MKV. Format (Container format) for video files, and the Mac keep track of an unlimited number of video, audio and subtitles in Matroska file format is. If you wish to keep track of video, audio and subtitles in an MKV file format, delete or add to it, or ask a new file based on the Matroska video format mp4, avi, … or srt subtitles . And sub. Etc., you can use the software MKVToolnix use. Using this software, you can file with subtitles in SRT format  intended to merge MKV format when handling or movies easily and click on the video file to play movies. The software has a lot of speed and combined operations without compromising the quality of the movie.