FLV is a video file format developed by Adobe Systems. The name is an abbreviation of the full name Flash Video File. FLV format video files are Flash-compatible and usually contain various metadata (titles, audio, video, etc.). FLV-files are widely spread on the global network, in this format they make streaming video for YouTube, MySpace and other video hosting sites. Compared with similar formats, video files have a higher compression ratio. FLV files are easily converted to more common video formats.
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.