Sustainability of Digital Formats: Planning for Library of Congress Collections

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Windows Media 9 Audio Codec

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name Windows Media 9 Audio Codec
Description Audio bitstream produced by the Windows Media 9 audio codec.
Production phase Generally used in files that represent a final-state format for end-user delivery.
Relationship to other formats
    Used by WMA_WMA9, Windows Media Audio file with WMA9 codec

Local use Explanation of format description terms

LC experience or existing holdings  
LC preference See WMA

Sustainability factors Explanation of format description terms

Disclosure Proprietary. Developed by Microsoft.
    Documentation Specifications not disseminated.
Adoption Not known to the compilers of this document; the WMA file format is widely adopted.
    Licensing and patents See ASF for link to pages covering licensing of Windows Media and the Advanced Systems Format.
Transparency Depends upon algorithms and tools to read; will require sophistication to build tools.
Self-documentation Not applicable
External dependencies None
Technical protection considerations Not applicable

Quality and functionality factors Explanation of format description terms

Sound
Normal rendering Good support.
Fidelity (high audio resolution) From the codecs page at the Microsoft Windows Media web site (consulted September 1, 2010): "For use in most scenarios. This codec . . . supports VBR [variable bit rate] audio that enables even higher quality audio at smaller file sizes. Windows Media Audio 9 is backward-compatible with previous Windows Media Audio-compatible decoders." The site indicates that higher quality is provided by WMA9_PRO.
Multiple channels None
Functionality beyond normal rendering Not applicable

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension Not applicable.   
Internet Media Type Not applicable.   
Magic numbers Not applicable.   

Notes Explanation of format description terms

General  
History  

Format specifications Explanation of format description terms


Useful references

URLs


Last Updated: Tuesday, 21-Feb-2017 08:55:47 EST