... v4 (.MKV) file container is an open-source alternative to proprietary containers such as MP4 (Apple) and WMV (Microsoft), and version four, which was launched in September 2012, introduced new elements to improve time-coding and seek-positioning ...
http://betanews.com/2013/04/14/vlc-media-player-2-0-6-is-full-of-tweaks/
http://betanews.com/2013/04/14/vlc-media-player-2-0-6-is-full-of-tweaks/
