WHAT IS WEBM?
Web Media File
On2, Xiph, and Matroska; now supported by Google
WebM stands for Web Media File. It is an open, royalty-free, audiovisual file format created in 2010 specifically for the web. If you are not sure how to play a WebM file, you’ll find information about the WebM format specification and a list of programs that support playback of these files below.
The WebM file type is used in HTML5 video and audio elements. It supports variable video frame rates and audio bitrates. In a WebM file, the video stream is compressed with VP8 or VP9 video codecs, and the audio stream with Vorbis or Opus audio codecs.
QuickTime Player, Google Chrome, Opera, Mozilla Firefox, YouTube, and Adobe Flash Player