For those unfamiliar, MKV (Matroska Multimedia Container) is an open standard free container that is popularly use on high-definition videos. In particular MKV files are heavy popular on pirated copies of movies and TV shows through file sharing sites and Bit Torrent. Nevertheless, there are many legitimate reasons for Microsoft to add native support to Windows.   Up until now users had to install the codec or download a piece of software like VLC to play MKV files, but with the new video app update, Microsoft is pushing one more element to make the Windows experience more seamless between screens and versions of the operating system. Although we are moving toward an online streaming video model instead of physical media or download model, having MKV natively supported in Windows adds another way for users to play and share video content without having to resource to third-party applications. Keep in mind that Microsoft adding MKV support to Windows 8.1 does not necessarily mean that you can play every single video with the extension .mkv, as the support is limited to the codec and subtitle implementation. However, we can assume that it will improve in future updates. Source Microsoft All content on this site is provided with no warranties, express or implied. Use any information at your own risk. Always backup of your device and files before making any changes. Privacy policy info.