WMA
From Just Solve the File Format Problem
WMA (Windows Media Audio) is an audio format and codec developed by Microsoft and used as the native format for compressed audio to be played in Windows Media Player, as WMV is for video. As a file format, WMA is usually contained within an ASF container format.
The normal WMA format is lossy (it loses some of its data in the course of compressing it), but there is a WMA Lossless variant, as well as another version optimized for speech rather than music.
WMV does not inherently contain Digital Rights Management (DRM), but the ASF container format was designed with the possibility of DRM in mind, so some of these files are so encumbered.
