded by Windows Media Video 9, which is also known as VC-9. Some WMV files may also employ Windows Media Video 7 and 8 codecs. |
| Production phase | Often final state format for end user delivery; sometimes a middle-state format, e.g., a high-quality video representation for archiving or as a source when producing lower-resolution streaming versions. |
| Relationship to other formats | |
| Subtype of | ASF, Advanced Systems Format. From Microsoft. |
| Has subtype | WMV_WMV9, Windows Media Video File with WMV9 Codec |
| Has subtype | WMV_WMV9_PRO, Windows Media Video File with WMV9 Professional Codec |
| Has subtype | WMV file-format variants defined by other video codecs, not documented at this time. |
| LC experience or existing holdings | The Library of Congress has a small amount of Windows Media Video files in its collections. |
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| LC preference |
See the Library of Congress Recommended Formats Statement for format preferences for file-based video. |
| Disclosure |
Microsoft's proprietary ASF wrapper format is fully documented. For information about the disclosure of information about the bitstreams wrapped by WMV, 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 |
Supported for playback in Microsoft products such as Windows Media Center and Windows Media Player. For Windows Movie Maker in Windows XP (link available through Internet Archive), it is one of two output formats for video. In 2004, AtomFilms (which became Atom.com and later CC:Studios) announced the use of Windows Media High-Definition Video at 720p resolution for their high definition service. Comments welcome. |
| Licensing and patents | See ASF. |
| Transparency |
File format is transparent. See information on versions that incorporate different codecs: WMV_WMV9 and WMV_WMV9_PRO. |
| Self-documentation | See ASF |
| External dependencies | None |
| Technical protection considerations | See ASF |
| Moving Image | |
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| Normal rendering | Good support. |
| Clarity (high image resolution) | Depends upon encoding; see WMV9 or WMV9_PRO |
| Functionality beyond normal rendering | Support for various elements offered by ASF |
| Sound | |
| Fidelity (high audio resolution) | Moderate to excellent; outcome will depend on codec selected and upon the type and level of compression. |
| Multiple channels | Depends upon encoding; see WMA9_PRO |
| Support for user-defined sounds, samples, and patches | [Not investigated at this writing.] |
| Tag | Value | Note |
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| Filename extension | wmv |
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| Internet Media Type | video/x-ms-wmv |
From The File Extension Source. No examples found in IANA MIME Media Types or 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 | BC19EFC0-5B4D-11CF-A8FD-00805F5C442B |
Globally Unique IDentifier for ASF_Video_Media; from Advanced Systems Format (ASF) Specification. |
| Pronom PUID | fmt/133 |
See http://www.nationalarchives.gov.uk/PRONOM/fmt/133 |
| Wikidata Title ID | Q280761 |
See https://www.wikidata.org/wiki/Q280761 |
| General | |
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| History |
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