A container format used to stream video using the HTML5 video tag. It can contain VP8 or VP9 compressed video as well as Vorbis or Opus compressed audio.
VP8 is comparable to H.264 in quality while Vorbis is much more performant at compressing audio than MP3. VP9 is an improvement to VP8 while Opus is designed for both music and speech.
This tag implicates animated (learn more).