How to Play MKV Files
Although the Matroska, or MKV, container holds a significant advantage over other media formats due to its compatibility with most types of audio, video and subtitle formats, the codecs required to play MKV files are not present by default in Windows 8.1. You can, however, acquire the codecs required for MKV playback via Windows Media Player free of charge by installing the CCCP codec package. Alternately, you can opt to install an MKV-compatible media player if you prefer avoiding the codec pack installation.
Get MKV Playback Functionality
Visit the CCCP-Project.net home page (link in Resources) and click the “Download CCCP” button to get the CCCP codec package. During installation, select “Full Installation” if you want to install the Media Player Classic application alongside the codec package. After installation, right-click the MKV file that you need to play, point to “Open With,” then select either “Windows Media Player” or “Media Player Classic” to play it. If you selected Media Player Classic, right-click within any portion of the window, then use the Audio, Video and Subtitle sub-menus to switch between available tracks. Alternately, you can install the KMPlayer or the VLC Player (links in Resources), which use integrated codecs for video playback, to get MKV functionality without having to install the CCCP codec package.