They are Windows Media formats. One is Audio & the other is Video. Not well liked formats by those people who know anything about audio & video. Also due to their DRM capabilities which are abused, you end up with some asking for licencing but actually want you to connect to the net set up by diallers, marketers & porn sites. Beware. Also see What you should know about WMA Files which also applies to WMV. Of course they are designed for WMP (player.) But many other audio programs & some portable players can play them.