It has better support than MP4 for some features like subtitles, multiple video and audio tracks and chapters. MKV is also the basis of WebM video, which is dedicated to developing a high-quality, open video format for the web that is freely available to everyone.
MKV is a flexible, open standard video file format wildly used for HD videos.
MKV (Matroska) and MP4 (MPEG-4) are both container formats to store video and audio.
