OGV is a video file format that uses an open OGG container. The name of the format is also associated with this - an abbreviation for Ogg Video File. The developer of both formats is Xiph.Org. The OGV format stores video streams that use either one or several different codecs (for example, Theora). OGV files can be played on almost any media player. They are also used when displaying web pages using HTML5, however, these files (even videos) often have the .OGG extension. OGV video compression is lossy.
MKV is an open container format for audio and video data created by Russian developers. The name of the format originates from the name of the project - Matroska (Matryoshka) with the addition of the first letter of the word Video. This format is considered an alternative to the much more popular AVI, but has not yet reached such a scale of distribution. MKV files are quite common among owners of fairly old mobile devices with Symbian OS and at the same time among those who prefer to watch video in FullHD, since MKV has good dynamics of transmitting video / audio streams. MKV with a wide range of features, in particular, storing audio tracks in different languages, is easy to edit, there are no freezes in large files.