Files with the .MKV extension contain multimedia data - video images, as well as many soundtracks and subtitles. It is similar to other formats - containers such as AVI, ASF, MOV. It supports SRT, SSA, VobSub subtitles from DVF discs, USF, which stands for Universal Subtitle Format, as well as various types of audio and video codecs.

MKV (Matroska Video) files have become popular thanks to their ability to support multiple soundtracks and subtitles, for example in different languages. Communities creating their own anime subtitles are what popularized the MKV format. On Mac OS and Windows computers, the files can be played using DivX Player software, and, on Palm, Symbian, and Pocket PC mobile devices, using CorePlayer Mobile.