WMV

WMV (Windows Media Video) is a video format developed by Microsoft and used in a number of proprietary codecs (with several different versions of the format released), but eventually released as an open standard (known as VC-1) for interoperability with other vendors. When stored as a computer file, it is usually contained within the ASF container format, and given a file extension of .wmv. The WMV format is also used as one of the video formats contained on BluRay Discs.

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.

Links

 * WMV: Wikipedia article
 * VC-1: Wikipedia article
 * Windows Media encryption algorithm description