WebM is an open-source, royalty-free multimedia format for streaming content online. It contains compressed video streams of either VP8 or VP9 codec and compressed audio streams of Oupus or Vorbis codec. Today, it’s one of the most widely used file formats to stream videos online because of its lightweight and real-time delivery nature.
Google Chrome Firefox VLC Media Player Windows Media Player
OGV is a digital video container format related to the encoding technology of the OGG Vorbis video. It can save multiple related video stream codecs like the DivX and Theora. It is these codecs that allow OGV files to open on varying media players.
MPLayer Classic VLC Media Player Jriver Media Center MPUI