WebM is a format that contains multimedia files, and uses the VP8 and VP9 video codecs, in addition to the Opus and Vorpis audio codecs. It is an open source project, so it is available for any user to work with and modify without having to pay royalties.
It is intended for use with little computing power, being ideal for use in HTML5. Its main objective is to allow online video playback on any device, being the format chosen by YouTube when converting all its videos.
Although Google is still committed to the WebM format, other major companies such as Microsoft and Apple continue to use MP4. The major browsers such as Chrome, Opera or Firefox provide factory support for WebM, so there is no need to download an additional plugin to use it. As for the most used program to play WebM files, we must highlight VLC Player.